JP2000261048A - Semiconductor material for thermoelectric conversion and manufacture of the same - Google Patents
Semiconductor material for thermoelectric conversion and manufacture of the sameInfo
- Publication number
- JP2000261048A JP2000261048A JP11058845A JP5884599A JP2000261048A JP 2000261048 A JP2000261048 A JP 2000261048A JP 11058845 A JP11058845 A JP 11058845A JP 5884599 A JP5884599 A JP 5884599A JP 2000261048 A JP2000261048 A JP 2000261048A
- Authority
- JP
- Japan
- Prior art keywords
- thermoelectric conversion
- alloy powder
- semiconductor material
- metal
- powder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000000463 material Substances 0.000 title claims abstract description 62
- 238000006243 chemical reaction Methods 0.000 title claims abstract description 52
- 239000004065 semiconductor Substances 0.000 title claims abstract description 41
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 12
- 239000000843 powder Substances 0.000 claims abstract description 74
- 239000000956 alloy Substances 0.000 claims abstract description 44
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 44
- 238000002844 melting Methods 0.000 claims abstract description 11
- 230000008018 melting Effects 0.000 claims abstract description 11
- 238000000034 method Methods 0.000 claims abstract description 10
- 239000000203 mixture Substances 0.000 claims abstract description 10
- 239000000126 substance Substances 0.000 claims abstract description 8
- 230000001590 oxidative effect Effects 0.000 claims abstract description 7
- 239000002184 metal Substances 0.000 claims description 51
- 229910052751 metal Inorganic materials 0.000 claims description 51
- 239000002270 dispersing agent Substances 0.000 claims description 12
- 238000010304 firing Methods 0.000 claims description 12
- 239000002994 raw material Substances 0.000 claims description 7
- 239000002245 particle Substances 0.000 claims description 6
- 229910018125 Al-Si Inorganic materials 0.000 claims description 2
- 229910018520 Al—Si Inorganic materials 0.000 claims description 2
- 229910020968 MoSi2 Inorganic materials 0.000 claims description 2
- 229910018487 Ni—Cr Inorganic materials 0.000 claims description 2
- 229910008814 WSi2 Inorganic materials 0.000 claims description 2
- 229910052804 chromium Inorganic materials 0.000 claims description 2
- 229910052802 copper Inorganic materials 0.000 claims description 2
- 229910052750 molybdenum Inorganic materials 0.000 claims description 2
- 229910052697 platinum Inorganic materials 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- 229910052721 tungsten Inorganic materials 0.000 claims description 2
- 229910052720 vanadium Inorganic materials 0.000 claims description 2
- 229910052726 zirconium Inorganic materials 0.000 claims 1
- 229910018985 CoSb3 Inorganic materials 0.000 abstract description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 abstract description 6
- 238000002156 mixing Methods 0.000 abstract description 6
- 230000008569 process Effects 0.000 abstract description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 abstract description 3
- 239000002019 doping agent Substances 0.000 abstract description 3
- 229910052757 nitrogen Inorganic materials 0.000 abstract description 3
- 239000001257 hydrogen Substances 0.000 abstract description 2
- 229910052739 hydrogen Inorganic materials 0.000 abstract description 2
- 230000003247 decreasing effect Effects 0.000 abstract 1
- 230000007423 decrease Effects 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 7
- 230000000694 effects Effects 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 239000006185 dispersion Substances 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 229910002909 Bi-Te Inorganic materials 0.000 description 2
- -1 TSb3 (T: Co Chemical class 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 229910052741 iridium Inorganic materials 0.000 description 2
- 229910052707 ruthenium Inorganic materials 0.000 description 2
- 150000003498 tellurium compounds Chemical class 0.000 description 2
- 229910002899 Bi2Te3 Inorganic materials 0.000 description 1
- 229910018989 CoSb Inorganic materials 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- 229940058905 antimony compound for treatment of leishmaniasis and trypanosomiasis Drugs 0.000 description 1
- 150000001463 antimony compounds Chemical class 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 229910052714 tellurium Inorganic materials 0.000 description 1
- PORWMNRCUJJQNO-UHFFFAOYSA-N tellurium atom Chemical compound [Te] PORWMNRCUJJQNO-UHFFFAOYSA-N 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
Landscapes
- Powder Metallurgy (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、熱電変換モジュー
ルにおいてＰ型またはＮ型の熱電変換用半導体素子とし
て使用される熱電変換用半導体材料およびその製造方法
に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoelectric conversion semiconductor material used as a P-type or N-type thermoelectric conversion semiconductor element in a thermoelectric conversion module and a method for producing the same.
