Study on Structure and Magnetic Properties of Rare Earth Transition Metal Intermetallic Compounds
The new class of R(rare earth)-T(transition metal) intermetallics namely,R3(Fe,M)29 (R =Ce, Pr,Nd, Sm, Gd, Tb,Dy, Y; M =Ti,V,Cr,Mn,Mo,Nb,W ) are of current interest in the field of permanent magnet materials. Based on the study on R-T permanent-magnet material Nd3(Fe,Ti)29, this thesis deals with a study of the structural and magnetic properties as well as the the magnetocrystalline anisotropy. Below, the main experimental results and conclusions are summarized:1. A rare-earth-transition metal intermetallic compound is a candidate for excellent permanent materials when it fulfills the following conditions: it must has a large spontaneous magnetization, a strong uniaxial magnetocrystalline anisotropy and a high magnetic ordering temperature . Since the R3(Fe,M)29 phase is an intermediate phase between the ThMn12 and Th2Zn17-type structures, production of the single R3(Fe,M)29 is difficulty and time consuming. For example,the Nd3(Fe,Ti)29 phase is usually produced by annealing of Nd–Fe–Ti alloy ingots at a high temperature of 1373K for a long period of 72–130h. The annealed Nd–Fe–Ti alloy still contains a small amount ofα-Fe phase.
We study the structure and magnetic properties of Nd–Fe–Ti alloy abtained by annealing of Nd–Fe–Ti ribbons produced by the melt-spinning technique. The XRD patterns and thermomagnetic curves show that the melt-spinning ribbons and the alloys annealed at a low temperature contain a large amount of Nd2(Fe,Ti)17 phase together withα-Fe phase. Substitution of Ti for Fe does not lead to a change of crystal structure, all alloys are in Th2Zn17-type structures. With increasing Ti content Curie temperature TC decrease monotonously . The Tc decrease from 503K to 483K for as-spun ribbons and 493K to 463K for 873K annealed alloys, respectively. Substitution of Ti for Fe may reduce the amount of magnetic ion, therefore the Tc decrease monotonously.2. In order to improve the intrinsic magnetic properties of Nd3(Fe,Ti)29 type compounds, such as saturation, magnetization, Curie temperature, and magnetocrystalline, anisotropy, in addition to formation of nitrides of these compounds, ion substitution is also an effective method. Recently some investigations of substitution of Co for Fe have been carried out. It has been found that substitution of Co for Fe leads to a transition of magnetocrystalline anisotropy compounds. From basal plane to uniaxial in Gd3( Fe,Co) 25Cr4.
In this thesis we study on substitution of Co for Fe in Nd3(Fe,Ti)29 alloys produced by melt-spinning technique. XRD patterns and thermomagnetic curves show that the melt-spinning ribbons contain a large amount of Nd2(Fe,Ti)17 phase together withα-Fe phase. Substitution of Co for Fe does not lead to a change of crystal structure, all alloys are in Th2Zn17-type structures. It is worth noting that the saturation magnetization increases monotonically with Co concentra tion. But due to the smaller atomic radius of the Co atom compared wit Fe, TC of Nd3Fe27.6-xCoxTi1.4 compounds increases strongly with increasing Co content. It is 453K when x=0 and in increase to 675K when x=6.0.3. In order to find out the effect that Gd substitute Nd in Nd3(Fe, Ti)29 compound, we investigate the structure and magnetic properties of (Nd1-xGdx)Fe27.31Ti1.69 compounds by XRD and magnetic measurements. All compounds with x in the range of x≤0.6 crystallize in Nd3(Fe, Ti)29-type structure. Substitution of Gd for Nd leads to a contraction of unit-cell volume. That’s because the smaller atomic radius of the Gd atom compared wit Nd .The Curie temperature Tc of (Nd1-xGdx)Fe27.31Ti1.69 compounds increases monotonically with increasing Gd content. We think it’s due to the Gd-Gd exhange interaction. Saturation magnetization Ms and spin reorientation temperature Tsr of(Nd1-xGdx)Fe27.31Ti1.69 compounds decrease with increasing Gd content. As temperature falls from room temperature to 5K, a spin reorientation from easy plane to the easy cone occurs for (Nd1-xGdx)Fe27.31Ti1.69 compounds.4. To find out the change of magnetocrystalline anisotropy for Er substitute Nd in Nd3(Fe, Ti)29 , (Nd1-xErx)Fe27.31Ti1.69 compounds were investigated by XRD and VSM and magnetic measurements. Substitution of Er for Nd does not lead to a change of crystal structure, All compounds with x in the range of x≤0.5 crystallize in Nd3(Fe, Ti)29-type structure. As temperature decreases from room temperature to 5K, a spin reorientation from easy plane to the easy cone occurs for (Nd1-xErx)Fe27.31Ti1.69 compounds.
2012年5月31日星期四
Synthesis, Structural Characterization and Catalytic Activity of Anionic Lanthanide Carbon-bridged Bis(Phenolate) Complexes
Synthesis, Structural Characterization and Catalytic Activity of Anionic Lanthanide Carbon-bridged Bis(Phenolate) Complexes
A series of anionic lanthanide complexes supported by carbon-bridged bis(phenolate)ligands were synthesized and structurally characterized, and their catalytic activity for the polymerization of e-caprolactone was tested. At the same time, the amido and aryloxo lanthanide complexes based onβ-diketiminate were synthesized, it was found that the corresponding lanthanide diamido complexes were efficient initiators for the polymerization ofε-caprolactone and lactide.1. Reactions of anhydrous LnCl3 with Li2MBMP in a 1:2 molar ratio in THF afforded the anionic lanthanide complexes[(THF)2Sm(MBMP)2][Li(THF)4](1) and[(THF)Yb(MBMP)2Li(THF)2](2), which Block Neodymium magnets were characterized by elemental analysis and IR spectra, X-ray single crystal analysis revealed 1 was an"ate" complex with a coordination number of 6 for Sm atom, while 2 was a bimetallic complex and in which Yb and Li were linked by two aryloxo groups, the coordination number of Yb was 5.2. Reaction of anhydrous LaCl3 with Na2MBMP in a 1:2 molar ratio in THF produced the anionic lanthanum complex[(THF)2La(MBMP)2Na(THF)2](3), 3 was characterized by elemental analysis, ER spectrum and X-ray single crystal diffraction.3. Reactions of anhydrous LnCl3 with K2MBMP in a 1:2 molar ratio in THF obtained the anionic lanthanide complexes[[La(THF)2]2(MBMP)4K}K(THF)6(4),[Nd2(MBMP)4K2(THF)2](5),[(THF)2Sm(MBMP)2K(THF)2](6), and[(THF)2Yb(MBMP)2K(THF)3](7).
All of the complexes were characterized by elemental analysis and IR spectra. Single crystal structure determination showed 4 was an"ate" complex and in the anionic segment of which two anion cores were linked by the K cation. While complex 5 demonstrated a binuclear structure in the solid state and in which two Nd atoms were linked by two bis(aryloxide) ligands, two K cations were located in two outer bis(phenolate) ligands. Complexes 6 and 7 were isostructural. http://www.999magnet.com/ Their structures are different from that of complexes 4 and 5, but are same as that of the corresponding anionic complexes containing sodium cation. 4. Complexes 1-7 can be used as single component catalysts to initiate the ring-opening polymerization ofε-caprolactone with moderate activity. In the presence of 1 equivalent of isopropanol, complexes 1-7 can catalyze the same polymerization in a controlled manner.5. Reaction of[{(2,6-Me2C6H3)NC(Me)}2CH]SmCl2(THF)2 with LiNPh2 in a 1:2 molar ratio in THF, after workup, afforded the diphenylamido complex[{(2,6-Me2C6H3)NC(Me)}2CH]Sm(NPh2)2(THF)(8) in high yield, which was characterization by elemental analysis and IR spectrum. Complex 8 can initiate the polymerization ofε-caprolactone and L-Lactide in very high activity. Compared with 8, the known complex[{(2,6-iPr2C6H3)NC(Me)}2CH]Yb(NPh2)2 showed lower activity.6. An unexpected complex[{(2,6-iPr2C6H3)NC(Me)}2CH]Yb(THF)(μ-Cl)3Yb(O-C6H3-2,6-Me2)[{(2,6-iPr2C6H3)N C(Me)}2CH](9) was synthesized by the reaction of[{(2,6-iPr2C6H3)NC(Me)}2CH]YbCl2(THF)2 with sodium 2,6-di-methylphenoxide in THF in a 1:1 molar ratio, which was characterized by elemental analysis and IR spectrum. Crystal structure determination of 9 revealed that it has a binuclear structure, in which two Yb atoms were linked by a trichloro bridge, the aryloxo group was coordinated to one of the Yb atoms.
A series of anionic lanthanide complexes supported by carbon-bridged bis(phenolate)ligands were synthesized and structurally characterized, and their catalytic activity for the polymerization of e-caprolactone was tested. At the same time, the amido and aryloxo lanthanide complexes based onβ-diketiminate were synthesized, it was found that the corresponding lanthanide diamido complexes were efficient initiators for the polymerization ofε-caprolactone and lactide.1. Reactions of anhydrous LnCl3 with Li2MBMP in a 1:2 molar ratio in THF afforded the anionic lanthanide complexes[(THF)2Sm(MBMP)2][Li(THF)4](1) and[(THF)Yb(MBMP)2Li(THF)2](2), which Block Neodymium magnets were characterized by elemental analysis and IR spectra, X-ray single crystal analysis revealed 1 was an"ate" complex with a coordination number of 6 for Sm atom, while 2 was a bimetallic complex and in which Yb and Li were linked by two aryloxo groups, the coordination number of Yb was 5.2. Reaction of anhydrous LaCl3 with Na2MBMP in a 1:2 molar ratio in THF produced the anionic lanthanum complex[(THF)2La(MBMP)2Na(THF)2](3), 3 was characterized by elemental analysis, ER spectrum and X-ray single crystal diffraction.3. Reactions of anhydrous LnCl3 with K2MBMP in a 1:2 molar ratio in THF obtained the anionic lanthanide complexes[[La(THF)2]2(MBMP)4K}K(THF)6(4),[Nd2(MBMP)4K2(THF)2](5),[(THF)2Sm(MBMP)2K(THF)2](6), and[(THF)2Yb(MBMP)2K(THF)3](7).
All of the complexes were characterized by elemental analysis and IR spectra. Single crystal structure determination showed 4 was an"ate" complex and in the anionic segment of which two anion cores were linked by the K cation. While complex 5 demonstrated a binuclear structure in the solid state and in which two Nd atoms were linked by two bis(aryloxide) ligands, two K cations were located in two outer bis(phenolate) ligands. Complexes 6 and 7 were isostructural. http://www.999magnet.com/ Their structures are different from that of complexes 4 and 5, but are same as that of the corresponding anionic complexes containing sodium cation. 4. Complexes 1-7 can be used as single component catalysts to initiate the ring-opening polymerization ofε-caprolactone with moderate activity. In the presence of 1 equivalent of isopropanol, complexes 1-7 can catalyze the same polymerization in a controlled manner.5. Reaction of[{(2,6-Me2C6H3)NC(Me)}2CH]SmCl2(THF)2 with LiNPh2 in a 1:2 molar ratio in THF, after workup, afforded the diphenylamido complex[{(2,6-Me2C6H3)NC(Me)}2CH]Sm(NPh2)2(THF)(8) in high yield, which was characterization by elemental analysis and IR spectrum. Complex 8 can initiate the polymerization ofε-caprolactone and L-Lactide in very high activity. Compared with 8, the known complex[{(2,6-iPr2C6H3)NC(Me)}2CH]Yb(NPh2)2 showed lower activity.6. An unexpected complex[{(2,6-iPr2C6H3)NC(Me)}2CH]Yb(THF)(μ-Cl)3Yb(O-C6H3-2,6-Me2)[{(2,6-iPr2C6H3)N C(Me)}2CH](9) was synthesized by the reaction of[{(2,6-iPr2C6H3)NC(Me)}2CH]YbCl2(THF)2 with sodium 2,6-di-methylphenoxide in THF in a 1:1 molar ratio, which was characterized by elemental analysis and IR spectrum. Crystal structure determination of 9 revealed that it has a binuclear structure, in which two Yb atoms were linked by a trichloro bridge, the aryloxo group was coordinated to one of the Yb atoms.
The Effect of Nd (Y) on Microstructure and Mechanical Properties of Mg-Zn Alloys
The Effect of Nd (Y) on Microstructure and Mechanical Properties of Mg-Zn Alloys
Wrought magnesium is noted to have a higher strength and ductility than cast magnesium. To research the good properties for magnesium alloys contained RE, in the present research Nd and Y respectively is odded to the Mg-5wt%Zn base alloys to produce as-cast and as-extruded(hot-extruded, extruded ratio is 17.5:1) alloys with different composition. This paper investigates the effect of RE elements and processing methods on microstructure and mechanical properties Special shape NdFeB magnets and discusses the strengthening mechanism.The results show that Nd addition on Mg-5wt%Zn magnesium alloy refine the grain; especially, when content of Nd is 3wt% the grains are the most finest. When Mg-5wt%Zn-(1-5)wt%Nd alloy is extruded at 330±10℃, the grain refined obviously.
Comparing to as-cast alloy of the same composition, the size of grains of hot-extruded alloy is finer, with the increase of percentage of Nd, and the longitudinal linear of microstructure is more obvious. Moreover, when hot-extruded Mg-5wt%Zn magnesium alloy, content of Nd is 3wt%, the ultimate tensile strength is 330.1MPa; and yield strength is 294.8MPa; the elongation is 9.84% at room temperature. The ultimate tensile strength is 248.4MPa; and yield strength is 203.4MPa; the elongation is 34.16% at 150℃. The ultimate tensile strength is 219.4MPa; and yield strength is 191.5MPa; the elongation is 42.6% at 200℃. The research on the microstructure and tensile properties of as-extruded Mg-5wt%Zn-(1-5)wt%Nd alloys reveals the alloys are not sensitive to aging treatment and the microstructure and the tensile properties have no obviously change. So the heat treatment is not necessary for this series of magnesium alloy. In addition, the effect of Nd and Y on the Mg-5wt%Zn alloy is almost the same.Discussion shows that RE addition and extruded treatment have huge effects on tensile properties of Mg-5wt%Zn alloy. They can refine grain and purify the grain boundary, which can http://www.999magnet.com/ improve the strength and ductility of alloys. Fracture surface analyses reveal that at low temperature, cleavage surface and tearing ridge of as-cast alloy, which was taken as typical brittle fracture features, could be seen on fracture surfaces. With increasing test temperature, brittle features decreased, while ductile ones increased. At elevated temperatures, cleavage surface was replaced by large amount of homogeneously distributed dimples.
Wrought magnesium is noted to have a higher strength and ductility than cast magnesium. To research the good properties for magnesium alloys contained RE, in the present research Nd and Y respectively is odded to the Mg-5wt%Zn base alloys to produce as-cast and as-extruded(hot-extruded, extruded ratio is 17.5:1) alloys with different composition. This paper investigates the effect of RE elements and processing methods on microstructure and mechanical properties Special shape NdFeB magnets and discusses the strengthening mechanism.The results show that Nd addition on Mg-5wt%Zn magnesium alloy refine the grain; especially, when content of Nd is 3wt% the grains are the most finest. When Mg-5wt%Zn-(1-5)wt%Nd alloy is extruded at 330±10℃, the grain refined obviously.
Comparing to as-cast alloy of the same composition, the size of grains of hot-extruded alloy is finer, with the increase of percentage of Nd, and the longitudinal linear of microstructure is more obvious. Moreover, when hot-extruded Mg-5wt%Zn magnesium alloy, content of Nd is 3wt%, the ultimate tensile strength is 330.1MPa; and yield strength is 294.8MPa; the elongation is 9.84% at room temperature. The ultimate tensile strength is 248.4MPa; and yield strength is 203.4MPa; the elongation is 34.16% at 150℃. The ultimate tensile strength is 219.4MPa; and yield strength is 191.5MPa; the elongation is 42.6% at 200℃. The research on the microstructure and tensile properties of as-extruded Mg-5wt%Zn-(1-5)wt%Nd alloys reveals the alloys are not sensitive to aging treatment and the microstructure and the tensile properties have no obviously change. So the heat treatment is not necessary for this series of magnesium alloy. In addition, the effect of Nd and Y on the Mg-5wt%Zn alloy is almost the same.Discussion shows that RE addition and extruded treatment have huge effects on tensile properties of Mg-5wt%Zn alloy. They can refine grain and purify the grain boundary, which can http://www.999magnet.com/ improve the strength and ductility of alloys. Fracture surface analyses reveal that at low temperature, cleavage surface and tearing ridge of as-cast alloy, which was taken as typical brittle fracture features, could be seen on fracture surfaces. With increasing test temperature, brittle features decreased, while ductile ones increased. At elevated temperatures, cleavage surface was replaced by large amount of homogeneously distributed dimples.
