| Summary: | 碩士 === 國立聯合大學 === 材料科學工程學系碩士班 === 95 === This study mainly explores the influences of additives on the sintering mechanism of ZnO. With 1wt%RuO2 or 1wt%Al2O3 additive, the sintering mechanisms of ZnO in the initial and intermediate stages are discussed. From the variations of the crystal structure parameters of doped ZnO analyzed by SEM, X-ray and TEM, it is observed that additives have different influences on the diffusion mechanism in the initial stage of sintering, 1wt%RuO2 is the volume diffusion, and 1wt%Al2O3 is the grain-boundary diffusion at 900℃. In the intermediate stage of sintering, 1wt% RuO2 added ZnO also have volume diffusion, its activation energy increases from 145 kJ/mol to 190 kJ/mol. When 1wt% Al2O3 is added, the second phase of ZnAl2O4 forms in the intermediate stage, Coble’s sintering model is not suitable for this sintering behavior. From TEM micrographs, additives are observed in both grain boundary and matrix of ZnO. The sample with 1wt% Al2O3 doping forms a second phase of ZnAl2O4 when the sintering temperature is as high as 1200℃. Both additives are able to decrease the diffraction angle, which corresponds to increasing the lattice parameters of ZnO crystal.
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