Carbon-ceramic composites refer to a special class of carbon based materials which cover the main drawbacks of carbon, particularly its proneness to air oxidation, while essentially retaining its outstanding properties. In the present paper, the authors report the results of a systematic study made towards the development of C-SiC-B4C composites, which involves the effects of compositional parameters, namely, carbon-to-ceramic and ceramic-to-ceramic ratios, on the oxidation behaviour as well as other characteristics of these composites. The C-SiC-B4C composites, heat-treated to 1400℃, have shown that their oxidation behaviour at temperatures of 800~1200℃ depends jointly on the total ceramic content and the SiC : B4C ratio. Good compositions of C-SiC-B4C composites exhibiting zero weight loss in air at temperatures of 800~1200℃ for periods of 4~9 h, have been identified. Composites with these compositions undergo a weight gain or a maximum weight loss of less than 3% during the establishment of a protective layer at the surface of carbon in a period of 1~6 h. Significant improvement in the strength of C-SiC-B4C composites has been observed which increases with an increase in the total ceramic content and also with an increase in the SiC : B4C ratio.

A study of partial carbonisation of green pitch fibres to temperatures in the range of 500-1000℃ was carried out on three precursors - a neat pitch and two polymer modified pitches, with a view to find out a suitable temperature at which the fibres acquire considerably improved toughness or handleability (compared to that in the green stage) for their subsequent processing into carbon fibres. A partial carbonisation temperature of 500-600℃ has been identified to result in a remarkable improvement in the toughness/handleability of the fibres in all the three cases. However, from techno-economical considerations, the neat pitch appears to provide the best precursor system for the production of pitch based carbon fibres.