Chronology and Geochemistry of Late Mesozoic Volcanic Rocks in Eastern Jilin and Heilongjiang Provinces
Chronology and Geochemistry of Late Mesozoic Volcanic Rocks in Eastern Jilin and Heilongjiang Provinces
Detailed studies of chronology, petrology and geochemistry are carried out for the volcanic rocks from Suifenhe, Jingouling, and Tuntianying formations in eastern Jilin and Heilongjiang provinces in order to reveal their formation time and tectonic setting as well as the lithospheric evolution of northeast China in the late Mesozoic.1 Rock associations and geochemistry of late Mesozoic volcanic rocks in eastern Jilin and Heilongjiang provincesLate Mesozoic volcanic rocks in eastern Jilin and Heilongjiang provinces are mainly composed of basalt, basaltic andesite, andesite and dacite besides some basaltic trachyandesite and trachydacite from Tuntianying formation.They have SiO2 contents of 47.69%～65.47%, Al2O3 contents of 15.55%～18.76%, and are characterized by enrichment in Magnetic lifter magnesium (Mg#=45～53) and sodium (Na2O/K2O=1.49～3.63). Their K60 values range from 0.85 to 2.57. Plots of SiO2 against other major oxides show broadly negative correlations with TiO2, Fe2O3, MgO, CaO, and P2O5, and positive correlations with Na2O and K2O, while Al2O3 increase firstly and then decrease with the increase of SiO2 contents. They belong to subalkaline series and show a calc-alkaline evolutionary trend, most of them are plotted within (medium-K) calc-alkaline series in SiO2 vs. K2O diagram. Their total rare earth element contents (ΣREE) are between 94.17ppm and 142.32ppm. Their (La/Yb)N ratios andδEu values range from 3.20 to 18.90 and from 0.87 to 1.04, respectively. With the increase of SiO2 contents, the light rare earth element (LREE) abundances increase, whereas heavy rare earth element (HREE) abundances decrease.
On the chondrite-normalized REE diagram, the late Mesozoic volcanic rocks from eastern Jilin and Heilongjiang provinces are characterized by enrichment in LREEs, depletion in HREEs, and minor negative Eu anomalies or no Eu anomalies.On the primitive mantle-normalized spider diagram, all the samples display enrichment in large ion lithophile elements (LILEs, e.g., Rb, Ba, Th, U and K ), and LREEs, depletion in high field strength elements (HFSEs, e.g., Nb, Ta, Ti), which is similar to Andean arc volcanic rocks.Late Mesozoic volcanic rocks in eastern Jilin and Heilongjiang provinces have 87Sr/86Sr ratios of 0.704249～0.706130 and 143Nd/144Nd ratios of 0.512596～0.512815, while their initial 87Sr/86Sr ratios (ISr) andεNd(t) values are from 0.7041 to 0.7057 and from 0.40 to 4.11, respectively. Their SiO2 contents show broadly positive correlations with 87Sr/86Sr ratios and ISr values, and negative correlations with 143Nd/144Nd ratios andεNd(t) values.2 Chronology of late Mesozoic volcanic rocks in eastern Jilin and Heilongjiang provincesLA-ICPMS zircon U-Pb dating results http://www.999magnet.com/ indicate that volcanic rocks from Suifenhe formation, Jingouling formation, and Tuntianying formation formed at 105.5～93.2Ma, 106.6±2.1Ma, 97.3±1.4Ma, and 88.2±1.4Ma, respectively, i.e., from the late stage of Early Cretaceous to Late Cretaceous. This magmatic activity is consisitent with the time of alkaline basaltic magmatism occurred in the intracontinent of eastern China such as Qingshankou formation basalts from the Songliao basin, Fuxin basalts in western Liaoning Province, Daxizhuang basalts in eastern Shandong Province, and Qujiatun basalts in eastern Liaoning Province. 3 Magmatic evolution and magmatic source of late Mesozoic volcanic rocks in eastern Jilin and Heilongjing provincesThe existences of phenocrysts such as olivine, pyroxene, amphibole, and plagioclase in the late Mesozoic volcanic rocks suggest these minerals experience fractional crystallization during magmatic evolution, which is also proved by the linear correlation between SiO2 and other major oxides and trace elements.
The linear relationships between ISr, andεNd(t) values and SiO2 contents imply that the contamination of crustal materials might be involved in magmatic evolution. Therefore, mineral fractional crystallization and assimilation of crustal materials (AFC) are the dominant mechanism to control magmatic evolution.All the samples possess low ISr values, postiveεNd(t) values, and young TDM , implying a juvenile depleted magmatic source. Geochemical characteristics of major elements and trace elements suggest that depletion of HFSEs such as Nb and Ta, can not be explained by residue of minerals enriched in HFSEs in magmatic source or by simple contaminations of crustal materials. In the Rb/Y vs. Nb/Y diagram and Nb/Zr vs. Th/Zr diagram, these samples exhibit variation of fluid-related metasomatism. Therefore, it is suggested that the parental magma could be derived from partial melting of the mantle wedge metasomatized by subduction-related fluids.4 Tectonic setting of late Mesozoic volcanic rocks in eastern Jilin and Heilongjing provincesThe basalt-basaltic andesite-andesite-dacite association for the late Mesozoic volcanic rocks in eastern Jilin and Heilongjing is similar to those from active continental margins (e.g., Andes), suggesting that they were formed in active continental margin setting.The REE and trace element geochemical data for the late Mesozoic volcanic rocks display the geochemical characteristics of arc volcanic rocks (e.g., Ba/Nb vs. La/Nb diagram and Th-Hf/3-Ta ternary diagram). Taken together with rock association, it is proposed that the late Mesozoic volcanic rocks from eastern Jilin and Heilongjiang provinces were formed under active continental margin setting.Late Mesozoic magmatic activity in Magnetic lifter eastern Jilin and Heilongjiang provinces is coeval to the change of subduction angle of the Izanagi Plate beneath Eurasia continent (from NNW to near NW) and its subsequent NW subduction. Therefore, its genesis should be related to the subduction of Izanagi Plate, i.e., its oblique subduction against the Eurasia continent led to the formation of late Mesozoic volcanic rocks in eastern Jilin and Heilongjiang province with affinities of active continental margin.
Detailed studies of chronology, petrology and geochemistry are carried out for the volcanic rocks from Suifenhe, Jingouling, and Tuntianying formations in eastern Jilin and Heilongjiang provinces in order to reveal their formation time and tectonic setting as well as the lithospheric evolution of northeast China in the late Mesozoic.1 Rock associations and geochemistry of late Mesozoic volcanic rocks in eastern Jilin and Heilongjiang provincesLate Mesozoic volcanic rocks in eastern Jilin and Heilongjiang provinces are mainly composed of basalt, basaltic andesite, andesite and dacite besides some basaltic trachyandesite and trachydacite from Tuntianying formation.They have SiO2 contents of 47.69%～65.47%, Al2O3 contents of 15.55%～18.76%, and are characterized by enrichment in Magnetic lifter magnesium (Mg#=45～53) and sodium (Na2O/K2O=1.49～3.63). Their K60 values range from 0.85 to 2.57. Plots of SiO2 against other major oxides show broadly negative correlations with TiO2, Fe2O3, MgO, CaO, and P2O5, and positive correlations with Na2O and K2O, while Al2O3 increase firstly and then decrease with the increase of SiO2 contents. They belong to subalkaline series and show a calc-alkaline evolutionary trend, most of them are plotted within (medium-K) calc-alkaline series in SiO2 vs. K2O diagram. Their total rare earth element contents (ΣREE) are between 94.17ppm and 142.32ppm. Their (La/Yb)N ratios andδEu values range from 3.20 to 18.90 and from 0.87 to 1.04, respectively. With the increase of SiO2 contents, the light rare earth element (LREE) abundances increase, whereas heavy rare earth element (HREE) abundances decrease.
On the chondrite-normalized REE diagram, the late Mesozoic volcanic rocks from eastern Jilin and Heilongjiang provinces are characterized by enrichment in LREEs, depletion in HREEs, and minor negative Eu anomalies or no Eu anomalies.On the primitive mantle-normalized spider diagram, all the samples display enrichment in large ion lithophile elements (LILEs, e.g., Rb, Ba, Th, U and K ), and LREEs, depletion in high field strength elements (HFSEs, e.g., Nb, Ta, Ti), which is similar to Andean arc volcanic rocks.Late Mesozoic volcanic rocks in eastern Jilin and Heilongjiang provinces have 87Sr/86Sr ratios of 0.704249～0.706130 and 143Nd/144Nd ratios of 0.512596～0.512815, while their initial 87Sr/86Sr ratios (ISr) andεNd(t) values are from 0.7041 to 0.7057 and from 0.40 to 4.11, respectively. Their SiO2 contents show broadly positive correlations with 87Sr/86Sr ratios and ISr values, and negative correlations with 143Nd/144Nd ratios andεNd(t) values.2 Chronology of late Mesozoic volcanic rocks in eastern Jilin and Heilongjiang provincesLA-ICPMS zircon U-Pb dating results http://www.999magnet.com/ indicate that volcanic rocks from Suifenhe formation, Jingouling formation, and Tuntianying formation formed at 105.5～93.2Ma, 106.6±2.1Ma, 97.3±1.4Ma, and 88.2±1.4Ma, respectively, i.e., from the late stage of Early Cretaceous to Late Cretaceous. This magmatic activity is consisitent with the time of alkaline basaltic magmatism occurred in the intracontinent of eastern China such as Qingshankou formation basalts from the Songliao basin, Fuxin basalts in western Liaoning Province, Daxizhuang basalts in eastern Shandong Province, and Qujiatun basalts in eastern Liaoning Province. 3 Magmatic evolution and magmatic source of late Mesozoic volcanic rocks in eastern Jilin and Heilongjing provincesThe existences of phenocrysts such as olivine, pyroxene, amphibole, and plagioclase in the late Mesozoic volcanic rocks suggest these minerals experience fractional crystallization during magmatic evolution, which is also proved by the linear correlation between SiO2 and other major oxides and trace elements.
The linear relationships between ISr, andεNd(t) values and SiO2 contents imply that the contamination of crustal materials might be involved in magmatic evolution. Therefore, mineral fractional crystallization and assimilation of crustal materials (AFC) are the dominant mechanism to control magmatic evolution.All the samples possess low ISr values, postiveεNd(t) values, and young TDM , implying a juvenile depleted magmatic source. Geochemical characteristics of major elements and trace elements suggest that depletion of HFSEs such as Nb and Ta, can not be explained by residue of minerals enriched in HFSEs in magmatic source or by simple contaminations of crustal materials. In the Rb/Y vs. Nb/Y diagram and Nb/Zr vs. Th/Zr diagram, these samples exhibit variation of fluid-related metasomatism. Therefore, it is suggested that the parental magma could be derived from partial melting of the mantle wedge metasomatized by subduction-related fluids.4 Tectonic setting of late Mesozoic volcanic rocks in eastern Jilin and Heilongjing provincesThe basalt-basaltic andesite-andesite-dacite association for the late Mesozoic volcanic rocks in eastern Jilin and Heilongjing is similar to those from active continental margins (e.g., Andes), suggesting that they were formed in active continental margin setting.The REE and trace element geochemical data for the late Mesozoic volcanic rocks display the geochemical characteristics of arc volcanic rocks (e.g., Ba/Nb vs. La/Nb diagram and Th-Hf/3-Ta ternary diagram). Taken together with rock association, it is proposed that the late Mesozoic volcanic rocks from eastern Jilin and Heilongjiang provinces were formed under active continental margin setting.Late Mesozoic magmatic activity in Magnetic lifter eastern Jilin and Heilongjiang provinces is coeval to the change of subduction angle of the Izanagi Plate beneath Eurasia continent (from NNW to near NW) and its subsequent NW subduction. Therefore, its genesis should be related to the subduction of Izanagi Plate, i.e., its oblique subduction against the Eurasia continent led to the formation of late Mesozoic volcanic rocks in eastern Jilin and Heilongjiang province with affinities of active continental margin.
The Fractal Research of the Interface and the Microstructure Properties of the Vacuum Fusion Sintering Nickel-base Alloy Coating with Rare Earth Joined
The Fractal Research of the Interface and the Microstructure Properties of the Vacuum Fusion Sintering Nickel-base Alloy Coating with Rare Earth Joined
The interface property of the vacuum fusion sintering Ni-base alloy coating has been researched by the fractal method.Through the fractal analysis to the alloy coating interface morphology,the relationship between the micro-hardness、diffusion coefficient、thermal fatigue property and the fractal has been constructed.The Ni-base RE alloy coating and Ni-base-WC composite coating were obtained by the technique of vacuum fusion sintering on the 45 steel.The Neodymium Magnets interface morphology and the micro-structure symbol of the section were analysised with the method of SEM.Also the micro-hardness destruction values in the two sides of the vertical section were measured by the micro sclerometer. The values were analysised.Use the EDS ,the contents of the certain element in the two sides of the coating were measured, then the diffusion coefficient calculation equation was deduced,which could calculate the element diffusion coefficient value in the certain depth.To the thermal fatigue property,there were some analysis in this paper.The interface and surface of the coating are nonlinear,belong to random fractal,also the geometrical shape with the certain fractal dimension.
Different coatings have different interface morphology, the fractal dimension of the certain coating vertical section with the fractal was calculated.For the fractal dimension show the "random degree" of the fractal graph ,the certain fractal dimension value corresponds the certain alloy coating.In this paper, the preparation materials were vacuum fusion sintering NiCrBSi-RE alloy coating which the different content and sort were added and the composite coating with http://www.999magnet.com/ different WC content. The relationship between the fractal dimension of the coating vertical section and the distribution of the micro-hardness、thermal fatigue property、micro-structure.Then the aim that the fractal dimension symbolize the coating macro-property was gotten which would take a new method to the material analysis.According to the research result,the fractal dimension values correspond to the different microstructure、the micro-hardness distribution value、the thermal fatigue property.Generally,the fractal dimensions of the alloy coatings with RE are larger than the ones of the alloy coating without RE addition,the micro-hardness distribution values are also higher.Comparing to the microstructure,the column-shape crystal areas were more obvious,the spherical pharse were more and the neddle phases lessened in the interface fusion areas of the alloy coating with RE.To the composite coating which the http://www.999magnet.com/ WC was added,the WC appeared with the spherical dispersion which improved the comprehensive property of the coating.Corresponding to the fractal dimension,the values became higer.The alloy coatings which their fractal dimension values were larger than 1.77 had the better thermal fatigue property,while the ones less than 1.75,their thermal fatigue property were worse.
The interface property of the vacuum fusion sintering Ni-base alloy coating has been researched by the fractal method.Through the fractal analysis to the alloy coating interface morphology,the relationship between the micro-hardness、diffusion coefficient、thermal fatigue property and the fractal has been constructed.The Ni-base RE alloy coating and Ni-base-WC composite coating were obtained by the technique of vacuum fusion sintering on the 45 steel.The Neodymium Magnets interface morphology and the micro-structure symbol of the section were analysised with the method of SEM.Also the micro-hardness destruction values in the two sides of the vertical section were measured by the micro sclerometer. The values were analysised.Use the EDS ,the contents of the certain element in the two sides of the coating were measured, then the diffusion coefficient calculation equation was deduced,which could calculate the element diffusion coefficient value in the certain depth.To the thermal fatigue property,there were some analysis in this paper.The interface and surface of the coating are nonlinear,belong to random fractal,also the geometrical shape with the certain fractal dimension.
Different coatings have different interface morphology, the fractal dimension of the certain coating vertical section with the fractal was calculated.For the fractal dimension show the "random degree" of the fractal graph ,the certain fractal dimension value corresponds the certain alloy coating.In this paper, the preparation materials were vacuum fusion sintering NiCrBSi-RE alloy coating which the different content and sort were added and the composite coating with http://www.999magnet.com/ different WC content. The relationship between the fractal dimension of the coating vertical section and the distribution of the micro-hardness、thermal fatigue property、micro-structure.Then the aim that the fractal dimension symbolize the coating macro-property was gotten which would take a new method to the material analysis.According to the research result,the fractal dimension values correspond to the different microstructure、the micro-hardness distribution value、the thermal fatigue property.Generally,the fractal dimensions of the alloy coatings with RE are larger than the ones of the alloy coating without RE addition,the micro-hardness distribution values are also higher.Comparing to the microstructure,the column-shape crystal areas were more obvious,the spherical pharse were more and the neddle phases lessened in the interface fusion areas of the alloy coating with RE.To the composite coating which the http://www.999magnet.com/ WC was added,the WC appeared with the spherical dispersion which improved the comprehensive property of the coating.Corresponding to the fractal dimension,the values became higer.The alloy coatings which their fractal dimension values were larger than 1.77 had the better thermal fatigue property,while the ones less than 1.75,their thermal fatigue property were worse.
2012年5月23日星期三
Studies on the Preparation and Luminescence Properties of Rare-earth Nanomaterials Applied to Luminescent Label
Studies on the Preparation and Luminescence Properties of Rare-earth Nanomaterials Applied to Luminescent Label
With rapid development of nanoscience and nanotechnology, many nanoparticles show
great academic and application values because of their unique physical and chemical
properties, especially optical and biological properties. Many investigators are trying to
develop various high sensitivity and selectivity detection methods and apparatuses,
based on unique properties of the nanoparticles. Nanoparticles as biological fluorescence
probe possess excellent optical properties, such as: a narrow, tunable, symmetric emission
spectrum and a broad, continuous excitation spectrum. They are also photo-chemically stable and they have fluorescence quantum yields and long fluorescence lifetime.
The high selectivity and sensitivity should be acquired when the nanoparticles are used to detect
the macromolecules.This dissertation reports on the Block neodymium magnet synthesis as well as the optical properties of
the nanomaterials prepared by different methods with controlled phases and morphologies. They
show potential application in luminescence labels. The results of this dissertation are summarized
as follows:Eu3+-doped LaF3 nanoparticles were prepared by a hydrothermal process at a low temperature.
Well-dispersed nanoparticles with an average size of 30nm and a hexagonal shape were synthesized.
In order to explore the optimal conditions to synthesis luminescent nanoparticles, we systematically
investigated the influences of reaction temperature, time, initial pH and proportion of reactants
on the morphology, size and luminescence of LaF3:Eu3+ nanoparticles. The luminescent properties
of LaF3:Eu3+ nanoparticles show that http://www.chinamagnets.biz/ fluorescent intensity of prepared samples without any
further calcinations is five times stronger and Eu3+-doped concentration is much higher than that of bulk materials prepared by high temperature
solid synthesis. Thus, the LaF3:Eu3+ nanoparticles have potential application to luminescent
label.Based on these results mentioned above, green-emitting LaF3:Ce,Tb phosphor nanoparticles were synthesized by a simple hydrothermal method.
