| Abstract Scope |
For cost-effective production of dense silicon carbide (SiC) ceramic parts, pressureless sintering of SiC ceramics at lower temperatures is preferred. This study suggests a new additive composition based on AlN–Y2O3–CeO2–MgO that leads to successful densification of SiC without applied pressure at a temperature as low as 1850°C. The effect of sintering temperature on the mechanical and thermal properties of SiC ceramics sintered with the new quaternary additive was investigated. Fracture toughness of the SiC ceramics continuously increased with increasing sintering temperature because of the growth of platelet SiC grains at temperatures ≥ 1800°C. In contrast, the flexural strength and hardness showed maxima at 1900°C due to the decreased density and increased grain size at higher sintering temperatures. Typical sintered density, fracture toughness, hardness, and flexural strength of the 1850°C-sintered SiC ceramics were 99.1%, 4.7 MPa·m1/2, 23.5 GPa, and 328 MPa at room temperature, respectively. |