US3413160A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Passivation of ferrous metal surface
Assignee: Dow Chemical Co
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Filing: 1965-10-24
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Granted: 1968-11-26
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Expires: 1985-10-24
Abstract
No abstract record available.
Inventors
- 👤 Fred N Teumac
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 06:20
CPC Classifications
C; C23; C23C; C23C22/00; C23C22/05; C23C22/60; C23C22/62; C23C22/73; C23C22/77; F; F28; F28F; F28F19/00
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
100 words
IN THE METHOD OF PASSIVATING A FERROUS METAL SURFACE IN CONTACT WITH AN AQUEOUS SOLUTION EXHIBITING AN ALKALINE PH AND CONTAINING BOTH FERRIC AND FERROUS ION SPECIES IN WHICH ADDITIONS OF OXIDIZING AGENT ARE MADE TO THE SAID AQUEOUS SOLUTION, THE IMPROVEMENT WHICH COMPRISES: MONITORING THE STATE OF OXIDATION EXHIBITED BY THE FERRIC IRON CONCENTRATION-FERROUS IRON CONCENTRATION RATIO DURING THE ADDITION OF OXIDIZING AGENT AND STOPPING SUCH ADDITION WHEN THE OXIDATION POTENTIAL OF THE SAID AQUEOUS SOLUTION IS IN THE RANGE OF 250 TO 175 MILLIVOLTS AS MEASURED WITH A FERROUS METAL ELECTRODE WITH REFERENCE TO A SATURATED CALOMEL ELECTRODE.
Claim 2
Dependent Claim
100 words
IN THE METHOD OF PASSIVATING A FERROUS METAL SURFACE IN CONTACT WITH AN AQUEOUS SOLUTION EXHIBITING AN ALKALINE PH AND CONTAINING BOTH FERRIC AND FERROUS ION SPECIES IN WHICH ADDITIONS OF OXIDIZING AGENT ARE MADE TO THE SAID AQUEOUS SOLUTION, THE IMPROVEMENT WHICH COMPRISES: MONITORING THE STATE OF OXIDATION EXHIBITED BY THE FERRIC IRON CONCENTRATION-FERROUS IRON CONCENTRATION RATIO DURING THE ADDITION OF OXIDIZING AGENT AND STOPPING SUCH ADDITION WHEN THE OXIDATION POTENTIAL OF THE SAID AQUEOUS SOLUTION IS IN THE RANGE OF 250 TO 175 MILLIVOLTS AS MEASURED WITH A FERROUS METAL ELECTRODE WITH REFERENCE TO A SATURATED CALOMEL ELECTRODE.
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) | 1971-11-26 | 1972-05-27 | 1972-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-11-26 | 1976-05-27 | 1976-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-11-26 | 1980-05-27 | 1980-11-26 | $7700.00 | Window Closed / Lapsed |