Above all, the 更多还原
Preparation of Rare Earth Composite Nanoparticles and Their Application
Preparation of Rare Earth Composite Nanoparticles and Their Application
It is well-known that the complexes of Tb3+ and Eu3+ have excellent luminescence properties including larger stokes shift, narrow emission profiles and a long fluorescence lifetime. In addition, organic macromolecules feature favorable stability and convenient preparation. So we envisage that these kinds of composite nanoparticles can be used as the fluorescence probes for the determination of trace substance with good sensitivity and selectivity.In this paper, nano-Tb / acac and Eu / TTA have been successfully prepared. The nano-Tb / acac has been modified with AA and AM, respectively, and nano- Eu / TTA has been modified with AA under ultrasonic irradiation in strong magnets water solution. The functionalized nanoparticles are well stable in the water. All the nanoparticles have been characterized by Fluorescence spectra and TEM images. Based on the fluorescence quenching of Tb / acac / PAA by Vc, Tb / acac / PAM by Cr(Ⅵ)and Eu / TTA / PAA by DNA. We used them as fluorescence probes in the determination. Under the optimum conditions, linear calibration graph were obtained. The methods http://www.chinamagnets.biz/ in this paper proved to be simple, rapid, and specific, and the recovery and relative standard deriation are very satisfactory.
It is well-known that the complexes of Tb3+ and Eu3+ have excellent luminescence properties including larger stokes shift, narrow emission profiles and a long fluorescence lifetime. In addition, organic macromolecules feature favorable stability and convenient preparation. So we envisage that these kinds of composite nanoparticles can be used as the fluorescence probes for the determination of trace substance with good sensitivity and selectivity.In this paper, nano-Tb / acac and Eu / TTA have been successfully prepared. The nano-Tb / acac has been modified with AA and AM, respectively, and nano- Eu / TTA has been modified with AA under ultrasonic irradiation in strong magnets water solution. The functionalized nanoparticles are well stable in the water. All the nanoparticles have been characterized by Fluorescence spectra and TEM images. Based on the fluorescence quenching of Tb / acac / PAA by Vc, Tb / acac / PAM by Cr(Ⅵ)and Eu / TTA / PAA by DNA. We used them as fluorescence probes in the determination. Under the optimum conditions, linear calibration graph were obtained. The methods http://www.chinamagnets.biz/ in this paper proved to be simple, rapid, and specific, and the recovery and relative standard deriation are very satisfactory.
包头稀土高新区优化发展环境对策研究
包头稀土高新区优化发展环境对策研究
Environment is productivity. Environment is competitiveness. Good investment environment is a pivotal symbol to measure the ability of an area’s core competition and potential development. The core for further improving environment is to optimize the environment and raise it comprehensive competitiveness. The measure that Rare earth Hi-tech Zone(abbreviated as Hi-tech zone)uses mainly depends on the improvement of pioneering environment and offering excellent development conditions.At present, the 11th five year plan has just been devised. Hi-tech zone rare earth magnets guided by the 16th No.5 CPC meeting, in accordance with science development, has devised its 11th five year plan. "Plan for optimization of environment in Hi-tech zone" has been listed as specific project in the "
General plan of economic and social development in Hi-tech Zone" and put in an important position in the Hi-tech zone’s development strategy and emphasize by Administration committee of Hi-tech zone. So, the specific research in the optimization of environment of Hi-tech zone can offer feasible measures and suggestions and has an important meaning in http://www.chinamagnets.biz/ winning the competitiveness and "Second pioneering enterprises".The article mentioned developing environment includes environment in terms of infrastructure, mechanism, service, policies, laws and rules, markets, people and culture, safety, ecology, etc.. It’s an integration of components of politics, economy, society, culture, technology and nature etc.. Good environment is and embodiment of civilization of material, rare earth magnets politics and spirits.The emphasize of the article is the research optimization of environment in the Hi-tech zone as well as detailed measures and suggestions.The article is made of 4 parts. Part one, the basic information of national-level Hi-tech zone; Part two, the situation and analysis of Baotou rare earth Hi-tech zone; Part 3, Measures and suggestions of Baotou Hi-tech zone in the optimization of developing environment.
Environment is productivity. Environment is competitiveness. Good investment environment is a pivotal symbol to measure the ability of an area’s core competition and potential development. The core for further improving environment is to optimize the environment and raise it comprehensive competitiveness. The measure that Rare earth Hi-tech Zone(abbreviated as Hi-tech zone)uses mainly depends on the improvement of pioneering environment and offering excellent development conditions.At present, the 11th five year plan has just been devised. Hi-tech zone rare earth magnets guided by the 16th No.5 CPC meeting, in accordance with science development, has devised its 11th five year plan. "Plan for optimization of environment in Hi-tech zone" has been listed as specific project in the "
General plan of economic and social development in Hi-tech Zone" and put in an important position in the Hi-tech zone’s development strategy and emphasize by Administration committee of Hi-tech zone. So, the specific research in the optimization of environment of Hi-tech zone can offer feasible measures and suggestions and has an important meaning in http://www.chinamagnets.biz/ winning the competitiveness and "Second pioneering enterprises".The article mentioned developing environment includes environment in terms of infrastructure, mechanism, service, policies, laws and rules, markets, people and culture, safety, ecology, etc.. It’s an integration of components of politics, economy, society, culture, technology and nature etc.. Good environment is and embodiment of civilization of material, rare earth magnets politics and spirits.The emphasize of the article is the research optimization of environment in the Hi-tech zone as well as detailed measures and suggestions.The article is made of 4 parts. Part one, the basic information of national-level Hi-tech zone; Part two, the situation and analysis of Baotou rare earth Hi-tech zone; Part 3, Measures and suggestions of Baotou Hi-tech zone in the optimization of developing environment.
2012年5月17日星期四
Preparation and Properties of Aluminum Coating on NdFeB Magnet
Preparation and Properties of Aluminum Coating on NdFeB Magnet
A dense and adhesive aluminum coating was successfully electrodeposited on NdFeB rare earth alloy by using THF organic solvent electrolyte. Properties of Al coating were systematically investigated. It was found that aluminum coating could offer NdFeB rare earth alloy excellent protection, and better deposits could be obtained through controlling the electroplating variables, such as electrolyte compositon, current density and time. Effects of heat treatment on Al Alnico magnets coating were also studied in this paper.Cathode current efficiencies were almost above 90% in all electrodeposition experiment. No side reations were observed on the cathode surface. Current distribution on cathode was great, and uniform deposits could be electrodeposited on more complicated substrate. Energy consumption was acceptable in the electrolyte composion selected in this study when current density was below 4A/dm~2.Structural analysis of the deposits showed that it was pure aluminum. Morphological analysis of Al coating were investigated.
Better surface with even Al particles appeared when molar ration of AlCl3 and LiAlH4 was 3:1 and current density and electroplating time was in range of 2-4A/dm~2 and 30-60min respectively, and it did contributed to excellent properties of Al coatings. http://www.999magnet.com/ Properties of Al coating, such as thickness, hardness, adhesion and corrosion protection were tested in detail. The results showed the thickness of Al coating was in the range of 9-42μm. Thickness of Al coating (Electroplating rate) was propotional to the product of current density and current efficiencies. Microhardness increased slightly in the range of 45-80HV with the increaing of current density and electroplating time. Adhesion force of Al coating to the substrate was all above 40N, and there was a maximum in the curve of adhesion force to current density and electroplating time in range of current density 2-4A/dm~2 and electroplating time 30-60min respectively. Al coating improved the performance of NdFeB magnets in high temperature. Weight increase was much less than the increase of NdFeB magnets in the same situation. When Alnico magnets current density and electroplating time was 2-4A/dm~2 and 30-60min respectively, Al coating had less weight increase. Also, maximum of R_p values of Al coating in neutral 3.5%NaCl occurred with current density and electroplating time among 2-4A/dm~2 and 30-60min respectively. R_p values of Al coating were all above 2.5×10~4Ω·cm~2. Al coating offered a great corrosion protection for NdFeB magnetsAfter long time heat trement in high temperature, element diffusion occurred at the interface of Al layer and NdFeB rare earth alloy. The morphologies changed obviously, and little boundaries disappeared, but little cracks between big particles were kept down. The adhesion force decreased because the expanding of Al deposits disagreed with NdFeB rare earth alloy during heating. Corrosion resistance of Al coating didn’t improve after heat treatment.
A dense and adhesive aluminum coating was successfully electrodeposited on NdFeB rare earth alloy by using THF organic solvent electrolyte. Properties of Al coating were systematically investigated. It was found that aluminum coating could offer NdFeB rare earth alloy excellent protection, and better deposits could be obtained through controlling the electroplating variables, such as electrolyte compositon, current density and time. Effects of heat treatment on Al Alnico magnets coating were also studied in this paper.Cathode current efficiencies were almost above 90% in all electrodeposition experiment. No side reations were observed on the cathode surface. Current distribution on cathode was great, and uniform deposits could be electrodeposited on more complicated substrate. Energy consumption was acceptable in the electrolyte composion selected in this study when current density was below 4A/dm~2.Structural analysis of the deposits showed that it was pure aluminum. Morphological analysis of Al coating were investigated.
Better surface with even Al particles appeared when molar ration of AlCl3 and LiAlH4 was 3:1 and current density and electroplating time was in range of 2-4A/dm~2 and 30-60min respectively, and it did contributed to excellent properties of Al coatings. http://www.999magnet.com/ Properties of Al coating, such as thickness, hardness, adhesion and corrosion protection were tested in detail. The results showed the thickness of Al coating was in the range of 9-42μm. Thickness of Al coating (Electroplating rate) was propotional to the product of current density and current efficiencies. Microhardness increased slightly in the range of 45-80HV with the increaing of current density and electroplating time. Adhesion force of Al coating to the substrate was all above 40N, and there was a maximum in the curve of adhesion force to current density and electroplating time in range of current density 2-4A/dm~2 and electroplating time 30-60min respectively. Al coating improved the performance of NdFeB magnets in high temperature. Weight increase was much less than the increase of NdFeB magnets in the same situation. When Alnico magnets current density and electroplating time was 2-4A/dm~2 and 30-60min respectively, Al coating had less weight increase. Also, maximum of R_p values of Al coating in neutral 3.5%NaCl occurred with current density and electroplating time among 2-4A/dm~2 and 30-60min respectively. R_p values of Al coating were all above 2.5×10~4Ω·cm~2. Al coating offered a great corrosion protection for NdFeB magnetsAfter long time heat trement in high temperature, element diffusion occurred at the interface of Al layer and NdFeB rare earth alloy. The morphologies changed obviously, and little boundaries disappeared, but little cracks between big particles were kept down. The adhesion force decreased because the expanding of Al deposits disagreed with NdFeB rare earth alloy during heating. Corrosion resistance of Al coating didn’t improve after heat treatment.
Preparation and Performance of RE Molybdenum Carbide and Molybdenum Carbide
Preparation and Performance of RE Molybdenum Carbide and Molybdenum Carbide
Using ordinary water synthesize three B-type structure Anderson polyo-xometalate (NH4)3[XMo6O24H6]·7H2O (abbreviated as XMo6, X = Fe, Cr, Ni), X-ray diffraction (XRD), Thermo-gravimetric differential thermal analysis (TG-DTA) were used to test its structure, Thermal stability of the characterization.to preparate of molybdenum carbide and RE molybdenum carbide,using XMo6 (X = Fe, Cr, Ni) as a precursor, respectively, with methanol as Neodymium Magnets penetration agent or adding NdCl3, LaCl3, SmCl3, GdCl3 and mixed rare earth chloride as a penetration agent by RE-permeation at different temperature, And making a study on its structure, composition, morphology, valence and electrical properties, catalytic properties.
The results showed : RE: Nd, La, Sm, Gd infiltrated into the molybdenum carbide surface phase and bulk, with complex reaction, Generating a new rare-earth compounds RE LnxMoyC molybdenum carbide, the electric performance has been significantly improved. It has certain catalytic properties for anodes In DMFC.The result of XRD characterization : RE molybdenum carbide crystal structure was a single hexagonal close-packed (hcp)β-Mo2C structure. XPS http://www.999magnet.com/ and EDX test results show that the rare earth elements Nd, Gd, La, Sm has entered molybdenum carbide crystal phase. Their valence and molar percentage are La3+ (0.19%), Nd3+ (0.18%), Sm3+ (0.17%) and Gd3+ (0.16%). Molecular Formula abbreviation is LnxMoyC. TG-DTA analysis of thermal stability tests showed : LnxMoyC stability than the current industrial semiconductor and dielectric materials coated molybdenum carbide coating.
The GdxMoyC stability is also upgraded.The conductivity test’s results show : Mo2C : 1.025×102 S·cm-1, LnxMoyC : 4.692×103 S·cm-1, GdxMoyC: 2.002×103 S·cm-1. both higher than the current literature recorded the highest value of 1.025×102 S·cm-1 at Neodymium Magnets room temperature., the RE molybdenum carbide or molybdenum carbide conductive ,which the RE molybdenum carbide or molybdenum carbide were penetration on difference precursor, enhance with different rates; conductivity test at difference temperature shows that : LnxMoyC showed the metal character at 289 490 K, and there has been a significant semiconductor behaviorfrom 490550 K. Mo=C shown the semiconductor in certain temperature range, but is not obvious as LnxMoyC.In Direct Methanol Fuel Cell (DMFC) system, we tried to make a study on RE molybdenum carbide LnxMoyC electro-catalytic properties of electrochemical testing, at methanol oxidation potential of 0.8V, appeared strong oxidation peak. Note LnxMoyC/C shows it’s catalytic role. BET test result shows that LnxMoyC surface area is 40 m2, the size test analysis show that it’s particle size distribution is uneven. That is likely to affect the catalytic properties.
Using ordinary water synthesize three B-type structure Anderson polyo-xometalate (NH4)3[XMo6O24H6]·7H2O (abbreviated as XMo6, X = Fe, Cr, Ni), X-ray diffraction (XRD), Thermo-gravimetric differential thermal analysis (TG-DTA) were used to test its structure, Thermal stability of the characterization.to preparate of molybdenum carbide and RE molybdenum carbide,using XMo6 (X = Fe, Cr, Ni) as a precursor, respectively, with methanol as Neodymium Magnets penetration agent or adding NdCl3, LaCl3, SmCl3, GdCl3 and mixed rare earth chloride as a penetration agent by RE-permeation at different temperature, And making a study on its structure, composition, morphology, valence and electrical properties, catalytic properties.
The results showed : RE: Nd, La, Sm, Gd infiltrated into the molybdenum carbide surface phase and bulk, with complex reaction, Generating a new rare-earth compounds RE LnxMoyC molybdenum carbide, the electric performance has been significantly improved. It has certain catalytic properties for anodes In DMFC.The result of XRD characterization : RE molybdenum carbide crystal structure was a single hexagonal close-packed (hcp)β-Mo2C structure. XPS http://www.999magnet.com/ and EDX test results show that the rare earth elements Nd, Gd, La, Sm has entered molybdenum carbide crystal phase. Their valence and molar percentage are La3+ (0.19%), Nd3+ (0.18%), Sm3+ (0.17%) and Gd3+ (0.16%). Molecular Formula abbreviation is LnxMoyC. TG-DTA analysis of thermal stability tests showed : LnxMoyC stability than the current industrial semiconductor and dielectric materials coated molybdenum carbide coating.
The GdxMoyC stability is also upgraded.The conductivity test’s results show : Mo2C : 1.025×102 S·cm-1, LnxMoyC : 4.692×103 S·cm-1, GdxMoyC: 2.002×103 S·cm-1. both higher than the current literature recorded the highest value of 1.025×102 S·cm-1 at Neodymium Magnets room temperature., the RE molybdenum carbide or molybdenum carbide conductive ,which the RE molybdenum carbide or molybdenum carbide were penetration on difference precursor, enhance with different rates; conductivity test at difference temperature shows that : LnxMoyC showed the metal character at 289 490 K, and there has been a significant semiconductor behaviorfrom 490550 K. Mo=C shown the semiconductor in certain temperature range, but is not obvious as LnxMoyC.In Direct Methanol Fuel Cell (DMFC) system, we tried to make a study on RE molybdenum carbide LnxMoyC electro-catalytic properties of electrochemical testing, at methanol oxidation potential of 0.8V, appeared strong oxidation peak. Note LnxMoyC/C shows it’s catalytic role. BET test result shows that LnxMoyC surface area is 40 m2, the size test analysis show that it’s particle size distribution is uneven. That is likely to affect the catalytic properties.
The Construction of Amphiphillic Multifunctional Ligand and Thin Film-Controlled Synthesis of Nanosized Lanthanide Phosphors
The Construction of Amphiphillic Multifunctional Ligand and Thin Film-Controlled Synthesis of Nanosized Lanthanide Phosphors
On account of the energy match and energy transfer mechanism, relative researches were concentrated on constructing special ligand which possess sensitization, coordination ability and film-forming property, complexing the ligand with rare earth ions to obtain multifunctional lanthanide complexes precursors, and selecting proper condition in order to control the morphology and microstructures of the materials and improve their optical properties.In this paper, by designing special amphiphilic lanthanide complexes as precursors, we put forward a novel optimized synthesis of lanthanide luminescent materials. Firstly, the amphiphilic binary multifunctional lanthanide complexes were constructed by complexing rare earth ions with pre-designed amphiphillic long chain multifunctional ligand.
