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Influence of the Oxide Precursors on the Reaction Sequencing and Kinetics in the Yttrium—Barium—Copper—Oxygen System
Author(s) -
Licci Francesca G.,
Wang Longmei,
Besagni Tullo
Publication year - 1997
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.1151-2916.1997.tb03057.x
Subject(s) - barium , yttrium , stoichiometry , ternary operation , barium oxide , thermal stability , kinetics , copper , reagent , inorganic chemistry , yttrium barium copper oxide , oxygen , oxide , chemistry , materials science , high temperature superconductivity , metallurgy , superconductivity , physics , organic chemistry , quantum mechanics , computer science , programming language
The reactions of stoichiometric Y 2 O 3 , CuO, and different barium salts (BaCO 3 , Ba(NO 3 ) 2 , BaO 2 , BaCuO 2 ) for forming various compounds in the yttrium—barium—copper—oxygen system (i.e., YBa 2 Cu 3 O 7–8 , BaCuO 2 , Y 2 BaCuO 5 , and Y 2 Cu 2 O 5 ) were systematically investigated by thermal analysis and X‐ray diffractometry. In a few cases, the relevant activation energies were calculated. The reaction pathway and kinetics were significantly dependent on the physicochemical and thermal stability of the barium precursors, as well as on the crystalline size of the reagent. Binary BaO‐CuO phases formed at low temperature (650°‐700°3C) when in the presence of easy‐to‐decompose barium precursors, and then slowly transformed to ternary compounds; in contrast, when barium ions were released at temperatures of >900°3C, ternary phases formed directly from the components.