JP2006100683A - Thermoelectric conversion material for titanium oxide - Google Patents
Thermoelectric conversion material for titanium oxide Download PDFInfo
- Publication number
- JP2006100683A JP2006100683A JP2004286811A JP2004286811A JP2006100683A JP 2006100683 A JP2006100683 A JP 2006100683A JP 2004286811 A JP2004286811 A JP 2004286811A JP 2004286811 A JP2004286811 A JP 2004286811A JP 2006100683 A JP2006100683 A JP 2006100683A
- Authority
- JP
- Japan
- Prior art keywords
- thermoelectric conversion
- less
- conversion material
- sintered body
- volume
- 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.)
- Withdrawn
Links
Landscapes
- Compositions Of Oxide Ceramics (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
Description
本発明は、熱電変換材料に関する。より詳しくはチタン酸化物からなるｎ型の熱電変換材料に関する。 The present invention relates to a thermoelectric conversion material. More specifically, the present invention relates to an n-type thermoelectric conversion material made of titanium oxide.
熱電発電は熱電効果（ゼーベック効果）により熱源を用いて発電する技術である。熱電発電は、地熱や焼却炉の熱など種々の熱源を利用することができ、熱電発電装置には可動部分が無いので故障しにくく連続運転が容易なので、熱電発電は実用化可能な環境保全型の発電として期待されている。この熱電発電には、熱電効果を示す熱電変換材料が必要であり、金属元素の酸化物からなる熱電変換材料が検討されている。熱電発電を行うには、ｎ型の熱電変換材料からなるｎ型発電体とｐ型の熱電変換材料からなるｐ型発電体とを接合して用いる。このｐ型とｎ型のうち、特にｎ型の熱電変換材料として、高い性能を有するものが求められている。 Thermoelectric power generation is a technique for generating electricity using a heat source by the thermoelectric effect (Seebeck effect). Thermoelectric power generation can use various heat sources such as geothermal heat and heat from incinerators, and since there are no moving parts in the thermoelectric power generation device, it is difficult to malfunction and continuous operation is easy. Is expected to generate electricity. This thermoelectric power generation requires a thermoelectric conversion material exhibiting a thermoelectric effect, and a thermoelectric conversion material composed of an oxide of a metal element has been studied. In order to perform thermoelectric power generation, an n-type power generator made of an n-type thermoelectric conversion material and a p-type power generator made of a p-type thermoelectric conversion material are joined and used. Among the p-type and n-type, materials having high performance are particularly required as n-type thermoelectric conversion materials.
ここで、熱電変換材料の性能は、次の示す性能指数（Ｚ）により決められており、この性能指数が高いほど性能の高い熱電変換材料とされている。
性能指数＝ゼーベック係数の２乗×電気伝導度／熱伝導度
Here, the performance of the thermoelectric conversion material is determined by the following figure of merit (Z). The higher the figure of merit, the higher the performance of the thermoelectric conversion material.
Figure of merit = square of Seebeck coefficient x electrical conductivity / thermal conductivity
この性能指数が高く、ｎ型の熱電変換材料としてチタン酸化物が検討されており、ＴｉＯ1.94、ＴｉＯ1.88、ＴｉＯ1.86が提案されている（例えば、非特許文献１参照。）が、２９８Ｋにおける性能指数はそれぞれ０．０９６、０．０７１、０．０８６（単位は×１０-3／Ｋ）であり、さらに高い性能指数を有するチタン酸化物からなる熱電変換材料が求められていた。 Although this figure of merit is high, titanium oxide has been studied as an n-type thermoelectric conversion material, and TiO 1.94 , TiO 1.88 , and TiO 1.86 have been proposed (see, for example, Non-Patent Document 1). The indexes are 0.096, 0.071, and 0.086 (units are × 10 −3 / K), respectively, and a thermoelectric conversion material made of titanium oxide having a higher performance index has been demanded.
本発明の目的は、熱電変換における性能指数が高く、チタン酸化物からなるｎ型の熱電変換材料を提供することにある。 An object of the present invention is to provide an n-type thermoelectric conversion material having a high figure of merit in thermoelectric conversion and made of titanium oxide.
本発明はかかる課題を解決するために、不定比酸化チタンからなるｎ型の熱電変換材料について鋭意検討した結果、特定の不定比を有する酸化チタンを用いた焼結体が高い性能指数を示すことを見出し、本発明を完成させるに到った。 In order to solve this problem, the present invention has been intensively studied on an n-type thermoelectric conversion material composed of non-stoichiometric titanium oxide, and as a result, a sintered body using titanium oxide having a specific non-stoichiometric ratio exhibits a high figure of merit. As a result, the present invention has been completed.
すなわち本発明は、式ＴｉＯxで示される不定比酸化チタンであり、ｘの値が１．８９以上１．９４未満または１．９４より大きく２．００未満であり、Ｘ線回折において、２６．０°±０．３°、２６．８°±０．３°、２７．９°±０．１°、２８．２°±０．１°の各々の位置にピークを示す結晶構造を有する不定比酸化チタンからなることを特徴とするｎ型の熱電変換焼結体材料を提供する。 That is, the present invention is non-stoichiometric titanium oxide represented by the formula TiO x , the value of x is 1.89 or more and less than 1.94 or more than 1.94 and less than 2.00. Indefinite having a crystal structure showing a peak at each position of 0 ° ± 0.3 °, 26.8 ° ± 0.3 °, 27.9 ° ± 0.1 °, 28.2 ° ± 0.1 ° An n-type thermoelectric conversion sintered material comprising a specific titanium oxide is provided.
