JP2006237460A - Process for producing thermoelectric material - Google Patents

Process for producing thermoelectric material Download PDF

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JP2006237460A
JP2006237460A JP2005052840A JP2005052840A JP2006237460A JP 2006237460 A JP2006237460 A JP 2006237460A JP 2005052840 A JP2005052840 A JP 2005052840A JP 2005052840 A JP2005052840 A JP 2005052840A JP 2006237460 A JP2006237460 A JP 2006237460A
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thermoelectric material
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thermoelectric
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Akihiro Nozue
章浩 野末
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Panasonic Holdings Corp
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Matsushita Electric Industrial Co Ltd
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<P>PROBLEM TO BE SOLVED: To provide a process for producing a thermoelectric material in which the figure of merit is enhanced by employing a thermoelectric material of ultrafine particles having single nano size thereby reducing thermal conductivity significantly. <P>SOLUTION: The process for producing a thermoelectric material comprises a step for forming a deposition film by simultaneous deposition method where the thermoelectric material and a polymer are heated simultaneously and deposited while performing vapor phase mixture, a step for collecting the thermoelectric material by removing the polymer from the deposition film, and a step for sintering the collected thermoelectric material wherein a thermoelectric material having an ultrafine crystal grain size can be produced by vapor phase mixture. Furthermore, the figure of merit can be enhanced because phonon thermal conductivity is reduced sharply by phonon dispersion when the thermoelectric material is sintered. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、熱を電気に変換する熱電材料の作製方法に関するものである。   The present invention relates to a method for producing a thermoelectric material that converts heat into electricity.

一般に、熱電材料はＰｂＴｅ系、スクッテルダイト系、ペロブスカイト系等種々の材料が存在するが、室温付近で最も大きな能力を発揮する材料としてはＢｉ２Ｔｅ３、Ｂｉ２Ｓｅ３及びＳｂ２Ｔｅ３のようなＶ−ＶＩ族系等の熱電材料があり、センサー素子や光素子、ＬＳＩ基板などの半導体回路、宇宙ステーションで使用される電子機器の冷却、レーザダイオード等の精密温度制御が要求されるところに使用されている。 In general, there are various thermoelectric materials such as PbTe, skutterudite, and perovskite, but Bi 2 Te 3 , Bi 2 Se 3, and Sb 2 Te 3 are materials that exhibit the greatest ability near room temperature. Thermoelectric materials such as V-VI group, such as sensor elements, optical elements, semiconductor circuits such as LSI substrates, cooling of electronic equipment used in space stations, precise temperature control of laser diodes, etc. are required However, it is used.

また、民生用としてはその低騒音特性、低振動性を生かし、ホテル用冷蔵庫やワインセラーの冷却に用いられている。逆に、熱から電気を生み出す熱電発電にも用いられており、特に室温付近での廃熱利用はＢｉ２Ｔｅ３系に勝るものは存在しない。その他、室温付近で比較的大きな能力を示すものとしては、強相関熱電子系のＮａＣｏ２Ｏ４やハーフホイスラー系熱電材料があるが、前記Ｂｉ２Ｔｅ３にはまだ及ばない。 For consumer use, it is used to cool hotel refrigerators and wine cellars, taking advantage of its low noise characteristics and low vibration. On the contrary, it is also used for thermoelectric power generation that generates electricity from heat, and the use of waste heat especially near room temperature does not surpass the Bi 2 Te 3 system. In addition, examples of a relatively large capacity near room temperature include strongly correlated thermoelectron-based NaCo 2 O 4 and half-Heusler-based thermoelectric materials, which are still not as good as those of Bi 2 Te 3 .

室温付近で最も大きな能力を発揮するＢｉ２Ｔｅ３化合物は、菱面体結晶の単位胞中にＢｉとＴｅの原子をそれぞれ２と３個を含む層状構造で物理的性質に大きな異方性を持つ。この構造は六方晶表示のｃ軸方向にＴｅ原子層の重なりが３組存在し、このＴｅ−Ｔｅ原子の結合はファン・デル・ワールス結合のため、共有結合やイオン結合およびそれらの混合結合で結合した他の原子間の結合より著しく弱く容易に劈開する。また、ｃ軸方向に垂直（ｃ面に平行）な方向で電気特性が高い。 The Bi 2 Te 3 compound that exhibits the greatest ability near room temperature has a large anisotropy in physical properties with a layered structure containing 2 and 3 atoms of Bi and Te, respectively, in the unit cell of the rhombohedral crystal. . In this structure, there are three pairs of Te atom layers overlapping in the c-axis direction of hexagonal crystal display, and this Te-Te atom bond is a van der Waals bond, so it is a covalent bond, an ionic bond or a mixed bond thereof. It is significantly weaker than the bond between other bonded atoms and easily cleaves. Also, the electrical characteristics are high in a direction perpendicular to the c-axis direction (parallel to the c-plane).

熱電材料の特性を表す性能指数Ｚは、次式で示すようにゼーベック係数Ｓの２乗と電気伝導率σの積を熱伝導率κで割ったもので表される。   The figure of merit Z representing the characteristics of the thermoelectric material is represented by the product of the square of the Seebeck coefficient S and the electrical conductivity σ divided by the thermal conductivity κ, as shown in the following equation.

Ｚ＝Ｓ２・σ／κ
したがって、性能指数Ｚを大きくするためには、Ｓ２・σ（ゼーベック係数Ｓの２乗と電気伝導率σの積）を大きくし、かつ熱伝導率κを小さくする必要がある。 Z = S 2 · σ / κ
Therefore, in order to increase the figure of merit Z, it is necessary to increase S 2 · σ (the product of the square of the Seebeck coefficient S and the electrical conductivity σ) and decrease the thermal conductivity κ.

一般によく使われるブリッジマン法などで一方向凝固させて作製した溶製材料は、単結晶材料ほどではないが、結晶の配向性が整っている。そのため、電気伝導率は高い。しかし、結晶粒径が非常に大きいため、フォノンの散乱による熱伝導率減少効果は小さく、熱伝導率は大きくなる。また、ｃ面で劈開しやすいため材料強度が非常に低い。   The melted material produced by unidirectional solidification by the Bridgman method or the like that is generally used has a crystal orientation that is not as high as that of a single crystal material. Therefore, electrical conductivity is high. However, since the crystal grain size is very large, the effect of decreasing the thermal conductivity due to phonon scattering is small and the thermal conductivity is large. Moreover, since it is easy to cleave at c surface, material strength is very low.

一方、メカニカルアロイング法やガスアトマイズ法により熱電材料を微細化し、その微細結晶を一方向加圧焼結することで作製する焼結材料は、材料強度が優れ、かつ、加圧方向に対し垂直（直角）な方向にｃ面が揃うことが知られている（例えば、特許文献１参照）。   On the other hand, a sintered material produced by refining a thermoelectric material by mechanical alloying or gas atomization and unidirectionally pressing and sintering the fine crystal has excellent material strength and is perpendicular to the pressing direction ( It is known that c-planes are aligned in a (right angle) direction (see, for example, Patent Document 1).

