Research On HD And HDDR Process Of NdFeB Permanent Magnet Production

This paper introduces the HD (Hydrogen-Decrepitation ) and the HDDR ( Hydrogenation-Decomposition-Desorption-Recombination ) processes of high magnetic performance NdFeB permanent magnet production, then take the experiment of the processes. The results confirm the best parameter of the HD process, and also insure the feasibility of producing high anisotropy ternary NdFeB magnetic powders for bonded magnet by adjusting parameter of HDDR process.Experiment results show, in the HD process, the temperature of dehydrogenation process sets at about 580℃, can make the hydrid of Nd complete turning into NdH₂ which can resist being eroded and oxidation, so it increases the resistance to oxidation of the magnet powders. In the dehydrogenation process of HD process, the temperature set at 580℃ and pressure set at 100Pa is a perfect parameter, it can make the magnet to have high magnetic performance. In the HDDR process experiment, the paper contrast four HDDR process such as C-HDDR V-HDDR V-HD-S-DR and d-HDDR by the anisotropy and magnetic performance of ternary NdFeB magnetic material. The results show that adjusting the parameter of the d-HDDR process can make the anisotropy and magnetic performance of ternary NdFeB magnetic powders to catch up with the hexahydric NdFeBCoZrGa magnetic powders. At the end the paper discusses the betterment of the equipment which produces ternary NdFeB magnetic with the d-HDDR process.In the end, paper discusses the security of using hydrogen in the hydrogenation process of NdFeB permanent magnet production, and votes seven advices, and then, paper discusses the economical providing method of hydrogen to production.