Study of improved critical currents and mechanical properties in the Y-Ba-Cu-O superconductor with silver or Y2BaCuO3 or 211 dispersions. Final report, 1 April 1992-31 August 1994
The microstructure of the top-seeded, single grain, melted textured YBCO materials with different vol% 211 were investigated. The homogeneity of 211 distribution was greatly improved by using a solution precipitated 211 powder in preparation. Crack spacings and twin spacings were found to decrease with increasing vol% of the 211 particles. The 211 particles were found to be effective in holding crack propagation. Relationship between twin spacing and interparticle spacing was found to depend on the elastic strain energy from the tetragonal to orthorhombic transformation. The accumulative beneficial effects of the 211 addition on Jc are summarized. The highest Jc was 10(exp 4) A/sq cm at 77K 1T. Transmission electron microscopy of the Au/YBCO interfaces shows well-bonded interfaces with no extraneous phases present with the (001) lattice fringe of YBCO terminated at the interfaces abruptly. Both integral steps of (001) height and multiples of 1/3(001) steps were observed. These finding supports earlier contact resistivity and XPS results of the Au/YBCO interfaces. Amorphous carbon films were shown to protect superconducting YBCO films from degradation by humidity. The YBCO films with carbon coating were founded to retain critical current densities 4 orders of magnitude higher than the uncoated YBCO films after 2h at 100% relative humidity stressing at room temperature.
- Research Organization:
- Columbia Univ., New York, NY (United States)
- OSTI ID:
- 6740296
- Report Number(s):
- AD-A-285609/4/XAB; CNN: F49620-92-J-0160
- Country of Publication:
- United States
- Language:
- English
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ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRACK PROPAGATION
CRITICAL CURRENT
CURRENTS
DOCUMENT TYPES
ELECTRIC CURRENTS
ELEMENTS
HIGH-TC SUPERCONDUCTORS
HUMIDITY
METALS
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
PROGRESS REPORT
SILVER
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES