US3702273A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Etching compositions and method for etching cu and ni based metals at a uniform rate
Assignee: International Business Machines Corp
•
Filing: 1970-12-21
•
Granted: 1972-11-07
•
Expires: 1990-12-21
Abstract
Abstract COMPOSITE STRUCTURES OF NICKEL BASED METALS AND COPPER BASED METALS ARE UTILIZED FOR EXAMPLE, IN MAGNETIC READ/WRITE TRANSDUCERS. THE SURFACES OF SUCH STRUCTURES ARE NORMALLY FINISHED BY GRINDING. HOWEVER, GRINDING SOMETIMES TENDS TO SMEAR THE DIFFERENT METALS OVER ONE ANOTHER, THUS, INTERFERING WITH THEIR DESIRED ELECTRICAL AND MAGNETIC CHARACTERICS. IN THE PRESENT INVENTION, SMEARED DISSIMILAR METALS ARE REMOVED AT A SUBSTANTIALLY UNIFORM RATE BY ETCHING WITH COMPOSITIONS INCLUDING NITRIC ACID, SULFURIC ACID, AND ACETIC ACID IN RELATIVE PERCENTAGES BY VOLUME LYING WITHIN THE AREA DEFINED APPROXIMATELY IN THE ACCOMPANYING DIAGRAM BY THE SOLID LINES AB, BC, CD, DE, AND EA.
Inventors
- 👤 Harold Kenneth Johnston
- 👤 Thecdore Lowell Larson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 02:22
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/16; G; G11; G11B; G11B5/00; G11B5/127; G11B5/187; G11B5/1871
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-11-07 | 1976-05-08 | 1976-11-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-07 | 1980-05-08 | 1980-11-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-07 | 1984-05-08 | 1984-11-07 | $7700.00 | Window Closed / Lapsed |