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Superconducting Films by Web Coating

IP.com Disclosure Number: IPCOM000036026D
Original Publication Date: 1989-Aug-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 1 page(s) / 13K

Publishing Venue

IBM

Related People

Brady, MJ: AUTHOR [+3]

Abstract

Techniques for fabrication of films, pellets, and targets of high Tc oxide superconductors, such as Y-Ba-Cu-O have included processes such as E-beam deposition, co-evaporation, sputtering, and, recently, plasma arc spraying, but these methods have limitations. It is desirable to be able to deposit films (thick or thin) at reasonable deposition rates and low substrate temperatures, with fine control of deposition parameters and the ability to pattern or delineate. It is also necessary to be able to make wires and ribbons reproducibly and inexpensively.

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Superconducting Films by Web Coating

Techniques for fabrication of films, pellets, and targets of high Tc oxide superconductors, such as Y-Ba-Cu-O have included processes such as E-beam deposition, co-evaporation, sputtering, and, recently, plasma arc spraying, but these methods have limitations. It is desirable to be able to deposit films (thick or thin) at reasonable deposition rates and low substrate temperatures, with fine control of deposition parameters and the ability to pattern or delineate. It is also necessary to be able to make wires and ribbons reproducibly and inexpensively.

These goals can be achieved using web coating, a process that is utilized for printing, magnetics (films), and photoconductor technologies. The reacted or unreacted powders of the superconducting material are incorporated in a slurry or binder, which acts as a carrier in the production of ribbons and patterned wires. The coating is formed at room temperature, is inexpensive, safe from a manufacturing point of view, and is extremely controllable. By treating the coating appropriately at high temperatures, it can be made into superconducting devices.

The method consists of three steps. In the first, proportions of Y2O3, BaCO3, and CuO powder are ball milled in a suitable fluid medium, such as methanol, to a fine sized mixture, with a particle size typically of about one micron. The fluid is then allowed to evaporate. A slurry is then made using a solvent which binds the particles sufficiently, so that it can be web-coated on a continuously moving web. The binding solvent will burn off during the solid-state reaction process, leaving only the superconducting material. During the web- coating process the material can now be formed into patterns of a desired configuration. These patterns can be obtained in two ways: a web, (subst...