Ceramics-Silikáty 47 (3) 116-119 (2003)

THE EFFECT OF THE PbO ADDITION ON THE SINTERING OF ZnO

H. Ö. Toplan, H. Erkalfa, O. T. Özkan

The microstructural evolution and densification for the ZnO-PbO system were studied. Specimens were prepared by the mixed oxide route, and sintered at temperatures in the range of 1000-1300°C. The bulk densities of the PbO-added ZnO samples increased from 1000 to 1100°C. In sinterings above 1100°C, the bulk density was decreased almost linearly due to lead oxide evaporation except in 2.5 mol% PbO-added ZnO samples. The ZnO-PbO ceramics have a two phase microstructure comprising ZnO grains and a Pb-rich phase at the grain boundaries. The average grain size of ZnO increases with the PbO addition up to 7.5 mol% PbO addition but, the excess PbO addition decreases the grain size. This is due to the change in the grain growth mechanism from the solution precipitation in the liquid-phase to that of an ion diffusion mechanism in a thicker layer of liquid .

Keywords: Densification, Liquid Phase Sintering, ZnO grain growth