United States of America As Represented by the Secretary of the Air Force

Westinghouse Electric Corporation

The United States of America As Represented by the United States

George J Bich

Tapan K Gupta

William N Lawless

James D Smith

Thomas M Burke

The composite insulation coating consists of a mixture of glass and ceramic oxide(s), coated onto a wire by conventional wire enameling techniques followed by heat treatment at 600.degree.-850.degree. C. The enamel when initially applied, the 'green' coat slurry, consists of four components: (1) the glass, (2) an inorganic filler (ceramic oxide powder, (3) an organic binder and (4) an organic solvent. The glasses can be selected from several commercial glasses (Corning 7570 and 7050) as well as Westinghouse glasses A-508, M 3072 and M 3073. None of these glasses contain lead or boron, allowing for nuclear applications. Suitable ceramic fillers are alumina, and the CeramPhysics, Inc. ceramics SC1C and SC1A. Organic binder materials and solvents are used. It is preferable that a copper wire to be coated with Ni, Inconel or Cr prior to coating with the subject insulation. For superconductors, the brittle nature of Nb.sub.3 Sn wire and the high reaction temperature (.about.700.degree. C.) required to form it preclude the use of standard organic insulation systems. The inorganic insulation with SC1C and SC1A ceramics, characterized by unusually high specific heats and thermal conductivities at cryogenic temperatures, offers the opportunity of providing increased enthalpy stabilization in a superconducting winding. The glass and ceramic is chosen so that the vitrification temperature of the composite coincides with the reaction temperature of 600.degree.-800 .degree. C. The most successful glasses meeting this criterion are A-508 and M3072.

Method of coating superconductors with inorganic insulation

The need for high current, high field, low loss, stable superconductors has led to the development of multifilamentary Nb.sub.3 Sn as the most promising candidate for use in superconducting machines. However, the brittle nature of Nb.sub.3 Sn and the high reaction temperature (.about.700.degree. C.) required to form it preclude the use of standard organic insulation systems. A recently developed class of high temperature dielectric materials which are characterized by unusually large specific heats and thermal conductivities at cryogenic temperatures offers the opportunity of providing increased enthalpy stabilization in a superconducting winding, as well as the required dielectric strength. The inorganic insulation system consists of a composite glass and ceramic powder vitrified at a temperature which coincides with the superconducting formation temperature of 600.degree.-800.degree. C. The glass and the ceramic is chosen in such a way that the vitrification temperature of the composite coincides with the reaction temperature of 600.degree.-800.degree. C. The most successful glasses meeting this criterion are two Westinghouse glasses designated A-508 and M3072. Suitable ceramic fillers are Al.sub.2 O.sub.3 and the Ceram Physics, Inc. ceramics SClC and SClA. Organic binders and solvents are used. Cladding with, e.g., nickel is preferable for the copper layer of Nb.sub.3 Sn wire.

Inorganic wire insulation for super-conducting wire

A method of curing an anaerobic resin, which primarily contains acrylic resin, includes externally catalyzing the cure of the resin with a metal-beta keto ester complex having the structural formula: ##STR1## where M is a transition metal; R.sub.1 is selected from the group consisting of alkyl groups having from 1 to 20 carbon atoms, benzene, naphthalene, anthracene, and hydrocarbon substituted aromatic; R.sub.2 and R.sub.3 are selected from hydrogen, alkyl groups having from 1 to 20 carbon atoms, benzene, naphthalene, anthracene and hydrocarbon substituted aromatic; R.sub.4 is selected from alkyl groups having from 1 to 20 carbon atoms; and n is equal to the valence of the metal M.

Substrate pretreatment with a metal-beta keto ester complex in the

An electromagnetic coil for high temperature and high radiation application in which glass is used to insulate the electrical wire. A process for applying the insulation to the wire is disclosed which results in improved insulation properties.

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Pittsburgh, PA, United States of America

George J Bich