Overpressure processing Bi2223/Ag tapes

We report on the effect of overpressure processing on the electromagnetic p roperties and microstructure of monocore and multifilamentary Bi2223/Ag tap es. Samples at various stages of the usual thermo-mechanical processing for Bi2223/Ag tapes (from as-rolled to fully processed) were subjected to anne aling at 815-820 degreesC for 18-108 h in a static Ar + O-2 atmosphere at t he overall pressure 17.5 +/- 0.5 MPa (pO(2) = 0.003-0.02 MPa), Density meas urements, microhardness tests, and SEM examination of polished sections rev eal a notable densification of overpressure-processed samples. For partly r eacted (so called HT1) samples, we found that overpressure processing for 3 6 h is sufficient to densify the Bi2223 core from 70 +/- 5 to 87 +/- 4% the oretical density and increase self-field J(c)(77K) from 8 +/- 1 to 30 +/- 5 kA/cm(2) The results show that onestep processing of Bi2223/Ag tapes is po ssible.