Composite reaction texturing of Bi-based 2212 compound

Textured Bi/sub 2/Sr/sub 2/Ca/sub 1/Cu/sub 2/O/sub 8+x/ (2212) conductors have been fabricated by a method termed composite reaction texturing (CRT), which makes use of inert whiskers or fibers to align superconducting grains and control their morphology. The process has two stages: the initial alignment of fiber material in a precursor, followed by a composite reaction stage to develop a textured ceramic microstructure. Two different methods of achieving this fiber alignment are compared. Disc-shaped pellets of 2212 with random MgO whisker alignment in the pellet plane are compared with polymer processed material with unidirectional whisker alignment. Although the resulting textures are strikingly different, the transport current densities are high for both materials. Samples with dimensions up to 200 mm*100 mm*2 mm have been fabricated, and the method clearly has promise for the production by wind-and-react or form-and-react techniques of high critical current conductors with large cross-sections as well as complex shapes.<
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