CVD and CVI of pyrocarbon from various precursors

The control of pyrocarbon Chemical Vapor Infiltration (CVI) is a key issue in the processing of high-performance C/C composites with applications in aerospace parts and braking technology. For years, the precise investigation of deposition kinetics and pyrocarbon nanometer-scale anisotropy has been rehearsed in CVD and several variants of CVI with various pore sizes, and using mostly propane, propylene, and methane as source precursors. A literature survey and the analysis of recent experimental data have helped to understand better the role of gas-phase intermediate species in the various nanotextural transitions ; a coherent modeling frame, suitable for propane, propylene, and methane – the latter having a neatly lower reactivity – has been set up and tested against experimental results from independent teams. The relation between nanotexture and processing conditions are then explained.