Densification of two-dimensional carbon/carbon composites by pitch impregnation

Densification of two-dimensional phenolic resin-based C/C composites was pe rformed by melted petroleum pitch impregnation under a uniaxial mechanical pressure followed by recarbonization at atmospheric pressure. With increasi ng number of densification cycle, decrease in open porosity and increase in bulk density were obtained. However, densification. efficiency was found t o decline with the densification cycles. In the later stage of the densific ation cycles, voids closure resulted in a decrease in the apparent density, and much lower densification efficiency was obtained. Results of flexural test indicated that both strength and modulus increased with increasing num ber of densification cycle. Significant improvement in mechanical performan ce was found when an intermediate high temperature heat treatment of 2000 d egreesC was used between densification. cycles. (C) 2001 Elsevier Science B .V. All rights reserved.