INTERFACIAL MICROSTRUCTURES OF INTRABUNDLE IN AS-RECEIVED CARBON CARBON COMPOSITES PREPARED BY CVI/

A detailed study of the interfacial microstructures of the intrabundle s in as-received carbon/carbon composites prepared by CVI was performe d by high resolution electron microscopy. Two kinds of carbon fibers, high strength carbon fiber T300 and high modulus carbon fiber T-50, we re chosen for comparison. It was found that the interface between the carbon fiber and carbon matrix is not simply a mechanical pinning stru cture formed by pyrolytic carbons directly contacting the rough carbon fiber surface. A transitional interfacial layer between the carbon fi bers and the pyrolytic carbon matrix was observed which is referred to as induced microstructure. The graphitic degree and the crystallite s ize of the carbon fiber surface markedly affect the induced interfacia l microstructures. The more regular and graphitic the carbon fiber sur face, the more ordered and thicker the interface layer induced. (C) 19 98 Elsevier Science Ltd. All rights reserved.