钕铁硼磁体表面高耐蚀性锌铝涂层的制备及性能研究

Preparation of highly corrosion-resistant ZnAl coating on NdFeB magnet and study on its properties

通过浸涂-离心工艺在NdFeB磁体表面制备了ZnAl涂层,对涂层形貌、元素成分及织构进行了分析,研究了ZnAl/NdFeB磁体的极化曲线、高温老化和耐盐雾性能,测试了磁体涂覆后磁通量的变化。结果表明,NdFeB磁体表面制备的ZnAl涂层中Zn、Al以金属单质的形式存在,且以片状形态堆叠于磁体表面。涂覆后,磁体在3.5%NaCl溶液中的腐蚀电流密度降低了2个数量级。高温高湿老化400 h和中性盐雾试验720 h后,ZnAl/NdFeB磁体表面无变化。NdFeB磁体的磁通在涂覆后只降低了0.14%~0.26%,说明ZnAl涂层对NdFeB磁体的磁性能影响甚微。

A ZnAl coating was prepared on the surface of NdFeB magnet via dip coating followed by centrifugation.The surface morphology,elemental composition,and texture of the ZnAl coating were analyzed.The polarization curve,hightemperature aging,and salt spray resistance of the ZnAl/NdFeB magnet were studied.The variation of magnetic flux for NdFeB magnet before and after be coated was measured.The results showed that Zn and Al existed as metal elements in the coating and superimposed as sheets on the surface of magnet.The corrosion current density of ZnAl/NdFeB magnet was two orders of magnitude lower than that of the uncoated one in 3.5%NaCl solution.The surface of ZnAl/NdFeB magnet did not change after high-temperature and humidity aging for 400 h and neutral salt spray testing for 720 h.The magnetic flux of NdFeB magnet was reduced by 0.14%-0.26%after coating with ZnAl,indicating that the ZnAl coating has little effect on the magnetic property of NdFeB magnet.