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Sol‐Gel Synthesis of a New Oxide‐Ion Conductor Sr‐ and Mg‐Doped LaGaO 3 Perovskite
Author(s) -
Huang Keqin,
Feng Man,
Goodenough John B.
Publication year - 1996
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/j.1151-2916.1996.tb08554.x
Subject(s) - inorganic chemistry , oxide , differential thermal analysis , thermal decomposition , materials science , perovskite (structure) , chemistry , analytical chemistry (journal) , crystallography , organic chemistry , diffraction , physics , optics
Sr‐ and Mg‐doped LaGaO 3 powders were prepared from a salt acetate solution. The stable solution was peptized by reacting ammonium hydroxide with the precursor solution. Thermal analysis (DTA/TGA) was used to characterize first the dehydration and then the thermal decomposition of the organic ligands of the dried gel. The transformation from amorphous powders into a crystallized, homogeneous oxide phase corresponds to two endothermic peaks in the DTA curve; the first one at 150°C is related to the removal of water and is followed by a shoulder at 250°C. The second peak at 300°C corresponds to a superposition of two decomposition reactions: acetate salt into its oxycarbonate and this oxycarbonate into its oxide. Two subsequent exothermic peaks correspond to oxidation of evolved gases such as methane, hydrogen, and carbon monoxide. TEM observations show an average 10 nm particle size of the LaGaO 3 powder after annealing at 600°C. X‐ray diffraction patterns indicate a pure primitive‐cubic phase is formed by 1300°C without formation of any SrLaGaO 3 impurity. The impedance spectroscopy on a 93%‐dense sample exhibits no grain‐boundary contribution and an ac conductivity σ= 0.11 Ω −1 ·cm −1 at 800°C.