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

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 degrees 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 degrees C, 1250 degrees C and 1300 degrees C are calculated.