Electrically conductive carbon-coated ceramic fiber media

Abstract

Porous ceramic fiber composites were coated with pyrolytic carbon by the decomposition of either propane or infiltrated phenolic resin in a nitrogen atmosphere at 800-900°C. The amount of carbon coating was varied to tailor the electrical conductivity of the carbon-coated composites. The electrical and thermal conductivity of the composites were measured at room temperature using a two-point method and a hot-wire one, respectively. Up to 30 wt% pyrolytic carbon, the electrical conductivity σ showed linearly increasing tendency and was fitted by the effective conductivity according to the parallel rule of a mixture σ =ΣV i ·σ i with an effective conductivity of pyrolytic carbon σ c and volume fraction of coated carbon V c . The electrical conductivity of coated carbons prepared from propane at 900°C and phenolic resin at 800°C was of the order of 10° and 10 -1 S cm -1 , respectively.