STRUCTURAL STUDIES OF BSCCO AG-TAPES BY HIGH-ENERGY SYNCHROTRON X-RAY-DIFFRACTION/

High-energy (100 keV) synchrotron X-ray diffraction has been identifie d as a powerful tool for characterizing texture and structural phases, within Ag clad high T-c, superconducting tapes of the (Bi,Pb)-Sr-Ca-Cu -O (BSSCO) type during synthesis of (Bi,Pb)(2)Sr2Ca2Cu3Ox (Bi-2223) fr om (Bi,Pb)(2)Sr2CaCu2Ox (Bi-2212). Using a CCD camera, the texture and concentration of the dominant structural phases can be determined sim ultaneously within fractions of minutes. As an example, we report on t he in situ annealing behavior in air at 835 degrees C of an as-rolled monofilament tape. It is shown that the alignment of the superconducti ng grains takes place almost exclusively in the Bi-2212 phase. During heating, the texture profile narrows rapidly above 750 degrees C, coin cident with the dissolution of (Ca,Sr)(2)PbO4. A 98% conversion of Bi- 2212 is obtained within 19 h, but furnace cooling leads to the formati on of secondary phases such as Bi-2201 and (Ca,Sr)(2)PbO4. Room temper ature data on similar tapes show that subsequent deformation and annea ling results in a higher Bi-2223 phase purity while slightly deteriora ting the grain alignment. (C) 1998 Elsevier Science B.V.