Preparation and 1500 °C oxidation behavior of crack-free bentonite doped MoSi2 protective coating on molybdenum

Spark Plasma Sintering technique was applied to fabricate MoSi 2 and MoSi 2 -bentonite coatings on molybdenum. The phase composition, morphologies and anti-oxidation properties of the coatings at 1500 °C were investigated. Penetrated cracks generated in MoSi 2 coating after SPS while the composite coating was crack-free because of the reduction of CTE mismatch. Cracks existed in the silica layer of MoSi 2 coating after oxidation while the silica layer of bentonite-containing coating showed dense and crack-free morphologies. Compared with MoSi 2 , the composite coating possessed thinner Mo 5 Si 3 diffusion layer and silica layer, exhibiting less loss of substrate and coating with improved oxidation resistance.