# US 7,745,720 B2 · Thermoelectric material and thermoelectric device

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- Number: US 7,745,720 B2
- Document ID: US7745720B2
- Status: Granted
- Kind: B2
- Application number: 11/088,245
- Filed: 2005-03-24
- Published: 2005-10-06
- Granted: 2010-06-29
- Earliest claimed: 2004-03-30
- Assignees: Kabushiki Kaisha Toshiba; Toshiba Materials Co., Ltd.
- Inventors: Shinya Sakurada; Naoki Shutoh; Shinsuke Hirono
- Web page: https://patentgrep.com/patent/US7745720B2

## CPC

- H10N 10/854: comprising only metals (H10N10/852, H10N10/853 take precedence)
- C22C 19/058: {without Mo and W}
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

A thermoelectric material includes a composition represented by the following formula (A): (Tia1Zrb1Hfc1)xNiySn100-x-y (A) where 0<a1<1, 0<b1<1, 0<c1<1, a1+b1+c1=1, 30≦x≦35, and 30≦y≦35. The composition includes at least two MgAgAs crystal phases different in a lattice constant, and, assuming that X-ray diffraction peak intensity from a (422) diffraction plane of a first MgAgAs crystal phase having a smallest lattice constant and X-ray diffraction peak intensity from a (422) diffraction plane of a second MgAgAs crystal phase having a largest lattice constant be I1 and I2, respectively, a value of I1/(I1+I2) is in a range of 0.2 to 0.8.

## Claims

### Claim 1

A thermoelectric material comprising a composition represented by the following formula (A):
(Tia1Zrb1Hfc1)NiySn100-x-y (A)
wherein 0<a1<1, 0<b1<1, 0<c1<1, a1+b1+c1=1, 30≦x≦35, and 30≦y=35,
wherein the composition has at least two MgAgAs crystal phases different in a lattice constant, and,
assuming that X-ray diffraction peak intensity from (422) diffraction plane of a first MgAgAs crystal phase having a smallest lattice constant and X-ray diffraction peak intensity from a (422) diffraction plane of a second MgAgAs crystal phase having a largest lattice constant be I1 and I2, respectively, a value of I1/(I1+I2) being in a range of 0.2 to 0.8.

### Claim 2 (depends on 1)

The thermoelectric material according to claim 1, wherein the value of I1/(I1+I2) is in a range of 0.3 to 0.6.

### Claim 3 (depends on 1)

The thermoelectric material according to claim 1, wherein a part of Ti, Zr and Hf in the formula (A) is substituted by at least one element selected from the group consisting of V, Nb, Ta, Cr, Mo and W.

### Claim 4 (depends on 1)

The thermoelectric material according to claim 1, wherein a part of Ni in the formula (A) is substituted by at least one element selected from the group consisting of Mn, Fe, Co and Cu.

### Claim 5 (depends on 1)

The thermoelectric material according to claim 1, wherein a part of Sn in the formula (A) is substituted by at least one element selected from the group consisting of Si, Mg, As, Sb, Bi, Ge, Pb, Ga and In.

### Claim 6 (depends on 1)

The thermoelectric material according to claim 1, wherein the composition has been subjected to heat treatment under a temperature range of 1000° C. or more and less than 1200° C.

### Claim 7 (depends on 6)

The thermoelectric material according to claim 6, wherein the composition has been subjected to heat treatment under a temperature range of 1100° C. or more and less than 1180° C.

### Claim 8 (depends on 6)

The thermoelectric material according to claim 6, wherein the composition has been subjected to heat treatment in hot pressing.

### Claim 9

A thermoelectric material comprising a composition represented by the following formula (B):
(Lnd(Tia2Zrb2Hfc2)1-d)xNiySn100-x-y (B)
where Ln is at least one element selected from the group consisting of Y and rare earth elements, and 0<a2<1, 0<b2<1, 0<c2<1, a2+b2+c2=1, 30≦x≦35, and 30≦y≦35,
wherein the composition has at least two MgAgAs crystal phases different in a lattice constant, and,
assuming that X-ray diffraction peak intensity from a (422) diffraction plane of a first MgAgAs crystal phase having a smallest lattice constant and X-ray diffraction peak intensity from a (422) diffraction plane of a second MgAgAs crystal phase having a largest lattice constant be I1 and I2, respectively, a value of I1/(I1+I2) being in a range of 0.2 to 0.8.

