| Summary: | In the current study, TiO2-based thick film varistors (TFVs) doped with 2.5 mol% Ta and various concentrations of Ca were prepared by using screen-printing technique. The effects of the different Ca concentrations (0.5–3.0 mol%) on microstructure enhancement, nonlinear behavior, and dielectric properties of TiO2-based TFVs were investigated at 2.0 mol% doping concentration. Results showed a Vb value of 513 V, a resistivity value of 157.2 kΩ.cm and an α value of 62. Furthermore, high εr value and low tan δ value at low-frequency range detected that the grain boundaries formed in 2.0 mol% doping concentration samples are good. Therefore, the doping amounts can be used to control the grain size and different properties of (Ca, Ta)-doped TiO2 TFVs with improved structural, electric, and dielectric properties. Keywords: Thick film varistor, Grain boundary, Electrical properties, Microstructure, Dielectric behaviors
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