Phase composition, densification and electrical conductivity of La0.9Sr0.1Ga0.8Mg0.2O3-delta consolidated by the two-stage sintering method

Abstract: The influence of the method of sintering on densification, phase assemblage and electrical conductivity of Sr- and Mg-doped lanthanum gallate was investigated aiming to optimize the sintering process of this solid electrolyte. Powder mixtures were prepared by solid state reactions, and the sintering of green compacts was carried out by the two-stage method varying the temperature of the first stage (T-1) and the isothermal temperature (T-2) and time (t(2)) profile. The type and content of predominant impurity phases depend on specific parameters of the sintering process. In the first stage of sintering, the content of impurity phases, such as LaSrGaO4 and La4Ga2O9, decreases with increasing temperature. The relative density of sintered specimens reaches 99% whenever T-1 is 1500 degrees C. The mean grain size varies from 1.45 to 4.9 mu m. At 600 degrees C the electrical conductivity attains 12 mS cm(-1) for T-1 1400 degrees C and T-2 1350 degrees C for 5 h, with activation energy of approximately 1 eV. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Author(s): Reis, SL; Muccillo, ENS

CERAMICS INTERNATIONAL

DOI: 10.1016/j.ceramint.2015.07.061