Effects of Ag particles on sintering and electrical properties of ZnO-based varistor

ZnO-based varistors containing Ag particles (abbreviated as Z–Ag) were prepared using the conventional solid-state reaction method. The sintering and electrical properties of Z–Ag composites show that the composites can be achieved at a lower sintering temperature (920 °C) relative to that of a commercial ZnO-based varistor. The composites possess non-ohmic behavior analogous to that of the ZnO-based varistor, and the nonlinear voltage can be easily controlled by the content of Ag particles in the ceramic matrix. Meanwhile, the dielectric constant and dissipation factor indicate that the composites have enhanced dielectric properties at room temperature with increasing content of Ag particles, especially at frequencies of 0.5–30 kHz. The mechanisms involved are discussed.