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US4486513A
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Process for producing rhodium-plated article with black color and wear resistance
Assignee: Nippon Metal Plating Co Ltd
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Filing: 1982-03-24
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Granted: 1984-12-04
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Expires: 2002-03-24
Abstract
Abstract A process for improving the wear resistance and enhancing the black color of a black rhodium plated article which comprises subjecting the article to anodic electrolysis.
Inventors
- 👤 Masayoshi Mashiko
- 👤 Keijiro Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:29
CPC Classifications
C; C25; C25D; C25D11/00; C25D11/02; C25D11/34; C25D3/00; C25D3/02; C25D3/50; C25D3/52; C25D5/00; C25D5/48; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12771; Y10T428/12861; Y10T428/12875
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
138 words
A process for improving the wear resistance and enhancing the black color of a black rhodium-plated article which comprises subjecting a black rhodium-plated article to anodic electrolysis wherein the anodic electrolysis is carried out in a bath comprising one or more ingredients selected from the group consisting of: organic acids selected from the group consisting of citric acid, glutamic acid, tartaric acid, acetic acid, stearic acid, lactic acid, succinic acid, sulfamic acid and salts thereof; inorganic acids selected from the group consisting of pyrophosphoric acid, phosphoric acid, carbonic acid, cyanic acid, boric acid, silicic acid and salts thereof, methyl alcohol, ethyl alcohol, ethylene glycol, benzylamine, cyclohexane, EDTA, sodium saccharinate, polyacrylamide, polyethylene imine, triethanolamine and ammonia water; with a direct current of a current density of 0.004-20 A/dm 2 and a bath temperature for 20°-60° C. for 3-60 minutes.
Claim 2
Dependent Claim
138 words
A process for improving the wear resistance and enhancing the black color of a black rhodium-plated article which comprises subjecting a black rhodium-plated article to anodic electrolysis wherein the anodic electrolysis is carried out in a bath comprising one or more ingredients selected from the group consisting of: organic acids selected from the group consisting of citric acid, glutamic acid, tartaric acid, acetic acid, stearic acid, lactic acid, succinic acid, sulfamic acid and salts thereof; inorganic acids selected from the group consisting of pyrophosphoric acid, phosphoric acid, carbonic acid, cyanic acid, boric acid, silicic acid and salts thereof, methyl alcohol, ethyl alcohol, ethylene glycol, benzylamine, cyclohexane, EDTA, sodium saccharinate, polyacrylamide, polyethylene imine, triethanolamine and ammonia water; with a direct current of a current density of 0.004-20 A/dm 2 and a bath temperature for 20°-60° C. for 3-60 minutes.
Claim 3
Dependent Claim
21 words
The process as defined in claim 1, wherein the anodic electrolysis is carried out under a bath potential of 1-10 volts.
Claim 4
Dependent Claim
16 words
The process as defined in claim 1, wherein the current density is 0.004-0.5 A/dm 2 .
Claim 5
Dependent Claim
16 words
The process is defined in claim 1, wherein the current density is 0.1-20 A/dm 2 .
Claim 6
Dependent Claim
13 words
The process as defined in claim 1, wherein the temperature is 20° C.
Claim 7
Dependent Claim
13 words
The process as defined in claim 1, wherein the temperature is 30°-60° C.
Claim 8
Dependent Claim
108 words
The process as defined in claim 1, wherein the starting black rhodium-plated article is produced by a process for electroplating rhodium on an article which comprises: preparing a rhodium-plating bath comprising 0.1 to 20 g/l of a rhodium salt, a free acid which is selected from the group consisting of sulfuric acid, phosphoric acid, sulfamic acid and a combination thereof, and an additive consisting of at least one selected from the group consisting of an organocarboxylic acid, an aromatic sulfonic acid or salts of these, amine, gelatine, butynediol and hypophosphite, and electroplating an article in said rhodium-plating bath under such conditions that the rhodium-plating film develops black color.
Claim 9
Dependent Claim
14 words
A product obtained through the process as defined in claim 1 or claim 7.
References Cited (Backward Citations)
GB446393A
Cited
US2738897A
Cited
US3290233A
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US4052271A
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US3763002A
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JPS5224131A
Cited
JPS531648A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-12-04 | 1988-06-04 | 1988-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-04 | 1992-06-04 | 1992-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-04 | 1996-06-04 | 1996-12-04 | $7700.00 | Window Closed / Lapsed |