Crystallization of Bi--Sr--Ca--Cu--O glasses in oxygen
- Materials Science Division and Science and Technology Center for Superconductivity, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States) Department of Materials Science and Engineering, Ames Laboratory and Iowa State University, 214 Wilhelm, Ames, Iowa 50011 (United States)
- Materials Science Division and Science and Technology Center for Superconductivity, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)
- Department of Materials Science and Engineering, Ames Laboratory and Iowa State University, 214 Wilhelm, Ames, Iowa 50011 (United States)
A detailed study of the crystallization process for compositions near Bi{sub 2}Sr{sub 2}Ca{sub 1}Cu{sub 2}O{sub {ital y}} was undertaken using differential thermal analysis (DTA), transmission and scanning electron microscopy (TEM and SEM), and x-ray diffraction (XRD). Glasses prepared by a splat-quench technique were free of secondary phases in most cases. A two-step crystallization process in oxygen was observed in which partial crystallization of the glass occurs initially with the nucleation of 2201'' and Cu{sub 2}O, and is completed with the formation of SrO, CaO, and Bi{sub 2}Sr{sub 3{minus}}{sub {ital x}}Ca{sub {ital x}}O{sub {ital y}}. No specific thermal event could be associated with the formation of the 2212'' phase. Rather, formation occurs via conversion of 2201 into 2212. This was a kinetically limited process at temperatures below 800 {degree}C as other phases were found to evolve in addition to the 2212 phase during extended anneals. In contrast, a nearly full conversion to the 2212 phase occurred after only 1 minute of annealing at 800 {degree}C and above. However, changes in resistivity data, secondary phases, and the measured 2212 composition upon extended anneals at 865 {degree}C showed that considerably longer heat treatments were necessary for the sample to reach its equilibrium state.
- DOE Contract Number:
- W-31-109-ENG-38
- OSTI ID:
- 7018718
- Journal Information:
- Journal of Materials Research; (United States), Vol. 7:7; ISSN 0884-2914
- Country of Publication:
- United States
- Language:
- English
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BISMUTH OXIDES
CRYSTALLIZATION
CALCIUM OXIDES
COPPER OXIDES
STRONTIUM OXIDES
ANNEALING
DIFFERENTIAL THERMAL ANALYSIS
ELECTRON MICROSCOPY
GLASS
OXYGEN
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
X-RAY DIFFRACTION
ALKALINE EARTH METAL COMPOUNDS
BISMUTH COMPOUNDS
CALCIUM COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
DIFFRACTION
ELEMENTS
HEAT TREATMENTS
MICROSCOPY
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
SCATTERING
STRONTIUM COMPOUNDS
TEMPERATURE RANGE
THERMAL ANALYSIS
TRANSITION ELEMENT COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies