US4054494A
Expired / Lapsed
US
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Compositions for use in chromium plating
Assignee: Solvay Solutions UK Ltd
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Filing: 1975-12-02
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Granted: 1977-10-18
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Expires: 1995-12-02
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
2026-10-24 05:14
CPC Classifications
C; C25; C25D; C25D3/00; C25D3/02; C25D3/04; C25D3/06
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
46 words
An aqueous chromium electroplating solution consisting essentially of from 0.1 to 1.2 molar trivalent chromium; at least 0.1 molar bromide; formate in a proportion of from 3 to 0.5 moles per mole of the chromium; at least 0.1 molar ammonium and at least 0.1 molar borate.
Claim 2
Dependent Claim
46 words
An aqueous chromium electroplating solution consisting essentially of from 0.1 to 1.2 molar trivalent chromium; at least 0.1 molar bromide; formate in a proportion of from 3 to 0.5 moles per mole of the chromium; at least 0.1 molar ammonium and at least 0.1 molar borate.
Claim 3
Dependent Claim
16 words
The solution of claim 1 wherein the concentration of chromium is from 0.2 to 0.6 molar.
Claim 4
Dependent Claim
15 words
The solution of claim 1 wherein the concentration of bromide is less than 1 molar.
Claim 5
Dependent Claim
16 words
The solution of claim 3 wherein the concentration of bromide is from 0.1 to 0.3 molar.
Claim 6
Dependent Claim
20 words
The solution of claim 1 wherein the proportion of formate is between 2 and 1 moles per mole of chromium.
Claim 7
Dependent Claim
16 words
The solution of claim 1 wherein the concentration of ammonium is from 1 to 3 molar.
Claim 8
Dependent Claim
16 words
The solution of claim 1 wherein the concentration of borate is from 0.5 to 1 molar.
Claim 9
Dependent Claim
13 words
The solution of claim 1 containing up to 6 molar of conductivity salts.
Claim 10
Dependent Claim
25 words
The solution of claim 1 containing from 1 to 5 moles of alkali metal ions selected from the group consisting of sodium and potassium ions.
Claim 11
Dependent Claim
12 words
The solution of claim 1 having a pH between 1 and 4.
Claim 12
Dependent Claim
17 words
The solution of claim 1 containing at least 0.5 molar of halide selected from chloride and fluoride.
Claim 13
Dependent Claim
12 words
The solution of claim 11 containing from 1.5 to 5 molar chloride.
Claim 14
Dependent Claim
11 words
The solution of claim 1 containing up to 3 molar sulphate.
Claim 15
Dependent Claim
12 words
The solution of claim 1 containing from 0.5 to 4 molar sulphate.
Claim 16
Dependent Claim
37 words
The solution of claim 1 having a pH 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 17
Dependent Claim
60 words
An aqueous chromium electroplating solution consisting essentially of from 0.1 to 1.2 molar trivalent chromium; from 0.05 to 0.3 molar bromide; from 2 to 1 moles formate per mole of chromium; from 1 to 3 molar ammonium; from 0.5 to 1 molar borate; and from 1 to 5 moles per liter of alkali metal ions selected from sodium and potassium.
Claim 18
Dependent Claim
60 words
An aqueous chromium electroplating solution consisting essentially of from 0.1 to 1.2 molar trivalent chromium; from 0.05 to 0.3 molar bromide; from 2 to 1 moles formate per mole of chromium; from 1 to 3 molar ammonium; from 0.5 to 1 molar borate; and from 1 to 5 moles per liter of alkali metal ions selected from sodium and potassium.
Claim 19
Dependent Claim
18 words
The solution of claim 16 containing from 2 to 4 moles per liter of said alkali metal ions.
Claim 20
Dependent Claim
12 words
The solution of claim 16 having a pH between 1 and 4.
Claim 21
Dependent Claim
12 words
The solution of claim 16 having a pH between 2 and 3.5.
Claim 22
Dependent Claim
38 words
The solution of claim 16 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 23
Dependent Claim
28 words
The solution of claim 16 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 24
Dependent Claim
97 words
An aqueous chromium electroplating bath consisting essentially of water, from 0.2 to 0.6 molar trivalent chromium, from 0.05 to 0.3 molar bromide, from 2 to 1 moles formate per mole of trivalent chromium, from 0.2 to 3 molar ammonium, from 0.5 to 1 molar borate, from 2 to 4 molar total of anions selected from chloride and sulphate including at least 0.5 molar chloride and at least 0.5 molar sulphate and from 2 molar to saturation of alkali metal cations selected from the group consisting of sodium and potassium, and having a pH between 1 and 4.
