US4769351A
Expired / Lapsed
US
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Hydrothermal process for preparing zirconia-alumina base ultra-fine powders of high purity
Assignee: SHIGEYUKI SOUMIYA
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Filing: 1987-05-04
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Granted: 1988-09-06
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Expires: 2007-05-04
Abstract
Abstract A process for preparing a zirconia-alumina base composite ultra-fine powder is described, including the steps of: mixing an aluminum salt or an alumina hydrate with an aqueous zirconium oxychloride solution, with or without metal salt acting as a stabilizer; mixing urea or a substance capable of generating ammonia by hydrolysis with the resulting mixture; and allowing the mixture to react at a temperature of 140° to 300° C. and a pressure of 4 to 150 kg/cm 2 in a high-temperature and -pressure vessel. The reaction product is further dried, calcined and crushed to obtain an ultra-fine powder.
Inventors
- 👤 Shigeyuki Soumiya
- 👤 Masahiro Yoshimura
- 👤 Zenjiro Nakai
- 👤 Kazumitsu Hishinuma
- 👤 Takao Kumaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:32
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/626; C04B35/62605; B; B82; B82Y; B82Y30/00; C01; C01F; C01F7/00; C01F7/02; C01F7/34; C01G; C01G25/00; C04B35/01; C04B35/10; C04B35/111; C04B35/117; C04B35/119; C04B35/48; C04B35/486; C04B35/488; C04B35/4885; C01P; C01P2002/00; C01P2002/70; C01P2002/72; C01P2002/80; C01P2002/88; C01P2004/00; C01P2004/60; C01P2004/64; C04B2235/00; C04B2235/02; C04B2235/30; C04B2235/32; C04B2235/3217; C04B2235/3218; C04B2235/322; C04B2235/44; C04B2235/444; C04B2235/70; C04B2235/74; C04B2235/76; C04B2235/762; C04B2235/765; C04B2235/77; C04B2235/96; Y; Y10; Y10S; Y10S977/00; Y10S977/70; Y10S977/773; Y10S977/775; Y10S977/776; Y10S977/832; Y10S977/835; Y10S977/84; Y10S977/895; Y10S977/896; Y10S977/90
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
100 words
A process for preparing a zirconia-alumina base composite ultra-fine powder, comprising the steps of: (a) mixing an alumina matrix, selected from the group comprising an aluminum salt and an alumina hydrate, with an aqueous zirconium oxychloride solution; (b) adding a metal salt as a stabilizer; (c) adding a substance capable of generating ammonia by hydrolysis to the resulting mixture; and (d) allowing the mixture to react in a high temperature, high pressure vessel at a temperature of 200° to 220° C. and a pressure of 60-75 kg/cm 2 from between 5 to 10 hours to form a homogeneous reaction product.
Claim 2
Dependent Claim
100 words
A process for preparing a zirconia-alumina base composite ultra-fine powder, comprising the steps of: (a) mixing an alumina matrix, selected from the group comprising an aluminum salt and an alumina hydrate, with an aqueous zirconium oxychloride solution; (b) adding a metal salt as a stabilizer; (c) adding a substance capable of generating ammonia by hydrolysis to the resulting mixture; and (d) allowing the mixture to react in a high temperature, high pressure vessel at a temperature of 200° to 220° C. and a pressure of 60-75 kg/cm 2 from between 5 to 10 hours to form a homogeneous reaction product.
Claim 3
Dependent Claim
28 words
The process as recited in claim 1, further comprising the steps of: (d) drying the reaction product; (e) calcinating the reaction product; and (f) crushing the reaction product.
Claim 4
Dependent Claim
18 words
The process as recited in claim 1, wherein the substance capable of producing ammonia by hydrolysis is urea.
Claim 5
Dependent Claim
35 words
The product as recited in claim 1, wherein the aluminum salt is aluminum chloride, the alumina hydrate is selected from the group comprising boehmite and gibbsite, and the substance capable of generating ammonia is hexamethylenediamine.
Claim 6
Dependent Claim
35 words
The process as recited in claim 2, wherein the aluminum salt is aluminum chloride, the alumina hydrate is selected from the group comprising boehmite and gibbsite, and the substance capable of generating ammonia is hexamethylenediamine.
Claim 7
Dependent Claim
14 words
The process as recited in claim 1, wherein step (c) occurs in an autoclave.
Claim 8
Dependent Claim
14 words
The process as recited in claim 2, wherein step (c) occurs in an autoclave.
Claim 9
Dependent Claim
31 words
The process as recited in claim 2, wherein zirconia in the reaction product is in the range of 20-82% and alumina in the reaction product is in the range of 18-80%.
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) | 1991-09-06 | 1992-03-07 | 1992-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-06 | 1996-03-07 | 1996-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-06 | 2000-03-07 | 2000-09-06 | $7700.00 | Window Closed / Lapsed |