Aging characteristics of ZnO-V2O5-based varistors for surge protection reliability

The effect of sintering temperature on clamping characteristics and pulse aging behavior of V2O5/MnO2/Nb2O5 co-doped zinc oxide varistors was systematically investigated at 875-950 degrees C. Experimental results related to varistor effect showed that the breakdown field decreased dramatically from 6830 to 968 V/cm with the increase in the sintering temperature and the non-ohmic coefficient exhibited a maximum (49.5) at 900 degrees C in the sintering temperature. Varistors sintered at 900 degrees C exhibited the best clamp characteristics for the pulse current of 1-100 A, with the clamp voltage ratio of K= 1.86-2.77. Varistors sintered at 875 degrees C exhibited the strongest stability; variation rates for the breakdown field, for the non-ohmic coefficient, and for the leakage current density were -14.2%, -63.6%, and 59.0%, respectively, after application of a multi-pulse current of 100 A. (C) 2014 Elsevier Ltd. All rights reserved.