Then, the amphiphilic ternary lanthanide complexes Neodymium Magnets were synthesized by introducing some proper assistant materials into the as-derived binary amphiphilic lanthanide complexes. At last, by selecting the as-derived binary amphiphilic lanthanide complexes and ternary lanthanide complexes with multiple function as the precursors, respectively, both solid luminescent materials and lanthanide complexes LB film have been successfully synthesized. The researches were concentrated on constructing ligand with multiple function and studying the influence of pre-designed multifunctional amphiphilc precursors on the morphology and microstructures of the products. We further explored the feasibility of its application in the field of luminescent materials.Based on the above ideas, we achieved the following results: Firstly, binary amphiphilic multifunctional long chain lanthanide complexes with mono-L cis-butene dicarboxylate (L = hexadecyl, octadecyl and eicosyl), i.e. MAH, MAO and MAE, respectively, were constructed. The corresponding ternary lanthanide (Eu3+, Tb3+) complexes with the pre-designed monoester ligands and nitrogen heterocyclic ligands (2,2’-bipyridyl (bipy) Neodymium Magnets and 1,10-phenanthroline (phen)) have been successfully synthesized and characterized.
The photophysical properties of ternary lanthanide complexes have been studied with ultraviolet spectra, phosphorescence spectra, excitation and emission spectra and luminescent lifetimes. Energy match and energy transfer between the triplet state of ligands and lanthanide ions were examined. It also reveals that the multiply functional ligand are suitable for those of the excited states of the lanthanide ions, especially for luminescent Eu3+ ion and Tb3+ ion. Secondly, using amphiphilic binary multifunctional long chain lanthanide ions complexes as precursors, we http://www.999magnet.com/ have synthesized three kinds of nanoparticles after calcinating at proper temperatures. They are Y2O3:Eu3+/GdXY2-XO3: Eu3+, CeO2 and ZnO materials, respectively. The morphology and microstructures of all the samples were characterized by Scanning electronic microscope (SEM), Transmission electron microscopic (TEM) and X-ray diffraction (XRD), respectively. The photophysical properties of them were studied in detail with IR spectra, ultraviolet absorption spectra, luminescent excitation and emission spectra, respectively. We further studied the influence of amphiphilc precursor molecules on the morphology, microstructures and photophysical properties of our products; Thirdly, it is the first time to Neodymium Magnets prepare ternary lanthanide complexes with long chain MAH/MAO and 1,10-Phenanthroline by using Langmuir-Blodgett (LB) technique. The AFM study showed that he LB film were mainly covered by a large amount of chains like structure probably caused by long chain molecules.
On account of the energy match and energy transfer mechanism, relative researches were concentrated on constructing special ligand which possess sensitization, coordination ability and film-forming property, complexing the ligand with rare earth ions to obtain multifunctional lanthanide complexes precursors, and selecting proper condition in order to control the morphology and microstructures of the materials and improve their optical properties.In this paper, by designing special amphiphilic lanthanide complexes as precursors, we put forward a novel optimized synthesis of lanthanide luminescent materials. Firstly, the amphiphilic binary multifunctional lanthanide complexes were constructed by complexing rare earth ions with pre-designed amphiphillic long chain multifunctional ligand.
Then, the amphiphilic ternary lanthanide complexes Neodymium Magnets were synthesized by introducing some proper assistant materials into the as-derived binary amphiphilic lanthanide complexes. At last, by selecting the as-derived binary amphiphilic lanthanide complexes and ternary lanthanide complexes with multiple function as the precursors, respectively, both solid luminescent materials and lanthanide complexes LB film have been successfully synthesized. The researches were concentrated on constructing ligand with multiple function and studying the influence of pre-designed multifunctional amphiphilc precursors on the morphology and microstructures of the products. We further explored the feasibility of its application in the field of luminescent materials.Based on the above ideas, we achieved the following results: Firstly, binary amphiphilic multifunctional long chain lanthanide complexes with mono-L cis-butene dicarboxylate (L = hexadecyl, octadecyl and eicosyl), i.e. MAH, MAO and MAE, respectively, were constructed. The corresponding ternary lanthanide (Eu3+, Tb3+) complexes with the pre-designed monoester ligands and nitrogen heterocyclic ligands (2,2’-bipyridyl (bipy) Neodymium Magnets and 1,10-phenanthroline (phen)) have been successfully synthesized and characterized.
The photophysical properties of ternary lanthanide complexes have been studied with ultraviolet spectra, phosphorescence spectra, excitation and emission spectra and luminescent lifetimes. Energy match and energy transfer between the triplet state of ligands and lanthanide ions were examined. It also reveals that the multiply functional ligand are suitable for those of the excited states of the lanthanide ions, especially for luminescent Eu3+ ion and Tb3+ ion. Secondly, using amphiphilic binary multifunctional long chain lanthanide ions complexes as precursors, we http://www.999magnet.com/ have synthesized three kinds of nanoparticles after calcinating at proper temperatures. They are Y2O3:Eu3+/GdXY2-XO3: Eu3+, CeO2 and ZnO materials, respectively. The morphology and microstructures of all the samples were characterized by Scanning electronic microscope (SEM), Transmission electron microscopic (TEM) and X-ray diffraction (XRD), respectively. The photophysical properties of them were studied in detail with IR spectra, ultraviolet absorption spectra, luminescent excitation and emission spectra, respectively. We further studied the influence of amphiphilc precursor molecules on the morphology, microstructures and photophysical properties of our products; Thirdly, it is the first time to Neodymium Magnets prepare ternary lanthanide complexes with long chain MAH/MAO and 1,10-Phenanthroline by using Langmuir-Blodgett (LB) technique. The AFM study showed that he LB film were mainly covered by a large amount of chains like structure probably caused by long chain molecules.
新型吡啶衍生物及其稀土配合物的合成、表征与荧光性能研究
新型吡啶衍生物及其稀土配合物的合成、表征与荧光性能研究
Pyridine-2,6-dicarboxylic is the best sensitizer of the lanthanide (Tb3+, Eu3+ ions) than salicylic , phenanthroline. And the lanthanide complexes with-β-diketone-kind ligands are of high ability of UV-vis exicitation fluorescence, and the ligands make rare earth ions emit strong characteristic fluorescence by organic ligands’strong UV-vis absorbance and efficienct energy-transfer between the ligands and ions. Therefore,designing and synthesizing novel pyridine-2,6-dicarboxylic derivatives, especially di-β-diketone-kind compounds and their derivatives, is of great importance for searching and developing novel sensitizers for rare earth ions with pyridine-2,6-dicarboxylic as a starting material,and designing the structures of ligands is also a key point to discover new rare-earth ions fluorescent sensitizersIn this paper , a list of di-β-diketone organic ligands and their di-pyrazole derivatives which magnet lifter were not reported by references so far, and have big n-conjugated system were designed,and a novel di-β-diketone organic intermediate 2,6-bisbenzoylactyl pyridine (L7) was synthesized by esterification and Claisen Condensation reaction using pyridine -2,6-dicarboxylic dacid which is a better fluorescent sensitizer as starting material and its two derivatives 2,6-di[(3-pyrazolyl)-5-phenyl] pyridine (L8) and 2,6-di[(3-pyrazolyl)-3,5-diphenyls] pyridine (L9) were successfully obtained by Condensation reaction with hydrazine hydrate and phenylhydrazine respectively, the above three novel ligands were confirmed by IR, 1HNMR, GC-MS and EA. The Tb3+、Eu3+、Gd3+and Sm3+ complexes of ligand L7 were prepared.
The possible structures of the above complexes were deduced by EA and IR roughly. The fluorescence properties of the solid complexes http://www.999magnet.com/ were investigated in detail,and the ligand L7 was proved to be a better sensitizer for Tb3+ and Eu3+. The Tb3+ complexes with ligand L8 and ligand L9 were also preparedand charactered ,and ligand L8 was found to be a better sensitizer for Tb3+ ions.Furthermore, in order to find and develop new organic fluorescence sensitizers, another list of novel pyridine-2,6-dimethylhydrazine and its derivatives pyridine-2,6-dimethylhydrazones organic ligands: furfurol-pyridine-2,6-dimethylhydrazine (L4)、benzaldehyde-pyridine-2,6-dimethylhydrazine (L5) and salicylaldehyde - pyridine -2,6- dimethyl hydrazine (L6) were synthesized successfully magnet lifter according to the design of molecule and the characteristic of organic fluorescence sensitizers, the above four novel ligands were confirmed by IR, 1HNMR, GC-MS and EA. The Tb3+、and Eu3+ complexes of the four ligands were prepared.The contradistinctive experimental results show that the above four ligands can sensitize Eu3+ and Tb3+ ions to some extent; The ligand which has larger conjugate system is a better fluorescence sensitizer than the smaller conjugate system ligands, the fluorescence of the complexes with electron-donating groups is more intense than that of the complexes with electron-withdrawing groups; When the pH value is about at 7,fluorescence intensities of the complexes are strongest; while the less the dipole moment of solvent molecule is, the stronger the fluorescence intensity is; 更多还原
Pyridine-2,6-dicarboxylic is the best sensitizer of the lanthanide (Tb3+, Eu3+ ions) than salicylic , phenanthroline. And the lanthanide complexes with-β-diketone-kind ligands are of high ability of UV-vis exicitation fluorescence, and the ligands make rare earth ions emit strong characteristic fluorescence by organic ligands’strong UV-vis absorbance and efficienct energy-transfer between the ligands and ions. Therefore,designing and synthesizing novel pyridine-2,6-dicarboxylic derivatives, especially di-β-diketone-kind compounds and their derivatives, is of great importance for searching and developing novel sensitizers for rare earth ions with pyridine-2,6-dicarboxylic as a starting material,and designing the structures of ligands is also a key point to discover new rare-earth ions fluorescent sensitizersIn this paper , a list of di-β-diketone organic ligands and their di-pyrazole derivatives which magnet lifter were not reported by references so far, and have big n-conjugated system were designed,and a novel di-β-diketone organic intermediate 2,6-bisbenzoylactyl pyridine (L7) was synthesized by esterification and Claisen Condensation reaction using pyridine -2,6-dicarboxylic dacid which is a better fluorescent sensitizer as starting material and its two derivatives 2,6-di[(3-pyrazolyl)-5-phenyl] pyridine (L8) and 2,6-di[(3-pyrazolyl)-3,5-diphenyls] pyridine (L9) were successfully obtained by Condensation reaction with hydrazine hydrate and phenylhydrazine respectively, the above three novel ligands were confirmed by IR, 1HNMR, GC-MS and EA. The Tb3+、Eu3+、Gd3+and Sm3+ complexes of ligand L7 were prepared.
The possible structures of the above complexes were deduced by EA and IR roughly. The fluorescence properties of the solid complexes http://www.999magnet.com/ were investigated in detail,and the ligand L7 was proved to be a better sensitizer for Tb3+ and Eu3+. The Tb3+ complexes with ligand L8 and ligand L9 were also preparedand charactered ,and ligand L8 was found to be a better sensitizer for Tb3+ ions.Furthermore, in order to find and develop new organic fluorescence sensitizers, another list of novel pyridine-2,6-dimethylhydrazine and its derivatives pyridine-2,6-dimethylhydrazones organic ligands: furfurol-pyridine-2,6-dimethylhydrazine (L4)、benzaldehyde-pyridine-2,6-dimethylhydrazine (L5) and salicylaldehyde - pyridine -2,6- dimethyl hydrazine (L6) were synthesized successfully magnet lifter according to the design of molecule and the characteristic of organic fluorescence sensitizers, the above four novel ligands were confirmed by IR, 1HNMR, GC-MS and EA. The Tb3+、and Eu3+ complexes of the four ligands were prepared.The contradistinctive experimental results show that the above four ligands can sensitize Eu3+ and Tb3+ ions to some extent; The ligand which has larger conjugate system is a better fluorescence sensitizer than the smaller conjugate system ligands, the fluorescence of the complexes with electron-donating groups is more intense than that of the complexes with electron-withdrawing groups; When the pH value is about at 7,fluorescence intensities of the complexes are strongest; while the less the dipole moment of solvent molecule is, the stronger the fluorescence intensity is; 更多还原
2012年5月14日星期一
Preparation and Characterization of Bridgibg Complexs of Cobalt Cluster and Rare Earth
Preparation and Characterization of Bridgibg Complexs of Cobalt Cluster and Rare Earth
The preparation route of the cluster (CO)6Co2HCCCOOH was improved, and its yield and purity was increased. Cluster (CO)10Co4HCCCOOH was http://www.999magnet.com/ designed as the starting material for this research, however, this oxygen- sensitive cluster is difficult to be obtained in high yield and the preparation route needs to be improved. Some efforts have been made, but the work needs to be continued further. A novel europium ternary complex Eu(Phen)(HCCCOO-)2(ClO4-).C2H5OH (phen is phenanthrolme) was synthesized and characterized by IR, element analysis, Magnetic lifter 1HNMR and fluorescent spectroscopy. This complex can not be used to prepare the designed target complex due to its poor solubility, but it is worthwhile to studying the fluorescent property because of its relative high fluorescent intensity. A bridging complex 更多还原
The preparation route of the cluster (CO)6Co2HCCCOOH was improved, and its yield and purity was increased. Cluster (CO)10Co4HCCCOOH was http://www.999magnet.com/ designed as the starting material for this research, however, this oxygen- sensitive cluster is difficult to be obtained in high yield and the preparation route needs to be improved. Some efforts have been made, but the work needs to be continued further. A novel europium ternary complex Eu(Phen)(HCCCOO-)2(ClO4-).C2H5OH (phen is phenanthrolme) was synthesized and characterized by IR, element analysis, Magnetic lifter 1HNMR and fluorescent spectroscopy. This complex can not be used to prepare the designed target complex due to its poor solubility, but it is worthwhile to studying the fluorescent property because of its relative high fluorescent intensity. A bridging complex 更多还原
Effect of Rare Earth on AZ Series Magnesium Alloys
Effect of Rare Earth on AZ Series Magnesium Alloys
The study of Magnesium alloys have taken more and more attention, especially the strengthen and elongate of Mg alloys.The experiment material of this paper is AZ61 and AZ91 magnesium with addition of rare earth(RE) Ce, Nd and Y separately. A part of the alloys were extruded with the extrusion ratio of 18 and then made specimens together with the as-cast alloys. Through investigation of the microstructures and tests of the mechanical properties, the strengthen mechanism of Segment neodymium magnets RE and hot-extrude process was discussed, which is helpful for further study.The results showed that: compared with magnesium alloys, the RE-Mg alloys have better high-temperature mechanical properties, while that of the ambient-temperature almost the same.
The addition of RE also refined the grain of the Mg alloys. In addition, the optimal content differs with different RE. For as-cast AZ61 and AZ91 alloys, the optimal content of Ce is 1.5%, at where they can reach the maximal ultimate tensile strength σb, yield strength σ0.2 and elongation to failure 5;while the best content for Nd is 0.5%, at where the high-temperature http://www.999magnet.com/ mechanical properties are the best. For extruded alloys, with the content of 0.5% Ce and Nd separately, they have the maximal high-temperature strength and elongation;while the optimal content of Y is 1.5%. After hot-extrusion, the mechanical properties of RE-Mg alloys promote greatly. At ambient-temperature, the σb of extruded AZ61+1.0%Nd alloy can reach 292.6MPa, 61.9% higher than the as-cast alloys of the same component;atl50°C, the σb of extruded AZ61+1.0%Ce alloy can reach 289.1 MPa, 76.4% higher than the as-cast alloys of the same component. Compared with as-cast alloys, the strength hot-extruded alloys Segment neodymium magnets are lOOMPa higher approximately, and the tendencies of that are more ordered: with the rising of the temperature, the elongation rises and the strength fall.It is considered that the addition of RE can refine the grain and purify the grain boundary;the extrusion of alloys can uniform the microstructure and refine the grain, all these can improve the mechanical properties of magnesium alloys.
The study of Magnesium alloys have taken more and more attention, especially the strengthen and elongate of Mg alloys.The experiment material of this paper is AZ61 and AZ91 magnesium with addition of rare earth(RE) Ce, Nd and Y separately. A part of the alloys were extruded with the extrusion ratio of 18 and then made specimens together with the as-cast alloys. Through investigation of the microstructures and tests of the mechanical properties, the strengthen mechanism of Segment neodymium magnets RE and hot-extrude process was discussed, which is helpful for further study.The results showed that: compared with magnesium alloys, the RE-Mg alloys have better high-temperature mechanical properties, while that of the ambient-temperature almost the same.
The addition of RE also refined the grain of the Mg alloys. In addition, the optimal content differs with different RE. For as-cast AZ61 and AZ91 alloys, the optimal content of Ce is 1.5%, at where they can reach the maximal ultimate tensile strength σb, yield strength σ0.2 and elongation to failure 5;while the best content for Nd is 0.5%, at where the high-temperature http://www.999magnet.com/ mechanical properties are the best. For extruded alloys, with the content of 0.5% Ce and Nd separately, they have the maximal high-temperature strength and elongation;while the optimal content of Y is 1.5%. After hot-extrusion, the mechanical properties of RE-Mg alloys promote greatly. At ambient-temperature, the σb of extruded AZ61+1.0%Nd alloy can reach 292.6MPa, 61.9% higher than the as-cast alloys of the same component;atl50°C, the σb of extruded AZ61+1.0%Ce alloy can reach 289.1 MPa, 76.4% higher than the as-cast alloys of the same component. Compared with as-cast alloys, the strength hot-extruded alloys Segment neodymium magnets are lOOMPa higher approximately, and the tendencies of that are more ordered: with the rising of the temperature, the elongation rises and the strength fall.It is considered that the addition of RE can refine the grain and purify the grain boundary;the extrusion of alloys can uniform the microstructure and refine the grain, all these can improve the mechanical properties of magnesium alloys.
