US2861906A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Metal treatment
Assignee: ZF Active Safety US Inc
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Filing: 1956-10-15
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Granted: 1958-11-25
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Expires: 1976-10-15
Abstract
No abstract record available.
Inventors
- 👤 Ludwig K Schuster
- 👤 Alfonso L Baldi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:06
CPC Classifications
C; C23; C23C; C23C22/00; C23C22/73
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
110 words
IN A METHOD OF COATING CORRODIBLE FERROUS METAL BY FIRST ETCHING THE METAL SURFACE IN AQUEOUS NITRIC ACID HAVING A CONCENTRATION OF FROM 1 TO 20% BY WEIGHT FOR A PERIOD OF FROM 2 TO 70 SECONDS TO A TEMPERATURE OF 60 TO 150*F., AND THEN APPLYING TO THE ETCHED SURFACE A FILM OF AN IN SITU DRIED AQUEOUS SOLUTION OF PARTIALLY REDUCED CHROMIC ACID, AT LEAST ABOUT HALF BUT LESS THAN ALL THE CHROMIC ACID IN THE FILM BEING REDUCED, THE IMPROVEMENT BY WHICH THE ETCHING IS PRECEDED BY A STEP IN WHICH THE METAL SURFACE IS SUBJECTED TO AN ACTIVATION TREATMENT TO MINIMIZE PASSIVATION BY THE NITRIC ACID.
Claim 2
Dependent Claim
110 words
IN A METHOD OF COATING CORRODIBLE FERROUS METAL BY FIRST ETCHING THE METAL SURFACE IN AQUEOUS NITRIC ACID HAVING A CONCENTRATION OF FROM 1 TO 20% BY WEIGHT FOR A PERIOD OF FROM 2 TO 70 SECONDS TO A TEMPERATURE OF 60 TO 150*F., AND THEN APPLYING TO THE ETCHED SURFACE A FILM OF AN IN SITU DRIED AQUEOUS SOLUTION OF PARTIALLY REDUCED CHROMIC ACID, AT LEAST ABOUT HALF BUT LESS THAN ALL THE CHROMIC ACID IN THE FILM BEING REDUCED, THE IMPROVEMENT BY WHICH THE ETCHING IS PRECEDED BY A STEP IN WHICH THE METAL SURFACE IS SUBJECTED TO AN ACTIVATION TREATMENT TO MINIMIZE PASSIVATION BY THE NITRIC ACID.
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) | 1961-11-24 | 1962-05-26 | 1962-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-11-24 | 1966-05-26 | 1966-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-11-24 | 1970-05-26 | 1970-11-25 | $7700.00 | Window Closed / Lapsed |