Thermoelectric material and thermoelectric module using the thermoelectric material
Disclosed is a thermoelectric material comprising a main phase which is represented by the following composition formula and having an MgAgAs-type crystalline structure: (T a1 Zr b1 Hf c1 ) x Co y Sb 100-x-y wherein 0<a1<1, 0<b1<1, 0<c1<1, a1+b1+c1=1, 30≦x ≦35, and 30≦y≦35.
1. A thermoelectric material comprising a main phase which is a sintered body and represented by the following composition formula and having an MgAgAs-type crystalline structure:
(Ti a1 Zr b1 Hf c1 ) x Co y Sb 100-x-y
wherein 0<a1<1,0<b1<1,0<c1<1,a1+b1+c1=1,30≦×≦35, and 30≦y≦35, and 0.3-30 atom. % of Sb is replaced by at least one selected from the group consisting of Se, Te, Ge and Sn.
2. The thermoelectric material according to claim 1 , wherein the sintered body has a dimensionless figure of merit ZT value of 0.20 to 0.33 at 300K when 0.3-30 atom. % of Sb is replaced by at least one selected from the group consisting of Ge and Sn.
3. The thermoelectric material according to claim 1 , wherein Sb is replaced by Sn.
4. The thermoelectric material according to claim 1 , wherein a1 in the composition formula is confined within the range of 0.2<a1<0.8.
5. The thermoelectric material according to claim 1 , wherein b1 in the composition formula is confined within the range of 0.2<b1<0.8.
6. The thermoelectric material according to claim 1 , wherein c1 in the composition formula is confined within the range of 0.2<c1<0.8.
7. The thermoelectric material according to claim 1 , wherein x in the composition formula is confined within the range of 33≦x≦34.
8. The thermoelectric material according to claim 1 , wherein y in the composition formula is confined within the range of 33≦y≦34.
9. The thermoelectric material according to claim 1 , wherein Ti, Zr and Hf in the composition formula are partially replaced by at least one selected from the group consisting of V, Nb, Ta, Cr, Mo, W, Sc, Y, Th, U and lanthanoids.
10. The thermoelectric material according to claim 9 , wherein Ti, Zr and Hf are partially replaced at a ratio of not more than 30 atom. % of the total quantity of Ti, Zr and Hf.
11. The thermoelectric material according to claim 1 , wherein Co in the composition formula is partially replaced by at least one selected from the group consisting of Ni, Pd, Pt, Fe, Ru and Os.
12. The thermoelectric material according to claim 11 , wherein Co is partially replaced at a ratio of not more than 30 atom. % of Co.
13. A thermoelectric module comprising p-type elements comprising a p-type thermoelectric material and n-type elements comprising an n-type thermoelectric material, these p-type and n-type elements being alternately connected with each other in series, and the p-type thermoelectric material comprising the thermoelectric material according to claim 1 .
14. The thermoelectric module according to claim 13 , wherein the sintered body has a dimensionless figure of merit ZT value of 0.20 to 0.33 at 300K when 0.3-30 atom. % of Sb is replaced by at least one selected from the group consisting of Ge and Sn.
15. The thermoelectric material according to claim 13 , wherein Sb is replaced by Sn.
16. The thermoelectric module according to claim 13 , wherein at least one of a1, b1 and c1 in the composition formula are confined to more than 0.2 and less than 0.8.
17. The thermoelectric module according to claim 13 , wherein at least one of x and y in the composition formula are confined to 33 or more and 34 or less.
18. The thermoelectric module according to claim 13 , wherein said thermoelectric module is a thermal battery.
19. The thermoelectric module according to claim 13 , wherein said thermoelectric module is a cooler.