The development of Sic monofilament-reinforced titanium metal matrix composites is very important considering their good mechanical properties. Their potential applications in aerospace and aeronautics industries were the driving force to develop materials with high thermal stability. The mean disadvantage of these materials is a loss of strength due to interfacial reactions during consolidation, and subsequent thermal exposure in service. Some carbon [1 to 31], oxide [4 to 61], and titanium diboride [7] coatings on Sic fibres have been studied. However, they do not inhibit diffusion phenomena and do not exhibit good oxidation resistance. Within the framework of research aimed at protecting the fibres from the titanium matrix, other coatings on SIC filaments were designed, in order to ensure that each phase remains in thermochemical equilibrium. A study on SIC plane substrates was carried out to allow surface analysis by Rutherford backscattering spectroscopy (RBS) and Auger electron spectrometry (AES). The studied coatings were of titanium silicide, which is formed during SiC/Ti composite consolidation [8] and has a good oxidation resistance [9]. A previous study of TiSi, coatings on SIC filaments (SiC/TiSi2/Ti, [lo]) has shown that it is necessary to realize a double coating TiSi2/Ti,Si, in order to improve the thermochemical equilibrium.