Preparation of a dense MoSi₂ coating on Nb–Si based alloy with enhanced oxidation resistance via slurry sintering method

To overcome the critical issue of low density of the MoSi₂ coating prepared by slurry sintering method, a novel strategy of adding diffusion barrier (DB) at the interface was developed to achieve a high density of the coating. The effect of sintering process on the density and microstructure of the MoSi₂ coating was investigated systematically. The addition of DB promotes the formation of dense MoSi₂ coatings with a low area porosity of 0.96–3.98 %, while the value is basically over 41 % for the coatings without DB. The MoSi₂ coating with DB shows an enhanced oxidation resistance due to its dense structure as well as the reduction of the inward diffusion loss of Si by the DB during oxidation.