Raman microprobe spectrometry of carbon/carbon composites with differently-textured pyrolytic carbon matrices

The microstructure of carbon/carbon composites obtained by chemical vapor infiltration of carbon-fiber felts was studied comparatively by means of Raman spectroscopy, polarized light microscopy (PLM), scanning electron microscopy (SEM), and X-ray diffraction. The matrices, which are homogeneously textured according to PLM, exhibit pronounced spatial structural gradients at the sub-m scale if investigated by means of Raman microprobe spectrometry. The Raman and SEM observations demonstrate that the high-temperature treatment correlates with the increasing development of the graphitic ordering in low- and high-textured pyrolytic carbon matrices.