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Low‐Temperature Hydrothermal Synthesis of Phase‐Pure (Ba,Sr)TiO 3 Perovskite using EDTA
Author(s) -
Gersten Bonnie L.,
Lencka Malgorzata M.,
Riman Richard E.
Publication year - 2004
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.1151-2916.2004.tb06355.x
Subject(s) - ethylenediaminetetraacetic acid , hydrothermal circulation , strontium , phase (matter) , solid solution , chemical stability , barium , materials science , hydrothermal synthesis , perovskite (structure) , atmospheric temperature range , inorganic chemistry , chemistry , mineralogy , analytical chemistry (journal) , nuclear chemistry , chemical engineering , chelation , thermodynamics , crystallography , metallurgy , chromatography , physics , organic chemistry , engineering
A thermodynamic model was developed to describe the stability of (Ba,Sr)TiO 3 (BST) solid solutions in the Ba–Sr–Ti–K–(EDTA)–H 2 O (EDTA = ethylenediaminetetraacetic acid) system. Phase diagrams were computed to identify the range of conditions suitable for making phase‐pure BST. Hydrothermal experiments were performed to validate the thermodynamic model. The model was found to be more useful when an ideal solid solution was used to estimate the energetics for the BST phase instead of experimental thermodynamic data. In addition, EDTA was found to promote stable conditions for BST formation. When attempting to prepare Ba 0.50 Sr 0.50 TiO 3 without EDTA, BaTiO 3 ‐rich and SrTiO 3 ‐rich phases precipitated separately, at 70°–160°C. However, in the presence of EDTA, a phase‐pure Ba 0.55 Sr 0.45 TiO 3 solid solution was obtained at 90°–120°C. EDTA is effective because it prevents phase heterogeneities from forming and equalizes the adsorption affinity of strontium and barium species.