JP2013219105A - Nanocomposite thermoelectric conversion material - Google Patents
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- 238000006243 chemical reaction Methods 0.000 title claims abstract description 47
- 239000000463 material Substances 0.000 title claims abstract description 47
- 239000002114 nanocomposite Substances 0.000 title claims abstract description 14
- 239000002245 particle Substances 0.000 claims abstract description 62
- 239000013078 crystal Substances 0.000 claims abstract description 25
- 239000011159 matrix material Substances 0.000 claims abstract description 25
- 239000002105 nanoparticle Substances 0.000 claims description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 15
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 10
- 230000000694 effects Effects 0.000 description 8
- 238000010438 heat treatment Methods 0.000 description 7
- 239000000203 mixture Substances 0.000 description 6
- 229910004298 SiO 2 Inorganic materials 0.000 description 5
- 238000005245 sintering Methods 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 238000001803 electron scattering Methods 0.000 description 4
- 239000002002 slurry Substances 0.000 description 4
- 239000000919 ceramic Substances 0.000 description 3
- 239000003638 chemical reducing agent Substances 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 239000011669 selenium Substances 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 229910052797 bismuth Inorganic materials 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000011812 mixed powder Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 238000010248 power generation Methods 0.000 description 2
- 229910052711 selenium Inorganic materials 0.000 description 2
- 229910052714 tellurium Inorganic materials 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 230000005679 Peltier effect Effects 0.000 description 1
- 230000005678 Seebeck effect Effects 0.000 description 1
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- GEIAQOFPUVMAGM-UHFFFAOYSA-N ZrO Inorganic materials [Zr]=O GEIAQOFPUVMAGM-UHFFFAOYSA-N 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- JHXKRIRFYBPWGE-UHFFFAOYSA-K bismuth chloride Chemical compound Cl[Bi](Cl)Cl JHXKRIRFYBPWGE-UHFFFAOYSA-K 0.000 description 1
- KYKAJFCTULSVSH-UHFFFAOYSA-N chloro(fluoro)methane Chemical compound F[C]Cl KYKAJFCTULSVSH-UHFFFAOYSA-N 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007123 defense Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000010335 hydrothermal treatment Methods 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 229910001404 rare earth metal oxide Inorganic materials 0.000 description 1
- 239000012279 sodium borohydride Substances 0.000 description 1
- 229910000033 sodium borohydride Inorganic materials 0.000 description 1
- 238000002490 spark plasma sintering Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- SWLJJEFSPJCUBD-UHFFFAOYSA-N tellurium tetrachloride Chemical compound Cl[Te](Cl)(Cl)Cl SWLJJEFSPJCUBD-UHFFFAOYSA-N 0.000 description 1
- 230000005676 thermoelectric effect Effects 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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Abstract
Description
本発明は、熱電変換材料から成るマトリクス中に、ナノサイズ（粒径１〜１００ｎｍ程度）のフォノン散乱粒子が分散したナノコンポジット熱電変換材料に関する。 The present invention relates to a nanocomposite thermoelectric conversion material in which nano-sized (particle size of about 1 to 100 nm) phonon scattering particles are dispersed in a matrix made of a thermoelectric conversion material.
熱電変換材料は、２つの基本的な熱電効果であるゼーベック（Ｓeebeck）効果及びペルチェ（Peltier）効果に基づき、熱エネルギと電気エネルギとの直接変換を行なうエネルギ材料である。 The thermoelectric conversion material is an energy material that performs direct conversion between thermal energy and electric energy based on the two basic thermoelectric effects, the Seebeck effect and the Peltier effect.
熱電変換材料を用いた熱電発電デバイスは、従来の発電技術に比べて、構造は簡単で、堅牢かつ耐久性が高く、可動部材は存在せず、マイクロ化が容易であり、メンテナンス不要で信頼性が高く、寿命が長く、騒音は発生せず、汚染も発生せず、低温の廃熱を利用可能であるといった多くの利点がある。 Thermoelectric power generation devices using thermoelectric conversion materials have a simple structure, robustness, high durability, no moving parts, easy microfabrication, no maintenance, and reliability compared to conventional power generation technology There are many advantages such as high life, long life, no noise, no pollution and low temperature waste heat can be used.
