US4162205A
Expired / Lapsed
US
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Method of electroplating tin and alkaline electroplating bath therefor
Assignee: M&T HARSHAW
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Filing: 1978-10-19
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Granted: 1979-07-24
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Expires: 1998-10-19
Abstract
Abstract An improved electrotinplating process and electroplating bath therefor is disclosed. The electroplating bath contains tin ions, an alkali metal hydroxide, and a bismuth compound selected from the group consisting of at least one alkali metal bismuth salt of a linear polyhydroxymonocarboxylic acid having at least six carbon atoms, at least one alkali metal bismuthyl compound of glucono-delta-lactone, and mixtures thereof. The alkali metal bismuth compounds of this invention exhibit increased solubility and long-term stability in hot alkaline alkali metal stannate electroplating baths when compared to conventional alkali metal bismuthates. A preferred alkali metal bismuth compound is an alkali metal bismuthyl gluconate. An improved electrotinplating process is therefore provided which produces a plated tin-bismuth alloy which is resistant to the effects of tin pest.
Inventors
- 👤 Harold P. Wilson
- 👤 Walter C. Bradbury
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 02:16
CPC Classifications
C; C25; C25D; C25D3/00; C25D3/02; C25D3/56; C25D3/60
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
96 words
In a method for electroplating a tin-containing alloy onto a conductive substrate comprising immersing a conductive substrate to be plated into an aqueous alkaline plating bath containing tin ions, alkali metal hydroxide, and a bismuth compound, and electroplating a tin-containing alloy onto the substrate as a cathode in the bath, the improvement comprising using as the bismuth compound a compound selected from the group consisting of at least one alkali metal bismuth salt of a linear polyhydroxymonocarboxylic acid having at least six carbon atoms, at least one alkali metal bismuthyl compound of glucono-delta-lactone, and mixtures thereof.
Claim 2
Dependent Claim
96 words
In a method for electroplating a tin-containing alloy onto a conductive substrate comprising immersing a conductive substrate to be plated into an aqueous alkaline plating bath containing tin ions, alkali metal hydroxide, and a bismuth compound, and electroplating a tin-containing alloy onto the substrate as a cathode in the bath, the improvement comprising using as the bismuth compound a compound selected from the group consisting of at least one alkali metal bismuth salt of a linear polyhydroxymonocarboxylic acid having at least six carbon atoms, at least one alkali metal bismuthyl compound of glucono-delta-lactone, and mixtures thereof.
Claim 3
Dependent Claim
15 words
The method of claim 1 wherein the bismuth compound is an alkali metal bismuthyl gluconate.
Claim 4
Dependent Claim
27 words
The method of claim 2 wherein the alkali metal bismuthyl gluconate is selected from the group consisting of potassium bismuthyl trigluconate, sodium bismuthyl trigluconate and mixtures thereof.
Claim 5
Dependent Claim
15 words
The method of claim 3 wherein the alkali metal bismuthyl gluconate is potassium bismuthyl trigluconate.
Claim 6
Dependent Claim
15 words
The method of claim 3 wherein the alkali metal bismuthyl gluconate is sodium bismuthyl trigluconate.
Claim 7
Dependent Claim
22 words
The method of claim 2 wherein the aqueous alkaline plating bath contains 0.001-0.15 grams/liter of bismuth metal as alkali metal bismuthyl gluconate.
Claim 8
Dependent Claim
15 words
The method of claim 1 wherein tin ions are provided by an alkali metal stannate.
Claim 9
Dependent Claim
13 words
The method of claim 7 wherein said alkali metal stannate is potassium stannate.
Claim 10
Dependent Claim
16 words
The method of claim 1 wherein said tin ions are provided by a stannic oxide sol.
Claim 11
Independent Claim
46 words
A method of electroplating a tin-containing alloy onto a conductive substrate comprising immersing a conductive substrate to be plated into an aqueous alkaline plating bath containing potassium stannate and potassium bismuthyl trigluconate, and electroplating a tin-containing alloy onto the substrate as a cathode in the bath.
