Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1525970 | Materials Chemistry and Physics | 2009 | 8 Pages |
Doped nanocrystalline zinc oxide powder with particle sizes ranging from 30 nm to 200 nm was synthesized by spray pyrolysis technique. The powder after calcination at 750 °C was consolidated and sintered using microwaves by employing different sintering schedules. The effect of heating rate on the density and electrical properties was studied. An optimized sintering temperature of 1100 °C was employed to obtain well-densified samples by both microwave and conventional processing. The sintered disks were characterized for their densities, microstructure, phase composition by X-ray diffraction and varistor properties like breakdown voltage, leakage current and non-linearity coefficient. The electrical properties obtained using microwave sintering technique was compared with those obtained on a conventionally sintered material as well as those of a commercially available product. The microwave sintered doped nanocrystalline ZnO yielded 98% dense bodies and a breakdown voltage of 9.6 kV cm−1, a leakage current of 0.25 μA cm−2 and a coefficient of non-linearity of 70 when compared to 4.3 kV cm−1, 1.2 μA cm−2 and 118 as measured for a conventionally sintered compact.