Microstructure and high-temperature oxidation behavior of Ti₃SiC₂/MoSi₂ composite coatings prepared by spark plasma sintering

In this study, Ti₃SiC₂/MoSi₂ composite coatings were fabricated on Nb-Si-based alloys by spark plasma sintering (SPS) technique using Ti₃SiC₂, Mo, and Si powder mixtures. The effect of Ti₃SiC₂ powder content on the microstructure and high-temperature isothermal oxidation resistance of these composite coatings was investigated. By increasing Ti₃SiC₂ powders content from 10 to 50 and 70 vol.%, the volume fractions of Ti₃SiC₂ and TiC in composite coatings are 7.45, 34.99, and 52.12 vol.%, respectively. The 10% Ti₃SiC₂/MoSi₂ composite coatings can protect Nb-Si-based alloys from isothermal oxidation at 1250 °C for 200 h, while adding excessive Ti₃SiC₂ powders in the coating will induce severe cracking of the scale due to an increase in the brittle TiC phase.