Effect of pre-synthesis of Bi2O3  and Sb2O3  on the properties of ZnO varistor ceramic

ZnO varistor ceramics were fabricated using the solid-state sintering method. The effects of Bi2O3 and Sb2O3 presynthesis on the microstructure and electrical properties of varistor ceramics were investigated. Results demonstrated that high-purity BiSbO4 material was successfully synthesized at 700 ℃, and varistor ceramics were subsequently fabricated. Comparing with the original preparation method, the voltage gradient increased by 44 V/mm, leakage current decreased to 0.072 μA·cm-2, and the nonlinear coefficient increased by 29. Furthermore, the sample exhibited higher density and excellent resistance to lightning current breakdown, with ceramic current-carrying capacity improving by 10 %. These findings provide guidance for developing high current-carrying capacity ZnO varistor ceramics.