The HD and HDDR processes in the production of Nd-Fe-B permanent magnets
The HD and HDDR processes in the production of Nd-Fe-B permanent magnets
复制标题
DOI：
10.1016/s0360-3199(96)00174-7
复制
发表时间：
1997-02
影响因子：
7.2
通讯作者：
O. Ragg;G. Keegan;H. Nagel;I. R. Harris
中科院分区：
文献类型：
--
作者：
O. Ragg;G. Keegan;H. Nagel;I. R. Harris
本文介绍了一个欧盟资助的项目，以开发和放大的氢化，结晶，解吸和重组（HDDR）过程中所做的工作。本文综述了氢爆法（HD）和HDDR法，指出HD法具有相当大的经济效益，HDDR法的复合阶段是关键，但可以与结晶阶段分开。将材料长时间保持在极化状态增加了HDDR材料的极化率，并且这种改善随时间呈指数衰减。研究还表明，在歧化过程中提高温度可以改善HDDR材料的环形状和剩磁，而在歧化过程中降低氢压可以降低反应的时间依赖性，从而缩短加工时间。
This paper describes work done on an EC-funded project to develop and scale up the hydrogenation, disproportionation, desorption and recombination (HDDR) process. The hydrogen decrepitation (HD) and HDDR processes are summarized together with earlier work showing that the HD process has considerable economic advantages and the recombination stage of the HDDR process is critical, but that it may be separated from the disproportionation stage. Holding the material for extended times in the disproportionated state increases the coercivity of the HDDR material and this improvement tails off exponentially with time. It is also shown that raising the temperature during disproportionation improves the loop shape and remanence of the HDDR material whilst reducing the hydrogen pressure during disproportionation reduces the time dependence of the reaction, allowing much shorter processing times.