Improving the High-Temperature Oxidation Resistance of Cast WE43 Magnesium Alloy by Adding Ca Element

Oxidation resistance, surface morphology and combustion products of WE43-xCa ( x = 0, 1, 1.5, and 2 wt.%) alloys were investigated at 500 °C, 550 °C, and 600 °C. Results indicated that the weight gain of the WE43 alloy at various temperatures followed a parabolic pattern over time. At high temperatures, the oxidation resistance of WE43 alloy with Ca element was superior to that of 0Ca alloy. After high-temperature oxidation, a loose oxide film with longitudinal cracks was created. Near the surface, internal oxide connections formed, and oxygen elements diffused throughout the matrix. The addition of Ca resulted in the generation of Y 2 O 3 and CaO, which were considered to be the protective oxide film, and the dense mixed oxide layer delayed the inward diffusion of oxygen ions O 2− , thus improving the oxidation resistance of the alloy at high temperatures.