High Thermal Conductivity Carbon/Carbon Composites

摘要

The objective of this project was to develop a lowcost, high thermal conductivitycarbon/carbon composite with a mesophase pitch-based matrix. A low-cost, continuous powder coating process was developed which can produce a flexible pre-impregnated pitch-based towpreg. A combination of a pressure-carbonization technique and heat treatment of the mesophase pitch was utilized to enhance composite properties by increasing the composite density. Three different fibers, T300 PAN-based, P55 pitch-based, and an experimental high thermal conductivity mesophase pitch-based, were incorporated as the filler phase in the composites. The thermal conductivity of the graphitized T300/AR-120 and the P55/AR-120 composites was 80.5 and 135.5 W/m-K, respectively. The composites reinforced with the experimental ribbon fibers exhibited 3-D anisotropy, with a thermal conductivity, transverse to the fibers, of 213.5 W/m-K, higher than that parallel to the fibers, 145 W/m-K. These results indicate that fiber shape can affect matrix properties in carbon/carbon composites. Using finite element methods, a model was developed to predict the effect of specific material variables, such as fiber fraction, fiber structure, matrix structure, fiber/matrix interface, and void fraction, on the thermal conductivity of the composite. p2.