また、この微細な粒子の粒界におけるフォノン散乱により熱伝導率を低減させることができる。単純に言えば、粒径が微細なほどフォノン散乱効果は大きく、それだけフォノン熱伝導率は減少する。結晶粒径を微細にする方法としてはこの他、ガスアトマイズ法や超急冷法等がある（例えば、特許文献２参照）。   Further, the thermal conductivity can be reduced by phonon scattering at the grain boundaries of the fine particles. Simply put, the finer the particle size, the greater the phonon scattering effect, and the smaller the phonon thermal conductivity. Other methods for reducing the crystal grain size include a gas atomizing method and a super rapid cooling method (see, for example, Patent Document 2).

さらに、これらの方法は、焼結材料の結晶配向性が、ブリッジマン法と比べ非常に低く、電気伝導率は低減するため、結果的に相殺され、性能指数が一方向凝固材を越えることはない。   Furthermore, these methods have a much lower crystal orientation of the sintered material than the Bridgman method, and the electrical conductivity is reduced, so that they are offset as a result and the figure of merit exceeds that of the unidirectional solidified material. Absent.

そこで、微細結晶焼結体の結晶配向性を向上する手段として、熱間塑性変形によるすえこみ鍛造や熱間押出成形によるものがある（例えば、特許文献３参照）。
特開昭６２−２６４６８２号公報 特開２００２−２６４０３号公報 特開平１０−１７８２１８号公報 Therefore, as means for improving the crystal orientation of the fine crystal sintered body, there are methods by upset forging by hot plastic deformation and hot extrusion (for example, see Patent Document 3).
Japanese Patent Laid-Open No. 62-264682 JP 2002-26403 A JP-A-10-178218

しかしながら、上記特許文献１や特許文献２の微細粒子作製方法では、結晶の平均粒径が１〜３０μｍ程度であり、フォノン散乱効果は十分ではなく、不純物が混入しやすい。   However, in the fine particle manufacturing methods of Patent Document 1 and Patent Document 2 described above, the average particle diameter of crystals is about 1 to 30 μm, the phonon scattering effect is not sufficient, and impurities are easily mixed.

また、上記特許文献３の熱間塑性変形を行うと、結晶配向性は向上するが、その過程で数μｍの粒径が数十μｍまで粒成長をおこすため、フォノン散乱効果の低減により熱伝導率が増加し、結晶配向性を揃えても性能指数が低下してしまうという問題があった。   Further, when the hot plastic deformation described in Patent Document 3 is performed, the crystal orientation is improved, but in the process, the grain size of several μm grows to several tens of μm, so that the heat conduction is reduced by reducing the phonon scattering effect. However, there is a problem that the figure of merit decreases even if the crystal orientation is uniform.

本発明の目的は、熱電材料を超微細化することで、熱伝導率低減効果を著しく向上させ、さらに熱間塑性変形の際にも結晶粒径を小さく保つことを可能とすることで、熱伝導率を低減したまま結晶配向性を向上させ、性能指数を向上させる熱電材料の作製方法を提供することにある。   The object of the present invention is to remarkably improve the thermal conductivity reduction effect by making the thermoelectric material ultrafine, and also to keep the crystal grain size small even during hot plastic deformation. An object of the present invention is to provide a method for producing a thermoelectric material that improves crystal orientation while reducing conductivity and improves a figure of merit.

上記従来の課題を解決するために、本発明の熱電材料の作製方法は、熱電材料の作製方法であって、前記熱電材料と高分子を同時に加熱することで気相混合しながら蒸着する同時蒸発法によって蒸着膜を作製する蒸着過程と、前記蒸着膜から前記高分子を除去することで前記熱電材料を回収する回収工程と、回収した前記熱電材料を焼結する焼結工程からなることを特徴とするものである。   In order to solve the above-mentioned conventional problems, the method for producing a thermoelectric material of the present invention is a method for producing a thermoelectric material, in which vapor deposition is performed while vapor-phase mixing is performed by simultaneously heating the thermoelectric material and a polymer. A vapor deposition process for producing a vapor deposition film by a method, a recovery process for recovering the thermoelectric material by removing the polymer from the vapor deposition film, and a sintering process for sintering the recovered thermoelectric material. It is what.

これによって、気相混合により、超微細な結晶粒径を有する熱電材料を作製することができる。また、前記熱電材料を焼結することで、フォノン散乱が大きくなり、フォノン熱伝導率が大きく低減するため、性能指数の向上を図ることができる。   Thus, a thermoelectric material having an ultrafine crystal grain size can be produced by gas phase mixing. Moreover, by sintering the thermoelectric material, phonon scattering is increased and phonon thermal conductivity is greatly reduced, so that the figure of merit can be improved.

さらに、高分子中に熱電材料が取り込まれるため、高分子を除去するまで、熱電材料が酸素に触れる機会が激減し、酸化による熱電材料の性能低下を防止するとともに不純物の混入が少なく、性能の変化も少ない。   Furthermore, since the thermoelectric material is taken into the polymer, the opportunity for the thermoelectric material to come into contact with oxygen is drastically reduced until the polymer is removed. There is little change.

また、本発明の熱電材料の作製方法は、前記熱電材料がシングルナノ粒子であることを特徴とするものである。   The method for producing a thermoelectric material of the present invention is characterized in that the thermoelectric material is a single nanoparticle.

すなわち、１０ｎｍ以下のシングルナノ粒子では粒界面積は著しく大きくなり、熱伝導率も大きく低減するとともに、逆ホールペッチ効果により硬度が低下し、また粒界滑りによる変形が起こりやすくなり、加工性が向上する。   In other words, with single nanoparticles of 10 nm or less, the grain boundary area is remarkably increased, the thermal conductivity is greatly reduced, the hardness is lowered by the reverse Hall Petch effect, and deformation due to grain boundary sliding is likely to occur, thereby improving workability. To do.

これにより、超微細な熱電材料を作製することができ、熱伝導率が大きく減少し、熱電性能が向上した熱電材料の作製方法を提供することができる。   Thereby, an ultrafine thermoelectric material can be produced, and a method for producing a thermoelectric material with greatly reduced thermal conductivity and improved thermoelectric performance can be provided.

本発明の熱電材料の作製方法は、熱電材料と高分子を同時に加熱し気相混合して蒸着する同時蒸発法によって作製することにより、シングルナノレベルの超微細な粒径を有する熱電材料を作製でき、粒界散乱によるフォノン散乱効果を非常に有効に発揮し、熱伝導率を大きく低減させることができ、性能指数の向上を図ることができる。また、蒸着時に高分子膜内に取り込まれるため、酸素との接触を防止することができ、酸素と接触する時間を出来るだけ減少させることで、熱電材料の酸化を防ぐことができるとともに不純物の混入が少なく、性能の変化も少ない。   The method for producing a thermoelectric material of the present invention is a thermoelectric material having an ultrafine particle size of a single nano level by producing a thermoelectric material and a polymer by simultaneous evaporation method in which vapor deposition is performed by gas phase mixing and vapor deposition. The phonon scattering effect due to grain boundary scattering can be exhibited very effectively, the thermal conductivity can be greatly reduced, and the figure of merit can be improved. In addition, since it is taken into the polymer film during vapor deposition, contact with oxygen can be prevented, and by reducing the time for contact with oxygen as much as possible, oxidation of the thermoelectric material can be prevented and impurities can be mixed. There is little change in performance.