【０００２】[0002]
【従来の技術】従来、高性能の熱電変換材料としては、
Bi2Te3, Bi2Sb8Te15, BiTe2Se などのテルル系化合物が
知られている。また、TSb3(T:Co, Ir, Ru)などのアンチ
モン系化合物の内、例えばCoSb3 も熱電変換材料として
知られている。このCoSb3 熱電変換材料は、約600 ℃ま
での温度範囲において使用可能な熱電変換材料として知
られている。2. Description of the Related Art Conventionally, as high performance thermoelectric conversion materials,
Tellurium compounds such as Bi2Te3, Bi2Sb8Te15 and BiTe2Se are known. Among antimony compounds such as TSb3 (T: Co, Ir, Ru), for example, CoSb3 is also known as a thermoelectric conversion material. This CoSb3 thermoelectric material is known as a thermoelectric material usable in a temperature range up to about 600 ° C.
【０００３】[0003]
【発明が解決しようとする課題】Bi-Te 系に代表される
テルル系化合物より成る熱電変換材料は、室温では比較
的高い性能指数Ｚ(Z=3×10-3[1/K])を有しているが、30
0 ℃以上の高温では、特性が劣化するという問題点があ
った。ここで、性能指数Ｚは、αをゼーベック係数、σ
を電気伝導率、κを熱伝導率とするとき、Ｚ＝α2 σ／
κで表されるものである。また、テルル系化合物より成
る熱電変換材料は、融点が低く化学的安定性に欠けると
もに組成変動による特性のばらつきが生じ易いなどの問
題点もあった。A thermoelectric conversion material composed of a tellurium compound represented by a Bi-Te compound has a relatively high figure of merit Z (Z = 3 × 10 −3 [1 / K]) at room temperature. Have, but 30
At a high temperature of 0 ° C. or higher, there is a problem that characteristics are deteriorated. Here, the figure of merit Z is such that α is a Seebeck coefficient, σ
Is electrical conductivity and κ is thermal conductivity, Z = α 2 σ /
It is represented by κ. Further, the thermoelectric conversion material made of a tellurium-based compound has a problem that it has a low melting point, lacks chemical stability, and tends to cause variations in characteristics due to composition fluctuation.
【０００４】また、TSb3(T:Co, Ir, Ru)などのSb系化合
物より成る熱電変換材料の内、特にCoSb3 は使用可能な
温度範囲がBi-Te 系化合物に比較して大幅に広いという
利点がある。このような CoSb3を主成分とする熱電変換
用半導体材料の性能指数を改善する方法の一つとして、
熱伝導率κを減少させるために、微細な粉末を混入させ
ることが提案されている。Further, among thermoelectric conversion materials made of Sb-based compounds such as TSb3 (T: Co, Ir, Ru), CoSb3 has a usable temperature range that is much wider than that of Bi-Te-based compounds. There are advantages. One of the methods to improve the figure of merit of the thermoelectric conversion semiconductor material containing CoSb3 as a main component is as follows.
It has been proposed to mix fine powder to reduce the thermal conductivity κ.
【０００５】このような熱伝導率を減少させるための粉
末としては、例えばB.A.Cook and J.L.Harringa, Proc.
13th. ICT, 12 (1994) に記載されているように、Ｂ粉
末やＢＮ粉末が提案されているいるが、熱伝導率を低下
させるという目的のためには粒径がオングストロームレ
ベル、大きくても１００程度のものとする必要があると
考えられていた。しかしながら、このように微細な粉末
は、高価である、取扱がきわめて面倒である、生産性が
悪いなどの問題があった。[0005] Powders for reducing such thermal conductivity include, for example, BACook and JL Harringa, Proc.
As described in 13th. ICT, 12 (1994), B powder and BN powder have been proposed, but for the purpose of lowering the thermal conductivity, even if the particle size is as large as angstrom, It was thought that it was necessary to make it about 100. However, such fine powder has problems such as being expensive, extremely troublesome to handle, and low in productivity.
【０００６】本発明の目的は、CoSb3 を主成分とする熱
電変換用半導体材料の上述した問題点を解決し、電気伝
導率の低下を抑えながら熱伝導率を低下させることがで
き、したがって性能指数を効率良く向上することができ
る熱電変換用半導体材料を提供しようとするものであ
る。An object of the present invention is to solve the above-mentioned problems of the thermoelectric conversion semiconductor material containing CoSb3 as a main component, and to reduce the thermal conductivity while suppressing the decrease in the electrical conductivity. It is an object of the present invention to provide a thermoelectric conversion semiconductor material capable of efficiently improving the temperature.
【０００７】本発明は、さらに安価で、取扱が容易で、
生産性の高い分散材を用いて高い性能を有する熱電変換
用半導体材料を、汎用的な焼成プロセスを用いて容易か
つ効率良く製造することができる方法を提供しようとす
るものである。The present invention is more inexpensive, easier to handle,
An object of the present invention is to provide a method capable of easily and efficiently producing a thermoelectric conversion semiconductor material having high performance using a highly productive dispersant by using a general-purpose baking process.
