Hot isostatic pressure reaction treatment of Ag-sheathed Bi,Pb(2223) tapes

One of the parameters of power in tube (PIT) processed Bi,Pb(2223) tapes which still leaves room for improvement is the density of the filaments, presently reported to be around 80–90%. To some extent this can be addressed with optimised intermediate deformation methods, such as periodic pressing, but this solution is limited by the necessity to heal the damage after deformation. The synthesis of the Bi,Pb(2223) phase whilst applying a hot isostatic pressure (HIP) has been found to be an attractive alternative route to obtain higher ceramic density. In this work we compare the properties of tapes processed under various isostatic pressure up to 1000 bar. High pressure was found to fasten the kinetics of phase formation. SEM observation showed an increased density of the ceramic core in HIP processed tapes. 20 h annealing under 100 bar improved the critical current density by 30% compared to the standard first heat treatment in PIT process.