The oxidation behavior of Fe-20at.%Cr-10at.%Al alloys with a small amount of an
additional element such as W, Cu, Mn, Nb, Mo, Re, Co or Ti was investigated at 900 °C for up to
625hr. The fourth element addition to the FeCrAl alloy could be classified into two groups;
elements (Mn, Nb, Ti) that are contained in the Al2O3 scale, and elements (W, Mo, Re, Co) which
are not present in the scale. In the latter case, the elements (W, Cu) caused scale spallation. The
rumpling of alloys with Mn, Nb or Ti was smaller than that of the other alloys. The surface of the
alloy with Ti was the smooth. Pt marker experiments suggested that the Al2O3 scale formed on the
alloy with Ti grew by inward diffusion of O, whilst the Al2O3 scale formed on the FeCrAl alloy
grew by both outward diffusion of Al and inward diffusion of O. This different growth behavior due
to the elements incorporated in the Al2O3 scale could have an effect on the surface rumpling
behavior.
Metastable-stable phase transformation behavior of Al2O3 scale formed on Fe-Ni-Al alloys