Tin coated electrical connector

• US 5,780,172 A
• Filed: 06/03/1996
• Issued: 07/14/1998
• Est. Priority Date: 12/18/1995
• Status: Expired due to Term

• Current Assignee: GBC Metals LLC
• Original Assignee: OLIN Corporation
• Inventors: Chen, Szuchain, Khan, Abid A., Fister, Julius C.
• Primary Examiner(s): Zimmerman, John J.
• Assistant Examiner(s): LA VILLA, MICHAEL EUGENE
• Application Number:
  US08/657,211
• Time in Patent Office: 771 Days
• Field of Search: 428/646, 428/615, 428/655, 428/668, 428/669, 428/671, 428/674, 428/675, 428/676, 428/678, 428/680, 428/647, 427/372.2, 439/886, 439/887
• US Class Current: 428/647
• CPC Class Codes: B32B 15/01 all layers being exclusively metallic making layered metal workpieces by pressure cladding B23K20/22; making coatings with a metallic material characterised by its composition C23C30/00
• CPC Class Codes: H01R 13/03 characterised by the material, e.g. plating, or coating materials
• CPC Class Codes: Y10S 428/926 Thickness of individual layer specified
• CPC Class Codes: Y10T 428/12715 Next to Group IB metal-base component
• CPC Class Codes: Y10T 428/12903 Cu-base component
• CPC Class Codes: Y10T 428/12944 Ni-base component

Abstract

An electrical conductor has a copper base substrate coated with a tin base coating layer. To inhibit the diffusion of copper from the substrate into the coating layer and the consequential formation of a brittle tin/copper intermetallic, a barrier layer is interposed between the substrate and the coating layer. This barrier layer contains from 10% to 70%, by weight, of nickel and is preferably predominantly comprised of copper. In one embodiment, an intermetallic layer selected from the group (Cu--Ni)₃ Sn, (Cu--Ni)₆ Sn₅, Cu₃ Sn, Cu₆ Sn₅ is disposed between the barrier layer and the tin base coating layer.

Claims

1. A composite material, comprising:

a copper or a copper base alloy substrate;

a coating layer consisting of tin or a tin base alloy overlying a portion of said substrate; and

an electroplated barrier layer interposed between said substrate and said coating layer directly contacting said coating layer, said barrier layer being predominantly copper and containing from 25% to 40%, by weight, of nickel and having a thickness of from 0.2 micron to 2.5 microns.

2. The composite material of claim 1 wherein said barrier layer further contains at least one element selected from the group consisting of tin, cobalt, iron and mixtures thereof.

3. The composite material of claim 2 wherein said coating layer includes particulate selected from the group consisting of silicon carbide, aluminum oxide, tungsten carbide, molybdenum disulfide and polytetrafluoroethylene.

4. The composite material of claim 2 wherein an intermetallic layer is disposed between said barrier layer and said coating layer.

5. The composite material of claim 4 wherein said intermetallic layer is selected from the group consisting of (Cu--Ni)₃ Sn, (Cu--Ni)₆ Sn₅, Cu₃ Sn, Cu₆ Sn₅ and mixtures thereof.

6. The composite material of claim 5 wherein said intermetallic layer has a thickness of from 100 angstroms to 10,000 angstroms.

7. A composite material, comprising:

a copper or a copper base alloy substrate;

a coating layer consisting of tin or a tin base alloy overlying a portion of said substrate; and

a barrier interposed between said substrate and said coating layer and in direct contact with said coating layer, said barrier being a plurality of different metal or metal alloy constituent layers at least one of constituent layers being copper base and in direct contact with said coating layer, wherein said barrier has a thickness of from 0.2 micron to 5 microns.

8. The composite material of claim 7 wherein a first constituent layer that is selected from the group consisting of nickel, cobalt, nickel base alloys and cobalt base alloys is adjacent to said substrate and a second constituent layer that is copper base is in direct contact with both said first constituent layer and with said coating layer.

9. The composite material of claim 7 wherein a first constituent layer is adjacent to said substrate a second constituent layer is adjacent to both said first constituent layer and a third constituent layer and a fourth constituent layer is both disposed between said third constituent layer and said coating layer and in direct contact with said coating layer wherein said first and said third constituent layers are nickel base and said second and said fourth constituent layers are copper base.

10. The composite material of claim 9 further including a fifth constituent layer that is tin base and disposed between said second constituent layer and said third constituent layer.

11. The composite of claim 9 wherein a fifth constituent layer selected from the group consisting of silver, silicon, aluminum, zinc, iron, chromium, manganese, cobalt, vanadium, indium and base alloys thereof is disposed between said second constituent layer and said third constituent layer.

12. The composite material of claim 8 wherein said first constituent layer is in direct contact with said substrate and said second constituent layer is in direct contact with both said first constituent layer and said coating layer.

13. The composite material of claim 12 wherein said barrier has a thickness of between 0.2 micron and 5 microns and the thickness of said second constituent layer is effective to form a barrier composition that is from 25% to 50%, by weight, of copper.

14. The composite of claim 9 wherein said first constituent layer is in direct contact with said substrate, said second constituent layer is in direct contact with both said first constituent layer and said third constituent layer and said fourth constituent layer is in direct contact with both said third constituent layer and said coating layer.

15. The composite material of claim 14 wherein said barrier has a thickness of between 0.2 micron and 5 microns and the combined thickness of said second constituent layer and said fourth constituent layer is effective to form a barrier composition that is from 25% to 50%, by weight, of copper.