【０００８】[0008]
【課題を解決するための手段】本発明は、熱電変換モジ
ュールに使用されるＰ型またはＮ型の熱電変換用半導体
材料において、化学組成がCoSbx (2.7＜x ＜3.4)で表さ
れる主成分に、分散材として、焼成温度よりも融点の高
い金属または合金粉末を分散させたことを特徴とするも
のである。According to the present invention, there is provided a P-type or N-type semiconductor material for thermoelectric conversion used in a thermoelectric conversion module, the main component of which has a chemical composition represented by CoSbx (2.7 <x <3.4). In addition, a metal or alloy powder having a melting point higher than the firing temperature is dispersed as a dispersing material.
【０００９】このような本発明による熱電変換用半導体
材料においては、前記分散材である金属または合金粉末
を、主成分に対して0.01wt% 〜20wt% の割合で混入させ
るのが好適である。また、金属粉末としては、Mn, V, Z
r, Ti, W, Mo, Cr, Cu, Ptより成る群から選択された金
属粉末とするのが好適であり、合金粉末としては、WC,
Ni-Cr, Al-Si, MoSi2, WSi2 より成る群から選択された
合金粉末とするのが好適であるが、焼成温度よりも融点
の高い金属または合金粉末に相当するものであれば、こ
れに限るものではない。In the semiconductor material for thermoelectric conversion according to the present invention, it is preferable that the metal or alloy powder as the dispersant is mixed at a ratio of 0.01 wt% to 20 wt% with respect to the main component. In addition, Mn, V, Z
It is preferable to use a metal powder selected from the group consisting of r, Ti, W, Mo, Cr, Cu, and Pt, and as the alloy powder, WC,
It is preferable to use an alloy powder selected from the group consisting of Ni-Cr, Al-Si, MoSi2, and WSi2, but if it corresponds to a metal or alloy powder having a melting point higher than the sintering temperature, it may be used. It is not limited.
【００１０】一般に熱伝導率を減少させるには、オング
ストロームレベルのセラミックス微粉末を混入させる方
が良いと考えられており、従来は熱伝導率の高い金属ま
たは合金粉末を混入することによって熱伝導率を減少さ
せるということは提案されていない。本発明において、
熱伝導率の高い金属または合金粉末を混入することによ
っても熱伝導率を低下させることができるのは、金属粉
末とマトリックスとの境界に熱的な障壁が形成されるた
めであると考えられる。また、金属粉末の粒径について
は特に限定はないが、価格、取扱易さ、生産性などを考
慮して、サブミクロンから数百ミクロンとするのが好適
である。In general, it is considered that it is better to mix Angstrom level ceramic fine powder in order to reduce the thermal conductivity. Conventionally, by mixing a metal or alloy powder having high thermal conductivity, the thermal conductivity is reduced. It has not been proposed to reduce In the present invention,
The reason why the thermal conductivity can be reduced by mixing a metal or alloy powder having a high thermal conductivity is considered to be because a thermal barrier is formed at the boundary between the metal powder and the matrix. The particle size of the metal powder is not particularly limited, but is preferably from submicron to several hundred microns in consideration of price, ease of handling, productivity, and the like.
【００１１】このような本発明による熱電変換用半導体
材料によれば、熱伝導率を減少させることができるの
で、性能指数を効率よく向上することができる。また、
金属または合金粉末の融点は焼成温度よりも高いので化
学的に安定であり、良好な性能指数をどのような条件下
でも長期間に亘って保つことができる。According to the semiconductor material for thermoelectric conversion according to the present invention, since the thermal conductivity can be reduced, the figure of merit can be efficiently improved. Also,
Since the melting point of the metal or alloy powder is higher than the firing temperature, it is chemically stable, and a good figure of merit can be maintained over a long period under any conditions.
【００１２】さらに、本発明による熱電変換用半導体材
料の製造方法は、熱電変換モジュールに使用されるＰ型
またはＮ型の熱電変換用半導体材料を製造するに当た
り、主成分の化学組成がCoSbx (2.7＜x ＜3.4)で表され
る原料粉末と、金属または合金粉末とを混合し、所定の
形状の成形した後、還元性雰囲気または非酸化性雰囲気
中において、前記金属または合金粉末の融点よりも低い
温度で焼成することを特徴とするものである。ここで、
非酸化性雰囲気とは、窒素やアルゴンのような不活性雰
囲気や超高真空雰囲気のみならず、水素ガスのような還
元性雰囲気をも含むものである。Further, according to the method of manufacturing a semiconductor material for thermoelectric conversion according to the present invention, when manufacturing a P-type or N-type semiconductor material for thermoelectric conversion used in a thermoelectric conversion module, the chemical composition of the main component is CoSbx (2.7 <X> The raw material powder represented by <3.4) and a metal or alloy powder are mixed and molded into a predetermined shape, and then in a reducing atmosphere or a non-oxidizing atmosphere, the melting point of the metal or alloy powder is reduced. It is characterized by firing at a low temperature. here,
The non-oxidizing atmosphere includes not only an inert atmosphere such as nitrogen or argon or an ultra-high vacuum atmosphere but also a reducing atmosphere such as hydrogen gas.
