Effects and mechanisms of rare earth and calcium on the flame retardancy of magnesium alloys

This paper focuses on the effects and mechanisms of rare earth and calcium on the flame retardancy of magnesium alloys. Rare earth elements form dense composite oxide films on the surface of the melt, effectively inhibiting the progress of oxidation reactions and significantly increasing the ignition temperature of magnesium alloys. The mechanisms and optimal compositional ranges of different rare earth elements on the flame retardancy of magnesium alloys. Calcium form CaO-rich oxide films in magnesium alloys, which can effectively prevent oxygen diffusion and enhance the flame-retardant resistance of the alloy. When rare earth elements are compounded with calcium, a notable flame-retardant effect is observed. Composite application can maximize the flame-retardant effect of alloy elements while balancing the influence on various properties. Additionally, the authors illustrate through their own research that precise compositional optimization design is required to efficiently exploit the synergistic effects of RE and Ca and mitigate their adverse impacts.