Residual stresses in oxide scale formed on Fe-17Cr stainless steel

The purpose of this work was to investigate residual stresses in the oxide scale formed on ferritic stainless steel, which is proposed to be used as interconnector in the planar solid oxide fuel cells (SOFCs). The oxidation of the alloy has been conducted at 700 °C, 800 °C and 900 °C for 12-96 h by thermal gravimetric analysis (TGA) system. The oxide surface morphology, cross-section microstructure and the chemical composition of the oxide scale were studied after oxidation, and the residual stresses distribution of the oxide scale were determined at room temperature. It has been found that the oxide scale composed of an inner Cr2O3 layer and an outer Mn1.5Cr1.5O4 spinel layer, the residual stresses in both oxide layers are compressive and the growth stresses plays an important role. The competition of the stresses generation and relaxation during oxidation and cooling affects the residual stresses level. The evolution of residual stresses in the two layers is different according to the oxidation temperature, and the stresses in the two layers are interactional.