Al及LY12Al的表面处理与复合转化膜的耐蚀性能研究

SURFACE TREATMENT AND CORROSION RESISTANCE OF COMPLEX CONVERSION COATING FOR Al AND LY12Al ALLOY

采用失重法与电化学方法研究了纯铝及LY1 2铝合金表面钼酸盐和锰酸盐的化学复合转化膜。首先 ,在不同的钼酸盐 (锰酸盐 )钝化剂里生成Al,LY1 2Al转化膜 ,然后进行阴极和阳极极化曲线测定 ,得到一系列电化学参数。将成膜的Al,LY1 2Al浸在人造海水中观察 ,分别测试在pH =3、pH =1 3的 3 .5 %NaCl溶液中的极化曲线。结果表明 ,处理工艺简单 ,成膜速度快。铝及铝合金钼酸盐和锰酸盐的化学复合转化膜提高了耐蚀性能 ,有效地抑制了铝合金在 3 .5 %NaCl溶液中的点蚀。

The molybdate and manganate conversion coatings for aluminum and LY12 aluminum alloy were investigated using weight loss and electrochemical methods. At first, the conversion coatings of Al and LY12Al were produced in different passivators of molybdate (and manganate )and studied using cathodic polarization and anodic polarization. A serious of electrochemical parameters were obtained. The corrosion inhibition of the coated aluminum and LY12 aluminum alloy were studied in artificial ocean water. Potentiodynamic polarization curves of the molybdate and manganate complex conversion coating for Al and LY12Al were measured in 3.5%NaCl solution at pH=3 and pH=13. The experimental results show that the treating process is simple and the speed for complex coating formation is fast. The corrosion resistance of Al, LY12 alloy is increased owing to the complex conversion coatings and the pitting corrosion of Al and LY12 alloy in 3.5% NaCl solution is also inhibited efficiently, And the mechanisms of molybdates and manganate complex coating formation and corrosion resistance were analyzed.