本発明の酸化物からなるｎ型熱電変換材料は安価なチタンのみを原料とした単純な組成を有し、製造も容易であり、高い性能指数を示し、熱電変換装置に本発明のｎ型熱電変換材料を用いれば、安価な安定した熱電変換装置となるので、本発明は工業的に極めて重要ある。 The n-type thermoelectric conversion material comprising the oxide of the present invention has a simple composition using only inexpensive titanium as a raw material, is easy to manufacture, exhibits a high figure of merit, and is used in a thermoelectric conversion device. If a conversion material is used, it becomes an inexpensive and stable thermoelectric conversion device, so the present invention is extremely important industrially.
本発明のｎ型の熱電変換材料は、式ＴｉＯxで示される不定比酸化チタンであり、ｘの値が１．８９以上１．９４未満または１．９４より大きく２．００未満であり、Ｘ線回折において２６．０°±０．３°、２６．８°±０．３°、２７．９°±０．１°、２８．２°±０．１°の各々の位置にピークを有する結晶構造を有するものからなることを特徴とする。 The n-type thermoelectric conversion material of the present invention is non-stoichiometric titanium oxide represented by the formula TiO x , and the value of x is 1.89 or more and less than 1.94 or more than 1.94 and less than 2.00, and X It has a peak at each position of 26.0 ° ± 0.3 °, 26.8 ° ± 0.3 °, 27.9 ° ± 0.1 °, and 28.2 ° ± 0.1 ° in line diffraction. It consists of what has a crystal structure.
不定比酸化チタンとしては、式ＴｉＯxで表されｘが１．７５以上２．００未満のものとしてマグネリ相が存在することが知られているが、本発明の化合物は異なる結晶構造を有している。また、電荷補償のため、３価のチタンが含有されている。ｘの値が１．８５以下では、本発明の結晶構造が保てず性能指数が低下する。また、たとえｘが１．８９以上２．００未満であってもマグネリ相では、熱伝導度が高くなり性能指数が低下する。 As the non-stoichiometric titanium oxide, it is known that a magnelite phase exists as a compound represented by the formula TiO x and x is 1.75 or more and less than 2.00. However, the compound of the present invention has a different crystal structure. ing. Further, trivalent titanium is contained for charge compensation. When the value of x is 1.85 or less, the crystal structure of the present invention cannot be maintained and the figure of merit is lowered. Moreover, even if x is 1.89 or more and less than 2.00, in the magnetic phase, the thermal conductivity increases and the figure of merit decreases.
本発明の熱電変換材料を構成する化合物の結晶構造の詳細は不明であるが、Ｘ線回折プロファイルでは、マグネリ相の結晶構造とは異なり、２θで２６．０°±０．３°、２６．８°±０．３°、２７．９°±０．１°、２８．２°±０．１°にピークを有する特定の結晶構造を有し、式ＴｉＯxで示され、ｘが１．８５以上２．００未満である化合物からなる熱電変換材料が、高い性能指数を有するのである。 Although the details of the crystal structure of the compound constituting the thermoelectric conversion material of the present invention are unknown, the X-ray diffraction profile differs from the crystal structure of the magnetic phase in 2θ at 26.0 ° ± 0.3 °, 26. It has a specific crystal structure with peaks at 8 ° ± 0.3 °, 27.9 ° ± 0.1 °, 28.2 ° ± 0.1 °, represented by the formula TiO x , where x is 1. The thermoelectric conversion material which consists of a compound which is 85 or more and less than 2.00 has a high figure of merit.
上記ｘの値は１．９２以上１．９３以下の範囲であるかまたは１．９６以上１．９８以下の範囲であると、性能指数が高くなる傾向があるので好ましく、この二つの領域のうちｘの値が１．９２以上１．９３以下の範囲がより好ましい。 The value of x is preferably in the range of 1.92 to 1.93 or in the range of 1.96 to 1.98 because the figure of merit tends to be high. The value of x is more preferably in the range of 1.92 to 1.93.
