Influence of ZnO addition on the sintering properties of SnO2 electrodes

The effect of ZnO doping in SnO2 was investigated for electrodes. Zinc oxide in different concentration, 0.5-5 wt%, was added to tin dioxide powder prepared by a coprecipitation method. The products were characterized by powder X-ray diffraction, transmission electron microscopy, and by section scanning electron microscopy. The resistivity of those electrodes was measured with KEITHLEY236 high-resistance instrument. It was found that ZnO was expected to increase the electrical conductivity of SnO2 ceramic. However, the range of solid solution of ZnO into SnO2 lattice was found to be limited as it rapidly segregated to form secondary phases. Concentrations as high as 5 wt% of ZnO lead to the formation of a ZnSnO3 phase whose presence yielded a non-linear electrical response that hinders the donor effect of zinc oxide.