SUPERCONDUCTIVE YBA2CU3O7-X FIBERS FROM AN EXTRUDABLE DISPERSION OF APARTICULATE PRECURSOR

A particulate precursor of YBa2Cu3O7-x was dispersed in a concentrated acetic/formic acid solution of yttrium, barium and copper acetates to form an extensible, viscous mixture. This dispersion was stable, unli ke one prepared from superconductive YBa2Cu3O7-x itself. Fibres extrud ed from the viscous dispersion were fired at 935 degrees C in the pres ence of oxygen. Although the fired fibres were not fully densified, th ey had a sharp Meissner transition temperature at 90 K and an apparent critical current density (J(c)) of 900 A cm(-2) (1800 A cm(-2) correc ted for porosity) at 77 K. The superconducting fibre was sensitive to magnetic field, which is evidence of weak coupling between the superco nducting grains.