Nanofillers in ZnO based materials: a ‘smart’ technique for developing miniaturized high energy field varistors

The present work encompasses the strategic design, synthesis and development of high energy field ZnO varistors. The key aspect of the study involves the chemical synthesis of ZnO based nanorod nanofillers by a pH selective precipitation and reflux method. High field varistors were developed out of these crystalline nanofillers by employing them as fillers to the micron sized commercial varistor powder. A systematic investigation of the microstructural changes of the nanofiller added varistor samples were carried out under step-sintering and the normal sintering conditions. Comparative studies were also performed with the nano and micro counterparts. The influence of nanofillers in the varistor powder packing, grain structure refinement, grain size reduction and on the I–V properties were analyzed under the step-sintering conditions. Based on the performance analysis, the current study foresees ample opportunities for miniaturizing varistors with at least half the size of currently available varistors.