Surface texturing of superconductors by controlled oxygen pressure
AssigneeIllinois Superconductor Corporation
InventorsNan Chen, Kenneth C. Goretta, Stephen E. Dorris
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Abstract
A method of manufacture of a textured layer of a high temperature superconductor on a substrate. The method involves providing an untextured high temperature superconductor material having a characteristic ambient pressure peritectic melting point, heating the superconductor to a temperature below the peritectic temperature, establishing a reduced pO.sub.2 atmosphere below ambient pressure causing reduction of the peritectic melting point to a reduced temperature which causes melting from an exposed surface of the superconductor and raising pressure of the reduced pO.sub.2 atmosphere to cause solidification of the molten superconductor in a textured surface layer.
Claims22
A method of preparing a textured layer of a high temperature superconductor on a substrate, comprising the steps of:
- providing an untextured high temperature superconductor having a characteristic ambient pressure peritectic melting point;
- heating said superconductor to a temperature below the peritectic temperature;
- establishing a reduced pO.sub.2 atmosphere below atmospheric pressure thereby causing reduction of the peritectic melting point to a reduced peritectic temperature point thereby causing melting from an exposed surface of said superconductor;
- and
- raising pressure of the reduced pO.sub.2 atmosphere to cause solidification of molten superconductor in a textured surface layer on the substrate.
A method of preparing a textured layer of a high temperature superconductor on an untextured high temperature superconductor substrate with the superconductor having a characteristic peritectic phase diagram, comprising the steps of:
- providing a substrate of an untextured high temperature superconductor specimen;
- disposing said substrate in a first pO.sub.2 atmosphere having a first pressure and then reducing the pO.sub.2 pressure below the first pressure to a reduced gas pressure, said reduced gas pressure causing controlled reduction of the peritectic melting point of said high temperature superconductor substrate below its ambient pressure peritectic melting point;
- subjecting said high temperature superconductor substrate to an elevated temperature below the ambient pressure peritectic melting point but above the reduced gas pressure peritectic melting point to cause melting from an exposed surface of said high temperature superconductor substrate adjacent the reduced gas pressure;
- and
- raising the pO.sub.2 pressure of the reduced gas pressure to cause solidification of molten high temperature superconductor formed in a surface layer on said high temperature superconductor substrate, thereby forming said textured layer of high temperature superconductor on the untextured high temperature superconductor substrate.
A method of preparing a textured layer of a high temperature superconductor of rare earth-123 superconductor, comprising the steps of:
- providing an untextured high temperature superconductor specimen;
- disposing said superconductor specimen in a pO.sub.2 atmosphere and heating to a temperature below the peritectic melting point of said superconductor in said pO.sub.2 atmosphere;
- lowering pressure of the pO.sub.2 atmosphere above said superconductor specimen to cause reduction of the peritectic melting point and to cause melting from an exposed surface of said superconductor specimen and formation of a molten superconductor layer;
- and
- raising pressure of the pO.sub.2 atmosphere to cause solidification of the molten superconductor layer in a textured surface layer of said specimen.
Dependencies are inferred from the claim text.