Oxidation behavior of SiC ceramics synthesized from processed cellulosic bio-precursor

Oxidation behavior of Si/SiC ceramic composite synthesized from processed cellulosic bio-precursor was studied in dry air over the temperature range 1200-1350 degrees C. The material was synthesized from processed bio-precursors (bleached bamboo kraft pulp in the form of flat board of bulk density 0.58 g cm(-3)) and had a bulk density of 2.66 g cm(-3), porosity of 0.6 vol% and contents of Si and SiC phases of 39.1% and 60.3% (v/v) respectively. The process of oxidation could be described closely by a parabolic oxidation equation. An activation energy of 141.4 kJ/mol was obtained. Both the SiC and Si phases oxidized and the oxidation was mainly controlled by the transport of molecular oxygen through the growing oxide layer. Pre-oxidation at 1300 degrees C for 24 h in ambient air increased the strength of Si/SiC ceramics by around 46% because of the healing of the surface defects created during surface preparation by the oxide layer. (C) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.