快淬Nd-Fe-B磁粉表面的包覆工艺

Surface Treatment of Rapidly Quenching Nd-Fe-B Magnetic Powder

快淬 Nd- Fe- B粘结磁粉极易发生氧化和腐蚀 ,导致粘结磁体性能降低 .为此 ,采用重铬酸盐钝化工艺、硅烷耦联剂包覆工艺、重铬酸盐钝化还原工艺以及重铬酸盐钝化还原 -硅烷复合包覆工艺对 Nd- Fe- B磁粉进行表面包覆 ,并采用热氧化增重实验及差示扫描量热分析仪测定包覆处理前后快淬 Nd- Fe- B磁粉的抗氧化性能 ,进而比较各种表面处理工艺的优劣 .结果表明 ,上述工艺方法均能改善 Nd- Fe- B磁粉的抗氧化性 ,其中以硅烷耦联剂处理工艺、重铬酸盐纯化还原

The powders from rapid quenched NdFeB are extremely easy to be oxidized and corroded. It deteriorates the magnetic properties of the bonded magnets. The NdFeB powders are covered using dichromate passivation technology, silicon alkane covering technology, dichromate passivation reducing technology and dichromate passivation reducing plus silicon alkane covering technology. The oxidation resistance of the powders from rapid quenched NdFeB before and after covering is measured here using oxidation and weight increasing method, differential scanning calorimeter (DSC), and the different technologies are compared. It is shown that the oxidation resistance of the best one of them is the silicon alkane covering technology and dichromate passivation reducing plus silicon alkane covering technology.