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以硅烷为粘接剂、片状锌、铝粉为原料,采用喷涂方式在NdFeB基体上制备了环境友好型无铬Zn-Al涂层。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)对涂层的相结构及形貌进行表征,采用中性盐雾试验(NSS)和电化学方法分析镀层的耐蚀性能和耐蚀机理,用拉力试验测试涂层结合力。结果表明,Zn-Al涂层呈鳞片状,均匀致密地涂敷于NdFeB磁体表面,涂层厚度约27μm,涂层与基体结合力可达10.95 MPa。Zn-Al对NdFeB基体起到阳极保护的作用,且涂层片状结构延长了腐蚀介质的腐蚀通道,涂层NSS测试可达600 h以上,远远超过传统电镀Zn层的耐中性盐雾能力。
An environment-friendly chrome-free Zn-Al coating was prepared on NdFeB matrix by using silane as binder, flake zinc and aluminum powder as raw materials. The phase structure and morphology of the coating were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The corrosion resistance and corrosion resistance of the coating were analyzed by neutral salt spray test (NSS) and electrochemical method The tensile test was used to test the coating adhesion. The results show that the Zn-Al coating is flake-like and uniformly densely coated on the surface of NdFeB magnet. The coating thickness is about 27μm, and the bonding strength between the coating and the substrate is up to 10.95 MPa. Zn-Al plays an anode protection role on the NdFeB matrix, and the coating sheet-like structure prolongs the corrosion channel of the corrosive medium. The coating NSS test can reach more than 600 h, which far exceeds that of the conventional electroplated Zn layer ability.