Characterization of high thermal conductivity carbon fibers and a self-reinforced graphite panel

Extremely high thermal conductivity graphitic materials from mesophase pitch precursors (K-1100 fibers, four experimental high thermal conductivity fibers, and a ThermalGraph(R) panel) were examined utilizing X-ray diffraction (XRD) and high resolution field emission (FE) scanning electron microscopy (SEM). Of the four experimental fibers, two were produced from Amoco's standard petroleum pitch, and two were produced from an Amoco experimental pitch precursor. The low d-spacings, narrow peaks, and presence of three-dimensional reflections in the XRD patterns of the five fibers and the ThermalGraph(R) panel indicate that they are all highly graphitic. The thermal conductivities of these materials correlate best with the graphite inter-basal-plane spacing (d(002)). All of the materials studied appear very graphitic in high resolution SEM micrographs of their transverse fracture surfaces. Well-developed graphene layer planes are clearly seen. High resolution SEM examination of the ThermalGraph(R) panel shows that the precursor fibers have coalesced into a continuous three-dimensional structure. The result of this fiber fusion is a "self-reinforced", graphitic structure. (C) 1998 Elsevier Science Ltd. All rights reserved.