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Phase Stability and Microstructural Evolution in the System Bi 2 Sr 2 CaCu 2 O 8+ x
Author(s) -
Medendorp Nicholas W.,
Gaskell David R.
Publication year - 1999
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.1151-2916.1999.tb02064.x
Subject(s) - partial pressure , analytical chemistry (journal) , oxygen , atmospheric temperature range , thermogravimetric analysis , solidus , differential thermal analysis , high temperature superconductivity , quenching (fluorescence) , phase (matter) , thermal decomposition , decomposition , materials science , mineralogy , chemistry , superconductivity , thermodynamics , fluorescence , diffraction , metallurgy , physics , organic chemistry , alloy , chromatography , quantum mechanics , optics
The dependence of the oxygen nonstoichiometry of Bi 2 Sr 2 CaCu 2 O 8+ x (2212) on temperature and oxygen partial pressure has been determined in the temperature range of 300° to 1000°C and the oxygen partial pressure range of 3 × 10 −3 to 1 atm (1 atm = 10 5 Pa). The solidus temperature of 2212 was identified by differential thermal analysis over the same ranges of temperature and oxygen partial pressure. The nature of the decomposition of 2212 was determined by thermogravimetric analysis in the temperature range of 800° to 1000°C and oxygen partial pressure range of 3 × 10 −3 to 1 atm. Microstructural evolution was examined by quenching materials, equilibrated with atmospheres of fixed partial pressures of oxygen, at various stages in the decomposition and identifying the phases present by electron microscopy and wavelength dispersive spectroscopy. With increasing temperature, at fixed oxygen partial pressure, the decomposition of 2212 in the presence of 1.9 mol% Sr 0.4 Ca 0.6 CuO 2 follows the sequence 2212 + Sr 0.4 Ca 0.6 CuO 2 → 2212 + Sr 0.4 Ca 0.6 CuO 2 + Sr 0.2 Ca 1.8 CuO 3 → Sr 0.5 Ca 0.5 CuO 2 + Sr 0.3 Ca 1.7 CuO 3 + Sr 0.5 Ca 0.5 Cu 2 O 3 + L 1 → Sr 0.5 Ca 0.5 CuO 2 + Sr 0.3 Ca 1.7 CuO 3 + L 2 → L 3 .