Carbon fibre-reinforced carbon heating element prodn. - involves chemical gas phase infiltration with pyrolytic carbon

摘要

High precision heating elements of carbon fibre-reinforced carbon (CFC) are produced by subjecting the porous carbon matrix of CFC heating elements, produced in any desired geometry by conventional shaping and carbonising processes, to chemical gas phase infiltration (CVI/CVD) with pyrolytic carbon, the infiltration amount or the CVI reaction time being controlled so that the density (1.1-2.0 g/cu.cm) and thus the heating cross-section or the resistivity can be previously adjusted by the decreasing porosity to the exact requisite value in the range 5-50 micro-ohms. ADVANTAGE - The heating elements are simple and efficient to produce and have extremely high temp. strength at up to 2400 deg.C in vacuum and/or protective gas atmos. have high stiffness, have ductile fracture propeties, have very good chemical resistance (esp. oxidn. resistance), have high wear resistance, have low wt. and have an extremely wide range of resistance values.