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A process for continuous nickel plating of an aluminum conductor, by electrolytically pre-treating the aluminum conductor to improve adherence of a nickel coat thereon by passing the aluminum conductor through a pre-treating bath in which is disposed an electrode connected to a first current source

A process for continuous nickel plating of an aluminum conductor, by electrolytically pre-treating the aluminum conductor to improve adherence of a nickel coat thereon by passing the aluminum conductor through a pre-treating bath in which is disposed an electrode connected to a first current source at a first voltage, for supplying to the aluminum conductor a pre-treating current, then electrolytically plating the pre-treated aluminum conductor with nickel in a plating bath in which is disposed an anode connected to a second current source at a second voltage, in which a nickel coat is deposited on the conductor by action of a nickel plating current I n . At least the nickel plating current I n is transmitted to the conductor through a mechanical electrical contact which contacts the conductor between the pre-treating bath and the plating bath, the pre-treating improving the contact properties of the conductor sufficient to permit the transmitting through the mechanical electrical conductor.

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1. A process for continuous nickel plating of an aluminum conductor, comprising the steps of:electrolytically pre-treating the aluminum conductor to improve adherence of a nickel coat thereon by passing the aluminum conductor through a pre-treating bath in which is disposed an electrode connected to

1. A process for continuous nickel plating of an aluminum conductor, comprising the steps of:electrolytically pre-treating the aluminum conductor to improve adherence of a nickel coat thereon by passing the aluminum conductor through a pre-treating bath in which is disposed an electrode connected to a first current source at a first voltage, for supplying to the aluminum conductor a pre-treating current;electrolytically plating the pre-treated aluminum conductor with nickel in a plating bath in which is disposed an anode connected to a second current source at a second voltage, in which a nickel coat is deposited on the conductor by action of a nickel plating current I n , andtransmitting at least the nickel plating current I n to the conductor through a mechanical electrical contact which contacts the conductor between the pre-treating bath and the plating bath,wherein said pre-treating improves contact properties of the conductor sufficient to permit the transmitting through the mechanical electrical conductor. 2. The process according to claim 1, wherein the pre-treatment step comprises an activation in a strong acid or alkaline bath to enable fast dissolution of surface oxides. 3. The process according to claim 1, wherein the pre-treatment step comprises a pre-nickel plating step to coat the aluminum conductor with a primary nickel deposit. 4. The process according to claim 3, wherein the equivalent average thickness of the said primary nickel deposit is less than about 0.1 μm. 5. The process according to claim 1, wherein the pre-treatment step comprises an activation in a strong acid or alkaline bath to enable fast dissolution of surface oxides and a pre-nickel plating step in a pre-nickel plating bath that coats the aluminum conductor with a primary nickel deposit, and wherein the pre-nickel plating step and the activation step are done jointly and electrolytically with a liquid current connection. 6. The process according to claim 5, wherein the compositions of the activation bath and the pre-nickel plating bath are substantially the same. 7. The process according to claim 5, wherein the equivalent average thickness of said primary nickel deposit is less than about 0.1 μm. 8. The process according to claim 1, wherein the pre-treatment step comprises an activation in a strong acid or alkaline bath to enable fast dissolution of surface oxides and a pre-nickel plating step in which the aluminum conductor is coated with a primary nickel deposit, and wherein the pre-nickel plating step and the activation step A are done simultaneously in the same bath. 9. The process according to claim 8, wherein the equivalent average thickness of said primary nickel deposit is less than about 0.1 μm. 10. The process according to claim 1, wherein the mechanical contact is immersed in an optionally cooled liquid. 11. The process according to claim 1, wherein said mechanical electric contact comprises at least one mechanical rolling contact means. 12. The process according to claim 1, wherein several aluminum conductors are treated simultaneously. 13. The process according to claim 1, wherein the aluminum conductor is made of an alloy selected from the group consisting of AA 1370, AA 1110 and AA 6101 according to the nomenclature of the Aluminum Association. 14. A process for manufacturing an aluminum electrical cable comprising:providing an elementary wire or strand as said aluminum conductor;nickel plating said wire or strand using the process according to claim 1;making said cable using said at least one nickel plated elementary wire or strand. 15. The process according to claim 1, wherein said aluminum conductor is an aluminum strip or aluminum tube. 16. The process according to claim 1, wherein said aluminum conductor is a composite aluminum product comprising a base part and at least one clad aluminum alloy layer. 17. The process according to claim 16, wherein the clad alloy layer comprises a wetting agent. 18. The process according to claim 17, wherein the wetting agent is selected from the group consisting of lead, bismuth, lithium, antimony, tin, silver, thallium and any mixture thereof. 19. The process according to claim 17, wherein the clad alloy layer comprises between 0.01 and 1 wt. % of wetting agent. 20. The process according to claim 16, wherein the clad alloy layer comprises an aluminum-silicon alloy. 21. The process according to claim 1, wherein the nickel plating step is performed using a nickel plating bath containing a compound of a wetting agent, so as to deposit a nickel coat containing a wetting agent onto the aluminum conductor. 22. The process according to claim 21, wherein compound is selected from the group consisting of the acetates, citrates, sulfamates, fluoborates, lactates, oxides and mixtures thereof. 23. The process according to claim 22, wherein said aluminum conductor is a composite aluminum product comprising a base part and at least one clad aluminum alloy layer. 24. The process according to claim 23, wherein the clad alloy layer comprises an aluminum-silicon alloy. 25. The process according to claim 23, wherein the clad alloy layer comprises a wetting agent. 26. The process according to claim 25, wherein the wetting agent is selected from the group consisting of lead, bismuth, lithium, antimony, tin, silver, thallium and any mixture thereof. 27. The process according to claim 25, wherein the clad alloy layer comprises between 0.01 and 1 wt. % of wetting agent. 28. A process for manufacturing an assembled product comprising the steps of:providing as said aluminum conductor a composite aluminum product comprising a base part and at least one clad aluminum alloy layer; andnickel plating said composite product according to the process of claim 1. 29. The manufacturing process according to claim 28, wherein the clad alloy layer comprises a wetting agent. 30. The manufacturing process according to claim 29, wherein the wetting agent is selected from the group consisting of lead, bismuth, lithium, antimony, tin, silver, thallium and mixtures thereof. 31. The manufacturing process according to claim 29, wherein the clad alloy layer comprises between 0.01 and 1 wt. % of wetting agent. 32. The manufacturing process according to claim 28, wherein the clad alloy layer comprises an aluminum-silicon alloy. 33. The manufacturing process according to claim 28, wherein said composite product is in the form of a strip or a tube. 34. The manufacturing process according to claim 28, wherein the nickel plating is performed using a nickel plating bath containing a compound of a wetting agent, so as to deposit a nickel coat containing a wetting agent onto the aluminum conductor. 35. The manufacturing process according to claim 34, wherein the compound is selected from the group consisting of acetates, citrates, sulfamates, fluoborates, lactates, oxides and mixtures thereof. 36. The manufacturing process according to claim 34, wherein the clad alloy layer comprises a wetting agent. 37. The manufacturing process according to claim 36, wherein the wetting agent is selected from the group consisting of lead, bismuth, lithium, antimony, tin, silver, thallium and any mixture thereof. 38. The manufacturing process according to claim 36, wherein the clad alloy layer comprises between 0.01 and 1 wt. % of wetting agent. 39. The manufacturing process according to claim 28, wherein the assembled product is a heat exchanger. 40. The manufacturing process according to claim 28, further comprising brazing said composite product.