US4374901A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Very fine diameter uniform wires
Assignee: RTX Corp
•
Filing: 1981-12-21
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Granted: 1983-02-22
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Expires: 2001-12-21
Abstract
Abstract Disclosed are very fine wires, of the order of 3-6×10 -6 m diameter, having cross sections which are uniform within ±3%. A common drawn tungsten wire is electrolytically etched to a fine diameter, of the order of 2-4×10 -6 m. The variations in cross sectional area along the etched wire are eliminated by selectively vapor depositing tungsten on the surface while using resistance heating. The very fine uniform wires enhance the performance of devices such as fluidic angular rate motion sensors.
Inventors
- 👤 Carl M. Ferrar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:13
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/04; C23C16/44; C23C16/54; C23C16/545; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12431; Y10T428/12438
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
70 words
A metal wire having a diameter of less than about 6×10 -6 m comprised of a drawn metal core having a cross sectional area variation of more than ±3% surrounded by a layer of vapor deposited material of essentially the same composition as the core, the wire having an overall cross sectional area variation of less than ±3%, both cross sectional area variations measured over lengths of about 10 mm.
Claim 2
Dependent Claim
70 words
A metal wire having a diameter of less than about 6×10 -6 m comprised of a drawn metal core having a cross sectional area variation of more than ±3% surrounded by a layer of vapor deposited material of essentially the same composition as the core, the wire having an overall cross sectional area variation of less than ±3%, both cross sectional area variations measured over lengths of about 10 mm.
Claim 3
Dependent Claim
29 words
The wire of claim 1 characterized by a core which has been chemically etched to about 3×10 -6 m prior to deposition of the layer of vapor deposited material.
Claim 4
Dependent Claim
17 words
The wire of claims 1 or 2 characterized by cross sectional area variation of less than ±1%.
Claim 5
Dependent Claim
14 words
The wire of claims 1 or 2 having a composition consisting essentially of tungsten.
Claim 6
Dependent Claim
19 words
A fluidic motion sensor utilizing a fine wire sensing element, characterized by a wire of claims 1 or 2.
Claim 7
Independent Claim
121 words
The method of making a fine metal wire of less than 6×10 -6 m characterized by drawing a circular cross section tungsten wire to a first diameter; electrolytically etching the wire to a second diameter smaller than the first diameter, the wire cross sectional area thereby being made non-uniform so that it varies by more than ±1% over a 10 mm length; and heating the etched wire using electric current in the presence of a heat decomposable reactant containing tungsten, to selectively deposit tungsten on the smaller cross sectional area portions of the wire, to increase the wire to a third diameter greater and more uniform in cross sectional area than characterized the wire when it was at its second diameter.
Claim 8
Independent Claim
121 words
The method of making a fine metal wire of less than 6×10 -6 m characterized by drawing a circular cross section tungsten wire to a first diameter; electrolytically etching the wire to a second diameter smaller than the first diameter, the wire cross sectional area thereby being made non-uniform so that it varies by more than ±1% over a 10 mm length; and heating the etched wire using electric current in the presence of a heat decomposable reactant containing tungsten, to selectively deposit tungsten on the smaller cross sectional area portions of the wire, to increase the wire to a third diameter greater and more uniform in cross sectional area than characterized the wire when it was at its second diameter.
Claim 9
Dependent Claim
18 words
The method of claim 6 characterized by resistively heating the wire using a constant current through the wire.
Claim 10
Dependent Claim
27 words
The method of claim 6 characterized by heating the etched wire in an atmosphere of WF 6 and H 2 , to a temperature between 250°-900° C.
Claim 11
Dependent Claim
28 words
The method of claim 6 characterized by heating the wire to 600°-700° C. in an atmosphere containing 5-15% WF 6 , at total pressure 0.1 to 0.9 atmospheres.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-02-21 | 1986-08-23 | 1987-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-21 | 1990-08-23 | 1991-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-21 | 1994-08-23 | 1995-02-22 | $7700.00 | Window Closed / Lapsed |