US4154875A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for manufacturing a magnetic record member
Assignee: NEC Corp
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Filing: 1977-10-25
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Granted: 1979-05-15
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Expires: 1997-10-25
Abstract
Abstract The thin film magnetic medium of a magnetic disc, and the read/record head employed with the disc are both protected from abusive use and physical damage as well as chemical damage (including damage due to heat and/or humidity) by a polysilicate layer, formed upon the magnetic medium. Inexpensive methods of forming the protective film (which methods lend themselves to mass production) are described. These methods are a small fraction of the cost of present day techniques.
Inventors
- 👤 Masahiro Yanagisawa
- 👤 Yoji Suganuma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 03:47
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/725; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
130 words
A process for manufacturing a magnetic record member comprising the steps of: forming a film of a non-magnetic alloy on the surface of an alloy disc; polishing the non-magnetic alloy layer thus formed to form a mirror finish surface; forming a magnetic metal thin film medium on the polished surface of said non-magnetic alloy layer; applying a solution of tetrahydroxy silane derived by hydrolysis of tetraalkoxy silane onto said thin film medium; baking the disc having the thus prepared composite layers at a temperature greater than one hundred degrees centigrade in a manner so that variation in the magnetic property of the thin film medium will not adversely affect the recording and reproducing characteristics of the magnetic record member whereby a polysilicate film is formed on the thin film medium.
Claim 2
Dependent Claim
130 words
A process for manufacturing a magnetic record member comprising the steps of: forming a film of a non-magnetic alloy on the surface of an alloy disc; polishing the non-magnetic alloy layer thus formed to form a mirror finish surface; forming a magnetic metal thin film medium on the polished surface of said non-magnetic alloy layer; applying a solution of tetrahydroxy silane derived by hydrolysis of tetraalkoxy silane onto said thin film medium; baking the disc having the thus prepared composite layers at a temperature greater than one hundred degrees centigrade in a manner so that variation in the magnetic property of the thin film medium will not adversely affect the recording and reproducing characteristics of the magnetic record member whereby a polysilicate film is formed on the thin film medium.
Claim 3
Dependent Claim
110 words
A manufacturing process for a magnetic record member comprising the steps of: forming a magnetic metal thin film medium directly on the surface of an alloy disc which has been polished to a mirror surface; applying a solution of a tetrahydroxy silane derived by hydrolysis of tetraalkoxy silane onto said thin film medium; baking the dish having the thus prepared layer at a temperature greater than one hundred degrees centigrade in such a manner that variation in the magnetic property of the thin film medium will not adversely affect the recording and reproducing characteristics of the magnetic record member whereby a polysilicate film is formed on the thin film medium.
Claim 4
Dependent Claim
110 words
A manufacturing process for a magnetic record member comprising the steps of: forming a magnetic metal thin film medium directly on the surface of an alloy disc which has been polished to a mirror surface; applying a solution of a tetrahydroxy silane derived by hydrolysis of tetraalkoxy silane onto said thin film medium; baking the dish having the thus prepared layer at a temperature greater than one hundred degrees centigrade in such a manner that variation in the magnetic property of the thin film medium will not adversely affect the recording and reproducing characteristics of the magnetic record member whereby a polysilicate film is formed on the thin film medium.
Claim 5
Dependent Claim
31 words
The process of claim 1 wherein the temperature level during baking is not permitted to reach a level which would otherwise remove silanol radicals present in the polysilicate layer if exceeded.
Claim 6
Dependent Claim
31 words
The process of claim 2 wherein the temperature level during baking is not permitted to reach a level which would otherwise remove silanol radicals present in the polysilicate layer if exceeded.
Claim 7
Dependent Claim
16 words
The process of claim 3 wherein said upper level is of the order of 750° C.
Claim 8
Dependent Claim
15 words
The process of claim 4 wherein said upper level is of the order of 750°.
References Cited (Backward Citations)
US4069360A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-05-14 | 1982-11-13 | 1983-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-05-14 | 1986-11-13 | 1987-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-05-14 | 1990-11-13 | 1991-05-15 | $7700.00 | Window Closed / Lapsed |