Claims
- 1. A dimensionally stable electrode comprising:
- a) a substrate defining a cavity, wherein said substrate comprises an interior wall and an exterior surface and wherein said substrate is capable of diffusing metal from the cavity to the exterior surface;
- b) a film covering portions of the exterior surface; and
- c) a means for replenishing said film.
- 2. The electrode as recited in claim 1 wherein the substrate is a metal alloy selected from the group consisting of Cu--Al, Ni--Al, Fe--Al, Cr--Al, Ti--Al, Fe--Cr--Al, Cu--Al--Ag, Cu--Ni--Al, Cu--Al--Mg, and combinations thereof.
- 3. The electrode as recited in claim 1 wherein the film comprises a metal-anion combination selected from the group consisting of metal-carbide, metal-nitride, metal-oxide, metal-boride, metal-sulfide, metal halide, and combinations thereof.
- 4. The electrode as recited in claim 1 wherein the film is replenished while it is in contact with a molten electrolyte.
- 5. The electrode as recited in claim 1 wherein the cavity defines a means for facilitating communication of a fluid with the interior wall.
- 6. The electrode as recited in claim 5 wherein the fluid contains metal selected from the group consisting of zirconium, thorium, titanium, tin, aluminum, yttrium, hafnium, uranium, magnesium, cerium or cesium.
- 7. The electrode as recited in claim 5 wherein the fluid is a salt containing a metal and an anion, said anion selected from the group consisting of fluoride, carbonate, chloride, oxide, and combinations thereof.
- 8. The electrode as recited in claim 5 wherein the fluid is a salt selected from the group consisting of a metal fluoride, a metal carbonate, a metal chloride, a metal oxide, and combinations thereof.
- 9. The electrode as recited in claim 1 wherein the film is an oxide selected from the group consisting of zirconium oxide, thorium oxide, titanium oxide, tin oxide, aluminum oxide, yttrium oxide, hafnium oxide, uranium oxide, magnesium oxide, cerium oxide, cesium oxide, and combinations thereof.
- 10. The electrode as recited in claim 1 wherein said means for replenishing said film comprises:
- a) a metal transport mechanism from the cavity to the external surface; and
- b) a combination of the metal with an anion at the external surface.
- 11. A method for maintaining the dimensions of an anode during electrolysis, comprising:
- a) adapting an interior surface of the anode to form a cavity defining an interior wall so as to receive a fluid containing metal;
- b) facilitating diffusion of the metal from the cavity to an exterior surface of the anode;
- c) forming a metal-containing film on said exterior surface, wherein the diffused metal is a constituent of said formed film; and
- d) maintaining said metal-containing film on said exterior surface while the anode is in use, whereby the dimensions of the anode are maintained.
- 12. The method as recited in claim 11 wherein the metal is present in the metal-containing fluid at a concentration that maintains the chemical activity of the metal in the fluid equal to the chemical activity of the same metal in the anode.
- 13. The method as recited in claim 11 wherein said metal is zirconium, thorium, titanium, tin, aluminum, yttrium, hafnium, uranium, magnesium, or cesium.
- 14. The method as recited in claim 11 wherein the anode is immersed in an electrolyte containing a halogen selected from the group consisting of chlorine, fluorine, and combinations thereof.
- 15. The method as recited in claim 11 wherein the anode contains an alloy selected from the group consisting of Cu--Al, Ni--Al, Fe--Al, Cr--Al, Ti--Al, Fe--Cr--Al, Cu--Al--Ag, Cu--Ni--Al, Cu--Al--Mg, and combinations thereof.
- 16. The method as recited in claim 11 wherein the fluid is a salt containing a metal and an anion, said anion selected from the group consisting of a fluoride, a carbonate, a chloride, an oxide, and combinations thereof.
- 17. The method as recited in claim 11 wherein the film is a compound selected from the group consisting of a metal carbide, a metal nitride, a metal boride, and a metal oxide.
- 18. An electrolysis anode comprising a compound that forms and maintains a magnesium aluminate spinel oxide protective film on an exterior surface of the anode during electrolytic production of magnesium.
- 19. The anode as recited in claim 18 wherein the compound is a magnesium-containing alloy selected from the group consisting of Cu--Al--Mg, Ni--Al--Mg, Fe--Al--Mg, Cr--Al--Mg, Ti--Al--Mg, Fe--Cr--Al--Mg, Cu--Al--Ag--Mg, Cu--Ni--Al--Mg, and combinations thereof.
- 20. An electrolysis anode defining a cavity and comprising a compound that forms a protective film during electrolytic production of aluminum.
- 21. The anode as recited in claim 20 wherein the compound is an alloy selected from the group consisting of Cu--Al, Ni--Al, Fe--Al, Cr--Al, Ti--Al, Fe--Cr--Al, Cu--Al--Ag, Cu--Ni--Al, Cu--Al--Mg, and combinations thereof.
- 22. The anode as recited in claim 20 wherein the protective film is a metal carbide, a metal nitride, a metal boride, or a metal oxide.
CONTRACTUAL ORIGIN OF THE INVENTION
The United States Government has rights in this invention pursuant to Contract Number W-31-109-ENG-38 between the United States Government and Argonne National Laboratory.
US Referenced Citations (5)