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用热重分析法测定了氧化动力学曲线,并采用XRD和SEM(EDAX)等手段,研究了Ni12.59Cr6.74Ta4.04A15.16Co1.35Mo6.29W合金在900℃和1000℃的高温氧化行为。结果表明,在氧化初期合金的氧化质量增加较快,随着氧化时间的延长质量增加的速率逐渐降低,其氧化动力学曲线符合抛物线规律。在900℃和1000℃氧化形成的氧化膜由三层组成,外层为Cr_2O_3,Al_2O_3,(Ni,Co)Cr_2O_4和CrTaO_4;中间层为平直的Al_2O_3层;内氧化层为Al_2O_3。在合金的氧化期间,分布在中间层的富Ta相可抑制基体中Al向外扩散,并抑制氧化膜的生长,使氧化速度降低。
The oxidation kinetics curves were determined by thermogravimetric analysis. The oxidation behavior of Ni12.59Cr6.74Ta4.04A15.16Co1.35Mo6.29W alloy at 900 ℃ and 1000 ℃ was studied by means of XRD and SEM (EDAX). The results showed that the oxidation mass of the alloy increased rapidly at the initial stage of oxidation, and the rate of mass increase gradually decreased with the increase of the oxidation time. The oxidation kinetics curve of the alloy accorded with the parabolic law. The oxide film formed by oxidation at 900 ℃ and 1000 ℃ consists of three layers, the outer layer is Cr_2O_3, Al_2O_3, (Ni, Co) Cr_2O_4 and CrTaO_4; the middle layer is a straight Al_2O_3 layer; the inner oxide layer is Al_2O_3. During the oxidation of the alloy, the Ta-rich phase distributed in the intermediate layer suppresses the outward diffusion of Al in the matrix and suppresses the growth of the oxide film to lower the oxidation rate.