Tribological Properties of Si ₃ N ₄ / SiC Nano–Nano Composite Ceramics

Abstract

Fabrication of Si 2 N 2 O phase free, fully densified Si 3 N 4 / SiC nano–nano composite ceramics was done by combining a carbothermal reduction treatment ( CRT ) and a spark plasma sintering ( SPS ) using commercially available Si 3 N 4 and SiC nano‐powders, and their mechanical and tribological properties were investigated. CRT was conducted at 1450°C for 10 h with a phenolic resin and SPS was carried out at 1550°C for 5 min, which yielded the fully dense (>98% of theoretical density) Si 3 N 4 / SiC nano–nano ceramics with ~100 nm grain size. The elastic modulus, hardness, and fracture toughness increased with increasing SiC content up to 20 wt%. The wear rate of Si 3 N 4 / SiC nano–nano ceramics decreased from 2.0×10 −5 to 6.76×10 −6 mm 3 /Nm with 20 wt% SiC addition, resulting from the increased hardness and fracture toughness.