Optimization of the composition and sintering conditions of high-voltage ZnO varistor ceramics

Abstract

This paper presents a study aimed at optimizing the composition and sintering conditions of highvoltage ZnO varistor ceramics. We demonstrate that, with allowance for the cost of starting materials, the optimal composition of high-voltage ZnO varistor ceramics is as follows (wt %): ZnO, 90; Bi₂O₃, 2.76; Sb₂O₃, 1.92; Al₂O₃, 3.32; and Co₂O₃, 2. The optimal sintering conditions are isothermal holding at a temperature of 975°C for 2 h. The ceramics thus prepared have V_b = 4.5 kV/mm, α = 50, I_l = 1.1 μA/cm², density ρ = 5.67 g/cm³ (relative density of 96.1%).