Patent EP0069706A1 successfully refreshed from Google Patents.
US4938673A
Expired / Lapsed
US
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Isostatic pressing with microwave heating and method for same
Assignee: Individual
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Filing: 1989-01-17
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Granted: 1990-07-03
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Expires: 2009-01-17
Abstract
Abstract The invention includes an isostatic press supply of heat to a workpiece by microwave energy and a method for isostatically pressing a powdered ceramic or powdered metal material that is heated by microwave energy. The isostatic press includes a pressure vessel. A fluid medium is available for supply to the pressure vessel under pressure. The invention further includes a means for transmitting microwave energy into the pressure vessel. The method includes preparing a workpiece comprising a microwave coupler material. Desirably, the workpiece is a composition comprising a powdered coupler or semiconductor and a powdered insulator. The workpiece is immersed in an additional powdered insulator which is transparent to the microwave energy. The workpiece and immersing powdered insulator are contained in a closed, compressible container. The contained, immersed workpiece is then placed into a pressure vessel. Microwave energy is transmitted into the pressure vessel at a sufficient frequency to couple with the coupler. A fluid medium is supplied into the vessel under pressure either concurrently and/or before and/or after the transmission of microwave energy. The microwave energy couples with the coupler which causes the insulator of the workpiece to heat. The immersing insulator that surrounds the workpiece remains cool.
Inventors
- 👤 Donald J. Adrian
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:14
CPC Classifications
B; B30; B30B; B30B11/00; B30B11/001; B30B11/002; B22; B22F; B22F3/00; B22F3/12; B22F3/14; B22F3/15; B30B15/00; B30B15/34; C; C04; C04B; C04B35/00; C04B35/622; C04B35/64; C04B35/645; C04B35/6455
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
87 words
A method for isostatically pressing comprising: preparing a workpiece, said workpiece being a composition comprising a powdered coupler and a first powdered insulator; immersing said workpiece in a second powdered insulator, said second powdered insulator being in a compressible container; placing said contained, immersed workpiece into a pressure vessel; transmitting microwave energy into said pressure vessel at a sufficient frequency for a sufficient time to elevate said workpiece to a desired temperature; and densifying said workpiece with a fluid medium supplied into said pressure vessel under pressure.
Claim 2
Independent Claim
87 words
A method for isostatically pressing comprising: preparing a workpiece, said workpiece being a composition comprising a powdered coupler and a first powdered insulator; immersing said workpiece in a second powdered insulator, said second powdered insulator being in a compressible container; placing said contained, immersed workpiece into a pressure vessel; transmitting microwave energy into said pressure vessel at a sufficient frequency for a sufficient time to elevate said workpiece to a desired temperature; and densifying said workpiece with a fluid medium supplied into said pressure vessel under pressure.
Claim 3
Dependent Claim
19 words
The method of claim 1, wherein said transmitting of microwave energy and said densifying of said workpiece occur simultaneously.
Claim 4
Dependent Claim
20 words
The method of claim 1, wherein said first powdered insulator and said second powdered insulator are of identical chemical composition.
Claim 5
Dependent Claim
17 words
The method of claim 1, wherein said workpiece is compacted before immersing into said second powdered insulator.
Claim 6
Dependent Claim
12 words
The method of claim 1, wherein said powdered coupler is semiconductor whiskers.
Claim 7
Dependent Claim
13 words
The method of claim 5, wherein said semiconductor whiskers are silicon carbide whiskers.
Claim 8
Dependent Claim
23 words
The method of claim 6, wherein said silicon carbide whiskers are in a concentration of from about 0.5 percent to about 45 percent.
Claim 9
Independent Claim
61 words
A method for isostatically pressing comprising: preparing a green body, said green body being a composition comprising a powdered coupler and a first powdered insulator; immersing said green body in a second powdered insulator; elevating the temperature of said green body by microwave energy; and pressing by mechanical means said green body, said second powdered insulator being a pressure transfer medium.
Claim 10
Independent Claim
61 words
A method for isostatically pressing comprising: preparing a green body, said green body being a composition comprising a powdered coupler and a first powdered insulator; immersing said green body in a second powdered insulator; elevating the temperature of said green body by microwave energy; and pressing by mechanical means said green body, said second powdered insulator being a pressure transfer medium.
Claim 11
Dependent Claim
21 words
The method of claim 8, wherein said transmitting of microwave energy and said pressing of said pressure transfer medium occur simultaneously.
Claim 12
Dependent Claim
20 words
The method of claim 8, wherein said first powdered insulator and said second powdered insulator are of identical chemical composition.
Claim 13
Dependent Claim
13 words
The method of claim 10, wherein said semiconductor whiskers are silicon carbide whiskers.
Claim 14
Dependent Claim
23 words
The method of claim 11, wherein said silicon carbide whiskers are in a concentration of from about 5 percent to about 10 percent.
Claim 15
Independent Claim
59 words
A method for isostatically pressing comprising: preparing a workpiece, said workpiece comprising a coupler; placing said workpiece into a pressure vessel; transmitting microwave energy into said pressure vessel at a sufficient frequency for a sufficient time to elevate said workpiece to a desired temperature; and densifying said workpiece with a fluid medium supplied into said pressure vessel under pressure.
Claim 16
Independent Claim
59 words
A method for isostatically pressing comprising: preparing a workpiece, said workpiece comprising a coupler; placing said workpiece into a pressure vessel; transmitting microwave energy into said pressure vessel at a sufficient frequency for a sufficient time to elevate said workpiece to a desired temperature; and densifying said workpiece with a fluid medium supplied into said pressure vessel under pressure.
Claim 17
Dependent Claim
18 words
The method of claim 13, wherein said transmitting of microwave energy and said densifying said workpiece occur simultaneously.
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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) | 1993-07-02 | 1994-01-01 | 1994-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-02 | 1998-01-01 | 1998-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-02 | 2002-01-01 | 2002-07-03 | $7700.00 | Window Closed / Lapsed |