US4234338A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermal shock resistance ceramic insulator
Assignee: United States Department of Energy
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Filing: 1978-12-28
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Granted: 1980-11-18
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Expires: 1998-12-28
Abstract
Abstract Thermal shock resistant cermet insulators containing 0.1-20 volume % metal present as a dispersed phase. The insulators are prepared by a process comprising the steps of (a) providing a first solid phase mixture of a ceramic powder and a metal precursor; (b) heating the first solid phase mixture above the minimum decomposition temperature of the metal precursor for no longer than 30 minutes and to a temperature sufficiently above the decomposition temperature to cause the selective decomposition of the metal precursor to the metal to provide a second solid phase mixture comprising particles of ceramic having discrete metal particles adhering to their surfaces, said metal particles having a mean diameter no more than 1/2 the mean diameter of the ceramic particles, and (c) densifying the second solid phase mixture to provide a cermet insulator having 0.1-20 volume % metal present as a dispersed phase.
Inventors
- 👤 Chester S. Morgan
- 👤 William R. Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:46
CPC Classifications
H; H01; H01B; H01B3/00; H01B3/02; H01B3/12; B; B22; B22F; B22F9/00; B22F9/02; B22F9/023; B22F9/16; B22F9/30; C; C22; C22C; C22C29/00; H01B3/002; H01B3/006
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
164 words
A process for fabricating a cermet exhibiting thermal shock resistance and electrical insulating properties and containing 0.1-20 vol.% metal present as a discontinuous phase, said process comprising the steps of: (a) providing a first solid phase mixture of a ceramic powder and a metal precursor; (b) heating said first solid phase mixture above the minimum decomposition temperature of said metal precursor for no longer than about 30 minutes and to a temperature sufficiently above said decomposition temperature to cause the selective decomposition of said metal precursor to said metal to provide a second solid phase mixture of particles of said ceramic powder and discrete metal particles with the latter adhering to the surfaces of said ceramic particles, said metal particles having a mean diameter no more than 1/2 the mean diameter of said ceramic particles, and (c) densifying said second solid phase mixture to provide a cermet having 0.1-20 vol.% metal present therein as a discontinuous phase at the boundaries of the ceramic particles.
Claim 2
Dependent Claim
164 words
A process for fabricating a cermet exhibiting thermal shock resistance and electrical insulating properties and containing 0.1-20 vol.% metal present as a discontinuous phase, said process comprising the steps of: (a) providing a first solid phase mixture of a ceramic powder and a metal precursor; (b) heating said first solid phase mixture above the minimum decomposition temperature of said metal precursor for no longer than about 30 minutes and to a temperature sufficiently above said decomposition temperature to cause the selective decomposition of said metal precursor to said metal to provide a second solid phase mixture of particles of said ceramic powder and discrete metal particles with the latter adhering to the surfaces of said ceramic particles, said metal particles having a mean diameter no more than 1/2 the mean diameter of said ceramic particles, and (c) densifying said second solid phase mixture to provide a cermet having 0.1-20 vol.% metal present therein as a discontinuous phase at the boundaries of the ceramic particles.
Claim 3
Dependent Claim
86 words
The process of claim 1 wherein said ceramic powder is selected from the group of BN, B 4 C, Si 3 N 4 , TiC, Al 2 O 3 , ZrO 2 , MgO, ZnO, CaO, WO 3 , BeO, CoO, MnO 2 , Cr 2 O 3 , Y 2 O 3 , the lanthanide oxides, SnO 4 , TaO, Cu 2 O, BeO, NiO, the oxides of iron, the oxides of uranium, the oxides of thorium, the oxides of niobium, mullite and magnesia-alumina spinel.
Claim 4
Dependent Claim
62 words
The process of claim 1 wherein said metal precursor is selected from the group of TaH 0 .5, UH 3 , ZrH 2 , ThH 2 , W(CO) 6 , Fe(NO 3 ) 3 , ReCl 3 , PtCl 4 , PtF 3 , CoCl 2 , WO 3 , MoO 3 , CrCl 2 , and Cr(NO 3 ) 3 .
Claim 5
Dependent Claim
36 words
The process of claim 1 wherein said heating step (b) is carried out by heating said first solid phase mixture at a temperature at least 300° C. above the minimum decomposition temperature of said metal precursor.
Claim 6
Dependent Claim
32 words
The process of claim 1 wherein the ceramic is Al 2 O 3 and the metal precursor is PtCl 4 and said heating step (b) is performed to at least 850° C.
Claim 7
Dependent Claim
15 words
The process of claim 5 wherein the heating step is performed in a hydrogen atmosphere.
Claim 8
Dependent Claim
14 words
The process of claim 1 in which said cermet contains 0.5-2 volume % metal.
Claim 9
Dependent Claim
11 words
The cermet prepared by the method of claims 1 or 5.
Claim 10
Dependent Claim
17 words
The cermet of claims 1 or 5 wherein said metal phase is uniformly dispersed throughout said cermet.
Claim 11
Dependent Claim
102 words
A process for preparing a cermet electrical insulator characterized by exhibiting resistance to thermal shock, comprising Al 2 O 3 and 0.1-3 volume % Pt present as a discontinuous metal phase, said process comprising the steps of: (a) providing a first solid phase mixture of Al 2 O 3 and PtCl 4 powders, (b) heating said first solid phase mixture to at least 800° C. for about 5-15 minutes to decompose said PtCl 4 to Pt, forming a second solid phase mixture, and (c) densifying said second solid phase mixture to provide a cermet having Pt present therein as a discontinuous phase.
Claim 12
Dependent Claim
102 words
A process for preparing a cermet electrical insulator characterized by exhibiting resistance to thermal shock, comprising Al 2 O 3 and 0.1-3 volume % Pt present as a discontinuous metal phase, said process comprising the steps of: (a) providing a first solid phase mixture of Al 2 O 3 and PtCl 4 powders, (b) heating said first solid phase mixture to at least 800° C. for about 5-15 minutes to decompose said PtCl 4 to Pt, forming a second solid phase mixture, and (c) densifying said second solid phase mixture to provide a cermet having Pt present therein as a discontinuous phase.
Claim 13
Dependent Claim
19 words
The process of claim 10 in which said heating step (b) is performed in atmosphere comprising H 2 .
References Cited (Backward Citations)
US3044867A
Cited
US2952535A
Cited
US3069292A
Cited
US3150974A
Cited
US3192042A
Cited
US3158473A
Cited
US3143789A
Cited
US3698891A
Cited
US3964878A
Cited
US4155758A
Cited
US4073647A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-11-18 | 1984-05-19 | 1984-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-18 | 1988-05-19 | 1988-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-18 | 1992-05-19 | 1992-11-18 | $7700.00 | Window Closed / Lapsed |