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钼酸盐钝化能够显著提高镀锌层的耐腐蚀能力。一定工艺下获得的钼酸盐钝化膜的耐蚀性与铬酸盐钝化膜的耐蚀性相当 ,在酸性腐蚀介质下甚至可优于铬酸盐钝化。钼酸盐钝化膜中存在裂纹会降低钝化膜在中性盐雾腐蚀或盐水浸泡腐蚀中的耐蚀能力 ,而在酸性盐雾腐蚀下钝化膜的耐蚀能力则主要取决于钝化膜厚度。钼酸盐钝化膜能阻滞锌层在 5 %NaCl水溶液中腐蚀的阴极过程 ,使腐蚀电流显著减小
Molybdate passivation can significantly improve the galvanized layer corrosion resistance. The corrosion resistance of the molybdate passivation film obtained under a certain process is comparable to that of the chromate passivation film and even better than the chromate passivation under acidic etching media. The presence of cracks in the molybdate passivation film will reduce the corrosion resistance of the passivation film in neutral salt spray corrosion or salt immersion corrosion, whereas the corrosion resistance of the passivation film depends mainly on passivation Film thickness. The molybdate passivation film can block the cathodic process of the zinc layer from corroding in 5% NaCl aqueous solution, resulting in a significant reduction of the corrosion current