熱電変換材料を用いた熱電冷却デバイスも、従来の圧縮冷却技術に比べて、フロン不要で汚染は発生せず、小型化は容易で、可動部材は存在せず、騒音も発生しないなどの利点がある。 Compared to conventional compression cooling technology, thermoelectric cooling devices using thermoelectric conversion materials do not require chlorofluorocarbon, do not cause contamination, are easily downsized, have no moving parts, and do not generate noise. is there.
そのため、特に近年のエネルギ問題や環境問題の重大化に伴い、航空・宇宙、国防建設、地質及び気象観測、医療衛生、マイクロ電子などの領域や石油化工、冶金、電力工業における廃熱利用方面などの広範な用途への実用化が期待されている。 Therefore, especially in recent years, energy and environmental issues have become more serious, such as aviation / space, national defense construction, geological and meteorological observation, medical hygiene, microelectronics, etc. Is expected to be put to practical use for a wide range of applications.
熱電変換材料の性能を評価する指数として、パワーファクターＰ＝α2σおよび無次元性能指数ＺＴ＝（α2σ／κ）Ｔが用いられている。ここで、α：ゼーベック係数、σ：電気伝導率、κ：熱伝導率、Ｔ：絶対温度である。すなわち、良好な熱電特性を得るには、ゼーベック係数αおよび導電率σが高く、熱伝導率κが低いことが必要である。 As an index for evaluating the performance of the thermoelectric conversion material, a power factor P = α 2 σ and a dimensionless performance index ZT = (α 2 σ / κ) T are used. Here, α: Seebeck coefficient, σ: electrical conductivity, κ: thermal conductivity, and T: absolute temperature. That is, in order to obtain good thermoelectric properties, it is necessary that the Seebeck coefficient α and the electrical conductivity σ are high and the thermal conductivity κ is low.
熱伝導率κを低減するためには、熱伝導の担い手の一つであるフォノンを散乱させることが有効であり、熱電変換材料マトリクス中にフォノン散乱用の粒子が分散したコンポジット熱電変換材料が提唱されている。 In order to reduce the thermal conductivity κ, it is effective to scatter phonons, one of the players in heat conduction, and a composite thermoelectric conversion material in which phonon scattering particles are dispersed in a thermoelectric conversion material matrix is proposed. Has been.
特許文献1には、熱電変換材料マトリクス中に、フォノン散乱粒子としてセラミックス粒子を分散させたコンポジット熱電変換材料が提案されている。しかし、分散させたセラミックス粒子のサイズがサブミクロン〜数百ミクロンであるため、フォノン散乱効果が小さく、熱伝導率κの低下効果が不十分であった。また、フォノン散乱粒子の体積率を高めると電気伝導率σが大幅に悪化してしまし、結局、無次元性能指数ＺＴ＝（α2σ／κ）Ｔを向上させることができないという問題があった。 Patent Document 1 proposes a composite thermoelectric conversion material in which ceramic particles are dispersed as phonon scattering particles in a thermoelectric conversion material matrix. However, since the size of the dispersed ceramic particles is submicron to several hundred microns, the phonon scattering effect is small and the effect of lowering the thermal conductivity κ is insufficient. Further, when the volume fraction of phonon scattering particles is increased, the electrical conductivity σ is greatly deteriorated. As a result, the dimensionless figure of merit ZT = (α 2 σ / κ) T cannot be improved. It was.
特許文献２には、フォノン散乱粒子がマトリクス相の結晶粒内および結晶粒界に存在するナノコンポジット熱電変換材料が開示されている。この場合、熱伝導率κを大幅に低減できるが、電気伝導率σが悪化してしまい、やはり、無次元性能指数ＺＴ＝（α2σ／κ）Ｔの向上が不十分な場合があるという問題があった。 Patent Document 2 discloses a nanocomposite thermoelectric conversion material in which phonon scattering particles are present in crystal grains and matrix boundaries of a matrix phase. In this case, the thermal conductivity κ can be significantly reduced, but the electrical conductivity σ is deteriorated, and the improvement in the dimensionless figure of merit ZT = (α 2 σ / κ) T may still be insufficient. There was a problem.
