PASSIVATION PROCESS OF STEEL TINPLATE

The present invention relates to a passivation process of a steel tinplate, and especially relates to a Cr-free passivation process of the tinplate. The method comprises the following steps in sequence: a. subjecting said tinplate to at least one cathodic electrolytic treatment in an aqueous solution containing at least one sulphate of an alkali metal to obtain a tin oxide surface layer having thickness lower than 6 mC/cm ; b. subjecting said tinplate to at least one cathodic electrolytic treatment in an aqueous solution containing at least sulphate ions and zirconium ions to form a passivation layer containing zirconium on said tin oxide surface layer. The process allows obtaining the passivated tinplate on which the coatings, such as enamels, paints and polymeric films, adhere well, without using chromium-containing compounds. 本发明涉及镀锡钢板的钝化工艺。特别地，本发明涉及镀锡板的不含Cr钝化工艺，其按顺序包括以下步骤：a.使所述镀锡板在含有至少一种碱金属硫酸盐的水溶液中经受至少一次阴极电解处理以获得具有小于6mC/cm的厚度的锡氧化物表面层；b.使所述镀锡板在含有至少硫酸根离子和锆离子的水溶液中经受至少一次阴极电解处理以在所述锡氧化物表面层上形成含有锆的钝化层。该工艺允许在不使用含铬