ここで、本発明の熱電変換材料にチタンと酸素以外の元素を性能指数向上剤として含有させて性能指数をさらに上げることも可能である。含有させることができる元素としては、アルカリ金属元素、アルカリ土類金属元素、希土類金属元素、４族金属元素、５族金属元素、６族金属元素、７族金属元素、１４族金属元素、１５族金属元素が挙げられる。アルカリ金属元素としては、具体的にはＬｉ、ＮａおよびＫが挙げられ、アルカリ土類金属元素としてはＭｇ、Ｃａ、ＳｒおよびＢａが挙げられ、希土類金属元素としてはＹ、ＬａおよびＣｅ挙げられ、４族金属元素としてはＺｒおよびＨｆが挙げられ、５族金属元素としてＶが挙げられ、６族金属元素としてはＣｒおよびＭｏが挙げられ、７族金属元素としてはＭｎが挙げられ、１４族金属元素としてはＳｎが挙げられ、１５族金属元素としてはＢｉが挙げられる。 Here, the thermoelectric conversion material of the present invention can contain an element other than titanium and oxygen as a performance index improver to further increase the performance index. Examples of elements that can be contained include alkali metal elements, alkaline earth metal elements, rare earth metal elements, group 4 metal elements, group 5 metal elements, group 6 metal elements, group 7 metal elements, group 14 metal elements, and group 15 A metal element is mentioned. Specific examples of the alkali metal element include Li, Na, and K. Examples of the alkaline earth metal element include Mg, Ca, Sr, and Ba. Examples of the rare earth metal element include Y, La, and Ce. Group 4 metal elements include Zr and Hf, Group 5 metal elements include V, Group 6 metal elements include Cr and Mo, Group 7 metal elements include Mn, Group 14 metal Examples of the element include Sn, and examples of the Group 15 metal element include Bi.
このうちアルカリ金属元素とアルカリ土類金属元素は、結晶構造のうちの酸素欠陥近傍の位置またはチタンと酸素の格子間に入って含有されることにより、熱伝導度を低下させて熱電変換材料の性能指数を向上させるものと考えられ、その含有量は前記Ｘ線回折により決めることができる結晶構造が保持できる範囲であればよく、通常は１重量ｐｐｍ以上５重量％以下の範囲である。希土類金属元素、４族金属元素はチタンのサイト（結晶格子における原子の位置）にチタンと置き換わって含有されることにより、熱伝導度を低下させて熱電変換材料の性能指数を向上させるものと考えられ、その含有量は前記Ｘ線回折により決めることができる結晶構造が保持できる範囲であればよく、通常は１重量ｐｐｍ以上５重量％以下の範囲である。また、５族金属元素、６族金属元素、７族金属元素、１２族金属元素、１３族金属元素は、３価のチタンを増大させて電気伝導度を上げることにより熱電変換材料の性能指数を向上させるものと考えられ、その含有量は前記Ｘ線回折により決めることができる結晶構造が保持できる範囲であればよく、通常は１重量ｐｐｍ以上５重量％以下の範囲である。 Among these, the alkali metal element and the alkaline earth metal element are contained in the vicinity of the oxygen defect in the crystal structure or between the lattices of titanium and oxygen, thereby reducing the thermal conductivity of the thermoelectric conversion material. It is considered that the figure of merit is improved, and the content thereof may be in a range that can maintain the crystal structure that can be determined by the X-ray diffraction, and is usually in the range of 1 ppm by weight to 5% by weight. It is considered that rare earth metal elements and group 4 metal elements are replaced by titanium at the titanium sites (atomic positions in the crystal lattice), thereby reducing the thermal conductivity and improving the performance index of thermoelectric conversion materials. The content thereof may be in a range that can maintain the crystal structure that can be determined by the X-ray diffraction, and is usually in the range of 1 ppm by weight to 5% by weight. In addition, Group 5 metal element, Group 6 metal element, Group 7 metal element, Group 12 metal element, Group 13 metal element increase performance index of thermoelectric conversion materials by increasing trivalent titanium and increasing electric conductivity. The content is considered to be improved as long as the crystal structure that can be determined by the X-ray diffraction can be maintained, and is usually in the range of 1 ppm by weight to 5% by weight.
熱電変換材料は、焼結体として用いるので、その密度も重要であり、実際の使用においては熱応力等の負荷が掛かるため、焼結体強度が必要であり、焼結体密度は１．９ｇ／ｃｍ3以上が好ましく、２．１ｇ／ｃｍ3以上がさらに好ましい。焼結体密度の上限は理論密度の４．２５ｇ／ｃｍ3である。 Since the thermoelectric conversion material is used as a sintered body, its density is also important. In actual use, a load such as thermal stress is applied, so the strength of the sintered body is necessary, and the sintered body density is 1.9 g. / Cm 3 or more is preferable, and 2.1 g / cm 3 or more is more preferable. The upper limit of the sintered body density is 4.25 g / cm 3 of the theoretical density.
焼結体強度には焼結体の粒径も影響を及ぼす。微粒である方が強度が高くなる傾向にあり、１０μｍ以下が好ましい。焼結体粒径の下限は通常は０．１μｍ程度である。 The particle size of the sintered body also affects the sintered body strength. Finer particles tend to have higher strength and are preferably 10 μm or less. The lower limit of the sintered body particle size is usually about 0.1 μm.
