Fabrication of cold-rolled Ag-sheathed Bi(2223) tapes by a partial-melting process

The extensive work presented here reports a new method to fabrication of Bi-2223/Ag tapes by a partial-melting process in order to achieve good grain alignment and connection. This partial-melting process consists of three heating cycle. The green tapes require a first heat treatment at relative lower temperature in order to ensure 2212 phase form sufficiently and prevent 2223 phase from formation. A short period of melt treatment at 860 degrees C for 15 minutes is applied at the second annealing. The pre-oriented 2212 phase transform to the highly-aligned 2223 phase by sintering at 835 degrees for 200h during the third heating cycle. The improvement of grain size and texture compared with the normally processed tapes has been achieved by this partial-melting process.