CHEMICAL VAPOR-DEPOSITION OF VERY THIN COATINGS ON CARBON-FIBER BUNDLES

The continuous deposition of thin coatings of refractory materials on carbon fibre rovings is considered as the impregnation of an endless cylinder with slit-like pores in the direction parallel with the cylinder axis. From such a model, the limits of process parameters for the simultaneous coating of all individual monofilaments are derived. In detail a correlation between the deposition parameters and the resulting layer thickness is discussed for a deposition with high and low conversion respectively. The deposition of thin (0.02 to 0.5-mu-m) SiC and TiN layers on carbon monofilaments is described in systematic experiments using a steady state laboratory equipment. The effect on the mechanical properties of the reinforcement fibers is shown.