本発明の熱電変換材料は３価のＴｉを含有するため、酸化される可能性があるが、４００℃までは安定であり、この領域での熱電発電に適している。しかし、３価のチタンが長時間の使用により酸化され性能が低下するおそれがある場合やより高温で使用する場合は、熱電変換材料の表面を酸素が通過しない緻密な皮膜でコーティングしてもよい。皮膜材料としては具体的には、アルミナ、チタニア、ジルコニア、炭化珪素等が挙げられ。その皮膜により本発明の熱電変換材料をコーティング方法としては例えば、エアロゾルデポジション法、溶射法等が挙げられる。このコーティングにより酸化を防ぐことが可能であり、１０００℃まで使用することもできる。また、発電モジュールの構造を容器内に熱電変換素子を密閉し、容器内を真空とするかまたは容器内に窒素、アルゴン、ヘリウム等の不活性ガスを封入することもできる。 Since the thermoelectric conversion material of the present invention contains trivalent Ti, it may be oxidized, but is stable up to 400 ° C., and is suitable for thermoelectric power generation in this region. However, if the trivalent titanium is oxidized due to long-term use and the performance may be lowered or if it is used at a higher temperature, the surface of the thermoelectric conversion material may be coated with a dense film that does not allow oxygen to pass through. . Specific examples of the film material include alumina, titania, zirconia, and silicon carbide. Examples of a method for coating the thermoelectric conversion material of the present invention with the coating include an aerosol deposition method and a thermal spraying method. This coating can prevent oxidation and can be used up to 1000 ° C. In addition, the thermoelectric conversion element can be hermetically sealed in the container, and the container can be evacuated, or an inert gas such as nitrogen, argon, or helium can be sealed in the container.
次に本発明の製造方法について説明する。
本発明のｎ型熱電変換材料は、チタン化合物を水素含有雰囲気中で焼結して製造することができる。チタン化合物としては、焼成により酸化物となるものかまたは酸化チタンであればよく、例えば、酸化チタン、硫酸チタニル等が挙げられ、酸化チタン（チタニア）が好ましい。酸化チタンの結晶形はとしてはルチル、アナターゼ、ブルッカイトのいずれでもよい。
Next, the manufacturing method of this invention is demonstrated.
The n-type thermoelectric conversion material of the present invention can be produced by sintering a titanium compound in a hydrogen-containing atmosphere. The titanium compound may be any oxide or titanium oxide when fired, and examples thereof include titanium oxide and titanyl sulfate, and titanium oxide (titania) is preferable. The crystal form of titanium oxide may be any of rutile, anatase and brookite.
まず、これらのチタン化合物の粉末に圧力をかけて成形を行う。成形は工業的に通常行われている成形方法により行うことができる。例えば、１軸プレス、静水圧プレス（ＣＩＰ）、メカニカルプレス等により行うことができる。成形体は、角柱状、円柱状等の熱電変換素子として適切な形状となるように製造すればよい。 First, molding is performed by applying pressure to these titanium compound powders. Molding can be carried out by a molding method which is usually carried out industrially. For example, it can be performed by a uniaxial press, an isostatic press (CIP), a mechanical press or the like. What is necessary is just to manufacture a molded object so that it may become a shape suitable as thermoelectric conversion elements, such as prismatic shape and cylindrical shape.
次に、得られた成形体を焼結する。焼結は、３価のＴｉを焼結体中に存在させるため、還元性雰囲気中で行う必要がある。還元性雰囲気としては、水素を１体積％以上含有する不活性ガスからなる雰囲気が挙げられ、不活性ガスとしては窒素、アルゴン、ヘリウム等を用いることができる。 Next, the obtained molded body is sintered. Sintering needs to be performed in a reducing atmosphere because trivalent Ti is present in the sintered body. Examples of the reducing atmosphere include an atmosphere made of an inert gas containing 1% by volume or more of hydrogen. As the inert gas, nitrogen, argon, helium, or the like can be used.
本発明の熱電変換素子を製造するために適切な焼結条件は水素濃度により異なる。水素濃度が１体積％以上５％未満（残部は不活性雰囲気）の場合では、１０００℃以上１４００℃以下の温度範囲で１時間以上１０時間以下保持して焼結を行い、水素濃度が５体積％以上１００体積％以下（残部は不活性雰囲気）の場合では、９５０℃以上１０５０℃以下の温度範囲で１０分以上５時間以下保持して焼結を行う。 Suitable sintering conditions for producing the thermoelectric conversion element of the present invention depend on the hydrogen concentration. When the hydrogen concentration is 1% by volume or more and less than 5% (the remainder is an inert atmosphere), sintering is performed at a temperature range of 1000 ° C. or more and 1400 ° C. or less for 1 hour or more and 10 hours or less, and the hydrogen concentration is 5 volumes. % To 100% by volume (the balance is an inert atmosphere), sintering is performed at a temperature range of 950 ° C. to 1050 ° C. for 10 minutes to 5 hours.
焼結体の密度、粒径は熱電変換材料としての特性に影響するが、これらは、成形圧力、焼結温度により制御することができる。また、耐久性を向上させるため、製造した焼結体を空気中でアニ−ルしてもよい。 The density and particle size of the sintered body affect the properties of the thermoelectric conversion material, and these can be controlled by the molding pressure and the sintering temperature. In order to improve the durability, the manufactured sintered body may be annealed in the air.
また、熱伝導度を小さくするため、焼結体密度が１．９ｇ／ｃｍ3以上となる範囲で焼結体密度を低くし、多孔体からなる熱電変換材料とすることもできる。多孔体からなる熱電変換材料は、例えば、スプレードライ等により数十μｍの粒子に造粒し、得られた造粒粒子を成形する方法や、焼成粉末に樹脂ビーズやクルミ紛のような燃焼除去できる物質を混合し成形し、空気中で加熱して樹脂ビーズ等を燃焼除去して多孔体とし、さらに焼結して作製する方法等が挙げられる。 Further, in order to reduce the thermal conductivity, the sintered body density can be lowered within a range where the sintered body density is 1.9 g / cm 3 or more, and a thermoelectric conversion material comprising a porous body can be obtained. Thermoelectric conversion material made of porous material is granulated into particles of several tens of μm by, for example, spray drying, etc., and the resulting granulated particles are molded, or burned powder such as resin beads or walnut powder is removed by combustion Examples include a method of mixing and forming a material that can be produced, heating in air to burn and remove the resin beads to form a porous body, and further sintering.
