NdFeB磁体表面致密化Ni镀层制备及其耐腐蚀性能

Study on Preparation and Corrosion Behavior of Sintered NdFeB MagnetsCoated with Densed-Ni Coatings

摘要:

采用高能球磨法实现烧结NdFeB磁体表面Ni镀层的致密化,并对致密化后Ni镀层进行膜/基结合力、维氏硬度测试,通过中性盐雾实验和高温PCT实验研究磁体的耐腐蚀性能,采用静态全浸腐蚀实验进一步分析磁体的腐蚀过程。结果显示,球磨处理工艺可以实现磁体表面Ni镀层的致密化,当转速400 rpm,球磨时间为24 h时,Ni-D24/NdFeB磁体的显微硬度由427.95 HV增加至502.67 HV,结合力由16.30 MPa提升至23.85 MPa,具有更好的耐机械损伤性能。镀层的自腐蚀电流密度较Ni/NdFeB磁体降低了1个数量级,耐中性盐雾时间由312 h提升至480 h,具有更好的耐腐蚀性能。

Abstract:

The densed-Ni coatings on sintered NdFeB magnets was prepared by high-energy ball milling method, and the densed-Ni coating was tested by film/substrate bonding force and Vickers hardness. The corrosion resistance of the magnets was studied by neutral salt spray test and high temperature PCT test. The corrosion process of the magnets was further analyzed by static full immersion test. The results showed that the Ni coating on the magnet surface could be densified by ball milling process. The microhardness of Ni-D24/NdFeB magnet increased from 427.95 HV to 502.67 HV and the binding force increased from 16.30 Mpa to 23.85 Mpa at 400 rpm and 24 h ball milling time, which indicated better mechanical damage resistance. The self-corrosion current density of the coating reduced by one order of magnitude compared with that of Ni/NdFeB magnet, and the resistance time to neutral salt spray increased from 312 h to 480 h, showing better corrosion resistance.