Study on New Sintering Method, Structure and Properties of Rare-Earth Magnetostrictive Materials
Study on New Sintering Method, Structure and Properties of Rare-Earth Magnetostrictive Materials
In this paper, a new sintering method is exploited to fabricate Terfenol-D sintered compacts. Besides, the rare-earth giant magnetostrictive materials have been fabricated in an arc-melting furnace, and the structure, magnetic properties and magnetostriction have been investigated.A new sintering method, which is called low-temperature instantaneous liquid-phase sintering with addition of Sn, was exploited to fabricate Terfenol-D sintered compacts. In this work, the influences of powder size, Sn content, compaction pressure, and sintering technique on the magnetic (including magnetostrictive) and mechanical properties have been investigated. It is found that the sintered compacts fabricated by this means possess higher oxidation resistance and the hard brittleness improves. The magnet lifter compacts fabricated with the finest Terfenol-D powder mixed with Sn powder obtain the highest magnetostrictive property. The optimum Sn content is in the range between 8:100 and 10:100. But it is hard to determine the optimum compaction pressure, because the magnetostrictive property deteriorates while the mechanical property improves with the increase of the compaction pressure.
The RTP is more suitable for sintering this material than the common resistance furnace. The large magnetostriction of 546 ppm at 12 kOe is obtained for the sintered compact fabricated at the following conditions: powder size <75μm, a Sn content of 8:100, a compaction pressure of 1.0 GPa, and sintering at 250℃ for 150 seconds in RTP.Study on (Pr0.15Tb0.3Dy0.55(FeM)1.85 (M=Ge, Cu, Co) alloys shows the effect of M substitution for Fe. The substitution of Ge for Fe makes lattice parameter and magnetostrictiondecrease, and the Ge content should no magnet lifter more than 0.2. With the increase of Cu content, the magnetostriction and saturation magnetization decrease, and the Cu content should be limited in 0.25 otherwise RFe3 phase will appear. With the increase of Cu content, the lattice parameter decreases when 0^x^0.1, and increase then http://www.999magnet.com/ decrease when 0.1 ^x^0.25. The introduction of Co induces saturation magnetization decrease, and all samples are entirely MgCu2-type cubic Laves phase when x^0.4. With the increase of Co content, the lattice parameter decreases first when 0^x^0.2, and increase then decrease when 0.2^x^0.4. And low decrease of lattice parameter deteriorates the magnetostriction, while high decrease increases the magnetostriction.
In this paper, a new sintering method is exploited to fabricate Terfenol-D sintered compacts. Besides, the rare-earth giant magnetostrictive materials have been fabricated in an arc-melting furnace, and the structure, magnetic properties and magnetostriction have been investigated.A new sintering method, which is called low-temperature instantaneous liquid-phase sintering with addition of Sn, was exploited to fabricate Terfenol-D sintered compacts. In this work, the influences of powder size, Sn content, compaction pressure, and sintering technique on the magnetic (including magnetostrictive) and mechanical properties have been investigated. It is found that the sintered compacts fabricated by this means possess higher oxidation resistance and the hard brittleness improves. The magnet lifter compacts fabricated with the finest Terfenol-D powder mixed with Sn powder obtain the highest magnetostrictive property. The optimum Sn content is in the range between 8:100 and 10:100. But it is hard to determine the optimum compaction pressure, because the magnetostrictive property deteriorates while the mechanical property improves with the increase of the compaction pressure.
The RTP is more suitable for sintering this material than the common resistance furnace. The large magnetostriction of 546 ppm at 12 kOe is obtained for the sintered compact fabricated at the following conditions: powder size <75μm, a Sn content of 8:100, a compaction pressure of 1.0 GPa, and sintering at 250℃ for 150 seconds in RTP.Study on (Pr0.15Tb0.3Dy0.55(FeM)1.85 (M=Ge, Cu, Co) alloys shows the effect of M substitution for Fe. The substitution of Ge for Fe makes lattice parameter and magnetostrictiondecrease, and the Ge content should no magnet lifter more than 0.2. With the increase of Cu content, the magnetostriction and saturation magnetization decrease, and the Cu content should be limited in 0.25 otherwise RFe3 phase will appear. With the increase of Cu content, the lattice parameter decreases when 0^x^0.1, and increase then http://www.999magnet.com/ decrease when 0.1 ^x^0.25. The introduction of Co induces saturation magnetization decrease, and all samples are entirely MgCu2-type cubic Laves phase when x^0.4. With the increase of Co content, the lattice parameter decreases first when 0^x^0.2, and increase then decrease when 0.2^x^0.4. And low decrease of lattice parameter deteriorates the magnetostriction, while high decrease increases the magnetostriction.
Synthesis and Characterization of Tropolone Azo Metal-complexes
Synthesis and Characterization of Tropolone Azo Metal-complexes
The metallized complexed azo dyes are important metallized complexed dyes used for protein(wool and silk) and polyamide fibers.Conventional metallized azo dyes,containing heavy metal ions such as chromium(Ⅲ), cobalt(Ⅱ) produce a large amount of industrial wastewater,which seriously polluting the ecological environment.Since 1980s,the contents of heavy metal ion Cr3+、Co2+ have strictly been limited in textile.At the same time,the price of copper salt and zinc salt is far lower than chromium salt and cobalt salt.So,it is very important to find environmentally friendly copper(Ⅱ), zinc(Ⅱ) and rare europium(Ⅲ) ion complex dyes as viable alternatives.
The azo compound has the illumination strong magnets performance,synthesizes the rare earth azo dyes,not only advantageous because of its special electronic structure to the dyeing carries on smoothly,the improvement coincidence speed,enhance the level dyeing effect,in rare earth ion and dye member aromatic nucleus structure and other conjugate system union,will cause its excitation energy to reduce.At the same time,is advantageous in causes the dye member the biggest absorption wave to the long wave shift,because this possibly is dyes using the rare earth has one of deep color effect attributes. Moreover the rare-earth element has the specific incisive absorption band in infrared and the ultraviolet visible light area,therefore,its dyeing product luster is bright,is pure.In the http://www.chinamagnets.biz/ paper,tropolone was selected as coupling component to react with respectively with the diazotization components,4-Aminophenol, o-Nitroaniline and 2-amino-4-nitropheno-6-sulfoacid to have synthesized to three mordant dyes,for preparation of metallized complexed azo dyes.Also, the structures of and the character of the metallized mordant dyes were determined by IR,UV,1HNMR.
The above-mentioned three dyes were employed,strong magnets as intermediates to complex respectively with copper(Ⅱ),zinc(Ⅱ) and rare europium(Ⅲ) salts,to prepare nine metallized complexed acidic azo dyes,among which the structures of metallized complexed azo dyes were determined by IR,UV, lHNMR.In synthesizing the complex dyes,the pH value of reaction system was both 7.0～8.0.Meanwhile the reaction temperature of metallized complexed dyes was both 75～80℃By the visible spectra analysis,the structure of the complexed dyes were determined and the metallized complexed dyes characterized,which showing that the maximum absorption wavelength of metallized complexes is between 300nm～550nm,which showed the color of fresh strong magnets yellow.Furthermore,due to coordinate the metal ion,some metallized complexed dyes appeared shoulder peak.
The metallized complexed azo dyes are important metallized complexed dyes used for protein(wool and silk) and polyamide fibers.Conventional metallized azo dyes,containing heavy metal ions such as chromium(Ⅲ), cobalt(Ⅱ) produce a large amount of industrial wastewater,which seriously polluting the ecological environment.Since 1980s,the contents of heavy metal ion Cr3+、Co2+ have strictly been limited in textile.At the same time,the price of copper salt and zinc salt is far lower than chromium salt and cobalt salt.So,it is very important to find environmentally friendly copper(Ⅱ), zinc(Ⅱ) and rare europium(Ⅲ) ion complex dyes as viable alternatives.
The azo compound has the illumination strong magnets performance,synthesizes the rare earth azo dyes,not only advantageous because of its special electronic structure to the dyeing carries on smoothly,the improvement coincidence speed,enhance the level dyeing effect,in rare earth ion and dye member aromatic nucleus structure and other conjugate system union,will cause its excitation energy to reduce.At the same time,is advantageous in causes the dye member the biggest absorption wave to the long wave shift,because this possibly is dyes using the rare earth has one of deep color effect attributes. Moreover the rare-earth element has the specific incisive absorption band in infrared and the ultraviolet visible light area,therefore,its dyeing product luster is bright,is pure.In the http://www.chinamagnets.biz/ paper,tropolone was selected as coupling component to react with respectively with the diazotization components,4-Aminophenol, o-Nitroaniline and 2-amino-4-nitropheno-6-sulfoacid to have synthesized to three mordant dyes,for preparation of metallized complexed azo dyes.Also, the structures of and the character of the metallized mordant dyes were determined by IR,UV,1HNMR.
The above-mentioned three dyes were employed,strong magnets as intermediates to complex respectively with copper(Ⅱ),zinc(Ⅱ) and rare europium(Ⅲ) salts,to prepare nine metallized complexed acidic azo dyes,among which the structures of metallized complexed azo dyes were determined by IR,UV, lHNMR.In synthesizing the complex dyes,the pH value of reaction system was both 7.0～8.0.Meanwhile the reaction temperature of metallized complexed dyes was both 75～80℃By the visible spectra analysis,the structure of the complexed dyes were determined and the metallized complexed dyes characterized,which showing that the maximum absorption wavelength of metallized complexes is between 300nm～550nm,which showed the color of fresh strong magnets yellow.Furthermore,due to coordinate the metal ion,some metallized complexed dyes appeared shoulder peak.
Effect of Yb3+ Concentration on Upconversion Luminescence of Rare-Earth Doped Nano-Oxide
Effect of Yb3+ Concentration on Upconversion Luminescence of Rare-Earth Doped Nano-Oxide
Upconversion (UC) luminescence of nano-oxide doped with rare-earth (RE) ions has attracted much attention due to a wide range of applications, such as fluorescent labels for biomolecules, optical data storage, upconversion lasers, color display, etc. The properties of nanocrystals are strongly influenced by the efficiency of upconversion. Codoped with sensitizer in materials can increase the upconversion efficiency. Yb3+ ion is just a good sensitizer. Moreover, the two energy level structure of Yb3+ ion is splendid, and Yb3+ ions can mighty increase the efficiency of upconversion through sensitizing Er3+ and Tm3+ ions. Thus, in the thesis, the samples of RE ions doped in nano-oxide strong magnets are synthesized by a complex precursor method and excitated by 980nm diode lasers. Furthermore, the effect of Yb3+ concentration on upconversion luminescence is studied.In the system of Y2O3: Tm3+, Yb3+, the intensity of blue (1G4→3H6), red (1G4→3H4), and infrared (3F4→3H6) fluorescence increases at first and then decreases with the increasing of Yb3+ concentration. The effect of Yb3+ concentration on the UC luminescence in Y2O3: Tm3+, Yb3+ nanocrystals is investigated on the basis of spectra and power dependence. When the concentration of Yb3+ ions is high, the cooperative sensitization and the back energy transfer from Tm3+ to Yb3+ are presented and discussed.
The phenomenon observed in the experiment is well explained.It is first discussed that the intensity ratio of blue band (476/488nm) of Tm3+ ion changed with the concentration of Yb3+ and also changed with pump power. It is believed that the change of temperature of laser fleck induced the change of the intensity ratio. The upper separated level of 1G4 state is thermal populated owing to Boltzmann’s distribution. So the intensity ratio of 476/488nm increases with the temperature strong magnets increasing of the laser fleck.Furthermore, the UV spectra of 298nm, 364nm and 391nm are observed in Y2O3:0.2 mol%Tm3+, 3mol%Yb3+ sample. The power dependence indicates that they are six- and five-photon processes respectively.In the system of ZrO2: Er3+, Yb3+, with the increasing of Yb3+ concentration, the intensity of green fluorescence relative to red fluorescence decreases. When the concentration of Yb3+ is 10mol%, a single red UC spectrum is observed. Based on the http://www.chinamagnets.biz/ analyses of spectra and power dependence, it is suggested that the process of energy transfer changed at high Yb3+ concentration, and the back energy transfer (EBT) process is dominating. The particles number populated on the green and red emissions changes with Yb3+ concentration, which causes that the green and red UC fluorescence is tuned by Yb3+ concentration.
Upconversion (UC) luminescence of nano-oxide doped with rare-earth (RE) ions has attracted much attention due to a wide range of applications, such as fluorescent labels for biomolecules, optical data storage, upconversion lasers, color display, etc. The properties of nanocrystals are strongly influenced by the efficiency of upconversion. Codoped with sensitizer in materials can increase the upconversion efficiency. Yb3+ ion is just a good sensitizer. Moreover, the two energy level structure of Yb3+ ion is splendid, and Yb3+ ions can mighty increase the efficiency of upconversion through sensitizing Er3+ and Tm3+ ions. Thus, in the thesis, the samples of RE ions doped in nano-oxide strong magnets are synthesized by a complex precursor method and excitated by 980nm diode lasers. Furthermore, the effect of Yb3+ concentration on upconversion luminescence is studied.In the system of Y2O3: Tm3+, Yb3+, the intensity of blue (1G4→3H6), red (1G4→3H4), and infrared (3F4→3H6) fluorescence increases at first and then decreases with the increasing of Yb3+ concentration. The effect of Yb3+ concentration on the UC luminescence in Y2O3: Tm3+, Yb3+ nanocrystals is investigated on the basis of spectra and power dependence. When the concentration of Yb3+ ions is high, the cooperative sensitization and the back energy transfer from Tm3+ to Yb3+ are presented and discussed.
The phenomenon observed in the experiment is well explained.It is first discussed that the intensity ratio of blue band (476/488nm) of Tm3+ ion changed with the concentration of Yb3+ and also changed with pump power. It is believed that the change of temperature of laser fleck induced the change of the intensity ratio. The upper separated level of 1G4 state is thermal populated owing to Boltzmann’s distribution. So the intensity ratio of 476/488nm increases with the temperature strong magnets increasing of the laser fleck.Furthermore, the UV spectra of 298nm, 364nm and 391nm are observed in Y2O3:0.2 mol%Tm3+, 3mol%Yb3+ sample. The power dependence indicates that they are six- and five-photon processes respectively.In the system of ZrO2: Er3+, Yb3+, with the increasing of Yb3+ concentration, the intensity of green fluorescence relative to red fluorescence decreases. When the concentration of Yb3+ is 10mol%, a single red UC spectrum is observed. Based on the http://www.chinamagnets.biz/ analyses of spectra and power dependence, it is suggested that the process of energy transfer changed at high Yb3+ concentration, and the back energy transfer (EBT) process is dominating. The particles number populated on the green and red emissions changes with Yb3+ concentration, which causes that the green and red UC fluorescence is tuned by Yb3+ concentration.
Effect of Pretreatment on Corrosion Behavior of Al18B4O33w/6061 Composite Coated by Rare Earth Conversion Coating
Effect of Pretreatment on Corrosion Behavior of Al18B4O33w/6061 Composite Coated by Rare Earth Conversion Coating
The Microstructures and the corrossion properties of the coated composite were studied in detail. The Microstructure of the rare earth conversion coating was investigated by scanning electron microscope (SEM) and transsion electron microscope (TEM). X-ray photoelectron spetrum (XPS) was employed to investigate the elements composition and elements valency of the conversion coating. The corrosion behavior of the composite with conversion coating was evaluated by dynamicpolarization curves and electrochemical impedance spectroscopy (EIS).SEM observation indicated neodymium rare earth magnets that the morphologies of convesion coating on the composite were different when various processes of pretreatement were selected. A particle-like conversion coating was obtained by pretreatment with HF or NaOH for a short time while a dry-mud-like conversion coating was produced by pretreatment for a long time. When boiling water (BW) http://www.chinamagnets.biz/ pretreatment was used, an opposite phenomenon was observed.TEM observation revealed that both particle-like and dry-mud-like conversion coating had a fine-crystalline microstructure, but the latter was composed of amorphous at a certain degree.XPS analysis indicated that the conversion coatings were composed of cerium oxide neodymium rare earth magnets and hydroxide. The cerium in the conversion coating exists in the form of: Ce3+ and Ce4+.The high corrosion resistance of coated composite was obtained by pretreated with HF (NaOH) for short time or with BW for long time. The corrosion resistance of the coated composite can be improved significantly by suitable pretreatment.Analysis of EIS revealed that the particle-like conversion coating on the composite can protect the composite effectively, compared with that of dry-mud-like conversion coating.
The Microstructures and the corrossion properties of the coated composite were studied in detail. The Microstructure of the rare earth conversion coating was investigated by scanning electron microscope (SEM) and transsion electron microscope (TEM). X-ray photoelectron spetrum (XPS) was employed to investigate the elements composition and elements valency of the conversion coating. The corrosion behavior of the composite with conversion coating was evaluated by dynamicpolarization curves and electrochemical impedance spectroscopy (EIS).SEM observation indicated neodymium rare earth magnets that the morphologies of convesion coating on the composite were different when various processes of pretreatement were selected. A particle-like conversion coating was obtained by pretreatment with HF or NaOH for a short time while a dry-mud-like conversion coating was produced by pretreatment for a long time. When boiling water (BW) http://www.chinamagnets.biz/ pretreatment was used, an opposite phenomenon was observed.TEM observation revealed that both particle-like and dry-mud-like conversion coating had a fine-crystalline microstructure, but the latter was composed of amorphous at a certain degree.XPS analysis indicated that the conversion coatings were composed of cerium oxide neodymium rare earth magnets and hydroxide. The cerium in the conversion coating exists in the form of: Ce3+ and Ce4+.The high corrosion resistance of coated composite was obtained by pretreated with HF (NaOH) for short time or with BW for long time. The corrosion resistance of the coated composite can be improved significantly by suitable pretreatment.Analysis of EIS revealed that the particle-like conversion coating on the composite can protect the composite effectively, compared with that of dry-mud-like conversion coating.