焼結に用いるチタン化合物としては、チタン含有物質を成形せずに焼成し、得られた焼成粉末を用いることが好ましい。チタン含有物質としては、焼結用原料のチタン化合物と同様のものを用いることができる。 As a titanium compound used for sintering, it is preferable to use a fired powder obtained by firing without forming a titanium-containing material. As the titanium-containing substance, the same titanium compound as the raw material for sintering can be used.
焼成は、３価のＴｉをチタン化合物中に存在させるため、還元性雰囲気中で行う必要がある。還元性雰囲気としては、水素を１体積％以上含有する不活性ガスからなる雰囲気が挙げられ、不活性ガスとしては窒素、アルゴン、ヘリウム等を用いることができる。 Firing needs to be performed in a reducing atmosphere because trivalent Ti is present in the titanium compound. Examples of the reducing atmosphere include an atmosphere made of an inert gas containing 1% by volume or more of hydrogen. As the inert gas, nitrogen, argon, helium, or the like can be used.
本発明の熱電変換素子製造用の焼成粉末を製造するために適切な焼成条件は、還元性雰囲気中の水素ガス濃度により異なり、水素濃度１体積％以上５体積％未満（残部は不活性雰囲気）の場合では、１０００℃以上１４００℃以下の温度範囲で１時間以上１０時間以下保持して焼成を行い、水素濃度が５体積％以上１００体積％以下（残部は不活性雰囲気）の場合では、９５０℃以上１０５０℃以下の温度範囲で１０分以上５時間以下保持して焼成を行う。降温時も還元雰囲気中が好ましく、降温を不活性ガス中で行った場合は、還元が不充分になる傾向がある。 The firing conditions suitable for producing the fired powder for producing the thermoelectric conversion element of the present invention depend on the hydrogen gas concentration in the reducing atmosphere, and the hydrogen concentration is 1% by volume or more and less than 5% by volume (the remainder is an inert atmosphere). In the case of, firing is carried out in the temperature range of 1000 ° C. to 1400 ° C. for 1 hour to 10 hours, and in the case where the hydrogen concentration is 5% by volume to 100% by volume (the remainder is an inert atmosphere), 950 Firing is carried out by maintaining the temperature in the temperature range of 1050C to 1050C for 10 minutes to 5 hours. Even when the temperature is lowered, a reducing atmosphere is preferable. When the temperature is lowered in an inert gas, the reduction tends to be insufficient.
焼成により得られた焼成粉末は、成形する前に粉砕することが好ましく、焼成粉末を粉砕後に成形し焼結して熱電変換材料とする。この粉砕の程度により、焼結体密度を制御することもできる。粉砕は、ボールミル、振動ミル、アトライター、ダイノーミル等の通常工業的に用いられる装置により行うことができる。 The fired powder obtained by firing is preferably pulverized before molding, and the fired powder is shaped after grinding and sintered to obtain a thermoelectric conversion material. The density of the sintered body can be controlled by the degree of pulverization. The pulverization can be performed by a device that is usually used industrially, such as a ball mill, a vibration mill, an attritor, or a dyno mill.
こうして得られた熱電変換材料は、室温から５００℃の領域または表面処理により１０００℃まで使用することができ、性能指数が高く、しかも安価な酸化チタンが原料であり安価に製造することができるｎ型の熱電変換材料である。 The thermoelectric conversion material thus obtained can be used from room temperature to 500 ° C. or up to 1000 ° C. by surface treatment, and has a high figure of merit, and inexpensive titanium oxide is a raw material and can be manufactured at low cost. Type thermoelectric conversion material.
以下、本発明を実施例によりさらに詳しく説明するが、本発明はこれらによって限定されるものではない。
１．電気伝導度
焼結体を１０×３×３ｍｍの角柱に加工し、銀ペーストで白金線を装着し、直流４端子法で測定した。
２．ゼーベック係数
電気伝導度測定と同様の形状に加工した焼結体の両端にＲ熱電対および白金線をつけ、焼結体の温度および熱起電力を測定した。管状炉中で温度をコントロールし、温度差は、焼結体の片面に窒素ガスを接触させることにより制御した。温度差は１〜１０℃に制御した。
３．熱伝導度測定
真空理工株式会社製レーザーフラッシュ法熱伝導度測定装置ＴＣ−７０００型により測定した。
４．Ｘ線回折
粉末、焼結体の結晶構造は、株式会社リガク製Ｘ線回折測定装置ＲＩＮＴ２５００ＴＴＲ型によりＸ銭回折パターンを測定して分析した。
５．焼結体密度
焼結体の寸法および重量から見かけ密度を測定した。
６．酸素欠損量の測定
マックサイエンス社のＴＧ−ＤＴＡで１０℃／分でＴＧを測定、その重量増加量から酸素欠損量つまりｘを求めた。
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these.
