Fabrication and properties of ZrC–ZrB₂–SiC composites by spark plasma sintering

Ternary composites of ZrC–ZrB2–SiC were successfully synthesized via spark plasma sintering at 1600, 1700 and 1800°C for 5 min under a pressure of 40 MPa with ZrB2, ZrC and SiC powder as the raw materials, respectively. The microstructures, phase composition and mechanical properties were studied by scanning electron microscopy, X-ray diffraction and three-point bending test, respectively. The relative density, apparent porosity and flexural strength of the ZrC–ZrB2–SiC composite were 93.1%, 0.89% and 383.15 ± 13.56 MPa at 1800°C, which showed the preferable mechanical property and denser microstructure than these properties of 88.0%, 1.68%, 369.77 ± 12.73 MPa at 1600°C and 90.1%, 1.20%, 379.71 ± 12.44 MPa at 1700°C. The comparison showed 1800°C was the best sintering temperature that the ternary composites owned the best microstructures, phase composition and mechanical properties in this experiment.