本発明は、熱電変換材料マトリクス中にナノサイズのフォノン散乱粒子を分散させて熱伝導率を低減しつつ、高い電気伝導率を確保することにより、高い熱電性能を有するナノコンポジット熱電変換材料を提供することを目的とする。 The present invention provides a nanocomposite thermoelectric conversion material having high thermoelectric performance by ensuring high electrical conductivity while reducing thermal conductivity by dispersing nano-sized phonon scattering particles in a thermoelectric conversion material matrix The purpose is to do.
上記の目的を達成するために、本発明によれば、熱電変換材料から成るマトリクス中に、ナノサイズのフォノン散乱粒子が分散しているナノコンポジット熱電変換材料において、
熱電変換材料の結晶粒界にのみフォノン散乱粒子が存在することを特徴とするナノコンポジット熱電変換材料が提供される。
In order to achieve the above object, according to the present invention, in a nanocomposite thermoelectric conversion material in which nano-sized phonon scattering particles are dispersed in a matrix made of a thermoelectric conversion material,
Provided is a nanocomposite thermoelectric conversion material characterized in that phonon scattering particles are present only at crystal grain boundaries of the thermoelectric conversion material.
本発明者は、熱電変換材料マトリクスの結晶粒界にのみフォノン散乱粒子が存在することにより、熱伝導率を低減しつつ、電気伝導率を高く維持できることを新規に見出して本発明を完成させた。 The inventor of the present invention newly found out that the presence of phonon scattering particles only at the crystal grain boundaries of the thermoelectric conversion material matrix can maintain high electrical conductivity while reducing thermal conductivity, thereby completing the present invention. .
本発明においては、熱電変換材料マトリクスの結晶粒界にのみフォノン散乱粒子が存在する。なお、フォノン散乱粒子は熱電変換材料マトリクスの結晶粒界の３重点に存在してもよい。 In the present invention, phonon scattering particles exist only at the crystal grain boundaries of the thermoelectric conversion material matrix. The phonon scattering particles may exist at the triple point of the crystal grain boundary of the thermoelectric conversion material matrix.
マトリクスを構成する熱電変換材料の組成は特に限定しない。代表的な一例として、Ｂｉ、Ｓｂ、Ｔｅ、Ｓｅのうち任意の２種以上の元素から成る組成がある。マトリクス中に分散するフォノン散乱粒子については、組成を特に限定する必要はないが、典型的にはセラミックス粒子であり、例えばＳｉＯ２、ＴｉＯ２、ＺｒＯ、ＭｇＯ、Ａｌ２Ｏ３、希土類酸化物等である。 The composition of the thermoelectric conversion material constituting the matrix is not particularly limited. A typical example is a composition composed of any two or more elements of Bi, Sb, Te, and Se. The phonon scattering particles dispersed in the matrix need not be particularly limited in composition, but are typically ceramic particles such as SiO 2 , TiO 2 , ZrO, MgO, Al 2 O 3 , rare earth oxides, etc. It is.
フォノン散乱粒子の粒径は、ナノサイズすなわち１〜１００ｎｍ程度である。
熱電変換材料マトリクス中のフォノン散乱粒子の含有量は、１〜３０vol％とすることができる。少なすぎるとフォノン散乱効果が得られず、多すぎると粒界のみに存在させることが困難になる。
The particle size of the phonon scattering particles is nano-sized, that is, about 1 to 100 nm.
Content of the phonon scattering particle | grains in the thermoelectric conversion material matrix can be 1-30 vol%. If the amount is too small, the phonon scattering effect cannot be obtained. If the amount is too large, it is difficult to exist only at the grain boundary.
フォノン散乱粒子同士の間隔は、５ｎｍ以上とすることが望ましい。５ｎｍ未満であると、下記の２点で不都合が生じやすい。 The distance between the phonon scattering particles is preferably 5 nm or more. If it is less than 5 nm, inconvenience is likely to occur in the following two points.
１）一般に、粒子間隔が５ｎｍ未満となるような粒子含有量では、熱電変換材料マトリクスの焼結体を作製することが困難になる。 1) Generally, when the particle content is such that the particle interval is less than 5 nm, it becomes difficult to produce a sintered body of a thermoelectric conversion material matrix.
２）電気伝導を担うエレクトロンの波長を考慮すると、粒子間隔が５ｎｍ未満では、フォノン散乱粒子によるエレクトロンの散乱効果が大きくなり、電気伝導率が大幅に低下する虞がある。 2) Considering the wavelength of the electrons responsible for electrical conduction, if the particle spacing is less than 5 nm, the electron scattering effect by the phonon scattering particles is increased, and the electrical conductivity may be significantly reduced.
