Owing to the development of high temperature applications using SiC, this study examines the effect of TiN coatings against Si and C atoms diffusion in presence of two refractory metals (W or Mo). Indeed, SiC reacts rapidly with these metals at elevated temperatures generating unacceptable reaction zones and a mechanical embrittlement. Samples used during this work were prepared on wire and planar metallic substrates, SiC and TiN being deposited by CVD. The effect given by TiN interlayers with thicknesses between 10 and 20 mu m was considered at 1773 K. From our results, TiN can be considered as an effective diffusion barrier in presence of W, whereas it ensures no real protection in the case of Mo-containing samples.