Wear and high-temperature stability of TiCN-WC-Co-Cr3C2-HfC-Si3N4 cermets

Abstract

This work reports the wear and high-temperature stability of TiCN-WC-Co-Cr₃C₂-HfC-Si₃N₄ cermets developed by spark plasma sintering (SPS). The addition of Si₃N₄ in the range of 5 wt. % to 15 wt. % in TiCN-WC-Co-Cr₃C₂-HfC cermet composition showed hardness of the cermets in the range of 10.2±0.05 to 11.7±0.05 GPa. Among the three cermets developed, 60TiCN-15WC-10Co-5Cr₃C₂-5HfC-5Si₃N₄ possessed a hardness value of 11.7±0.05 GPa and fracture toughness value of 15.1±3.5 MPa√m. The wear behaviour of the cermets was studied using a pin-on-disc machine with cermets as a pin on EN 31 steel counter disc material with three different sliding velocities in the range of 0.23–0.35 m/s, at a constant normal load of 20 N for a duration of 5 min. 60TiCN-15WC-10Co-5Cr₃C₂-5HfC-5Si₃N₄ cermet showed a high wear resistance at all the three sliding velocities compared to the other cermet composition. High-temperature stability of the cermets was assessed by heating the cermet samples to 600 °C, 800 °C and 1000 °C and holding them for about 4 h followed by cooling within the furnace itself. All the three cermets were stable up to 800 °C. Cermet 60TiCN-15WC-10Co-5Cr₃C₂-5HfC-5Si₃N₄ showed less affinity for oxidation after heating, and hence, it has good thermal stability than other cermet compositions.