SiC-Si composites are widely used either as a bulk material or as a matrix for fiber reinforced ceramics. In the current research, nanocomposites of SiC-Si with different volume fractions of Si were sintered by spark plasma sintering -SPS- for first time. The effect of Si content and different sintering parameters on relative density, microstructure, hardness and fracture toughness of the sintered materials have been investigated. The relative density increased from about 83% to 99% by increasing the sintering temperature to 1700 °C, sintering time to 10 min, and pressure to 70 MPa for composites containing >20 vol.% Si. The results revealed that the full dense SiC-20 vol.%Si composite can be obtained by spark plasma sintering at 1700 °C, 10 min and 70 MPa. Moreover, in this condition, the hardness and toughness of the composites reached the optimum values.

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