A MELT PROCESS TO SUPERCONDUCTIVE FIBERS OF BI2SR2CACU2 OXIDE

particulate precursor of superconductive Bi2Sr2CaCu2 oxide dispersed i n an aqueous poly(vinyl alcohol) solution, was shaped into fibres. The fibres fired at a T-max of 850 degrees C were very porous. Although t hey exhibited a Meissner on-set transition at 85 K, electrical resista nce at 0.02 A cm(-2) at 77 K was still not zero. Exposing the porous f ibres to a temperature slightly above their melting point densified th em. The treated fibres had a sharp Meissner transition and could carry critical current (J(c)) as high as 331 A cm(-2) at 77 K. They were al so more resistant to the effect of a magnetic field than the fibre fir ed at 850 degrees C. Eighty percent of the treated fibre was found to be the superconductive 2 2 1 2 phase.