铝合金高耐蚀无铬钝化工艺

High Corrosion Resistant Non-Chromium Passivation Process of Aluminum Alloys

为开发一种高耐蚀且钝化膜具导电性的无铬钝化工艺,以锆酸盐为主要成分,加入铜盐混合促进剂和钒盐填充剂,开发了一种2A12铝合金高耐蚀无铬钝化工艺,并对钝化液成分及钝化工艺参数进行了优选,得出较优的工艺规范如下:2.0 g/L锆酸盐,0.2 g/L铜盐混合促进剂,0.1 g/L钒盐填充剂,4.5 g/L配位剂,3.0~6.0 g/L p H值缓冲剂,pH值4.0,温度55℃,时间8 min。对最佳工艺所得钝化膜的形貌及综合性能进行了分析,结果表明:所形成的钝化膜呈淡白色,结晶均匀细致,属于无裂纹的无定型结构转化膜,具有良好的耐蚀性、导电性、涂层附着力,适用于铝合金表面防护层、喷涂底层和电子产品外壳的电磁屏蔽防护层。

A non-chromium passivation process for aluminum alloy was investigated by using zirconate as the main component and adding copper salt mixed accelerator and vanadium salt filler.The process specifications were as follows:2.0 g/L zirconate,0.2 g/L copper salt mixed accelerator,0.1 g/L vanadium salt filler,4.5 g/L complexing agent,3.0-6.0 g/L p H buffer,p H value 4.0,temperature 55℃,duration 8 min.Results showed that the passivation film had uniform and fine crystallization as well as pale white.Moreover,it had good corrosion resistance,conductivity and adhesion.It was suitable for the electromagnetic shielding protective coatings on the surface of aluminium alloy,spraying bottom layer and the shell of electronic products.Therefore,it had broad application prospects.