Method of reducing corrosion of silver containing surfaces

• US 7,575,665 B2
• Filed: 04/28/2005
• Issued: 08/18/2009
• Est. Priority Date: 04/28/2005
• Status: Active Grant

• Current Assignee: Aptiv Technologies AG (Aptiv PLC)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Harrington, Charles R., Aukland, Neil R.
• Primary Examiner(s): Wong; Edna
• Application Number:
  US11/116,509
• Publication Number:
  US 20060246313A1
• Time in Patent Office: 1,573 Days
• Field of Search: 205/238, 205/316, 205/261, 205/263
• US Class Current: 205/238
• CPC Class Codes: C25D 9/06 by anodic processes
• CPC Class Codes: Y10T 428/12535 with additional, spatially distinct nonmetal component
• CPC Class Codes: Y10T 428/12896 Ag-base component

Abstract

Described is a method of reducing corrosion of a silver-containing surface comprising electro-depositing a layer of an iodine-containing material on the silver-containing surface at a charge density of about 80 mA*s (milliamps second)/cm² or less. Also described is an electrical contact also produced by the method.

Claims

1. A method of reducing corrosion of a silver-containing surface comprising electro-depositing a layer of an iodine-containing material on said silver-containing surface at a charge density of about 80 mA*s (milliamp second)/cm² or less, wherein the electro-depositing said layer of said iodine-containing material comprises using an aqueous iodine solution having an iodide ion concentration of 3.0×

10<sup>−

3</sup> to 3.0×

10<sup>−

2</sup> mole/L.

2. The method of claim 1 wherein said charge density is at or below about 40 mA*s/cm².

3. The method of claim 1 wherein said iodine-containing material comprises a contact resistance of about 10 mΩ

(milliohms) or less at 1N contact force after exposure to temperatures below about 200°

C.

4. The method of claim 1 wherein said iodine-containing material comprises a contact resistance of about 100 mΩ

(milliohms) or less at 1N contact force after exposure to temperatures below about 200°

C.

5. The method of claim 1 wherein said iodine-containing material comprises a light gray color.

6. The method of claim 1 wherein the layer of the iodine-containing material has a thickness sufficient to cover the surface of said silver-containing surface.

7. The method of claim 1 wherein said aqueous iodine solution comprises KI.

8. A method as set forth in claim 1 wherein the iodine-containing material is electrodeposited to produce a layer consisting essentially of silver iodide over said silver-containing surface.

9. A method comprising:

providing an electrical contact comprising a base metal and a conductive silver-containing layer coated on the base metal; and

electrodepositing a layer of an iodine-containing material on said silver-containing layer at a charge density of 80 mA* s/cm² or less, wherein said iodine-containing material is electrodeposited using an aqueous iodine solution comprising an iodide ion concentration of 3.0×

10<sup>−

3</sup> to 3.0×

10<sup>−

2</sup> mole/L, the electrodepositing being conducted for a sufficient time so that said iodine-containing material has a contact resistance at 1 N force of about 100 mΩ

or less after exposure to temperatures of about 200°

C or less.

10. A method as set forth in claim 9 wherein the iodine-containing material is electrodeposited to produce a layer consisting essentially of silver iodide over said silver-containing layer.