烧结NdFeB微观组织在自来水中的腐蚀研究

Research on the Erosion of the Microstructure of Sintered NdFeB in Tap Water

烧结NdFeB磁体由于富含活泼稀土元素Nd、Dy等而易于被腐蚀,从而使其应用受到影响。酸、碱、盐,甚至自来水都会损害其微观组织。试验采用SEM、金相显微镜等对比研究了NdFeB磁体被自来水腐蚀前后的情况。结果发现,在自来水中浸泡数秒钟,样品表面的腐蚀就非常剧烈,金相照片中已经看不到富Nd像的存在,晶界亦不明显;时间延长至1h,样品表面会出现一定的锈斑;浸泡1d以上时,样品表面还会出现腐蚀坑。

Some lively elements, such as Nd, Dy, in the sintered NdFeB magnet make it easily eroded, which will affect its application. Some substance, such as acid, alkali, salt, even tap water, etc. may erode its microstructure. A eontrastive study has been made on the tap - water - eroded sintered NdFeB by SEM and metallographieal microscope. The result shows that there are not rich Nd phase and crystal - bound on the surface of rusted sintered NdFeB magnet after several minutes in the tap water. When dipped for an hour in the tap water, there are rubiginous spots, and after an hour, there are rubiginous holes.