Mechanical and Tribological Properties of Spark Plasma Sintered SiC–TiB₂ and SiC–TiB₂–TaC Composites: Effects of Sintering Temperatures (2000 °C and 2100 °C)

SiC–TiB₂ (10 wt. %) and SiC–TiB₂ (10 wt. %)–TaC (5 wt. %) composites are consolidated using spark plasma sintering (SPS) technique at different sintering temperatures (2000 °C and 2100 °C) for 15 min soaking time under 35 MPa pressure. The effects of sintering temperature on densification and mechanical properties of composites have been investigated in detail. SiC–TiB₂ and SiC–TiB₂–TaC composites sintered at 2100 °C showed high Vickers hardness value, i.e., 27.20 ± 1.23 GPa and 26.40 ± 0.80 GPa, respectively, under 1 kgf (9.81 N) load. Poor fracture toughness {2.28 MPa(m)^1/2 at 1 kgf (9.81 N) load} of monolithic silicon carbide (SiC) sintered at 2100 °C is improved with addition of titanium diboride (TiB₂) and tantalum carbide (TaC) as secondary phases. Scratch resistance of SiC–TiB₂ and SiC–TiB₂–TaC composites show coefficient of friction value below 0.40 and 0.50 under 5 N and 10 N loads, respectively. SiC–TiB₂ and SiC–TiB₂–TaC composites show constant thermal conductivity response above 810 °C and 603 °C in the range of 48.70–47.15 W/m K and 60.35–60.41 W/m K, respectively.