US3954574A
Expired / Lapsed
US
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Trivalent chromium electroplating baths and electroplating therefrom
Assignee: Solvay Solutions UK Ltd
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Filing: 1974-12-06
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Granted: 1976-05-04
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Expires: 1994-12-06
Abstract
Abstract It is known to attempt to plate chromium from a solution containing trivalent chromium salts and organic complexants. The invention provides an aqueous chromium electroplating system containing trivalent chromium, together with both a formate or acetate and a bromide. Optionally the solution also contains ammonium, borate, chloride, sulphate and alkali metal ions and a wetting agent. The invention has the advantage of providing a solution with commercially acceptable covering and throwing power whose effluent can easily be purified to acceptable standards.
Inventors
- 👤 Jeffrey Gyllenspetz
- 👤 Stanley Renton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:37
CPC Classifications
C; C25; C25D; C25D3/00; C25D3/02; C25D3/04; C25D3/06
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
58 words
An aqueous acidic chromium electroplating solution which consists essentially of (a) from 0.1 to 1.2 molar trivalent chromium, (b) carboxylate selected from formate and acetate in a proportion of from 3:1 to 0.5:1 molar based on chromium, (c) bromide in a molar ratio of bromide to chromium of from 1:1 to 1:10, and at least 0.1 molar ammonium.
Claim 2
Dependent Claim
58 words
An aqueous acidic chromium electroplating solution which consists essentially of (a) from 0.1 to 1.2 molar trivalent chromium, (b) carboxylate selected from formate and acetate in a proportion of from 3:1 to 0.5:1 molar based on chromium, (c) bromide in a molar ratio of bromide to chromium of from 1:1 to 1:10, and at least 0.1 molar ammonium.
Claim 3
Dependent Claim
13 words
The solution of claim 1 which additionally contains at least 0.1 molar borate.
Claim 4
Dependent Claim
79 words
The processes of electroplating chromium on a cathode comprising immersing an insoluble anode and a cathode in the aqueous chromium plating solution of claim 1, maintaining said solution at a pH between 1 and 4, and at a temperature between 15° and 30°C, and applying an electrical current between said anode and cathode in an amount such that the cathode current density is between about 5 and 1000 amps. per sq. foot, whereby chromium is electrodeposited on said cathode.
Claim 5
Dependent Claim
45 words
An aqueous acidic chromium plating solution consisting essentially of from 0.1 to 1.2 molar trivalent chromium; at least 0.01 molar bromide; formate in a molar ratio of formate to chromium from 3:1 to 0.5:1; at least 0.1 molar ammonium and at least 0.1 molar borate.
Claim 6
Dependent Claim
45 words
An aqueous acidic chromium plating solution consisting essentially of from 0.1 to 1.2 molar trivalent chromium; at least 0.01 molar bromide; formate in a molar ratio of formate to chromium from 3:1 to 0.5:1; at least 0.1 molar ammonium and at least 0.1 molar borate.
Claim 7
Dependent Claim
16 words
The solution of claim 4 wherein the concentration of chromium is from 0.2 to 0.6 molar.
Claim 8
Dependent Claim
15 words
The solution of claim 4 wherein the concentration of bromide is less than 1 molar.
Claim 9
Dependent Claim
16 words
The solution of claim 6 wherein the concentration of bromide is from 0.05 to 0.3 molar.
Claim 10
Dependent Claim
22 words
The solution of claim 4 wherein the concentration of formate is between 2:1 and 1:1 molar based on the concentration of chromium.
Claim 11
Dependent Claim
16 words
The solution of claim 4 wherein the concentration of ammonium is from 1 to 3 molar.
Claim 12
Dependent Claim
16 words
The solution of claim 4 wherein the concentration of borate is from 0.5 to 1 molar.
Claim 13
Dependent Claim
13 words
The solution of claim 4 containing up to 6 molar of conductivity salts.
Claim 14
Dependent Claim
12 words
The solution of claim 4 having a pH between 1 and 4.
Claim 15
Dependent Claim
12 words
The solution of claim 12 having a pH between 2 and 3.5.
Claim 16
Dependent Claim
18 words
The solution of claim 4 containing at least 0.5 molar of a halide selected from chloride and fluoride.
Claim 17
Dependent Claim
12 words
The solution of claim 14 containing from 1.5 to 5 molar chloride.
Claim 18
Dependent Claim
11 words
The solution of claim 4 containing up to 5 molar sulphate.
Claim 19
Dependent Claim
12 words
The solution of claim 16 containing from 0.5 to 4 molar sulphate.
