锌镀层表面稀土转化膜成膜机理分析(Ⅰ)

Investigation on the Mechanism of Forming Rare Earth Conversion Coating on Zinc Plating

将镀锌层浸泡于以Ce(NO3)3.6H2O为主盐、以30%H2O2为氧化剂的稀土转化膜处理液中,通过计算界面上pH可达到的最大值、Ce-H2O系电位-pH图及Zn-H2O系电位-pH图,推断稀土转化膜可能是由ZnO、CeO2、Ce2O3、Ce(OH)3及Ce(OH)4构成;同时利用X射线光电子能谱仪对该铈盐转化膜表面进行成分分析,结果表明,铈盐转化膜主要是由ZnO、CeO2、Ce2O3、Ce(OH)3、Ce(OH)4构成的复合膜层,这与热力学分析计算相吻合。

A cerium conversion coating was prepared on zinc plating by chemical conversion treatment of specimens in an aqueous solution of the main salt as Ce（NO3）3·6H2O and the oxidant as 30% H2O2.The max pH of interface,Potential-pH plot of Ce-H2O and Potential-pH plot of Zn-H2O were calculated,the result inferred that the cerium conversion coating consisted of zinc oxide,cerium dioxide and hydrated cerium（Ⅲ and Ⅳ） oxide and the chemical composition of the cerium conversion coating was proved by XPS.