US4543341A
Expired / Lapsed
US
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Synthesis and processing of monosized oxide powders
Assignee: Massachusetts Institute of Technology
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Filing: 1983-12-23
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Granted: 1985-09-24
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Expires: 2003-12-23
Abstract
Abstract Uniform-size, high-purity, spherical oxide powders are formed by hydrolysis of alkoxide precursors in dilute alcoholic solutions. Under controlled conditions (concentrations of 0.03 to 0.2 M alkoxide and 0.2 to 1.5 M water, for example) oxide particles on the order of about 0.05 to 0.7 micron can be produced. Methods of doping such powders and forming sinterable compacts are also disclosed.
Inventors
- 👤 Eric A. Barringer
- 👤 M. Bruce Fegley, Jr.
- 👤 H. Kent Bowen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:15
CPC Classifications
C; C01; C01B; C01B13/00; C01B13/14; C01B13/32; B; B82; B82Y; B82Y30/00; C01G; C01G23/00; C01G23/04; C01G23/047; C01G23/053; C01G25/00; C01G25/02; C01G9/00; C01G9/02; C04; C04B; C04B35/00; C04B35/01; C04B35/453; C04B35/46; C04B35/48; C04B35/486; C04B35/622; C04B35/626; C01P; C01P2004/00; C01P2004/01; C01P2004/03; C01P2004/30; C01P2004/32; C01P2004/51; C01P2004/52; C01P2004/60; C01P2004/62; C01P2004/64; C01P2006/00; C01P2006/80
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
62 words
A method of forming generally spherical, sinterable metallic oxide metallic oxide powders with a narrow size distribution comprising: (a) under inert atmosphere hydrolyzing a dilute alcoholic solution of a metallic alkoxide wherein the solution ranges from about 0.2 to about 1.5 molar water and the concentration of the alkoxide ranges from about 0.03 to 0.2 molar alkoxide; and (b) collecting the precipitate.
Claim 2
Independent Claim
62 words
A method of forming generally spherical, sinterable metallic oxide metallic oxide powders with a narrow size distribution comprising: (a) under inert atmosphere hydrolyzing a dilute alcoholic solution of a metallic alkoxide wherein the solution ranges from about 0.2 to about 1.5 molar water and the concentration of the alkoxide ranges from about 0.03 to 0.2 molar alkoxide; and (b) collecting the precipitate.
Claim 3
Dependent Claim
24 words
The method of claim 1 wherein the alkoxide is chosen from the group of titanium alkoxides, zirconium alkoxides, zinc double alkoxide and mixtues thereof.
Claim 4
Dependent Claim
18 words
The method of claim 1 wherein the alkoxide is a titanium alkoxide and the resulting oxide is titania.
Claim 5
Dependent Claim
18 words
The method of claim 1 wherein the alkoxide is a zirconium alkoxide and the resulting oxide is zirconia.
Claim 6
Dependent Claim
19 words
The method of claim 1 wherein the alkoxide is a zinc alkoxide and the resulting oxide is zinc oxide.
Claim 7
Dependent Claim
23 words
The method of claim 1 wherein the hydrolyzing step further comprises cohydrolyzing an alkoxide of a suitable dopant to yield a doped powder.
Claim 8
Dependent Claim
24 words
The method of claim 1 wherein the hydrolyzing step further comprises co-precipitating a dopant from a soluble inorganic salt to yield a doped powder.
Claim 9
Independent Claim
95 words
A method of forming sinterable compacts which yield uniformly dense ceramic structures upon sintering, the method comprising: (a) dispersing particles of at least one metallic oxide in a solution having a low electrolyte concentration, the particles having generally spherical shapes, a narrow size distribution and a mean diameter ranging from about 0.05 microns to about 0.7 microns; (b) maintaining the pH of the solution sufficiently above or below the isoelectric point to avoid agglomeration of the particles in solution; and (c) forming the particles by sedimentation into an orderly packing arrangement in a desired shape.
Claim 10
Independent Claim
95 words
A method of forming sinterable compacts which yield uniformly dense ceramic structures upon sintering, the method comprising: (a) dispersing particles of at least one metallic oxide in a solution having a low electrolyte concentration, the particles having generally spherical shapes, a narrow size distribution and a mean diameter ranging from about 0.05 microns to about 0.7 microns; (b) maintaining the pH of the solution sufficiently above or below the isoelectric point to avoid agglomeration of the particles in solution; and (c) forming the particles by sedimentation into an orderly packing arrangement in a desired shape.
Claim 11
Independent Claim
81 words
A method of forming sinterable compacts which yield porous ceramic structures upon sintering, the method comprising: (a) dispersing particles of at least one metallic oxide in a solution, the particles having a spherical shape, a narrow size distribution, and a mean diameter ranging from about 0.05 microns to about 0.7 micron; (b) manipulating at least one parameter chosen from the group of electrolyte concentration and pH to permit controlled agglomeration; and (c) forming the particles by sedimentation into a desired shape.
Claim 12
Independent Claim
81 words
A method of forming sinterable compacts which yield porous ceramic structures upon sintering, the method comprising: (a) dispersing particles of at least one metallic oxide in a solution, the particles having a spherical shape, a narrow size distribution, and a mean diameter ranging from about 0.05 microns to about 0.7 micron; (b) manipulating at least one parameter chosen from the group of electrolyte concentration and pH to permit controlled agglomeration; and (c) forming the particles by sedimentation into a desired shape.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1988-09-23 | 1989-03-25 | 1989-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-23 | 1993-03-25 | 1993-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-23 | 1997-03-25 | 1997-09-24 | $7700.00 | Window Closed / Lapsed |