摘要
目的研究铝合金表面非铬酸盐高耐蚀性转化膜的制备工艺。方法以K2Zr F6和K2Ti F6为主盐,KMn O4为氧化剂,Na F为成膜促进剂,在5052铝合金表面制备化学转化膜。采用SEM,EDS,FT-IR,XPS对转化膜的形貌、结构以及成分进行分析,通过硫酸铜点滴实验、全浸蚀实验和极化曲线对转化膜的耐蚀性进行研究。结果获得了土黄色转化膜,主要由Al F3·3H2O,Al Ox/Al,Al2O3,Mn O2和Ti O2组成。转化处理后,铝合金的腐蚀电位正移了约591 m V,腐蚀电流密度由1.10μA/cm2降低为0.48μA/cm2。经过封闭处理后,腐蚀电流密度降低为0.04μA/cm2,耐蚀性明显提高。结论以K2Zr F6和K2Ti F6为主盐在铝合金表面形成的土黄色化学转化膜具有良好的耐蚀性。
Objective To study the preparation process of the chromate-free conversion treatment on aluminum alloys. Methods The chemical conversion coating was prepared with K2 ZrF6 and K2 TiF6 as the main salt, KMnO4 as the oxidant and NaF as the ac-celerant. The surface morphology, structure and composition were analyzed by SEM, EDS, FT-IR, and XPS. The corrosion resist-ance of conversion coating was studied by copper sulfate dropping, salt water immersion and polarization curve. Results The pre-pared yellow conversion coating mainly consisted of AlF3 ·3H2 O, AlOx/Al, Al2 O3 , MnO2 , and TiO2 . The corrosion potential of the Al alloy sample was positively shifted about 591 mV and the corrosion current density was dropped from 1. 10 μA/cm2 to 0. 48μA/cm2 after conversion treatment. After sealing treatment, the corrosion current density further decreased to 0. 04 μA/cm2 and the corrosion resistance was significantly improved. Conclusion The conversion coating, which was prepared with K2 ZrF6 and K2 TiF6 as the main salt, had good corrosion resistance.
出处
《表面技术》
EI
CAS
CSCD
北大核心
2015年第5期38-42,共5页
Surface Technology
关键词
铝合金
转化膜
封闭处理
耐蚀性
aluminum alloy
conversion coating
sealing treatment
corrosion resistance