### Claim 10 (depends on 9)

The thermoelectric material according to claim 9, wherein the value of I1/(I1+I2) is in a range of 0.3 to 0.6.

### Claim 11 (depends on 9)

The thermoelectric material according to claim 9, wherein a part of Ti, Zr and Hf in the formula (B) is substituted by at least one element selected from the group consisting of V, Nb, Ta, Cr, Mo and W.

### Claim 12 (depends on 9)

The thermoelectric material according to claim 9, wherein a part of Ni in the formula (B) is substituted by at least one element selected from the group consisting of Mn, Fe, Co and Cu.

### Claim 13 (depends on 9)

The thermoelectric material according to claim 9, wherein a part of Sn in the formula (B) is substituted by at least one element selected from the group consisting of Si, Mg, As, Sb, Bi, Ge, Pb, Ga and In.

### Claim 14 (depends on 9)

The thermoelectric material according to claim 9, wherein the composition has been subjected to heat treatment under a temperature range of 1000° C. or more and less than 1200° C.

### Claim 15 (depends on 14)

The thermoelectric material according to claim 14, wherein the composition has been subjected to heat treatment under a temperature range of 1100° C. or more and less than 1180° C.

### Claim 16 (depends on 14)

The thermoelectric material according to claim 14, wherein the composition has been subjected to heat treatment in hot pressing.

### Claim 17 (depends on 1)

A thermoelectric device comprising p-type thermoelectric chips and n-type thermoelectric chips connected alternately in series, and at least the p-type thermoelectric chips or the n-type thermoelectric chips comprising the thermoelectric material according to claim 1.

### Claim 18 (depends on 9)

A thermoelectric device comprising p-type thermoelectric chips and n-type thermoelectric chips connected alternately in series, and at least the p-type thermoelectric chips or the n-type thermoelectric chips comprising the thermoelectric material according to claim 9.

### Claim 19

A thermoelectric material comprising a composition represented by the following formula (A):
(Tia1Zrb1Hfc1)NiySn100-x-y (A)
wherein 0<a1<1, 0<b1<1, 0<c1<1, a1+b1+c1=1, 30≦x≦35, and 30≦y≦35,
wherein the composition has at least two MgAgAs crystal phases different in a lattice constant, and
wherein assuming that an X-ray diffraction peak intensity from a (422) diffraction plane of a first MgAgAs crystal phase having a smallest lattice constant and an X-ray diffraction peak intensity from a (422) diffraction plane of a second MgAgAs crystal phase having a largest lattice constant are I1 and I2, respectively, then the thermoelectric material has a value of I1/(I1+I2) in a range of 0.2 to 0.8 and a ZT value of higher than 1.3, wherein Z=α2/(ρκ) where α is a Seebeck coefficient of thermoelectric material, ρ is an electrical resistivity of the thermoelectric material, κ is a thermal conductivity of the thermoelectric material, and T is an absolute temperature.

### Claim 20

A thermoelectric material comprising a composition represented by the following formula (B):
(Lnd(Tia2Zrb2Hfc2)1-d)xNiySn100-x-y (B)
wherein Ln is at least one element selected from the group consisting of Y and rare earth elements, and 0<a2<1, 0<b2<1, 0<c2<1, a2+b2+c2=1, 30≦x≦35, and 30≦y≦35,
wherein the composition has at least two MgAgAs crystal phases different in a lattice constant, and
wherein assuming that an X-ray diffraction peak intensity from a (422) diffraction plane of a first MgAgAs crystal phase having a smallest lattice constant and an X-ray diffraction peak intensity from a (422) diffraction plane of a second MgAgAs crystal phase having a largest lattice constant are I1 and I2, respectively, then the thermoelectric material has a value of I1/(I1+I2) in a range of 0.2 to 0.8 and a ZT value of higher than 1.3, wherein Z=a2/(ρκ) where α is a Seebeck coefficient of thermoelectric material, ρ is an electrical resistivity of the thermoelectric material, κ is a thermal conductivity of the thermoelectric material, and T is an absolute temperature.