Sintering behavior and electrical properties of porous (Ba,Sr)(Ti,Sb)O3 ceramics produced by adding corn-starch

Porous (Ba,Sr)(Ti,Sb)O3 ceramics were fabricated by adding corn-starch (1–20 wt.%) and effect of sintering condition on the PTCR characteristics of the porous ceramics was investigated. The room-temperature electrical resistivity of the (Ba,Sr)(Ti,Sb)O3 ceramics was decreased and increased with increasing sintering temperature and sintering time, respectively. The former was attributed mainly to the increase of grain size as well as the partial decrease of the porosity, and the latter was due to the increase of the electrical barrier height of grain boundaries. The sample sintered at 1450 °C for 1 h showed the excellent PTCR characteristics, i.e. the lowest room-temperature resistivity (8.4×10 Ω cm) with the high ratio of maximum resistivity to minimum resistivity (6.3×105).