铝表面非铬化学转化膜的成膜工艺

Process for Fabrication of Non-Chromium Chemical Conversion Coating on Surface of Aluminum

为了开发一种无铬环保型铝材表面处理技术,在铝材表面处理液中引入了锆离子和铈离子,并加入氟离子、铝盐和双氧水等,通过正交试验优化出了一种环保型铝材非铬酸盐成膜工艺。所得最佳工艺参数:硫酸34mL/L(1∶2),12g/L硫酸铈,6g/L明矾,15g/L四氟化锆,6g/L氟硼酸钾,15mL/L双氧水(1∶2),处理温度40℃,时间20min。结果表明,新工艺可于40℃、20min内在铝材表面形成均匀、致密、抗腐蚀性强的化学转化膜。静电喷涂后的涂层附着力达0级或5B级,抗冲击试验达500N.cm,可用以代替传统的、毒性较大的铬酸盐转化膜。

Zr4+ and Ce4+ ions,together with Fions,Al salt,and H2O2 were introduced into the fluid for surface treatment of Al material to develop a process for the preparation of environmentally acceptable non-Cr chemical conversion coating.The optimized process was established based on orthogonal tests,and the optimal parameters were determined as well.Results indicated that the optimal composition of the fluid was as follows:34 mL sulfuric acid(1∶2),12 g cerium sulfate,6 g ammonium aluminum sulfate,15 g ZrF4,6 g potassium fluoroborate,15 mL H2O2.The optimized parameters were determined as a temperature of 40 ℃ and coating deposition time of 20 min.It is feasible to prepare uniform and compacted chemical conversion coating with good corrosion resistance on the surface of Al material by using the fluid with optimized composition and at optimal parameters.The resulting coating showed an adhesion force of 0 grade or 5B grade and an impact resistance of 500 N cm after static spraying,and it could be used to replace conventional toxic conversion coating of chromate.