TEXTURE FORMATION IN SUPERCONDUCTING BSCCO-2212/AG COMPOSITE TAPES - EFFECT OF COLD-ROLLING AND LASER FLOAT-ZONE MELTING TECHNIQUE

Bi-2212/Ag composite tapes were fabricated by the doctor blade casting method and then subjected to thermomechanical processing and a laser float zone melting technique, in order to compare the texture developed by these two techniques. The effect of the processing parameters, of the above two different methods, on the texture formation of 2212 phase was monitored by theta-2theta X-ray diffraction patterns, pole-figure studies, and by scanning electron microscopy. Although mechanical deformation yielded a moderate texture, the microstructure of the cold-rolled and solid-state sintered 2212/Ag tape shows the presence of pores and ''weakly linked'' grains. With a laser float zone melting technique, much better texture could be obtained, and it is shown that this texture improves as the scanning rate decreases.