Major effects on varistor properties of ZnO–V2O5–MnO2–Nb2O5–Er2O3 ceramics with sintering changes

The microstructure and electrical properties of ZnO–V2O5–MnO2–Nb2O5–Er2O3 (ZVMNE) ceramics were investigated at different sintering temperatures (875–950 °C). The average grain size increased from 4.3 to 9.2 μm with the increase of sintering temperature. The breakdown field decreased from 7095 to 1256 V/cm with the increase of sintering temperature. The ZVMNE ceramics sintered at 900 °C exhibited a surprisingly high nonlinear coefficient (63). The donor concentration increased from 3.09 × 1017 to 7.99 × 1017 cm−3 with the increase of sintering temperature and the barrier height exhibited the maximum value (1.21 eV) at 900 °C.