Formation Mechanism of Oxide Scales Grown on X10CrAlSi18 and 310S Heat-Resistant Stainless Steels Under High Temperature in Air

To promote the application of resource-saving heat-resistant stainless steels, the study on high temperature oxidation behavior and oxide-scales formation mechanism of X10CrAlSi18 ferritic heat-resistant stainless steels (FHSSs) and 310S austenitic heat-resistant stainless steels (AHSSs) was carried out in air up to 140 h, and the microstructure of oxide scales, oxidation kinetics and thermodynamics theories, and the classical hypothesis of the third-element effect analyzed. The results showed that the cost-effective X10CrAlSi18 FHSSs presented good oxidation resistance at 800 and 900 degrees C due to the compact multicomponent oxide scales composed of Al2O3, Cr2O3, MnCr2O4 and MnFe2O4 and good adhesion to the matrix. However, the oxidation resistance of the alloy at 1000 degrees C was deteriorated, which is mainly due to the non-protective Fe2O3. The oxide scales of 310S AHSSs containing Cr2O3, MnCr2O4 and inner SiO2 exhibited good oxidation resistance, while the internal oxidation of silicon weakened the adhesion to the substrate.