【００１３】このような本発明による熱電変換用半導体
材料の製造方法によれば、粒径がサブミクロンから数百
ミクロンと従来のセラミックス粉末よりも大きく、した
がって安価で、取扱が容易で、生産性の良い金属または
合金粉末を分散材として使用することができるので、汎
用的な焼成プロセスで容易かつ効率良く作製することが
できる。また、この金属または合金粉末の融点は焼成温
度よりも高いので、焼成中に金属または合金粉末が溶融
してしまうことがなく、熱伝導率を低下させる機能が十
分に発揮させることができる。According to the method for producing a semiconductor material for thermoelectric conversion according to the present invention, the particle size is from submicron to several hundred microns, which is larger than that of the conventional ceramic powder. Since a good metal or alloy powder can be used as a dispersant, it can be easily and efficiently produced by a general-purpose firing process. Further, since the melting point of the metal or alloy powder is higher than the firing temperature, the metal or alloy powder does not melt during firing, and the function of lowering the thermal conductivity can be sufficiently exhibited.
【００１４】上述したように、本発明による熱電変換用
半導体材料においては、CoSbx (2.7＜x ＜3.4)で表され
る母材に金属または合金粉末より成る分散材を分散させ
ることによって熱伝導率は低下し、性能は向上する。さ
らに、効率良く性能を向上させるためには、主成分に対
する金属または合金粉末より成る分散材の添加量を0.01
wt% 〜20wt% とするのが好ましい。その理由は、金属粉
末を0.01wt% 未満とすると、熱伝導率の顕著な改善効果
が見られず、また20wt% よりも多量に混入させると、ゼ
ーベック係数の低下が大きくなり、分散材を入れたこと
による性能指数改善効果が小さくなるためである。As described above, in the semiconductor material for thermoelectric conversion according to the present invention, the thermal conductivity is obtained by dispersing a dispersing material made of metal or alloy powder in a base material represented by CoSbx (2.7 <x <3.4). Decrease and performance improves. Furthermore, in order to improve the performance efficiently, the amount of the dispersing agent composed of metal or alloy powder to the main component should be 0.01
It is preferable that the content be from wt% to 20 wt%. The reason is that if the metal powder is less than 0.01 wt%, no remarkable improvement effect of the thermal conductivity is seen, and if it is mixed in more than 20 wt%, the decrease of Seebeck coefficient becomes large, This is because the effect of improving the figure of merit due to this is reduced.
【００１５】本発明による熱電変換用半導体材料の製造
方法においては、酸素含有量を制限するために、焼成前
の原料粉末の含有酸素量を低くして非酸化性雰囲気中で
焼成を行うか、焼成を還元性雰囲気中で行なうことによ
って酸素を除くようにすることができる。このような方
法によれば、導電型を決めるドーパントとして作用する
金属が酸化されることがなく、したがってドーピングの
制御性が高くなり、所望の特性を有する熱電変換用半導
体材料が得られることを確かめた。In the method of manufacturing a semiconductor material for thermoelectric conversion according to the present invention, in order to limit the oxygen content, the firing is performed in a non-oxidizing atmosphere by reducing the oxygen content of the raw material powder before firing. Oxygen can be removed by performing calcination in a reducing atmosphere. According to such a method, it is confirmed that a metal acting as a dopant that determines the conductivity type is not oxidized, so that the controllability of doping is increased, and a semiconductor material for thermoelectric conversion having desired characteristics can be obtained. Was.
【００１６】[0016]
【発明の実施の形態】以下本発明による金属または合金
粉末を分散させたCoSbx (2.7＜x ＜3.4)系熱電変換材料
の幾つかの実施例を比較例とともに示すが、これらの実
施例および比較例とも以下のプロセスによって製作し
た。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, several examples of CoSbx (2.7 <x <3.4) thermoelectric conversion materials in which a metal or alloy powder according to the present invention is dispersed will be shown together with comparative examples. Both examples were manufactured by the following process.
【００１７】粒状のCo, Sbを出発原料として用い、所定
量を秤量した後、圧粉して非酸化性雰囲気中で20〜96時
間の熱処理を行った。これを乳鉢にて粗粉砕した後、遊
星回転ボールミルを用いて乾式粉砕を行い、平均粒径が
100 μm 以下となるまで微粉砕した。これらの工程中に
金属または合金粉末を分散材として混入させた。この金
属または合金粉末の粒径は、0.1 μｍ〜120 μｍとし
た。After using Co and Sb in a granular form as starting materials, a predetermined amount was weighed, and then compacted and heat-treated in a non-oxidizing atmosphere for 20 to 96 hours. After coarsely pulverized in a mortar, dry pulverized using a planetary rotary ball mill, the average particle size is
It was pulverized to 100 μm or less. During these steps, metal or alloy powder was mixed in as a dispersant. The particle size of the metal or alloy powder was 0.1 μm to 120 μm.
