In-vitro corrosion behaviors of extruded Mg–Ga alloys in alpha minimum essential medium

Abstract

The in-vitro corrosion behaviors of extruded Mg–xGa (x = 1, 3, 5) alloys in alpha minimum essential medium (α-MEM) were investigated. The bilayer corrosion film was composed of an outer layer dominated by amorphous phosphates–carbonates and an inner layer dominated by MgO–Mg(OH)2. Pure Mg and Mg–1Ga exhibited low corrosion rates and homogeneous corrosion behaviors owing to the protection from the compact corrosion films. By contrast, Mg–3Ga and Mg–5Ga exhibited high corrosion rates and inhomogeneous corrosion behaviors owing to the bulky micro-galvanic corrosion caused by Mg5Ga2. Based on these results, possible corrosion models were developed.