作者:何国柱;
关键词:洁牙:6789,广厅:4385,合肥:3641,多梦:3067,切口:2631,国名:2254
单位: Nankai University,
摘要:<正> Ⅰ. INTRODUCTION The problem of focusing electron beams by periodic magnetic fields has been studied by many Neodymium Magnets
http://www.999magnet.com/products/110-sintered-neodymium-magnets authors, e.g., Brewer, Clogston and Heffner, and Mendel, Quate and Yocum. In their studies, it has been assumed that the electron beams are emerging from cathodes completely shielded from the magnetic field. Chang and Mendel have extended these studies to cover the


作者:袁重华,潘崇言,金瑞湘,吴灵葳
关键词:知心:6355,八国:5829,护国:5062
单位:Research Institute of Iron and Steel, Ministry of Metallurgy









,Research Institute of Iron and Steel, Ministry of Metallurgy









,Research Institute of Iron and Steel, Ministry of Metallurgy









,Research Institute of Iron and Steel, Ministry of Metallurgy
摘要:<正> X-ray diffraction study, together with magnetic measurements, was made on liquidphase sintered permanent magnets of the RCo_5 type (R=Sin, Sm_(0.5) Pr(0.5), or MM(0.6) Sm(0.5)). It was found that the sintered samples invariably possessed a skin layer of about 0.3 mm in thickness. This layer and the core of the sample, therefore, had te be studied separately, magnetic measurements being made only on the core. In comparison with the core, the skin layer proved to have a more complex structure. As far as composition is concerned, the akin material had a higher R-content and a lower Co-content. At an overall Co-content of about 63% by weight: the sintered core had a maximum intrinsic coercive force and exibited only a single metallic phase, i.e., the RCo_5-type intermetallic compound with CaZn_5 structure. No evidence for the presence of any R_2Co_7 or R_2Co_17 phase was detected in the diffraction patterns. The relative amount of the liquid-phase siniering aid in the mixed powder before sintering was varie


关键词:NdFeB;;rare earth permanent magnet;;microstructure
摘要:<正> An addition of Nb up to 2 at.-% into(Nd,Dy)-(Fe,Co)-B alloy causes the formation ofdendrite Fe_2Nb and the precipitates in hard magnetic grains.Both increases withincreasing Nb content.During sintering,part of Fe_2Nb dissolves within the 2:14:1 grains,and the Fe_2Nb along grain boundaries hinders the growth of 2:14:1 grains.During an-nealing,the dissolved Nb in(?)-phase precipitates out,and this nearby the grain boundarydiffuses into Nd-rich phase to form new granular Fe_2Nb and to increase the Nb contentin Nd-rich phase,this results in a precipitate-free zone in the(?)-grain near Nd-rich phase.