Granted Patent B2

US 6,866,958 · App. 10/163,393 · Granted Mar 15, 2005

Abstract

Claims (75)

1. A method for manufacturing an electrically conductive fluid distribution element, comprising the steps of:

providing a substrate;

cleaning said substrate with an ion beam; and

depositing an electrically conductive coating on said substrate by physical vapor deposition to a thickness of less than 100 nm,

wherein

said cleaning and said depositing are conducted essentially simultaneously; and

said cleaning comprises removing an oxide layer from said substrate.

2. The method of claim 1 , wherein said cleaning is initiated prior to said depositing and said cleaning continues during said depositing.

3. The method of claim 1 further comprising continuing said cleaning of said substrate at least until said depositing is terminated.

4. The method of claim 3 wherein said cleaning is terminated after said depositing is terminated.

5. The method of claim 1 , wherein said coating is deposited to a thickness of less than 80 nm.

6. The method of claim 1 , wherein said coating has a thickness of 10-20 nm.

7. A method for manufacturing an electrically conductive fluid distribution element, comprising the steps of:

providing a substrate;

cleaning said substrate with an ion beam; and

depositing an electrically conductive coating on said subs rate by physical vapor deposition to a thickness of less than 100 nm,

wherein:

said cleaning and said depositing are conducted essentially simultaneously; and

said electrically conductive coating is deposited to loading of 0.02 to 0.04 mg/cm 2 .

8. The method of claim 1 , wherein said substrate is selected from the group consisting of stainless steel, aluminum, and titanium.

9. The method of claim 1 , wherein said coating comprises a noble metal.

10. The method of claim 9 , wherein said noble metal is selected from the group consisting of Ru, Rh, Pd, Ag, Au, Ir, Pt, Os, and combinations thereof.

11. A method for manufacturing an electrically conductive fluid distribution element, comprising the steps of:

providing a substrate;

cleaning said substrate with an ion beam; and

depositing an electrically conductive coating on said substrate by physical vapor deposition to a thickness of less than 100 nm,

wherein:

said cleaning and said depositing are conducted essentially simultaneously; and

said coating has a contact resistance of 1.5-6.5 milliohms/cm 2 .

12. The method according to claim 1 , wherein said coating comprises a corrosive-resistant coating.

13. The method according to claim 1 , wherein said coating is deposited at a rate of 0.10 nm/s.

14. An electrically conductive fluid distribution element comprising:

a metal substrate; and

an electrically conductive coating disposed on said substrate,

wherein:

said coating has a thickness of less than 80 nm; and

said electrically conductive coating has a loading of 0.02-0.04 mg/cm 2 .

15. An electrically conductive fluid distribution element comprising:

a metal substrate; and

an electrically conductive coating disposed on said substrate,

wherein:

said coating has a thickness of less than 80 nm; an

an outer layer of said coating comprises a noble metal or mixture of noble metals and said coating further comprises an intermediate metal layer of a non-noble corrosive-resistant metal disposed between said substrate and said outer layer; wherein said coating has a smooth surface characterized by a peak-to-valley range of less than 2.5 micrometers.

16. The element of claim 15 , wherein said coating has a contact resistance of 1.5-6.5 milliohms/cm 2 .

17. The element of claim 16 , wherein said substrate is selected from a group consisting of stainless steel, aluminum, and titanium.

18. A fuel cell comprising an electrically conductive fluid distribution element and a membrane electrode assembly;

said membrane electrode assembly including a polymer electrolyte having an anode on one face of said membrane electrolyte and a cathode on an opposite face of said membrane electrolyte; and

said element comprising:

an electrically conductive polymeric substrate; and

an electrically conductive coating disposed on said substrate,

wherein said coating has a thickness of less than 100 nm.

19. A fuel cell comprising an electrically conductive fluid distribution element and a membrane electrode assembly;

said membrane electrode assembly including a polymer electrolyte having an anode on one face of said membrane electrolyte and a cathode on an opposite face of said membrane electrolyte; and

said element comprising:

a conductive foam having external surfaces and internal openings forming through passages through said foam for fluid distribution; and

an electrically conductive metal coating on such external surfaces and optionally on said internal openings,

wherein said coating has a thickness of less than 100 nm.

20. The element of claim 18 , wherein said polymeric substrate is a composite which comprises a polymer and a conductive filler dispersed in said polymer.

21. The element of claim 20 , wherein conductive filler is selected from the group consisting of carbon fibers, graphite fiber, nickel-coated graphite fibers, stainless steel fibers, and combinations thereof.

22. The element of claim 20 , wherein said polymer is selected from the group consisting of silicone, poly-isobutylene, epoxy, vinyl ester, phenolic, polypropylene, ethylene tetrafluoro-ethylene, nylon, rubber modified polypropylene, and mixtures thereof.

23. The element of claim 18 , wherein said coating comprises a noble metal selected from the group consisting of Ru, Rh, Pd, Au, Ag, Ir, Pt, Os, and combinations thereof.

24. The element of claim 19 , wherein said coating comprises a noble metal selected from the group consisting of Ru, Rh, Pd, Ag, Au, Ir, Pt, Os, and combinations thereof.

25. The element of claim 19 , wherein said foam is selected from the group consisting of stainless steel, nickel, aluminum, titanium, and carbon.

26. A method for manufacturing an electrically conductive element, comprising:

providing a substrate;

cleaning said substrate with an ion beam; and

depositing an electrically conductive coating on said substrate by physical vapor deposition to a thickness of less than 100 nm,

wherein:

said cleaning and said depositing are conducted essentially simultaneously; and

said cleaning comprises removing an oxide from said substrate.

27. An electrically conductive element comprising:

an electrically conductive substrate having a surface containing a plurality of grooves and lands, and an electrically conductive coating disposed on said substrate overlying at least said lands,

wherein at least one of the following apply:

(a) said coating has a thickness of less than 100 nm;

(b) said electrically conductive coating has a loading of 0.02-0.04 mg/cm 2 .

Assignments (12)