1. Electrical conductivity The sintered body was processed into a square column of 10 × 3 × 3 mm, a platinum wire was attached with a silver paste, and measurement was performed by a direct current four-terminal method.
2. Seebeck coefficient An R thermocouple and a platinum wire were attached to both ends of the sintered body processed into the same shape as the electrical conductivity measurement, and the temperature and thermoelectromotive force of the sintered body were measured. The temperature was controlled in a tubular furnace, and the temperature difference was controlled by bringing nitrogen gas into contact with one side of the sintered body. The temperature difference was controlled at 1-10 ° C.
3. Measurement of thermal conductivity It was measured with a laser flash method thermal conductivity measuring device TC-7000 manufactured by Vacuum Riko Co., Ltd.
4). X-ray diffraction The crystal structure of the powder and the sintered body was analyzed by measuring an X-shaped diffraction pattern with an RINT2500TTR type X-ray diffraction measuring apparatus manufactured by Rigaku Corporation.
5. Sintered body density The apparent density was measured from the size and weight of the sintered body.
6). Measurement of oxygen deficiency TG was measured at 10 ° C./min with TG-DTA manufactured by Mac Science, and the oxygen deficiency, that is, x was determined from the weight increase.
実施例１
チタニア（石原テクノ株式会社製、ＰＴ４０１Ｍ（商品名））を１０ｇ秤量し１００％水素雰囲気中において１０００℃で１時間保持して焼成した。得られた焼成物は、Ｘ線回折により分析した結果、２６．２°、２６．９°、２７．９°、２８．２°にピークを持ち、マグネリ相とは異なるプロファイルを有していた。１５ｍｍφのジルコニアボールを用い粉砕し、得られた粉末を１ｔ／ｃｍ2の圧力の静水圧プレス成形によりペレット状に成形した。得られた成形体を、水素１００％の雰囲気において１０００℃で１時間で焼結した。得られた焼結体は、Ｘ線回折パターンを測定した結果、ルチルが数％混在していたが、２６．２°、２６．９°、２７．９°、２８．２°にピークを持ち、マグネリ相とは異なるプロファイルを有していた。焼結体密度は２．８ｇ／ｃｍ3で、焼結体粒径は約３μｍあった。ＴＧ−ＤＴＡで酸素量を測定した結果ＴｉＯ1.92であった。
Example 1
10 g of titania (manufactured by Ishihara Techno Co., Ltd., PT401M (trade name)) was weighed and held in a 100% hydrogen atmosphere at 1000 ° C. for 1 hour for firing. As a result of X-ray diffraction analysis, the obtained fired product had peaks at 26.2 °, 26.9 °, 27.9 °, and 28.2 °, and had a profile different from the magnetic phase. . The resulting powder was pulverized using 15 mmφ zirconia balls, and the obtained powder was formed into a pellet by hydrostatic press molding at a pressure of 1 t / cm 2 . The obtained molded body was sintered in an atmosphere of 100% hydrogen at 1000 ° C. for 1 hour. As a result of measuring the X-ray diffraction pattern, the obtained sintered body was mixed with several percent of rutile, but had peaks at 26.2 °, 26.9 °, 27.9 ° and 28.2 °. And had a profile different from that of the Magneli phase. The sintered compact density was 2.8 g / cm 3 and the sintered compact particle size was about 3 μm. The amount of oxygen measured by TG-DTA was TiO 1.92 .
該焼結体の特性は、３００Ｋで測定したゼーベック係数は１４４μＶ／Ｋ、電気伝導度は、３．４×１０3Ｓ／ｍ、熱伝導度（室温）は０．７Ｗ／ｍＫであり、性能指数を算出すると、０．１０×１０-3（１／Ｔ）であった。焼結体の強度は高く、加工等に問題はなかった。 The properties of the sintered body were as follows: the Seebeck coefficient measured at 300 K was 144 μV / K, the electrical conductivity was 3.4 × 10 3 S / m, and the thermal conductivity (room temperature) was 0.7 W / mK. The index was calculated to be 0.10 × 10 −3 (1 / T). The strength of the sintered body was high and there was no problem in processing.
実施例２
０．４μｍのチタニアを出発原料として用いた以外は実施例１と同様にして焼結体を得た。密度は２．１ｇ／ｃｍ3で、粒径は約２μｍであった。酸素量はＴｉＯ1.93であった。得られた焼結体は、Ｘ線回折パターンを測定した結果、２６．１°、２７．１°、２７．９°、２８．３°にピークを持ち、マグネリ相とは異なるプロファイルを有していた。該焼結体の特性は、室温（約２５℃）でのゼ−ベック係数は１２１μｍＶ／Ｋ、電気伝導度１．１×１０3ｓ／ｍ、熱伝導度は０．１Ｗ／ｍＫであり、性能指数を算出すると０．１６×１０-3であった。焼結体の強度は高く、加工等に問題はなかった。
Example 2
A sintered body was obtained in the same manner as in Example 1 except that 0.4 μm of titania was used as a starting material. The density was 2.1 g / cm 3 and the particle size was about 2 μm. The amount of oxygen was TiO 1.93 . As a result of measuring the X-ray diffraction pattern, the obtained sintered body had peaks at 26.1 °, 27.1 °, 27.9 °, and 28.3 °, and had a profile different from the magnetic phase. It was. The properties of the sintered body are as follows: the Seebeck coefficient at room temperature (about 25 ° C.) is 121 μmV / K, the electrical conductivity is 1.1 × 10 3 s / m, and the thermal conductivity is 0.1 W / mK. The figure of merit was calculated to be 0.16 × 10 −3 . The strength of the sintered body was high and there was no problem in processing.
