Influence of carbon on structure stability, mechanical and tribological properties of β-Si3(Cx,N1-x)4 silicon carbonitride

In this study, beta-Si-3(C-x,N1-x)(4) Silicon Carbonitride was prepared by Self-Propagation High-Temperature Synthesis (SHS). And the influence of carbon on structure stability, mechanical and tribological properties of beta-Si-3(C-x,N1-x)(4) were investigated. The results showed that the solubility of carbon in beta-Si-3(C-x,N1-x)(4) was about 10 wt%, beyond which cubic-SiC segregated out of beta-Si-3(C-x,N1-x)(4) to form beta-Si3N4/cubic-SiC composite. Regarding influences of carbon concentration on mechanical properties, the hardness of beta-Si-3(C-x,N1-x)(4) decreased from 1400 Hv to 1200 Hv with the increase of carbon concentration. Whereas, the fracture toughness of beta-Si-3(C-x,N1-x)(4) increased from 6.5 MPa.m(0.5) to 7.6 MP.m(0.5) with the increase of carbon concentration. The tribological property studies revealed the anti-wear performance of beta-Si-3(C-x,N1-x)(4) was enhanced by the increase of carbon concentration. The dominated wear mechanism could be attributed to the abrasive wear by fracture.