Claim 20
Dependent Claim
79 words
The processes of electroplating chromium on a cathode comprising immersing an insoluble anode and a cathode in the aqueous chromium plating solution of claim 4, maintaining said solution at a pH between 1 and 4, and at a temperature between 15° and 30°C, and applying an electrical current between said anode and cathode in an amount such that the cathode current density is between about 5 and 1000 amps. per sq. foot, whereby chromium is electrodeposited on said cathode.
Claim 21
Dependent Claim
49 words
An aqueous acidic chromium electroplating solution consisting essentially of from 0.1 to 1.2 molar trivalent chromium; from 0.05 to 0.3 molar bromide; formate in a molar ratio of formate to chromium of from 2:1 to 1:1; from 1 to 3 molar ammonium; and from 0.5 to 1 molar borate.
Claim 22
Dependent Claim
49 words
An aqueous acidic chromium electroplating solution consisting essentially of from 0.1 to 1.2 molar trivalent chromium; from 0.05 to 0.3 molar bromide; formate in a molar ratio of formate to chromium of from 2:1 to 1:1; from 1 to 3 molar ammonium; and from 0.5 to 1 molar borate.
Claim 23
Dependent Claim
38 words
The solution of claim 19 having a pH of from 1 to 4 and containing from 1.5 to 5 molar chloride and at least 0.5 molar sulphate the proportion of sulphate being smaller than the proportion of chloride.
Claim 24
Dependent Claim
38 words
The solution of claim 19 having a pH of from 1 to 4 and containing from 0.5 to 4 molar sulphate and at least 0.5 molar chloride the proportion of chloride being less than the proportion of sulphate.
Claim 25
Dependent Claim
28 words
The solution of claim 19 having a pH of from 1 to 4 and containing from 2.5 to 3.5 molar total of anion selected from chloride and sulphate.
Claim 26
Dependent Claim
79 words
The processes of electroplating chromium on a cathode comprising immersing an insoluble anode and a cathode in the aqueous chromium plating solution of claim 11, maintaining said solution at a pH between 1 and 4, and at a temperature between 15° and 30°C, and applying an electrical current between said anode and cathode in an amount such that the cathode current density is between about 5 and 1000 amps. per sq. foot, whereby chromium is electrodeposited on said cathode.
Claim 27
Dependent Claim
68 words
An aqueous chromium plating solution consisting essentially of water, from 0.2 to 0.6 molar trivalent chromium, from 0.05 to 0.3 molar bromide, formate in a molar ratio of formate to chromium of from 2:1 to 1:1, from 1 to 3 molar ammonium, from 0.5 to 1 molar borate, from 2.5 to 3.5 molar of anion selected from chloride and sulphate amd having a pH between 1 and 4.
Claim 28
Dependent Claim
68 words
An aqueous chromium plating solution consisting essentially of water, from 0.2 to 0.6 molar trivalent chromium, from 0.05 to 0.3 molar bromide, formate in a molar ratio of formate to chromium of from 2:1 to 1:1, from 1 to 3 molar ammonium, from 0.5 to 1 molar borate, from 2.5 to 3.5 molar of anion selected from chloride and sulphate amd having a pH between 1 and 4.
Claim 29
Dependent Claim
13 words
Solution of claim 24 containing from 0 to 6 molar alkali metal cation.
Claim 30
Dependent Claim
16 words
The solution of claim 25 containing an effective and compatible amount of a non-brominatable wetting agent.
Claim 31
Dependent Claim
22 words
The solution of claim 26 containing up to saturation of a co-depositable metal cation selected from iron, cobalt, nickel, manganese and tungsten.
Claim 32
Dependent Claim
79 words
The processes of electroplating chromium on a cathode comprising immersing an insoluble anode and a cathode in the aqueous chromium plating solution of claim 22, maintaining said solution at a pH between 1 and 4, and at a temperature between 15° and 30°C, and applying an electrical current between said anode and cathode in an amount such that the cathode current density is between about 5 and 1000 amps. per sq. foot, whereby chromium is electrodeposited on said cathode.
Claim 33
Dependent Claim
23 words
The process of claim 28 wherein said pH is between about 2 and 3.5; and said temperature is between about 20° and 25°C.
Claim 34
Dependent Claim
16 words
The process of claim 29 wherein said current density is about 100 amps. per sq. foot.
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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) | 1979-05-04 | 1979-11-03 | 1980-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-04 | 1983-11-03 | 1984-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-04 | 1987-11-03 | 1988-05-04 | $7700.00 | Window Closed / Lapsed |