Effects of silicon additions on the oxide scale formation of an alumina-forming austenitic alloy

Abstract

This study investigated the effect of silicon additions on the oxidation behaviour of an alumina-forming austenitic (AFA) stainless steel at high temperatures in air with 10% water vapour. The AFA steels exhibited good oxidation resistance with less than 0.3wt.% Si due to the formation of a dense, continuous and protective Al2O3 scale. However, silicon additions of more than 0.3wt.% stimulated B2-NiAl precipitation and reduced the Al concentration in the austenite matrix, leading to its degradation with oxidation resistance at 800°C in air with 10% water vapour.