A Practical Process to Densify High Temperature Superconducting Bi2Sr2CaCu2O8+x (2212) Round Wire Before Coil Winding
This invention describes the processing of Bi2Sr2CuO6+x (2122) oxide superconducting round wires so as to obtain a magnet with a dense and stable winding pack mad of dense, highly-textured oxide superconductor with high critical current density.
The present invention overcomes the limitations of the prior art by pre-densifying the 2212 wire before it is wound on the coil form. The invention significantly reduces, and can even eliminate, the decrease in wire diameter that occurs during the final heat treatment when the coil receives its final OP heat treatment, thus avoiding changes to the geometry of the coil.
The advantages of round wire, compared to tape, are its ability to be twisted, its electromagnetic isotrpy and its ability to be easily cabled.