硝酸镧掺杂对6061铝合金表面硅烷膜耐蚀性能的影响

为改善铝及铝合金的表面防腐蚀性能,在γ-(2,3-环氧丙氧)丙基三甲氧基硅烷(KH-560)基础溶液中添加不同含量的硝酸镧,在6061铝合金表面制备不同硝酸镧浓度掺杂的硅烷-镧盐复合膜;采用极化曲线、硫酸铜点滴、腐蚀失重率试验等方法分析膜层性能,并得出了镧盐最佳用量。对比分析了最佳镧盐用量下复合膜、硅烷膜和稀土转化膜的耐蚀性能。结果表明:在KH-560硅烷膜制备过程中添加一定量硝酸镧可有效提高硅烷膜的耐蚀性,添加15 g/L硝酸镧时,形成的复合膜层致密且没有裂纹,耐蚀性最好;与单一的硅烷、镧盐转化膜相比,复合膜表现出很好的耐蚀性。

Effect of Lanthanum Nitrate Modification on Corrosion Resistance of Silane Film on 6061 Aluminum Alloy

By adding different concentrations of lanthanum nitrate into γ-(2,3-epoxypropoxy) propyltrimethoxysilane (KH560) based solution,the KH560/lanthanum salt composite films modified with different concentrations of lanthanum nitrate were prepared on 6061 aluminum alloy.The performances of film were analyzed by polarization curve measurement,dipping test of copper sulfate and test of corrosion weight-loss rate,and the optimal dosage of lanthanum nitrate was obtained.Moreover,the corrosion resistances of composite film,silane film and rareearth conversion coating were compared and analyzed.Results showed that adding a certain dosage of lanthanum nitrate into the synthesis process of KH-560 silane film could effectively improve the corrosion resistance of silane film,and when the dosage of lanthanum nitrate was 15 g/L,the prepared composite film was dense and no crack existed on the surface,which presented the optimal corrosion resistance.Compared with the silane film and rare-earth conversion coating,the composite film showed better corrosion resistance.