Nucleation-induced kinetic hindrance to the oxide formation during the initial oxidation of metals

A kinetic model is developed to elucidate the nucleation rate of oxide islands during the initial stages of oxidation of metals. Our theoretical analysis shows that the nucleation of oxide islands requires a critical oxygen pressure below which the nucleation rate is practically equal to zero and increases dramatically beyond it. The kinetic model shows that this critical oxygen pressure is many orders of magnitude larger than the equilibrium oxygen pressure predicted from the bulk thermodynamics. Comparison between the kinetic model and experimental data is made over a wide range of oxidation temperature.