Electrical resistivity of porcelain in relation to constitution

The electrical resistivity of porcelain samples has been measured from room temperature to 1200 degrees C and it was found to depend on the concentrat ion of the phases as well as the size and size-distribution of mullite crys tals. The resistivity of porcelain was found to decrease with increase in a mount, size and asymmetry of size-distribution of mullite crystals but incr ease with increase in quartz, cristobalite and glass content. Irrespective of constitution, resistivity of porcelain decreased with rise in temperatur e from about 10(13) ohm-cm at room temperature to about 10(4) ohm-cm at 120 0 degrees C. The change in electrical resistivity of porcelain was primaril y controlled by the defect structure of mullite and the composition and vis cosity of the glassy phase. (C) 1998 Elsevier Science Limited and Techna S. r.l. All rights reserved.