Analysis of crystal phases of Na+-β/β-alumina/YSZ composite prepared by vapor-phase synthesis from YSZ-toughened α-alumina

Crystal phases of Na+-beta/beta ''-alumina electrolytes prepared by vapor-phase synthesis to resolve problems associated with solid-state reaction (i.e., Na2O loss at high sintering temperature and limitation to reducing the thickness) were analyzed. Na+-beta/beta ''-alumina/YSZ composite was prepared by alpha- to beta/beta ''-alumina phase conversion using sodium aluminate (i.e. Na2O source) from a alpha-alumina/YSZ sintered sample by vapor-phase synthesis. A fabricated Na+-beta/beta ''-alumina fully crystalized without any secondary phase. Its bulk density increased with increasing YSZ content. A maximum ionic conductivity of 1.8 x 10(-2) S/cm at 350 degrees C was obtained from a 50 wt.% YSZ-added specimen converted at 1500 degrees C for four hours. (C) 2019 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.