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将热浸镀锌钢浸渍在20 g·L~(-1)Ce(NO_3)_3·6H_2O溶液(pH=4,25℃)中10s~24 h,制备了铈盐转化膜试样。通过中性盐雾和盐水浸泡试验评价了转化膜在含Cl~-介质中的耐蚀性能。采用扫描电镜和X射线衍射能谱研究了转化膜的形貌和物相结构。结果表明,铈盐转化膜能显著推迟热浸镀锌层出现白锈的时间;随成膜时间的延长,转化膜的耐蚀性能先增加后下降;当成膜时间为30~60 min时,转化膜的耐蚀性能最佳。铈盐转化膜主要由非晶态结构的ZnO和CeO_2组成,在腐蚀介质中不易形成腐蚀微电池。
The samples of cerium conversion coating were prepared by immersing hot dip galvanized steel in 20 g · L -1 Ce (NO_3) _3 · 6H_2O solution (pH = 4, 25 ℃) for 10s ~ 24 h. The corrosion resistance of the conversion coating in Cl ~ - media was evaluated by neutral salt spray and brine immersion test. The morphologies and phase structures of the conversion coatings were investigated by scanning electron microscopy and X-ray diffraction. The results show that the cerium conversion coating can significantly delay the appearance of white rust on the hot-dip zinc coating. With the extension of the deposition time, the corrosion resistance of the conversion coating first increases and then decreases. When the deposition time is 30-60 min, The best corrosion resistance of the film. The cerium conversion coating is mainly composed of amorphous ZnO and CeO 2, which is not easy to form corrosion microcells in the corrosive medium.