また、本発明の熱電材料の作製方法は、超微細な粒子のため、熱間塑性変形を行う際、粒成長により粒径が大きくなっても、十分粒径が小さく、配向性向上による電気伝導率の向上と、フォノン散乱による熱伝導率の低減効果で、性能指数は著しく向上する。   In addition, since the thermoelectric material manufacturing method of the present invention is an ultrafine particle, when performing hot plastic deformation, even if the particle size increases due to grain growth, the particle size is sufficiently small, and the electric conduction due to improved orientation is achieved. The figure of merit is remarkably improved by the improvement of the rate and the effect of reducing the thermal conductivity by phonon scattering.

請求項１に記載の発明は、熱電材料と高分子を同時に加熱することで気相混合しながら蒸着する同時蒸発法によって蒸着膜を作製する蒸着過程と、前記蒸着膜から前記高分子を除去することで前記熱電材料を回収する回収工程と、回収した前記熱電材料を焼結する焼結工程からなる熱電材料の作製方法である。   The invention according to claim 1 is a vapor deposition process in which a vapor deposition film is formed by simultaneous evaporation method in which a thermoelectric material and a polymer are heated at the same time to perform vapor phase mixing, and the polymer is removed from the vapor deposition film. This is a method for producing a thermoelectric material comprising a recovery step of recovering the thermoelectric material and a sintering step of sintering the recovered thermoelectric material.

かかる方法により、気相混合により、他の作製方法では得るのが困難な１μｍ未満の超微細な結晶粒径を有する熱電材料を作製することができる。前記熱電材料を焼結することで、フォノン散乱が大きく、フォノン熱伝導率が大きく低減するため、性能指数の向上を図ることができる。   By this method, a thermoelectric material having an ultrafine crystal grain size of less than 1 μm, which is difficult to obtain by other production methods, can be produced by gas phase mixing. By sintering the thermoelectric material, phonon scattering is large and phonon thermal conductivity is greatly reduced, so that the figure of merit can be improved.

さらに、かかる方法によれば、高分子中に熱電材料が取り込まれるため、高分子を除去するまで、熱電材料が酸素に触れる機会が激減し、酸化による熱電材料の性能低下を防止するとともに不純物の混入が少なく、性能の変化も少ない。   Further, according to such a method, since the thermoelectric material is taken into the polymer, the opportunity for the thermoelectric material to contact oxygen is drastically reduced until the polymer is removed. Little contamination and little change in performance.

また、蒸着工程は真空もしくは不活性ガス、希ガス中で行うのが好ましく、さらに、熱電材料の回収工程は、真空もしくは不活性ガス、希ガス中で行うのが好ましい。   Further, the vapor deposition step is preferably performed in a vacuum, an inert gas, or a rare gas, and the thermoelectric material recovery step is preferably performed in a vacuum, an inert gas, or a rare gas.

また、焼結工程はホットプレス法、冷間プレス法、ＳＰＳ焼結法、ＨＩＰ法、ＣＩＰ法等特に限定するものではなく、また、焼結工程を複数行っても良い。   The sintering process is not particularly limited, such as a hot pressing method, a cold pressing method, an SPS sintering method, an HIP method, and a CIP method, and a plurality of sintering steps may be performed.

請求項２記載の発明は、前記回収工程にて回収された前記熱電材料を、シングルナノ粒子としたものである。   The invention according to claim 2 is the one in which the thermoelectric material recovered in the recovery step is a single nanoparticle.

かかることにより、１０ｎｍ以下のシングルナノ粒子では粒界面積は著しく大きくなり、熱伝導率も大きく低減するとともに、逆ホールペッチ効果により硬度が低下し、また粒界滑りによる変形が起こりやすくなり、加工性が向上する。   As a result, in single nanoparticles of 10 nm or less, the grain interfacial area is remarkably increased, the thermal conductivity is greatly reduced, the hardness is lowered due to the reverse Hall Petch effect, and deformation due to grain boundary sliding is likely to occur. Will improve.

請求項３記載の発明は、前記高分子を熱可塑性高分子としたもので、熱可塑性高分子は、蒸着しやすくかつ溶剤に溶けやすいため、工程の簡素化が図れる。   The invention according to claim 3 is the one in which the polymer is a thermoplastic polymer, and the thermoplastic polymer can be easily deposited and dissolved in a solvent, so that the process can be simplified.

さらに、前記高分子の種類は特に限定するものではないが、分子量が低く、単純な構造の高分子の方が蒸着させやすく、例えばポリビニルアルコールなどが適している。   Furthermore, the type of the polymer is not particularly limited, but a polymer having a lower molecular weight and a simple structure is easier to deposit, and for example, polyvinyl alcohol is suitable.

請求項４記載の発明は、前記回収工程において、前記高分子を溶剤で溶解することにより前記高分子を除去するものである。   According to a fourth aspect of the present invention, in the recovery step, the polymer is removed by dissolving the polymer with a solvent.

かかることにより、溶解後良く洗浄することで、高分子を高精度に除去できるため、焼結時に高分子が溶着するといった熱電材料の性能低下への影響を排除することができる。   In this way, since the polymer can be removed with high precision by washing well after dissolution, it is possible to eliminate the influence on the performance degradation of the thermoelectric material such that the polymer is deposited during sintering.

溶剤の種類は特に限定しないが、熱電材料に影響を及ぼさず、かつ、高分子を速やかに溶解するものが好ましい。   The type of the solvent is not particularly limited, but a solvent that does not affect the thermoelectric material and dissolves the polymer quickly is preferable.

請求項５記載の発明は、ビスマス、アンチモン、テルル、セレンからなる群から少なくとも二つ以上を含有する熱電材料を用いた熱電材料の作製方法とすることにより、室温付近において熱電材料の性能を最大限に向上させることが可能となり、冷却効率の優れた熱電材料を提供することができる。   The invention according to claim 5 maximizes the performance of the thermoelectric material near room temperature by using a thermoelectric material manufacturing method using a thermoelectric material containing at least two or more from the group consisting of bismuth, antimony, tellurium and selenium. The thermoelectric material with excellent cooling efficiency can be provided.

請求項６記載の発明は、前記焼結工程において、少なくとも前記熱電材料を熱間塑性変形させる変形工程を含むものとしたもので、Ｂｉ２Ｔｅ３系の熱電材料は異方性があり、外部からの変形工程により、結晶配向性が向上し、熱電性能の向上が図れる。 The invention according to claim 6 includes at least a deformation step in which the thermoelectric material is hot plastically deformed in the sintering step, and the Bi 2 Te 3 series thermoelectric material is anisotropic and external From the deformation process, the crystal orientation is improved and the thermoelectric performance can be improved.

