镁合金铈转化膜在NaCl溶液中的腐蚀行为及腐蚀机理

摘要

通过静态浸泡腐蚀实验，采用扫描电子显微镜、X射线能谱仪、电化学实验等研究镁合金铈转化膜在0.05 mol/L NaCl溶液中的腐蚀行为，探讨膜层腐蚀机理。结果表明：随着浸泡时间的延长，膜层发生腐蚀和遭到破坏的程度也随之增强，浸泡初级腐蚀产物组织疏松，腐蚀后期腐蚀产物的致密性和紧实度增加；腐蚀产物主要由镁、氧等元素组成。随浸泡时间的延长，膜层电阻和腐蚀电位先增大后减小，腐蚀电流密度呈现先减小后增大的趋势。%The corrosion behavior and corrosion mechanism of the cerium conversion coating on magnesium alloy in 0.05 mol/L NaCl solution were investigated by using static immersing corrosion test, scanning electron microscope, energy dispersive spectrometer and electrochemical methods. The results show that with increasing the immersion time, the corrosion and damage degree of coating increase. The initial corrosion product is loose and the density and compactness of the coating corrosion products of coating increase, the main compositions of corrosion product, are Mg and O elements. The film resistance and corrosion potential increase at the first stage, and then decrease with increasing the immersion time, while the corrosion current density changes in the opposite tendency.