Ceramics with high electrical conductivity at room temperature

Ceramic materials are widely used in applications with chemical, mechanical or thermal challenges. Electrical functions of ceramics are mainly in the field of insulation. But specific fields like electrical heating, thermoelectrics or sensor applications require a defined electrical conductivity of ceramics. The paper considers different electrically conductive ceramics which are under development at Fraunhofer IKTS. The modification of electrical conductivity / resistance of silicon carbide, boron carbide, titanium suboxide and silicon nitride composites is investigated. Different approaches are required to tune the electrical resistance for applications like heating elements, electrodes or thermoelectric components. The different routes reach from variation of powder processing, sintering parameter adaption, change of sintering additives to dope semiconductors, tuning of composition of composite ceramics or generation of certain phase ratios of titanium suboxide Magneli phases. The paper describes those options and reports about the resulting electrical conductivity in relation to temperature.