THE DEGRADATION BEHAVIOR OF HIGH-TC BSCCO/AG SUPERCONDUCTING MICROCOMPOSITES IN WATER

Bi(Pb)-Sr-Ca-Cu-O/Ag (BSCCO/Ag) superconducting microcomposites with zero-resistance temperatures from 102 to 108 K and critical current densities of 300-600 A/cm2 at 77 K were produced by oxidation and annealing of metallic precursor alloys. The reaction of BSCCO/Ag specimens with water and the degradation on their superconducting properties were studied by mass loss measurement, electrical transport measurement, microstructural observation and microanalysis. Although there is a general tendency toward a decrease in the critical current density after a long time exposure in water, the specimens containing high Ag (almost-equal-to 80 wt.%) showed very little change in T(c) and J(c) up to 104 days of immersion in water. It was found that the superconducting 2-2-2-3 phase is stable in water, but some non-superconducting Ca-rich oxides dissolve and damage the connection between the superconducting grains in the low-Ag containing specimens. The excellent water resistance in the high-Ag containing BSCCO/Ag superconducting microcomposites provides an important advantage for industrial applications.