Measurement and Properties of the Oxide Ionic Conductivity of β- and δ-Phases in the Binary (Bi₂O₃)_1−x(Tb₄O₇)_x System

Abstract

The total conductivity (σ_T) in the β-phase and δ-Bi₂O₃ doped with Tb₄O₇ system was measured in the composition range between 1 and 30 mol% Tb₄O₇ at different temperatures. According to the DTA/TG results, this tetragonal type solid solution was stable up to about ∼740°C, and the solubility limit was found at ∼5 mol% Tb₄O₇ in the β-phase; this fcc type solid solution was stable up to about ∼740°C, and the solubility limit was found at ∼30 mol% Tb₄O₇ in the δ-phase. All phases showed predominant oxide ionic conduction. It has been proposed that β- and δ-Bi₂O₃ phases contain a large number of oxide anion vacancies and incorporated terbium cations at tetrahedral sites that affect the oxygen sublattice of the crystal structure.

Keywords:

• bismuth oxide
• oxygen ionic conductivity
• terbium oxide

Acknowledgments

This work was supported by Erciyes University (EUBAP).