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Effect of A‐site ion nonstoichiometry on the chemical stability and electric conductivity of strontium and magnesium‐doped lanthanum gallate
Author(s) -
Ishii Kento,
Matsunaga Chika,
Munakata Fumio,
Uchikoshi Tetsuo
Publication year - 2020
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.16767
Subject(s) - gallate , lanthanum , electrical resistivity and conductivity , materials science , strontium , conductivity , analytical chemistry (journal) , ion , reactivity (psychology) , doping , inorganic chemistry , chemistry , nuclear chemistry , medicine , alternative medicine , optoelectronics , organic chemistry , chromatography , pathology , electrical engineering , engineering
A series of Sr‐ion deficient perovskites La 0.8 Sr 0.2− x Ga 0.8 Mg 0.2 O 2.8− δ (LSGM8282, x = 0.00, 0.05, 0.10, 0.15, 0.20), was synthesized by a conventional solid‐state reaction method and their electric conductivity and chemical reactivity with Gd‐doped ceria were investigated. Reactivity tests between the LSGMs and Ce 0.9 Gd 0.1 O 2− δ (GDC) were carried out by X‐ray diffraction, SEM‐EDS, and electric conductivity measurements. The Sr‐ion deficient LSGMs have a lower reactivity against the formation of high‐resistivity phases than the stoichiometric ( x = 0.00) LSGM. The reaction layer formed at the interface of LSGM and GDC during the sintering process due to the mutual diffusion of the cations was classified into five layers depending on the composition. The introduction of the Sr‐ion deficient LSGM suppressed the formation of the highly resistive Sr‐rich (La 1+ x Sr 1− x )Ga 3 O 7− δ phase. It was suggested that the Sr‐ion deficient LSGM (La 0.8 Sr 0.2− x Ga 0.8 Mg 0.2 O 2.8− δ ) of x = 0.15 was the best composition for suppressing the reaction with the GDC interlayer while retaining a relatively good electric conductivity.