US4707459A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reacting-bonded silicon carbide spheroids and process of making
Assignee: Tenmat Ltd
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Filing: 1984-11-06
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Granted: 1987-11-17
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Expires: 2004-11-06
Abstract
Abstract A method of producing spheroids comprising a coherent mixture of carbon and silicon carbide powders for subsequent siliconizing and if desired grinding to improve their sphericity, involves the steps of preparing a slip consisting essentially of a suspension of silicon carbide and carbon powders in a liquid, and introducing drops of the slip into a medium in which the drops form individual solid casts. The said liquid may be water to which a dispersant (which may be a deflocculent) has been added. Sodium alginate may advantageously be added to the slip. The said medium may be an aqueous solution of an electrolyte such as a calcium salt. An organic liquid phase, immiscible with the electrolyte, may be provided on the surface thereof. Examples of organic liquid are petroleum ether, kerosene, and cyclohexanol.
Inventors
- 👤 Peter Kennedy
- 👤 John O. Ware
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:46
CPC Classifications
C; C01; C01B; C01B32/00; C01B32/90; C01B32/914; C01B32/956; C01B32/963; C01B32/984; C01P; C01P2004/00; C01P2004/30; C01P2004/32; C01P2006/00; C01P2006/10
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
88 words
A method of producing silicon carbide-carbon spheroids, said method comprising preparing a slip consisting essentially of an aqueous suspension of silicon carbide and carbon powders and a dispersant, said dispersant being present in an amount effective to prevent flocculation; introducing drops of the slip into an aqueous solution of an electrolyte, said electrolyte being present in an amount effective to flocculate the silicon carbide and carbon powders and form individual solid spheroids comprising a coherent mixture of silicon carbide and carbon; and allowing the solid spheroids to precipitate.
Claim 2
Independent Claim
88 words
A method of producing silicon carbide-carbon spheroids, said method comprising preparing a slip consisting essentially of an aqueous suspension of silicon carbide and carbon powders and a dispersant, said dispersant being present in an amount effective to prevent flocculation; introducing drops of the slip into an aqueous solution of an electrolyte, said electrolyte being present in an amount effective to flocculate the silicon carbide and carbon powders and form individual solid spheroids comprising a coherent mixture of silicon carbide and carbon; and allowing the solid spheroids to precipitate.
Claim 3
Dependent Claim
23 words
The method of claim 1, wherein the electrolyte present in the aqueous solution into which the drops are introduced is a calcium salt.
Claim 4
Dependent Claim
32 words
The method of claim 1, further comprising providing an organic liquid layer on the surface of the aqueous solution of an electrolyte, said organic liquid being substantially immiscible with said aqueous solution.
Claim 5
Dependent Claim
21 words
The method of claim 3, wherein the organic liquid is selected from the group consisting of petroleum ether, kerosene and cyclohexanol.
Claim 6
Dependent Claim
11 words
The method of claim 1, further comprising siliconizing the solid spheroids.
Claim 7
Dependent Claim
16 words
The method of claim 5, further comprising grinding the siliconized solid spheroids to improve their spericity.
Claim 8
Dependent Claim
8 words
Spheroids obtained by the method of claim 1.
Claim 9
Dependent Claim
8 words
Spheroids obtained by the method of claim 5.
Claim 10
Dependent Claim
8 words
Spheroids obtained by the method of claim 6.
Claim 11
Independent Claim
114 words
A method of producing silicon carbide-carbon spheroids, said method comprising preparing a slip consisting essentially of an aqueous suspension of silicon carbide and carbon powders, an amount of at least one dispersant effective to prevent flocculation, and sodium alginate; introducing drops of the slip into an aqueous solution of an electrolyte; said electrolyte being present in an amount effective to flocculate the silicon carbide and carbon powders and form individual solid spheroids comprising a coherent mixture of silicon carbide and carbon, and said sodium alginate being present in an amount effective to increase the rigidity of the solid silicon carbide-carbon spheroids as they precipitate; and allowing the solid spheroids of increased rigidity to precipitate.
Claim 12
Independent Claim
114 words
A method of producing silicon carbide-carbon spheroids, said method comprising preparing a slip consisting essentially of an aqueous suspension of silicon carbide and carbon powders, an amount of at least one dispersant effective to prevent flocculation, and sodium alginate; introducing drops of the slip into an aqueous solution of an electrolyte; said electrolyte being present in an amount effective to flocculate the silicon carbide and carbon powders and form individual solid spheroids comprising a coherent mixture of silicon carbide and carbon, and said sodium alginate being present in an amount effective to increase the rigidity of the solid silicon carbide-carbon spheroids as they precipitate; and allowing the solid spheroids of increased rigidity to precipitate.
Claim 13
Dependent Claim
59 words
The method of claim 10, wherein the calcium salt present in the aqueous solution into which the drops are introduced is calcium chloride; and the sodium alginate is added to the aqueous suspension of silicon carbide and carbon powders and the dispersant in an amount effective to form substantially insoluble calcium alginate in the presence of the calcium chloride.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-11-16 | 1991-05-18 | 1991-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-16 | 1995-05-18 | 1995-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-16 | 1999-05-18 | 1999-11-17 | $7700.00 | Window Closed / Lapsed |