We report on the synthesis of varistor ceramics from pre-reacted varistor phases, namely the ZnO phase, the Bi2O3-phase and the Zn7Sb2O12 spinel phase, by high-energy milling of the starting mixture and sintering. Detailed microstructural analysis and the analysis of the varistor dopants showed that intensive milling strongly influences their distribution and the homogeneity of the composition. It also enhances the nucleation of inversion boundaries, which strongly affects grain-growth and microstructure homogeneity, and therefore also the current-voltage characteristics of varistor ceramics.
COBISS.SI-ID: 20935719
The inversion-boundary-induced grain-growth mechanism in ZnO ceramics and influence of amount of IBs-triggering dopant on growth mechanism, growth kinetics and microstructure development in ZnO ceramics doped with Sb2O3 are reported. Understanding these processes enabled us to prepare coarse-grained Sb2O3 doped ZnO ceramic. Microstructure development in ZnO ceramics doped with very low amounts of Bi2O3 and Sb2O3 revealed main elements that influence IBs-induced grain-growth mechanism in basic ZnO-Bi2O3-Sb2O3 system of varistor ceramic, which is essential for tailoring its microstructure.
COBISS.SI-ID: 675498