Claims
- 1. A method for manufacturing a first plurality of metal-coated articles, wherein:
- each of said articles has a chemically modified external surface and a contact resistance associated with the external surface;
- associated with the coatings is a resistance to corrosion defined as the expected fraction of articles exhibiting contact resistances below a predetermined threshold after being subjected to a predetermined aging process;
- the method comprises the steps of:
- a) providing a first plurality of metal workpieces, each workpiece comprising a metal substrate and, formed on the substrate, a metal coating which has an external surface, wherein the metal coating comprises a transition metal selected from the group consisting of nickel, cobalt, titanium, chromium, and iron; and
- b) exposing each of said coating external surfaces to a liquid solution of a chemical compound selected from the group consisting of those phosphonic acids, and the salts thereof, which include at least 6 carbon atoms, resulting in a chemically modified coating external surface; and
- the exposing step is carried out such that: i) each of said modified surfaces has a contact resistance of about 50 m.OMEGA. or less; and ii) the resistance of the first plurality of articles to corrosion is increased, as compared to a second plurality of articles nominally identical to the first plurality but not exposed to such a liquid solution.
- 2. The method of claim 1, wherein the transition metal is nickel.
- 3. The method of claim 1, wherein the chemical compound is at least partially fluorinated.
- 4. The method of claim 1, wherein the molecular structure of the chemical compound includes multiple hydrocarbon chains.
- 5. The method of claim 1, wherein the molecular structure of the chemical compound includes at least 6 fluorinated carbon atoms.
- 6. The method of claim 1, wherein the chemical compound is a partially fluorinated alkyl phosphonic acid including at least about 6, but not more than about 14, perfluorinated carbon atoms.
- 7. The method of claim 6, wherein the phosphonic acid has the formula C.sub.8 F.sub.17 SO.sub.2 N(CH.sub.2 CH.sub.3)C.sub.2 H.sub.4 PO(OH).sub.2.
- 8. The method of claim 6, wherein the phosphonic acid has the formula CF.sub.3 (CF.sub.2).sub.11 (CH.sub.2).sub.2 PO(OH).sub.2.
- 9. The method of claim 1, wherein each of said metal coatings further comprises a noble metal layer overlying the transition metal coating, and each said coating external surface is the surface of the corresponding noble metal layer distal the transition metal coating.
- 10. The method of claim 9, wherein each of said noble metal layers is a gold layer.
- 11. The method of claim 10, wherein each gold layer is less than about 0.6 .mu.m thick.
- 12. The method of claim 10, wherein each gold layer is no more than about 0.1 .mu.m thick.
- 13. The method of claim 1, further comprising, before the chemical-compound-exposing step, the step of exposing each said coating external surface to a chromate solution such that the resistance to corrosion is further increased.
- 14. A method for manufacturing a first plurality of metal-coated articles, wherein:
- each of said articles has a chemically modified external surface and a contact resistance associated with the external surface;
- associated with the coatings is a resistance to corrosion defined as the expected fraction of articles exhibiting contact resistances below a predetermined threshold after being subjected to a predetermined aging process;
- the method comprises the steps of:
- a) providing a first plurality of metal workpieces, each workpiece comprising a metal substrate and, formed on the substrate, a metal coating which has an external surface, wherein the metal coating comprises nickel or a nickel alloy;
- b) exposing each of said coating external surfaces to a chromate solution; and
- c) then exposing each of said coating external surfaces to a liquid solution of a partially fluorinated alkyl phosphonic acid which includes at least about 6, but not more than about 14, perfluorinated carbon atoms, resulting in a chemically modified coating external surface; and
- the exposing steps are carried out such that: i) each of said modified surfaces has a contact resistance of about 50 m.OMEGA. or less; and ii) the resistance of the first plurality of articles to corrosion is increased, as compared to a second plurality of articles nominally identical to the first plurality but not exposed to such a liquid solution.
- 15. A method for manufacturing a first plurality of metal-coated articles, wherein:
- each of said articles has a chemically modified external surface and a contact resistance associated with the external surface;
- associated with the coatings is a resistance to corrosion defined as the expected fraction of articles exhibiting contact resistances below a predetermined threshold after being subjected to a predetermined aging process;
- the method comprises the steps of:
- a) providing a first plurality of metal workpieces, each workpiece comprising a metal substrate and, formed on the substrate, a metal coating which has an external surface, wherein the metal coating comprises a transition metal selected from the group consisting of nickel, cobalt, titanium, chromium, and iron; and
- b) exposing each of said coating external surfaces to a liquid solution of a monoester of phosphoric acid or of a salt of such monoester, resulting in a chemically modified coating external surface;
- the monoester belongs to the group which consists of the phosphatidic acids having the general formula ##STR2## wherein n is an integer in the range 10-16; and the exposing step is carried out such that: i) each of said modified surfaces has a contact resistance of about 50 m.OMEGA. or less; and ii) the resistance of the first plurality of articles to corrosion is increased, as compared to a second plurality of articles nominally identical to the first plurality but not exposed to such a liquid solution.
- 16. The method of claim 15, further comprising, before the monoester-exposing step, the step of exposing each said surface to a chromate solution such that the resistance to corrosion is further increased.
- 17. A method for lubricating a surface of a body which comprises a transition metal, transition metal alloy, or aluminum-containing alloy, the method comprising the step of applying to the surface a liquid solution which comprises a chemical compound having the formula
- CF.sub.3 (CF.sub.2).sub.m (CH.sub.2).sub.n PO(OH).sub.2,
- wherein m equals 5, 7, 9, or 11, and n equals 0, 1, or 2.
Parent Case Info
This application is a continuation-in-part of application Ser. No. 07/718,890 filed on Jun. 21, 1991, abandoned.
US Referenced Citations (11)
Non-Patent Literature Citations (1)
Entry |
Plating and Surface Finishing, 76(4), 1989, "Nickel-Phosphorus Alloy As a Low-Cost Electrical Contact Material", C. A. Holden, H. H. Law, C. A. Mattoe and J. Sapjeta, pp. 58-61. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
718890 |
Jun 1991 |
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