Synergistic Effects of Pr₆O₁₁ and Co₃O₄ on Electrical and Microstructure Features of ZnO-BaTiO₃ Varistor Ceramics

This paper investigated the effects of Pr₆O₁₁ and Co₃O₄ on the electrical properties of ZnO-BaTiO₃ varistor ceramics. The Pr₆O₁₁ doping has a notable influence on the characteristics of the nonlinear coefficient, varistor voltage, and leakage current where the values varied from 2.29 to 2.69, 12.36 to 68.36 V/mm and 599.33 to 548.16 µA/cm², respectively. The nonlinear varistor coefficient of 5.50 to 7.15 and the varistor voltage of 7.38 to 8.10 V/mm was also influenced by the use of Co₃O₄ as a dopant. When the amount of Co₃O₄ was above 0.5 wt.%, the leakage current increased from 202.41 to 302.71 μA/cm². The varistor ceramics with 1.5 wt.% Pr₆O₁₁ shows good nonlinear electrical performance at higher breakdown voltage and reduced the leakage current of the ceramic materials. Besides, the varistor sample that was doped with 0.5 wt.% Co₃O₄ was able to enhance the nonlinear electrical properties at low breakdown voltage with a smaller value of leakage current.