NbFeSb based half-heusler thermoelectric materials and methods of fabrication and use

Patent metadata

Field	Value
Publication number	US-10008653-B2
Application number	US-201514667056-A
Country	US
Kind code	B2
Filing date	Mar 24, 2015
Priority date	Mar 24, 2014
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

A thermoelectric half-Heusler material comprising niobium (Nb), iron (Fe) and antimony (Sb) wherein the material comprises grains having a mean grain size less than one micron. A method of making a nanocomposite half-Heusler thermoelectric material includes melting constituent elements of the thermoelectric material to form an alloy of the thermoelectric material, comminuting (e.g., ball milling) the alloy of the thermoelectric material into nanometer scale mean size particles, and consolidating the nanometer size particles to form the half-Heusler thermoelectric material comprising at least niobium (Nb), iron (Fe) and antimony (Sb) and having grains with a mean grain size less than one micron.

First claim

What is claimed is:

1. A thermoelectric half-Heusler material comprising:
niobium (Nb), iron (Fe), tin (Sn), and antimony (Sb), according to a formula Nb 1+δ−x A x Fe 1−y Co y Sb 1+δ−z Sn z
wherein the material comprises a mean grain size less than one micron subsequent to hot-pressing,
wherein the material comprises an electrical resistivity above 4.00×10 −6 ohm-mm and a thermal conductivity above 4.0 W/mK at above about 573 K.

2. The thermoelectric material of claim 1 , further comprising at least one of scandium (Sc) or yttrium (Y).

3. The thermoelectric material of claim 1 , wherein A comprises one or more of titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), or a rare earth element, and 0≤x<1.0, 0≤y<1.0, 0≤z <1.0, and −0.1≤δ≤0.1.

4. The thermoelectric material of claim 1 , wherein A comprises one or more of titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), or a rare earth element, and 0≤x<1.0, 0≤y<1.0, 0≤z <1.0, and δ=0.1.

5. The thermoelectric material of claim 1 , wherein the material comprises a p-type half-Heulser thermoelectric material with the formula Nb 1+δ−x Ti x Fe 1−y Co y Sb 1+δ−z Sn z and 0≤x≤0.5, 0≤y<1.0, 0≤z≤0.2 and −0.1≤δ≤0.1.

6. The thermoelectric material of claim 1 , wherein the material comprises a p-type half-Heusler thermoelectric material with the formula Nb 1+δ−x Ti x Fe 1−y Co y Sb 1+δ−z Sn z and 0.05≤x≤0.4, 0≤y<1.0, 0<z≤0.1 and −0.1≤δ≤0.1.

7. The thermoelectric material of claim 1 , wherein a dimensionless figure of merit, ZT, of the material is ≥0.8 for at least one temperature in the range 600-800° C.

8. The thermoelectric material of claim 1 , wherein the mean grain size of the thermoelectric material is less than 300 nm subsequent to hot-pressing.

9. The thermoelectric material of claim 1 , wherein at least 90% of the grains have a grain size less than 500 nm subsequent to hot-pressing.

10. The thermoelectric material of claim 1 , wherein the mean grain size is ≥10 nm.

11. The thermoelectric material of claim 1 , wherein at least a portion of the grains comprise at least one 10-50 nm size nanodot inclusion within the grain.

12. A method of making a nanocomposite half-Heusler thermoelectric material comprising:
melting, via arc melting or induction melting, a plurality of constituent elements comprising niobium (Nb), iron (Fe), and antimony (Sb) to form an ingot of an alloy of the half-Heusler thermoelectric material, wherein the alloy is according to a formula of Nb 1−x A x FeSb;
comminuting, via ball-milling, the alloy of the thermoelectric material into nanometer scale mean size particles; and
consolidating, via hot-pressing, the nanometer scale mean size particles to form, subsequent to hot-pressing, the half-Heusler thermoelectric material with a mean grain size less than one micron wherein the material comprises an electrical conductivity below 2.0×10 5 Sm −1 and a thermal conductivity below W/mK at above about 773 K.

13. The method of claim 12 , further comprising:
annealing the ingot of the alloy of the thermoelectric material at a temperature of 600-800° C. in a sub-atmospheric environment for 0.5-3 days prior to comminuting.

