High-temperature superconducting polymer-ceramic compositions

Polymer-ceramic compositions, formed from polymeric binders (super high mol ecular polyethylene, polymethylmethacrylate) and superconducting ceramics ( Y1Ba2Cu3O7-chi), were obtained by hot-pressing at 200 degreesC possessing 9 6 and 94 K transition critical temperature, respectively. Superconductivity of the composition is reduced as the ceramic's grain surface oxygen partic ipates in thermo-oxidation destruction reaction with the binder. Thermal tr eatment at alpha -transition temperatures and in oxygen environment restore s the superconducting properties of the composition. To sustain superconduc tivity of the composition immediately after the hot-pressing, i.e. eliminat ing the stage of restoration, very small quantities, about 1% of the binder 's weight, of antioxidant organic compound has to be added in the initial m ixture of polymer and ceramic. By the polymerization of merhylmethacrylate of the separate pre-pressed specimens of ceramic, Y1Ba2Cu3O7-chi - polymeth ylmethacrylate compositions were obtained. It was shown that the compositio ns obtained using the polymerization method maintained their superconductin g properties. Anomalous impact of Y1Ba2Cu3O7-chi oxide ceramic on the kinet ics of the initiated polymerization of methylmethacrylate by dinitrylazoiso oleic acid was observed. (C) 2001 Published by Elsevier Science B.V.