請求項７記載の発明は、前記熱間塑性変形を熱間圧延加工で行うもので、圧延加工により結晶が圧延方向に延伸され、結晶が配向することで熱電性能が向上する。   According to the seventh aspect of the invention, the hot plastic deformation is performed by hot rolling, and the crystal is stretched in the rolling direction by the rolling and the crystal is oriented to improve the thermoelectric performance.

請求項８記載の発明は、前記熱間塑性変形を熱間押出加工で行うもので、押出加工により押出方向と平行な方向に結晶配向性が向上し、熱電性能が向上する。   In the invention according to claim 8, the hot plastic deformation is performed by hot extrusion, and the crystal orientation is improved in the direction parallel to the extrusion direction by the extrusion, and the thermoelectric performance is improved.

請求項９記載の発明は、前記熱間塑性変形をＥＣＡＥ加工で行うもので、前記熱間塑性変形を、ＥＣＡＥ（Ｅｑｕａｌ−Ｃｈａｎｎｅｌ Ａｎｇｕｌａｒ Ｅｘｔｒｕｓｉｏｎ）加工とすることにより、強力な剪断応力により、結晶の微細化が起こるため、熱間加工による粒成長の影響を抑制し、高性能な熱電材料を提供することができる。   The invention according to claim 9 is the one in which the hot plastic deformation is performed by ECAE processing, and the hot plastic deformation is ECAE (Equal-Channel Angular Extraction) processing, whereby a strong shear stress is applied to the crystal. Since miniaturization occurs, the influence of grain growth due to hot working can be suppressed, and a high-performance thermoelectric material can be provided.

以下、本発明の実施の形態について、図面を参照しながら説明する。なお、この実施の形態によって本発明が限定されるものではない。   Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

（実施の形態１）
図１は、本発明の実施の形態１における同時蒸着法の模式図である。 (Embodiment 1)
FIG. 1 is a schematic diagram of a co-evaporation method according to Embodiment 1 of the present invention.

図１において、チャンバー１内に熱電材料２と高分子３がそれぞれ別の容器２ａ・３ａに入れられて設置されている。チャンバー１内は、希ガス４で置換され、かつ、減圧雰囲気に調整されている。各容器２ａ・３ａには、加熱用のヒーター５がそれぞれ設けられており、このヒーター５によって熱電材料２と高分子３を加熱することにより、両者は気化し、気相状態でそれぞれ混合し、チャンバー１内において蒸着膜６を形成する。   In FIG. 1, a thermoelectric material 2 and a polymer 3 are placed in separate containers 2 a and 3 a in a chamber 1. The inside of the chamber 1 is replaced with a rare gas 4 and adjusted to a reduced pressure atmosphere. Each of the containers 2a and 3a is provided with a heater 5 for heating. By heating the thermoelectric material 2 and the polymer 3 with the heater 5, they are vaporized and mixed in a gas phase state, A vapor deposition film 6 is formed in the chamber 1.

図２は、本発明の実施の形態１における蒸着膜の模式図である。   FIG. 2 is a schematic diagram of the deposited film in the first embodiment of the present invention.

図２において、蒸着膜６は、高分子蒸着膜７中に、熱電材料微粒子８が分散されている状態にある。熱電材料微粒子８は、気相中で混合されたため、非常に微細なシングルナノサイズの粒子を形成する。   In FIG. 2, the vapor deposition film 6 is in a state where the thermoelectric material fine particles 8 are dispersed in the polymer vapor deposition film 7. Since the thermoelectric material fine particles 8 are mixed in the gas phase, very fine single nano-sized particles are formed.

図３は、本発明の実施の形態１における熱電材料微粒子の回収工程を示す模式図である。   FIG. 3 is a schematic diagram showing a thermoelectric material microparticle recovery step in Embodiment 1 of the present invention.

図３において、同図（ａ）の如く蒸着膜６を容器９に満たした溶剤１０に浸すことにより、高分子蒸着膜７だけを溶解する。その結果、同図（ｂ）の如く熱電材料微粒子８を分離・回収することができる。   In FIG. 3, only the polymer vapor deposition film 7 is dissolved by immersing the vapor deposition film 6 in the solvent 10 filled in the container 9 as shown in FIG. As a result, the thermoelectric material fine particles 8 can be separated and recovered as shown in FIG.

これらの工程は、希ガス雰囲気など酸素がない状態で行い、そして、回収した熱電材料微粒子８は良く乾燥させる。   These steps are performed in the absence of oxygen such as a rare gas atmosphere, and the recovered thermoelectric material fine particles 8 are dried well.

図４は、本発明の実施の形態１における放電プラズマ焼結による焼結工程を示す模式図である。   FIG. 4 is a schematic diagram showing a sintering process by spark plasma sintering in Embodiment 1 of the present invention.

図４において、パルス通電加圧焼結装置（放電プラズマ焼結装置）１１は、上下一対であり、それぞれに電極１２と加圧セル１６を有する。上述の回収工程にて回収した熱電材料微粒子８を、ダイス１４内に設けられた空間１７に封入し、上下にパンチ１３を設ける。加圧セル１６は、上下移動可能で、熱電材料微粒子８を充填後、加圧セル１６を図中矢印Ａ・Ｂで示すように相対する方向（上下方向）に移動させ、熱電材料微粒子８を所定圧力で一軸方向（図示上下方向）に加圧しながら、電極１２にパルス電流１５を通電する。その結果、熱電材料微粒子８にもパルス電流が流れる。このように熱電材料微粒子８にもパルス電流１５を流すことで、熱電材料微粒子８の内部にジュール熱を発生させ、そのジュール熱の発生により熱電材料微粒子８内から発熱させる。   In FIG. 4, a pulse energization pressure sintering apparatus (discharge plasma sintering apparatus) 11 is a pair of upper and lower sides, each having an electrode 12 and a pressure cell 16. The thermoelectric material fine particles 8 recovered in the above-described recovery step are enclosed in a space 17 provided in the die 14 and punches 13 are provided on the upper and lower sides. The pressurization cell 16 can move up and down, and after filling the thermoelectric material fine particles 8, the pressurization cell 16 is moved in the opposite direction (up and down direction) as indicated by arrows A and B in the figure, and the thermoelectric material fine particles 8 are moved. A pulse current 15 is applied to the electrode 12 while pressurizing in a uniaxial direction (vertical direction in the figure) with a predetermined pressure. As a result, a pulse current also flows through the thermoelectric material fine particles 8. In this way, by applying the pulse current 15 to the thermoelectric material fine particles 8, Joule heat is generated inside the thermoelectric material fine particles 8, and heat is generated from the thermoelectric material fine particles 8 by the generation of the Joule heat.

そして、熱電材料微粒子８の温度が所定温度に到達した後、所定時間、温度を保持し、熱電材料を焼結する。   Then, after the temperature of the thermoelectric material fine particles 8 reaches a predetermined temperature, the temperature is maintained for a predetermined time, and the thermoelectric material is sintered.

以上により作製された熱電材料（焼結体）は、熱伝導率を低減させ、熱電性能を向上させることができる。   The thermoelectric material (sintered body) produced as described above can reduce thermal conductivity and improve thermoelectric performance.