Investigation on the Properties of Re-Doped CdTe Thin Film Prepared by Vacuum Evaporation
Investigation on the Properties of Re-Doped CdTe Thin Film Prepared by Vacuum Evaporation
Nd-doped and Dy-doped CdTe thin films were prepared by vacuum evaporation on glass substrates, and were annealed at 300℃、400℃、500℃in nitrogen. The characteristics of the samples were tested by X-ray diffraction instrument、X-ray photoelectron Spectrograph and ultraviolet-visible spectrophotometer. According to the result of the test, we analysed and optimized the preparation process of the CdTe thin film. At the same time, the influences of the Nd-doping and Dy-doping on the CdTe thin film was studied.The experimental results showed that the better CdTe thin films were prepared when the mixture ratio of high pure Cd and Te was Cd:Te=1:0.6. When the samples were annealed at T=500℃and t=10min, we can obtain pure polycrystalline CdTe thin films. When the rare earth magnets annealing temperature was lower, there was Te phase in the CdTe thin films. Along with the rise of the annealing temperature, the Te phase content in the films was reduced, and the crystal structure of the samples was turned into pure CdTe phase gradually.The influence of rare-earth doping on the crystallography and optical characteristics of the CdTe thin films was evident. The combination of CdTe was restrained by rare-earth doping, and preferred orientation of crystal plane (111) was observed. With rare-earth doping , the content of Te phase was increased in the CdTe thin films at lower annealing temperature. Nd-doping led to the lattice constant and the crystal cell volume increased, optical transmission increased, rare earth magnets and the optical band gap decreased slightly. Dy-doping led to the grain size increased and the optical band gap decreased evidently.
Nd-doped and Dy-doped CdTe thin films were prepared by vacuum evaporation on glass substrates, and were annealed at 300℃、400℃、500℃in nitrogen. The characteristics of the samples were tested by X-ray diffraction instrument、X-ray photoelectron Spectrograph and ultraviolet-visible spectrophotometer. According to the result of the test, we analysed and optimized the preparation process of the CdTe thin film. At the same time, the influences of the Nd-doping and Dy-doping on the CdTe thin film was studied.The experimental results showed that the better CdTe thin films were prepared when the mixture ratio of high pure Cd and Te was Cd:Te=1:0.6. When the samples were annealed at T=500℃and t=10min, we can obtain pure polycrystalline CdTe thin films. When the rare earth magnets annealing temperature was lower, there was Te phase in the CdTe thin films. Along with the rise of the annealing temperature, the Te phase content in the films was reduced, and the crystal structure of the samples was turned into pure CdTe phase gradually.The influence of rare-earth doping on the crystallography and optical characteristics of the CdTe thin films was evident. The combination of CdTe was restrained by rare-earth doping, and preferred orientation of crystal plane (111) was observed. With rare-earth doping , the content of Te phase was increased in the CdTe thin films at lower annealing temperature. Nd-doping led to the lattice constant and the crystal cell volume increased, optical transmission increased, rare earth magnets and the optical band gap decreased slightly. Dy-doping led to the grain size increased and the optical band gap decreased evidently.
毕节地区晚二叠世煤层地球化学与成煤环境研究
毕节地区晚二叠世煤层地球化学与成煤环境研究
The Coal in west Guizhou province have been succeed a lot of, and it has been a hot researching sphere in geochemistry. But Bijie coal is few researched-Bijie is the second coal resource in Guizhou province. For example, the distribution of REE, and some REE indicate the sediment condition, the source of REE, and etc.Author pickes up 13 pieces of coal sample in the Bijie 11 coal stratum which thickness is more than 0.8m. Compare with the trace element and oxid and ordinary element, REE is few influence by the after active. So REE is good at to reflect the sediment coal condition, and the REE is the central researched in this paper.The distribution of REE in Bijie in later Permnian is comparative enrichment LREE and comparative poor HREE. The left is higher and the right is lower in the picture of REEs distribution.It can be seen that the source of REE is not come Ring neodymium magnet from the sea, because REE in seawater or coral in modern sea is lower than REE in Bijie. As well as, the source of coal is not come from land plants, because the land plants contribute 1% in REE enrichment. So the source is inherited from land materialThe author has further researched the REEs source. Obviously, if we find the explicit land material, we can have the strongest evidence to testify the source of REE. The paper believes that Emeishan basalt is the clearly land material for source of REE. Emeishan basalt has influenced and controlled the distribution of REE in Bijie in later PermnianAnother finding is that REE has indication effect. LREE indicate stratum in Bijie. But the author do not know if the indication Ring neodymium magnet has more universality, which is need to more research. And the sediment condition can be found by the abnormal ofδCe andδEu, which is complementarity the theory of transgression forming coal.
The Coal in west Guizhou province have been succeed a lot of, and it has been a hot researching sphere in geochemistry. But Bijie coal is few researched-Bijie is the second coal resource in Guizhou province. For example, the distribution of REE, and some REE indicate the sediment condition, the source of REE, and etc.Author pickes up 13 pieces of coal sample in the Bijie 11 coal stratum which thickness is more than 0.8m. Compare with the trace element and oxid and ordinary element, REE is few influence by the after active. So REE is good at to reflect the sediment coal condition, and the REE is the central researched in this paper.The distribution of REE in Bijie in later Permnian is comparative enrichment LREE and comparative poor HREE. The left is higher and the right is lower in the picture of REEs distribution.It can be seen that the source of REE is not come Ring neodymium magnet from the sea, because REE in seawater or coral in modern sea is lower than REE in Bijie. As well as, the source of coal is not come from land plants, because the land plants contribute 1% in REE enrichment. So the source is inherited from land materialThe author has further researched the REEs source. Obviously, if we find the explicit land material, we can have the strongest evidence to testify the source of REE. The paper believes that Emeishan basalt is the clearly land material for source of REE. Emeishan basalt has influenced and controlled the distribution of REE in Bijie in later PermnianAnother finding is that REE has indication effect. LREE indicate stratum in Bijie. But the author do not know if the indication Ring neodymium magnet has more universality, which is need to more research. And the sediment condition can be found by the abnormal ofδCe andδEu, which is complementarity the theory of transgression forming coal.
2012年5月11日星期五
Study on Re Carburizing of Steel 20CrMnTi and First Principles Calculation of Effect of Re on the Diffusion of Carbon
Study on Re Carburizing of Steel 20CrMnTi and First Principles Calculation of Effect of Re on the Diffusion of Carbon
This paper deals with the kinetics of layer growth and the effect of rare earth (RE) on the structure and properties of carburized layer during carburizing of steel 20CrMnTi with rare earth added in craburizing gas. Microstructure evolution, microhardness profiles, the kinetics laws of layer growth and the main positions of rare earth existing for RE carburizing had been revealed in this paper as well.Microstructure observation and microhardness profiles measurement results show that the addition of RE could refine microstructure in surface layer, accelerate the carburizing process, decrease the carburizing temperature and increase the hardness of carburized layer. Obviously, it can be Block Neodymium magnets seen that a large amount of dispersed granular carbides precipitate in surface layer of steel 20CrMnTi RE carburized at 880 and 900?C for 5h under carbon potential 1.3%. The microstructure of surface layer after directly quenching consists mainly of acicular martensite, fine granular carbides and a little residual austenite. EDS analysis demonostrates that rare earths exist mainly in carburized layer and carbides.Based on pseudopotential plane wave method of the first principles, the crystal cells of austenite and carbide had been constructed and optimized, as the crystal cell energy, the lattice parameters, the electronic structure, the diffusion activation energy of carbon atom had been calculated as well.
The calculated results of energy http://www.999magnet.com/ and lattice parameters of austenite and carbide indicated that the addition of RE enhances the energy and the volume, and reduce the stability of crystal cells, which is beneficial for carbon to diffuse into the matrix and accelerate the carburizing process. Electronic structure of austenite and carbide showed that adding RE could make the total density of states of crystal cell and carbon atoms aggregate around feimi energy which reduce the stability of crystal cell and carbon atoms, the stability of partial iron atoms also decrease, and all those is Block Neodymium magnets in favor of carbon diffusion. Total charge density of austenite crystal cell increases, the ionic bond effect between carbon and lanthanum atoms is also very strong, which enhances the surface hardness of carburized layer. Carbon atoms tend to diffuse on crystal plane which the bonds are weaker and adding RE could reduce the diffusion activation energy, which could prove resulting from the calculated results of carbon diffusion activation energy in austenite with concentration gradient and in carbide. The presence of rare earths in austenite crystal cell could decrease the carbon diffusion activation energy. The carbon diffusion activation energy increases with decreasing the concentrations of carbon and RE in austenite crystal cell as well as the effect of RE on the carbon diffusion activation energy decreases gradually. 更多还原
This paper deals with the kinetics of layer growth and the effect of rare earth (RE) on the structure and properties of carburized layer during carburizing of steel 20CrMnTi with rare earth added in craburizing gas. Microstructure evolution, microhardness profiles, the kinetics laws of layer growth and the main positions of rare earth existing for RE carburizing had been revealed in this paper as well.Microstructure observation and microhardness profiles measurement results show that the addition of RE could refine microstructure in surface layer, accelerate the carburizing process, decrease the carburizing temperature and increase the hardness of carburized layer. Obviously, it can be Block Neodymium magnets seen that a large amount of dispersed granular carbides precipitate in surface layer of steel 20CrMnTi RE carburized at 880 and 900?C for 5h under carbon potential 1.3%. The microstructure of surface layer after directly quenching consists mainly of acicular martensite, fine granular carbides and a little residual austenite. EDS analysis demonostrates that rare earths exist mainly in carburized layer and carbides.Based on pseudopotential plane wave method of the first principles, the crystal cells of austenite and carbide had been constructed and optimized, as the crystal cell energy, the lattice parameters, the electronic structure, the diffusion activation energy of carbon atom had been calculated as well.
The calculated results of energy http://www.999magnet.com/ and lattice parameters of austenite and carbide indicated that the addition of RE enhances the energy and the volume, and reduce the stability of crystal cells, which is beneficial for carbon to diffuse into the matrix and accelerate the carburizing process. Electronic structure of austenite and carbide showed that adding RE could make the total density of states of crystal cell and carbon atoms aggregate around feimi energy which reduce the stability of crystal cell and carbon atoms, the stability of partial iron atoms also decrease, and all those is Block Neodymium magnets in favor of carbon diffusion. Total charge density of austenite crystal cell increases, the ionic bond effect between carbon and lanthanum atoms is also very strong, which enhances the surface hardness of carburized layer. Carbon atoms tend to diffuse on crystal plane which the bonds are weaker and adding RE could reduce the diffusion activation energy, which could prove resulting from the calculated results of carbon diffusion activation energy in austenite with concentration gradient and in carbide. The presence of rare earths in austenite crystal cell could decrease the carbon diffusion activation energy. The carbon diffusion activation energy increases with decreasing the concentrations of carbon and RE in austenite crystal cell as well as the effect of RE on the carbon diffusion activation energy decreases gradually. 更多还原
Research on Catalytic Graphitization of Polyacrylonitrile-Based Carbon Fibers
Research on Catalytic Graphitization of Polyacrylonitrile-Based Carbon Fibers
Carbon fibers are one of the most commonly used reinforcing fibers. They have not only exceptional mechanical properties but also chemical stability, which makes them ideal for high performance composites. Polyacrylonitrile (PAN)-based carbon fibers have been found to be most suitable for making high-performance carbon fibers. In order to obtain high-strain and high-modulus of carbon fiber, elevation of its graphitization degree has become necessary. High-temperature heat treatment is required to provide energy for atomic displacements and to develop graphitization structure in carbon materials. In order to improve the graphitization degree of non-graphitizing carbon materials, adding catalysts are usually used to accelerate the graphitization of non-graphitizing carbon, which is called catalytic graphitization. Here, taking PAN–based carbon fibers as model, we investigated the catalytic graphitization of PAN–based carbon fibers.(1) It is well known that the graphitization of carbon may be limited by some factors, such as the dispersion of the catalyst in carbon and the extent of interfacial contact between the carbon and the catalyst, which are related with the methods of addition of the catalyst to the carbon. In this thesis, we introduced a simple and efficient redox deposition method using KMnO4 as a precursor to coat closely PAN-based carbon fiber with a uniform layer of manganese oxides by a direct redox Special shape NdFeB magnets reaction between the carbons and permanganate ions, which provided an improvement of the catalyst dispersion. The catalytic graphitization of fibers coated with manganese oxidess was investigated by X-ray diffraction (XRD) and Raman spectroscopy. It indicates that the graphitization of PAN-based carbon fibers was accelerated in the present of the manganese oxides coating. High degree of graphitization in this manganese oxides coated fibers is observed clearly at HTT of 1600℃. The effects of the heat treatment temperatures and the deposition parameters of manganese oxides (temperature and time) on the graphitization process of PAN-based carbon fibers were also studied.(2) http://www.999magnet.com/ An extensive study has been made for the catalytic graphitization of carbon by various elements, such as Al, Cr, Mn, Fe, Co, Ni, Ca, Ti, V, Mo,
W and B. However, the catalytic effects of rare-earth elements on the graphitization of nongraphitizing carbon have been seldom studied. In this thesis, we introduced the rare-earth catalysts, yttrium, by electrodeposition and lanthanum nitrate by liquid method, to catalyze the graphitization of non-graphitizing PAN-based carbon fibers. The effects of the yttrium (lanthanum nitrate) content and the HTT on the catalytic graphitization were investigated by X-ray diffraction and Raman spectroscopy. It indicats that rare-earth elements can accelerate the graphitization process, especially at temperatures of 2000~2400℃, which has been proved by the variation of crystallite parameters.(3) Carbon fibers were pretreated by plasma. Then the process of immersing fibers to HBO3 solution was adopted to disperse the B element. The effects of discharge power and plasma-tretment time on catalytic Special shape NdFeB magnets graphitization of PAN-based carbon fibers were studied by scanning electron microscopy (SEM), X-ray diffraction and Raman spectroscopy. The results from scanning electron microscopy show that the surface morphology of carbon fibers has changed after the pretreatment. X-ray diffraction and Raman spectroscopy results show that the catalytic graphitization of pretreated PAN-base carbon fibers can be improved at suitable discharge power treatment, which is beneficial for boron-doping. While discharge power increase further, the opposite effect can be observed because the structure of graphite crystal would be destroyed, which have negative influence on the catalytic graphitization of PAN-based carbon fibers. 更多还原
Carbon fibers are one of the most commonly used reinforcing fibers. They have not only exceptional mechanical properties but also chemical stability, which makes them ideal for high performance composites. Polyacrylonitrile (PAN)-based carbon fibers have been found to be most suitable for making high-performance carbon fibers. In order to obtain high-strain and high-modulus of carbon fiber, elevation of its graphitization degree has become necessary. High-temperature heat treatment is required to provide energy for atomic displacements and to develop graphitization structure in carbon materials. In order to improve the graphitization degree of non-graphitizing carbon materials, adding catalysts are usually used to accelerate the graphitization of non-graphitizing carbon, which is called catalytic graphitization. Here, taking PAN–based carbon fibers as model, we investigated the catalytic graphitization of PAN–based carbon fibers.(1) It is well known that the graphitization of carbon may be limited by some factors, such as the dispersion of the catalyst in carbon and the extent of interfacial contact between the carbon and the catalyst, which are related with the methods of addition of the catalyst to the carbon. In this thesis, we introduced a simple and efficient redox deposition method using KMnO4 as a precursor to coat closely PAN-based carbon fiber with a uniform layer of manganese oxides by a direct redox Special shape NdFeB magnets reaction between the carbons and permanganate ions, which provided an improvement of the catalyst dispersion. The catalytic graphitization of fibers coated with manganese oxidess was investigated by X-ray diffraction (XRD) and Raman spectroscopy. It indicates that the graphitization of PAN-based carbon fibers was accelerated in the present of the manganese oxides coating. High degree of graphitization in this manganese oxides coated fibers is observed clearly at HTT of 1600℃. The effects of the heat treatment temperatures and the deposition parameters of manganese oxides (temperature and time) on the graphitization process of PAN-based carbon fibers were also studied.(2) http://www.999magnet.com/ An extensive study has been made for the catalytic graphitization of carbon by various elements, such as Al, Cr, Mn, Fe, Co, Ni, Ca, Ti, V, Mo,
