Analytical model of selective external oxidation of Fe-Mn binary alloys during isothermal annealing treatment

[Display omitted] •An analytical model was developed to describe the kinetics of external selective oxidation of binary Fe-Mn alloys.•The model predicts the heterogeneous nucleation and growth of MnO oxides on the Fe-Mn surface.•The model calculates the size of the oxides and the surface area fraction covered by them.•The model results were validated by measurements conducted on annealed Fe-Mn alloys.•The model can be applied to continuous industrial annealing of steels. An analytical model was developed to describe the kinetics of external selective oxidation of Fe-Mn alloys during isothermal industrial annealing. This model describes the surface reactions and thermodynamics involving water vapor, the pre-oxidation and diffusion of oxygen and manganese and the heterogeneous nucleation and growth of MnO oxides on the surface. Theoretical equations were established and solved to calculate the critical radius and nucleation rate of MnO embryos, the size and surface coverage fraction of MnO oxides and the manganese concentration profiles as a function of annealing time. The model results were validated by annealing experiments at 800 °C.