Dense SiCf/MoSi2 composite via liquid silicon infiltration

Silicon carbide fiber reinforced MoSi2 matrix composite (SiCf/MoSi2) is prepared by liquid silicon infiltration at 1450°C. SiC fiber preform is first impregnated with phosphomolybdic acid (PMA) solution in ethyl alcohol. After calcinations, the PMA is converted into MoO3. Following the heating in hydrogen atmosphere, the MoO3 is reduced into metallic Mo, leading to a porous SiCf/Mo. The porous preform is then infiltrated with liquid silicon above silicon melting point to produce SiCf/MoSi2. The microstructure evolution and the underlying mechanism are studied. It is found that MoSi2 is formed by dissolution‐precipitation. Through multiple impregnation‐calcination cycles, a fully dense SiCf/MoSi2 can be obtained with MoSi2 as the continuous matrix phase. The presence of Mo is found to significantly reduce the attack of liquid silicon the silicon carbide fiber reinforcements.