The crystallographic orientation dependent anisotropic corrosion behavior of aluminum in 3.5 wt% NaCl solution

Abstract

In this paper, a quantitative method to evaluate the degree of differences in corrosive behavior of different crystallographic-oriented planes of Al and Al alloys in 3.5 wt% NaCl solution is provided. The corrosion potential Ucorr, corrosion current density Icorr and electrochemical corrosion rate of (100), (110) and (111) ideal surfaces and corresponding surfaces with vacancy and chloride ion adsorption considerations in single-crystal aluminum were derived by first principles calculation. The results show that the corrosion potential and corrosive current density increases in the order of U(110)corr<U(100)corr<U(111)corr and I(111)corr<I(100)corr<I(110)corr, respectively, and the electrochemical corrosion rate of (111) surface is 0.01×10-3 mm/a, showing the superior corrosion resistance. Moreover, the effect of the addition of alloying elements on the corrosion behavior of M−alloying Al alloy matrix in comparison with pure Al was further investigated by first principles calculation, and elements of Li, Mg, Zn, Ag and Cd are selected to improve the corrosion resistance of Al alloy.