The Effect Of Processing On Sintering NdFeB Permanent Magnetic Material With High Coecivity

Since 1983, the technology of sintered NdFeB is gradually perfect, and its application is comparatively far-ranging. But many domestic companies yet face to the difficulties of the behindhand processing and performance, the low applying temperature. So, in these days, the researching focus is magnets with high Hcj, Br and (BH)m. One of means of increasing applying temperature may resort to increase its Hcj. Thereby, on the condition of additive proper alloy element, it is necessary to improve on the processing. To increase Hcj of the sintered NdFeB permanent magnetic material, Some processing, such as ball milling, molding, sintering and tempering, were systemically researched by NdxDyyB1.05Fe98.225-x-yGa0.3Al0.4Cu0.025 alloy and ball-milling machine, molding machine, sintering furnace, AMT-4 magnetic characteristic automatic testing apparatus, the metallography microscope, the X-ray diffraction(XRD), the scan electronic microscope(SEM), et al. The results can be summarized as follows:The general magnetic performance of sample with HD processing powder is better than that of sample without HD processing powder. The Br and (BH)m of sample with HD processing powder are good, but Hcj is bad. The performance of sample with coarse powder is pour, and testing curse is also worse. The performance of sample with more coarse powder is worse. But their performance could be increased by ameliorated processing unless there are too coarse powder.It is necessary that the magnets are aligned before molding processing. All performance but coecivity is good if it is aligned. The coecivity of sample without magnetic aligning before molding processing is better.The sample sintered in the argon is not proof-oxygen and erode, and must be plated nickel or zinc before it is used. But the sample sintered in vacuum is...