US3764776A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making coherent shape of silicon carbide
Assignee: Emerson Electric Co
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Filing: 1972-02-28
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Granted: 1973-10-09
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Expires: 1992-02-28
Abstract
Abstract A coherent shape of silicon carbide is produced by heating particulate silicon carbide to a temperature above 3,000* F. and below 5,500* F. and subsequently cooling the silicon carbide below 3,000* F., both steps being completed within a period of 30 minutes. In the preferred method, the particulate silicon carbide is exposed to the energy of a laser beam, and the particulate silicon carbide has a minimum particle size greater than ten microns. The preferred shape has a core with a relatively low resistivity of the magnitude of the order of 0.05 to 100 ohms per linear inch and a distinctly delineated rind with a relatively high resistivity which may be removed if lower thermal mass is required by a specific application.
Inventors
- 👤 F Hierholzer
- 👤 J Ancona
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:41
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/56; C04B35/565; B; B23; B23K; B23K26/00; B23K26/36; B23K26/40; C04B33/00; C04B33/32; H; H05; H05B; H05B3/00; H05B3/10; H05B3/12; H05B3/14; H05B3/148; B23K2103/00; B23K2103/50; B23K2103/52; H05B2203/00; H05B2203/027
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
56 words
A method of forming a coherent shape of silicon carbide comprising the steps of selectively heating unconsolidated particulate silicon carbide by means of an uncharged energy beam to a temperature above 3,000* F. and below 5,500* F. and subsequently cooling the silicon carbide below 3,000* F., both steps being completed within a period of 10 minutes.
Claim 2
Independent Claim
60 words
A method of forming a coherent shape of silicon carbide comprising sequentially exposing particulate silicon carbide to the energy of a laser beam for a period of less than 10 minutes, said particulate silicon carbide being heated by said laser beam to a temperature above 3,000* F. and below 5,500* F. within said period and thereafter cooled below 3,000* F.
Claim 3
Independent Claim
61 words
A method of forming a coherent shape of silicon carbide comprising exposing particulate silicon carbide to the energy of a laser beam for a period of less than ten minutes, said laser beam being emitted by a carbon dioxide laser and having a wave length of approximately 10.6 microns, and the particulate silicon carbide having particle sizes greater than ten microns.
Claim 4
Dependent Claim
42 words
The method of claim 4 wherein the laser beam and a bed of particulate silicon carbide are moved relative to one another at a rate such that none of the silicon carbide particles is exposed to said beam more than 30 seconds.
Claim 5
Dependent Claim
23 words
The method of claim 3 wherein the particulate silicon carbide is exposed to the laser beam in an air atmosphere at atmospheric pressure.
Claim 6
Dependent Claim
16 words
The method of claim 3 wherein the particulate silicon carbide is doped to make it semiconductive.
Claim 7
Dependent Claim
10 words
The method of claim 7 wherein the dopant is aluminum.
Claim 8
Independent Claim
93 words
A method of forming a coherent shape of silicon carbide comprising directing onto unconsolidated particulate silicon carbide a laser beam with energy sufficient to raise the temperature of said particulate silicon carbide above 3,000* F. and below 5,500* F., moving the particulate silicon carbide and laser beam with respect to one another and controlling the rate of said movement to cause said particulate silicon carbide to heat between 3,000* and 5,500* F. and to be removed from an area of impingement by said laser beam in a period of less than 20 seconds.
Claim 9
Independent Claim
120 words
A method of forming a silicon carbide heating element comprising forming a bed of particulate P-doped silicon carbide, directing a laser beam onto the surface of said bed to cause particulate silicon carbide upon which the beam is directed to heat to a temperature above 3,000* F. and below 5,500* F., moving said bed and beam relative to one another in a predetermined, element-shaped pattern, heating the particles at the ends of the element to a greater degree than the particles intermediate the ends, the rate of relative movement of the two being such as to cause the particles to heat above 3,000* F. and cool below 3, 000* F. all in a time span of less than 10 minutes.
Claim 10
Dependent Claim
37 words
The method of claim 10 wherein thE bed is exposed to air during the element forming process, and the rate of relative movement is such as to produce a heating cycle time of less than 30 seconds.
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) | 1976-10-08 | 1977-04-09 | 1977-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-08 | 1981-04-09 | 1981-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-08 | 1985-04-09 | 1985-10-09 | $7700.00 | Window Closed / Lapsed |