The influence of Si3N4 on the microstructure, mechanical properties and the wear performance of TiB2–SiC synthesized via spark plasma sintering

Abstract

This research is directed to examine the influence of silicon nitride additive (2.5–5%) Si3N4 on the microstructure, sinterability, densification, and mechanical features of (TiB2–10SiC) and (TiB2–20%SiC) and, more uniquely, the impact of the aforementioned properties on the wear behaviour of the resulting composites. Higher densification with optimal hardness and fracture toughness of 99.4%, 24.9 GPa and 4.63 MPa·m1/2 was achieved respectively when 2.5% Si3N4 was introduced into TiB2–20SiC composite. Microstructural observation depicts that in-situ phases such as TiC contributed to the enhancement of the relative as well as the mechanical properties. However, increasing the sintering additive of Si3N4 to 5% in the composite lowers the relative density, consequently lowering the hardness of the composites. More also, the wear behaviour of the fabricated composites revealed that the composite having enhanced densification and hardness contributed to its improved wear resistance of the resulting composites.

Keywords

• TiB2
• SiC
• Si3N4
• Microstructure
• Mechanical properties
• Wear performance