Synthesis and characterization of high temperature superconductor materials
Abstract
High temperature superconductors are oxides and, therefore, inherently brittle. A process involving thermal decomposition of silver nitrate in the presence of YBa2Cu307 (123) powder was developed which shows promise for synthesis of fine diameter wires. The silver deposits uniformly on the 123 powder as indicated by optical and scanning electron microscopy. The composite powder can be formed into rods via drawing and swaging through conical converging dies. Finer diameter wires were produced by slurry extrusion of the composite powder in a polymeric vehicle. The current carrying capacity, Jc, continues to rise due to better understanding of the Ag/superconductor interface. Jc values of a typical wire has now reached 400 A/sq cm at 77 K and zero magnetic field, with a superconducting transition temperature of 93 K. In addition, the AgN03 decomposition process can be employed with fine HTS powder and ethylene glycol as a suitable vehicle to produce an adherent, stable high temperature superconducting paint. The composition, chemistry, and uniformity of dispersion of Ag was investigated by x ray diffraction, x ray photoelectron spectroscopy, and scanning electron microscopy.
- Publication:
-
In AGARD
- Pub Date:
- October 1990
- Bibcode:
- 1990asta.agar.....F
- Keywords:
-
- Brittleness;
- Chemical Composition;
- Decomposition;
- High Temperature Superconductors;
- Superconductivity;
- Thermal Decomposition;
- Wire;
- Electron Microscopy;
- Ethylene Compounds;
- Glycols;
- Magnetic Fields;
- Optical Scanners;
- Oxides;
- Photoelectron Spectroscopy;
- Silver Nitrates;
- X Ray Diffraction;
- X Ray Spectroscopy;
- Solid-State Physics