EP0035667A1
Expired / Lapsed
EP
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Trivalent chromium electroplating solution and bath
Assignee: International Business Machines Corp
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Filing: 1981-02-16
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Granted: —
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Expires: 2001-02-16
Abstract
Abstract A chromium electroplating solution in which the source of chromium comprises an equilibrated aqueous solution of chromium (III) - thiocyanate complexes and which has a supporting electrolyte consisting essentially of potassium sulphate or, preferably, a mixture of potassium and sodium sulphates. Such a solution is employed as the catholyte in a plating bath in which catholyte and anolyte are separated by a cation exchange membrane. This all sulphate bath permits the employment of lead anodes and has high efficiency and a good plating range.
Inventors
- 👤 Donald John Barclay
- 👤 James Michael Linford Vigar
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 08:57
CPC Classifications
C; C25; C25D; C25D3/00; C25D3/02; C25D3/04; C25D3/06
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
46 words
A chromium electroplating solution comprising an equilibrated aqueous solution of chromium (III) - thiocyanate complexes as the source of chromium and a supporting electrolyte consisting essentially of a mixture of sodium and potassium sulphates in a concentration sufficient to provide electrical conductivity for the plating process.
Claim 2
Dependent Claim
46 words
A chromium electroplating solution comprising an equilibrated aqueous solution of chromium (III) - thiocyanate complexes as the source of chromium and a supporting electrolyte consisting essentially of a mixture of sodium and potassium sulphates in a concentration sufficient to provide electrical conductivity for the plating process.
Claim 3
Dependent Claim
32 words
A solution as claimed in claim 1 wherein the potassium sulphate is present in saturation concentration and the sodium sulphate is in a concentration of less than or equal to 1 Molar.
Claim 4
Dependent Claim
14 words
A solution as claimed in claim 2 wherein the sodium concentration is 0.05 Molar.
Claim 5
Dependent Claim
32 words
A solution as claimed in any preceding claim further including aspartic acid forming one of the ligands of the complexes as an intimate buffer material and boric acid as a further buffer.
Claim 6
Dependent Claim
23 words
A solution as claimed in any preceding claim in which the source of chromium from which the complex is prepared is chromium sulphate.
Claim 7
Dependent Claim
19 words
A chromium electroplating solution substantially as hereinbefore described with reference to any one of Examples 2, 3 and 4.
Claim 8
Dependent Claim
19 words
A chromium electroplating solution substantially as hereinbefore described with reference to any one of Examples 2, 3 and 4.
Claim 9
Dependent Claim
68 words
A chromium electroplating bath comprising an anolyte and a catholyte separated by a cation exchange membrane, the catholyte being chloride free and comprising an equilibrated aqueous solution of chromium (III) - thiocyanate complexes and a supporting electrolyte comprising at least potassium sulphate in a concentration sufficient to provide electrical conductivity for the plating process, and the anolyte also being chloride free and comprising sulphate ions in aqueous solution.
Claim 10
Dependent Claim
68 words
A chromium electroplating bath comprising an anolyte and a catholyte separated by a cation exchange membrane, the catholyte being chloride free and comprising an equilibrated aqueous solution of chromium (III) - thiocyanate complexes and a supporting electrolyte comprising at least potassium sulphate in a concentration sufficient to provide electrical conductivity for the plating process, and the anolyte also being chloride free and comprising sulphate ions in aqueous solution.
Claim 11
Dependent Claim
26 words
A chromium electroplating bath as claimed in claim 7 in which the supporting electrolyte consists essentially of a mixture of sodium and potassium sulphates in solution.
Claim 12
Dependent Claim
33 words
An electroplating bath as claimed in claim 8 in which the potassium is present in saturation concentration and the sodium sulphate is in a concentration of less than or equal to 1 Molar.
Claim 13
Dependent Claim
41 words
An electroplating bath as claimed in any one of claims 7 to 9 in which the catholyte further includes aspartic acid forming one of the ligands of the complexes as an intimate buffer material and boric acid as a further buffer.
Claim 14
Dependent Claim
24 words
An electroplating bath as claimed in any one of claims 7 to 10 in which the anolyte is an aqueous solution of sulphuric acid.
Claim 15
Dependent Claim
17 words
An electroplating bath as claimed in any one of claims 7 to 11 including a lead anode.
References Cited (Backward Citations)
DE2550615A1
Cited
DE2847961A1
Cited
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