Conveners
M2Or1A - BSCCO - Conductors
- Timothy Haugan (U.S. Air Force Research Laboratory)
- Eric Hellstrom (ASC/NHMFL - Florida State University)
Bi-2212 is a round-wire, high temperature superconductor that develops high Jc for high-field magnets when it is overpressure (OP) processed. Recent advances in Bi-2212 powder, wire fabrication, and OP heat treatment have improved the performance of the Bi-2212 wire. We are designing, winding, OP heat treating, and characterizing the performance of Bi-2212 coils and comparing their measured...
Significant increases in the current-carrying capacity (Ic) of Ag-sheathed Bi-2212 over the past several years has made this material a viable candidate for high-field magnets. However, the management of Ic degradation as a function of applied strain remains a challenge, as does the implementation of overpressure processing (OP) heat-treatment conditions for magnets. In this study, we...
Bi2Sr2CaCu2Ox (Bi-2212) is the only high temperature superconductor (HTS) available in the round wire form preferred by magnet builders. Recent advances in the processing have raised its critical current density (Jc) > 6500 A/mm2 at 4.2 K and 15 T, placing Bi-2212 at the forefront of candidates for future HTS high field magnets. The key microstructure for high Jc is a unique a-axis grown...
Achieving high Jc in Bi2Sr2CaCu2Ox (Bi-2212) round wire requires overpressure heat treatment (OPHT) to eliminate current-limiting bubbles. The OPHT has a maximum temperature of ~890 °C and is done with 50 bar overpressure with 1 bar oxygen partial pressure (PO2). During OPHT, the diameter of the Bi-2212 wire shrinks about 4%, with about 80% of this densification occurring during a 2 h hold at...
It is well known from designs analysis and data, that much lighter weight, higher power density and more efficient motors and generators will be enabled by HTS provided it is developed in suitable forms, preferably operating at or above 40 K. Although DC rotors can be wound with HTS tapes, for example 2G, to generate the required 3 to 5 T fields, stators operate in AC mode albeit at lower...