Large current high T/sub c/ superconducting rods for current lead applications

The high critical temperature and low thermal conductivity of ceramic superconductors make them suitable for current leads in low T/sub c/ magnets. The plastic extrusion process was applied for the fabrication of YBaCuO and BiSrCaCuO rods for this application. The platelet morphology of BiSrCaCuO was utilized to process rods with a high degree of preferred orientation, through a combination of plastic extrusion and cold isostatic pressing. Rods with consistent current capacities of few hundred amperes over 15 cm have been fabricated. The critical currents of these rods were measured at various temperatures and magnetic fields. Other related aspects such as contact resistance, mechanical properties and degradation due to thermal cycling have also been evaluated.<>