Claim 12
Independent Claim
46 words
A method of electroplating a tin-containing alloy onto a conductive substrate comprising immersing a conductive substrate to be plated into an aqueous alkaline plating bath containing potassium stannate and potassium bismuthyl trigluconate, and electroplating a tin-containing alloy onto the substrate as a cathode in the bath.
Claim 13
Independent Claim
48 words
A method of electroplating a tin-containing alloy onto a conductive substrate comprising immersing a conductive substrate to be plated into an aqueous alkaline plating bath containing a stannic oxide sol and potassium bismuthyl trigluconate, and electroplating a tin-containing alloy onto the substrate as a cathode in the bath.
Claim 14
Independent Claim
48 words
A method of electroplating a tin-containing alloy onto a conductive substrate comprising immersing a conductive substrate to be plated into an aqueous alkaline plating bath containing a stannic oxide sol and potassium bismuthyl trigluconate, and electroplating a tin-containing alloy onto the substrate as a cathode in the bath.
Claim 15
Dependent Claim
59 words
An aqueous solution for plating a tin-containing alloy on a conductive substrate which solution comprises tin ions, alkali metal hydroxide, and a compound selected from the group consisting of at least one alkali metal bismuth salt of a linear polyhydroxymonocarboxylic acid having at least six carbon atoms, at least one alkali metal bismuthyl compound of glucono-delta-lactone, and mixtures thereof.
Claim 16
Dependent Claim
59 words
An aqueous solution for plating a tin-containing alloy on a conductive substrate which solution comprises tin ions, alkali metal hydroxide, and a compound selected from the group consisting of at least one alkali metal bismuth salt of a linear polyhydroxymonocarboxylic acid having at least six carbon atoms, at least one alkali metal bismuthyl compound of glucono-delta-lactone, and mixtures thereof.
Claim 17
Dependent Claim
18 words
The aqueous solution of claim 12 wherein said alkali metal bismuth salt is an alkali metal bismuthyl gluconate.
Claim 18
Dependent Claim
28 words
The aqueous solution of claim 13 wherein said alkali metal bismuthyl gluconate is selected from the group consisting of potassium bismuthyl trigluconate, sodium bismuthyl trigluconate and mixtures thereof.
Claim 19
Dependent Claim
16 words
The aqueous solution of claim 14 wherein said alkali metal bismuthyl gluconate is potassium bismuthyl trigluconate.
Claim 20
Dependent Claim
16 words
The aqueous solution of claim 14 wherein the alkali metal bismuthyl gluconate is sodium bismuthyl trigluconate.
Claim 21
Dependent Claim
19 words
The aqueous solution of claim 13 which comprises from 0.001-0.15 grams/liter of bismuth metal as alkali metal bismuthyl gluconate.
Claim 22
Dependent Claim
17 words
The aqueous solution of claim 12 wherein said tin ions are provided by an alkali metal stannate.
Claim 23
Dependent Claim
14 words
The aqueous solution of claim 18 wherein said alkali metal stannate is potassium stannate.
Claim 24
Dependent Claim
17 words
The aqueous solution of claim 12 wherein said tin ions are provided by a stannic oxide sol.
Claim 25
Dependent Claim
21 words
An aqueous solution for plating a tin-containing alloy on a conductive substrate which solution comprises potassium stannate and potassium bismuthyl trigluconate.
Claim 26
Dependent Claim
21 words
An aqueous solution for plating a tin-containing alloy on a conductive substrate which solution comprises potassium stannate and potassium bismuthyl trigluconate.
Claim 27
Dependent Claim
23 words
An aqueous solution for plating a tin-containing alloy on a conductive substrate which solution comprises a stannic oxide sol and potassium bismuthyl trigluconate.
Claim 28
Dependent Claim
23 words
An aqueous solution for plating a tin-containing alloy on a conductive substrate which solution comprises a stannic oxide sol and potassium bismuthyl trigluconate.
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) | 1982-07-23 | 1983-01-22 | 1983-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-07-23 | 1987-01-22 | 1987-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-07-23 | 1991-01-22 | 1991-07-24 | $7700.00 | Window Closed / Lapsed |