POSITIVE TEMPERATURE-COEFFICIENT OF RESISTIVITY IN BA1-XSRXPB1-DELTA CERAMICS(YO3)

The positive temperature coefficient of resistivity (PTCR) effect in B a1-xSrxPb1+yO3-delta ceramics is systematically studied. The influence of the preparation conditions on the PTCR properties is experimentall y tested. The PTCR effect in metallic-conducting BaPb1+yO3 is confirme d around 700-degrees-C. The temperature where the PTCR effect starts c an be shifted to a higher temperature range by substituting strontium for the A-site barium. By the enhancement of the sintering, the magnit ude of the PTCR effect was increased and the resisitivity was reduced. In addition to Pb(IV) in the perovskite structure, Pb(II) is detected at the grain boundary in the sintered body.