Effect of TiAlN diffusion barrier at MoSi2-SiO2 composite coating/Mo alloy interface

In order to reduce the interdiffusion at interface of the silicide coating/Mo alloy and improve the service life of the coatings. MoSi2-SiO2 composite coatings with TiAlN diffusion barrier were prepared on Mo alloy by magnetron sputtering and followed by hot press sintering in the present study. Oxidation and interdiffusion behaviors of the samples were investigated at 1200 degrees C in static air. The results show that MoSi2-SiO2 composite coatings have excellent high temperature oxidation resistance, and the inward diffusion of Si is greatly inhibited with the addition of TiAlN diffusion barrier. After oxidation at 1200 degrees C for 100 h, the mass change of the MoSi2- SiO2 composite coatings is only -0.059 mg/cm2 to -0.022 mg/cm2, the thickness of the interdiffusion zone is just only 3.4 mu m that is one order of magnitude smaller than TiAlN-free coating. The TiAlN diffusion barrier can effectively inhibit the interdiffusion of elements between the MoSi2-SiO2 composite coatings and the Mo alloy substrates.