DI-BSCCO wires by Controlled over pressure sintering

Abstract

Sumitomo Electric successfully developed drastically innovative Bi-2223 (DIBSCCO), namely, commercially produced Bi2223 long length wires using the controlled over pressure sintering (CT-OP) with unique properties quite different from conventional silver sheathed BSCCO wires. CT-OP prevented pores occurring in BSCCO cores, so it reformed conventional Bi2223 wires to DI-BSCCO with excellent properties of higher critical currents, stronger mechanical strength and better durability against temperature rise in cryogen such as pressurized liquid nitrogen. It enhanced the critical current by 50 percent conventional wires sintered in normal atmospheres. Critical tensile stress was also improved by more than 150 percent. Any ballooning defects and degradation of critical current, one of the critical problems for the conventional BSCCO wires, were not found in full length of several km long DI-BSCCO tapes after 24 hours immersion into 1MPa liquid nitrogen.