采用原位椭圆偏振光谱法研究镁合金在模拟工业冷却水中的腐蚀及添加钼酸钠对腐蚀的抑制作用,利用单层膜模型解析椭圆偏振光谱实验数据,得到“电极-介质”界面层厚度及光学常数的动态变化规律,由此将镁合金在模拟冷却水中的腐蚀分为3个阶段:自然氧化膜溶解、吸附膜形成、腐蚀产物沉积,添加钼酸钠使腐蚀过程中自然氧化膜溶解减弱、吸附膜和沉积膜变得致密,从而有效抑制镁合金腐蚀.
In situ spectroscopic ellipsometry was employed to investigate the corrosion behavior of AZ40 magnesium alloy in a simulated cooling water without and with molybdate inhibitor. By deeonvoluting the ellipsometric data with a one-layer model, the evolution of the refractive indices and the thickness of the interface layer of “electrode-medium” were obtained. Based on the deconvolution results,three regimes, which were dissolution of native oxide film, formation of adsorption film and precipitation of corrosion products, were proposed for the corrosion process of magnesium alloys in the simulated cooling water. The addition of molybdate weakened the dissolution of the native oxide film and made the adsorption film and the precipitated film much compact,which was responsible for the effective inhibition of molybdate on corrosion of magnesium alloys in the simulated cooling water.