Nickel foam pin connections for inert anodes

• US 20040198103A1
• Filed: 04/02/2003
• Published: 10/07/2004
• Est. Priority Date: 04/02/2003
• Status: Active Grant

• Current Assignee: Alcoa Incorporated (Howmet Aerospace, Inc.)
• Original Assignee: Alcoa Incorporated (Howmet Aerospace, Inc.)
• Inventors: Latvaitis, J. Dean, Dunlap, Ronald M., Butcher, Kenneth
• Granted Patent: US 6,878,246 B2
• Time in Patent Office: Days
• US Class Current: 439/887
• CPC Class Codes: C25C 3/12 Anodes
• CPC Class Codes: C25C 7/025 used in cells for the electrolysis of melts
• CPC Class Codes: H01R 13/03 characterised by the material, e.g. plating, or coating materials

Abstract

An electrode assembly useful in manufacturing aluminum, contains a hollow inert electrode (12) containing a metal conductor (14) surrounded and held in place by at least one seal (16) and a mass of metal foam (26).

Claims

1. An electrode assembly comprising a hollow inert electrode, containing a metal conductor having a bottom surface substantially surrounded within the hollow inert electrode by a material comprising metal foam.

2. The electrode assembly of claim 1, wherein the inert electrode is a material selected from the group consisting of ceramic, cermet, metal, and mixtures thereof, and the conductor has a circular cross-section.

3. The electrode assembly of claim 1, wherein the foam has a reticulated, open cell network structure is sintered together, is compliant and has a conductivity of from about 1000 s/cm to about 26,000 s/cm.

4. The electrode assembly of claim 1, wherein the metal conductor is separated from the anode walls by the metal foam and the conductor can have a bottom of varying geometries and discontinuous diameters.

5. The electrode assembly of claim 1, wherein the metal foam is selected from the group of nickel foam, nickel alloy foam, and copper alloy foam.

6. An electrode assembly comprising an inert electrode having a hollow interior with a top portion and interior bottom and side walls;

a metal pin conductor having bottom and side surfaces, disposed within the electrode interior but not contacting the electrode interior walls; and

a seal surrounding the metal pin conductor at the top portion of the electrode, providing a gap around the metal pin conductor bottom surface between the metal pin conductor and the electrode interior bottom and side walls, where a metal foam having a density of from 5% to 40% of the solid parent metal fills the bottom portion of the gap.

7. The electrode assembly of claim 6, wherein the conductor has a circular cross-section and can have a bottom of varying geometries and discontinuous diameters.

8. The electrode assembly of claim 6, wherein the foam has a reticulated, open cell network structure is sintered together, is compliant and has a conductivity of from about 1000 s/cm to about 26,000 s/cm.

9. The electrode assembly of claim 6, wherein the metal pin conductor is selected from at least one of nickel and corrosion protected alloy steel and has a circular cross-section, and the inert electrode is a material selected from the group consisting of ceramic and cermet.

10. The electrode assembly of claim 6, wherein the metal foam has a melting temperature over 1000°

C. and is compliant, providing a buffer between the metal pin conductor and the electrode interior bottom and side walls.

11. The electrode assembly of claim 6, wherein the metal foam is selected from the group consisting of nickel foam, nickel alloy foam and copper alloy foam.

12. A method of producing an electrode assembly comprising:

(1) providing an inert electrode having a hollow interior with a top portion and interior bottom and side walls;

(2) inserting a metal pin conductor having bottom and side surfaces and a metal foam into the hollow interior of the electrode; and

(3) sealing the top portion of the electrode.

13. The method of claim 12 where the metal foam has a reticulated, open cell network structure of metal particles, is sintered together and is compliant, with a melting temperature over 1000°

C.

14. The method of claim 12, wherein the inert electrode is a green inert anode material selected from the group consisting of ceramic and cermet and the pin conductor, and metal foam are inserted into the hollow interior of the anode and then the assembly is heated after step (3) causing the cermet to shrink, compress the metal foam and secure the pin conductor.

15. The method of claim 14, wherein the inert electrode is a green inert anode material selected from the group consisting of ceramic, cermet, metal, and mixtures thereof, and the metal foam is inserted into the hollow interior of the anode and the anode and nickel foam are heated after step (3) causing the cermet to shrink and compress the metal foam, and then, after cooling the pin conductor is inserted into the metal foam by threading or welding.

16. The method of claim 14, wherein the inert electrode is a sintered inert anode material selected from the group consisting of ceramic and cermet and the pin conductor, and metal foam are inserted into the hollow interior of the anode under a further interference fit causing radial and longitudinal compression of the metal foam, densifying the foam.

17. The method of claim 14, wherein the metal foam is selected from the group consisting of nickel foam and nickel alloy foam and has a density of from 5% to 40% of the solid parent metal.