NdFeB铸片渗Dy工艺及其机理研究

Research on Dy diffusion process and mechanism for NdFeB strip-cast

为提高NdFeB铸片渗Dy的均匀性，将Dy2O3粉末、DyF3粉末分别与NdFeB铸片混合后分别在950℃和1050℃的高真空条件下进行渗Dy处理。通过组织观察和EDS能谱分析，讨论了渗Dy温度对组织结构和渗Dy效果的影响，并通过热力学计算分析了渗Dy反应过程。结果表明，在700～1000℃范围内，反应的吉布斯自由能为正值，无法释放出活性Dy原子，Dy没有通过渗Dy处理进入NdFeB铸片并且过高的渗Dy温度会破坏铸片的组织结构，因此在本实验条件下NdFeB铸片渗Dy工艺不可行。

In order to improve Dy homogeneity of Dy-diffusing process for NdFeB strip-cast, Dy2O3 and DyF3 powder were mixed with NdFeB strip-cast followed by heat treatment at 950℃/1050℃ under high vacuum, respectively. The influence of Dy-diffusing temperature on the microstructure and Dy diffusing effect of strip-cast were discussed via metallographic observation and EDS analysis, and reaction processes were analysed by thermodynamic calculation. The results show that the Gibbs free energy of all reactions is positive at the temperature ranging from 700℃ to 1000℃, which indicate that Dy atoms are not released in the process of the reactions. In other words, Dy element fails to diffuse into NdFeB strip-cast. It also could be found that the microstructure of strip-cast was damaged in high temperature. So the process of Dy-diffusing for NdFeB strip-cast was damaged in high temperature. So the process of Dy-diffusing for NdFeB strip-cast under condition of this experiment is not available.