Influence of sintering conditions on the electrical properties and the PTCR effect of the multilayer Ba1.005(Ti1−xNbx)O3 ceramics with Ni internal electrode

Abstract

The effects of the Nb-dopant content and the sintering conditions on the electrical properties and the positive temperature coefficient of resistance (PTCR) effect of Ba1.005(Ti1−xNbx)O3 (BTN) ceramics were investigated, which were sintered at 1,070–1,220 °C for 0.5–6 h in a reducing atmosphere and then re-oxidized at 600–750 °C for 1 h. The results indicated that both the sintering temperature and sintering time affected the electrical properties and the PTCR effect of the multilayer BTN samples, whose room-temperature (RT) resistance first reduced and then increased as a function of the donor–doped concentration at all sintering temperature; moreover, the higher the sintering temperature was, the lower the critical dopant concentration. The BTN ceramics showed a remarkable PTCR effect, with a resistance jump greater by 3.3 orders of magnitude, along with a low RT resistance of 0.3 Ω at a low reoxidated temperature of 600 °C after sintering in a reducing atmosphere.