Macro-thermogravimetrical investigations of the O-2 exchange during phase formation in BSCCO(2223) tapes with Ag, AgMg, AgAu sheaths or SrCO3 or SrZrO3 barriers

Oxygen exchange of BSCCO with the annealing atmosphere through the tape she ath plays no important role in the formation of BSCCO during the reaction h eat treatment, Change of the oxygen support is expected to be responsible f or reduced superconducting performance of conductors with alloyed shaeth ma terials or modified configurations as BSCCO tapes with AgMg and AgAu sheath s as well as with interfilamentary resistive barriers (AC conductors). In t hose tapes the change in oxygen content was montiored during the first heat treatment by means of a macro-thermogravimetrical method suitable for long sample lengths, The main result is that highly alloyed AgMg sheaths and es pecially barrier tapes hinder significantly the oxygen diffusion during BSC CO(2223) formation. A correlation with the BSCCO phase evolution and the ac hieved transport currents was tried.