ELECTRICALLY CONDUCTIVE CERAMIC COMPOSITES

Basic results on the development of an electrically conductive, wear-a nd corrosion-resistant ceramic composite material are presented. From a closer examination of the dependence of the electrical conductivity on composition in the binary system ZrB2-B4C, we determined the percol ation threshold at which an interconnected network of electrically con ductive phase arises: for the system investigated, at a critical volum e fraction of about 10 up to 25 vol.% ZrB2, the electrical conductivit y increased rapidly and, above 40 vol.% ZrB2, an electrical conductivi ty similar to metals was observed (sigma(e) = 10(5)-10(7) S m(-1)). Ba sed on ZrB2 as major component and mainly B4C as minor component, a ce ramic composite material was obtained which exhibits a metallic electr on conductivity, a relative high resistance against oxidation and prom ising mechanical properties.