6061铝合金无铬磷酸盐稀土转化膜的腐蚀性研究

摘要

测试了磷酸盐转化膜和稀土促进的转化膜在不同pH溶液中的极化曲线、时间-电位曲线和电化学阻抗谱(EIS),对磷酸盐转化膜的耐蚀性能进行了研究.电化学测试表明:稀土磷酸盐处理后的铝合金试样的阳极极化电流下降；交流阻抗测试结果显示:由稀土促进生成的磷酸盐化学转化膜具有较大的极化电阻,二者都说明经稀土促进的转化膜的耐腐蚀性能得到了加强.%The corrosion resistance of phosphate conversion coating was studied by the polarization curves, time - potential curves and electrochemical impedance spectroscopy of phosphate conversion coating in solutions with different pH values. Electrochemical tests showed that anodic polarization current of alumi num alloy treated by rare earth phosphate declined and AC impedance test results indicated that phosphate conversion coating activated by rare earth gave a large polarization resistance. Both indicated that the corro sion resistance of phosphate conversion coating activated by rare earth were enhanced.