Surface Reactivity of Magnesium Alloys in Solid and Liquid States

Abstract

The major factors, controlling surface degradation of magnesium alloys in oxygen‑containing atmospheres at temperatures of solid and liquid states, are reviewed. While thin oxide films, formed during initial stages, exhibit some protective behaviour, thick scales grown at high temperatures do not block the outward diffusion of metal ions, leading to non-protective oxidation. The high vapour pressure of magnesium increases surface degradation and reduces effectiveness of inert atmospheres. Thus, both the solid and liquid states rely on the formation of compact oxide layers on the metallic surface, suppressing evaporation and oxidation. The role of protective atmospheres and alloy chemistry in reducing surface reactivity is discussed.