Continuous Liquid Phase Coating of Carbon Fibers –Protective Carbon Layers Derived from Coal Tar Pitch andPhenolic Resins

摘要

In manufacturing of carbon-carbon (CC) or reaction bonded C-SiC (RB-SiC) composites the use of pyrolytic carbon (Pyc)rncoated carbon fibers as reinforcement material is widespread. Thin carbon layer provides protection against corrosive liquidrnmetals and the fiber-matrix interface can be taylored in order to optimize the mechanic properties of the composite material.rnDeposition of carbon layers by continuous liquid phase coating(CLPC) is an attractive and cost efficient alternative torndeposition of pyrolytic carbon by a state-of-the-art CVD process. 12 k multifilament carbon fiber strands were impregnatedrnwith diluted solutions of carbon precursors (phenolic resins or pitch). After subsequent curing and pyrolysis monofilamentrncoated fibers with a coating thickness of 50-200 μm were yielded. The IFKB pilot plant continously produces commercialrntype fiber coils, sufficient for investigations on fiber quality and processibility in composite manufacturing. The influence ofrncuring, pyrolysis and calcination temperature, as well as fiber turnover, precursor type and precursor concentration wasrnstudied in order to obtain maximum mechanical properties.