Corrosion of superconductors-especially of YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// cuprate

Electronic properties of superconductors deteriorate with time by oxidation or other chemical attack enforced by thermal cycling. Despite being oxides, cuprate superconductors deteriorate in lab atmosphere. The corrosion of, e.g., YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// (YBCO) is mainly caused by H/sub 2/O and CO/sub 2/, which react to Ba-hydroxide and to Ba-carbonate. As reaction paths the CuO-chain-BaO-layers are the fastest ones, whereas the out-of-plane paths are slower. Grain and twin boundaries or strain have been identified as paths for O-diffusion or reaction with H/sub 2/O and CO/sub 2/.