The Bi-2223 Superconducting Wires With 200A-Class Critical Current

Abstract

Critical current of a silver-sheathed Bi-2223 tape using controlled-overpressure sintering has attained 201 A, which is equivalent to 493 A per 10 mm-width. The engineering current density is 21kA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , while the critical current density on the total filaments area is 56 . Critical currents are also improved noticeably at low temperatures and high magnetic fields normal to the tape plane. Typical critical currents have reached 500 A at 4.2 K in 5 T and 200 A at 20 K in 10 T. The highest critical currents of long wires currently have reached 195 A for 70 m and 191 A for 178 m. The wires with 200 A-class critical current are similar in mechanical properties to 150 A-class long wires commercially produced by Sumitomo Electric using the controlled-overpressure sintering. The microstructure study has predicted far higher potential of critical current, according to the confirmed remaining issues on the 200 A-class tapes; incomplete orientation order, aggregation of alkaline earth cuprates and inter-granular Bi-2212.