Synthesis and Electrical Property Measurements of Ba β-Alumina in a BaO-MgO-Al₂O₃ System

Abstract

An ionic conductor, Ba β-alumina, was synthesized in a BaO-MgO-Al₂O₃ ternary system by solid state sintering at 2023 to 2073K. The Ba β-alumina with a composition of BaO:MgO:Al₂O₃=1:1:5 was in a single phase. Its relative density was 96% of the theoretical density. The electrical conductivity of Ba β-alumina was 4.6×10^-3S⋅m^-1 at 1673K and the activation energy was 126.82kJ⋅mol^-1. The mobile ion could be Ba²⁺, and its ionic transport number was about 0.8 to 0.9 at 1073 to 1673K.