AZ91镁合金熔体在HFC-134a /空气气氛中的高温氧化特性
High Temperature Oxidation Characteristics of Molten AZ91 Alloy in Atmosphere Containing HFC-134a
陈虎魁
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作者单位：宝鸡文理学院 化学化工系， 陕西 宝鸡 721013
中文关键字：AZ91镁合金； 熔体； 氧化； HFC-134a
英文关键字：AZ91 alloy; melt; oxidation; HFC-134a
中文摘要：对AZ91镁合金熔体在HFC-134a(1，1，1，2-四氟乙烷) /空气气氛中的氧化特性进行了研究。用热重法测定了氧化动力学曲线，用扫描电镜分析了氧化膜形貌，用X-射线衍射仪和X-射线光电子能谱仪分析了氧化膜中氧化产物的组成。结果表明：AZ91镁合金熔体在HFC-134a/空气气氛中的氧化行为主要与HFC-134a的浓度有关。当HFC-134a浓度较高时，氧化表现出抛物线(或直线与抛物线的组合)特征，氧化膜具有保护性，主要由MgF2、MgO、C和少量的AlF3组成；当HFC-134a浓度较低时，氧化表现出线性(或抛物线与直线的组合)特征，氧化膜不具保护性，主要由MgO、Mg3N2和少量AlN组成。另外，熔体温度对该合金的氧化也有影响。
英文摘要：Molten AZ91 alloy was oxidized in atmosphere containing HFC-134a at 660 ℃ and 720 ℃. The oxidation kinetic curves were measured by weight gain. The surface morphologies and oxidation products were characterized by SEM, XRD and XPS. The results show that the oxidation kinetics of molten magnesium are greatly influenced by the concentration of HFC-134a. When the concentration of HFC-134a in air is high, the oxidation of molten AZ91 magnesium alloy follows parabolic rate law and the film mainly consists of MgF2, MgO, C and small amounts of AlF3, which has protective. When the concentration of HFC-134a in air is low, the curve of oxidation weight gain against time is linear and the oxidation film mainly consists of MgO, Mg3N2 and small amounts of AlN, which has no protective. The temperature has great effects on the oxidation of molten AZ91 alloy.