W and B. However, the catalytic effects of rare-earth elements on the graphitization of nongraphitizing carbon have been seldom studied. In this thesis, we introduced the rare-earth catalysts, yttrium, by electrodeposition and lanthanum nitrate by liquid method, to catalyze the graphitization of non-graphitizing PAN-based carbon fibers. The effects of the yttrium (lanthanum nitrate) content and the HTT on the catalytic graphitization were investigated by X-ray diffraction and Raman spectroscopy. It indicats that rare-earth elements can accelerate the graphitization process, especially at temperatures of 2000~2400℃, which has been proved by the variation of crystallite parameters.(3) Carbon fibers were pretreated by plasma. Then the process of immersing fibers to HBO3 solution was adopted to disperse the B element. The effects of discharge power and plasma-tretment time on catalytic Special shape NdFeB magnets graphitization of PAN-based carbon fibers were studied by scanning electron microscopy (SEM), X-ray diffraction and Raman spectroscopy. The results from scanning electron microscopy show that the surface morphology of carbon fibers has changed after the pretreatment. X-ray diffraction and Raman spectroscopy results show that the catalytic graphitization of pretreated PAN-base carbon fibers can be improved at suitable discharge power treatment, which is beneficial for boron-doping. While discharge power increase further, the opposite effect can be observed because the structure of graphite crystal would be destroyed, which have negative influence on the catalytic graphitization of PAN-based carbon fibers. 更多还原
2012年5月7日星期一
The Photocatalytic Activity Research of Re-Doped TiO2 Films under Visible Light
The Photocatalytic Activity Research of Re-Doped TiO2 Films under Visible Light
The photocatalytic oxidation technique of TiO2 has been paid more and more attention for the advantage of less cost, mild reaction condition, easy operation and less secondary pollution. However TiO2 may show photocatalytic activity only by irradiation of ultraviolet(UV) light for its wide band gap(Eg=3.2eV). But the proportion of UV light to the strong magnets sun light is very small. In addition, easy recombination of photo-induced electrons and holes makes the efficiency of photoquantum lower. These unfavorable factors have the photocatalytic oxidation technique of TiO2 limited in practice. Considering the problems above, the idea that TiO2 photocatalyst is doped with rare-earth ions(La3+,Eu3+,Nd3+) is presented to improve the photocatalytic performance of TiO2 and enhance the absorbing wavelength to the visible light wavelength.In this paper, the TiO2 film was prepared by sol-gel method. The effect of the dosage of different ingredients, pH and sintering process on the preparation of sol and film, structure of TiO2 film and photocatalytic performance were studied. The result showed that the optimal parameter of mixture ratio of Ti(OC4H9)4, CH3CH2OH, H2O and nitric acid was 1:3:0.1:0.05. The best number of coating cycles was 5. The photocatalytic activity of different sintering under visible light was studied too. When the sintering temperature was 500℃, the content of anatase TiO2 was high and TiO2 films had considerable photocatalytic activities. In order to get higher photocatalytic performance under visible light, the rare-earth ions were added into the TiO2 sol, http://www.chinamagnets.biz/ and the photocatalytic activity of TiO2 films was studied too. The result showed that photocatalytic property can be improved by adding suitable dosage of rare-earth ions. Nd-doped TiO2 film had the highest photocatalytic property, La-doped TiO2 was inferior, Eu-doped TiO2 was the lowest of all. When the dopant concentration of Nd was 0.9mol%, the photocatalytic remove ratio is 23.9% higher than the pure film without doped. SEM, AFM, XRD and XPS were used to observe and analyze the structure of undoped TiO2 and doped TiO2 films. The results showed that the rare-earth ions were doped into the TiO2 films, which made the grains smaller, led to aberrance of the crystals and absorbed more -OH. All these changes can increase the 更多还原
The photocatalytic oxidation technique of TiO2 has been paid more and more attention for the advantage of less cost, mild reaction condition, easy operation and less secondary pollution. However TiO2 may show photocatalytic activity only by irradiation of ultraviolet(UV) light for its wide band gap(Eg=3.2eV). But the proportion of UV light to the strong magnets sun light is very small. In addition, easy recombination of photo-induced electrons and holes makes the efficiency of photoquantum lower. These unfavorable factors have the photocatalytic oxidation technique of TiO2 limited in practice. Considering the problems above, the idea that TiO2 photocatalyst is doped with rare-earth ions(La3+,Eu3+,Nd3+) is presented to improve the photocatalytic performance of TiO2 and enhance the absorbing wavelength to the visible light wavelength.In this paper, the TiO2 film was prepared by sol-gel method. The effect of the dosage of different ingredients, pH and sintering process on the preparation of sol and film, structure of TiO2 film and photocatalytic performance were studied. The result showed that the optimal parameter of mixture ratio of Ti(OC4H9)4, CH3CH2OH, H2O and nitric acid was 1:3:0.1:0.05. The best number of coating cycles was 5. The photocatalytic activity of different sintering under visible light was studied too. When the sintering temperature was 500℃, the content of anatase TiO2 was high and TiO2 films had considerable photocatalytic activities. In order to get higher photocatalytic performance under visible light, the rare-earth ions were added into the TiO2 sol, http://www.chinamagnets.biz/ and the photocatalytic activity of TiO2 films was studied too. The result showed that photocatalytic property can be improved by adding suitable dosage of rare-earth ions. Nd-doped TiO2 film had the highest photocatalytic property, La-doped TiO2 was inferior, Eu-doped TiO2 was the lowest of all. When the dopant concentration of Nd was 0.9mol%, the photocatalytic remove ratio is 23.9% higher than the pure film without doped. SEM, AFM, XRD and XPS were used to observe and analyze the structure of undoped TiO2 and doped TiO2 films. The results showed that the rare-earth ions were doped into the TiO2 films, which made the grains smaller, led to aberrance of the crystals and absorbed more -OH. All these changes can increase the 更多还原
Synthesize and Research on Nano-composite Ferrite Absorber
Synthesize and Research on Nano-composite Ferrite Absorber
Nano-NiZn ferrite, nano-Ba ferrite and nano-NiZnCu ferrite were produced by sol-gel method and their properties were measured. The results of experiments indicate that these compound ferrites have some microwave absorption properties and nano-NiZn ferrite is best than the others in the microwave absorption properties. Then different amount of rare earth cerium was dopted in nano-NiZn ferrrite and nano-NiZnCu ferrite, different amount of rare earth lanthanum was dopted in nano-Ba ferrite. We found that the microwave absorption properties of three kinds of ferrite neodymium rare earth magnets change as different amount of rare earth dopted.In Ni0.2Zn0.8Fe2-xCexO4 (x=0, 0.01, 0.03, 0.07) four different materials, when the mol ratio of rare earth cerium is 7 % (x=0.07), the microwave absorption property is best. At the same time, the microwave absorption property of x=0.01 is lower than x=0. In Ni0.25Cu0.25Zn0.5Fe2-xCexO4 (x=0, 0.03, 0.05, 0.07, 0.1) five different materials, when the mol ratio of rare earth cerium is 7% (x=0.07) , the microwave absorption property is best and the value of its biggest absorption peak achieves 29.634dB, the microwave absorption property http://www.chinamagnets.biz/ of x=0.1 is lower than x=0.07. These indicate that the absorption properties of these materials don’t change as the 更多还原
Nano-NiZn ferrite, nano-Ba ferrite and nano-NiZnCu ferrite were produced by sol-gel method and their properties were measured. The results of experiments indicate that these compound ferrites have some microwave absorption properties and nano-NiZn ferrite is best than the others in the microwave absorption properties. Then different amount of rare earth cerium was dopted in nano-NiZn ferrrite and nano-NiZnCu ferrite, different amount of rare earth lanthanum was dopted in nano-Ba ferrite. We found that the microwave absorption properties of three kinds of ferrite neodymium rare earth magnets change as different amount of rare earth dopted.In Ni0.2Zn0.8Fe2-xCexO4 (x=0, 0.01, 0.03, 0.07) four different materials, when the mol ratio of rare earth cerium is 7 % (x=0.07), the microwave absorption property is best. At the same time, the microwave absorption property of x=0.01 is lower than x=0. In Ni0.25Cu0.25Zn0.5Fe2-xCexO4 (x=0, 0.03, 0.05, 0.07, 0.1) five different materials, when the mol ratio of rare earth cerium is 7% (x=0.07) , the microwave absorption property is best and the value of its biggest absorption peak achieves 29.634dB, the microwave absorption property http://www.chinamagnets.biz/ of x=0.1 is lower than x=0.07. These indicate that the absorption properties of these materials don’t change as the 更多还原
Preparation and Characterization of the Nanometer-scale Rare Earth Oxide Particles by Thermal Explosion
Preparation and Characterization of the Nanometer-scale Rare Earth Oxide Particles by Thermal Explosion
With the development of science research, nanometer scale materials have recently attracted a lot of research interests and developed very rapidly. Nanometer scale materials have unique properties, such as force, electricity, light, magnetism and heat effect due to their superficial effect, bulk effect, quantum dimension effect and macroscopic quantum tunneling effect. Especially nanometer scale rare earth oxide such as neodymium oxide samarium oxide have many properties and application which the traditional solid never have. In this paper, we discuss preparation of the nanometer-scale rare earth oxide particles such as Sm2O3, Nd2O3 and Ce0.8Sm0.2O1.9 via an easy thermo-decomposition method of their complexes. The modification of the complexes and oxide particles are presented.(1) Preparation and modification of Sm2O3We Use Sm(NO3)3·6H2O and nitro-rare earth magnets benzoic acid as raw materials, and adjust pH to precipitation appear, and calcining this precipitation at given temperature, we can obtain the high purity Sm2O3. The influences of kinds of nitro-benzoic acid, raw materials ratio, reaction time, pH of solution and drying time on particle size were investigated. In addition, the products were characterized by transmission electron microscope (TEM), and the particle size of the product was 3-20nm and well dispersed. We can know the powder is very pure from the X-ray powder diffraction (XRD) results.(2) Preparation and modification of Nd2O3We Use Nd(NO3)3·6H2O and nitro-benzoic acid as raw materials, adjust pH to precipitation appear. Calcining this precipitation at given temperature, we can obtain the nanometer-sized Nd2O3. The products were characterized by transmission electron microscope (TEM). The particle size was 3-20 nra. The http://www.chinamagnets.biz/ powder synthesized by this method shows a high dispersion behaviors and its average size is increasing with the temperature increasing.(3) Preparation and modification of SmxCeyOzUsing Sm(NO3)3·6H2O, Ce(NO3)2·6H2O and nitro-benzoic acid as raw materials, and adjust pH to precipitation appear. Calcining this precipitation at given temperature and we can obtain the nanometer-sized SmxCeyOz. The particle size was 10-40 nm. The powder synthesized by this method shows a high dispersion behavior. 更多还原
With the development of science research, nanometer scale materials have recently attracted a lot of research interests and developed very rapidly. Nanometer scale materials have unique properties, such as force, electricity, light, magnetism and heat effect due to their superficial effect, bulk effect, quantum dimension effect and macroscopic quantum tunneling effect. Especially nanometer scale rare earth oxide such as neodymium oxide samarium oxide have many properties and application which the traditional solid never have. In this paper, we discuss preparation of the nanometer-scale rare earth oxide particles such as Sm2O3, Nd2O3 and Ce0.8Sm0.2O1.9 via an easy thermo-decomposition method of their complexes. The modification of the complexes and oxide particles are presented.(1) Preparation and modification of Sm2O3We Use Sm(NO3)3·6H2O and nitro-rare earth magnets benzoic acid as raw materials, and adjust pH to precipitation appear, and calcining this precipitation at given temperature, we can obtain the high purity Sm2O3. The influences of kinds of nitro-benzoic acid, raw materials ratio, reaction time, pH of solution and drying time on particle size were investigated. In addition, the products were characterized by transmission electron microscope (TEM), and the particle size of the product was 3-20nm and well dispersed. We can know the powder is very pure from the X-ray powder diffraction (XRD) results.(2) Preparation and modification of Nd2O3We Use Nd(NO3)3·6H2O and nitro-benzoic acid as raw materials, adjust pH to precipitation appear. Calcining this precipitation at given temperature, we can obtain the nanometer-sized Nd2O3. The products were characterized by transmission electron microscope (TEM). The particle size was 3-20 nra. The http://www.chinamagnets.biz/ powder synthesized by this method shows a high dispersion behaviors and its average size is increasing with the temperature increasing.(3) Preparation and modification of SmxCeyOzUsing Sm(NO3)3·6H2O, Ce(NO3)2·6H2O and nitro-benzoic acid as raw materials, and adjust pH to precipitation appear. Calcining this precipitation at given temperature and we can obtain the nanometer-sized SmxCeyOz. The particle size was 10-40 nm. The powder synthesized by this method shows a high dispersion behavior. 更多还原
Numerical Simulation of Electrical Field and Flow Field for Rare Earth Electrolyzer
Numerical Simulation of Electrical Field and Flow Field for Rare Earth Electrolyzer
Rare earth electrolyzer exists the complex field of physics; Electrical field is the source of other physical field. Thermal field and flow field are the important factors to determine whether the rare earth electrolytic cell to carry out. How to design the rational design of the flow field and the thermal field is the key factor to decide whether the electrolyze design is good or bad, so the research of the electrical field, the flow field is very important.This article makes the following specific tasks:1)This article improves the existing 3 KA electrolyzer done to become buried anode non-adherent-cell anode and the whole buried-cell. Through the electrical field result, we find that no matter whether the anode approach to wall, the voltage of all buried wall of the cell is 1.3 V lower than melt under the same conditions by their comparative study.2)This article analyzes that the different anode electrode and the Cylinder neodymium magnet different height how to impact the entire buried non-adherent anode-cell’s electric field. The increase of the anode diameter will increase the cell voltage and current strength will be reduced, the best simulation of the anode diameter is 22 cm; electrode high degree of change greatly impacts the cell voltage, we get the result that the best simulation of the electrode height is 22 cm. We use the height of 22 cm, anode diameter of 22 cm‘s entire buried electrolyzer for the physical model to calculate the flow field, and get the result that the flow of the entire buried non-adherent anode-cell is better than all buried anode-cell.3)use the same method to simulate the 10 KA-cell electrical field, and analyzes the impact on the electrical field in different insertion depth, pitch and a very different anode consumption.We get the result that each insertion depth increases the additional 2 cm, melt voltage reduces the 0.6 V around.4)we use the anodic current density reached through the simulated cathode to get the speed of gas at different heights http://www.chinamagnets.biz/ and gas volume function, the calculation result is used as the initial condition of the flow field, we get the flow simulation results that only the bubble impacts using the FLUENT software. And analyzes the impact on flow field in different pitch depth, found that the double vortex diameter formed in the middle place of anode increases with the increase of the distance between cathode and anode.With the insertion depth increased, the anode formed around the vortex will be increasingly approach to anode.5)Through the analysis of inline 10 KA electrolyzer heat balance, we get that we can reduce the open cell area and the cell surface temperature to reduce the loss of some heat. 更多还原
Rare earth electrolyzer exists the complex field of physics; Electrical field is the source of other physical field. Thermal field and flow field are the important factors to determine whether the rare earth electrolytic cell to carry out. How to design the rational design of the flow field and the thermal field is the key factor to decide whether the electrolyze design is good or bad, so the research of the electrical field, the flow field is very important.This article makes the following specific tasks:1)This article improves the existing 3 KA electrolyzer done to become buried anode non-adherent-cell anode and the whole buried-cell. Through the electrical field result, we find that no matter whether the anode approach to wall, the voltage of all buried wall of the cell is 1.3 V lower than melt under the same conditions by their comparative study.2)This article analyzes that the different anode electrode and the Cylinder neodymium magnet different height how to impact the entire buried non-adherent anode-cell’s electric field. The increase of the anode diameter will increase the cell voltage and current strength will be reduced, the best simulation of the anode diameter is 22 cm; electrode high degree of change greatly impacts the cell voltage, we get the result that the best simulation of the electrode height is 22 cm. We use the height of 22 cm, anode diameter of 22 cm‘s entire buried electrolyzer for the physical model to calculate the flow field, and get the result that the flow of the entire buried non-adherent anode-cell is better than all buried anode-cell.3)use the same method to simulate the 10 KA-cell electrical field, and analyzes the impact on the electrical field in different insertion depth, pitch and a very different anode consumption.We get the result that each insertion depth increases the additional 2 cm, melt voltage reduces the 0.6 V around.4)we use the anodic current density reached through the simulated cathode to get the speed of gas at different heights http://www.chinamagnets.biz/ and gas volume function, the calculation result is used as the initial condition of the flow field, we get the flow simulation results that only the bubble impacts using the FLUENT software. And analyzes the impact on flow field in different pitch depth, found that the double vortex diameter formed in the middle place of anode increases with the increase of the distance between cathode and anode.With the insertion depth increased, the anode formed around the vortex will be increasingly approach to anode.5)Through the analysis of inline 10 KA electrolyzer heat balance, we get that we can reduce the open cell area and the cell surface temperature to reduce the loss of some heat. 更多还原
三明治型稀土金属(四氮杂)卟啉、酞菁配合物的合成及性质研究
三明治型稀土金属(四氮杂)卟啉、酞菁配合物的合成及性质研究
