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US4664759A
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Method for forming adherent, bright, smooth and hard chromium electrodeposits on stainless steel substrates from high energy efficient chromium baths
Assignee: M&T HARSHAW
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Filing: 1985-10-15
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Granted: 1987-05-12
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Expires: 2005-10-15
Abstract
Abstract An activation solution is provided for forming adherent chromium electrodeposits on stainless steel substrates from high energy efficient chromium baths. The activation solution suitably is a mixture of chromium acid, and chloride ion, or a mixture of chloride and bromide ions. A preferred solution contains 0.15M chromic acid and 0.14M chloride ion, or with 0.025M bromide ion, and the stainless steel is anodically etched in the activation solution at about 55° C.
Inventors
- 👤 Hyman Chessin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 21:05
CPC Classifications
C; C25; C25D; C25D5/00; C25D5/34; C25D5/36
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
57 words
A method of forming an adherent, bright, smooth and hard chromium deposit on a stainless steel substrate comprising the steps of: (a) activating said substrate by electrolytic etching in an activation solution consisting essentially of chromic acid and chloride ion, or a mixture of chloride ion and bromide ion, and (b) electrodepositing chromium on said thus-treated substrate.
Claim 2
Independent Claim
57 words
A method of forming an adherent, bright, smooth and hard chromium deposit on a stainless steel substrate comprising the steps of: (a) activating said substrate by electrolytic etching in an activation solution consisting essentially of chromic acid and chloride ion, or a mixture of chloride ion and bromide ion, and (b) electrodepositing chromium on said thus-treated substrate.
Claim 3
Dependent Claim
19 words
The method according to claim 1, further including the step of rinsing the activated substrate before electrodepositing chromium thereon.
Claim 4
Dependent Claim
21 words
A method according to claim 1 in which activation is carried out at a temperature of at least about 40° C.
Claim 5
Dependent Claim
21 words
A method according to claim 1 in which said chloride ion is present in a concentration of less than 0.30 M.
Claim 6
Dependent Claim
20 words
A method according to claim 1 in which chloride ion is present in a concentration of at least 0.10 M.
Claim 7
Dependent Claim
19 words
A method according to claim 1 in which said activation solution consists essentially of chromic acid and chloride ion.
Claim 8
Dependent Claim
18 words
A method according to claim 1 in which chromium is deposited from a high energy efficient chromium bath.
Claim 9
Dependent Claim
21 words
A method according to claim 1 in which said activation solution consists essentially of chromic acid, chloride ion and bromide ion.
Claim 10
Dependent Claim
17 words
A method according to claim 1 in which said electrolytic etching is carried out by anodic etching.
Claim 11
Dependent Claim
42 words
A method according to claim 1 in which the activation step is carried out for about 10 seconds to 10 minutes at a current density of about 2.5 asi for 1-3 minutes at a temperature between about 55° C. to 60° C.
Claim 12
Dependent Claim
21 words
A method according to claim 1 in which said electrolytic etching is carried out by anodic etching followed by cathodic etching.
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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) | 1990-05-11 | 1990-11-10 | 1991-05-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-11 | 1994-11-10 | 1995-05-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-11 | 1998-11-10 | 1999-05-12 | $7700.00 | Window Closed / Lapsed |