材料期刊网

采用电化学测试和扫描电镜等方法研究了硝酸铈对6061 铝合金磷化过程及磷化膜形貌的影响。结果表明，硝酸铈的加入改变了铝合金基体与磷化液之间液固界面间的初始电位；硝酸铈吸附在铝合金表面上形成凝胶，成为磷酸盐晶体形成的良好晶核，磷化晶粒细化，生成较为致密的磷化膜，膜的耐蚀性得到提高。硝酸铈使铝合金达到最高电位的时间缩短，阴极极化电流密度增大，磷化速度加快。硝酸铈在整个铝合金磷化过程中起到了成核和促进的作用。在本实验条件下，最佳硝酸盐含量为20 mg/L～40 mg/L。

The effect of cerium nitrate on the phosphating process and the phosphate coating morphology of 6061Al alloy was investigated by electrochemical measurements and scanning electron microscopy. The addition of cerium nitrate changed the initial potentials of interface between aluminum alloy substrate and phosphating solution. Cerium nitrate was adsorbed on the surface of aluminum substrates to form gel. These gel particles were good crystal pits to form phosphate crystal grains and acted as nucleation agent, resulting in phosphate crystal grains to be fined, phosphate coating to be compacted and the corrosion resistance of coating to be improved. Cerium nitrate made time shortened at which the highest potential value of aluminum alloy was achieved, the current density of cathodic polarization was increased and phosphating velocity was expedited. Cerium nitrate acted as nucleation agent and accelerator in whole phosphating process of aluminum alloy. Under this experimental condition, the optimal content of REN is 20 mg/L-40 mg/L.