铝合金红色Zr-Se化学转化膜的制备及性能研究

Preparation and Characterization of Zr-Se Based Conversion Coatings on Aluminum Alloy

为了开发一种耐蚀性优异、表面带颜色且与漆膜结合力良好的铝合金化学转化技术,在室温条件下采用氟锆酸钾和二氧化硒为主盐,在6063铝合金表面制得了红色的Zr-Se化学转化膜。利用电化学工作站、能谱仪(EDS)和X射线光电子能谱仪(XPS)、扫描电子显微镜(SEM)、点滴试验、划格试验等对转化膜的耐蚀性、成分结构和表面形貌等进行了测试表征,同时对转化膜的成膜机理进行了分析。结果表明:转化处理后铝合金的自腐蚀电流密度远小于未经过转化处理的铝合金的。铝合金红色转化膜层主要是由Na3AlF6、ZrO2、Se和复杂的有机螯合物等构成,说明制备出的转化膜层是一个高度异构的复杂系统。铝合金表面转化膜呈椭圆形,均匀致密,有利于增大膜层和漆膜的结合能力。转化膜耐蚀性与传统的铬酸盐转化膜较为接近;转化处理后的铝合金与清漆具有良好的结合能力。

In order to develop a technique to prepare the chemical conversion coating with excellent corrosion resistance,colors and adhesion,zirconium salt and Se O2 were used as the main salt under room temperature to obtain red Zr-Se conversion coating on 6063 aluminum alloy.The electrochemical workstation,energy dispersive spectrum(EDS),X-ray photoelectron spectrometer(XPS),scanning electron microscope(SEM),dropping test and other methods of analysis were employed to test the corrosion resistance,composition and surface morphologies of coatings.In addition,the formation mechanism of the aluminum alloy Zr-Se conversion film was analyzed.Results showed that the corrosion current density of aluminum alloy with transformation treatment was far less than that of sample without the conversion treatment.The main components of Zr-Se conversion coating on magnesium alloy surface were Na3AlF6,ZrO2,Se and complex organic chelates,which indicated the prepared conversion coating was a kind of high-heterogeneous complex system.Moreover,many elliptical particles were evenly attached on the surface of aluminum alloy,which could promote the binding capacity of the coating and film.Furthermore,the corrosion resistance of the conversion coating was close to that of the traditional conversion coating,and the aluminum alloy after conversion treatment possessed a good adhesion ability with varnish.