Chemical vapor deposition and infiltration processes of carbon materials

The chemical vapor deposition (CVD) and the chemical vapor infiltration (CVI) processes of carbon materials are reviewed starting from the historical aspects and including the latest developments in the preparation of C/C composites. Our presentation is based on an analysis of the different types of reactors, of the composite materials with different types of pyrocarbon as matrices and a comparison between the different processes. In particular, the classical isothermal-isobaric technique and temperature or pressure gradient reactors, which lead to a higher deposition efficiency, are compared. A complementary aspect is the structural and physical analysis of the deposited pyrocarbons: they are considered as reproducible metastable phases which are obtained under non-equilibrium thermodynamic conditions. The final relevant point concerns the relationship between the process parameters and the type of pyrocarbon. In particular, the so-called rough laminar microstructure, useful for most composite applications, is described. (C) 2002 Elsevier Science Ltd. All rights reserved.