First-principles modeling of the anodic and cathodic polarization to predict the corrosion behavior of Mg and its alloys

Theoretical models predicting the corrosion behavior of magnesium (Mg) alloys often require some empirical parameters that are obtained from experiments. Here, we develop a first-principles-based electrochemical model to simulate the anodic and cathodic polarization curves of Mg and its alloys in the aqueous solution. Consistent with experimental observations, our model successfully predicts the anisotropic corrosion resistance of different crystallographic planes in Mg. Moreover, analysis of the anodic dissolution process shows that some alloying elements, such as Cr, Cd, Pt, Au, Hg, Ga, Ge, As, In, and Tl, when present in solid-solution state, could effectively improve the corrosion resistance of Mg matrix. Our model, which does not require any experimental parameters as an input, could be a useful tool for screening better corrosion-resistant Mg alloys.