The oxidation improvement of Fe3Al based alloy with cerium addition at temperature above 1000 °C

In the present paper, the oxidation behaviors of some Fe3Al alloys have been studied. Results indicate that the oxidation resistance of the binary Fe3Al decreases rapidly with the temperature increase above 1000 °C. Morphological observations of the oxide layers indicate that the poor oxidation resistance is mainly manifested by scale failure, especially cracking and severe spallation. Microalloying of cerium can improve the oxidation resistance of Fe3Al based alloy significantly. Compared with cerium-free alloys, the oxidation rate of cerium-containing alloys is reduced sharply, no cracks or signs of spallation exist on the surfaces of oxide scales, and the scales are smooth and flat during oxidation even at 1200 °C for 120 h. The morphological observations and microanalyses suggest that cerium has an effect on prevention of outward diffusion of cations through the short-circuit paths during oxidation, which prevents cavities forming near substrate–oxide interface, so that the alloy shows a dramatic improvement in scale adhesion. In addition, cerium addition can refine the oxide grains and reduce the iron or chromium oxides in the alumina scale, both of them are beneficial in improvement of strength for an alumina scale, and prevent the crack formation of scale.