氢对Nd-Dy-Fe-B磁体制作过程的影响

Effect of Hydrogen on the Process of Nd-Dy-Fe-B Magnets

研究了氢对Nd-Dy-Fe-B磁体制作过程的影响,主要包括氢对HD磁粉的氧化和对其后烧结磁体磁性能的影响。研究表明,氢不利于HD磁粉的氧化稳定性能,氢的存在促进磁粉吸湿和电化学腐蚀,加快氧的扩散。HD磁粉经过在一定温度下真空脱气处理后,氧化稳定性提高,特别是在较高温度下进行脱气处理的磁粉。氢的存在使磁粉容易粉碎,加快磁体的烧结过程,降低磁体的烧结温度。同时发现,未脱氢磁体的取向度较低。

Hydrogen Decrepitation (HD) has been used as an efficient and economical method in producing coarse NdFeB powder. This article studied the effects of hydrogen on the Nd-Dy-Fe-B magnets, such as HD powder oxidation and magnetic performance of sintered magnets. The results showed that the hydrogen accelerated the oxidation of the coarse Nd-Dy-Fe-B powder after HD process, and the dehydrogenated powder had higher oxidation resistance, especially degassed at higher temperature, and the hydrogen dropped the sintering temperature of Nd-Dy-Fe-B magnets. The effects of hydrogen may focus on that hydrogen bonds accelerate absorption of water from ambient air, and the defects caused by hydrogen induce oxygen diffusing more quickly. The magnets could be sintered at a lower temperature with undehydrogenated HD powder, but had poorer orientation degree.