Performance of GDC with alkali metal carbonates as sintering aids
authors Grilo, JPF; Macedo, DA; Nascimento, RM; Marques, FMB
nationality International
journal SOLID STATE IONICS
author keywords Ceria; Sintering aids; Alkali metal carbonates; Ionic conductivity; N-type conductivity
keywords GRAIN-BOUNDARY CONDUCTIVITY; GADOLINIA-DOPED CERIA; ELECTRICAL-PROPERTIES; ELECTROCHEMICAL PROPERTIES; ELECTRONIC CONDUCTIVITY; TRANSPORT-PROPERTIES; SOLID ELECTROLYTES; OXIDE ADDITION; CERAMICS LN; DENSIFICATION
abstract Gd-doped ceria electrolytes (GDC, 10 at.% Gd) were prepared using a eutectic mixture of Li and Na carbonates as sintering aid (NLC - 0, 1, 3 and 5 mol%), using two processing routes (ceramic and chemical). Structural and microstructural characterization provided no evidence for significant solubility of alkali metal cations in GDC. Materials sintered at 1100 degrees C/4 h were similar in densification ( > 95%) and microstructure to those obtained from a commercial powder sintered at 1500 degrees C/4 h. Impedance spectroscopy in air (200-600 degrees C) and as a function of oxygen partial pressure (from 0.21 to about 10(-25) atm, 600-750 degrees C) showed that the low temperature conductivity of materials prepared using chemical synthesis surpassed the conductivity of a commercial GDC due to higher grain boundary conductivity. The estimated n-type conductivity of materials with NLC was also slightly higher than for pure GDC. The role of sintering aid and processing routes is discussed taking into consideration decomposition and volatilization of alkali salts.
publisher ELSEVIER
issn 0167-2738
year published 2020
volume 346
digital object identifier (doi) 10.1016/j.ssi.2020.115221
web of science category Chemistry, Physical; Physics, Condensed Matter
subject category Chemistry; Physics
unique article identifier WOS:000517851600013
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