Method for producing La/Ce/MM/Y base alloys, resulting alloys and battery electrodes

Patent metadata

Field	Value
Publication number	US-9525176-B2
Application number	US-201313694846-A
Country	US
Kind code	B2
Filing date	Jan 10, 2013
Priority date	Jul 20, 2010
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

Abstract

A carbothermic reduction method is provided for reducing a La-, Ce-, MM-, and/or Y-containing oxide in the presence of carbon and a source of a reactant element comprising Si, Ge, Sn, Pb, As, Sb, Bi, and/or P to form an intermediate alloy material including a majority of La, Ce, MM, and/or Y and a minor amount of the reactant element. The intermediate material is useful as a master alloy for in making negative electrode materials for a metal hydride battery, as hydrogen storage alloys, as master alloy additive for addition to a melt of commercial Mg and Al alloys, steels, cast irons, and superalloys; or in reducing Sm 2 O 3 to Sm metal for use in Sm—Co permanent magnets.

First claim

The invention claimed is:

1. A method of making a rare earth-based alloy, comprising carbothermically reducing an oxide selected from the group consisting of La-containing oxide, a Ce-containing oxide, and MM-containing oxide in the presence of carbon as a reducing agent and a source of a reactant element X at a temperature less than about 1800 degrees C. wherein X is selected from the group consisting of Si, Ge, Sn, Pb, As, Sb, Bi, and P to achieve substantial completion of the carbothermic reduction reaction to form a low carbon alloy that comprises a majority of a rare earth element selected from the group consisting of La, Ce, and MM, a minor amount of X present in an amount of about 1 weight % to 18 weight % of the alloy, and a low carbon content in an amount of about 2 weight % or less of the alloy.

2. The method of claim 1 wherein the oxide comprises La 2 O 3 .

3. The method of claim 2 wherein the alloy comprises LaSi 0.5 .

4. The method of claim 2 wherein the alloy comprises LaX′ 0.5 , where X′ is selected from the group consisting of Ge, Sn, Pb, As, Sb, Bi, and P.

5. The method of claim 1 wherein the carbothermic reduction is initiated at a temperature of at least about 1300 degrees C.

6. The method of claim 1 wherein the oxide comprises CeO 2 .

7. The method of claim 6 wherein the alloy comprises CeSi 0.5 .

8. The method of claim 6 wherein the alloy comprises CeX′ 0.5 , where X′ is selected from the group consisting of Ge, Sn, Pb, As, Sb, Bi, and P.

9. The method of claim 1 wherein the oxide comprises mischmetal (MM) oxide.

10. The method of claim 9 wherein the alloy comprises MMSi 0.5 .

11. The method of claim 9 wherein the alloy comprises MMX′ 0.5 , where X is selected from the group consisting of Ge, Sn, Pb, As, Sb, Bi, and P.

12. The method of claim 1 wherein zirconium oxide also is present and reduced.

13. The method of claim 1 wherein the reactant element is Si.

14. The method of claim 1 including providing a substantially stoichiometric amount of carbon as a reducing agent relative to oxides present.

15. The method of claim 1 wherein the carbon content of the alloy is in a range of about 0.005 weight % to about 2 weight % C.

16. A method of making a rare earth-based alloy, comprising carbothermically reducing an oxide selected from the group consisting of a La-containing oxide, a Ce-containing oxide, and a MM-containing oxide in the presence of carbon particles as a reducing agent and silicon particles to achieve substantial completion of the carbothermic reduction reaction at a temperature below 1800 degrees C. to form a low carbon alloy that comprises a majority of a rare earth element selected from the group consisting of La, Ce, and MM, a minor amount of Si present in a range of about 1.0 weight % to about 18 weight % of the alloy, and an amount of C in a range of about 0.005 weight % to about 2 weight % of the alloy.

Assignees

• Gschneidner Jr Karl A
• Schmidt Frederick A
• Univ Iowa State Res Found Inc

Inventors

• Gschneidner Jr Karl A
• Schmidt Frederick A

Classifications

• C22C28/00

  Alloys based on a metal not provided for in groups C22C5/00 - C22C27/00 · CPC title

• H01M4/242

  Hydrogen storage electrodes · CPC title

• H01M10/30

  Nickel accumulators (H01M10/34 takes precedence) · CPC title

• C22C1/06 Primary

  with the use of special agents for refining or deoxidising · CPC title

• H01M10/345

  Gastight metal hydride accumulators · CPC title