EP0272687A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Tungsten duplex composite electrode and filament material
Assignee: Osram Sylvania Inc
•
Filing: 1987-12-22
•
Granted: —
•
Expires: 2007-12-22
Abstract
Abstract The present invention provides a tungsten-based duplex composite member, e.g., wire or rod, which combines the emissive, nonsag, or other desirable qualities of an inner tungsten-based core material with a different combination of properties, for example, resistance to attack, by the presence of a different tungsten-based material as an outer sheath or shell surrounding the core material. In one embodiment of the present invention, an electrode is formed from a duplex composite member, composed of a thoriated tungsten core (W - ThO2) and a thin rhenium (Re) shell. Other embodiments of duplex composite members are provided by thoriated tungsten discharge electrodes in which it is desirable to have two different concentrations of thoria (ThO2) in the element, a first concentration in the core of the duplex composite member and a second concentration in the shell or surface of the member.
Inventors
- 👤 Edmund M. Passmore
- 👤 Thomas J. Patrician
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 03:07
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/04; H01J61/06; H01J61/073; H01J61/0735; H01J61/0737
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
30 words
A tungsten-based duplex composite member, comprising a core composed of a first tungsten-based material and an outer sheath or shell surrounding the core composed of a second, different tungsten-based material.
Claim 2
Dependent Claim
30 words
A tungsten-based duplex composite member, comprising a core composed of a first tungsten-based material and an outer sheath or shell surrounding the core composed of a second, different tungsten-based material.
Claim 3
Dependent Claim
16 words
The tungsten-based duplex composite member of claim 1, wherein the core is composed of thoriated tungsten.
Claim 4
Dependent Claim
24 words
The tungsten-based duplex composite member of claim 2, wherein the thoria concentration in the core material is from about 0.5 to about 5 percent.
Claim 5
Dependent Claim
24 words
The tungsten-based duplex composite member of claim 2, wherein the thoria concentration in the core material is from about 1 to about 3 percent.
Claim 6
Dependent Claim
20 words
The tungsten-based duplex composite member of claim 2, wherein the thoria concentration in the core material is about 2 percent.
Claim 7
Dependent Claim
16 words
The tungsten-based duplex composite member of claim 1, wherein the shell is composed of thoriated tungsten.
Claim 8
Dependent Claim
24 words
The tungsten-based duplex composite member of claim 6, wherein the thoria concentration in the shell material is from about 0.5 to about 5.0 percent.
Claim 9
Dependent Claim
24 words
The tungsten-based duplex composite member of claim 6, wherein the thoria concentration in the shell material is from about 1 to about 3 percent.
Claim 10
Dependent Claim
20 words
The tungsten-based duplex composite member of claim 6, wherein the thoria concentration in the shell material is about 1 percent.
Claim 11
Dependent Claim
26 words
The tungsten-based duplex composite member of claim 1, wherein the thoria concentration in the shell material is lower than the thoria concentration in the core material.
Claim 12
Dependent Claim
22 words
The tungsten-based duplex composite member of claim 10, comprising a 2 percent thoriated tungsten core and a 1 percent thoriated tungsten shell.
Claim 13
Dependent Claim
17 words
The tungsten-based duplex composite member of claim 11, which is in the form of an electrode rod.
Claim 14
Dependent Claim
17 words
The tungsten-based duplex composite member of claim 11, which is in the form of a filament wire.
Claim 15
Dependent Claim
16 words
The tungsten-based duplex composite member of claim 13, which has a diameter of about 0.017 inches.
Claim 16
Dependent Claim
22 words
The tungsten-based duplex composite member of claim 1, wherein the core and/or the shell are composed of a potassium doped nonsag tungsten.
Claim 17
Dependent Claim
30 words
The tungsten-based duplex composite member of claim 15, wherein the dopant concentration in the core material is from about 0.001 to about 0.1 percent (10 to 100 parts per million).
Claim 18
Dependent Claim
24 words
The tungsten-based duplex composite member of claim 15, wherein the dopant concentration in the shell material is from about 0.001 to about 0.01 percent.
Claim 19
Dependent Claim
23 words
The tungsten-based duplex composite member of claim 1, wherein the either the core or the shell is composed of commercially pure (undoped) tungsten.
Claim 20
Dependent Claim
20 words
The tungsten-based duplex composite member of claim 1, wherein the core and/or the shell are composed of a tungsten alloy.
Claim 21
Dependent Claim
22 words
The tungsten-based duplex composite member of claim 1, wherein the core and/or the shell are composed of tungsten and an emitter material.
Claim 22
Dependent Claim
24 words
The tungsten-based duplex composite member of claim 20, wherein the emitter concentration in the core material is from about 0.5 to about 5.0 percent.
Claim 23
Dependent Claim
24 words
The tungsten-based duplex composite member of claim 20, wherein the emitter concentration in the shell material is from about 0.5 to about 5.0 percent.
Claim 24
Dependent Claim
24 words
The tungsten-based duplex composite member of claim 1, wherein either the core or the shell is composed of tungsten and about 20 ppm aluminum.
Claim 25
Dependent Claim
15 words
The tungsten-based duplex composite member of claim 1, wherein the shell comprises a tungsten-rhenium alloy.
Claim 26
Dependent Claim
18 words
The tungsten-based duplex composite member of claim 24, wherein the rhenium concnetration is up to about 5 percent.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.