Oxidation behavior of Fe-Ni-Al alloy at 900°C

To improve the oxidation resistance of Fe-Ni alloy, 50Fe-40Ni-10Al alloy was prepared. The high temperature oxidation behavior in air atmosphere at 900°C was studied. The oxide film was characterized by XRD, SEM, and EDS. Experimental results show that the parabola rule is followed during oxidation with the parabola constant of 2.714 × 10^-2mg²/(cm⁴·h). After an initial stage of fast reaction, this alloy is able to develop a continuous layer of alumina at the base of the scale, which prevents the oxidation of aluminum and that of other components, thus reduces the oxidation rate greatly. Most of the oxides are Fe₂O₃ and Fe₃O₄, small amount of those are Al₂O₃ and AlFe₂O₄ spinel. The content of Al₂O₃ in oxidation scale goes up during oxidation, when Fe₂O₃ and Al₂O₃ form solid solution. The prepared alloy has excellent oxidation resistance to be suitable for inert anode material.