不同电流密度对锌表面含铈氧化膜耐蚀性的影响

Influence of Different Current Density on Corrosion Resistance of Cerium-containing Oxide Film on Zinc Surface

采用电化学阳极氧化方法在锌表面制备了氧化膜,并研究了氧化膜的表面形貌、元素组成和耐蚀性。采用场发射扫描电子显微镜(SEM)和能谱仪(EDS)研究制得的氧化膜表面形貌及元素组成;采用X射线光电子能谱仪(XPS)分析氧化膜表面元素价态;通过Tafel曲线和交流阻抗谱(EIS)研究氧化膜的耐蚀性并探讨其耐蚀机理。结果表明:氧化膜中主要成分为ZnO和CeO2;电流密度能够影响氧化膜的表面形貌和元素组成,进而影响到氧化膜的耐蚀性。在一定范围内,膜层中铈含量随电流密度的增加而增加,当电流密度为12mA/cm2时,膜层中铈含量达到最高,耐蚀性最好;锌表面含铈氧化膜主要抑制了锌腐蚀的阴极过程。

A composite oxide film has been fabricated on zinc surface by electrochemical oxidation method. The elementary composition, surface morphology and corrosion resistance of the film were investigated. The scanning electron microscope （SEM） and energy dispersive spectrometer （EDS） were used to analyze the surface morphology and elementary composition of the film. The X-ray photoelectron spectrometer （XPS） was used to alaalyze element valence state. Corrosion resistance was analyzed through polarization curves and electrochemical impedance spectroscopy （EIS）. The results showed that the main compositions in the surface oxide film were ZnO and CeO2. The current den sity could influence the surface appearance, elementary composition and corrosion resistance. Compared with other current densities, the film fabricated at 12 mA/cm2 has optimal corrosion resistance. Meanwhile it has the highest content of cerium. It is suggested the existence of the film could inhibit the cathodic process of zinc corrosion.