Oxidation and interdiffusion behavior of Mo-Si-B coating on Nb-Si based alloy prepared by spark plasma sintering

Abstract Mo-62Si-5B coating was prepared by spark plasma sintering (SPS) to protect Nb-Si based alloy from oxidation. Oxidation and interdiffusion behavior of Mo-62Si-5B coating on Nb-Si based alloy was investigated in air over the temperature range of 1200–1300 °C. With the oxidation temperature increasing, the oxidation rate constant of the specimen increases. The activation energy for oxidation is calculated as 124 ± 9 kJ/mol. Growth of the interdiffusion zone obeys the parabolic law. The activation energy for the growth of the interdiffusion zone is 187 ± 2 kJ/mol. The interdiffusion coefficients of Si in the interdiffusion zone at 1200 °C, 1250 °C and 1300 °C are calculated.