Maity, Anwesha and Kalita, Dipul and Kayal, Tarun Kumar and Goswami, Tridip and Chakrabarti, Omprakash and Maiti, Himadri Sekhar and Rao, Paruchuri Gangadhar (2010) Synthesis of SiC ceramics from processed cellulosic bio-precursor. Ceramics International, 36 (1). pp. 323-331. ISSN 0272-8842

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Abstract

Synthesis of SiC ceramic from processed cellulosic bio-precursor was investigated. Bamboo (Bambusa tulda Roxb.) plants abundantly available in the Jorhat district of Assam, India, were selected for extraction of fibers following Kraft pulping method and bleached bamboo pulp fibers were suitably cast in the form of rectangular boards. Coir fibers available in the Alleppy district of Kerala, India, were initially digested with dilute alkali, mixed with cellulose acetate solution, air dried and then hot-pressed at 140 +/- 5 degrees C under 2.0-2.5 MPa pressure to make rectangular boards. Well-characterized processed bio-precursors were pyrolysed at similar to 800 degrees C under flowing N(2) atmosphere to prepare the bio-carbonaceous preforms (carbon templates) which showed nearly uniform shrinkages in all directions. Coir fiber composite board carbon showed lower pyrolytic weight loss (similar to 66%), higher density (0.49 g cm(-3)), lower porosity (similar to 58%) and narrower pore diameter (10 mu m) compared to the cast bamboo pulp fiber board carbon. The carbon samples showed perfect retention of fibrous morphological features of hierarchically grown bio-structures. Ceramization of carbon templates could be done by reactive melt silicon infiltration into porous channels at similar to 1600 degrees C under vacuum. The final ceramics were adequately dense (%theoretical density > 99%), showed negligible linear dimensional changes (indicating net-dimension formation capability), presence of crystalline Si and SiC phases and duplex microstructure with complete preservation of fibrous architecture of plant bio-structure. The Si/SiC ceramic composite synthesized from coir fiber board gave room temperature 3-point flexural strength and Young's modulus values of 121 MPa and 276 GPa, respectively. Both the ceramic composites showed adequate oxidation resistance during heating at 1300 degrees C for 7 h in air. (C) 2009 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Item Type:	Article
Uncontrolled Keywords:	Processed bio-precursor; Fibrous morphology; Mechanical property; SiC ceramic
Subjects:	Engineering Materials
Divisions:	UNSPECIFIED
Depositing User:	Bidhan Chaudhuri
Date Deposited:	14 Feb 2012 07:12
Last Modified:	14 Feb 2012 07:12
URI:	http://cgcri.csircentral.net/id/eprint/806

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