US4316752A
Expired / Lapsed
US
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Oxalic acid treatment of carbon steel, galvanized steel and aluminum surfaces
Assignee: International Lead Zinc Research Organization Inc
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Filing: 1980-10-16
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Granted: 1982-02-23
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Expires: 2000-10-16
Abstract
Abstract The surface of a metal, namely, carbon steel (automotive steel), galvanized steel and/or aluminum, can be modified by treating the metal surface with a dilute aqueous oxalic acid solution. The resultant oxalic acid treated metal surface can be further treated with a phosphatizing bath. Such dual treatment improves the corrosion resistance of the metal surface and is particularly useful in the treatment of lighter weight automobile bodies having joints of carbon steel, galvanized steel and/or aluminum.
Inventors
- 👤 Max Kronstein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:47
CPC Classifications
B; B24; B24B; B24B31/00; B24B31/12; B24B31/14; C; C23; C23C; C23C22/00; C23C22/05; C23C22/06; C23C22/46; C23C22/73
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
83 words
A process for modifying the surface of a metal, characterized by treating the metal surface for from about 0.5 minute to about 10 minutes with a dilute aqueous oxalic acid solution having a temperature in the range of from about 65° C. to about 90° C. and consisting essentially of from about 2% to about 5% by weight oxalic acid and the balance water, the metal being at least one metal selected from the group consisting of carbon steel, galvanized steel and aluminum.
Claim 2
Dependent Claim
83 words
A process for modifying the surface of a metal, characterized by treating the metal surface for from about 0.5 minute to about 10 minutes with a dilute aqueous oxalic acid solution having a temperature in the range of from about 65° C. to about 90° C. and consisting essentially of from about 2% to about 5% by weight oxalic acid and the balance water, the metal being at least one metal selected from the group consisting of carbon steel, galvanized steel and aluminum.
Claim 3
Dependent Claim
21 words
The process according to claim 1, characterized by the aqueous oxalic acid solution has a concentration of about 3% by weight.
Claim 4
Dependent Claim
20 words
The process according to claim 1, characterized by further treating the resultant oxalic acid-treated metal surface with a phosphatizing bath.
Claim 5
Dependent Claim
32 words
The process according to claim 3, characterized by treating the metal surface with a phosphoric acid pickling solution prior to treatment of the metal surface with the dilute aqueous oxalic acid solution.
Claim 6
Dependent Claim
35 words
The process according to claim 3, characterized by treating the metal surface with a stripping solution comprising hydrochloric acid and formaldehyde prior to treatment of the metal surface with the dilute aqueous oxalic acid solution.
Claim 7
Dependent Claim
29 words
The process according to claim 3, characterized by treating the metal surface successively with the dilute aqueous oxalic acid solution, a phosphoric acid pickling solution, and the phosphatizing bath.
Claim 8
Dependent Claim
35 words
The process according to claim 3, characterized by treating the metal surface successively with the dilute aqueous oxalic acid solution, a phosphoric acid pickling solution, the dilute aqueous oxalic acid solution and the phosphatizing bath.
Claim 9
Dependent Claim
23 words
The process according to claims 3, 4, 5, 6 or 7, characterized by treating the phosphatized metal surface with a chromic acid sealer.
Claim 10
Dependent Claim
23 words
The process according to claims 3, 4, 5, 6, or 7, characterized by rinsing the metal surface with water between each treatment step.
Claim 11
Dependent Claim
31 words
The process according to claim 1, characterized by the dilute aqueous oxalic acid solution also contains a ligand-forming organic polymer selected from the group consisting of polyvinyl alcohol and methyl cellulose.
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) | 1985-02-22 | 1985-08-24 | 1986-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-02-22 | 1989-08-24 | 1990-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-02-22 | 1993-08-24 | 1994-02-23 | $7700.00 | Window Closed / Lapsed |