Claim 25
Dependent Claim
97 words
An aqueous chromium electroplating bath consisting essentially of water, from 0.2 to 0.6 molar trivalent chromium, from 0.05 to 0.3 molar bromide, from 2 to 1 moles formate per mole of trivalent chromium, from 0.2 to 3 molar ammonium, from 0.5 to 1 molar borate, from 2 to 4 molar total of anions selected from chloride and sulphate including at least 0.5 molar chloride and at least 0.5 molar sulphate and from 2 molar to saturation of alkali metal cations selected from the group consisting of sodium and potassium, and having a pH between 1 and 4.
Claim 26
Dependent Claim
18 words
The solution of claim 22 containing from 1 to 3 molar ammonium and at least 2 molar chloride.
Claim 27
Dependent Claim
16 words
The solution of claim 22 containing an effective and compatible amount of a cationic wetting agent.
Claim 28
Dependent Claim
16 words
The solution of claim 22 containing an effective and compatible amount of an anionic wetting agent.
Claim 29
Independent Claim
258 words
A method for the preparation of trivalent chromium electroplating baths comprising dissolving in water: a. a composition consisting essentially of i. borate ions present as a borate compound selected from boric acid and alkali metal and ammonium borate; ii. at least one alkali metal salt selected from sodium chloride, potassium chloride, sodium fluoride, potassium fluoride, sodium sulphate and potassium sulphate; iii. bromide present as a salt selected from sodium, potassium and ammonium bromide; and iv. an ammonium salt selected from ammonium chloride, ammonium fluoride, ammonium sulphate and said ammonium borate, said borate ions being present in a proportion of at least 1% of the total weight of the components a, b, c and d, said bromide being present in a proportion of at least 0.5%, measured as HBr of the total weight of the components a, b, c and d, said alkali metal salt being present in a proportion of at least 2% by weight of the dry weight of the composition, said ammonium salt being present in a proportion of from 5 to 80% by weight of the total weight of the components a, b, c and d in a proportion sufficient to provide at least 0.01 molar bromide and up to saturation; b. sufficient of a trivalent chromium salt to provide of from 0.1 to 1.2 molar trivalent chromium; c. sufficient of a water soluble formate to provide of from 2 to 1 moles of formate per mole of trivalent chromium; and adjusting the pH of the bath of a value of between 1 and 4.
Claim 30
Independent Claim
258 words
A method for the preparation of trivalent chromium electroplating baths comprising dissolving in water: a. a composition consisting essentially of i. borate ions present as a borate compound selected from boric acid and alkali metal and ammonium borate; ii. at least one alkali metal salt selected from sodium chloride, potassium chloride, sodium fluoride, potassium fluoride, sodium sulphate and potassium sulphate; iii. bromide present as a salt selected from sodium, potassium and ammonium bromide; and iv. an ammonium salt selected from ammonium chloride, ammonium fluoride, ammonium sulphate and said ammonium borate, said borate ions being present in a proportion of at least 1% of the total weight of the components a, b, c and d, said bromide being present in a proportion of at least 0.5%, measured as HBr of the total weight of the components a, b, c and d, said alkali metal salt being present in a proportion of at least 2% by weight of the dry weight of the composition, said ammonium salt being present in a proportion of from 5 to 80% by weight of the total weight of the components a, b, c and d in a proportion sufficient to provide at least 0.01 molar bromide and up to saturation; b. sufficient of a trivalent chromium salt to provide of from 0.1 to 1.2 molar trivalent chromium; c. sufficient of a water soluble formate to provide of from 2 to 1 moles of formate per mole of trivalent chromium; and adjusting the pH of the bath of a value of between 1 and 4.
Claim 31
Dependent Claim
12 words
A method according to claim 26 wherein the formate is ammonium formate.
Claim 32
Dependent Claim
17 words
A method according to claim 26 wherein the trivalent chromium salt is a basic trivalent chromium sulphate.
Claim 33
Dependent Claim
32 words
A method according to claim 26 wherein the bath is plated out for a total of 0.5 ampere hours per liter commencing not less than 12 hours after preparation of the solution.
Claim 34
Dependent Claim
32 words
A method according to claim 29 wherein the bath is plated out for at least 20 ampere hours per liter commencing not less than 12 hours after the preparation of the solution.