望ましくは、フォノン散乱粒子同士の間隔は１０〜１００ｎｍである。 Desirably, the distance between the phonon scattering particles is 10 to 100 nm.
＜フォノン散乱粒子を結晶粒界のみに存在させる理由＞
一般に、多結晶体においては、図１（１）に示すように、電流を担うエレクトロンは結晶粒の粒界面で一定の割合で散乱される。そのため、多結晶体の電気抵抗率は結晶粒界における界面抵抗により低下する。
<Reason for making phonon scattering particles exist only at grain boundaries>
In general, in a polycrystal, as shown in FIG. 1 (1), the electrons responsible for the current are scattered at a constant rate at the crystal grain interface. Therefore, the electrical resistivity of the polycrystal is lowered due to the interface resistance at the crystal grain boundary.
ナノサイズのフォノン散乱粒子を熱電変換材料マトリクス中に分散させる場合、図１（２）に示すように、フォノン散乱粒子（図中の●）はマトリクスの結晶粒内および／または結晶粒界に存在する。結晶粒内に存在するフォノン散乱粒子は、効果的に熱伝導率低減に寄与すると考えられる。 When nano-sized phonon scattering particles are dispersed in a thermoelectric conversion material matrix, as shown in FIG. 1 (2), phonon scattering particles (● in the figure) exist in the matrix grains and / or in the grain boundaries. To do. It is considered that the phonon scattering particles present in the crystal grains effectively contribute to the reduction of thermal conductivity.
一方で、結晶粒界に存在するフォノン散乱粒子によって、熱伝導率低減効果をある程度確保させながら、電気伝導率の低減を最小限に抑制することが可能である。これは、結晶粒界は元来エレクトロンの散乱要因となるため、結晶粒界に存在するフォノン散乱粒子によるエレクトロン散乱効果は低いためであると考えられる。 On the other hand, the phonon scattering particles existing at the crystal grain boundaries can suppress the reduction in electrical conductivity to a minimum while ensuring the thermal conductivity reduction effect to some extent. This is presumably because the crystal grain boundary originally becomes an electron scattering factor, and hence the electron scattering effect by the phonon scattering particles existing at the crystal grain boundary is low.
この点を利用して、本発明においては、図１（３）に示すように、結晶粒界にのみフォノン散乱粒子を存在させることにより、電気伝導率の低下を最小限に抑制しつつ、熱伝導率の低減効果を確保する。 By utilizing this point, in the present invention, as shown in FIG. 1 (3), the presence of phonon scattering particles only at the crystal grain boundary suppresses the decrease in electrical conductivity while minimizing the thermal conductivity. Ensure the effect of reducing conductivity.
本発明において、望ましくは、フォノン散乱粒子同士の間隔は５ｎｍ以上とする。エレクトロンの平均自由行程よりフォノン散乱粒子間隔が小さいと、エレクトロンの散乱が起き易い。したがって、エレクトロンの平均自由行程より大きい５ｎｍ以上の間隔でフォノン散乱粒子を配置することにより、電気伝導率の低下を最小限に抑制することができる。 In the present invention, preferably, the distance between the phonon scattering particles is 5 nm or more. When the phonon scattering particle interval is smaller than the electron mean free path, electron scattering is likely to occur. Therefore, by arranging the phonon scattering particles at an interval of 5 nm or more which is larger than the electron mean free path, it is possible to minimize a decrease in electrical conductivity.
下記の手順および条件にて、ＢｉＴｅ熱電変換材料から成るマトリクス中にフォノン散乱粒子としてＳｉＯ２ナノ粒子を分散させたＢｉＴｅ系ナノコンポジット熱電変換材料を作製した。 A BiTe nanocomposite thermoelectric conversion material in which SiO 2 nanoparticles were dispersed as phonon scattering particles in a matrix made of BiTe thermoelectric conversion material was prepared according to the following procedure and conditions.
