Some aspects of the thermodynamic behavior of the lead-doped Bi-2223 system.
A thermodynamic assessment of lead-doped Bi-2223 with emphasis on compositions and oxygen partial pressures within the homogeneity region prior to solid-state decomposition is presented. Equations for the variation of oxygen partial pressure with composition and temperature have been derived from our EMF measurements. Long-term metastability was indicated during cycling over a temperature range of {approx} 700-815 C of a lead-doped Bi-2223 sample having an oxygen-deficient stoichiometry of 9.64 prior to solid-state decomposition corresponding to the diphasic CuO---Cu2O system. A trend of increasing negative values of the partial molar enthalpy {Delta}{bar H}(O{sub 2}) and entropy {Delta}{bar S}(O{sub 2})with increasing oxygen deficiency of the condensed phase indicated an increase in ordering of the cuprate structure prior to solid-state decomposition.
- Research Organization:
- Argonne National Laboratory (ANL)
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 937810
- Report Number(s):
- ANL/CMT/JA-20720
- Journal Information:
- Physica C, Journal Name: Physica C Journal Issue: 1-2 ; Apr. 1, 1996 Vol. 260; ISSN 0921-4534; ISSN PHYCE6
- Country of Publication:
- United States
- Language:
- ENGLISH
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