Effects of the sintering temperature on the oxygen adsorption in ZnO ceramics

Changes in electrical resistivity due to oxygen adsorption for samples prepared at different sintering temperature are presented. It was found that samples cooled in steps from the sintering temperature show a higher resistivity and that oxygen indiffusion is faster in quenched samples and in samples sintered at low temperatures. Two mechanisms were determined to be responsible for an increase in the sample resistivity. First, oxygen adsorption at grains surfaces produces a rapid increase in resistivity and then a slow change in the response due to oxygen diffusion into the grains. (C) 1999 Elsevier Science Limited. All rights reserved.