US4713279A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Fuji Electric Co Ltd
•
Filing: 1986-04-15
•
Granted: 1987-12-15
•
Expires: 2006-04-15
Abstract
Abstract A magnetic recording medium is disclosed comprising a non-magnetic base plate, a magnetic layer formed on said plate, a protective layer comprising silicon dioxide formed on said protective layer, and a lubricant layer comprising amorphous carbon formed on said protective layer. The magnetic recording medium is simple to manufacture and has good CSS resistance, sparing absorptivity and high corrosion resistance.
Inventors
- 👤 Norio Fujiwara
- 👤 Nobuyuki Takahashi
- 👤 Akihiro Otsuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:34
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/725; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/24364; Y10T428/24372; Y10T428/24413; Y10T428/24942; Y10T428/2495; Y10T428/24967; Y10T428/24975; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/30
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
39 words
A magnetic recording medium comprising a non-magnetic base plate, a magnetic layer formed on said plate, a protective layer comprising silicon dioxide formed on said magnetic layer, and a lubricant layer comprising amorphous carbon formed on said protective layer.
Claim 2
Dependent Claim
39 words
A magnetic recording medium comprising a non-magnetic base plate, a magnetic layer formed on said plate, a protective layer comprising silicon dioxide formed on said magnetic layer, and a lubricant layer comprising amorphous carbon formed on said protective layer.
Claim 3
Dependent Claim
15 words
The magnetic recording medium of claim 1, wherein the magnetic layer comprises a Co-based alloy.
Claim 4
Dependent Claim
18 words
The magnetic recording medium of claim 1, wherein the non-magnetic base plate is formed of an Al-Mg alloy.
Claim 5
Dependent Claim
22 words
The magnetic recording medium of claim 3, wherein the magnetic layer is a non-electrolytic Ni-P alloy plating applied onto the base plate.
Claim 6
Dependent Claim
17 words
The magnetic recording medium of claim 1, wherein the magnetic layer is made of a Co-P alloy.
Claim 7
Dependent Claim
20 words
The magnetic recording medium of claim 1, wherein the protective layer is between about 230 Å and 250 Å thick.
Claim 8
Dependent Claim
20 words
The magnetic recording medium of claim 1, wherein the lubricant layer is between about 260 Å and 265 Å thick.
Claim 9
Dependent Claim
15 words
The magnetic recording medium of claim 1, wherein the protective layer is applied by sputtering.
Claim 10
Dependent Claim
15 words
The magnetic recording medium of claim 1, wherein the lubricating layer is applied by sputtering.
Claim 11
Dependent Claim
24 words
The magnetic recording medium of claim 1, wherein the surface roughness of the base plate is about equal to or less than 0.01 μm.
Claim 12
Dependent Claim
22 words
The magnetic recording medium of claim 1, wherein the luricating layer is formed by presputtering argon gas, and then sputtering amorphous carbon.
Claim 13
Dependent Claim
18 words
The magnetic recording medium of claim 1, wherein the lubricating layer has a friction coefficient of about 0.25.
Claim 14
Dependent Claim
20 words
The magnetic recording medium of claim 1, wherein the magnetic layer is made of a γ-Fe 2 O 3 alloy.
References Cited (Backward Citations)
US4411963A
Cited
JPS5433521A
Cited
US4268369A
Cited
US4503125A
Cited
US4390562A
Cited
JPS60145524A
Cited
US4554217A
Cited
US4647494A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-12-14 | 1991-06-15 | 1991-12-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-12-14 | 1995-06-15 | 1995-12-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-12-14 | 1999-06-15 | 1999-12-15 | $7700.00 | Window Closed / Lapsed |