Irradiation accelerated corrosion of alumina-forming austenitic steels in supercritical CO2: The oxide scale formed within an individual grain or affected by grain boundary

Abstract

The irradiation accelerated corrosion within monolayer grains of a new AFA steel exposed to sCO2 are studied. The presence of irradiation induced dislocation loops accelerate element diffusion and reduces corrosion resistance by ∼44%. Many oxide scale features are firstly found, including a two-phase inner layer consisting of Ni-rich austenite and Cr-rich spinel, and Al2O3/SiO2 oxide precipitates. Irradiation leads to an additional Cr-rich oxide layer at the bottom of inner layer and a narrower Al2O3 band in the internal oxidation layer. Irradiation also induces Cr depletion at grain boundaries, thereby impeding the formation of a protective Cr-rich oxide scale.