Microstructural evaluation of oxide layers formed on Fe-22Cr-6Al metallic foam by pre-oxidization

Three types of oxide layers Al2O3, Al1.98Cr0.02O3, and AlFeO3 phases on the surface of Fe-22Cr-6Al (FeCrAl) foam during pre-oxidation were characterized by means of transmission electron microscopy (TEM). The growth rate of each oxide layer was investigated using measurement of total weight gain. The Al2O3 layer mainly affected the growth rate of the total oxide layer, and it hindered the diffusion of Fe and Cr atoms from the matrix to the oxide layers.