Surface Fluorination of Magnesium Powder: Enhancing High-Temperature Oxidation Resistance

This study investigates the high-temperature oxidation mechanism of pure magnesium powder and the effect of surface fluorination on its oxidation resistance. The results showed that at high temperatures, pure Mg powder reacted with H₂O and CO₂ in air to form Mg(OH)₂ and MgCO₃, which decomposed at approximately 350 °C. Above 450 °C, the oxide film ruptured and catastrophic oxidation occurred. Surface fluorination with F₂ gas generated a dense, uniform MgF₂ protective film on the magnesium surface, significantly improving the ignition point and high-temperature oxidation resistance of Mg. Increasing the fluorination temperature increased the thickness and stability of the MgF₂ layer, thereby further enhancing oxidation resistance. In particular, samples fluorinated at 200 °C showed oxidation growth limited to approximately 3%, even after heating at 500 °C for 8 h in air. Adjusting the surface fluorination conditions can create a protective MgF₂ film to address high-temperature oxidation issues in magnesium powder metallurgy applications.