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US4806429A
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Plate-like barium ferrite particles suitable for use in magnetic recording and process for producing the same
Assignee: Toda Kogyo Corp
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Filing: 1987-01-29
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Granted: 1989-02-21
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Expires: 2007-01-29
Abstract
Abstract Disclosed herein are plate-like barium ferrite particles with a solid solution of zinc on the surface thereof, which have an average particle diameter of 0.05 to 0.3 μm, a coercive force of 300 to 1,500 Oe and a magnetization of not less than 55 emu/g in magnetic field of 10 KOe, and which are represented by the following formula (I): BaO·n[(Fe.sub.1-2x Co.sub.x Ti.sub.x).sub.2 O.sub.3 ](I) wherein x is 0 to 0.1 and n is from 4 to 11, the molar ratio of Ti to Co being 1, and a process for producing the plate-like barium ferrite particles.
Inventors
- 👤 Norimichi Nagai
- 👤 Akihiko Hirayama
- 👤 Norio Sugita
- 👤 Masao Kiyama
- 👤 Toshio Takada
- 👤 Katsunori Fujimoto
- 👤 Yasutaka Ota
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:54
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/10; G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; G11B5/70678; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
84 words
Plate-like barium ferrite particles with a solid solution of zinc on the surface thereof, which have an average particle diameter of 0.05 to 0.3 μm, a coercive force of 300 to 1,500 Oe and a magnetization of not less than 55 emu/g in magnetic field of 10 KOe, and which are represented by the following formula (1) BaO·n[(Fe.sub.1-2x Co.sub.x Ti.sub.x).sub.2 O.sub.3 ](I) wherein x is 0 to 0.1 and n is from 4 to 11, the molar ratio of Ti to Co being 1.
Claim 2
Dependent Claim
84 words
Plate-like barium ferrite particles with a solid solution of zinc on the surface thereof, which have an average particle diameter of 0.05 to 0.3 μm, a coercive force of 300 to 1,500 Oe and a magnetization of not less than 55 emu/g in magnetic field of 10 KOe, and which are represented by the following formula (1) BaO·n[(Fe.sub.1-2x Co.sub.x Ti.sub.x).sub.2 O.sub.3 ](I) wherein x is 0 to 0.1 and n is from 4 to 11, the molar ratio of Ti to Co being 1.
Claim 3
Dependent Claim
44 words
Plate-like barium ferrite particles according to claim 1, wherein the quantity of a solid solution of zinc with respect to the plate-like barium ferrite particles with the solid solution of zinc on the surface thereof is 0.2 to 5.0 wt % (calculated as Zn).
Claim 4
Dependent Claim
17 words
Plate-like barium ferrite particles according to claim 1, wherein a magnetization is not less than 57 emu/g.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-21 | 1992-08-22 | 1993-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-21 | 1996-08-22 | 1997-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-21 | 2000-08-22 | 2001-02-21 | $7700.00 | Window Closed / Lapsed |