铸铝环保型转化膜耐蚀性的研究

Study on Corrosion Resistance of Environmental-Friendly Conversion Coating for Cast Aluminum

通过点滴试验比较了铸铝基体上Mo盐转化膜、Co盐转化膜、Co-Mn复合盐转化膜及硫酸阳极氧化膜的耐蚀性。结果表明:三种化学转化膜均完整、连续,但结构疏松,其中Mo盐转化膜的耐蚀性最差;而硫酸阳极氧化膜呈均匀的块状组织,结构致密,其耐蚀性最好。三种化学转化膜目前均只适用于涂装打底。后续新型环保转化液的开发集中在主盐复配、氧化剂复配等方面,有望改善膜层的耐蚀性。

The corrosion resistance of Mo salt conversion coating,Co salt conversion coating,Co-Mn compound salt conversion coating and sulphuric acid anodic oxide coating was studied by dropping test.The results showed that three kinds of chemical conversion coatings were complete and continuous,but the structure was loose.The corrosion resistance of Mo salt conversion coating was the worst.The sulphuric acid anodic oxide coating has uniform block structure and compact structure, its corrosion resistance was the best.At present,all three kinds of chemical conversion coatings were only suitable for priming.In the future,the development of new environmental-friendly conversion solution was focused on the compound of main salt and oxidant,which was expected to improve the corrosion resistance of the film.