Mfr. of high-temp. superconductors in strand form - using multistage heat-treatment and conditioning sequence

摘要

High-temp. superconductors are mfd. in the form of strands with a melt-textured structure. A conductor strand of YBa2Cu3Ox, which may contain 1-50 wt. % Ag as an additive, is continuously passed through a heated space to provide a defined heat treatment and oxygenation of the material. The space is subdivided into at least three subsidiary chambers in the direction of movement of the superconductor, which chambers are at different oxygen partial pressures and different temps.. When using YBa2Cu3Ox without Ag additions, the first chamber pref. contains oxygen at 980-1040 deg. C, the second chamber contains inert gas at the same temp. and the third chamber contains oxygen gas and has a temp. profile (100-1020 deg. C for up to 20 minutes, followed by cooling at 0.5-5 deg. K to 960-980 deg. C), followed by the usual oxygenation heat treatment. When using superconductor material to which Ag has been added, the first chamber contains inert gas or oxygen at 915-960 deg. C, the material is cooled in the second chamber to less than 910 deg. C under gas/oxygen mixt. (0.05-1 vol. % oxygen), and the usual oxygenation heat treatment is carried out in the third chamber. USE/ADVANTAGE - Suggested uses for the semiconductor material are for magnets, electrical machines and power transmission cables. Simplifies existing technology for superconductor strand mfr. enables higher max. current densities to be obtd..