Superconductive fiberform ceramic composite
AssigneeThe Boeing Company
InventorsAnna L. Baker, Michael Strasik
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Abstract
Processes are provided for forming a superconductive composite, comprising a superconductive metal oxide and a ceramic. The composite may be formed in any desired shape. Liquid nitrogen can be held around the superconductor longer and delivered in a more controlled fashion and the composite has improved resistance to shatter and thermal shock. The ceramic also provides protection from atmospheric deterioration of the superconductive oxide.
Claims6
A ceramic composite comprising a felted mat of ceramic particles and superconductive metal oxide particles bound together with a cured sol-gel precursor binder, wherein:
- the ceramic particles include ceramic fibers selected from the group consisting of silica, alumina, mullite, zirconia, aluminosilicate, silicon nitride, and mixture thereof;
- the superconductive metal oxide particles include fibers selected from the group consisting of superconductive oxide fibers, superconductive oxide coated ceramic fibers, and mixtures thereof,
- the superconductive oxide coated ceramic fibers comprising a superconductive mixed metal oxide coating on a ceramic fiber;
- the uncured, sol-gel precursor binder is an aqueous solution of metal salts stabilized in solution with ethylene glycol, and organic acid, or mixtures thereof;
- wherein the superconductive metal oxide particles are present in sufficient amount to render the composite superconductive below the superconducting transition temperature of the superconductive metal oxide particles;
- and
- wherein the ceramic fibers are about 0.0625-4.0 inches (0.16-10.2 cm) long and about 1-3 micrometers in diameter.
A ceramic composite comprising a felted mat of ceramic fibers that are about 0.0625-4.0 inches (0.16-10.2 cm) long and about 1-3 micrometers in diameter bound together with a sol-gel of a superconductive metal oxide precursor, the composite being obtainable by the steps of:
- a) saturating the mat with the sol-gel wherein the sol-gel is an aqueous solution of metal salts stabilized in solution with ethylene glycol, an organic acid, or mixtures thereof;
- b) heating the saturated mat to about 920.degree. C. to cure the sol-gel;
- and
- c) cooling the mat after curing the sol-gel, the cooling occurring at a rate of about 1.degree. C./min. to about 450.degree. C. followed by heat treating at 450.degree. C. for about 4 hours.
A ceramic composite comprising a felted mat of ceramic fibers and superconductive metal oxide-coated ceramic fibers bound together with a cured binder formed from a sol-gel precursor, wherein:
- a) the fibers are about 0.0625-4.0 inches (0.16-10.2 cm) long and about 1-3 micrometers in diameter;
- b) the superconductive metal oxide-coated ceramic fibers are obtainable by:
- i) contacting ceramic fibers selected from the group consisting of silica, alumina, mullite, zirconia, aluminosilicate, silicon nitride, or mixtures thereof with a superconductive metal oxide sol-gel precursor, the precursor being an aqueous solution of metal salts to form the superconductive metal oxide stabilized in solution with ethylene glycol, an organic acid, and mixtures thereof;
- and
- ii) converting the precursor to a superconductive metal oxide coating on the ceramic fibers;
- and
- c) the binder is selected from the group consisting of alumina, silica, mullite, zirconia, silicon nitride, and mixtures thereof.
Dependencies are inferred from the claim text.