Patent US4835640A successfully refreshed from Google Patents.
US4835640A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic head having a stabilized zirconia slider
Assignee: Proterial Ltd
•
Filing: 1987-11-19
•
Granted: 1989-05-30
•
Expires: 2007-11-19
Abstract
Abstract A magnetic recording device comprises a magnetic disk having a magnetic recording layer formed on a substrate, a slider, a magnetic core attached to the slider, and a magnetic head adapted to be brought into contact with and separated from the surface of the magnetic disk. In this magnetic recording device, the magnetic recording layer of the magnetic disk is made of a Co-based alloy and the slider of the magnetic head has stabilized zirconia as the main phase thereof.
Inventors
- 👤 Juro Endo
- 👤 Shiro Murakami
- 👤 Yukiharu Takada
- 👤 Yoshiharu Koike
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:02
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/10; G11B5/62; G11B5/64
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
72 words
A magnetic head comprising a slider portion and a magnetic core attached to the slider portion, the slider portion consisting essentially of zirconia and 5 to 20 mol % of a stabilizer so that the zirconia has a stabilized main phase having cubic cyrstal grains at a temperature below about 1200 deg. C. and the diameter of the cubic grains of the main phase of the zirconia being less than 12 μm.
Claim 2
Dependent Claim
72 words
A magnetic head comprising a slider portion and a magnetic core attached to the slider portion, the slider portion consisting essentially of zirconia and 5 to 20 mol % of a stabilizer so that the zirconia has a stabilized main phase having cubic cyrstal grains at a temperature below about 1200 deg. C. and the diameter of the cubic grains of the main phase of the zirconia being less than 12 μm.
Claim 3
Dependent Claim
52 words
The magnetic head as set forth in claim 1, wherein fine particles of at least one compound selected from the group consisting of the carbides of the elements of Groups IVa, Va and VIa in the periodic Table of Elements and alumina are dispersed in the stabilized zirconia phase of the slider.
Claim 4
Dependent Claim
45 words
The magnetic head as set forth in claim 2, wherein the amount of the carbide particle is in the range of about 0.5 to 30 vol. % and the amount of the alumina particles is in the range of about 0.5 to 30 vol %.
Claim 5
Dependent Claim
45 words
The magnetic head as set forth in claim 2, wherein the amount of the carbide particles is in the range of about 1 to 10 vol % and the amount of the alumina particles is in the range of about 1 to 10 vol %.
Claim 6
Dependent Claim
27 words
The magnetic head as set forth in claim 1, wherein the stabilizer is selected from the group consisting of Y 2 O 3 , MgO and CaO.
Claim 7
Dependent Claim
29 words
The magnetic head as set forth in claim 1, wherein the concentration of the stabilizer in the stabilized main phase of zirconia is about 5 to 10 mol %.
Claim 8
Dependent Claim
32 words
The magnetic head as set forth in claim 1, wherein the stabilized zirconia phase of the slider portion contains Y 2 O 3 in a concentration of 5 to 10 mol %.
Claim 9
Dependent Claim
27 words
The magnetic head as in claim 1 wherein the diameters of the cubic grains of the main phase of the zirconia are less than about 10 μm.
References Cited (Backward Citations)
US3823416A
Cited
US4411963A
Cited
US4251841A
Cited
US4503125A
Cited
US4582812A
Cited
US4430440A
Cited
JPS58121179A
Cited
JPS597823A
Cited
JPS5972307A
Cited
US4559572A
Cited
US4598052A
Cited
US4709284A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-05-29 | 1992-11-28 | 1993-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-29 | 1996-11-28 | 1997-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-29 | 2000-11-28 | 2001-05-30 | $7700.00 | Window Closed / Lapsed |