US4344904A
Expired / Lapsed
US
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Sintering method of zirconia
Assignee: Sumitomo Chemical Co Ltd
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Filing: 1980-09-25
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Granted: 1982-08-17
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Expires: 2000-09-25
Abstract
Abstract A method is provided for producing a sintered zirconia article excellent in thermal shock resistance and high in sintered density. The method comprises mixing zirconia powder as the starting material and a stabilizing agent with a definite amount of partially stabilized zirconia powder, shaping and sintering the mixture, and heat treating it under specific temperature conditions.
Inventors
- 👤 Koichi Yamada
- 👤 Yasuo Shinya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:55
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/406; G01N27/407; G01N27/4073; C; C04; C04B; C04B35/00; C04B35/01; C04B35/48; C04B35/486; H; H01; H01M; H01M8/00; H01M8/10; H01M8/12; H01M8/124; H01M8/1246; H01M8/1253; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/50; Y02P; Y02P70/00; Y02P70/50
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
132 words
A method of producing a sintered zirconia article, comprising the steps of mixing 10-50% by weight of a partially stabilized zirconia powder obtained by adding a stabilizing agent to a zirconia powder and admixing, sintering the admixture and pulverizing the sintered admixture, and 90-50% by weight of a zirconia powder and a stabilizing agent; shaping the resulting mixture, sintering the shaped article and then heat treating the sintered article at a temperature of from 1200° to 1500° C., thereby to obtain a sintered zirconia article composed of a cubic phase crystal which has a crystalline structure of not more than 70% by weight and which is made up of 5-40% by weight of particles having a diameter range of 1-30μ and 95-60% by weight of particles having a diameter range of 30-300μ.
Claim 2
Independent Claim
132 words
A method of producing a sintered zirconia article, comprising the steps of mixing 10-50% by weight of a partially stabilized zirconia powder obtained by adding a stabilizing agent to a zirconia powder and admixing, sintering the admixture and pulverizing the sintered admixture, and 90-50% by weight of a zirconia powder and a stabilizing agent; shaping the resulting mixture, sintering the shaped article and then heat treating the sintered article at a temperature of from 1200° to 1500° C., thereby to obtain a sintered zirconia article composed of a cubic phase crystal which has a crystalline structure of not more than 70% by weight and which is made up of 5-40% by weight of particles having a diameter range of 1-30μ and 95-60% by weight of particles having a diameter range of 30-300μ.
Claim 3
Dependent Claim
27 words
A method according to claim 1 wherein the stabilizing agent is one member selected from the group consisting of CaO, MgO and Y 2 O 3 .
Claim 4
Dependent Claim
28 words
A method according to claim 1 wherein the stabilizing agent is added to the starting material zirconia powder in an amount of not more than 15 mol %.
Claim 5
Dependent Claim
30 words
A method according to claim 1 wherein the starting zirconia powder material, stabilizing agents and partially stabilized zirconia powder is made up of particles having diameters not larger than 20μ.
Claim 6
Dependent Claim
29 words
A method according to claim 1 wherein the sintering takes place at a temperature of from 1500° to 1900° C. and for a period of 0.5 to 30 hours.
Claim 7
Dependent Claim
21 words
A method according to claim 1 wherein the heat treatment is carried out for a period of 1 to 30 hours.
Claim 8
Dependent Claim
22 words
A method according to claim 1 wherein the sintered article is composed of a 10-50% by weight of cubic phase crystalline structure.
References Cited (Backward Citations)
US3175919A
Cited
US4205051A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-08-16 | 1986-02-15 | 1986-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-08-16 | 1990-02-15 | 1990-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-08-16 | 1994-02-15 | 1994-08-17 | $7700.00 | Window Closed / Lapsed |