Porphyrins, along with their artificial analogues tetraazaporphyrins and phthalocyanines, belong to a cyclic tetrapyrrole family in which the four pyrrole or isoindole nitrogen atoms are able to coordinate with a range of metal ions. With large metal centers which favor octa-coordination (e.g. rare earths, actinides), sandwich-type complexes in the form of double- or triple-deckers can be formed. Since the first sandwich-type metal phthalocyaninato double-decker complex was synthesized in 1936, people have contributed much attention to such complexes, and a variety of sandwich-type double- and triple-deckers with porphyrinato and/or phthalocyaninato ligands have been synthesized and researched deeply. Due to the intramolecularπ-πinteractions and the intrinsic nature Cube neodymium magnet of the metal centers, these complexes show extraordinary optical, electronic, thermodynamic and magnetic properties, which enable them to be used as materials of novel molecular conductor, molecular magnet, molecular electronics, optical limitation, non-linear optics, gas sensor, electrochromism, opti-electronic transformation and liquid crystal etc..Moreover, photochromic materials are attached much importance to owing to their potential application in the areas of optical memory, information storage, dopes, pigments and other correlative industries. We can use their two forms (open form and closed form) in different colors to record information in binary system. In recent years, it has become a popular field to design and synthesize this kind of materials with novel structures or availing in practice. Among the numerous photochromic compounds, 1,2-diarylethene, especially 1,2-bisthienylethene (BET) derivatives have been regarded as an outstanding type, due to their sufficient thermal stability and very high resistance to photo-fatigue. Researchers have being paid much enthusiasm and energy to synthesize this kind of compounds. On the one hand, they wish to design novel molecular materials with advanced or new features; on the other hand, they expect to meet the needs of practical application.My research work in these fields has been focused on the following respects: 1. Synthesis and spectroscopic characterization of mixed 5,10,15,20-tetrakis(4-chlorophenyl)porphyrinato and l,4,8,ll,15,18,22,25-octakis(1-butyloxy)phthalocyaninato rare earth(III) double-decker complexesReaction of the half-sandwich complexes [REIII(TClPP)(acac)] [RE = Sm, Eu, Tb, Dy, Y, Ho, Lu; TClPP = meso-tetrakis(4-chlorophenyl)porphyrinate; acac = http://www.chinamagnets.biz/ acetylacetonate], generated in situ from RE(acac)3 ? nH2O and H2(TC1PP), with 1,4,8,11,15,18,22,25-octakis(1-butyloxy)phthalocyanine [H2Pc(α-OC4H9)8] in refluxing n-octanol gave exclusively the protonated mixed (phthalocyaninato)(porphyrinato) rare earth double-deckersHREIII(TClPP)[Pc(α-OC4H9)8] [RE = Sm, Eu, Tb, Dy, Y, Ho, Lu]. Considering that both neutral mixed (phthalocyaninato)(porphyrinato) rare earth double-deckers REIII(TClPP)[Pc(α-OC5H11)4] (RE = Sm, Eu, Y) and the protonated analogues HMIII(TClPP)[Pc(α-OC5H11)4] (RE = Sm, Eu, Y) were isolated from the similar reactions just using H2[Pc(α-OC5H11)4] instead of H2Pc(α-OC4H9)8, and only neutral analogues [REIII(TClPP)(Pc)] were isolated in our former work, we noticed thatα-alkoxylation of the phthalocyanine ligand can stabilize the protonated form, which was supported by molecular orbital calculations. These observations clearly showed the importance of the position and number of substituents at the phthalocyanine ligand in controlling the nature of the isolated mixed (phthalocyaninato)(porphyrinato) rare earth double-deckers. The series of protonated complexes HREIII(TClPP)[Pc(α-OC4H9)8] were characterized by elemental analysis and various spectroscopic methods (MS, NMR, UV-Vis, near-IR, and IR).2. Synthesis and spectroscopic characterization of photochromic half-sndwichand sandwich type rare earth complexes containing tetraazaporphyrinato ligandHalf-sandwich type rare earth tatraazaporphyrinato complexes RE[TAP(C7H9S)8](acac) [RE = Nd, Eu, Y, Ho, Lu; TAP(C7H9S)8 = 2,3,7,8,12,13,17,18-octakis-(2’,4’,5’-trimethyl -3 ’-thienyl)tetraazaporphyrinato] have been prepared by treating 1,2-dicyano-1,2-bis(2’,4’,5’-trimethyl-3’-thienyl)ethane in the presence of DBU with the corresponding RE(acac)3 ? nH2O (acac = acetylacetonate) in n-pentanol. And reactions of the half-sandwich type complexes [REIII(Pc)(acac)] with 1,2-dicyano-1,2-bis(2’,4’,5’-trimethyl-3’-thienyl)ethane in the presence of DBU in n-pentanol, have led to the isolation of protonated mixed (tetraazaporphyrinato)(phthalocyaninato) rare earth double-deckersHRE[TAP(C7H9S)8](Pc) (RE = Nd, Eu, Y, Ho, Lu). http://www.chinamagnets.biz/ As far as we know, these double-deckers are the first sandwich type compounds mixing tetraazaporphyrinato and phthalocyaninato ligands, as well as the first sandwich-type bisthienylethene derivatives in the photochromic family. We managed to synthysize half-sandwich and sandwich type rare earth complexes containing tetraazaporphyrinato ligand in the ways that we usually prepare phthalocyaninato complexes. So approaches to synthesize tetraazaporphyrinato compounds have been increased. These complexes were characterized by elemental analysis and various spectroscopic methods (MS, NMR, UV-Vis, and IR). And we researched the photochromic feature of these compounds in detail. 更多还原
Porphyrins, along with their artificial analogues tetraazaporphyrins and phthalocyanines, belong to a cyclic tetrapyrrole family in which the four pyrrole or isoindole nitrogen atoms are able to coordinate with a range of metal ions. With large metal centers which favor octa-coordination (e.g. rare earths, actinides), sandwich-type complexes in the form of double- or triple-deckers can be formed. Since the first sandwich-type metal phthalocyaninato double-decker complex was synthesized in 1936, people have contributed much attention to such complexes, and a variety of sandwich-type double- and triple-deckers with porphyrinato and/or phthalocyaninato ligands have been synthesized and researched deeply. Due to the intramolecularπ-πinteractions and the intrinsic nature Cube neodymium magnet of the metal centers, these complexes show extraordinary optical, electronic, thermodynamic and magnetic properties, which enable them to be used as materials of novel molecular conductor, molecular magnet, molecular electronics, optical limitation, non-linear optics, gas sensor, electrochromism, opti-electronic transformation and liquid crystal etc..Moreover, photochromic materials are attached much importance to owing to their potential application in the areas of optical memory, information storage, dopes, pigments and other correlative industries. We can use their two forms (open form and closed form) in different colors to record information in binary system. In recent years, it has become a popular field to design and synthesize this kind of materials with novel structures or availing in practice. Among the numerous photochromic compounds, 1,2-diarylethene, especially 1,2-bisthienylethene (BET) derivatives have been regarded as an outstanding type, due to their sufficient thermal stability and very high resistance to photo-fatigue. Researchers have being paid much enthusiasm and energy to synthesize this kind of compounds. On the one hand, they wish to design novel molecular materials with advanced or new features; on the other hand, they expect to meet the needs of practical application.My research work in these fields has been focused on the following respects: 1. Synthesis and spectroscopic characterization of mixed 5,10,15,20-tetrakis(4-chlorophenyl)porphyrinato and l,4,8,ll,15,18,22,25-octakis(1-butyloxy)phthalocyaninato rare earth(III) double-decker complexesReaction of the half-sandwich complexes [REIII(TClPP)(acac)] [RE = Sm, Eu, Tb, Dy, Y, Ho, Lu; TClPP = meso-tetrakis(4-chlorophenyl)porphyrinate; acac = http://www.chinamagnets.biz/ acetylacetonate], generated in situ from RE(acac)3 ? nH2O and H2(TC1PP), with 1,4,8,11,15,18,22,25-octakis(1-butyloxy)phthalocyanine [H2Pc(α-OC4H9)8] in refluxing n-octanol gave exclusively the protonated mixed (phthalocyaninato)(porphyrinato) rare earth double-deckersHREIII(TClPP)[Pc(α-OC4H9)8] [RE = Sm, Eu, Tb, Dy, Y, Ho, Lu]. Considering that both neutral mixed (phthalocyaninato)(porphyrinato) rare earth double-deckers REIII(TClPP)[Pc(α-OC5H11)4] (RE = Sm, Eu, Y) and the protonated analogues HMIII(TClPP)[Pc(α-OC5H11)4] (RE = Sm, Eu, Y) were isolated from the similar reactions just using H2[Pc(α-OC5H11)4] instead of H2Pc(α-OC4H9)8, and only neutral analogues [REIII(TClPP)(Pc)] were isolated in our former work, we noticed thatα-alkoxylation of the phthalocyanine ligand can stabilize the protonated form, which was supported by molecular orbital calculations. These observations clearly showed the importance of the position and number of substituents at the phthalocyanine ligand in controlling the nature of the isolated mixed (phthalocyaninato)(porphyrinato) rare earth double-deckers. The series of protonated complexes HREIII(TClPP)[Pc(α-OC4H9)8] were characterized by elemental analysis and various spectroscopic methods (MS, NMR, UV-Vis, near-IR, and IR).2. Synthesis and spectroscopic characterization of photochromic half-sndwichand sandwich type rare earth complexes containing tetraazaporphyrinato ligandHalf-sandwich type rare earth tatraazaporphyrinato complexes RE[TAP(C7H9S)8](acac) [RE = Nd, Eu, Y, Ho, Lu; TAP(C7H9S)8 = 2,3,7,8,12,13,17,18-octakis-(2’,4’,5’-trimethyl -3 ’-thienyl)tetraazaporphyrinato] have been prepared by treating 1,2-dicyano-1,2-bis(2’,4’,5’-trimethyl-3’-thienyl)ethane in the presence of DBU with the corresponding RE(acac)3 ? nH2O (acac = acetylacetonate) in n-pentanol. And reactions of the half-sandwich type complexes [REIII(Pc)(acac)] with 1,2-dicyano-1,2-bis(2’,4’,5’-trimethyl-3’-thienyl)ethane in the presence of DBU in n-pentanol, have led to the isolation of protonated mixed (tetraazaporphyrinato)(phthalocyaninato) rare earth double-deckersHRE[TAP(C7H9S)8](Pc) (RE = Nd, Eu, Y, Ho, Lu). http://www.chinamagnets.biz/ As far as we know, these double-deckers are the first sandwich type compounds mixing tetraazaporphyrinato and phthalocyaninato ligands, as well as the first sandwich-type bisthienylethene derivatives in the photochromic family. We managed to synthysize half-sandwich and sandwich type rare earth complexes containing tetraazaporphyrinato ligand in the ways that we usually prepare phthalocyaninato complexes. So approaches to synthesize tetraazaporphyrinato compounds have been increased. These complexes were characterized by elemental analysis and various spectroscopic methods (MS, NMR, UV-Vis, and IR). And we researched the photochromic feature of these compounds in detail. 更多还原
In Situ Assembly of Rare Earth/Polymer Luminescent Composite Material
In Situ Assembly of Rare Earth/Polymer Luminescent Composite Material
The main aim of my paper is selecting complexes with the excellent luminescent properties to develop a kind of practical rare earth polymer luminescent materials by in-situ method.In the first part, the composite material composed of the lanthanide ions and complexes doped ZnO/PEG host were prepared by sol-gel method. Sol-gel technology is the one of the most versatile methods for the preparation of inorganic-organic composites materials for its low processing temperature. In our paper, the terbium ions and four kinds of terbium complexes (The ligand of which is 2, 4-dihydroxybenzonic acid, 1, 10-phenanthroline, Acetylacetone and nicotinic acid, respectively) doped ZnO/PEG host were achieved at the room temperature, and the composite materials display Cube neodymium magnet excellent luminescent properties. As the experiment results show that adding the PEG as cover strengthens the energy transfer between the ZnO host and rare earth element without changing the crystal structure of ZnO, and the composites all emit the characteristic green luminescence of Tb3+ ion. By the same method, the composites material composed of the europium and dysprosium complexes (nicotinic acid as ligand) doped ZnO/PEG host were obtained and the samples exhibit the two kinds of lanthanide ions respective characteristic luminescence.In second part, the transparent hybrid thick films composed by [Ln-(2-HnicO)] [Ln-(2-HnicO) (phen)] (2-H2nicO = 2-Hydroxynicotinic) (Ln = Dy, Tb, Eu) and polymethyl methacrylate (PMMA) have been achieved by in-situ polymerization. The luminescence properties and energy transfer for these polymeric composite films were studied with absorption spectra, IR spectra, and http://www.chinamagnets.biz/ fluorescent emission spectra in detail. And the experiment results show all the hybrid thick films composed with dysprosium, terbium and europium coordination polymers show respective characteristic emission of the lanthanide ions, and these complexes can be dispersed in the PMMA homogeneously and they composed very uniformly to interpenetrate together. 更多还原
The main aim of my paper is selecting complexes with the excellent luminescent properties to develop a kind of practical rare earth polymer luminescent materials by in-situ method.In the first part, the composite material composed of the lanthanide ions and complexes doped ZnO/PEG host were prepared by sol-gel method. Sol-gel technology is the one of the most versatile methods for the preparation of inorganic-organic composites materials for its low processing temperature. In our paper, the terbium ions and four kinds of terbium complexes (The ligand of which is 2, 4-dihydroxybenzonic acid, 1, 10-phenanthroline, Acetylacetone and nicotinic acid, respectively) doped ZnO/PEG host were achieved at the room temperature, and the composite materials display Cube neodymium magnet excellent luminescent properties. As the experiment results show that adding the PEG as cover strengthens the energy transfer between the ZnO host and rare earth element without changing the crystal structure of ZnO, and the composites all emit the characteristic green luminescence of Tb3+ ion. By the same method, the composites material composed of the europium and dysprosium complexes (nicotinic acid as ligand) doped ZnO/PEG host were obtained and the samples exhibit the two kinds of lanthanide ions respective characteristic luminescence.In second part, the transparent hybrid thick films composed by [Ln-(2-HnicO)] [Ln-(2-HnicO) (phen)] (2-H2nicO = 2-Hydroxynicotinic) (Ln = Dy, Tb, Eu) and polymethyl methacrylate (PMMA) have been achieved by in-situ polymerization. The luminescence properties and energy transfer for these polymeric composite films were studied with absorption spectra, IR spectra, and http://www.chinamagnets.biz/ fluorescent emission spectra in detail. And the experiment results show all the hybrid thick films composed with dysprosium, terbium and europium coordination polymers show respective characteristic emission of the lanthanide ions, and these complexes can be dispersed in the PMMA homogeneously and they composed very uniformly to interpenetrate together. 更多还原
Experimental Studies on the Fluorescent Property of Optical Resin Containing Lanthanide (Europium Ⅲ) Organic Complex
Experimental Studies on the Fluorescent Property of Optical Resin Containing Lanthanide (Europium Ⅲ) Organic Complex
Compounds containing rare earth ions have long been used asfluorescent and laser materials due to their sharp intensely luminescent f-felectronic transitions. Unfortunately, since the f-f transitions of rare earthions are forbidden by the selection rule, they absorb very little excitationenergy. Photoactive rare earth organic complex exhibits intense narrowemission band via an effective intramolecular energy transfer from theligands to the metal ions under excitation by near ultraviolet light, which iscalled the antenna effect.Therefore, they are expected to be promising Block neodymium magnet luminescent dopants forthe preparation of hybrid fluorescent and other optical sources.However, most of the researches concerning lanthanide b-diketonatechelates have been mainly focused on the solid complexes themselves andthe practical applications of organic rare earth complexes are hindered bytheir weaknesses such as thermal and luminescence stability et al. A varietyof approaches have been developed to overcome the above-mentionedweaknesses and to enlarge their application range.The synthesis of polymer composite materials containing lanthanideorganic complexes is an important approach to the preparation ofphotoelectric functional materials. In the synthetic process, the partial polargroup in polymer chains is able to replace some micro-molecule ligand(such as water) in lanthanide complex occurring interaction with lanthanideion, leading to the profound effect of the structure and performance Block neodymium magnet oflanthanide polymer composite materials.In this paper, the copolymer system of styrene/α-methyl acrylic acidwhich can coordinate with lanthanide and possess polymeric activity wasselected. Novel composite resins possessing good luminescent propertieshave been synthesized through a free radical copolymerization of styrene,α-methyl acrylic acid and the binary or ternary complexes of lanthanideions (Eu3+). We characterized the molecular structure, physical andmechanical performance, and the luminescent properties of the compositeresins. Spectra investigation indicated that α-methyl-acrylic acid act asboth solubilizer and coligand. Photoluminescence measurement indicatedthat the lanthanide complexes show superior emission lines and higherintensities in the resin matrix than in the corresponding pure complexpowders (although the complex content in copolymer system is only 0.31wt%). The phenomenon can be attributed to the restriction of molecularmotion of complexes by the http://www.chinamagnets.biz/ polymer chain networks and the exclusion ofwater molecules from the complex. These results indicated that thesecomposite resins possessed better transparency (80～89%) and mechanicalperformance. The lifetime of the lanthanide complexes is lengthened whenthey were incorporated in the polymer matrix(except Eu(DBM)3CPC). 更多还原
Compounds containing rare earth ions have long been used asfluorescent and laser materials due to their sharp intensely luminescent f-felectronic transitions. Unfortunately, since the f-f transitions of rare earthions are forbidden by the selection rule, they absorb very little excitationenergy. Photoactive rare earth organic complex exhibits intense narrowemission band via an effective intramolecular energy transfer from theligands to the metal ions under excitation by near ultraviolet light, which iscalled the antenna effect.Therefore, they are expected to be promising Block neodymium magnet luminescent dopants forthe preparation of hybrid fluorescent and other optical sources.However, most of the researches concerning lanthanide b-diketonatechelates have been mainly focused on the solid complexes themselves andthe practical applications of organic rare earth complexes are hindered bytheir weaknesses such as thermal and luminescence stability et al. A varietyof approaches have been developed to overcome the above-mentionedweaknesses and to enlarge their application range.The synthesis of polymer composite materials containing lanthanideorganic complexes is an important approach to the preparation ofphotoelectric functional materials. In the synthetic process, the partial polargroup in polymer chains is able to replace some micro-molecule ligand(such as water) in lanthanide complex occurring interaction with lanthanideion, leading to the profound effect of the structure and performance Block neodymium magnet oflanthanide polymer composite materials.In this paper, the copolymer system of styrene/α-methyl acrylic acidwhich can coordinate with lanthanide and possess polymeric activity wasselected. Novel composite resins possessing good luminescent propertieshave been synthesized through a free radical copolymerization of styrene,α-methyl acrylic acid and the binary or ternary complexes of lanthanideions (Eu3+). We characterized the molecular structure, physical andmechanical performance, and the luminescent properties of the compositeresins. Spectra investigation indicated that α-methyl-acrylic acid act asboth solubilizer and coligand. Photoluminescence measurement indicatedthat the lanthanide complexes show superior emission lines and higherintensities in the resin matrix than in the corresponding pure complexpowders (although the complex content in copolymer system is only 0.31wt%). The phenomenon can be attributed to the restriction of molecularmotion of complexes by the http://www.chinamagnets.biz/ polymer chain networks and the exclusion ofwater molecules from the complex. These results indicated that thesecomposite resins possessed better transparency (80～89%) and mechanicalperformance. The lifetime of the lanthanide complexes is lengthened whenthey were incorporated in the polymer matrix(except Eu(DBM)3CPC). 更多还原
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