# US 8,784,993 B2 · High temperature high frequency magnet wire and method of making

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- Number: US 8,784,993 B2
- Document ID: US8784993B2
- Status: Granted
- Kind: B2
- Application number: 12/968,437
- Filed: 2010-12-15
- Published: 2012-06-21
- Granted: 2014-07-22
- Earliest claimed: 2010-12-15
- Assignees: General Electric Company
- Applicants: Weijun Yin; Kevin Warner Flanagan; Robert Colin McTigue; Mark Rodda; Sergei Kniajanski
- Inventors: Weijun Yin; Kevin Warner Flanagan; Robert Colin McTigue; Mark Rodda; Sergei Kniajanski
- Web page: https://patentgrep.com/patent/US8784993B2

## CPC

- H01F 41/066: with insulation
- H01B 3/006: {Other inhomogeneous material}
- H01B 3/306: {Polyimides or polyesterimides}
- H01B 7/29: Protection against damage caused by extremes of temperature or by flame {(heat dissipation or conduction H01B7/42)}
- C08K 9/06: with silicon-containing compounds
- Y10T 428/2995: Silane, siloxane or silicone coating
- Y10T 428/31681: Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A composite magnet wire includes, in an exemplary embodiment, a metal wire and a coating applied to an outer surface of the wire. The coating includes a polyimide polymer and a plurality of alumina nano particles dispersed in the polyimide polymer. The alumina nano particles have a surface treatment applied to outer surfaces of the alumina nano particles, where the surface treatment includes a phenyl-silane. The composite magnet wire has a thermal degradation temperature index of at least 300° C. as calculated in accordance with ASTM E1641 or D2307.

## Claims

### Claim 1

A composite magnet wire comprising:
a metal wire; and
a coating applied to an outer surface of said wire, said coating comprising a polyimide polymer comprising poly(biphenyltetracarboxylic dianhydride-co-phenylenediamine) and a plurality of alumina nano particles dispersed in said polyimide polymer, said alumina nano particles having a surface treatment applied to outer surfaces of said alumina nano particles, said surface treatment comprises a phenyl-silane;
said composite magnet wire having a thermal degradation temperature index of at least 300° C. as calculated in accordance with ASTM E1641 or ASTM D2307 (2005), wherein said coating comprises about 1% to about 6% by weight of said surface treated alumina nano particles, said coating on said outer surface has a thickness of about 25 μm to about 50 μm, and said alumina nano particles having an average particle size less than about 100 nanometers (nm).

### Claim 2 (depends on 1)

The composite magnet wire in accordance with claim 1, wherein said metal wire comprising at least one of copper or a copper alloy.

### Claim 3 (depends on 1)

The composite magnet wire in accordance with claim 1, wherein said alumina nano particles having an average particle size of about 20 nm to about 50 nm.

### Claim 4 (depends on 1)

The composite magnet wire in accordance with claim 1, wherein the metal wire comprises at least one of a silver plated copper wire, a nickel plated copper wire, a nickel cladded copper wire, an aluminum wire, or a copper cladded aluminum wire.

### Claim 5 (depends on 1)

The composite magnet wire in accordance with claim 1, wherein the phenyl-silane comprises at least one of trimethoxyphenylsilane, triethoxyphenylsilane, or mixtures thereof.

### Claim 6

A composite magnet wire, comprising:
a metal wire, wherein the metal wire is at least one of copper, a copper alloy, silver plated copper, nickel plated copper, nickel cladded copper, aluminum, or copper clad aluminum; and
a coating applied to an outer surface of said wire, said coating comprising a polyimide polymer and a plurality of alumina nano particles dispersed in said polyimide polymer, said alumina nano particles having a surface treatment applied to outer surfaces of said alumina nano particles, said surface treatment comprises a phenyl-silane;
wherein
the polyimide polymer comprises poly(biphenyltetracarboxylic dianhydride-co-phenylenediamine);
the phenyl-silane comprises at least one of trimethoxyphenylsilane, triethoxyphenylsilane, or mixtures thereof;
the coating comprises about 1% to about 10% by weight of the surface treated alumina nano particles;
the coating on said outer surface has a thickness of about 25 μm to about 50 μm; and
the alumina nano particles having an average particle size of about 20 nm to about 50 nm;
said composite magnet wire having a thermal degradation temperature index of at least 300° C. as calculated in accordance with ASTM E1641 or ASTM D2307 (2005).