Patent US3337431A successfully refreshed from Google Patents.
US3337431A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrochemical treatment of metal surfaces
Assignee: Toyo Kohan Co Ltd
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Filing: 1963-10-30
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Granted: 1967-08-22
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Expires: 1983-10-30
Abstract
No abstract record available.
Inventors
- 👤 Kitamura Yoichi
- 👤 Inui Tsuneo
- 👤 Shuto Etsuro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:24
CPC Classifications
C; C25; C25D; C25D11/00; C25D11/38
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
120 words
A METHOD OF FORMING A PROTECTIVE COATING OF HYDRATED CHROMIUM OXIDE ON A METAL SURFACE, WHICH COMPRISES PREPARING AN ELECTROLYTIC BATH BY ADDING TO AN AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF 10-100 GRAMS PER LITER OF CHROMIC ACID, A WATER SOLUBLE ORGANIC HYDROXYL COMPOUND IN SUCH A STOICHIOMETRICAL AMOUNT THAT NOT MORE THAN 2.5 GRAMS PER LITER OF TRIVALENT CHROMIUM ION AND 20-150 PARTS BY WEIGHT OF HEXAVALENT CHROMIUM ION PER PART OF TRIVALENT CHROMIUM ION ARE FORMED, 0.1-0.5 GRAM PER LITER OF SULFURIC ACID AND AN INORGANIC FLUORINE COMPOUND PRESENT IN AN AMOUNT UP TO 1.0 GRAM PER LITER, AND EFFECTING ELECTROLYSIS IN SAID ELECTROLYTIC BATH USING AS CATHODE THE METAL TO BE COATED AN AN ANODE OF LEADBASE METAL.
Claim 2
Independent Claim
120 words
A METHOD OF FORMING A PROTECTIVE COATING OF HYDRATED CHROMIUM OXIDE ON A METAL SURFACE, WHICH COMPRISES PREPARING AN ELECTROLYTIC BATH BY ADDING TO AN AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF 10-100 GRAMS PER LITER OF CHROMIC ACID, A WATER SOLUBLE ORGANIC HYDROXYL COMPOUND IN SUCH A STOICHIOMETRICAL AMOUNT THAT NOT MORE THAN 2.5 GRAMS PER LITER OF TRIVALENT CHROMIUM ION AND 20-150 PARTS BY WEIGHT OF HEXAVALENT CHROMIUM ION PER PART OF TRIVALENT CHROMIUM ION ARE FORMED, 0.1-0.5 GRAM PER LITER OF SULFURIC ACID AND AN INORGANIC FLUORINE COMPOUND PRESENT IN AN AMOUNT UP TO 1.0 GRAM PER LITER, AND EFFECTING ELECTROLYSIS IN SAID ELECTROLYTIC BATH USING AS CATHODE THE METAL TO BE COATED AN AN ANODE OF LEADBASE METAL.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1970-08-21 | 1971-02-20 | 1971-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-08-21 | 1975-02-20 | 1975-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-08-21 | 1979-02-20 | 1979-08-22 | $7700.00 | Window Closed / Lapsed |