A bipolar plate has a multi-layered structure including an inner metallic layer and at least one outer metallic, corrosion-resistant layer splatted, embedded, diffused and interlocked into the inner metallic layer.
1. A method of producing a metallic bipolar plate comprising the steps of:
providing a plurality of metallic particles with high kinetic energy, the metallic particles being selected from metals or metal alloys exhibiting anti-corrosion characteristics;
impinging the highly energized metallic particles against a metal substrate at high velocities, thereby flattening, embedding, diffusing, and interlocking the metallic particles with the metal substrate in a boundary region thereof, thereby forming a metallic corrosion-resistant layer within the boundary region of the metal substrate; and
reducing a temperature gradient by simultaneously forming the metallic corrosion-resistant layer within boundary regions on opposite faces of the metallic substrates, thereby forming corrosion-resistant metallic boundary regions.
2. The method of claim 1 , wherein the corrosion-resistant metallic boundary layer is formed using a thermal spray technique or a cold gas dynamic technique.
3. The method of claim 1 , wherein the metallic particles are selected from the group consisting of nickel-based alloys, carbide-based alloys and a combination thereof.
4. The method of claim 3 , wherein the combination of the nickel-based alloys and carbide-based alloys are predominantly carbide-based alloys.
5. The method of claim 1 , wherein the corrosion-resistant metallic layer is about 0.008–0.010 inch thick.
6. The method of claim 1 , further comprising forming a plurality gas conveying channels within the corrosion-resistant metallic boundary regions of the metallic substrate.
7. The method of claim 6 , wherein the gas conveying channels each have a V-shaped cross-section, the method further comprising the steps of arranging the gas conveying channels on a first face to guide oxygen in a vertical direction, thereby evacuating water from one of the corrosion-resistant metallic boundary regions under gravity, and arranging the gas conveying channels on the opposite face to guide hydrogen in a horizontal zig-zag configuration, and providing projections in each of the gas conveying channels.
8. The method of claim 1 , wherein the metal substrate is a metal having a low electrical resistance selected from the group consisting of aluminum, cast iron, steel, aluminum alloys, zinc, magnesium, magnesium alloys and a combination of these.
9. The method of claim 1 , wherein the step of simultaneously forming the metallic corrosion-resistant layer within the boundary regions on the opposite faces of the metallic substrate prevents deformation of the bipolar plate.