利用极化曲线方法,研究了以 La ( NO₃)₃ ·6 H₂O 为促进剂的磷酸盐转化膜的耐蚀性,同时与铬磷化膜及无稀土促进的单纯磷酸盐膜的耐蚀性进行了对比;通过划格法和全浸腐蚀试验,研究了这三种转化膜与有机涂层间的结合力。 结果发现:与单纯磷酸盐膜相比,稀土促进生成的磷酸盐膜中的传输阻力增加,耐蚀性明显增强,而与铬磷化膜相比,二者在弱极化区的耐蚀性能相近;稀土促进生成的磷酸盐膜与有涂层间的结合力明显优于铬磷化膜。

The anti-corrosion of the conversion coating which is formed by La( NO₃)₃ ·6 H₂O was evaluated with polarization curve, and also compared the chromium phosphate film and non-rare phosphate conversion coating. Adhesion force between the conversion coatings and the organic coating were studied through crossing grid method and immersing corrosion test .The results showed that the transmission resistance of conversion coating with rare earth additive was increased by comparing with non-rare phosphate conversion coating; The anti-corrosion of the conversion coating was increased noticeably. But comparing with chromium phosphting, in the weak polarized scope, both of the corrosion resistances were close. Adhesion force between the conversion coating with rare earth as additive and the organic coating was obviously superior to that of chromate phosphate process.