Effects of silver and lead on the phase stability of Bi[sub 2]Sr[sub 2]Ca[sub 1]Cu[sub 2]O[sub 8+x] and Bi[sub 2]Sr[sub 2]Ca[sub 2]Cu[sub 3]O[sub 10+x] above and below the solidus temperature

Journal Article · Thu Sep 01 04:00:00 EDT 1994 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1994.tb04598.x· OSTI ID:6933632

MacManus-Driscoll, J L; Bravman, J C ^[1]; Savoy, R J; Gorman, G; Beyers, R B ^[2]

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1. Stanford Univ., CA (United States). Dept. of Materials Science and Engineering
2. IBM Almaden Research Center, San Jose, CA (United States)

A solid-state ionic technique has been used to determine the effects of Ag on the phase stability of Bi[sub 2]Sr[sub 2]Ca[sub 1]Cu[sub 2]O[sub 8+x] (Bi-2212), and Ag and Pb on the phase stability of Bi[sub 2]Sr[sub 2]Ca[sub 2]Cu[sub 3]O[sub 10+x] (Bi-2223), over a temperature range of 600 to 910 C and oxygen partial pressure range of 10[sup [minus]6] to 10[sup 0] atm (10[sup [minus]1] to 10[sup 5] Pa). The addition of Ag to Bi-2212 leads to a marginal decrease in the stability of the phase above 883 [+-] 3 C and 7 [times] 10[sup [minus]2] atm (7 kPa) oxygen, resulting in a reduction in the incongruent melting point by 15 C in air. The substitution of Pb for Bi in the (Bi,Pb)-2223 phase leads to an increase in phase stability below the solidus, but to only a minor change in stability above the solidus. For both phases, several incongruent melting reactions have been identified over the range of reduced oxygen partial pressures studies. In addition, the phase equilibria both above and below the stability line have been determined for certain regions of the stability diagrams. From the thermodynamic information obtained in this study an improved melt-processing route for Bi-2212 has been found which minimizes unwanted phases. In addition, the optimum precursors for the formation of more phase-pure (Bi,Pb)-2223 during shorter time periods have been found by determining the initial decomposition products of (Bi,Pb)-2223, both above and below the solidus.

• OSTI ID: 6933632
• Journal Information: Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 77:9; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ALKALINE EARTH METAL COMPOUNDS
BISMUTH COMPOUNDS
BISMUTH OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
DATA
DIAGRAMS
ELEMENTS
EXPERIMENTAL DATA
HIGH-TC SUPERCONDUCTORS
INFORMATION
LEAD
METALLURGICAL EFFECTS
METALS
MICROSTRUCTURE
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHASE DIAGRAMS
PHASE STUDIES
SILVER
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS