Bulk bars for current lead applications were fabricated from (Bi,Pb)-Sr-Ca-Cu-O (Bi-2223) for low thermal conductivity and high critical current. Bars measuring 17. 8 cm in length were made by uniaxially pressing Bi-2223 powder of controlled (1. 7/0. 34)223 and (1. 8/0. 4)223 phase composition. The bulk bars were densified by subjecting them to a schedule of alternate liquid-phase sintering and cold isostatic pressing. Liquid-phase sintering temperatures were optimized from differential thermal analysis and microstructure morphology. Phase purity and microstructure were evaluated by X-ray diffraction and scanning electron microscopy. Low-resistance silver contacts were applied to the bars by hot-pressing at 820°C and 3 MPa. Critical current densities ≈ 1000 A/cm2 (critical currents of 750 A at 77 K in self-field conditions) were achieved.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering