PREPARATION OF BI-PB-SR-CA-CU-O SUPERCONDUCTING THICK-FILMS ON METAL SUBSTRATES OF AU, AG AND NI

Thick superconducting oriented films from samples of nominal composition Bi1.8Pb0.4Sr1.9Ca2.0Cu3.0O(x) were prepared by the method of annealing and cold rolling cycles on Au, Ag, and Ni with silver sublayer substrates with T(c) (zero) = 92, 101, and 99 K respectively. The films obtained consisted of a mixture of 2212 and 2223 phases. The T(c) of these films increased during annealing at an ambient temperature of 830-degrees-C with low P(o2) for up to 200 h. It was shown by emanation thermal analysis that on heating in air, the liquid phase appears in the superconductor at 840-degrees-C and, on contact with silver, at 830-degrees-C. Heating in an argon atmosphere (P(o2) = 5 kPa) reduces these values to 815-degrees-C and 800-degrees-C respectively. No appreciable chemical interaction was noticed. We present the results of an Ag sublayer on Ni thickness calculations, based on diffusion and solubility parameters.