Reactive sintering for oriented and connected Bi-2223 superconductive oxides from a mixture of delaminated Bi-2212 and fine powdered supplemental ingredients

For the purpose of obtaining high critical current densities (J_c), well-oriented and connected Bi-2223 was prepared by improved processing techniques, i.e., (i) delamination by mild, wet grinding of a mixture of Bi-2212 and a supplemental phase containing Pb, Sr, Ca and Cu; (ii) preparation of green sheets by casting the slurry on a thin silver plate using an applicator bar; (iii) compression of the green sheet and calcination at 800°C in air; and (iv) firing at 827°C in 7% O₂-Ar gas flow. Holding samples under compression in each processing step after delamination promoted grain growth, degree of orientation, fraction of Bi-2223 and, accordingly, better connectivity of the grain colonies.