Oxidation behavior of ignition-proof magnesium alloys with rare earth addition

Ignition-proof magnesium alloy is obtained in Mg-Y-Ce system, which can be melted at 1173K in air without any protections. A dense and compact oxide film is obtained on the surface of molten Mg-Y alloys when the concentration of Y is greater than 10 wt%. With the addition of Ce the critical concentration of Y in Mg-Y alloys for forming a protective film is decreased significantly from 10 wt% to 3 wt%. AES and XRD analysis reveal that the oxide film formed on the surface of Mg-3Y-4.5Ce alloy is mainly composed of Y(2)O(3) and Ce(0.202)Y(0.798)O(1.601). Based on the theoretic analysis and experimental results, a selective oxidation model of Mg-Y alloys at high temperatures is developed, and the third-element effects of Ce in Mg-Y alloys are discussed in detail. (C) 2010 Elsevier B.V. All rights reserved.