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 degrees C and 2100 degrees 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 degrees 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 degrees 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 5N and 10N loads, respectively. SiC-TiB2 and SiC-TiB2-TaC composites show constant thermal conductivity response above 810 degrees C and 603 degrees C in the. range, of 48.70-47.15 W/m K and 60.35-60.41 W/m K, respectively.