【００１８】このようにして作製した合金粉末を、成形
圧７Ton/cm2 で成形した後、600 〜750 ℃の範囲で非酸
化性雰囲気である窒素雰囲気中または還元性雰囲気であ
る水素中で３〜６時間の熱処理を施し、焼結体を得た。After the alloy powder thus produced is compacted at a compaction pressure of 7 Ton / cm 2, it is heated in a non-oxidizing atmosphere of nitrogen or a reducing atmosphere of hydrogen at 600 to 750 ° C. Heat treatment was performed for up to 6 hours to obtain a sintered body.
【００１９】ここで、焼成前の原料粉末としては、上述
したように単体元素からなる原料粉末を所定量秤量した
後に混合するものだけに限られるものではなく、例えば
単体の原料を溶融、粉砕したものや、あるいは元素含有
比が目的の比率となるように、溶融、粉砕した粉末と単
体元素粉末とを混合したものなどを用いることもでき
る。The raw material powder before firing is not limited to the raw material powder composed of a single element as described above, which is mixed after a predetermined amount of the raw material powder is weighed. For example, a single raw material is melted and pulverized. It is also possible to use, for example, a mixture of a powder obtained by melting and pulverization and a powder of a single element so that the element content ratio becomes a target ratio.
【００２０】また、実際の製造工程では最終的に得られ
る熱電変換用半導体材料の導電型を決定するためのドー
パントとしてGe, Sn, Feなどの金属を微小量添加する
が、このことは本発明の要旨ではないので詳細な説明は
省略する。In the actual manufacturing process, a very small amount of a metal such as Ge, Sn, Fe or the like is added as a dopant for determining the conductivity type of the semiconductor material for thermoelectric conversion finally obtained. Therefore, detailed description is omitted.
【００２１】表１は上述したプロセスによって作製した
焼結体の組成比と、特性を示すものであり、添加した金
属または合金粉末の種類、CoSbx (2.7＜x ＜3.4)で表さ
れる主成分に対する調合比を重量％で示すとともに室温
におけるゼーベック係数および熱伝導率κの測定結果も
示している。この表１には、本発明の条件から外れるも
のもあり、これは比較例として示した。すなわち、試料
１〜２８までは本発明による実施例であり、試料２９は
分散材を分散させていない比較例である。Table 1 shows the composition ratio and characteristics of the sintered body produced by the above-described process. The type of the added metal or alloy powder and the main component represented by CoSbx (2.7 <x <3.4) And the results of measurement of the Seebeck coefficient and the thermal conductivity κ at room temperature are also shown. In Table 1, some of the conditions deviate from the conditions of the present invention, which are shown as comparative examples. That is, samples 1 to 28 are examples according to the present invention, and sample 29 is a comparative example in which the dispersant is not dispersed.
【００２２】[0022]
【表１】 [Table 1]
【００２３】また、試料１〜１６は第１グループの実施
例であり、試料１７〜２８は第２グループの実施例であ
る。第１グループの実施例では、分散材の調合比を0.01
wt%〜20wt% としたものであり、この場合には、熱伝導
率が比較例の３０〜６０％と大きく低下している。ま
た、第２グループの実施例においても、熱伝導率は比較
例のものよりも小さくなっている。したがって、熱電変
換用半導体材料として要求される条件を満足するように
分散材の種類および調合比を選択すれば良い。Samples 1 to 16 are examples of the first group, and samples 17 to 28 are examples of the second group. In the embodiment of the first group, the mixing ratio of the dispersant is 0.01
wt% to 20 wt%, and in this case, the thermal conductivity is significantly reduced to 30 to 60% of the comparative example. Further, also in the examples of the second group, the thermal conductivity is smaller than that of the comparative example. Therefore, the kind and the mixing ratio of the dispersant may be selected so as to satisfy the conditions required as the semiconductor material for thermoelectric conversion.
【００２４】表１から分かるように、金属または合金粉
末を添加量と、熱伝導率の減少程度とを対比して考える
と、金属または合金粉末の添加量が0.01wt% よりも少な
いと熱伝導率は大きくは減少せず、性能向上の効果が小
さく、20wt% よりも多くするとゼーベック係数が大きく
低下してしまい熱伝導率の低下によって得られる性能向
上の効果が小さくなってしまうことがわかる。したがっ
て、本発明においては金属または合金粉末の添加量を0.
01wt% 〜20wt% とするのが好適である。As can be seen from Table 1, when the amount of the metal or alloy powder added and the degree of decrease in the thermal conductivity are considered in contrast, if the amount of the metal or alloy powder added is less than 0.01 wt%, the thermal conductivity is reduced. It can be seen that the rate does not decrease significantly, and the effect of improving the performance is small. If it exceeds 20 wt%, the Seebeck coefficient is greatly reduced, and the effect of improving the performance obtained by lowering the thermal conductivity is reduced. Therefore, in the present invention, the addition amount of the metal or alloy powder is 0.
It is preferable that the content be 01 wt% to 20 wt%.
