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US4331518A
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Bismuth composition, method of electroplating a tin-bismuth alloy and electroplating bath therefor
Assignee: Arkema Inc
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Filing: 1981-01-09
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Granted: 1982-05-25
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Expires: 2001-01-09
Abstract
Abstract An improved electrotinplating process and acidic electroplating bath therefor is disclosed. The acidic electroplating bath contains tin ions and a chelate salt comprising an acid bismuth sulfate gluconate. An improved electrotinplating process is therefore provided which produces an electroplated tin-bismuth alloy which is resistant to the effects of tin pest and the formation of tin whiskers.
Inventors
- 👤 Harold P. Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:16
CPC Classifications
C; C25; C25D; C25D3/00; C25D3/02; C25D3/56; C25D3/60; C07; C07F; C07F9/00; C07F9/94
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
58 words
A method of electroplating a tin and bismuth-containing alloy onto a conductive substrate comprising immersing a conductive substrate to be plated into an aqueous acidic plating bath containing tin ions, free sulfuric acid and a chelate salt comprising bismuth sulfate gluconate, and electroplating a tin and bismuth-containing alloy onto said conductive substrate as a cathode in the bath.
Claim 2
Independent Claim
58 words
A method of electroplating a tin and bismuth-containing alloy onto a conductive substrate comprising immersing a conductive substrate to be plated into an aqueous acidic plating bath containing tin ions, free sulfuric acid and a chelate salt comprising bismuth sulfate gluconate, and electroplating a tin and bismuth-containing alloy onto said conductive substrate as a cathode in the bath.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein said tin ions are provided by stannous sulfate.
Claim 4
Dependent Claim
28 words
The method of claim 1 wherein the aqueous acidic plating bath contains between about 0.06 to about 21.15 grams per liter of bismuth metal as bismuth sulfate gluconate.
Claim 5
Dependent Claim
28 words
The method of claim 1 wherein said bismuth sulfate gluconate is represented by the formula 3H 2 SO 4 .Bi 2 (SO 4 ) 3 (gluconate) 9 .
Claim 6
Dependent Claim
28 words
The method of claim 1 wherein said bismuth sulfate gluconate is represented by the formula 5H 2 SO 4 .Bi 2 (SO 4 ) 3 (gluconate) 12 .
Claim 7
Dependent Claim
49 words
The method of claim 1 wherein said conductive substrate is immersed in said bath and said tin and bismuth-containing alloy is electroplated thereon for a period of time sufficient to provide an electroplated alloy containing from about 0.15 to about 0.80 percent by weight of bismuth as bismuth metal.
Claim 8
Dependent Claim
16 words
The method of claim 1 wherein the pH of said acidic bath is less than 4.
Claim 9
Dependent Claim
13 words
The method of claim 1 wherein said acidic bath contains a brightening agent.
Claim 10
Independent Claim
101 words
A method of electroplating a tin and bismuth-containing alloy onto a conductive substrate comprising immersing a conductive substrate to be plated into an acidic aqueous plating bath containing tin ions in an amount ranging between about 10 to about 75 grams per liter, free sulfuric acid in an amount ranging between about 140 to about 215 grams per liter, and a chelate salt comprising bismuth sulfate gluconate in an amount ranging between about 0.06 to about 21.15 grams per liter expressed as bismuth metal, and electroplating a tin and bismuth-containing alloy onto said conductive substrate as a cathode in said bath.
Claim 11
Independent Claim
101 words
A method of electroplating a tin and bismuth-containing alloy onto a conductive substrate comprising immersing a conductive substrate to be plated into an acidic aqueous plating bath containing tin ions in an amount ranging between about 10 to about 75 grams per liter, free sulfuric acid in an amount ranging between about 140 to about 215 grams per liter, and a chelate salt comprising bismuth sulfate gluconate in an amount ranging between about 0.06 to about 21.15 grams per liter expressed as bismuth metal, and electroplating a tin and bismuth-containing alloy onto said conductive substrate as a cathode in said bath.
Claim 12
Dependent Claim
49 words
The method of claim 9 wherein said conductive substrate is immersed in said bath and said tin and bismuth-containing alloy is electroplated thereon for a period of time sufficient to provide an electroplated alloy containing from about 0.15 to about 0.80 percent by weight of bismuth as bismuth metal.
Claim 13
Dependent Claim
14 words
The method of claim 9 wherein said tin ions are provided by stannous sulfate.
Claim 14
Dependent Claim
31 words
An aqueous acidic solution for plating a tin and bismuth-containing alloy onto a conductive substrate which solution comprises tin ions, free sulfuric acid and an acid chelate comprising bismuth sulfate gluconate.
Claim 15
Dependent Claim
31 words
An aqueous acidic solution for plating a tin and bismuth-containing alloy onto a conductive substrate which solution comprises tin ions, free sulfuric acid and an acid chelate comprising bismuth sulfate gluconate.
Claim 16
Dependent Claim
15 words
The aqueous solution of claim 12 wherein said tin ions are provided by stannous sulfate.
Claim 17
Dependent Claim
24 words
The aqueous solution of claim 12 which comprises from about 0.06 to about 21.15 grams per liter of bismuth metal as bismuth sulfate gluconate.
Claim 18
Dependent Claim
28 words
The solution of claim 12 wherein said bismuth sulfate gluconate is represented by the formula 3H 2 SO 4 .Bi 2 (SO 4 ) 3 (gluconate) 9 .
Claim 19
Dependent Claim
28 words
The solution of claim 12 wherein said bismuth sulfate gluconate is represented by the formula 5H 2 SO 4 .Bi 2 (SO 4 ) 3 (gluconate) 12 .
Claim 20
Dependent Claim
15 words
The solution of claim 12 wherein the pH of said solution is less than 4.
Claim 21
Dependent Claim
24 words
The solution of claim 12 wherein said tin ions are present in an amount ranging from about 10 to about 75 grams per liter.
Claim 22
Dependent Claim
23 words
A composition for use in the plating of a bismuth-containing alloy comprising an aqueous solution of a chelate salt comprising bismuth sulfate gluconate.
Claim 23
Dependent Claim
23 words
A composition for use in the plating of a bismuth-containing alloy comprising an aqueous solution of a chelate salt comprising bismuth sulfate gluconate.
Claim 24
Dependent Claim
11 words
The composition of claim 19 wherein said aqueous solution is acidic.
Claim 25
Dependent Claim
13 words
The composition of claim 19 wherein said aqueous solution further comprises sulfuric acid.
Claim 26
Dependent Claim
28 words
The composition of claim 19 wherein said bismuth sulfate gluconate is represented by the formula 3H 2 SO 4 .Bi 2 (SO 4 ) 3 (gluconate) 9 .
Claim 27
Dependent Claim
28 words
The composition of claim 19 wherein said bismuth sulfate gluconate is represented by the formula 5H 2 SO 4 .Bi 2 (SO 4 ) 3 (gluconate) 12 .
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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) | 1985-05-24 | 1985-11-23 | 1986-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-05-24 | 1989-11-23 | 1990-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-05-24 | 1993-11-23 | 1994-05-25 | $7700.00 | Window Closed / Lapsed |