（１）原料溶液の調製
塩化ビスマス（ＢｉＣｌ３）：１．８０ｇ
塩化テルル（ＴｅＣｌ４）：２．１９ｇ
シリカ（ＳｉＯ２）スラリー（アドマテックス社製、ＳｉＯ２含有量１０wt％、ＳｉＯ２粒径５ｎｍ）：２．６７ｇ
上記塩化物およびシリカスラリーをエタノール（１００ｍＬ）中に溶解させて原料溶液とした。
(1) Preparation of raw material solution Bismuth chloride (BiCl 3 ): 1.80 g
Tellurium chloride (TeCl 4 ): 2.19 g
Silica (SiO 2 ) slurry (manufactured by Admatechs, SiO 2 content 10 wt%, SiO 2 particle size 5 nm): 2.67 g
The chloride and silica slurry was dissolved in ethanol (100 mL) to obtain a raw material solution.
（２）還元剤溶液の調製
還元剤として水素化ホウ素ナトリウム（ＮａＢＨ４）２．２６ｇをエタノール（１００ｍＬ）に溶解させて酸化剤溶液とした。
(2) Preparation of reducing agent solution 2.26 g of sodium borohydride (NaBH 4 ) as a reducing agent was dissolved in ethanol (100 mL) to prepare an oxidizing agent solution.
（３）粒子混合物の作製
非酸化性雰囲気としての窒素気流下において、原料溶液を撹拌しながら還元剤溶液を滴下して塩化物の還元によりＢｉ粒子およびＴｅ粒子を生成させ、ＳｉＯ２粒子との粒子混合物のスラリーを得た。このスラリーを水、エタノールでろ過洗浄した。
(3) Preparation of particle mixture Under a nitrogen stream as a non-oxidizing atmosphere, a reducing agent solution is dropped while stirring the raw material solution to generate Bi particles and Te particles by reduction of chloride, and with SiO 2 particles A slurry of the particle mixture was obtained. This slurry was washed by filtration with water and ethanol.
（４）合金化
上記ろ過洗浄後の粒子混合物のスラリーをエタノール（１５０ｍＬ）と混合し、水熱処理（２４０℃×４８ｈ）を施して、ＢｉとＴｅとを合金化した。その後、エタノールでろ過洗浄し、窒素気流下で乾燥した。これによりＢｉＴｅ合金粒子とシリカ粒子との混合粉末を得た。
(4) Alloying The slurry of the particle mixture after filtration and washing was mixed with ethanol (150 mL) and subjected to hydrothermal treatment (240 ° C. × 48 h) to alloy Bi and Te. Then, it was filtered and washed with ethanol, and dried under a nitrogen stream. Thus, a mixed powder of BiTe alloy particles and silica particles was obtained.
（５）熱処理
上記混合粉末（２．２７ｇ）に焼結助剤としてセレン（Ｓｅ）粉末（０．０３４ｇ）を混合して、圧粉成型した後、窒素雰囲気中にて３００℃、３７０℃、４７０℃の３通りの温度で４８ｈの熱処理を施した。炉内で自然冷却後に回収した。
(5) Heat treatment After mixing selenium (Se) powder (0.034 g) as a sintering aid with the above mixed powder (2.27 g) and compacting, 300 ° C., 370 ° C. in a nitrogen atmosphere, Heat treatment was performed at three temperatures of 470 ° C. for 48 hours. It recovered after natural cooling in the furnace.
（６）焼結
放電プラズマ焼結（ＳＰＳ）により圧力５０ＭＰａで４００℃、１０ｍｉｎの焼結を行って、ナノコンポジット熱電変換材料のバルク体を得た。
(6) Sintering A bulk body of a nanocomposite thermoelectric conversion material was obtained by sintering at 400 ° C. for 10 min at a pressure of 50 MPa by spark plasma sintering (SPS).
〔比較例〕
比較のために、実施例の手順（１）において、シリカスラリーを用いない以外は、実施例と同じ条件で手順（２）〜（６）を行い、ＢｉＴｅ系熱電変換材料を作製した。ただし手順（５）の熱処理は４７０℃にて行った。
[Comparative Example]
For comparison, in the procedure (1) of the example, the steps (2) to (6) were performed under the same conditions as in the example except that the silica slurry was not used, and a BiTe-based thermoelectric conversion material was produced. However, the heat treatment of the procedure (5) was performed at 470 ° C.
