Microstructures and formation mechanisms of pyrocarbon in carbon/carbon composites

Pyrocarbon matrix of carbon/carbon composites was deposited on the surface of fibers via complex growth mechanisms. Different gas-phase equilibrium states result in various microstructures of pyrocarbon. In the present work, several gas-phase equilibrium states were distinguished by the mol ration R=[A]/[L], in which [A] represents the concentration of light aromatic hydrocarbons such as the benzene and [L] represents the concentration of linear hydrocarbons such as a ethylene and a acetylene. A G-T model was proposed to analyze the characteristic of pyrocarbon microstructures and then describe qualitatively the relation between the gas-phase components and the microstructures of pyrocarbon. The model can preferably explain microstructural transitions on the surface of fibers, which is helpful to predict and control the microstructures of pyrocarbon.