US5067979A
Expired / Lapsed
US
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Sintered bodies and production process thereof
Assignee: JFE Steel Corp
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Filing: 1990-07-06
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Granted: 1991-11-26
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Expires: 2010-07-06
Abstract
Abstract A process is provided for the production of a sintered body. The process includes the following consecutive steps: i) mixing and kneading one or more metal powders and/or one or more alloy powder with a binder into a compound, said metal and alloy powders having an average particle size not greater than 30 μm, ii) injection-molding the compound into a green body; iii) debinding the green body to form a debound body; and iv) subjecting the debound body to a first-stage sintering at 1,050°-1,250° C. in a reduced-pressure atmosphere and then to second-stage sintering at a temperature in a range of 1,100°-400° C. which is higher than that of the first-stage sintering. This process can provide sintered Ti bodies and sintered magnetic bodies of the Fe-Si type, which have a density ratio of at least 95%.
Inventors
- 👤 Yoshisato Kiyota
- 👤 Junichi Ohta
- 👤 Hiroshi Ohtsubo
- 👤 Shigeaki Takajo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:16
CPC Classifications
B; B22; B22F; B22F3/00; B22F3/22; B22F3/225; B22F3/10; B22F3/1003; B22F3/1007; B22F3/101; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/20; H01F1/22; A; A61; A61F; A61F2/00; A61F2/02; A61F2/30; A61F2/3094; A61F2002/30968; B22F2998/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
46 words
A sintered magnetic body of the Fe-Si type consisting essentially of 1.5-6.5 wt. % of Si, up to 0.5 wt./T of O, up to 0.03 wt. % of C, and the balance of Fe and imperative impurities and having a density ratio of at least 95%.
Claim 2
Dependent Claim
46 words
A sintered magnetic body of the Fe-Si type consisting essentially of 1.5-6.5 wt. % of Si, up to 0.5 wt./T of O, up to 0.03 wt. % of C, and the balance of Fe and imperative impurities and having a density ratio of at least 95%.
Claim 3
Dependent Claim
158 words
A process for the production of a sintered magnetic body of the Fe-Si type, which comprises the following steps: (i) mixing and kneading at least one powder selected from the group which consists of one or more Fe-Si alloy powders, an Fe powder and a Si powder with a binder into a compound, to give a final composition which comprises 1.5-6.5 wt. % of Si and the balance substantially of Fe, said alloy and metal powders having an average particle size of 3-25 μm; (ii) injection molding the compound into a green body; (iii) debinding the green body to form a debound body; and (iv) subjecting the debound body to a first stage sintering step at 1,050-1,250° C. in a reducing atmosphere or in a reduced-pressure atmosphere not higher than 0.1 Torr, and then subjecting the body to a second-stage sintering step at a temperature at least 50° C. higher than the temperature of the first-stage sintering step.
Claim 4
Dependent Claim
158 words
A process for the production of a sintered magnetic body of the Fe-Si type, which comprises the following steps: (i) mixing and kneading at least one powder selected from the group which consists of one or more Fe-Si alloy powders, an Fe powder and a Si powder with a binder into a compound, to give a final composition which comprises 1.5-6.5 wt. % of Si and the balance substantially of Fe, said alloy and metal powders having an average particle size of 3-25 μm; (ii) injection molding the compound into a green body; (iii) debinding the green body to form a debound body; and (iv) subjecting the debound body to a first stage sintering step at 1,050-1,250° C. in a reducing atmosphere or in a reduced-pressure atmosphere not higher than 0.1 Torr, and then subjecting the body to a second-stage sintering step at a temperature at least 50° C. higher than the temperature of the first-stage sintering step.
Claim 5
Dependent Claim
29 words
The process as claimed in claim 2, further comprising the step of adjusting the C/O molar ratio of the debound body to 0.5-3.0 before conducting the first-stage sintering step.
Claim 6
Dependent Claim
24 words
The process as claimed in claim 2, wherein the second-stage sintering step is conducted in an inert gas atmosphere of at least 30 atm.
Claim 7
Dependent Claim
21 words
The process as claimed in claim 4, wherein the alloy and metal powders have an average particle size of 10-25 μm.
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) | 1994-11-25 | 1995-05-27 | 1995-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-11-25 | 1999-05-27 | 1999-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-11-25 | 2003-05-27 | 2003-11-26 | $7700.00 | Window Closed / Lapsed |