US3629078A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for surface treatment of zinc-plated sheet steel
Assignee: Nippon Steel Corp
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Filing: 1969-06-27
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Granted: 1971-12-21
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Expires: 1989-06-27
Abstract
Abstract Method of the surface treatment of zinc-plated sheet steel, wherein cathodic electrolysis of the surface of zinc-plated sheet steel is provided as a pretreatment of the surface treatment with chromic acid of said zinc-plated sheet steel, for the prevention of white rust.
Inventors
- 👤 Hideya Okada
- 👤 Shozo Matsuda
- 👤 Misao Ohbu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 04:36
CPC Classifications
C; C23; C23C; C23C22/00; C23C22/78; C25; C25D; C25D11/00; C25D11/38
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
37 words
The method according to claim 1 wherein said cathodic electrolysis is carried out in a diluted aqueous solution of at least one stable neutral salt selected from the group consisting of KCl, NaCl (NH4)2CO3, (NH4)2CrO4 and (NH4)2Cr2O7.
Claim 2
Dependent Claim
25 words
The method according to claim 1 wherein said cathodic electrolysis is carried out in an electrolyte of the pH value ranging from 6 to 10.
Claim 3
Dependent Claim
43 words
The method according to claim 1 wherein said cathodic electrolysis is carried out in the electrolyte of the pH value ranging from 6 to 10 and at a current density of 5 to 20 A./dm.2 for a period of 1 to 2 seconds.
Claim 4
Dependent Claim
32 words
The method according to claim 1 wherein the surface treatment with chromic acid is carried out in a aqueous solution either of chromic acid alone or containing it as the main ingredient.
Claim 5
Dependent Claim
18 words
The method according to claim 1 wherein the surface treatment with chromic acid is carried out by immersion.
Claim 6
Dependent Claim
18 words
The method according to claim 1 wherein the surface treatment with chromic acid is carried out by electrolysis.
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) | 1974-12-20 | 1975-06-21 | 1975-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-20 | 1979-06-21 | 1979-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-20 | 1983-06-21 | 1983-12-21 | $7700.00 | Window Closed / Lapsed |