Chemical preparation and properties of high-field zinc oxide varistors

Chemical preparation methods were developed for high-field ZnO varistors which used precipitation techniques to prepare precursor powders. Varistors were made by sintering uniaxially pressed pellets in the range of 6750-740 0C in air. Properties of these varistors included electric fields (E) in the 10-100 kV/cm range at current densities (J) of 5 A/cm2, nonlinearity coefficients (α) greater than 30 for 2.5< or =J< or =5.0 A/cm2, and densities in the range of 65%-99% of theoretical depending both on sintering temperature and composition