＜顕微鏡組織の観察＞
実施例で作製したサンプルの組織をＴＥＭ観察した。
図２に熱処理温度に対してＴＥＭ組織を示す。
熱処理温度が３００℃の場合は、結晶粒内と結晶粒界の両方にシリカ粒子（黒い斑点）が存在することが認められた。これに対し、熱処理温度が３７０℃および４７０℃の場合は、結晶粒界のみにシリカ粒子が存在することが認められた。
いずれも、シリカ粒子の含有量は６．７vol％であった。
<Observation of microscopic structure>
The structure of the sample produced in the example was observed by TEM.
FIG. 2 shows the TEM structure with respect to the heat treatment temperature.
When the heat treatment temperature was 300 ° C., it was recognized that silica particles (black spots) existed in both the crystal grains and the crystal grain boundaries. On the other hand, when the heat treatment temperatures were 370 ° C. and 470 ° C., it was confirmed that silica particles exist only at the crystal grain boundaries.
In any case, the content of silica particles was 6.7 vol%.
＜電気伝導率の測定＞
熱処理温度４７０℃の本発明の実施例サンプルと、フォノン散乱粒子（シリカ粒子）を添加しない比較例サンプルについて、アルバック理工社製熱電特性評価装置ＺＥＭ−１にて、電気伝導率を測定した。測定結果を表１に示す。
<Measurement of electrical conductivity>
About the Example sample of this invention of 470 degreeC of heat processing, and the comparative example sample which does not add a phonon scattering particle | grain (silica particle), the electrical conductivity was measured in the thermoelectric property evaluation apparatus ZEM-1 by ULVAC-RIKO. The measurement results are shown in Table 1.
表１に示したように、電気伝導率は、本発明により結晶粒界のみにシリカを存在させた場合は３３３００Ｓ／ｍと、比較例（シリカ無添加）の場合の３７０００Ｓ／ｍに対し、９０％の電気伝導率が確保されている。 As shown in Table 1, the electrical conductivity was 90,300 S / m in the case where silica was present only at the grain boundary according to the present invention, and 37000 S / m in the comparative example (no silica added). % Electrical conductivity is ensured.
＜本発明品の評価：従来技術との対比＞
図３に、本発明の電気伝導率を従来技術（特許文献２）と比較して示す。従来技術のサンプルは、本発明の実施例と同等の熱電変換材料マトリクス中の結晶粒内および結晶粒界の両方に、本発明の実施例と同等のサイズおよび含有量のシリカ粒子を分散させた同等サンプルであり、電気伝導率は２３７００Ｓ／ｍである。これは表１の比較例（無添加）の６４％であり、本発明の実施例の９０％に比べて大きく低下している。この差は、フォノン散乱粒子としてのシリカ粒子が結晶粒内に存在することによる低下分と考えられる。
<Evaluation of the product of the present invention: Comparison with the prior art>
FIG. 3 shows the electrical conductivity of the present invention in comparison with the prior art (Patent Document 2). In the sample of the prior art, silica particles having the same size and content as those of the examples of the present invention were dispersed in both the crystal grains and the grain boundaries in the thermoelectric conversion material matrix equivalent to the examples of the present invention. An equivalent sample with an electrical conductivity of 23700 S / m. This is 64% of the comparative example (non-added) in Table 1, which is significantly lower than 90% of the example of the present invention. This difference is considered to be a decrease due to the presence of silica particles as phonon scattering particles in the crystal grains.
すなわち、本発明によりフォノン散乱粒子を熱電変換材料マトリクスの結晶粒界にのみ存在させたことによって、結晶粒内と結晶粒界の両方にフォノン散乱粒子が存在した従来技術に比べて、無添加サンプルに対する電気伝導率の確保率が９０％／６４％＝１．４０倍に向上した。 That is, by adding phonon scattering particles only at the crystal grain boundaries of the thermoelectric conversion material matrix according to the present invention, the additive-free sample is compared with the conventional technique in which phonon scattering particles exist in both the crystal grains and the crystal grain boundaries. As a result, the ratio of securing the electric conductivity with respect to was improved 90% / 64% = 1.40 times.
