合金元素对HDDR工艺Nd-Fe-B合金粉显微组织和磁各向异性的影响

Effects of Alloy Elements on Microstructure and Magnetic Anisotropy of NdFeB Alloy Powders Produced by HDDR Process

研究了Ｃｏ和Ｚｒ对ＮｄＦｅＢ合金ＨＤＤＲ粉显微组织和磁各向异性的影响。磁测量结果表明，Ｎｄ１３Ｆｅ８０．４Ｚｒ０．１Ｂ６．５基本上是磁各向同性的，而Ｎｄ１５Ｆｅ６６．９Ｃｏ１１Ｚｒ０．１Ｂ７合金粉末则具有较强的磁各向异性，显微组织观察发现，退火后ＮｄＦｅＢ合金中存在一些富Ｚｒ的新相，并且这些新相在ＨＤＤＲ处理过程中并不发生变化，而Ｃｏ在一定程度上抑制了这些新相的出现，不仅减小了该相的体积份数而且降低了其中的Ｚｒ含量。分析表明，对ＮｄＦｅＢ合金化学成分进行优化以保证硬磁相内溶有一定量的合金元素（例如Ｚｒ）是获得各向异性ＨＤＤＲ粉的关键所在。

?Effects of Co and Zr additions on microstructure and magnetic anisotropy of NdFeB alloy powders produced by HDDR process were investigated. Magnetic measurements showed that the HDDRtreated powder of Nd13Fe80.4Zr0.1B6.5 alloy is nearly magnetically isotropic whereas that of Nd15Fe66.9Co11Zr0.1B7 alloy is remarkably anisotropic. Microstructural obserbvations found that a new Zrrich phase is formed in the homogenized NdFeZrB alloy and remains unchanged during the HDDR process. However, concurrent additions of Co and Zr depress the formation of the new Zrrich phase so that both its volume fraction and Zr content are reduced. These results suggest that a sufficient solubility of alloying elements such as Zr into the hard magnetic phase via the optimization of chemical composition of NdFeB alloy is the key point to the production of anisotropic NdFeB alloy powders by HDDR process.