Microstructure and thermal conductivity of high thermal conductivity carbon/ carbon composites

Abstract

Porous carbon/carbon (C/C) composites prepared by pitch-based carbon fiber and mesophase pitch were densified by chemical vapor infiltration (CVI) and precursor impregnation process (PIP). After different heat temperature treatment (HTT), the unidirectional C/C composites and bidirectional C/C composites were obtained. The microstructure of C/C composites was investigated by SEM, XRD, and the thermal conductivity was analyzed based on the thermal conductivity mechanism. The results show that unidirectional C/C composites and bidirectional C/C composites have dense structures and excellent thermal conductivity along the fiber axis. After 3000 ℃ treatment, the structure of graphite flat layers become more distinct and the graphitization degree is increased by 18.84%, leading to higher thermal conductivity. Furthermore, the thermal conductivity in X direction and Y direction of the bidirectional C/C composites can be calculated from that of unidirectional C/C composites in X direction and Z direction.

Keywords

• carbon/carbon composites
• microstructure
• degree of graphitization
• thermal conductivity
• composites design