对镁合金ZK60和ME20熔体与镁熔体在1％HFC-134a/空气气氛中的高温氧化行为进行比较.使用热重仪测定这3种熔体的氧化动力学曲线,使用扫描电镜观察氧化后样品表面的形貌,并用X射线衍射仪和X射线光电子能谱仪分析样品表面的相成分.结果表明:ZK60和ME20镁合金熔体在1％ HFC-134a/空气气氛中的氧化速度远远低于镁熔体的氧化速度;镁熔体表面所形成的氧化膜主要由MgF2、MgO和C组成,而ZK60和ME20镁合金熔体表面所形成的氧化膜除了含有MgF2、MgO和C以外,还分别含有少量的ZrF4和CeF4.ZK60和ME20镁合金熔体在该气氛中氧化阻力的提高分别与它们的合金元素Zr和Ce有关.%The oxidation behaviour of molten ZK60 and ME20 magnesium alloys in 1％ 1,1,1,2-tetrafluoroethane/air atmospheres at 720 ℃ was compared with that of molten magnesium.The oxidation kinetics of these three melts was determined by thermograyimetric measuring instmmem,and the surface films of the oxidized samples were examined by scanning electron microscope(SEM),X-ray diffractometry(XRD)and X-ray photoelectron spectroscopy(XPS).The results show that the oxidation rate of molten ZK60 or ME20 alloys is much lower than that of molten magnesium in 1％ 1,1,1,2-tetrafluoroethane/air atmospheres.The surface film formed on the molten magnesium is composed of MgF2,MgO and C,while the film formed on ZK60 melt mainly consists of MgF2,MgO,C and some ZrF4,and the film on ME20 mainly consists ofMgF2,MgO,C and a small amount of CeF4.The good oxidation resistances of ZK60 and ME20 alloy melts may be caused by their major alloying elements Zr and Ce,respectively.
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