Abstract In this article, a novel chromium-free passivation agent contained sodium molybdate, sodium citrate, sodium phosphate, tannin, 1-hydroxyethylidene-1, 1-diphosphonic acid (HEDP) and cobalt nitrate was prepared. The component content of the chromium-free passivation agent was firstly determined by using the single variable method, and then optimized by the orthogonal array method. The results indicated that the optimal content of the passivation agent are sodium molybdate 15 g/L, sodium citrate 15 g/L, sodium phosphate 25 g/L, tannin 13 g/L, HEDP 14 ml/L and cobalt nitrate 11 g/L. In the neutral salt spray test, the corrosion life of the as-prepared passivation coatings can reach 46 h, implying the potential commercial application of this chromium-free passivation agent.

中文翻译：

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用于碳钢多色镀锌的新型无铬钝化剂

摘要 本文制备了一种由钼酸钠、柠檬酸钠、磷酸钠、单宁、1-羟基亚乙基-1,1-二膦酸(HEDP)和硝酸钴组成的新型无铬钝化剂。无铬钝化剂的组分含量首先采用单变量法测定，然后采用正交阵列法进行优化。结果表明，钝化剂的最佳含量为钼酸钠15 g/L、柠檬酸钠15 g/L、磷酸钠25 g/L、鞣质13 g/L、HEDP 14 ml/L和硝酸钴11 g/ L。在中性盐雾试验中，所制备钝化涂层的腐蚀寿命可达 46 小时，表明这种无铬钝化剂具有潜在的商业应用价值。