表２に、特許文献１に記載されている同等サンプルの電子移動度（電気伝導率に比例）を示す。フォノン散乱粒子は熱電変換材料マトリクスの結晶粒内および結晶粒界の両方に存在している。 Table 2 shows the electron mobility (proportional to the electrical conductivity) of the equivalent sample described in Patent Document 1. Phonon scattering particles are present both in the crystal grains of the thermoelectric conversion material matrix and in the grain boundaries.
表２に示したように、電子移動度は、フォノン散乱粒子無添加の場合が９．７９ｃｍ２／Ｖsecであり、フォノン散乱粒子の含有量４．０vol％〜９．１vol％で存在する場合が６．１７〜６．９９ｃｍ２／Ｖsecであり、６３％〜７１％に低下している。 As shown in Table 2, the electron mobility is 9.79 cm 2 / Vsec when no phonon scattering particles are added, and may exist at a phonon scattering particle content of 4.0 vol% to 9.1 vol%. 6.17 to 6.99 cm 2 / Vsec, decreasing to 63% to 71%.
したがって、本発明によりフォノン散乱粒子を熱電変換材料マトリクスの結晶粒界にのみ存在させたことによって、無添加サンプルに対する電気伝導率の確保率が９０％／７１％〜９０％／６３％＝１．２７倍〜１．４３倍に向上した。 Therefore, by ensuring that the phonon scattering particles are present only at the crystal grain boundaries of the thermoelectric conversion material matrix according to the present invention, the electrical conductivity securing ratio for the additive-free sample is 90% / 71% to 90% / 63% = 1. It improved from 27 times to 1.43 times.
本発明によれば、熱電変換材料マトリクス中にナノサイズのフォノン散乱粒子を分散させて熱伝導率を低減しつつ、高い電気伝導率を確保することにより、高い熱電性能を有するナノコンポジット熱電変換材料が提供される。 According to the present invention, nano-sized phonon scattering particles are dispersed in a thermoelectric conversion material matrix to reduce the thermal conductivity while ensuring high electrical conductivity, thereby providing a nanocomposite thermoelectric conversion material having high thermoelectric performance. Is provided.
Claims (2)
熱電変換材料の結晶粒界にのみフォノン散乱粒子が存在することを特徴とするナノコンポジット熱電変換材料。 In a nanocomposite thermoelectric conversion material in which nano-sized phonon scattering particles are dispersed in a matrix made of a thermoelectric conversion material,
A nanocomposite thermoelectric conversion material characterized in that phonon scattering particles exist only at the crystal grain boundaries of the thermoelectric conversion material.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016164935A (en) * | 2015-03-06 | 2016-09-08 | トヨタ自動車株式会社 | Method for producing thermoelectric conversion material |
| JP2017050505A (en) * | 2015-09-04 | 2017-03-09 | 株式会社日立製作所 | Thermoelectric conversion material and thermoelectric conversion module |
| JP2018190906A (en) * | 2017-05-10 | 2018-11-29 | 株式会社日立製作所 | Thermoelectric conversion material and thermoelectric conversion module |
| JP2019012717A (en) * | 2017-06-29 | 2019-01-24 | 三菱マテリアル株式会社 | Thermoelectric conversion material, and method of manufacturing thermoelectric conversion material |
| CN110622326A (en) * | 2017-05-19 | 2019-12-27 | 日东电工株式会社 | Semiconductor sintered body, electric and electronic component, and method for producing semiconductor sintered body |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08199281A (en) * | 1995-01-20 | 1996-08-06 | Yamaha Corp | Production of thermoelectric refrigerating material and thermoelectric transducing element |
| JPH10242535A (en) * | 1997-02-27 | 1998-09-11 | Central Res Inst Of Electric Power Ind | Thermoelectric material and its manufacture |
| JPH10303468A (en) * | 1997-04-23 | 1998-11-13 | Matsushita Electric Ind Co Ltd | Thermoelectric material and its manufacture |
| JP2000261047A (en) * | 1999-03-05 | 2000-09-22 | Ngk Insulators Ltd | Semiconductor material for thermoelectric conversion and manufacture of the same |
| JP2001007414A (en) * | 1999-06-23 | 2001-01-12 | Sumitomo Special Metals Co Ltd | Manufacture of thermoelectric converting element |
| JP2001185767A (en) * | 1999-12-22 | 2001-07-06 | Yamaguchi Industrial Promotion Foundation | Thermoelectric conversion material and control method of its thermoelectric characteristic |
