Grain Growth Behavior of Bi2O3-Doped ZnO Grains in a Multilayer Varistor
A novel bismuth-doped zinc oxide (ZnO) laminated structure is prepared in the present study. Seven layers with thickness ranging from 20 to 140 m are laminated together with platinum (Pt) inner electrodes. The growth of Bi2O3-doped ZnO grains within a very limited space between Pt electrodes is investigated. The grain growth behavior outside the confinement of electrodes is also studied for comparison purposes. At the beginning of sintering, a similar grain growth behavior is observed at different locations of the laminated structure. However, as sintering proceeds, the rate of grain growth within the Pt inner electrodes is decreased because of the decrease of available transportation paths. The grains between the electrodes then develop into a columnar shape as they make contact with the electrodes above and below them. Both the grain size and its distribution decrease with decreasing layer thickness.
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Document Type: Research Article
Affiliations: 1: Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan 106 2: Walsin Technology Corporation, Kaohsiung, Taiwan 700
Publication date: May 1, 2008