US4354964A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cermet materials
Assignee: Thorn EMI Ltd
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Filing: 1980-11-10
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Granted: 1982-10-19
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Expires: 2000-11-10
Abstract
Abstract An electrically conducting cermet comprises a sintered compact of refractory oxide granules such as alumina granules having diameters of from 50 to 800 microns and a conductive network extending through the cermet and provided by a layer of one or more of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, iron, cobalt or nickel surrounding the individual oxide granules and constituting a volume fraction of 0.04 to 0.2 of the total cermet, wherein particles of one or more of said metals are dispersed within the oxide granules in a volume fraction of 0.01 to 0.15 of the granules, which granules also contain 0.01 to 0.25 percent by weight of magnesium oxide.
Inventors
- 👤 Peter Hing
- 👤 Ronald Kay
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:14
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/36; C; C04; C04B; C04B35/00; C04B35/01; C04B35/10; C04B35/111; C04B35/71; C22; C22C; C22C29/00; C22C29/12; H01B; H01B1/00; H01B1/14; H01B1/16
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
196 words
An electrically conducting cermet comprising a sintered compact of granules of refractory oxide selected from the group consisting of aluminum oxide, yttrium oxide and a spinel, said granules having diameters of from 50 to 800 microns, said granules being dispersed within a conductive network extending throughout the cermet, wherein said conductive network is constituted by a layer of particles surrounding said granules, said particles being of at least one metal selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, iron, cobalt and nickel, and being of a particle size of from 0.1 to 12 microns, said layer constituting a volume fraction of from 0.04 to 0.2 of the total cermet, wherein there is dispersed, within the refractory oxide granules, (a) particles of at least one metal selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, iron, cobalt and nickel, of a particle size of from 0.1 to 15 microns and in a volume fraction of from 0.01 to 0.15 of the total volume of the granules, and (b) from 0.01 to 0.25 percent by weight of the refractory oxide of finely divided magnesium oxide.
Claim 2
Dependent Claim
196 words
An electrically conducting cermet comprising a sintered compact of granules of refractory oxide selected from the group consisting of aluminum oxide, yttrium oxide and a spinel, said granules having diameters of from 50 to 800 microns, said granules being dispersed within a conductive network extending throughout the cermet, wherein said conductive network is constituted by a layer of particles surrounding said granules, said particles being of at least one metal selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, iron, cobalt and nickel, and being of a particle size of from 0.1 to 12 microns, said layer constituting a volume fraction of from 0.04 to 0.2 of the total cermet, wherein there is dispersed, within the refractory oxide granules, (a) particles of at least one metal selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, iron, cobalt and nickel, of a particle size of from 0.1 to 15 microns and in a volume fraction of from 0.01 to 0.15 of the total volume of the granules, and (b) from 0.01 to 0.25 percent by weight of the refractory oxide of finely divided magnesium oxide.
Claim 3
Dependent Claim
18 words
A cermet according to claim 1, wherein the diameters of said granules are from 50 to 500 microns.
Claim 4
Dependent Claim
26 words
A cermet according to claim 1 or claim 2, wherein the mean diameter of said granules is in the range of from 225 to 250 microns.
Claim 5
Dependent Claim
29 words
A cermet according to claim 1, wherein the mean particle size of the metal particles dispersed within the granules and forming said layer is from 1 to 5 microns.
Claim 6
Dependent Claim
33 words
A cermet according to claim 1, wherein there is additionally dispersed within the granules from 0.01 to 0.25 percent by weight of the total weight of the granules of a rare earth oxide.
Claim 7
Dependent Claim
17 words
A cermet according to claim 5, wherein said rare earth oxide is yttrium oxide or ytterbium oxide.
Claim 8
Dependent Claim
32 words
A cermet according to claim 1, wherein the conductive network comprises only one of said metals, and wherein the particles dispersed within said refractory oxide granules comprise only one of said metals.
Claim 9
Dependent Claim
13 words
A cermet according to claim 1, wherein said refractory oxide is aluminum oxide.
Claim 10
Dependent Claim
56 words
A cermet according to claim 1, wherein said conductive network comprises a layer of at least one metal selected from the group consisting of niobium, tantalum, molybdenum and tungsten, and wherein said metal particles dispersed within said refractory oxide granules are selected from the group consisting of at least one of niobium, tantalum, molybdenum, and tungsten.
Claim 11
Dependent Claim
54 words
A cermet according to claim 9, wherein said conductive network comprises a layer of at least one metal selected from the group consisting of tantalum, molybdenum and tungsten, and wherein said metal particles dispersed within said refractory oxide granules are selected from at least one of the group consisting of tantalum, molybdenum and tungsten.
Claim 12
Dependent Claim
29 words
A cermet according to claim 10, wherein said conductive network comprises a layer of tungsten, and wherein said metal particles dispersed within said refractory oxide granules are of tungsten.
Claim 13
Dependent Claim
42 words
A cermet according to claim 11, wherein the mean particle size of the tungsten particles in said layer which provides said conductive network is about 5 microns, and wherein said layer constitutes a volume fraction of about 0.06 of the total cermet.
References Cited (Backward Citations)
GB1571084A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-10-18 | 1986-04-19 | 1986-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-10-18 | 1990-04-19 | 1990-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-10-18 | 1994-04-19 | 1994-10-19 | $7700.00 | Window Closed / Lapsed |