The Influence of magnesium alloy surface roughness on Ce salt conversion film corrosion resistance

Abstract

Cerium salt conversion films on magnesium alloys with different surface roughness were investigated by SEM, EIS and positron annihilation. The results showed that the conversion films prepared from more highly smoothed AM60B magnesium alloy substrates had larger impedance arc radius and smaller corrosion current. Positron lifetime measurement showed that as the smoothness of the substrate increased, the number of vacancy defects in the film layer or interface layer increased, corresponding to better coverage rate of the conversion film. It could be inferred that the corrosion resistance of the cerium salt conversion film on the magnesium alloy increases as the surface smoothness of the substrate increases.