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Low‐Temperature Synthesis and Phase Equilibria in the Y‐Cu‐O Binary System
Author(s) -
Brosha Eric L.,
Garzon Fernando H.,
Raistrick Ian D.,
Davies Peter K.
Publication year - 1994
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.1151-2916.1994.tb05385.x
Subject(s) - copper , ion , binary number , binary system , oxygen , phase diagram , valence (chemistry) , chemistry , thermodynamics , component (thermodynamics) , phase (matter) , inorganic chemistry , analytical chemistry (journal) , organic chemistry , physics , arithmetic , mathematics
The low‐temperature phase relations in the Y‐Cu‐O system were examined using ultrasonically prepared, freeze‐dried nitrate precursors. Under 1 atm of oxygen, Y 2 Cu 2 O 5 was found to be stable above 955 ± 5 K; below this temperature, the component binary oxides CuO and Y 2 O 3 are the only stable phases in the system. The entropy of formation of Y 2 Cu 2 O 5 , with respect to the component oxides, was calculated to be 5.3 ± 2.3 J/(mol.K) at 955 K. Bond valence analyses indicate that the entropy stabilization of this compound is most likely caused by the underbonded character of the copper ions.