Patent US4643915A successfully refreshed from Google Patents.
US4643915A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing magnetic recording medium
Assignee: Fujifilm Holdings Corp
•
Filing: 1985-06-27
•
Granted: 1987-02-17
•
Expires: 2005-06-27
Abstract
Abstract A magnetic recording medium provided with a protective layer having excellent corrosion resistance and good adhesion is provided by a process which comprises forming a thin magnetic metal film on a nonmagnetic substrate by an oblique vapor deposition technique in a vacuum vessel, blowing an oxidizing gas against the surface of the thin magnetic metal film in the same vacuum vessel as used in the formation of the thin magnetic metal film, and thereafter forming a thin nonmagnetic metal film on the thin magnetic metal film.
Inventors
- 👤 Yoshihiro Arai
- 👤 Ryuji Shirahata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:48
CPC Classifications
C; C23; C23C; C23C14/00; C23C14/02; C23C14/024; C23C14/025; C23C14/06; C23C14/14; C23C14/20; G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/84; G11B5/85
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
83 words
A process for producing a magnetic recording medium, which comprises forming a thin magnetic metal film on a nonmagnetic substrate by an oblique vapor deposition technique in a vacuum vessel, blowing an oxidizing gas against the surface of the thin magnetic metal film in the same vacuum vessel as used in the formation of the thin magnetic metal film, and thereafter forming as thin nonmagnetic metal film having a thickness of about 0.005 micrometer to 0.1 micrometer on the thin magnetic metal film.
Claim 2
Dependent Claim
83 words
A process for producing a magnetic recording medium, which comprises forming a thin magnetic metal film on a nonmagnetic substrate by an oblique vapor deposition technique in a vacuum vessel, blowing an oxidizing gas against the surface of the thin magnetic metal film in the same vacuum vessel as used in the formation of the thin magnetic metal film, and thereafter forming as thin nonmagnetic metal film having a thickness of about 0.005 micrometer to 0.1 micrometer on the thin magnetic metal film.
Claim 3
Dependent Claim
31 words
The process of claim 1, wherein the thin nonmagnetic metal film is of at least one nonmagnetic metal selected from the group consisting of Cr, Ti, Sn, Cu, Al, and Ta.
Claim 4
Dependent Claim
28 words
The process of claim 2, wherein the thin nonmagnetic metal film is of at least one nonmagnetic metal selected from the group consisting of Cr, Ti and Sn.
Claim 5
Dependent Claim
20 words
The process of claim 1, wherein the thin magnetic film has a thickness of about 0.02 micrometer to 5.0 micrometers.
Claim 6
Dependent Claim
20 words
The process of claim 1, wherein the thin magnetic film has a thickness of about 0.05 micrometer to 2.0 micrometers.
Claim 7
Dependent Claim
21 words
The process of claim 5, wherein the thin nonmagnetic metal film has a thickness of about 0.005 micrometer to 0.02 micrometer.
References Cited (Backward Citations)
JPS54140998A
Cited
US4477489A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-02-16 | 1990-08-18 | 1991-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-16 | 1994-08-18 | 1995-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-16 | 1998-08-18 | 1999-02-17 | $7700.00 | Window Closed / Lapsed |