Patent US4909017B1 successfully refreshed from Google Patents.
Patent US2853407A successfully refreshed from Google Patents.
US2853407A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making magnetic recording media
Assignee: International Business Machines Corp
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Filing: 1957-12-20
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Granted: 1958-09-23
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Expires: 1977-12-20
Abstract
No abstract record available.
Inventors
- 👤 Russell V Rogers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:39
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
99 words
THE PROCESS OF TREATING A FERROUS BASE TO FORM THEREON A SMOOTH CONTINUOUS MAGNETIC SURFACE WHICH COMPRISES SURROUNDING SAID BASE WITH A POROUS REFRACTORY MATERIAL, PLACING SAID BASE WHILE SO SURROUNDED INTO A SEALED CHAMBER, HEATING SAID CHAMBER TO A TEMPERATURE AT WHICH THE BASE SURFACE CONVERTS TO A MAGNETIC OXIDE IN THE PRESENCE OF AN OXIDIZING MEDIUM, AND INTRODUCING STEAM INTO SAID CHAMBER AS IT IS BEING HEATED WITH THE STEAM PASSING THROUGH THE POROUS REFRACTORY MATERIAL TO SAID BASE PROVIDING THE OXIDIZING MEDIUM NECESSARY FOR THE CONVERSION OF THE SURFACE OF SAID BASE INTO A MAGNETIC OXIDE.
Claim 2
Dependent Claim
99 words
THE PROCESS OF TREATING A FERROUS BASE TO FORM THEREON A SMOOTH CONTINUOUS MAGNETIC SURFACE WHICH COMPRISES SURROUNDING SAID BASE WITH A POROUS REFRACTORY MATERIAL, PLACING SAID BASE WHILE SO SURROUNDED INTO A SEALED CHAMBER, HEATING SAID CHAMBER TO A TEMPERATURE AT WHICH THE BASE SURFACE CONVERTS TO A MAGNETIC OXIDE IN THE PRESENCE OF AN OXIDIZING MEDIUM, AND INTRODUCING STEAM INTO SAID CHAMBER AS IT IS BEING HEATED WITH THE STEAM PASSING THROUGH THE POROUS REFRACTORY MATERIAL TO SAID BASE PROVIDING THE OXIDIZING MEDIUM NECESSARY FOR THE CONVERSION OF THE SURFACE OF SAID BASE INTO A MAGNETIC OXIDE.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-09-22 | 1962-03-24 | 1962-09-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-09-22 | 1966-03-24 | 1966-09-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-09-22 | 1970-03-24 | 1970-09-23 | $7700.00 | Window Closed / Lapsed |