High temperature oxidation of chromium: Kinetic modeling and microstructural investigation

• Detailed experimental analysis of oxidation of nominally pure chromium
• Theoretical model for diffusion of chromium and oxygen through the oxide
• Optimization of kinetic parameters using the CALPHAD method
• Validation of the diffusion model by doing oxidation simulations using DICTRA

Using CALPHAD methods, Cr2O3 growth on pure Cr is modeled using DICTRA and the vacancy model for diffusion. The results are compared with thermobalance and TEM experiments at 625 and 700 °C in O2. The experimental scatter is significant, leading to a compromise suggestion. With the experimental conditions from the furnace exposures in this work, optimized mobilities are validated with a series of oxidation simulations. Despite the complex microstructure and initial growth rate variations, it is possible to reproduce the experimental oxide thicknesses with good accuracy, allowing for extension to multicomponent systems.