Bi,Pb(2212) and Bi(2223) formation in the Bi-Pb-Sr-Ca-Cu-O system

A new route has been found for producing the Bi2Sr2CaCu2Oy, phase with Pb substituted for part of the Bi (denoted Bi,Pb(2212)). By this novel route, Bi,Pb(2212) has been prepared in air at 860 degrees C. For comparison, this phase has also been prepared in argon at 740 degrees C by the previously known route. Bi,Pb(2212) transforms from a tetragonal to an orthorhombic structure as the Pb content grows. Once this phase was obtained with a nominal composition of Bi2-xPbxSr2CaCu2Oy, with Pb contents x=0, 0.2, 0.4 and 0.6, the Bi(2223) phase was formed starting from Bi(2212) and Bi,Pb(2212). Single-phase samples were obtained after two heat treatments at 849 degrees C with Bi,Pb(2212) and a proportion of Pb of x=0.4. This proportion corresponds to the one used previously by the authors to obtain high critical current carrying tapes in Ag-clad Bi(2223) tapes