Effect of pre-calcination of Bi2O3 and Sb2O3 on the densification and varistor properties of low-temperature sintered ZnO-Bi2O3 ceramics

This study utilized a conventional solid-state reaction method to sinter Bi2O3-Sb2O3-Co3O4-Mn3O4-Nb2O5 zinc oxide varistors at low temperatures of 860-880 degrees C. The pyrochlore phase occurs at temperatures ranging from 700 to 900 degrees C, influencing densification kinetics. The liquid-phase former, Bi2O3, is con-sumed and reacts to form the pyrochlore secondary phase Zn2Bi3Sb3O14, which inhibits the densification at low temperatures. Bi2O3 and Sb2O3 were pre-calcined at 550 degrees C to reduce secondary phase Zn2Bi3Sb3O14 formation and Bi2O3 consumption in this study. It was observed that pre-calcination of Bi2O3 and Sb2O3 at 550 degrees C successfully reduced the formation of the secondary phase Zn2Bi3Sb3O14, lowered the densification temperature of the ZnO-Bi2O3 varistor and improved its performance.

Automated summary

This study used a conventional solid-state reaction method to sinter zinc oxide varistors containing Bi2O3-Sb2O3-Co3O4-Mn3O4-Nb2O5 at low temperatures. The formation of the pyrochlore phase at temperatures of 700 to 900 degrees C affected the densification kinetics. Pre-calcination of Bi2O3 and Sb2O3 at 550 degrees C successfully reduced the formation of the secondary phase Zn2Bi3Sb3O14 and improved the performance of the ZnO-Bi2O3 varistor by lowering its densification temperature.