Oxidation Properties of Fe‐Al Alloys (1.5–5 a/o Al) in Oxygen at 1173 K

Abstract

Oxidation properties of Fe‐1.5, 3, and 5 atomic percent (a/o) Al alloys were investigated at 1173 K in oxygen at 1 bar pressure. The reaction kinetics were represented by two limiting parabolic stages, a rapid initial stage and slow final stage separated by a transient period. The initial oxidation rate was more rapid with increasing alloy aluminum content. The reaction products of the 1.5 and 3 a/o Al alloys formed a duplex scale consisting of an outer and an inner layers with platelet precipitates which extended across the internal oxidation zone in the alloys. In the case of the Fe‐5 a/o Al alloy, a triplex scale ultimately developed as the internal oxidation zone was completely converted to oxide upon growth of an film at the internal oxidation front.