Chemical vapor-infiltrated graphite

The molded plate with the large volume of pores was further coated by chemical vapor-infiltrated (CVI) graphitic carbon at 1,500°C with 5 kPa... 

There are two basic types of processes used to make CAMCs. The first is chemical vapor infiltration (CVI). CVI is a process in which gaseous chemicals are reacted or decomposed, depositing a solid material on a fibrous preform. In the case of CAMCs, hydrocarbon gases like methane and propane are broken down, and the material deposited is the carbon matrix. The second class of processes involves infiltration of a preform with polymers or pitches, which are then converted to carbon by pyrolysis (heating in an inert atmo-sphere). After pyrolysis, the composite is heated to high temperatures to graphitize the matrix. To minimize porosity, the process is repeated untU a satisfactory density is achieved. This is called densification. Common matrix precursors are phenolic and furan resins, and pitches derived from coal tar and petroleum. 

Highly crystalline hexagonal boron nitride layers can be formed on graphite layers which have been obtained from the CVD of benzene [128]. Low-pressure CVD originating from 2,4,6-trichloroborazine on graphite, metallic, and oxide ceramic substrates at 1050°C leads to dense, amorphous boron nitride deposits [129] see also [130]. Ceramics are frequently coated or infiltrated with a-BN by the different chemical vapor deposition (CVD) methods already... 

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