実施例３
実施例１と同様の出発原料を用い、出発原料を焼成せずに１．０ｔ／ｃｍ2の圧力の静水圧プレス成形によりペレット状に成形し、得られた成形体を、３体積％Ｈ2含有窒素中で９７０℃で保持して焼結体を作製した。得られた焼結体は、Ｘ線回折により分析した結果、得られた焼成物は、Ｘ線回折パターンを測定した結果、２６．２°、２６．９°、２８．０°、２８．１°にピークを持ち、マグネリ相とは異なるプロファイルを有していた。焼結体密度は２．８ｇ／ｃｍ3で、焼結体粒径は０．５μｍであった。ＴＧ−ＤＴＡにより酸素量を測定した結果、組成はＴｉＯ1.96であった。
Example 3
The same starting material as in Example 1 was used, and the starting material was molded into a pellet by isostatic pressing at a pressure of 1.0 t / cm 2 without firing, and the resulting molded body was 3% by volume H 2. A sintered body was produced by holding at 970 ° C. in nitrogen-containing. The obtained sintered body was analyzed by X-ray diffraction. As a result of measuring the X-ray diffraction pattern of the obtained fired product, 26.2 °, 26.9 °, 28.0 °, 28.1 It had a peak at ° and had a profile different from the magnetic phase. The sintered compact density was 2.8 g / cm 3 and the sintered compact particle size was 0.5 μm. As a result of measuring the amount of oxygen by TG-DTA, the composition was TiO 1.96 .
該焼結体の特性は、３００Ｋでの測定でゼーベック係数は１３５μＶ／Ｋ、電気伝導度は、２．４×１０3Ｓ／ｍ、熱伝導度（室温）は０．６Ｗ／ｍＫであり、性能指数を算出すると、０．０７３×１０-3（１／Ｔ）であった。焼結体の強度は十分高く、加工等に問題はなかった。焼結体の強度は高く、加工等に問題はなかった。 The properties of the sintered body were measured at 300K, the Seebeck coefficient was 135 μV / K, the electrical conductivity was 2.4 × 10 3 S / m, and the thermal conductivity (room temperature) was 0.6 W / mK. The figure of merit was calculated to be 0.073 × 10 −3 (1 / T). The strength of the sintered body was sufficiently high and there was no problem in processing. The strength of the sintered body was high and there was no problem in processing.
比較例１
実施例１と同様の出発原料を用い、１．０ｔ／ｃｍ2の静水圧プレス成形によりペレット状に成形し、得られた成形体を、水素１００体積％中で１２００℃で保持して焼結した。得られた焼結体のＸ線回折パターンを測定した結果、該焼結体は主にＴｉ5Ｏ9（ＴｉＯxにおいてｘ＝１．８０）からなるマグネリ相であった。焼結体密度は３．８ｇ／ｃｍ3であり、室温（約２５℃）でのゼーベック係数は６７μＶ／Ｋ、電気伝導度は１．８×１０3Ｓ／ｍ、熱伝導度は６．３Ｗ／ｍＫであり、性能指数は、０．０１３×１０-3であった。
Comparative Example 1
Using the same starting materials as in Example 1, it was molded into a pellet by isostatic pressing at 1.0 t / cm 2 , and the resulting molded body was held at 1200 ° C. in 100 vol% hydrogen and sintered. did. As a result of measuring the X-ray diffraction pattern of the obtained sintered body, the sintered body was a magnetic phase mainly composed of Ti 5 O 9 (x = 1.80 in TiO x ). The density of the sintered body is 3.8 g / cm 3 , the Seebeck coefficient at room temperature (about 25 ° C.) is 67 μV / K, the electrical conductivity is 1.8 × 10 3 S / m, and the thermal conductivity is 6.3 W. / MK and the figure of merit was 0.013 × 10 −3 .
比較例２
実施例１と同様の出発原料を用い、焼結温度を９５０℃としたことと、成形圧力を０．５ｔ／ｃｍ2とした以外は実施例１と同様にして焼結体を作製した。得られた焼結体は、式ＴｉＯxにおいてｘ＝１．９４であり、焼結体密度は１．７ｇ／ｃｍ3であった。室温（約２５℃）でのゼーベック係数は４６μＶ／Ｋ、電気伝導度は０．６×１０3Ｓ／ｍ、熱伝導度は０．０９Ｗ／ｍＫであった。性能指数は０．０１４×１０-3であった。また、焼結体は強度がなく、容易に崩壊し加工することは不可能であった。
Comparative Example 2
A sintered body was produced in the same manner as in Example 1 except that the same starting materials as in Example 1 were used, the sintering temperature was 950 ° C., and the molding pressure was 0.5 t / cm 2 . The obtained sintered body was x = 1.94 in the formula TiO x , and the sintered body density was 1.7 g / cm 3 . The Seebeck coefficient at room temperature (about 25 ° C.) was 46 μV / K, the electric conductivity was 0.6 × 10 3 S / m, and the thermal conductivity was 0.09 W / mK. The figure of merit was 0.014 × 10 −3 . Further, the sintered body has no strength and cannot be easily collapsed and processed.
