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US4923512A
Expired / Lapsed
US
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Cobalt-bound tungsten carbide metal matrix composites and cutting tools formed therefrom
Assignee: Dow Chemical Co
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Filing: 1989-04-07
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Granted: 1990-05-08
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Expires: 2009-04-07
Abstract
Abstract Cobalt-bound tungsten carbide metal matrix composites having a unique microstructure are produced by consolidating partially sintered greenware under high pressures, e.g., 120,000 psi, at temperatures less than those used for conventional liquid phase sintering in a relatively short time, e.g., from less than one minute to less than about one hour. The composites have a binder phase which contains less than about 80 weight percent of the tungsten found in a composite prepared from the same or similar compositions via liquid phase sintering. These composites provide cutting tools with both toughness and wear resistance which exceed that of cutting tools made from the same or similar compositions via liquid phase sintering.
Inventors
- 👤 Ed E. Timm
- 👤 Douglas B. Schwarz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:35
CPC Classifications
B; B22; B22F; B22F3/00; B22F3/12; B22F3/14; B22F3/15; B22F3/156; C; C22; C22C; C22C29/00; C22C29/02; C22C29/06; C22C29/08; B22F2998/00; B22F2998/10
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
151 words
A substantially fully dense article of manufacture suitable for use in cutting tool applications, said article being formed from a powdered composition comprising tungsten carbide in an amount of from about 82 to about 99 percent by weight of composition and cobalt in an amount of from about 1 to about 18 percent by weight of composition and having a unique microstructure, the microstructure comprising tungsten carbide grains having a mean grain size of less than about five microns, and a binder phase, the binder phase being substantially free of graphite and complex, intermetallic carbides and comprising, tungsten, cobalt and carbon, the tungsten in the binder phase being present in an amount of less than about eighty percent of that present in the binder of an article prepared by liquid phase sintering the same powdered composition at a temperature sufficient to provide substantially complete densification in the absence of external pressure.
Claim 2
Dependent Claim
151 words
A substantially fully dense article of manufacture suitable for use in cutting tool applications, said article being formed from a powdered composition comprising tungsten carbide in an amount of from about 82 to about 99 percent by weight of composition and cobalt in an amount of from about 1 to about 18 percent by weight of composition and having a unique microstructure, the microstructure comprising tungsten carbide grains having a mean grain size of less than about five microns, and a binder phase, the binder phase being substantially free of graphite and complex, intermetallic carbides and comprising, tungsten, cobalt and carbon, the tungsten in the binder phase being present in an amount of less than about eighty percent of that present in the binder of an article prepared by liquid phase sintering the same powdered composition at a temperature sufficient to provide substantially complete densification in the absence of external pressure.
Claim 3
Dependent Claim
17 words
The article of claim 1 wherein the binder phase further comprises at least one grain growth inhibitor.
Claim 4
Dependent Claim
24 words
The article of claim 2 wherein the amount of grain growth inhibitor is between and about 0.5 percent by weight of the powdered composition.
Claim 5
Dependent Claim
34 words
The article of claim 2 wherein the grain growth inhibitor is selected from the group consisting of vanadium carbide, molybdenum carbide, cesium carbide, niobium carbide, tantalum carbide, titanium carbide, zirconium/hafnium carbide and tantalum(niobium) carbide.
Claim 6
Dependent Claim
44 words
The article of claim 1 wherein the powdered composition comprises tungsten carbide in an amount of from about 85 to about 99 percent by weight of composition and cobalt in an amount of from about 1 to about 15 percent by weight of composition.
Claim 7
Dependent Claim
44 words
The article of claim 1 wherein the powdered composition comprises tungsten carbide in an amount of from about 88 to about 99 percent by weight of composition and cobalt in an amount of from about 1 to about 12 percent by weight of composition.
Claim 8
Dependent Claim
44 words
The article of claim 1 wherein the powdered composition comprises tungsten carbide in an amount of from about 94 to about 99 percent by weight of composition and cobalt in an amount of from about 1 to about 6 percent by weight of composition.
Claim 9
Dependent Claim
21 words
The article of claim 1 wherein the unique microstructure is attained by consolidation of the powdered composition via rapid omnidirectional compaction.
Claim 10
Dependent Claim
21 words
The article of claim 1 wherein the unique microstructure is attained by consolidation of the powdered composition via hot isostatic pressing.
Claim 11
Dependent Claim
34 words
The article of claim 8 wherein the powdered composition is formed into greenware which is partially sintered in a reactive gaseous atmosphere or under reduced pressure in an inert gaseous atmosphere prior to consolidation.
Claim 12
Dependent Claim
21 words
The article of claim 1 wherein the tungsten carbide grains have a mean grain size of less than about 2.5 microns.
Claim 13
Dependent Claim
21 words
The article of claim 1 wherein the tungsten carbide grains have a mean grain size of less than about one micron.
References Cited (Backward Citations)
US4341557A
Cited
US4610931A
Cited
US4428906A
Cited
US4630092A
Cited
US4753678A
Cited
US4649084A
Cited
US4656002A
Cited
US4828584A
Cited
US4744943A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-05-07 | 1993-11-06 | 1994-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-07 | 1997-11-06 | 1998-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-07 | 2001-11-06 | 2002-05-08 | $7700.00 | Window Closed / Lapsed |