US4398980A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for fabricating a seal between a ceramic and a metal alloy
Assignee: United States Department of Energy
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Filing: 1981-07-24
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Granted: 1983-08-16
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Expires: 2001-07-24
Abstract
Abstract A method of fabricating a seal between a ceramic and an alloy comprising the steps of prefiring the alloy in an atmosphere with a very low partial pressure of oxygen, firing the assembled alloy and ceramic in air, and gradually cooling the fired assembly to avoid the formation of thermal stress in the ceramic. The method forms a bond between the alloy and the ceramic capable of withstanding the environment of a pressurized water reactor and suitable for use in an electrical conductivity sensitive liquid level transducer.
Inventors
- 👤 Paul V. Kelsey, Jr.
- 👤 William T. Siegel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 03:27
CPC Classifications
C; C04; C04B; C04B37/00; C04B37/02; C04B37/021; B; B23; B23K; B23K35/00; B23K35/22; B23K35/38; G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/06; G01N27/07; C04B2235/00; C04B2235/65; C04B2235/656; C04B2235/6567; C04B2235/658; C04B2235/6582; C04B2237/00; C04B2237/30; C04B2237/32; C04B2237/34; C04B2237/341; C04B2237/40; C04B2237/403; C04B2237/405; C04B2237/50; C04B2237/52; C04B2237/525; C04B2237/54; Y; Y10; Y10S; Y10S228/00; Y10S228/903
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
94 words
A method of fabricating a seal between a ceramic and a metal alloy comprising: prefiring the alloy in a reducing atmosphere with an oxygen partial pressure less than or equal to 10 -10 Pa, cooling the alloy in said reducing atmosphere, placing the ceramic in contact with the alloy, firing the ceramic and alloy in air, and cooling the ceramic and alloy to a temperature below a firing temperature but above ambient temperature, holding at said temperature for a set period of time, then cooling to ambient temperature whereby a seal is formed therebetween.
Claim 2
Independent Claim
94 words
A method of fabricating a seal between a ceramic and a metal alloy comprising: prefiring the alloy in a reducing atmosphere with an oxygen partial pressure less than or equal to 10 -10 Pa, cooling the alloy in said reducing atmosphere, placing the ceramic in contact with the alloy, firing the ceramic and alloy in air, and cooling the ceramic and alloy to a temperature below a firing temperature but above ambient temperature, holding at said temperature for a set period of time, then cooling to ambient temperature whereby a seal is formed therebetween.
Claim 3
Dependent Claim
27 words
The method of claim 1 wherein the prefiring of the alloy is done in an atmosphere with an oxygen partial pressure of less than 10 -14 Pa.
Claim 4
Dependent Claim
20 words
The method of claim 1 wherein the prfiring of the alloy is of a duration of 1 to 4 hours.
Claim 5
Dependent Claim
20 words
The method of claim 3 wherein the prefiring of the alloy is carried out at a temperature between 950°-1150° C.
Claim 6
Dependent Claim
24 words
The method of claim 1 wherein the firing of the ceramic and alloy in air is of a duration of 5 to 30 minutes.
Claim 7
Dependent Claim
22 words
The method of claim 5 wherein the firing of the ceramic and alloy is carried out at a temperature between 950°-1150° C.
Claim 8
Dependent Claim
38 words
The method of claim 6 wherein the firing of the ceramic and alloy is carried out so that the temperature of the ceramic and alloy rises from ambient temperature to about 1050° C. in less than 2 minutes.
Claim 9
Dependent Claim
36 words
The method of claim 1 wherein the fired ceramic and alloy are cooled from firing temperature to about 800° C. and are held at about 800° C. for about three minutes before cooling to ambient temperature.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-15 | 1987-02-14 | 1987-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-15 | 1991-02-14 | 1991-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-15 | 1995-02-14 | 1995-08-16 | $7700.00 | Window Closed / Lapsed |