14. The method of claim 12 , wherein the nanometer scale mean size particles have a mean particle size in a range of 5-100 nm.

15. The method of claim 12 , wherein hot pressing the particles formed from the ingot comprises hot pressing at a peak temperature of 700-1100° C. and a pressure of 60-200 MPa.

16. The method of claim 12 , wherein the half-Heusler thermoelectric material further comprises tin (Sn).

17. The method of claim 12 , wherein A comprises at least one of titanium (Ti), zirconium (Zr), vanadium (V), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), cobalt (Co), or a rare earth element.

18. The method of claim 12 , wherein a dimensionless figure of merit, ZT, of the half-Heusler thermoelectric material is ≥0.8 for at least one temperature in the range 600-800° C.

19. The method of claim 12 , wherein consolidating the nanometer scale mean size particles comprises consolidating the particles to form the half-Heusler thermoelectric material having a mean grain size less than 300 nm.

20. The method of claim 19 , wherein consolidating the nanometer scale mean size particles comprises consolidating the particles to form the half-Heusler thermoelectric material wherein at least one of:
(i) at least 90% of the grains have a grain size less than 500 nm,
(ii) the mean grain size is ≥10 nm, and
(iii) at least a portion of the grains include a 10-50 nm size nanodot inclusion within the grain.

21. A thermoelectric half-Heusler material comprising:
niobium (Nb), iron (Fe) and antimony (Sb), wherein at least one of:
(i) a portion of the niobium in the half-Heusler material is substituted with titanium (Ti); and
(ii) a portion of the antimony in the half-Heusler material is substituted with tin (Sn), wherein the niobium, iron, antimony, titanium, and tin are ball-milled and hot-pressed to form the half-Heusler material comprising a mean grain size of less than 300 nm, an electrical resistivity above 4.00×10 −6 ohm-mm at above about 573 K, and a thermal conductivity above 4.0 W/mK at above about 573 K.

22. The thermoelectric half-Heusler material of claim 21 , wherein a portion of the iron in the half-Heusler material is substituted with cobalt (Co).

23. The thermoelectric half-Heusler material of claim 21 , wherein the material further comprises at least one of zirconium, (Zr), hafnium (Hf), vanadium (V), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), or a rare earth element.

24. The thermoelectric material of claim 21 , wherein up to 50 At % of the niobium in the half-Heusler material is substituted with titanium.

25. The thermoelectric material of claim 24 wherein 5-50 At % of the niobium in the half-Heusler material is substituted with titanium.

26. The thermoelectric material of claim 25 , wherein 25-40 At % of the niobium in the half-Heusler material is substituted with titanium.

27. The thermoelectric material of claim 21 , wherein up to 20 At % of the antimony in the half-Heusler material is substituted with tin.

28. The thermoelectric material of claim 27 , wherein the portion of antimony substituted with tin is greater than 0 At % and less than or equal to 10 At %.

29. A thermoelectric device comprising:
a first pair of thermoelectric legs, each of the first pair of legs comprising a first end, a second end, and a first n-type thermoelectric material; a second pair of thermoelectric legs, each of the second pair of legs comprising a first end, a second end, and a p-type thermoelectric material, wherein the first pair of thermoelectric legs are disposed parallel to the second pair of thermoelectric legs, and wherein the p-type thermoelectric material comprises a composition according to the formula Nb x Ti y FeSb, wherein x+y=1, a ZT above 0.8 above about 873 K, and a mean grain size less than 1 micron;
a first end of the device comprising a first electrical conductor and a second electrical conductor coupled to the first end of each of the first pair of thermoelectric legs and the first end of each of the second pair of thermoelectric legs; and
a second end of the device comprising

Assignees

• Univ Houston System
• Us Dept Energy

Inventors

• Joshi Giri
• Yang Jian
• Engber Michael
• Pantha Tej
• Cleary Martin
• Ren Zhifeng
• He Ran
• Kozinsky Boris

Classifications

• H01L35/34

  Electricity · mapped topic

• B22F2003/248

  Thermal after-treatment · CPC title

• H01L35/20

  Electricity · mapped topic

• B22F3/14

  simultaneously · CPC title

• C22C12/00

  Alloys based on antimony or bismuth · CPC title