An Ultralow Concentration of Cr2O3 Dopants-Driven Lower Temperature Sintering ZnO-Based Varistor Ceramics
Low working voltage-driven ZnO-based varistor ceramics play an important role in the multilayer chip varistors, which require a low sintering temperature of ZnO varistor for its low energy consumption. Herein, a remarkable reduction of the sintering temperature from the usual 1100–1300 °C to 950 °C is successfully achieves in the ZnO ceramics via a certain 0.05 mol% of Cr 2 O 3 dopants. The underlying mechanism is found to be involved with the formation of basal-plane inversion boundaries between the ZnO grains, which can promote the rapid grain growth within the ceramics. Furthermore, the ZnO varistors with 0.05 mol% Cr 2 O 3 dopant exhibit excellent performance. A low breakdown voltage of 416 V mm −1 , a high nonlinear coefficient of 39, and a low leakage current of 3.4 μA are obtained simultaneously. This work presents an effective and promising approach for the cost-efficient preparation of high-performance ZnO-based varistors, which have particular significance for the application of multilayer chip varistors with low working voltage.
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