Effects of Y_(2)O_(3) on the microstructure and electrical properties of Pr-ZnO varistors

摘要

Effects of Y_(2)O_(3) contents on the microstructure and electrical properties of Pr_(6)O_(11)-based ZnO varistor have been studied. The varistor voltage (V_(1mA)) and the nonlinear exponent (α) increased with increasing Y_(2)O_(3) contents, whereas the dielectric constant decreased. Y-rich phase segregated at nodal points in grain boundaries. The average grain size decreased with increasing Y_(2)O_(3) content. The specimen with 4.0 mol% Y_(2)O_(3) sintered at 1285℃ exhibited the highest nonlinear exponent (α=77) with the dielectric constant, ～352 at 1 kHz.