Claim 35
Independent Claim
216 words
A method for the maintenance of a trivalent chromium electroplating bath which comprises adding thereto at separate intervals each of less than three days: a. a composition consisting essentially of i. borate ions present as a borate compound selected from boric acid and alkali metal and ammonium borate; ii. at least one alkali metal salt selected from sodium chloride, potassium chloride, sodium fluoride, potassium fluoride, sodium sulphate and potassium sulphate; iii. bromide present as a salt selected from sodium, potassium and ammonium bromide; and iv. an ammonium salt selected from ammonium chloride, ammonium fluoride, ammonium sulphate and said ammonium borate, said borate ions being present in a proportion of at least 1% of the total weight of the components a, b, c and d, said bromide being present in a proportion of at least 0.5%, measured as HBr of the total weight of the components a, b, c and d, said alkali metal salt being present in a proportion of at least 2% by weight of the dry weight of the composition, said ammonium salt being present in a proportion of from 5 to 80% by weight of the total weight of the components a, b, c and d in an amount sufficient to maintain the concentration of bromide in the bath at least 0.1 molar.
Claim 36
Independent Claim
216 words
A method for the maintenance of a trivalent chromium electroplating bath which comprises adding thereto at separate intervals each of less than three days: a. a composition consisting essentially of i. borate ions present as a borate compound selected from boric acid and alkali metal and ammonium borate; ii. at least one alkali metal salt selected from sodium chloride, potassium chloride, sodium fluoride, potassium fluoride, sodium sulphate and potassium sulphate; iii. bromide present as a salt selected from sodium, potassium and ammonium bromide; and iv. an ammonium salt selected from ammonium chloride, ammonium fluoride, ammonium sulphate and said ammonium borate, said borate ions being present in a proportion of at least 1% of the total weight of the components a, b, c and d, said bromide being present in a proportion of at least 0.5%, measured as HBr of the total weight of the components a, b, c and d, said alkali metal salt being present in a proportion of at least 2% by weight of the dry weight of the composition, said ammonium salt being present in a proportion of from 5 to 80% by weight of the total weight of the components a, b, c and d in an amount sufficient to maintain the concentration of bromide in the bath at least 0.1 molar.
Claim 37
Dependent Claim
23 words
b. a trivalent chromium salt in an amount sufficient to maintain the concentration of chromium in the bath between 0.1 and 1.2 molar.
Claim 38
Dependent Claim
23 words
b. a trivalent chromium salt in an amount sufficient to maintain the concentration of chromium in the bath between 0.1 and 1.2 molar.
Claim 39
Dependent Claim
26 words
c. a formate in an amount sufficient to maintain a concentration of formate in the bath from 1 to 2 moles per mole of trivalent chromium.
Claim 40
Dependent Claim
26 words
c. a formate in an amount sufficient to maintain a concentration of formate in the bath from 1 to 2 moles per mole of trivalent chromium.
Claim 41
Dependent Claim
17 words
d. sufficient of an aqueous alkali to maintain the pH of the bath between 1 and 4.
Claim 42
Dependent Claim
17 words
d. sufficient of an aqueous alkali to maintain the pH of the bath between 1 and 4.
Claim 43
Dependent Claim
116 words
An aqueous electroplating bath for electrodepositing chromium-iron alloys consisting essentially of water, from 0.2 to 0.6 molar trivalent chromium and iron cation in an amount up to saturation for the electrodeposition of chromium-iron alloys, from 0.05 to 0.3 molar bromide, from 2 to 1 moles formate per mole of trivalent chromium, from 0.2 to 3 molar ammonium, from 0.5 to 1 molar borate, from 2 to 4 molar total of anions selected from chloride and sulphate including at least 0.5 molar chloride and at least 0.5 molar sulphate and from 2 molar to saturation of alkali metal cations selected from the group consisting of sodium and potassium and having a pH of between 1 and 4.
Claim 44
Dependent Claim
116 words
An aqueous electroplating bath for electrodepositing chromium-iron alloys consisting essentially of water, from 0.2 to 0.6 molar trivalent chromium and iron cation in an amount up to saturation for the electrodeposition of chromium-iron alloys, from 0.05 to 0.3 molar bromide, from 2 to 1 moles formate per mole of trivalent chromium, from 0.2 to 3 molar ammonium, from 0.5 to 1 molar borate, from 2 to 4 molar total of anions selected from chloride and sulphate including at least 0.5 molar chloride and at least 0.5 molar sulphate and from 2 molar to saturation of alkali metal cations selected from the group consisting of sodium and potassium and having a pH of between 1 and 4.
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) | 1980-10-17 | 1981-04-18 | 1981-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-17 | 1985-04-18 | 1985-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-17 | 1989-04-18 | 1989-10-18 | $7700.00 | Window Closed / Lapsed |