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

Abstract

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.