Microstructure and electrical properties of Y 2O 3-doped ZnO-based varistor ceramics prepared by high-energy ball milling

Abstract

Y 2O 3-doped ZnO-based varistor ceramics were prepared using high-energy ball milling (HEBM) and low-temperature sintering technique, with voltage-gradient of 1934–2197 V/rhm, non-linear coefficients of 20.8–21.8, leakage currents of 0.59–1.04 μA, and densities of 5.46–5.57 g/cm 3. With increasing Y 2O 3 content, the voltage-gradient increases because of the decrease of ZnO grain size; the non-linear coefficient and the leakage current improve but the density decreases because of more porosity; the donor concentration and density of interface states decrease, whereas the barrier height and width increase because of the acceptor effect of Y 2O 3 in varistor ceramics.