Fabrication of MoSi2 coatings on molybdenum and its high-temperature anti-oxidation properties

Industrial spent MoSi2-based materials were used to fabricate oxidation-resistant coatings on molybdenum via slurry painting in air. The microstructure, phase constituent and high-temperature oxidation behaviors of the coatings at 1500 °C were explored. The results show that the bonding layer is generated in the coatings after sintering, which strengthens the metallurgical combination between the coating and the substrate because of the formation of diffusion layers. Rare cracks appear in the coating using pure MoSi2 (PM coating) while the coating using spent MoSi2 (SM coating) is free of cracks due to decreased thermal expansion mismatch. After oxidation, the oxide scale of PM coating possesses large-sized pores while a relatively dense oxide scale is acquired by SM coating. Compared with PM coating, thinner glassy oxide scale with lower mass gain is obtained by SM coating, exhibiting better anti-oxidation properties at 1500 °C.