Coated-wire in-tube processing of silver/BISMUTH-2223 superconductors.
The advantage of coated-wire-in-tube (CWIT) processing is based on evidence that a thin (2-5 µm) layer at the silver/superconductor interface carries most of the current in silver-sheathed Bi-2223 tapes. In CWIT processing, fine silver wires (75-125 µm diameter) are coated with Bi-2223 precursor powder (coating thickness ~25-100µm), then loaded into a silver tube and processed as in conventional powder-in-tube processing. This increases the silver/superconductor interface area by factors of ~10 relative to monofilament and ~3 relative to multifilament. Because the silver is added as wires, not as particles or whiskers, it provides a continuous substrate on which Bi-2223 grains can align themselves. As a result, Jc increases monotonically with the silver/superconductor interface area per unit superconductor area when the well-aligned regions remain continuous along the length of the conductor. The results are consistent with evidence that the superconducting properties of material at the silver/superconductor interface are superior to those of material at the core interior, and demonstrate that increasing the silver/superconductor interface area may enhance tape performance.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL
- Sponsoring Organization:
- DOE
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 8879
- Report Number(s):
- ANL/ET/CP-94780; ON: DE00008879
- Country of Publication:
- United States
- Language:
- English
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