Sintering behavior and electrical properties of ZnO-PbO ceramics

ZnO doped with PbO in the range of 0.5 to 5 mol% was sintered at temperatures of 1273 to 1573 K, and microstructure and current-voltage characteristics were examined. Liquid Pb-rich Pb-Zn-O phase was penetrated among ZnO grains during sintering of ZnO-PbO composites, forming a grainboundary layer. However, PbO addition prevented densification during sintering due to the high vapor pressure of liquid PbO. The current-voltage behavior of the ZnO-PbO composites was non-linear. The resistivity of the ZnO-PbO composites decreased with increasing sintering temperature and approached that of pure ZnO. The non-linear coefficient of the ZnO-PbO composites is small, and hardly depends on the PbO content and the sintering temperature.