A novel bismuth-doped zinc oxide (ZnO) laminated structure is prepared in the present study. Seven layers with thickness ranging from 20 to 140 lm are laminated together with platinum (Pt) inner electrodes. The growth of Bi 2 O 3 -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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In the present study, the effect of Bi 2 O 3 and Bi 2 O 3 +Sb 2 O 3 additions on the size distribution of ZnO grains is investigated. Without the usage of a powder bed, the addition of Bi 2 O 3 provides a transient liquid phase that enhances the densification. The residual Bi segregates alters the surface/grain boundary energy ratio, which encourages the ZnO grains to grow. The size variation is also increased. The addition of both Bi 2 O 3 and Sb 2 O 3 induces the formation of pyrochlore, spinel and inversion boundary. Their presence reduces not only the average grain size, but also the size variation.

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