AA6063铝合金着色Zr无铬转化膜及其电化学性能

Synthesis of Chrome-free Coloring Conversion Coating on AA6063 Aluminium Alloy and Its Electrochemical Properties

以锆盐为主要原料,实现常温下对AA6063铝合金的无铬化学转化处理。采用SEM,XRD及电化学测试研究了转化膜的性能。结果表明:锆膜生长是以针状小单元结构组织成圆形较大的单元,再发展为均匀的黑灰色转化膜;锆膜厚约8.79μm,主要由KZrF_3(OH)_2·H_2O及KZrF_3O·2H_2O组成;锆膜耐腐蚀性能比铝合金提高了数百倍,与铬酸盐转化膜相当;锆膜的耐腐蚀性能与后处理工艺有一定关系,膜层结构等效电路为R_1+C_2/R_2+M_3。

The zirconium salt as main raw materials,chrome-free chemical conversion treatment was carried out on AA6063 aluminium alloy at room temperature.Through the analysis of SEM,XRD and electrochemical test,the properties of the chrome-free conversion coating were studied.The results show that zirconium coating grows from needle like small cell structure to large round cell,and then develops to uniform black and grey conversion coating;the thickness of zirconium coating is about8.79μm,which is mainly composed of KZrF_3（OH）_2·H_2O and KZrF_3O·2H_2O;the corrosion resistance of the zirconium coating is improved by hundreds times than aluminium alloy,and is equivalent to chrome conversion coating;the corrosion resistance of zirconium coating has a certain relationship with post treatment process,the coating structure equivalent circuit is R_1＋C_2/R_2＋M_3.