Structure and Properties of Pyrolytic Carbon: Recent Developments and Hidden Potentials

Recent developments on the relationship between the complex microstructure of pyrolytic carbon coatings and the pyrolysis conditions are reviewed. Pyrolytic carbon coatings deposited on carbon fibers and non-carbon substrates are studied comparatively by light microscopy, scanning electron microscopy and transmission electron microscopy combined with selected-area electron diffraction. Optically uniform coatings exhibit pronounced gradual changes in texture degree of graphitic crystallites at the sub-micrometer-scale if investigated by electron diffraction. The thickness of the reaction layer at the pyrolytic carbon /carbon fiber interface depends on the carbon fiber crystallization degree. The porosity of coatings is influenced by the reactor cooling rate. All these studies suggest a large potential of pyrolytic carbon for the design of multifunctional coating materials.