Journal of Materials Science

, Volume 33, Issue 10, pp 2537–2549

Synthesis of beta silicon carbide powders using carbon coated fumed silica

Authors

  • Rasit Koc
    • Department of Mechanical Engineering and Energy ProcessesSouthern Illinois University
  • Sai V Cattamanchi
    • Department of Mechanical Engineering and Energy ProcessesSouthern Illinois University
Article

DOI: 10.1023/A:1004392900267

Cite this article as:
Koc, R. & Cattamanchi, S.V. Journal of Materials Science (1998) 33: 2537. doi:10.1023/A:1004392900267

Abstract

The synthesis of beta silicon carbide (β-SiC) powders by carbothermic reduction of carbon coated silica and silica mixed with carbon black was investigated. The production of β-SiC powders by using carbon coated silica consists of two steps. The first step is to prepare the carbon coated silica precursor by coating fumed silica particles with carbon by pyrolytic cracking of a hydrocarbon gas (C3H6). This provides intimate contact between the reactants and yields a better distribution of carbon within the fumed silica. Fumed silica was also mechanically mixed with carbon black for comparison. Both starting mixtures were reacted in a tube furnace for 2 h at temperatures of 1300°C to 1600°C in 1 l min-1 flowing argon. The reaction products were characterized using weight loss data, X-ray diffraction (XRD), a BET surface area analyser, oxygen and free carbon analysis and transmission electron microscopy (TEM). The carbon coating process resulted in a more complete reaction, purer product and high yield SiC powders with very little agglomeration at temperatures of 1500°C and 1600°C. The β-SiC powders produced at 1600°C for 2 h in argon gas flow have oxygen content of 0.3 wt%, a very fine particle size 0.1–0.3 μm and uniform shape. © 1998 Chapman & Hall

Copyright information

© Chapman and Hall 1998