Deposition mechanism and microstructure of pyrocarbon prepared by chemical vapor infiltration with kerosene as precursor

Large-size carbon/carbon composites (phi 450 x phi 230 x 15 mm(3)) have been produced by chemical vapor infiltration with kerosene as precursor. The microstructure of pyrocarbon was examined by polarized light microscopy and scanning electron microscopy. The infiltration kinetics was analyzed to investigate the infiltration rate limitation by parameters such as temperature. The results show that rough laminar carbon constitutes the majority of the matrix at a medium temperature (about 1100 degrees C), while smooth laminar and isotropic structures occur at temperatures lower than 1000 degrees C and higher than about 1200 degrees C, respectively. The apparent activation energy of kerosene decomposition in the temperature range 900-1200 degrees C is about 125.6 kJ/mol. (C) 2009 Elsevier Ltd. All rights reserved.