| JP2001223395A (en) * | 2000-02-09 | 2001-08-17 | Natl Inst Of Advanced Industrial Science & Technology Meti | Manufacturing method od thermoelectric material |
| JP2005183528A (en) * | 2003-12-17 | 2005-07-07 | Toyota Motor Corp | Thermoelectric conversion element and its manufacturing method |
| JP2008305919A (en) * | 2007-06-06 | 2008-12-18 | Toyota Motor Corp | Thermoelectric conversion element and manufacturing method therefor |
| US20110100409A1 (en) * | 2009-11-05 | 2011-05-05 | Samsung Electronics Co., Ltd. | Thermoelectric nano-composite, and thermoelectric module and thermoelectric apparatus including the thermoelectric nano-composite |
| JP2011204835A (en) * | 2010-03-25 | 2011-10-13 | Toyota Central R&D Labs Inc | Composite thermoelectric material and method for manufacturing the same |
-
2012
- 2012-04-05 JP JP2012086301A patent/JP6189582B2/en not_active Expired - Fee Related
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08199281A (en) * | 1995-01-20 | 1996-08-06 | Yamaha Corp | Production of thermoelectric refrigerating material and thermoelectric transducing element |
| JPH10242535A (en) * | 1997-02-27 | 1998-09-11 | Central Res Inst Of Electric Power Ind | Thermoelectric material and its manufacture |
| JPH10303468A (en) * | 1997-04-23 | 1998-11-13 | Matsushita Electric Ind Co Ltd | Thermoelectric material and its manufacture |
| JP2000261047A (en) * | 1999-03-05 | 2000-09-22 | Ngk Insulators Ltd | Semiconductor material for thermoelectric conversion and manufacture of the same |
| JP2001007414A (en) * | 1999-06-23 | 2001-01-12 | Sumitomo Special Metals Co Ltd | Manufacture of thermoelectric converting element |
| JP2001185767A (en) * | 1999-12-22 | 2001-07-06 | Yamaguchi Industrial Promotion Foundation | Thermoelectric conversion material and control method of its thermoelectric characteristic |
| JP2001223395A (en) * | 2000-02-09 | 2001-08-17 | Natl Inst Of Advanced Industrial Science & Technology Meti | Manufacturing method od thermoelectric material |
| JP2005183528A (en) * | 2003-12-17 | 2005-07-07 | Toyota Motor Corp | Thermoelectric conversion element and its manufacturing method |
| JP2008305919A (en) * | 2007-06-06 | 2008-12-18 | Toyota Motor Corp | Thermoelectric conversion element and manufacturing method therefor |
| US20110100409A1 (en) * | 2009-11-05 | 2011-05-05 | Samsung Electronics Co., Ltd. | Thermoelectric nano-composite, and thermoelectric module and thermoelectric apparatus including the thermoelectric nano-composite |
| JP2011204835A (en) * | 2010-03-25 | 2011-10-13 | Toyota Central R&D Labs Inc | Composite thermoelectric material and method for manufacturing the same |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016164935A (en) * | 2015-03-06 | 2016-09-08 | トヨタ自動車株式会社 | Method for producing thermoelectric conversion material |
| JP2017050505A (en) * | 2015-09-04 | 2017-03-09 | 株式会社日立製作所 | Thermoelectric conversion material and thermoelectric conversion module |
| JP2018190906A (en) * | 2017-05-10 | 2018-11-29 | 株式会社日立製作所 | Thermoelectric conversion material and thermoelectric conversion module |
| CN110622326A (en) * | 2017-05-19 | 2019-12-27 | 日东电工株式会社 | Semiconductor sintered body, electric and electronic component, and method for producing semiconductor sintered body |
| CN110622326B (en) * | 2017-05-19 | 2023-12-12 | 日东电工株式会社 | Semiconductor sintered body, electric and electronic component, and method for producing semiconductor sintered body |
| JP2019012717A (en) * | 2017-06-29 | 2019-01-24 | 三菱マテリアル株式会社 | Thermoelectric conversion material, and method of manufacturing thermoelectric conversion material |
| JP7121227B2 (en) | 2017-06-29 | 2022-08-18 | 三菱マテリアル株式会社 | Thermoelectric conversion material and method for producing thermoelectric conversion material |
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