Residual silicon in the reaction-bonded silicon carbide RBSiC can be replaced by refractory MoSi 2 by using Si-Mo alloy as infiltrants instead of pure Si. Transmission electron microscopy of these materials clarified the following results. The MoSi 2 existed in the SiC grain boundaries and many fine grains of SiC were found in the MoSi 2 phase. The carbon particles were thought to be dissolved into the Si melt including Mo and reprecipitated as SiC particles in the solution-reprecipitation

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... nism. The Mo concentration in the Si-Mo melt increased with the reprecipitation of SiC particles, and the MoSi 2 was precipitated in the grain boundaries. The presence of the fine SiC particles in the MoSi 2 phase suggests that the carbon have a fairly strong interaction with silicon in the melt and diffuse not as isolated atoms, but as C-Si pairs.