US4270986A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for soldering aluminum
Assignee: Sifco Industries Inc
•
Filing: 1979-07-12
•
Granted: 1981-06-02
•
Expires: 1999-07-12
Abstract
Abstract A method and apparatus for soldering aluminum are disclosed. According to the method, the aluminum surface to be soldered is subject to conventional cleaning, then electrolytic cleaning and electrolytic etching, followed by electroplating a very thin layer of nickel on the cleaned and etched surface. The electrolytic cleaning, etching, and plating operations are all carried out by the use of a brush plating tool having an insulated handle portion, to one end of which a wire electrode encased in a porous covering composed of polyester felt is secured. After the plating has been completed, the surface may be soldered with conventional soft solders and non-corrosive fluxes, using conventional soldering techniques.
Inventors
- 👤 Gary W. Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:32
CPC Classifications
B; B23; B23K; B23K1/00; B23K1/19; B23K1/20; B23K1/206; B23K35/00; B23K35/001; B23K35/002; C; C25; C25D; C25D5/00; C25D5/04; C25D5/06; C25D5/34; C25D5/42; C25D5/44; C25F; C25F7/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
120 words
A method of soldering aluminum with soft solder which includes the steps of removing surface soil from the aluminum surfaces to be soldered, subjecting the surfaces to be soldered to an electrocleaning operation by making the surface the cathode in an electrolytic circuit embodying an alkaline electrolyte, electroetching the electrocleaned surface by making the surface the anode in an electrolytic circuit embodying an acid electrolyte and brush electroplating a layer of nickel having a thickness of from about 0.000030 inch to about 0.000050 inch on the previously cleaned and etched aluminum surfaces and thereafter soldering the surfaces by applying a soft solder and a non-corrosive flux thereto, and heating the solder sufficiently to fuse the same on the nickel-plated surfaces.
Claim 2
Independent Claim
120 words
A method of soldering aluminum with soft solder which includes the steps of removing surface soil from the aluminum surfaces to be soldered, subjecting the surfaces to be soldered to an electrocleaning operation by making the surface the cathode in an electrolytic circuit embodying an alkaline electrolyte, electroetching the electrocleaned surface by making the surface the anode in an electrolytic circuit embodying an acid electrolyte and brush electroplating a layer of nickel having a thickness of from about 0.000030 inch to about 0.000050 inch on the previously cleaned and etched aluminum surfaces and thereafter soldering the surfaces by applying a soft solder and a non-corrosive flux thereto, and heating the solder sufficiently to fuse the same on the nickel-plated surfaces.
Claim 3
Dependent Claim
17 words
A method according to claim 1, wherein the alkaline electrolyte comprises a water solution of sodium hydroxide.
Claim 4
Dependent Claim
19 words
A method according to claim 1 or claim 2, wherein the acid electrolyte comprises a solution of hydrochloric acid.
Claim 5
Dependent Claim
14 words
A method according to claim 1 or claim 2, wherein the flux comprises rosin.
Claim 6
Dependent Claim
30 words
A method according to claim 1 or claim 2, wherein the brush plating is carried out with an electrolyte comprising a solution containing nickel sulfate, citric acid, and nickel formate.
Claim 7
Dependent Claim
28 words
A method according to claim 1 or claim 2, wherein the solder contains from about 30% to about 50% tin and from about 70% to about 50% lead.
Claim 8
Dependent Claim
62 words
A method according to claim 1 or claim 2, wherein the nickel is deposited on the surface by means of a brush-plating operation employing a tool as an anode in the electrolytic circuit, the anode tool having a surface comprising an absorbent layer of felt saturated with the plating electrolyte, the workpiece to be plated constituting the cathode in the electrolytic circuit.
Claim 9
Dependent Claim
19 words
A method according to claim 1 or claim 2, wherein the electroplating is carried out at about 9 volts.
Claim 10
Independent Claim
279 words
A method of soldering aluminum with soft solder which includes the steps of removing surface soil from each aluminum surface to be soldered, subjecting the surface to be soldered to an electrocleaning operation by making the surface the cathode in an electrolytic circuit embodying an alkaline electrolyte and rubbing the surface by a non-conducting absorbent member saturated with the electrolyte during the electrolytic cleaning operation, electroetching the electrocleaned surface by making the surface the anode in an electrolytic circuit embodying an acid electrolyte and rubbing the surface being etched with a non-conducting absorbent member saturated with the acid electrolyte during the electroetching operation, brush electroplating a layer, consisting essentially of nickel and having a thickness of from about 0.000030 to about 0.000050 inch, on the previously cleaned and etched aluminum surface, the surface being rubbed by a non-conducting absorbent member saturated with a nickel plating electrolyte during the plating operation, the nickel layer being sufficiently thick to prevent the formation of an oxide film on the aluminum surface for a period of at least several hours, and thereafter soldering the surface by applying a soft solder and a non-corrosive flux to the nickel plated surface and heating the solder sufficiently to fuse the same to the nickel plated surface of the underlying aluminum, the soldering operation producing an alloy of nickel and solder that extends substantially to the underlying surface of the aluminum, the percentage of nickel in the alloy layer being greater in the portions thereof near the aluminum surface than in the portions thereof at greater distances from the aluminum surface, the alloy layer inhibiting the occurrence of interfacial corrosion in soldered joints produced by the method.
Claim 11
Independent Claim
279 words
A method of soldering aluminum with soft solder which includes the steps of removing surface soil from each aluminum surface to be soldered, subjecting the surface to be soldered to an electrocleaning operation by making the surface the cathode in an electrolytic circuit embodying an alkaline electrolyte and rubbing the surface by a non-conducting absorbent member saturated with the electrolyte during the electrolytic cleaning operation, electroetching the electrocleaned surface by making the surface the anode in an electrolytic circuit embodying an acid electrolyte and rubbing the surface being etched with a non-conducting absorbent member saturated with the acid electrolyte during the electroetching operation, brush electroplating a layer, consisting essentially of nickel and having a thickness of from about 0.000030 to about 0.000050 inch, on the previously cleaned and etched aluminum surface, the surface being rubbed by a non-conducting absorbent member saturated with a nickel plating electrolyte during the plating operation, the nickel layer being sufficiently thick to prevent the formation of an oxide film on the aluminum surface for a period of at least several hours, and thereafter soldering the surface by applying a soft solder and a non-corrosive flux to the nickel plated surface and heating the solder sufficiently to fuse the same to the nickel plated surface of the underlying aluminum, the soldering operation producing an alloy of nickel and solder that extends substantially to the underlying surface of the aluminum, the percentage of nickel in the alloy layer being greater in the portions thereof near the aluminum surface than in the portions thereof at greater distances from the aluminum surface, the alloy layer inhibiting the occurrence of interfacial corrosion in soldered joints produced by the method.
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) | 1984-06-01 | 1984-12-01 | 1985-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-01 | 1988-12-01 | 1989-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-01 | 1992-12-01 | 1993-06-02 | $7700.00 | Window Closed / Lapsed |