Super-hydrophobic composite bipolar plate
A method for making a super-hydrophobic composite bipolar plate including providing a substrate comprising a composite material including carbon, and a surface layer on the substrate, and wherein the surface layer includes silicon and oxygen, and heating the substrate and surface layer to cause moieties including carbon from the substrate to diffuse outwardly through the surface layer so that the moiety is attached to one of the silicon or oxygen.
1. A method for making a fuel cell component, said method comprising:
providing a substrate including a carbon;
depositing a porous surface layer over the substrate, said porous surface layer including silicon and oxygen; and
causing a portion of the carbon in the substrate to diffuse through the porous surface layer and attach to at least one of the silicon or oxygen to produce a hydrophobic surface on the substrate.
2. The method as set forth in claim 1 wherein the substrate includes a base material and a first layer overlying the base material and wherein the first layer includes carbon.
3. The method as set forth in claim 2 wherein the base material includes a metal.
4. The method as set forth in claim 3 wherein the base material includes stainless steel.
5. The method as set forth in claim 2 wherein the first layer includes graphite.
6. The method as set forth in claim 2 wherein the first layer includes carbon black and/or graphite particles mixed with an organic resin.
7. The method as set forth in claim 1 wherein the substrate includes graphite.
8. The method as set forth in claim 1 wherein the porous surface layer includes silicon dioxide.
9. The method as set forth in claim 1 wherein the porous surface layer includes SiO x where 0.1<x<2.0.
10. The method as set forth in claim 1 wherein the porous surface layer includes silicon bonded to oxygen.
11. The method as set forth in claim 1 wherein causing the carbon to diffuse through the porous surface layer includes heating at least a portion of the substrate to a temperature in the range of 90-200° C.
12. The method as set forth in claim 11 wherein the heating includes placing the substrate in an oven.
13. The method as set forth in claim 11 wherein the heating includes exposing at least a portion of the porous surface layer to a laser beam.
14. The method as set forth in claim 11 wherein the heating includes exposing at least a portion of the porous surface layer to an electron beam.
15. The method as set forth in claim 11 wherein the heating includes placing the substrate on a heated plate.
16. The method as set forth in claim 11 wherein the heating includes hot pressing portions of the portions of the porous layer.
17. The method as set forth in claim 1 wherein the substrate includes a gas flow field comprising a plurality of lands and channels and the porous surface layer is over at least a portion of at least one of the lands or channels.
18. The method as set forth in claim 1 wherein causing the carbon to diffuse through the porous surface layer includes selectively heating portions of the substrate.
19. The method as set forth in claim 1 wherein the porous surface layer is only on the lands and not on the channels, and wherein causing the carbon to diffuse through the porous surface layer includes heating the lands of the substrate.
20. The method according to claim 1 wherein the hydrophobic surface is a super-hydrophobic surface having a contact angle greater than 130° C.
21. A method for making a composite bipolar plate for a fuel cell including a surface having portions that are super-hydrophobic, said method comprising:
providing a composite substrate including a material having a hydrocarbon;
depositing a porous surface layer over the substrate, said porous layer including at least one of silicon dioxide, SiO x , where 0.1<x<2.0, or a compound comprising silicon and oxygen; and
heating at least a portion of the substrate so that hydrocarbon moieties diffuse through the surface layer and attach to one of the silicon dioxide, SiO X , or the silicon or oxygen in the compound to provide a super-hydrophobic surface.
22. The method as set forth in claim 21 wherein the substrate includes a plurality of lands and channels and wherein the porous surface layer is only on the lands.
23. The method according to claim 21 wherein the super-hydrophobic surface has a contact angle greater than 130° C.