ELECTRICAL-CONDUCTIVITY OF CERAMIC POWDERS AND PIGMENTS

Electrical conductivity of powder compacts has been predicted theoretically and verified experimentally using carbon black particles. Conductivity depends on the contact diameter between grains, and this can be calculated from the van der Waals attractive forces, knowing the size and elastic modulus of the particles. There is also a strong dependence on particle packing volume fraction φ and this has been modelled by a φ4 relation. The resulting analysis allows interpretation of experiments with various mechanical loads, with different particle sizes, in media which reduce the van der Waals interaction, and with ceramic particles which are covered with thin insulating layers. © 1990.