熱電材料および高分子の種類を変え、上述の方法にて作製した熱電材料焼結体の性能評価結果を実施例１から実施例３に示す。比較例１と比較例２としてメカニカルアロイング法で作製した熱電材料をパルス通電加圧焼結法で作製したものを用いた。   Example 1 to Example 3 show the performance evaluation results of the thermoelectric material sintered bodies produced by the above-described methods by changing the types of the thermoelectric material and polymer. As Comparative Example 1 and Comparative Example 2, a thermoelectric material produced by a mechanical alloying method and produced by a pulse current pressure sintering method was used.

熱電材料として（Ｂｉ２Ｔｅ３）２０（Ｓｂ２Ｔｅ３）８０を用い、ポリビニルアルコールと同時蒸着法で超微細粒子を含んだ蒸着膜６を作製し、アセトンでポリビニルアルコールを除去した。このとき結晶粒径は約５〜１０ｎｍであった。そして、６７３Ｋ、５０ＭＰａ、１０分間のパルス通電加圧焼結法で作製した焼結体の熱電性能を測ったところ、ゼーベック係数が２．２×１０−４［Ｖ／Ｋ］、電気伝導率が５．７×１０４［１／Ω・ｍ］、熱伝導率が０．８７［Ｗ／ｍ・Ｋ］、性能指数は３．１７×１０−３［１／Ｋ］であった。 Using (Bi 2 Te 3 ) 20 (Sb 2 Te 3 ) 80 as a thermoelectric material, a vapor deposition film 6 containing ultrafine particles was prepared by simultaneous vapor deposition with polyvinyl alcohol, and the polyvinyl alcohol was removed with acetone. At this time, the crystal grain size was about 5 to 10 nm. And when the thermoelectric performance of the sintered compact produced by 673K, 50MPa, and the pulse-current pressurization sintering method for 10 minutes was measured, Seebeck coefficient was 2.2 * 10 < -4 > [V / K], and electrical conductivity was. The thermal conductivity was 5.7 × 10 4 [1 / Ω · m], the thermal conductivity was 0.87 [W / m · K], and the figure of merit was 3.17 × 10 −3 [1 / K].

このことは、フォノン散乱により熱伝導率が低減したと考えられる。   This is considered that the thermal conductivity was reduced by phonon scattering.

熱電材料として（Ｂｉ２Ｔｅ３）２５（Ｓｂ２Ｔｅ３）７５を用い、ポリスチレンと同時蒸着法で超微細粒子を含んだ蒸着膜６を作製し、トルエンでポリスチレンを除去した。このとき結晶粒径は約８〜１５ｎｍであった。そして、６７３Ｋ、５０ＭＰａ、１０分間パルス通電加圧焼結法で作製した焼結体の熱電性能を測ったところゼーベック係数が２．１×１０−４［Ｖ／Ｋ］、電気伝導率が５．５×１０４［１／Ω・ｍ］、熱伝導率が０．８３［Ｗ／ｍ・Ｋ］、性能指数は２．９２×１０−３［１／Ｋ］であった。 Using (Bi 2 Te 3 ) 25 (Sb 2 Te 3 ) 75 as a thermoelectric material, a vapor deposition film 6 containing ultrafine particles was prepared by simultaneous vapor deposition with polystyrene, and the polystyrene was removed with toluene. At this time, the crystal grain size was about 8 to 15 nm. And when the thermoelectric performance of the sintered compact produced by the 673K, 50MPa, pulse current pressurization sintering method for 10 minutes was measured, Seebeck coefficient was 2.1 * 10 < -4 > [V / K], and electrical conductivity was 5. It was 5 × 10 4 [1 / Ω · m], the thermal conductivity was 0.83 [W / m · K], and the figure of merit was 2.92 × 10 −3 [1 / K].

このことは、フォノン散乱により熱伝導率が低減したと考えられる。   This is considered that the thermal conductivity was reduced by phonon scattering.

熱電材料として（Ｂｉ２Ｔｅ３）９０（Ｂｉ２Ｓｅ３）１０を用い、ポリビニルアルコールと同時蒸着法で超微細粒子を含んだ蒸着膜６を作製し、アセトンでポリビニルアルコールを除去した。このとき結晶粒径は約４〜１０ｎｍであった。そして、６７３Ｋ、５０ＭＰａ、１０分間パルス通電加圧焼結法で作製した焼結体の熱電性能を測ったところゼーベック係数が−２．３×１０−４［Ｖ／Ｋ］、電気伝導率が３．５×１０４［１／Ω・ｍ］、熱伝導率が０．８９［Ｗ／ｍ・Ｋ］、性能指数は２．０８×１０−３［１／Ｋ］であった。 Using (Bi 2 Te 3 ) 90 (Bi 2 Se 3 ) 10 as a thermoelectric material, a vapor deposition film 6 containing ultrafine particles was prepared by simultaneous vapor deposition with polyvinyl alcohol, and the polyvinyl alcohol was removed with acetone. At this time, the crystal grain size was about 4 to 10 nm. And when the thermoelectric performance of the sintered compact produced by the 673K, 50MPa, 10 minutes pulse-current pressurization sintering method was measured, Seebeck coefficient was -2.3x10 < -4 > [V / K], and electrical conductivity was 3. .5 × 10 4 [1 / Ω · m], the thermal conductivity of 0.89 [W / m · K] , the performance index was 2.08 × 10 -3 [1 / K ].

このことは、フォノン散乱により熱伝導率が低減したと考えられる。   This is considered that the thermal conductivity was reduced by phonon scattering.

（実施の形態２）
図５は、本発明の実施の形態２における熱間圧延加工の模式図である。 (Embodiment 2)
FIG. 5 is a schematic diagram of hot rolling in Embodiment 2 of the present invention.

図５において、本実施の形態２における熱間圧延加工は、ダイス１８とパンチ１９と熱電材料８の圧粉体２０を用い、圧延体２１を得る加工である。図５の（ａ）は熱間圧延加工前の状態を、同図（ｂ）は熱間圧延加工後の状態を表している。   In FIG. 5, the hot rolling process in the second embodiment is a process for obtaining a rolled body 21 using a die 18, a punch 19, and a green compact 20 of the thermoelectric material 8. FIG. 5A shows a state before hot rolling, and FIG. 5B shows a state after hot rolling.

以上のように構成された熱間圧延加工について、以下その動作を説明する。   About the hot rolling process comprised as mentioned above, the operation | movement is demonstrated below.

まず、ダイス１８中にパンチ１９で上下を挟む形で、実施の形態１に示す方法により得た熱電材料微粒子８を入れ、パンチ１９を加圧することで圧粉体２０を作製、設置する。   First, the thermoelectric material fine particles 8 obtained by the method shown in Embodiment 1 are put in a die 18 with the punch 19 sandwiched between the upper and lower sides, and the green compact 20 is produced and installed by pressurizing the punch 19.

そして、昇温装置（図示せず）にて昇温後、パンチ１９を上下方向から加圧する事で、圧粉体２０は加圧方向と直角方向に圧延され、その結果、圧延体２１が得られる。   Then, after raising the temperature with a temperature raising device (not shown), the green compact 20 is rolled in a direction perpendicular to the pressing direction by pressing the punch 19 from above and below, and as a result, a rolled body 21 is obtained. It is done.

