Plug-in connector and semi-finished product made from an aluminum alloy strip

Abstract

A plug-in connector and a semi-finished product include a strip of an aluminum alloy and at least one bonding layer of a copper/tin alloy electrolytically applied directly onto the aluminum alloy strip. The bonding layer has a thickness of at most 50 nm. A further metal layer or alloy layer is applied onto the bonding layer.

Claims

1. A plug-in connector, comprising: a strip of an aluminum alloy; at least one bonding layer of a copper/tin alloy electrolytically applied directly onto said aluminum alloy strip, said bonding layer having a thickness of at most 50 nm; and a further metal layer or alloy layer applied onto said bonding layer.

2. The plug-in connector according to claim 1, wherein said copper/tin alloy contains Cu.sub.3Sn or Cu.sub.6Sn.sub.5.

3. The plug-in connector according to claim 1, wherein said copper/tin alloy is formed of Cu.sub.3Sn or of Cu.sub.6Sn.sub.5 together with unavoidable impurities.

4. The plug-in connector according to claim 1, wherein said bonding layer has grains with a grain size in a range of from 10 to 30 nm.

5. The plug-in connector according to claim 1, wherein said aluminum alloy strip contains at least 80 wt % aluminum.

6. The plug-in connector according to claim 1, wherein said aluminum alloy strip contains at least 90 wt % aluminum.

7. The plug-in connector according to claim 1, wherein said aluminum alloy strip contains at least 95 wt % aluminum.

8. The plug-in connector according to claim 1, wherein said further metal layer or alloy layer contains a metal or an alloy selected from the group consisting of silver, silver/tin, silver/antimony, gold, gold/cobalt, copper, nickel, nickel/phosphorus, nickel/tungsten, indium, lead, palladium/nickel, tin, tin/lead and zinc.

9. A semi-finished product for producing a plug-in connector, the semi-finished product comprising: a strip of an aluminum alloy; at least one bonding layer of a copper/tin alloy electrolytically applied directly onto said aluminum alloy strip, said bonding layer having a thickness of at most 50 nm; and a further metal layer or alloy layer applied onto said bonding layer.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 is a diagrammatic, longitudinal-sectional view of a coated aluminum alloy with a bonding layer and a further metal layer or alloy layer; and

(2) FIG. 2 is a longitudinal-sectional view according to FIG. 1 with further metal layers or alloy layers.

DETAILED DESCRIPTION OF THE INVENTION

(3) Referring now in detail to the figures of the drawings, which reflect only the sequence of the layers but provide no information about the individual layer thicknesses, and first, particularly, to FIG. 1 thereof, there is seen a strip 1 of an aluminum alloy. A bonding layer 2 follows directly on the aluminum alloy strip 1. The bonding layer 2 is formed, for example, of Cu.sub.3Sn. A top layer is formed by a further metal layer or alloy layer 3. The further metal layer or alloy layer 3 is, for example, a solderable tin layer.

(4) The formation of the alloy of the bonding layer 2 may take the form of a sequence of electrolytic baths.

(5) FIG. 2 shows an embodiment according to FIG. 1, in which there are three further metal layers or alloy layers 3, 3a, 3b above the bonding layer 2. The following may be mentioned as an example of the layers: a bonding layer 2 of a copper/tin alloy with a thickness of 30 nm is applied onto a strip with a width of 40 mm and a thickness of 0.5 mm of an aluminum/magnesium alloy having 3 wt % magnesium, a first further metal layer or alloy layer 3 of copper with a thickness of 100 nm is applied thereon, a second further metal layer or alloy layer 3a of nickel with a thickness of 0.5 m or more is applied thereon, and a third further metal layer or alloy layer 3b of tin with a thickness of 2 m is applied thereon as the surface layer. The strip which is coated in this way constitutes a semifinished product for further processing. For example, plug-in connectors may be produced therefrom. The third further metal layer or alloy layer 3b is suitable for the production of a solder connection.

(6) In order to produce the coating, the so-called immersion depth method is used for example, in which only that region of the strip which is to be coated is immersed in a coating bath. The other region of the strip remains without coating. The strip passes through a plurality of coating baths for coating with a copper/tin alloy, followed by a bath for coating with copper, then a further bath for coating with nickel, and thereafter a final bath for coating with tin. The residence time and/or the current strength and current density in the respective bath is/are adapted so that a predetermined layer thickness is achieved. Required cleaning steps are added before or between and after the individual baths.