Oxidation behavior of Si- rich Mo-Si-B coating doped with La by spark plasma sintering

Abstract In this study, Mo-60Si-5B coating doped with 0.5 at% La was deposited on Nb-Si based alloy by spark plasma sintering and the oxidation resistance of the coating at 1300 ℃ was investigated. The results show that the mass gains of 0.5La-Mo-60Si-5B and Mo-60Si-5B coatings are 0.85 mg/cm−2 and 1.02 mg/cm−2 after oxidation at 1300 ℃ for 100 h, respectively. Good oxidation resistance of the coating is attributed to the formation of the glass phases La2SiO5 and SiO2 with low oxygen permeability, as well as the inhibition of oxygen diffusion due to the segregation of La2O3 at the grain boundary.