以上により作製された熱電材料（圧延体２１）は、熱伝導率を低減させるとともに、結晶配向性が向上し、熱電性能を向上させることができる。   The thermoelectric material (rolled body 21) produced as described above can reduce the thermal conductivity, improve the crystal orientation, and improve the thermoelectric performance.

上述の熱間圧延加工で作製した熱電材料焼結体の性能評価結果を実施例４に示す。   Example 4 shows the performance evaluation results of the thermoelectric material sintered body produced by the hot rolling process described above.

熱電材料として（Ｂｉ２Ｔｅ３）２０（Ｓｂ２Ｔｅ３）８０を用い、ポリビニルアルコールと同時蒸着法で超微細粒子を含んだ蒸着膜６を作製し、アセトンでポリビニルアルコールを除去した。このとき結晶粒径は約５〜１０ｎｍであった。６７３Ｋで加熱し、熱間圧延加工で作製した焼結体の熱電性能を測ったところゼーベック係数が１．９×１０−４［Ｖ／Ｋ］、電気伝導率が８．６×１０４［１／Ω・ｍ］、熱伝導率が０．９３［Ｗ／ｍ・Ｋ］、性能指数は３．３４×１０−３［１／Ｋ］であった。 Using (Bi 2 Te 3 ) 20 (Sb 2 Te 3 ) 80 as a thermoelectric material, a vapor deposition film 6 containing ultrafine particles was prepared by simultaneous vapor deposition with polyvinyl alcohol, and the polyvinyl alcohol was removed with acetone. At this time, the crystal grain size was about 5 to 10 nm. When the thermoelectric performance of the sintered body produced by hot rolling was measured by heating at 673 K, the Seebeck coefficient was 1.9 × 10 −4 [V / K], and the electrical conductivity was 8.6 × 10 4 [1. / Ω · m], thermal conductivity was 0.93 [W / m · K], and the figure of merit was 3.34 × 10 −3 [1 / K].

このことは、フォノン散乱により熱伝導率が低減したとともに配向性が向上したと考えられる。   This is considered that the thermal conductivity was reduced by phonon scattering and the orientation was improved.

（実施の形態３）
図６は、本発明の実施の形態３における熱間押出加工の模式図である。 (Embodiment 3)
FIG. 6 is a schematic diagram of hot extrusion processing in Embodiment 3 of the present invention.

図６において、本実施の形態３における熱間圧延加工は、内部に熱電材料微粒子８の圧粉体２４を充填する空間２３を備え、底面に空間２３より小径の開口部２６を設けた金型２２と、空間２３内の熱電材料微粒子８を加圧するパンチ２５を用いて行われ、開口部２６より押出成型品２７を得る加工である。   In FIG. 6, the hot rolling process according to the third embodiment includes a die 23 having a space 23 filled with a green compact 24 of thermoelectric material fine particles 8 and having an opening 26 having a smaller diameter than the space 23 on the bottom surface. 22 and a punch 25 that pressurizes the thermoelectric material fine particles 8 in the space 23, and a process of obtaining an extruded product 27 from the opening 26.

図６の（ａ）は熱間押出加工前の状態を、（ｂ）は熱間押出加工後の状態を表している。   6A shows a state before hot extrusion, and FIG. 6B shows a state after hot extrusion.

次に、上記図６における熱間押出加工動作について説明する。   Next, the hot extrusion processing operation in FIG. 6 will be described.

まず、予め圧粉装置（図示せず）にて熱電材料微粒子８を粉砕・圧縮し、圧粉体２４を形成する。そして、金型２２の空間２３内に、圧粉体２４を充填・設置する。   First, the thermoelectric material fine particles 8 are pulverized and compressed in advance by a compacting device (not shown) to form a compact 24. Then, the green compact 24 is filled and installed in the space 23 of the mold 22.

そして、昇温装置（図示せず）にて圧粉体２４を加熱昇温し、その後、パンチ２５を図中下方向へ加圧する。   Then, the green compact 24 is heated and heated by a temperature raising device (not shown), and then the punch 25 is pressurized downward in the drawing.

その結果、圧粉体２４は、金型２２内の空間２３で加圧され、金型２２下部の開口部２６より押出成形品２７として排出される。   As a result, the green compact 24 is pressurized in the space 23 in the mold 22 and is discharged as an extruded product 27 from the opening 26 under the mold 22.

以上のようにして作製された熱電材料（押出成形品２７）は、熱伝導率を低減させるとともに、結晶配向性が向上し、熱電性能を向上させることができる。   The thermoelectric material (extruded product 27) produced as described above can reduce thermal conductivity, improve crystal orientation, and improve thermoelectric performance.

上記熱間押出加工で作製した熱電材料焼結体（押出成形品２７）の性能評価結果を実施例５に示す。   Example 5 shows the performance evaluation results of the thermoelectric material sintered body (extruded product 27) produced by the hot extrusion process.

熱電材料として（Ｂｉ２Ｔｅ３）２０（Ｓｂ２Ｔｅ３）８０を用い、ポリビニルアルコールと同時蒸着法で超微細粒子を含んだ蒸着膜を作製し、アセトンでポリビニルアルコールを除去した。このとき結晶粒径は約５〜１０ｎｍであった。６７３Ｋで加熱し、熱間押出加工で作製した焼結体の熱電性能を測ったところゼーベック係数が１．９×１０−４［Ｖ／Ｋ］、電気伝導率が９．３×１０４［１／Ω・ｍ］、熱伝導率が０．９８［Ｗ／ｍ・Ｋ］、性能指数は３．４３×１０−３［１／Ｋ］であった。 Using (Bi 2 Te 3 ) 20 (Sb 2 Te 3 ) 80 as a thermoelectric material, a vapor deposition film containing ultrafine particles was prepared by simultaneous vapor deposition with polyvinyl alcohol, and the polyvinyl alcohol was removed with acetone. At this time, the crystal grain size was about 5 to 10 nm. When the thermoelectric performance of the sintered body produced by hot extrusion was measured by heating at 673 K, the Seebeck coefficient was 1.9 × 10 −4 [V / K], and the electrical conductivity was 9.3 × 10 4 [1. / Ω · m], the thermal conductivity was 0.98 [W / m · K], and the figure of merit was 3.43 × 10 −3 [1 / K].

このことは、フォノン散乱により熱伝導率が低減したとともに配向性が向上したと考えられる。   This is considered that the thermal conductivity was reduced by phonon scattering and the orientation was improved.

（実施の形態４）
図７は、本発明の実施の形態４におけるＥＣＡＥ（Ｅｑｕａｌ−Ｃｈａｎｎｅｌ Ａｎｇｕｌａｒ Ｅｘｔｒｕｓｉｏｎ）と称される加工（以下、ＥＣＡＥ加工と称す）の模式図である。 (Embodiment 4)
FIG. 7 is a schematic diagram of a process called ECAE (Equal-Channel Angular Extension) (hereinafter referred to as ECAE process) in Embodiment 4 of the present invention.

