Conversion of raw rice husks to SiC by pyrolysis in nitrogen atmosphere

• Published in: Journal of the European Ceramic Society Vol. 18; no. 2; pp. 147 - 152
• Main Authors: Krishnarao, Raghavarapu Venkata, Mahajan, Yashwant Ramchandra, Kumar, Thammana Jagadish
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1998; Elsevier
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Whiskers and dendrites (growth,structure, and nonelectronic properties); Pressure dependence; Pyrolysis; Inorganic compounds; Silicon carbide; Whiskers; Controlled atmospheres; Binary compounds; Crystal growth from vapors; Experimental study; Rice by product; Ceramic materials
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/S0955-2219(97)00093-9

Raw rice husks without precoking were directly pyrolysed in a graphite resistance heating furnace at 1100–1400 °C in nitrogen atmosphere. The furnace chamber pressure was varied from atmospheric pressure (14.7 Psi or 101.3 KPa) to 24 Psi (165 KPa). Considerable quantities of SiC whiskers were formed at 1200–1400 °C. Small quantities of Si 2N 2O were also formed at 1100 and 1200 °C. No Si 3N 4 was formed. The increase in chamber pressure has resulted in (i) an increase in the crystallization of silica and carbon in rice husks, (ii) decrease in the formation of SiC whiskers. Pyrolysis in nitrogen atmosphere resulted in the formation of good quality (needle type) SiC whiskers.