US4190637A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Graphite having improved thermal stress resistance and method of preparation
Assignee: United States Department of Energy
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Filing: 1978-07-18
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Granted: 1980-02-26
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Expires: 1998-07-18
Abstract
Abstract An improved method for fabricating a graphite article comprises the steps of impregnating a coke article by first heating the coke article in contact with a thermoplastic pitch at a temperature within the range of 250 DEG -300 DEG C. at a pressure within the range of 200-2000 psig for at least 4-10 hours and then heating said article at a temperature within the range of 450 DEG -485 DEG C. at a pressure of 200-2000 psig for about 16-24 hours to provide an impregnated article; heating the impregnated article for sufficient time to carbonize the impregnant to provide a second coke article, and graphitizing the second coke article. A graphite having improved thermal stress resistance results when the coke to be impregnated contains 1-3 wt.% sulfur and no added puffing inhibitors. An additional improvement in thermal stress resistance is achieved when the second coke article is heated above about 1400 DEG C. at a rate of at least 10 DEG C./minute to a temperature above the puffing temperature.
Inventors
- 👤 Charles R. Kennedy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 06:30
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/52; C04B35/521
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
136 words
A method for fabricating a graphite article comprising the steps of: (a) providing a first coke article containing 1-3 wt.% sulfur and no added puffing inhibitors; (b) impregnating said first coke article with a thermoplastic pitch by first heating said first coke article in contact with said thermoplastic pitch at a temperature within the range of 250°-300° C. at a pressure within the range of 200-2000 psig for at least 4-10 hours, and then heating said article at a temperature within the range of 465°-485° C. at a pressure of 200-2000 psig for about 16-24 hours to provide an impregnated article; (c) heating said impregnated article for sufficient time to carbonize the impregnant to provide a second coke article; and (d) graphitizing the second coke article at a temperature above the temperature at which puffing occurs.
Claim 2
Independent Claim
136 words
A method for fabricating a graphite article comprising the steps of: (a) providing a first coke article containing 1-3 wt.% sulfur and no added puffing inhibitors; (b) impregnating said first coke article with a thermoplastic pitch by first heating said first coke article in contact with said thermoplastic pitch at a temperature within the range of 250°-300° C. at a pressure within the range of 200-2000 psig for at least 4-10 hours, and then heating said article at a temperature within the range of 465°-485° C. at a pressure of 200-2000 psig for about 16-24 hours to provide an impregnated article; (c) heating said impregnated article for sufficient time to carbonize the impregnant to provide a second coke article; and (d) graphitizing the second coke article at a temperature above the temperature at which puffing occurs.
Claim 3
Dependent Claim
15 words
The method of claim 1 wherein said graphitization step is carried out above 3100° C.
Claim 4
Dependent Claim
37 words
The method of claim 1 wherein said second coke article is heated at a heating rate of at least 10° C. per minute from about 1400° C. to a temperature above the temperature at which puffing occurs.
Claim 5
Dependent Claim
14 words
The method of claim 1 wherein said first coke article contains about 1.60-1.75% sulfur.
Claim 6
Dependent Claim
53 words
The graphite article prepared by the method of claim 2 characterized by a density at least 1.75 gm/cm 3 , a fracture strain at least 1%, a 1000° C. coefficient of thermal expansion less than 5.5×10 -6 ° C. -1 and a thermal stress resistance of at least 0.2%/(°C. -1 ×10 6 ).
Claim 7
Dependent Claim
53 words
The graphite article prepared by the method of claim 3 characterized by a density at least 1.75 gm/cm 3 , a fracture strain at least 1.09%, a 1000° C. coefficient of thermal expansion less than 5×10 -6 ° C. -1 and a thermal stress resistance of at least 0.24%/(°C. -1 ×10 6 ).
Claim 8
Dependent Claim
15 words
The graphite of claim 5 further characterized by a Bacon Anisotropy factor less than 1.25.
Claim 9
Dependent Claim
15 words
The graphite of claim 6 further characterized by a Bacon Anisotropy factor less than 1.25.
Claim 10
Dependent Claim
56 words
A graphite article characterized by a density at least 1.75 gm/cm 3 , a fracture strain of at least 1%, a 1000° l C. coefficient of thermal expansion less than 5.5×10 -6 ° C. -1 , a thermal stress resistance of at least 0.2%/(°C. -1 ×10 6 ) and a Bacon Anisotropy factor less than 1.25.
Claim 11
Dependent Claim
56 words
A graphite article characterized by a density at least 1.75 gm/cm 3 , a fracture strain of at least 1%, a 1000° l C. coefficient of thermal expansion less than 5.5×10 -6 ° C. -1 , a thermal stress resistance of at least 0.2%/(°C. -1 ×10 6 ) and a Bacon Anisotropy factor less than 1.25.
Claim 12
Dependent Claim
40 words
The graphite article of claim 9 characterized by a fracture strain of at least 1.09%, a 1000° C. coefficient of thermal expansion less than 5×10 -6 , and a thermal stress resistance of at least 0.24%/(°C. -1 ×10 6 ).
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) | 1983-02-25 | 1983-08-27 | 1984-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-02-25 | 1987-08-27 | 1988-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-02-25 | 1991-08-27 | 1992-02-26 | $7700.00 | Window Closed / Lapsed |