図７において、本実施の形態４におけるＥＣＡＥ加工は、両端に入り口２９ａ側と出口２９ｂを有し、入り口２９ａと出口２９ｂの方向が角度θ異なるように形成された空間２９を内部に有する金型２８と、空間２９内に充填された熱電材料微粒子８の圧粉体３０を加圧するパンチ３１を用いて行われ、出口２９ｂより加圧された圧粉体３０を得る加工である。   In FIG. 7, the ECAE processing in the fourth embodiment is a mold having an entrance 29 a side and an exit 29 b at both ends, and a space 29 formed so that the directions of the entrance 29 a and the exit 29 b are different from each other by an angle θ. 28 and the punch 31 that pressurizes the green compact 30 of the thermoelectric material fine particles 8 filled in the space 29 to obtain the green compact 30 pressurized from the outlet 29b.

次に、上記図７におけるＥＣＡＥ加工動作について説明する。   Next, the ECAE processing operation in FIG. 7 will be described.

まず、予め予め圧粉装置（図示せず）にて熱電材料微粒子８を粉砕・圧縮し、圧粉体２４を形成する。そして、金型２８の空間２９内に、圧粉体３０を充填・設置する。   First, the thermoelectric material fine particles 8 are pulverized and compressed in advance by a compacting device (not shown) to form a compact 24 in advance. Then, the green compact 30 is filled and installed in the space 29 of the mold 28.

そして、昇温装置（図示せず）にて圧粉体３０を加熱昇温し、その後、パンチ３１を図中下方向へ加圧する。   Then, the green compact 30 is heated and heated by a temperature raising device (not shown), and then the punch 31 is pressurized downward in the drawing.

その結果、圧粉体３０は、金型２８内の空間２９で加圧され、金型２８の出口２９ｂより斜め下方向に押し出される。この押し出される際に、圧粉体３０には非常に大きな剪断応力がかかり、それにより圧粉体３０は微細化されたまま押し出される。ここで、出口２９ｂ側の穴径を入り口２９ａ側の穴径より小さくすることでさらに配向性は向上する。   As a result, the green compact 30 is pressurized in the space 29 in the mold 28 and is pushed obliquely downward from the outlet 29 b of the mold 28. At the time of the extrusion, a very large shear stress is applied to the green compact 30, so that the green compact 30 is extruded while being miniaturized. Here, the orientation is further improved by making the hole diameter on the outlet 29b side smaller than the hole diameter on the inlet 29a side.

以上のようにして作製された熱電材料（出口２９ｂから排出された圧粉体３０）は、熱伝導率を低減させるとともに、結晶配向性が向上し、熱電性能をさらに向上させることができる。   The thermoelectric material (the green compact 30 discharged from the outlet 29b) manufactured as described above can reduce the thermal conductivity, improve the crystal orientation, and further improve the thermoelectric performance.

上記熱間押出加工で作製した熱電材料焼結体（出口２９ｂから排出された圧粉体３０）の性能評価結果を実施例６に示す。   Example 6 shows the performance evaluation results of the thermoelectric material sintered body (the green compact 30 discharged from the outlet 29b) produced by the hot extrusion process.

熱電材料として（Ｂｉ２Ｔｅ３）２０（Ｓｂ２Ｔｅ３）８０を用い、ポリビニルアルコールと同時蒸着法で超微細粒子を含んだ蒸着膜を作製し、アセトンでポリビニルアルコールを除去した。このとき結晶粒径は約５〜１０ｎｍであった。６７３Ｋで加熱し、ＥＣＡＥ加工で作製した焼結体の熱電性能を測ったところゼーベック係数が１．９×１０−４［Ｖ／Ｋ］、電気伝導率が９．０×１０４［１／Ω・ｍ］、熱伝導率が０．９１［Ｗ／ｍ・Ｋ］、性能指数は３．５７×１０−３［１／Ｋ］であった。 Using (Bi 2 Te 3 ) 20 (Sb 2 Te 3 ) 80 as a thermoelectric material, a vapor deposition film containing ultrafine particles was prepared by simultaneous vapor deposition with polyvinyl alcohol, and the polyvinyl alcohol was removed with acetone. At this time, the crystal grain size was about 5 to 10 nm. When the thermoelectric performance of the sintered body produced by ECAE processing was measured by heating at 673 K, the Seebeck coefficient was 1.9 × 10 −4 [V / K], and the electrical conductivity was 9.0 × 10 4 [1 / Ω. M], thermal conductivity was 0.91 [W / m · K], and the figure of merit was 3.57 × 10 −3 [1 / K].

このことは、フォノン散乱により熱伝導率が低減したとともに配向性が向上したと考えられる。   This is considered that the thermal conductivity was reduced by phonon scattering and the orientation was improved.

次に本発明の気体吸着材および断熱体に対する比較例を示す。評価方法は上記各実施例に準じた方法である。   Next, the comparative example with respect to the gas adsorbent of this invention and a heat insulating body is shown. The evaluation method is a method according to each of the above examples.

（比較例１）
熱電材料として（Ｂｉ２Ｔｅ３）２０（Ｓｂ２Ｔｅ３）８０を用い、メカニカルアロイング法で焼結体を作製した。このとき結晶粒径は約２〜３０μｍであった。 (Comparative Example 1)
A sintered body was produced by a mechanical alloying method using (Bi 2 Te 3 ) 20 (Sb 2 Te 3 ) 80 as a thermoelectric material. At this time, the crystal grain size was about 2 to 30 μm.

そして、６７３Ｋ、５０ＭＰａ、１０分間のパルス通電加圧焼結法で作製した焼結体の熱電性能を測ったところ、ゼーベック係数が２．２×１０−４［Ｖ／Ｋ］、電気伝導率が５．９×１０４［１／Ω・ｍ］、熱伝導率が１．０１［Ｗ／ｍ・Ｋ］、性能指数は２．８３×１０−３［１／Ｋ］であった。 And when the thermoelectric performance of the sintered compact produced by 673K, 50MPa, and the pulse-current pressurization sintering method for 10 minutes was measured, Seebeck coefficient was 2.2 * 10 < -4 > [V / K], and electrical conductivity was. The thermal conductivity was 5.9 × 10 4 [1 / Ω · m], the thermal conductivity was 1.01 [W / m · K], and the figure of merit was 2.83 × 10 −3 [1 / K].

（比較例２）
熱電材料として（Ｂｉ２Ｔｅ３）９０（Ｂｉ２Ｓｅ３）１０を用い、メカニカルアロイング法で焼結体を作製した。このとき結晶粒径は約２〜２８μｍであった。 (Comparative Example 2)
A sintered body was produced by a mechanical alloying method using (Bi 2 Te 3 ) 90 (Bi 2 Se 3 ) 10 as a thermoelectric material. At this time, the crystal grain size was about 2 to 28 μm.

