Oxidation Resistance of Mg-Ca Alloys with Protective Coating Under Flame Exposure

Abstract:

To further expand the application of Mg alloys at high temperatures, the oxidation resistance of Mg-0.3Ca and Mg-3.6Ca alloys with protective coating under flame exposure was studied. Results show that the oxidation resistance of Mg-Ca alloys under flame exposure is significantly improved by the protective coating, and Mg-3.6Ca alloy shows better oxidation resistance performance. The surface temperature of Mg-Ca alloys is reduced by the coating, therefore improving the oxidation resistance under flame exposure. However, the thermal insulation effect of the coating on Mg-3.6Ca alloy is better, which can be attributed to the Ca accumulation on the surface film. In addition, the surface film with Ca accumulation layer plays a crucial role in protecting the alloy. No obvious Ca accumulation layer exists on the Mg-0.3Ca alloy surface, presenting a restricted protective effect. Nevertheless, the surface film containing Ca accumulation layer is formed on Mg-3.6 Ca alloy, which shows an excellent protective effect.