Behavior of surface oxidation on molten Mg-9Al-0.5Zn-0.3Be alloy

Excellent ignition proof performance was obtained during the melting of Mg- 9Al-0.5Zn-0.3Be alloy directly in the atmosphere. XRD and AES analysis indi cated that the oxide film on the surface of the molten Mg 9Al-0.5Zn-0.3Be a hoy exhibited a duplex structure, which was in agreement with the result of thermodynamic analysis. The outer layer of the oxide film mainly consists of MgO. which grows according to the parabolic law. The inner layer is a mi xture of MgO and BeO, and its growth follows a linear law approximately. Th is inner layer acts as a barrier to reduce the outward diffusion of Mg2+, w hich leads to the excellent ignition proof performance. An oxide model was established to describe the oxidation procedure on the surface of the molte n Mg-9Al-0.5Zn-0.3Be alloy. (C) 2001 Elsevier Science B.V. All rights reser ved.