【００２５】図１は、金属または合金粉末を分散させた
本発明の幾つかの実施例の熱伝導率と、金属または合金
粉末を分散させていない比較例の熱伝導率とを対比して
示すものである。種類によって多少の差はあるが、いず
れの金属または合金粉末を用いても熱伝導率が減少して
いることが分かる。FIG. 1 shows the thermal conductivity of some embodiments of the present invention in which the metal or alloy powder is dispersed, and the thermal conductivity of the comparative example in which the metal or alloy powder is not dispersed. Things. Although there is a slight difference depending on the type, it can be seen that the thermal conductivity is reduced by using any metal or alloy powder.
【００２６】図２のグラフは、CoSbx (2.7＜x ＜3.4)に
対する金属粉末の添加量と、熱伝導率との関係を室温に
て測定した結果を示すものである。このグラフから明ら
かなように、金属粉末の添加量を減らすことにより熱伝
導率の減少効果は小さくなり、主成分に対する添加量が
0.01wt% 未満の試料では金属粉末の添加による熱伝導率
の低下が顕著には現れていないが、比較例に比べては熱
伝導率が低下していることが分かる。The graph of FIG. 2 shows the result of measuring the relationship between the amount of metal powder added to CoSbx (2.7 <x <3.4) and the thermal conductivity at room temperature. As is clear from this graph, the effect of reducing the thermal conductivity is reduced by reducing the amount of the metal powder added, and the amount of the metal component added is reduced.
In samples less than 0.01 wt%, the decrease in thermal conductivity due to the addition of metal powder is not noticeable, but it can be seen that the thermal conductivity is lower than that in the comparative example.
【００２７】図３のグラフは、CoSbx (2.7＜x ＜3.4)に
対する金属粉末の添加量と、ゼーベック係数との関係を
室温にて測定した結果を示すものである。このグラフか
ら明らかなように、金属粉末の添加量を増やすことによ
りゼーベック係数は減少し、特に主成分に対する添加量
を20wt% よりも多くすると急激な低下が見られることが
分かる。The graph of FIG. 3 shows the result of measuring the relationship between the amount of metal powder added to CoSbx (2.7 <x <3.4) and the Seebeck coefficient at room temperature. As is apparent from this graph, the Seebeck coefficient decreases as the amount of the metal powder added increases, and a sharp decrease is observed particularly when the amount of the metal powder added is greater than 20 wt%.
【００２８】図４は、本発明によって分散材を添加する
ことによる熱伝導率の変化および電気伝導率の変化を示
すものであり、κ0 およびσ0 は分散材を添加しない場
合の熱伝導率および電気伝導率をそれぞれ示すものであ
る。本発明によれば、金属または合金粉末を分散させる
ことによって電気伝導率の低下を抑えながら熱伝導率を
低下させることができることがわかる。FIG. 4 shows a change in thermal conductivity and a change in electrical conductivity due to the addition of a dispersant according to the present invention. Κ0 and σ0 are thermal conductivity and electrical conductivity when no dispersant is added. It shows conductivity respectively. According to the present invention, it can be seen that by dispersing the metal or alloy powder, the thermal conductivity can be reduced while suppressing the decrease in the electrical conductivity.
【００２９】図５は、本発明による熱電変換用半導体材
料において、CoSb3 母材中に分散材を分散させた状態を
模式的に示したものである。FIG. 5 schematically shows a state in which a dispersion material is dispersed in a CoSb3 base material in the semiconductor material for thermoelectric conversion according to the present invention.
【００３０】[0030]
【発明の効果】上述したように、本発明による熱電変換
用半導体材料においては、化学組成がCoSbx (2.7＜x ＜
3.4)で表される主成分に、金属または合金粉末を添加す
ることにより熱伝導率を低下することができる。特に、
主成分に対して0.01wt% 〜20wt% の割合で混入させるこ
とにより、ゼーベック係数の低下を抑えながら熱伝導率
を低下させることができ、性能指数を効率良く改善する
ことができる。As described above, in the semiconductor material for thermoelectric conversion according to the present invention, the chemical composition is CoSbx (2.7 <x <
The thermal conductivity can be reduced by adding a metal or alloy powder to the main component represented by 3.4). In particular,
By mixing 0.01 wt% to 20 wt% with respect to the main component, the thermal conductivity can be reduced while suppressing the decrease in the Seebeck coefficient, and the figure of merit can be efficiently improved.
【００３１】また、本発明による製造方法では、安価
で、取扱が容易で、生産性の高い金属または合金粉末を
用いることができるので、汎用的な焼結法を用いて、良
好な性能指数を有する熱電変換用半導体材料を安価に効
率良く生産でき、その工業的な価値は非常に大きいもの
である。In the manufacturing method according to the present invention, a metal or alloy powder which is inexpensive, easy to handle and has high productivity can be used. The semiconductor material for thermoelectric conversion can be produced efficiently at low cost, and its industrial value is very large.
