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硅烷和磷化预处理后采用阴极电泳技术在AZ31B镁合金表面制备有机涂层,并与传统喷漆涂层性能进行对比。测试了涂层的硬度,结合力及耐冲击性能。采用盐水浸泡、盐雾试验及阻抗谱测试(EIS)研究了涂层的耐腐蚀性能。利用扫描电镜分析了涂层的表面形貌。结果表明,硅烷和磷化处理均有助于提高电泳涂层与基体的结合力,阴极电泳涂层的综合机械性能要优于喷漆涂层。硅烷处理后电泳试样盐水浸泡24 h后,低频阻抗值达到109Ω,远远高于磷化处理后电泳及传统喷漆试样,其耐腐蚀性能更好。盐雾试验结果表明,硅烷处理后电泳试样1 000 h表面无变化,其耐腐蚀性能最佳。
After silane and phosphating pretreatment, cathodic electrophoresis was used to prepare the organic coating on the surface of AZ31B magnesium alloy and compared with the performance of traditional spray coating. The hardness, adhesion and impact resistance of the coatings were tested. The corrosion resistance of the coating was studied by salt water immersion, salt spray test and impedance spectroscopy (EIS). The surface morphology of the coating was analyzed by SEM. The results show that both silane and phosphating treatment can help to improve the binding force between the electrophoretic coating and the matrix. The mechanical properties of the cathodic electrodeposition coating is better than the spray coating. After immersed in saline solution for 24 h, the low frequency impedance reached to 109Ω, which was much higher than that of phosphated electrophoresis and traditional sprayed samples, which showed better corrosion resistance. Salt spray test results show that the silane treated electrophoresis sample 1000 h surface no change, the best corrosion resistance.