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We have studied the combined effects of the templated grain growth and magnetic alignment processes on sintering, anisotropic sintering shrinkage, microstructure development and texture in ZnO ceramics. Suspensions of 0-10 vol % ZnO template particles were slip cast in a 12 T rotating magnetic field. Sintering and texture characteristics were investigated via thermomechanical analysis and electron backscatter diffraction, respectively. Sintering as well as texture characteristics depend on template concentration. For the studied ZnO system, there is a critical template concentration (2 vol % in this study) above which densification is limited by the templates owing to constrained sintering. Below this limit, the densification is enhanced and the anisotropic shrinkage is reduced, which is attributed to densifying characteristics of the templates.

Textured ZnO-based varistors were produced by using templated grain growth technique (TGG). Rod-like ZnO particles which used as templates in TGG were synthesized by homogeneous precipitation method from the 0.01 M zinc nitrate and 0.0125 M hexamethylenetetramine (HMT) solutions at 90ºC. The templates were aligned by tape casting of ZnO based aqueous slurries. A modified tape caster with a comb blade was used for the tape casting process. Texture development in the green and sintered samples was investigated by x-ray diffractometer (XRD) and scanning electron microscope (SEM).

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