High temperature oxidation characteristics and mechanism of molten magnesium in the atmosphere of air containing HFC-134a

Molten magnesium has been oxidized in the atmospheres of air containing HFC-134a in the temperature range from 660°C to 800°C. The oxidation kinetic curves of molten magnesium have been measured by the weight gain method. The oxidation products have been characterized by XRD and EDS. The results show that the oxidation kinetics of molten magnesium are greatly influenced by the concentration of HFC-134a and temperature. The curve of oxidation weight gain against time is linear and the oxidation film consists mainly of MgO when the concentration of HFC-134a in air is low. The oxidation follows parabolic rate law and the film consists mainly of MgF₂ when the concentration of HFC-134a in air is high. An oxidation mechanism of molten magnesium in air containing HFC-134a has been proposed to account for the experimental results.