摘要
传统的铬酸盐处理使铝合金表面具有很好的装饰性,但六价铬由于致癌毒性被禁止使用。开发了一种环境友好的替代工艺技术。采用无毒高锰酸钾、过硫酸钠、氟化钠和添加剂,在pH11.60～11.75,常温,成膜时间为5min的条件下进行转化处理,在铝合金表面制备了金黄色无铬转化膜。通过研究转化液组成和操作条件对转化膜着色和耐蚀性的影响,优化了最佳处理工艺。通过中性盐雾试验、扫描电镜和EDS分析了膜的外观、耐蚀性、形貌和组成。研究结果表明:采用该工艺可获得颜色亮丽的金黄色转化膜,该转化膜能耐盐雾试验144h以上,室内大气环境暴露放置90d不褪色。
Aluminum alloy with traditional chromate treatment had good decoration,but hexavalent chromium is banned to use due to its carcinogenesis. An environmentally friendly alternative technology has been developed. Non-toxic potassium permanganate,sodium persulfate,sodium fluoride,additive were used to prepare a golden-yellow chromium-free conversion coating on aluminum alloy under the condition of pH 11.60-11.75,room temperature and 5 miniutes. The effects of solution composition and operation condition on coloring and corrosion resistance of conversion coating were studied experimentally for optimal the process. The conversion coating appearance,corrosion resistance,surface morphology and element constituents were analysed through neutral salt spray test,SEM and EDS. The results showed that the process could obtain a bright golden yellow conversion coating. The conversion coating could withstand more than 144 hours of neutral salt spray test and did not fade after 90 days indoor exposure.
基金
高等学校博士学科点专项科研基金资助项目(20096120110007)
陕西省自然科学研究计划资助项目(SJ08-ZT05)
关键词
铝合金
金黄色转化膜
无铬
耐蚀性
aluminum alloy
a golden-yellow conversion coating
chromium-free
corrosion resistance