【００３２】さらに、この種の材料は、立方晶型のCoSb
3 の結晶構造を基本骨格としているため、Ｐ型とＮ型の
不純物を含有する個々の材料は同一の結晶構造を有して
いる。したがって、その熱的安定性、熱膨張率とも同一
の材料と見做せるので、粉末成形によってもＰ−Ｎ接合
の形成が容易であり、さらに室温から300 ℃以上の広い
温度範囲において化学的にも安定であり、熱的特性の劣
化が起こらず、耐熱性、成形性に優れたまた経済的にも
優れたものである。Further, this type of material is cubic type CoSb.
Since the crystal structure of No. 3 is used as a basic skeleton, each material containing P-type and N-type impurities has the same crystal structure. Therefore, it can be considered that the material has the same thermal stability and coefficient of thermal expansion, so that the PN junction can be easily formed by powder molding, and furthermore, it can be chemically formed in a wide temperature range from room temperature to 300 ° C. or more. Is also stable, does not deteriorate in thermal characteristics, is excellent in heat resistance and moldability, and is economically excellent.
【図１】 図１は、金属または合金粉末を添加していな
い従来の熱電変換用半導体材料の熱伝導率と、本発明に
よる熱電変換用半導体材料の熱伝導率とを対比して示す
グラフである。FIG. 1 is a graph showing a comparison between the thermal conductivity of a conventional thermoelectric conversion semiconductor material to which no metal or alloy powder is added and the thermal conductivity of a thermoelectric conversion semiconductor material according to the present invention. is there.
【図２】 図２は、金属または合金粉末の添加量と熱伝
導率との関係を示すグラフである。FIG. 2 is a graph showing the relationship between the amount of metal or alloy powder added and the thermal conductivity.
【図３】 図３は、金属または合金粉末の添加量と、ゼ
ーベック係数との関係を示すグラフである。FIG. 3 is a graph showing the relationship between the amount of metal or alloy powder added and the Seebeck coefficient.
【図４】 図４は、本発明によって金属または合金粉末
を添加することによる熱伝導率および電気伝導率の変化
の比率を示すグラフである。FIG. 4 is a graph showing a change ratio of a thermal conductivity and an electrical conductivity by adding a metal or alloy powder according to the present invention.
【図５】 図５は、本発明による熱電変換用半導体材料
における分散材の分散状態を模式的に示す図である。FIG. 5 is a diagram schematically showing a dispersion state of a dispersion material in the semiconductor material for thermoelectric conversion according to the present invention.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 三好 実人 愛知県名古屋市瑞穂区須田町２番56号 日 本碍子株式会社内 (72)発明者 古谷 健司 神奈川県横浜市神奈川区宝町２番地 日産 自動車株式会社内 (72)発明者 櫛引 圭子 神奈川県横浜市神奈川区宝町２番地 日産 自動車株式会社内 (72)発明者 小林 正和 神奈川県横浜市神奈川区宝町２番地 日産 自動車株式会社内 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Miyoshi Minato 2-56, Suda-cho, Mizuho-ku, Nagoya-shi, Aichi Japan Inside Nihon Insulator Co., Ltd. (72) Inventor Kenji Furuya 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa (72) Inventor Keiko Kushibiki, Nissan Motor Co., Ltd. (2) Nissan Motor Co., Ltd. (72) Inventor Masakazu Kobayashi, Nissan Motor Co., Ltd., 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa
Claims (9)
たはＮ型の熱電変換用半導体材料において、化学組成が
CoSbx (2.7＜x ＜3.4)で表される主成分に、分散材とし
て焼成温度よりも高い融点を持つ金属粉末を分散させた
ことを特徴とする熱電変換用半導体材料。1. A P-type or N-type semiconductor material for thermoelectric conversion used in a thermoelectric conversion module, wherein the chemical composition is
A semiconductor material for thermoelectric conversion, wherein a metal powder having a melting point higher than the firing temperature is dispersed as a dispersant in a main component represented by CoSbx (2.7 <x <3.4).
たはＮ型の熱電変換用半導体材料において、化学組成が
CoSbx (2.7＜x ＜3.4)で表される主成分に、分散材とし
て焼成温度よりも高い融点を持つ合金粉末を分散させた
ことを特徴とする熱電変換用半導体材料。2. A P-type or N-type semiconductor material for thermoelectric conversion used in a thermoelectric conversion module, wherein the chemical composition is
A semiconductor material for thermoelectric conversion, wherein an alloy powder having a melting point higher than a firing temperature is dispersed as a dispersant in a main component represented by CoSbx (2.7 <x <3.4).
を、主成分に対して0.01wt% 〜20wt% の割合で混入させ
たことを特徴とする請求項１または２に記載の熱電変換
用半導体材料。3. The semiconductor for thermoelectric conversion according to claim 1, wherein the metal or alloy powder as the dispersing material is mixed at a ratio of 0.01 wt% to 20 wt% with respect to the main component. material.
V, Zr, Ti, W, Mo, Cr,Cu, Ptより成る群から選択され
た金属粉末としたことを特徴とする請求項１または3 に
記載の熱電変換用半導体材料。4. The metal powder as the dispersing material, wherein Mn,
4. The thermoelectric conversion semiconductor material according to claim 1, wherein the metal powder is selected from the group consisting of V, Zr, Ti, W, Mo, Cr, Cu, and Pt.
