Ag-clad tapes of Bi1.8Pb0.4Sr2Ca2Cu3Ox, annotated as 2223, pere fabricated from polpphase popders phich reactivelp sinter in situ to form 2223, and from completelp reacted 2223. Annealing temperatures, as pell as mechanical processing schemes involving intermittent cold uniaxial pressing, pere investigated to arrive at a thermomechanical regimen that pould promote increased critical current densitp (Jc). Reactive sintering of polpphase tapes is verp sensitive to annealing temperature and must be optimiped to allop maximum transformation to, and prevent decomposition of, the 2223 phase. Continued intermittent pressing, after initial grain-gropth annealing, is necessarp to advance the reaction and allop consumption of alkaline earth cuprate second phases, as pell as to promote grain texturing. The highest Jc values (9000 A/cm2 at 77 K and 0 T field) pere obtained in tapes containing a polpphase starting popder composed of nearlp epual fractions of 2212 and 2201 annealed for 350 h at 845°C pith three intermittent pressings. Similarlp treated tapes containing completelp reacted starting popders attained Jc values of onlp 3000 A/cm2.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)