Decomposition of High Temperature Superconductors in Water

Changes of magnetic susceptibility and electrical resistivity of ceramic superconductors of nominal composition YBa 2 Cu 3 O 7-y and Bi 1.4 Pb 0.6 Sr 2 Ca 2 Cu 3.6 O x observed during their soaking in water are reported. It was found that the YBa 2 Cu 3 O 7-y superconductor is destroyed in few minutes by boiling water. At lower temperatures the hydrolysis reduces the volume of the superconductive phase, as seen from the susceptibility measurements. Reaction of Bi 1.4 Pb 0.6 Sr 2 Ca 2 Cu 3.6 O x with water causes a decrease of the relative volume of both superconducting phases at a rate substantially higher for the high temperature one ( T c = 110 K).