Densification of SiC by colloidal processing and SPS without sintering additives

Abstract

Silicon carbide is one of the most important ceramics used as structural and functional materials in a wide variety of applications. Many studies have reported the densification of SiC using oxide and nonoxide additives such as the Al₂O₃, B₄C and Al–B–C system. However, it is difficult to densify SiC at temperatures below 2000°C without sintering additives even if spark plasma sintering (SPS) is used. The authors attempted to densify SiC using colloidal processing and SPS without sintering additives. A commercially available SiC powder with the average particle size of 0·55 μm was used as the starting material. The densities of the green body prepared by slip casting and the sintered body by SPS were 65·5 and 98·7% respectively.

Keywords:

• Packing density
• Slurry
• Dispersion
• Bimodal particle size distribution
• Sintering atmosphere

Acknowledgements

The authors wish to thank Dr H. Tanaka and Dr T. Nishimura of the National Institute for Materials Science for their fruitful discussions.