Ni-Cr, Al-Si, MoSi2, WSi2 より成る群から選択された
合金粉末としたことを特徴とする請求項２または３に記
載の熱電変換用半導体材料。5. An WC,
4. The semiconductor material for thermoelectric conversion according to claim 2, wherein the alloy powder is an alloy powder selected from the group consisting of Ni-Cr, Al-Si, MoSi2, and WSi2.
たことを特徴とする請求項１〜５の何れかに記載の熱電
変換用半導体材料。6. The thermoelectric conversion semiconductor material according to claim 1, wherein the thermoelectric conversion semiconductor material is a sintered body.
粒径をサブミクロンから数百ミクロンとしたことを特徴
とする請求項１〜６の何れかに記載の熱電変換用半導体
材料。7. The semiconductor material for thermoelectric conversion according to claim 1, wherein a particle size of the metal or alloy powder as the dispersing material is from submicron to several hundred microns.
たはＮ型の熱電変換用半導体材料を製造するに当たり、
主成分の化学組成がCoSbx (2.7＜x ＜3.4)で表される原
料粉末と、金属または合金粉末とを混合し、所定の形状
の成形した後、還元性雰囲気または非酸化性雰囲気中に
おいて、前記金属または合金粉末の融点よりも低い温度
で焼成することを特徴とする熱電変換用半導体材料の製
造方法。8. When producing a P-type or N-type semiconductor material for thermoelectric conversion used in a thermoelectric conversion module,
A raw material powder whose chemical composition is represented by CoSbx (2.7 <x <3.4) and a metal or alloy powder are mixed and molded into a predetermined shape, and then in a reducing atmosphere or a non-oxidizing atmosphere, A method for producing a semiconductor material for thermoelectric conversion, characterized by firing at a temperature lower than the melting point of the metal or alloy powder.
を、主成分に対して0.01wt% 〜20wt% の割合で混入させ
ることを特徴とする請求項８に記載の熱電変換用半導体
材料の製造方法。9. The method for producing a semiconductor material for thermoelectric conversion according to claim 8, wherein the metal or alloy powder as the dispersing material is mixed at a ratio of 0.01 wt% to 20 wt% with respect to the main component. Method.
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|---|---|---|---|
| JP11058845A JP2000261048A (en) | 1999-03-05 | 1999-03-05 | Semiconductor material for thermoelectric conversion and manufacture of the same |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11058845A JP2000261048A (en) | 1999-03-05 | 1999-03-05 | Semiconductor material for thermoelectric conversion and manufacture of the same |
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|---|---|
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ID=13096014
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|---|---|---|---|
| JP11058845A Pending JP2000261048A (en) | 1999-03-05 | 1999-03-05 | Semiconductor material for thermoelectric conversion and manufacture of the same |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005294478A (en) * | 2004-03-31 | 2005-10-20 | Dainippon Printing Co Ltd | Thermoelectric transduction element |
| JP2008192652A (en) * | 2007-01-31 | 2008-08-21 | National Institute Of Advanced Industrial & Technology | Compound thermoelectric conversion material |
| WO2010041725A1 (en) * | 2008-10-07 | 2010-04-15 | 住友化学株式会社 | Thermoelectric conversion module and thermoelectric conversion element |
| US8394284B2 (en) | 2007-06-06 | 2013-03-12 | Toyota Jidosha Kabushiki Kaisha | Thermoelectric converter and method of manufacturing same |
| US8617918B2 (en) | 2007-06-05 | 2013-12-31 | Toyota Jidosha Kabushiki Kaisha | Thermoelectric converter and method thereof |
| US8828277B2 (en) | 2009-06-18 | 2014-09-09 | Toyota Jidosha Kabushiki Kaisha | Nanocomposite thermoelectric conversion material and method of producing the same |
-
1999
- 1999-03-05 JP JP11058845A patent/JP2000261048A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005294478A (en) * | 2004-03-31 | 2005-10-20 | Dainippon Printing Co Ltd | Thermoelectric transduction element |
| JP2008192652A (en) * | 2007-01-31 | 2008-08-21 | National Institute Of Advanced Industrial & Technology | Compound thermoelectric conversion material |
| US8617918B2 (en) | 2007-06-05 | 2013-12-31 | Toyota Jidosha Kabushiki Kaisha | Thermoelectric converter and method thereof |
| US8394284B2 (en) | 2007-06-06 | 2013-03-12 | Toyota Jidosha Kabushiki Kaisha | Thermoelectric converter and method of manufacturing same |
| WO2010041725A1 (en) * | 2008-10-07 | 2010-04-15 | 住友化学株式会社 | Thermoelectric conversion module and thermoelectric conversion element |
| US8828277B2 (en) | 2009-06-18 | 2014-09-09 | Toyota Jidosha Kabushiki Kaisha | Nanocomposite thermoelectric conversion material and method of producing the same |
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