Method of coating a surface of a fuel cell plate
A method of coating a surface of a fuel cell plate is disclosed herein, and involves forming a sol gel mixture by mixing a weak acid and a composition including at least two metal oxide precursors. One of the metal oxide precursors is configured to be hydrolyzed by the weak acid to form a mixed metal oxide framework with an other of the metal oxide precursors having at least one organic functional group that is not hydrolyzed by the weak acid. The mixture is applied to the surface, and is condensed by exposure to air at least one predetermined temperature and for a predetermined time. The sol gel mixture is immersed in water at a predetermined temperature and for a predetermined time to form a porous, hydrophilic, and conductive film on the surface.
1. A method of coating a surface of a fuel cell plate, the method comprising:
forming a sol gel mixture by mixing a weak acid and a composition including at least two metal oxide precursors, one of the metal oxide precursors configured to be hydrolyzed by the weak acid to form a mixed metal oxide framework with an other of the metal oxide precursors having at least one organic functional group that is not hydrolyzed by the weak acid;
applying the sol gel mixture to the surface of the fuel cell plate;
condensing the sol gel mixture by exposure to air at at least one predetermined temperature for a predetermined time; and
immersing the sol gel mixture in water at a predetermined temperature for a predetermined time to form a porous, hydrophilic, and conductive film on the surface of the fuel cell plate.
2. The method as defined in claim 1 wherein the at least one organic functional group is selected from the group consisting of amides, acrylics, epoxides, alkylureas and combinations thereof.
3. The method as defined in claim 1 , further comprising pretreating the surface of the fuel cell plate via a surface etching process, an electroplating process, or a combination thereof.
4. The method as defined in claim 1 wherein the at least two metal oxide precursors are selected from the group consisting of precursors of: silicon dioxide, titanium dioxide, tin dioxide, tantalum oxide, hafnium dioxide, zirconium dioxide, niobium dioxide, molybdenum oxide, iridium oxide, ruthenium oxide, and aluminum oxide.
5. The method as defined in claim 1 wherein the weak acid is selected from the group consisting of acetic acid, phosphoric acid, citric acid, boric acid, and combinations thereof.
6. The method as defined in claim 1 wherein the weak acid is acetic acid, wherein the other of the metal oxide precursors having the at least one organic functional group is N-(triethoxysilypropyl)urea, wherein the one of the metal oxide precursors configured to be hydrolyzed by the weak acid is titanium tetraisopropoxide, and wherein the sol gel mixture is accomplished by:
mixing a predetermined amount of acetic acid and N-(triethoxysilypropyl)urea in methanol, thereby generating a solution; and
adding a predetermined amount of titanium tetraisopropoxide to the solution, thereby forming a titanium dioxide-silicon dioxide sol gel mixture.
7. The method as defined in claim 1 wherein immersing activates the sol gel mixture, and wherein prior to immersing, the method further comprises drying the fuel cell plate having the suspension applied thereto.
8. The method as defined in claim 7 wherein drying the fuel cell plate having the sol gel mixture applied thereto is accomplished by:
exposing the fuel cell plate to ambient air for a predetermined amount of time; and
thereafter exposing the fuel cell plate to a temperature higher than that of the ambient air for an other predetermined amount of time.
9. The method as defined in claim 8 wherein the higher temperature that the fuel cell plate is exposed to ranges from about 80° C. to about 200° C.
10. The method as defined in claim 8 wherein the predetermined temperature of the water ranges from about 50° C. to about 100° C.