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研究了Fe-65Cu-15Ni-5Al和Fe-45Cu-15Ni-5Al两种四元合金在900℃的恒温和循环氧化行为。在恒温氧化条件下,Fe-65Cu-15Ni-5Al合金的氧化速率低于Fe-45Cu-15Ni-5Al合金的;Fe-65Cu-15Ni-5Al合金的氧化动力学前期符合抛物线规律,后期为线性规律,Fe-45Cu-15Ni-5Al合金的氧化动力学符合抛物线规律。然而,在循环氧化条件下,Fe-65Cu-15Ni-5Al合金的氧化速率却高于Fe-45Cu-15Ni-5Al合金的。两种合金在恒温及循环氧化条件下,最外层都形成了以CuO为主的厚氧化层,中间层由Fe、Ni和Al的氧化物以及它们之间形成的复合氧化物组成。除了Fe-65Cu-15Ni-5Al合金在恒温条件下不发生内氧化外,其余情况内层都有不连续的Al2O3层形成,Al_2O_3层内侧发生了Al的内氧化。由于在循环氧化条件下,内层的Al2O3层在应力作用下容易破裂,富铜的Fe-65Cu-15Ni-5Al合金腐蚀速率大大高于Fe-45Cu-15Ni-5Al合金的。但是在恒温氧化条件下,富铜的Fe-65Cu-15Ni-5Al合金α相中的Al含量已达到形成保护性外氧化膜所需的临界浓度,因而比Fe-45Cu-15Ni-5Al合金具有更好的抗高温氧化能力。
The thermostatic and cyclic oxidation behaviors of two quaternary alloys Fe-65Cu-15Ni-5Al and Fe-45Cu-15Ni-5Al at 900 ℃ were studied. The oxidation rate of Fe-65Cu-15Ni-5Al alloy was lower than that of Fe-45Cu-15Ni-5Al alloy at constant temperature. The oxidation kinetics of Fe-65Cu-15Ni-5Al alloy was in accordance with the parabolic law and linear with the latter , The oxidation kinetics of Fe-45Cu-15Ni-5Al alloy accord with the law of parabola. However, the oxidation rate of Fe-65Cu-15Ni-5Al alloy is higher than that of Fe-45Cu-15Ni-5Al alloy under cyclic oxidation conditions. Under both constant temperature and cyclic oxidation conditions, the two outermost layers formed a thick CuO-based oxide layer on the outermost layer. The middle layer consisted of the oxides of Fe, Ni and Al and the composite oxides formed between them. In addition to the internal oxidation of Fe-65Cu-15Ni-5Al alloy does not occur under the conditions of constant temperature, the rest of the inner layer has a discontinuous Al2O3 layer, Al 2 O 3 layer inside the internal oxidation occurred. The corrosion rate of the Cu-rich Fe-65Cu-15Ni-5Al alloy is much higher than that of the Fe-45Cu-15Ni-5Al alloy because the inner Al2O3 layer is easily ruptured under cyclic oxidation conditions. However, under the isothermal oxidation condition, the Al content in the α-phase of the copper-rich Fe-65Cu-15Ni-5Al alloy has reached the critical concentration required for the formation of a protective outer oxide film, and thus has more properties than the Fe-45Cu-15Ni-5Al alloy Good resistance to high temperature oxidation.