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Reaction Sequencing During Processing of the 123 Superconductor
Author(s) -
Thomson William J.,
Wang Hong,
Parkman David B.,
Li Dong X.,
Strasik Michael,
Luhman Thomas S.,
Han Chan,
Aksay Ilhan A.
Publication year - 1989
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.1151-2916.1989.tb06011.x
Subject(s) - tetragonal crystal system , decomposition , phase (matter) , superconductivity , helium , materials science , microstructure , mineralogy , crystallography , chemistry , physics , condensed matter physics , organic chemistry
Reaction sequencing studies were conducted for two precursors to the 123 superconductor in air and helium environments. In air, the reactants in both precursor systems produce an intermediate 123 phase at 1000 K without going through the BaCuO 2 and Y 2 BaCuO 5 intermediate phases, observed in earlier work with mixed powder precursors. In helium, the fully developed 123 tetragonal phase is formed at temperatures as low as 880 K, but it also decomposes to Y 2 BaCuO 5 , BaCu 2 O 2 , and BaCuO 2 ; the extent of decomposition depends on the temperature. The 123 tetragonal phase completely decomposes by 1075 K, but it can be reformed if the atmosphere is switched back to air at a temperature above 950 K.