CrO2(OH)2 volatilization rate and oxidation behaviour prediction of the NiCr coating in Air-H2O environment at 650 ℃

Abstract The volatilization rate and lifetime prediction of the NiCr coatings produced by high-velocity oxygen-fuel were investigated at 650 °C in air containing 20 % water vapour. Water vapour could significantly accelerate the consumption of Cr which reduced the service time of the coatings. Oxidation kinetic rate of the NiCr coating and volatilization rate of the CrO2(OH)2 were calculated using classical gas transport theory in the viscous-flow regime. According to the practical oxidation kinetic rate, we built a relationship to predict the lifetime of the NiCr coating.