Electrical contact including corrosion-resistant coating
In accordance with one embodiment, an electrical contact has a mating end and a mounting end. The electrical contact includes an electrically conductive base, and a multi-layered coating disposed on an outer surface of the base at the mating end. The multi-layered coating can include a metallic layer of a noble metal or alloy thereat: a layer of anti-tarnish material disposed on the metallic layer, and a lubricant layer disposed on the layer of anti-tarnish material, the lubricant effective to seal at least some wear regions created in the layer of anti-tarnish material due to micromotion of the mating end in use.
1. An electrical contact having a mating end and a mounting end, the electrical contact comprising:
an electrically conductive base; and
a multi-layered coating disposed on an outer surface of the base at the mating end, the multi-layered coating including:
a metallic layer comprising a silver layer and a gold layer disposed directly on the silver layer; and
a layer of lubricant disposed directly on the gold layer, wherein the layer of lubricant is effective to seal at least some wear regions created on the metallic layer due to micromotion of the mating end in use, wherein the layer of lubricant comprises a perfluorinated compound.
2. The electrical contact of claim 1 , wherein the gold layer is disposed on an outer surface of the silver layer.
3. The electrical contact of claim 2 , wherein the layer of lubricant is disposed on an outer surface of the gold layer.
4. The electrical contact of claim 1 , wherein the base comprises a substrate made from an electrically conductive material, and an electrically conductive barrier layer disposed between the substrate and the metallic layer.
5. The electrical contact of claim 4 , wherein the barrier layer is made from any one of nickel, tin, aluminum, silver, gold, lead, palladium, and an alloy of palladium.
6. The electrical contact of claim 1 , wherein the perfluorinated compound comprises perfluorinated polyether.
7. The electrical contact of claim 1 , wherein the electrical contact is a power contact.
8. The electric contact of claim 7 , wherein the power contact is configured to support currents of 0-25 A.
9. The electric contact of claim 8 , wherein the power contact is configured to support currents of 0-50 A.
10. The electrical contact of claim 1 , wherein the electrical contact withstands a greater amount of micromotion than conventional mating ends in accordance with industry standard vibration tests as described in EIA-364-28, Standard TP-28E, entitled “Vibration Test Procedure for Electrical Connectors and Sockets.”
11. The electrical contact of claim 10 , wherein the industry standards vibration tests are such that a contact pressure of 650 MPa is applied to the electrical contact with a relative oscillating movement having a frequency of 20 Hz.
12. A method of fabricating a mating end of an electrical contact having an electrically conductive base, the method comprising the steps of:
applying a silver layer onto an outer surface of the base;
applying a gold layer directly onto an outer surface of the silver layer; and
applying a lubricant directly onto an outer surface of the gold layer, wherein the lubricant comprises a perfluorinated compound.
13. The method of claim 12 , wherein the conductive base layer comprises a layer of aluminum or aluminum alloy and an electrically conductive barrier layer disposed on an outer surface of the layer of aluminum or aluminum alloy, and wherein applying the silver layer onto an outer surface of the base comprises applying the silver layer onto the barrier layer.
14. The method of claim 13 , wherein the lubricant further comprises poly alpha olefin.
15. The method of claim 12 , wherein the perfluorinated compound comprises perfluorinated polyether.
16. The method of claim 12 , wherein applying the lubricant directly onto an outer surface of the gold layer comprises applying a solvent that carries the lubricant to the outer surface of the gold layer.
17. The method of claim 16 , further comprising the step of drying the solvent so that the lubricant remains on the outer surface of the gold layer.
18. A method of operating an electrical contact having a mating end comprising a silver layer and a gold layer disposed directly on the silver layer, the method comprising:
contacting the mating end of the electrical contact with a complementary electrical contact; and
sealing a wear region arising on the mating end of the electric contact due to micromotion of the mating end with a layer of lubricant disposed directly on the gold layer, wherein the layer of lubricant comprises a perfluorinated compound.
19. The method of claim 18 , further comprising:
applying the layer of lubricant directly on the gold layer prior to contacting the mating end of the electrical contact with the complementary electrical contact.
20. The method of claim 18 , wherein the layer of lubricant comprises an anti-corrosive agent.
21. The method of claim 18 , further comprising:
causing a current of at least 10 A to flow between the electrical contact and the complementary electrical contact.
22. The method of claim 18 , wherein the perfluorinated compound comprises perfluorinated polyether.