In-situ high-temperature study of Bi,Pb(2223) phase formation and stability inside Ag-sheathed tapes

In-situ diffraction techniques proved to be very powerful for the understanding of the reactions occurring inside Ag-sheathed Bi,Pb(2223) tapes. By means of in-situ high-temperature neutron diffraction on monofilamentary tapes, the amount of secondary cuprates was quantitatively estimated and the role of them during the reaction thermal treatment was elucidated. For the first time, a direct evidence of a partial melting occurring prior to forming the Bi,Pb(2223) was observed as a decrease of the total amount of crystalline matter in the sample and the amount of the transient liquid and the amorphous matter was quantified. Furthermore, evidence of Bi,Pb(2223) stability on cooling was observed, being the re-growth of Bi(2212) on cooling not related to any decomposition of Bi,Pb(2223). High-temperature linear expansion coefficients of Bi,Pb(2223) were measured. Preliminary results of recently performed in-situ synchrotron X-ray diffraction complete this work.