CARBON FIBERS FROM VAPOR-PHASE CVD REACTION

0 CARBON FIBERS FROM VAPOR-PHASE (CVD) REACTION 

The direct growth of carbon fibers from the vapor-phase has been investigated for a number of years and the potential for producing a economically viable material with properties matching those of existing PAN or pitch-based fibers appears good.t °l P l 

Vapor-phase fibers are produced by the catalytic decomposition of a hydrocarbon such as methane or benzene. The seed catalysts are iron particles or iron metallo-organics such as ferrocene, (C5H5)2Fe. Growth occurs in the temperature range of 1000 -1150°C. 

The fibers still have a large spread intheirtensile strength (3000 - 8000 MPa). However, the higher values compare favorably with those of high-strength PAN-based fibers (see following section). 

Vapor-phase fibers are only produced in short lengths at the present time. Maximum reported length is 50 mm with diameters from 0.5 - 2 pm. Such short-length fibers would be suitable for the random reinforcement of composites and in the production of carbon-carbon (see Ch. 9). 

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