目的 探究硅烷处理对阴极电泳涂层的耐腐蚀性能及其与基体间结合力的影响。 方法 对稀土镁合金表面进行硅烷前处理,再沉积阴极电泳涂层,评价涂层的耐腐蚀性能、抗溶胀性能,分析涂层的腐蚀微观形貌、组织结构及界面结合。 结果 硅烷膜层具有一定的防护性能,能够减少阴极电泳涂层针孔、橘皮的出现,增强阴极电泳涂层的致密性。 硅烷改性能够提高阴极电泳涂层与基体的结合力,硅烷预处理的电泳试样在 NMP 溶液中浸泡 102 h,依然结合完好;而未经硅烷预处理的电泳试样浸泡 7 min 后,涂层就完全剥落。 此外,硅烷处理能够极大地改善阴极电泳涂层的阻抗性能, 使涂层在 3 . 5% ( 质量分数) NaCl 溶液中浸泡 227 h 的极化电阻 R_p 仍在 10⁸数量级以上。 结论 硅烷阴极电泳复合涂层具有良好的耐蚀性能和抗溶胀性能,值得推广应用。

Objective To investigate the effect of silane treatment on the binding force and corrosion resistance of E-coating. Methods Cathode electrophoresis was applied to prepare protective coating on rare earth magnesium alloy EW75M. Corrosion resistance was evaluated by electrochemical impedance. The swelling characteristics of E-coating on magnesium alloy substrate was evaluated by NMP test. Scanning Electron Microscope ( SEM) was applied to analyze the coating corrosion microstructure and the interface bonding of coatings. Results The results showed that a transparent and thin film formed on the surface of magnesium alloy treated by silane. The film could protect magnesium alloy from corrosion. Silane film could reduce the occurrence of pinhole and orange peel on E-coating, and increase the density of E-coating. The adhesion and resistance of E-coating were improved by silane pre-treatment on Mg alloys. The silane + E-coating was intact after 102 h immersion in NMP solution, while the E-coating completely fell off after 7 min immersion. In addition, the resistance value of silane+ E-coating at low frequency remained above 10 ^{after 227 h immersion in 3. 5% NaCl solution, which indicated that the E-coating had excellent corrosion resistance. The resistance value of silane+ E-coat was about 4 orders of magnitude of E-coat. Conclusion Silane cathodic electrodeposition composite coating has good corrosion resistance and resistance to swelling properties, and is worthy of popularization and application for the future.}