そして、６７３Ｋ、５０ＭＰａ、１０分間のパルス通電加圧焼結法で作製した焼結体の熱電性能を測ったところゼーベック係数が−２．１×１０−４［Ｖ／Ｋ］、電気伝導率が３．４×１０４［１／Ω・ｍ］、熱伝導率が１．０９［Ｗ／ｍ・Ｋ］、性能指数は１．３８×１０−３［１／Ｋ］であった。 Then, 673 K, 50 MPa, the Seebeck coefficient was measured the thermoelectric performance of the sintered body produced by the pulse current pressure sintering method 10 minutes -2.1 × 10 -4 [V / K ], the electrical conductivity It was 3.4 × 10 4 [1 / Ω · m], the thermal conductivity was 1.09 [W / m · K], and the figure of merit was 1.38 × 10 −3 [1 / K].

以上のように、本発明にかかる熱電材料の作製方法は、超微細なシングルナノサイズの粒径を有する熱電材料を作製することにより、熱伝導率の低減を図ることができ、優れた熱電性能を有する熱電材料を作製可能なものであり、冷凍冷蔵庫および冷凍機器や、センサー素子や光素子、ＬＳＩ基板などの半導体回路、レーザダイオード等の精密温度制御などのあらゆる冷却用途や、熱電発電に適用できる。   As described above, the method for producing a thermoelectric material according to the present invention can reduce thermal conductivity by producing a thermoelectric material having an ultrafine single nano-size particle size, and has excellent thermoelectric performance. Thermoelectric materials can be manufactured, and can be applied to freezing refrigerators and refrigeration equipment, sensor devices, optical devices, semiconductor circuits such as LSI substrates, precision temperature control such as laser diodes, and thermoelectric power generation it can.

本発明の熱電材料の作製方法にかかる実施の形態１における同時蒸着法の模式図Schematic diagram of co-evaporation method in Embodiment 1 according to the method for producing a thermoelectric material of the present invention 同実施の形態１における蒸着膜の模式図Schematic diagram of the deposited film in the first embodiment （ａ）同実施の形態１における熱電材料微粒子の回収工程における熱電材料微粒子の分離前の模式図（ｂ）同回収工程における熱電材料微粒子の分離後の模式図(A) Schematic diagram before separation of thermoelectric material particles in the recovery step of thermoelectric material particles in the first embodiment (b) Schematic diagram after separation of thermoelectric material particles in the recovery step 同実施の形態１における放電プラズマ焼結による焼結工程を示す模式図Schematic diagram showing a sintering process by spark plasma sintering in the first embodiment （ａ）本発明の実施の形態２における熱間圧延加工前の状態を示す模式図（ｂ）同熱間圧延加工後の状態を示す模式図(A) Schematic diagram showing the state before hot rolling in Embodiment 2 of the present invention (b) Schematic diagram showing the state after hot rolling （ａ）本発明の実施の形態３における熱間押出加工の加工前の状態を示す模式図（ｂ）同熱間押出加工の加工後の状態を示す模式図(A) The schematic diagram which shows the state before the process of the hot extrusion process in Embodiment 3 of this invention (b) The schematic diagram which shows the state after the process of the same hot extrusion process 本発明の実施の形態４におけるＥＣＡＥ加工の模式図Schematic diagram of ECAE processing in Embodiment 4 of the present invention

符号の説明Explanation of symbols

１ チャンバー
２ 熱電材料
３ 高分子
４ 希ガス
５ ヒーター
６ 蒸着膜
７ 高分子蒸着膜
８ 熱電材料微粒子
９ 容器
１０ 溶剤
１１ 放電プラズマ焼結装置
１２ 電極
１３ パンチ
１４ ダイス
１５ パルス電流
１６ 加圧セル
１７ 空間
１８ ダイス
１９ パンチ
２０ 圧粉体
２１ 圧延体
２２ 金型
２３ 空間
２４ 圧粉体
２５ パンチ
２６ 開口部
２７ 押出成型品
２８ 金型
２９ 空間
３０ 圧粉体
３１ パンチ 1 Chamber 2 Thermoelectric Material 3 Polymer 4 Noble Gas 5 Heater 6 Vapor Deposition Film 7 Polymer Vapor Deposition Film 8 Thermoelectric Material Fine Particles 9 Container 10 Solvent 11 Discharge Plasma Sintering Device 12 Electrode 13 Punch 14 Dice 15 Pulse Current 16 Pressurized Cell 17 Space 18 Die 19 Punch 20 Compact 21 Rolled body 22 Mold 23 Space 24 Compact 25 Punch 26 Opening 27 Extrusion product 28 Mold 29 Space 30 Compact 31 Punch

Claims (9)

熱電材料と高分子を同時に加熱することで気相混合しながら蒸着する同時蒸発法によって蒸着膜を作製する蒸着過程と、前記蒸着膜から前記高分子を除去することで前記熱電材料を回収する回収工程と、回収した前記熱電材料を焼結する焼結工程からなる熱電材料の作製方法。   A vapor deposition process for producing a vapor deposition film by a co-evaporation method in which vapor deposition is performed while gas phase mixing is performed by simultaneously heating a thermoelectric material and a polymer, and recovery for recovering the thermoelectric material by removing the polymer from the vapor deposition film. A method for producing a thermoelectric material comprising a step and a sintering step of sintering the recovered thermoelectric material. 前記回収工程にて回収された前記熱電材料が、シングルナノ粒子である請求項１に記載の熱電材料の作製方法。   The method for producing a thermoelectric material according to claim 1, wherein the thermoelectric material recovered in the recovery step is a single nanoparticle. 前記高分子を熱可塑性高分子とした請求項１または２に記載の熱電材料の作製方法。   The method for producing a thermoelectric material according to claim 1, wherein the polymer is a thermoplastic polymer. 前記回収工程において、前記高分子を溶剤で溶解することにより前記高分子を除去する請求項１から３のいずれか一項に記載の熱電材料の作製方法。   The method for producing a thermoelectric material according to any one of claims 1 to 3, wherein in the recovery step, the polymer is removed by dissolving the polymer with a solvent. ビスマス、アンチモン、テルル、セレンからなる群から少なくとも二つ以上を含有する熱電材料を用いた請求項１から４のいずれか一項に記載の熱電材料の作製方法。   The method for producing a thermoelectric material according to any one of claims 1 to 4, wherein a thermoelectric material containing at least two from the group consisting of bismuth, antimony, tellurium, and selenium is used. 前記焼結工程において、少なくとも前記熱電材料を熱間塑性変形させる変形工程を含む請求項１から５のいずれか一項に記載の熱電材料の作製方法。   The method for producing a thermoelectric material according to claim 1, wherein the sintering step includes at least a deformation step in which the thermoelectric material is hot plastically deformed. 前記熱間塑性変形を熱間圧延加工で行う請求項６に記載の熱電材料の作製方法。   The method for producing a thermoelectric material according to claim 6, wherein the hot plastic deformation is performed by hot rolling. 前記熱間塑性変形を熱間押出加工で行う請求項６に記載の熱電材料の作製方法。   The method for producing a thermoelectric material according to claim 6, wherein the hot plastic deformation is performed by hot extrusion. 前記熱間塑性変形をＥＣＡＥ加工で行う請求項６に記載の熱電材料の作製方法。   The method for producing a thermoelectric material according to claim 6, wherein the hot plastic deformation is performed by ECAE processing.
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