It was of great significance to the efficient formation of rare earth conversion coating with high corrosion resistance by using chemical immersion method through the addition of oxidant and promoter of coating-formation for the preparation of rare earth conversion coating on the surface of zinc plating. The results show that through the electrochemistry test, morphology analysis and dynamics data calculation, reductive reaction at micro-cathode is speeded up by the addition of oxidant H2O2 into the treatment solution, and promoting the increase of Ph within the micro-cathode region, which is favorable to the formation of conversion coating with high content of Ce. The addition of coating-formation promoter can improve the shape quality of the coating, whose essence is to lower effectively the apparent activation energy for coating-formation reaction with three stages,giving rise to the realization of promotion for conversion coating's growing.%采用添加氧化剂和成膜促进剂的化学浸泡法在电镀锌层表面制备稀土转化膜,氧化剂和成膜促进剂的加入,对有效形成高耐蚀性的稀土转化膜起到了至关重要的作用.通过电化学测试、形貌分析以及动力学数据计算,结果表明:H<,2>O<,2>作为氧化剂加入到处理液中,一方面可加快微阴极发生还原反应,另一方面通过发生H<,2>O<,2>的还原反应,促进微阴极区pH上升,有利于形成富含铈的转化膜;成膜促进剂的加入可改善膜层的外观质量,其加入的实质是通过有效降低成膜三个反应阶段的表观活化能,从而实现对转化膜生长的促进.
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