Aligned bismuth, strontium, calcium cuprate coatings on polycrystalline substrates

An article comprising an oriented thick film superconducting coating on a polycrystalline substrate of MgO, alumina, mullite, SrTiO.sub.3, ZrO.sub.2, ZrTiO.sub.4, BaTiO.sub.3 or mixtures thereof, the coating comprising at least two highly oriented platelet components of

• Bi.sub.a Sr.sub.b Ca.sub.c Cu.sub.d O.sub.x (BSCCO)
• wherein in one component a is 2, b is 2, c is 1, d is 2, and x=8 and, in another components a is 2, b is 2, c is 9, d is 1, and x is .apprxeq.6, oriented such that said BSCCO platelets are essentially parallel to said substrate, said coating having been produced by a process comprising the steps of:
• applying a powdered mixture prepared from Bi.sub.2 O.sub.3, SrCO.sub.3, CaCO.sub.3, and CuO onto a polycrystalline substrate, in amount sufficient to provide, upon melting, a coating of 75 .mu.m to about 250 .mu.m thickness upon said substrate;
• rapidly heating the resultant coated substrate to a temperature ranging from about 1000.degree.-1100.degree. C. for a period of from about 5-30 minutes to completely melt said powder coating and thus form a molten, thick film coating of about 75 .mu.m to about 250 .mu.m thickness;
• rapidly quenching the coated substrate at a rate of at least 50.degree. C./minute to a temperature below about 500.degree. C., which is below that temperature at which phase transition occurs;
• and
• annealing the resultant coated substrate, by heating in an atmosphere of an oxygen-containing gas to a temperature of from about 850.degree.-870.degree. C.