Development of high Tc (greater than 110K) Bi, Tl and Y-based materials as superconducting circuit elements. Annual Report, 7 Mar. 1990 - 21 Feb. 1991
This report is presented in two parts. Part 1 deals primarily with Bi-based materials and a small amount of work on a Y-based composition while Part 2 covers work on Tl-based materials. In Part 1, a reliable and reproducible process for producing bulk bismuth-based superconductors has been developed. It is noted however, that a percentage of the tapecast material experiences curling and fracturing after a 30 hour sintering period and is thus in need of further examination. The Bi-Sr-Ca-Cu-O (BSCCO) material has been characterized by critical temperature data, X-ray diffraction data, and surface morphology. In the case of T sub c, it is not critical to anneal the material. It appears that the BSCCO material has the possibility of producing a better grounding strap than that of the 123 material. Attempts to reproduce near room temperature superconductors in the Y-Ba-Cu-O system were unsuccessful. In Part 2, several methods of processing the high temperature superconductor Tl2Ba2Ca2Cu3O10 were investigated; i.e., different precursor compositions were sintered at various sintering times and temperatures. The highest superconductig temperature was found to be 117.8K when fired at 900 C for three hours. Higher sintering temperatures produced a melted sample which was nonsuperconducting at liquid nitrogen temperature. Also, a preliminary study found Li2O substitutions for copper appeared to increase the transition temperature and create fluxing action upon sintering. It was suggested that lower sintering temperatures might be obtained with lithium additions to produce reliable Tl2Ba2Ca2Cu3O10 processing methods.
- Research Organization:
- Clemson Univ., SC (United States)
- OSTI ID:
- 5341040
- Report Number(s):
- N-91-26948; NASA-CR-188581; NAS-1.26:188581; CNN: NAG1-1108
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HIGH-TC SUPERCONDUCTORS
CRITICAL TEMPERATURE
FABRICATION
BISMUTH OXIDES
CALCIUM OXIDES
COPPER OXIDES
CURRENT DENSITY
LITHIUM OXIDES
MORPHOLOGY
SINTERING
STRONTIUM OXIDES
TEMPERATURE EFFECTS
THALLIUM OXIDES
YTTRIUM OXIDES
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
BISMUTH COMPOUNDS
CALCIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
LITHIUM COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
STRONTIUM COMPOUNDS
SUPERCONDUCTORS
THALLIUM COMPOUNDS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
YTTRIUM COMPOUNDS
360603* - Materials- Properties