Thermochemistry of 1 : 2 : 4 phases in the Ho 2O 3–CuO–BaO, Dy 2O 3–CuO–BaO systems

Thermochemical investigations of 1 : 2 : 4 phases in the Ho(Dy)–Ba–Cu–O systems were performed by solution calorimetry in 6 N HCl at 323 K. On the basis of direct dissolution enthalpies of Ho 2O 3, Dy 2O 3, BaCO 3, HoBa 2Cu 4O 8, DyBa 2Cu 4O 8 and CuO thermodynamic data were obtained for the formati...

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Published inThermochimica acta Vol. 315; no. 2; pp. 79 - 85
Main Authors Matskevich, N.I, Popova, T.L, Johansson, L.-J, Berastegui, P
Format Journal Article
LanguageEnglish
Published Elsevier B.V 1998
Subjects
Calorimetry
Quaternary system
Stability
Thermodynamics
Thermodynamics
Stability
Calorimetry
Quaternary system
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Summary:Thermochemical investigations of 1 : 2 : 4 phases in the Ho(Dy)–Ba–Cu–O systems were performed by solution calorimetry in 6 N HCl at 323 K. On the basis of direct dissolution enthalpies of Ho 2O 3, Dy 2O 3, BaCO 3, HoBa 2Cu 4O 8, DyBa 2Cu 4O 8 and CuO thermodynamic data were obtained for the formation of 1 : 2 : 4 phases: 1 – from the oxides; 2 – from the mixture including BaCuO 2; and 3 – from the mixture including BaCO 3. The data obtained showed that the abovementioned phases were thermodynamically stable with respect to the mixture with BaCuO 2, namely, with respect to the reaction: 1/2Ln 2O 3+2CuO+2BaCuO 2+1/4O 2=LnBa 2Cu 4O 8.
ISSN:0040-6031
1872-762X
DOI:10.1016/S0040-6031(98)00245-7