用热重法测定镁熔体在HFC-32(二氟甲烷)/CO2气氛中的氧化动力学曲线,用XPS和XRD表征表面氧化膜中氧化产物的组成,讨论镁熔体在HFC-32/C02气氛中的氧化机理。结果表明:镁熔体在HFC-32/C02气氛中的氧化行为遵循抛物线规律,氧化膜的组成与HFC-32的浓度和温度有关;随着HFC-32浓度的增大,氧化膜中MgO的含量减小,MgF2的含量增大,氧化速率减小;随着温度的升高,氧化膜中MgO的含量增大,MgF2的含量减小,氧化速率增大。
The oxidation kinetic curves of molten magnesium in atmospheres of HFC-32 (methylene fluoride)/CO2 were measured by the weight gain method. The oxidation products contents of oxidation surface film were characterized by XPS and XRD. The oxidation mechanism of the magnesium in the mixed gas of HFC-32/CO2 was discussed. The results show that the oxidation behavior follows parabolic law and the film compositions change with the concentration of HFC-32 and the oxidation temperature. With the increase of the HFC-32 concentration in the mixed gas, the content of MgO in the oxide film decreases, the content of MgF2 increases, and the oxidation rate decreases. As the temperature increases, the content of MgO in the oxide film increases, the content of MgF2 decreases, and the oxidation rate increases.