Claims (4)
As a titanium compound, when a titanium-containing substance has a hydrogen concentration of 1% by volume or more and less than 5%, it is fired by holding it at a temperature range of 1000 ° C. or more and 1400 ° C. or less for 1 hour or more and 10 hours or less, and a hydrogen concentration of 5% by volume or more and 100% The manufacturing method according to claim 3, wherein, in the case of% or less, firing is carried out by holding at a temperature range of 950 ° C. or more and 1050 ° C. or less for 10 minutes or more and 5 hours or less.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004286811A JP2006100683A (en) | 2004-09-30 | 2004-09-30 | Thermoelectric conversion material for titanium oxide |
| EP05767817A EP1791191A1 (en) | 2004-07-27 | 2005-07-22 | Thermoelectric conversion material and process for producing the same |
| US11/571,430 US20090205697A2 (en) | 2004-07-27 | 2005-07-22 | Thermoelectric conversion material and process for producing the same |
| KR1020077004296A KR20070048734A (en) | 2004-07-27 | 2005-07-22 | Thermoelectric conversion material and process for producing the same |
| PCT/JP2005/013897 WO2006011581A1 (en) | 2004-07-27 | 2005-07-22 | Thermoelectric conversion material and process for producing the same |
| TW094125080A TW200607762A (en) | 2004-07-27 | 2005-07-25 | Thermo-electric conversion material and its manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004286811A JP2006100683A (en) | 2004-09-30 | 2004-09-30 | Thermoelectric conversion material for titanium oxide |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2006100683A true JP2006100683A (en) | 2006-04-13 |
Family
ID=36240175
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2004286811A Withdrawn JP2006100683A (en) | 2004-07-27 | 2004-09-30 | Thermoelectric conversion material for titanium oxide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2006100683A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1876656A2 (en) * | 2006-07-03 | 2008-01-09 | National Institute of Advanced Industrial Science and Technology | Metal oxynitride material with a superior thermoelectric property |
| WO2008023650A1 (en) * | 2006-08-24 | 2008-02-28 | Sumitomo Chemical Company, Limited | Thermoelectric material, method for producing the same, and thermoelectric converter |
| JP2008135501A (en) * | 2006-11-28 | 2008-06-12 | Sumitomo Chemical Co Ltd | Thermoelectric conversion material |
| JP2008263056A (en) * | 2007-04-12 | 2008-10-30 | Sumitomo Chemical Co Ltd | Thermoelectric conversion material and method of manufacturing the same |
| WO2009014243A1 (en) * | 2007-07-26 | 2009-01-29 | Sumitomo Chemical Company, Limited | Thermoelectric conversion element and method for manufacturing the same |
| JP2010504903A (en) * | 2006-09-26 | 2010-02-18 | アトラノーヴァ・リミテッド | Process for producing substoichiometric titanium oxide by hydrogen reduction |
| JP2012199493A (en) * | 2011-03-23 | 2012-10-18 | Chiba Univ | Thermoelectric conversion material and production method therefor |
| JP2015162664A (en) * | 2014-02-28 | 2015-09-07 | 国立大学法人 千葉大学 | Thermoelectric conversion material and method for manufacturing the same |
-
2004
- 2004-09-30 JP JP2004286811A patent/JP2006100683A/en not_active Withdrawn
Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1876656A2 (en) * | 2006-07-03 | 2008-01-09 | National Institute of Advanced Industrial Science and Technology | Metal oxynitride material with a superior thermoelectric property |
| US7771626B2 (en) | 2006-07-03 | 2010-08-10 | National Institute Of Advanced Industrial Science And Technology | Metal oxynitride material with a superior thermoelectric property |
| EP1876656A3 (en) * | 2006-07-03 | 2010-08-04 | National Institute of Advanced Industrial Science and Technology | Metal oxynitride material with a superior thermoelectric property |
| WO2008023650A1 (en) * | 2006-08-24 | 2008-02-28 | Sumitomo Chemical Company, Limited | Thermoelectric material, method for producing the same, and thermoelectric converter |
| JP2008078608A (en) * | 2006-08-24 | 2008-04-03 | Sumitomo Chemical Co Ltd | Thermoelectric conversion material and method for producing the same |
| US8217256B2 (en) | 2006-08-24 | 2012-07-10 | Sumitomo Chemical Company, Limited | Thermoelectric material, method for producing the same, and thermoelectric converter |
| JP2010504903A (en) * | 2006-09-26 | 2010-02-18 | アトラノーヴァ・リミテッド | Process for producing substoichiometric titanium oxide by hydrogen reduction |
| JP2008135501A (en) * | 2006-11-28 | 2008-06-12 | Sumitomo Chemical Co Ltd | Thermoelectric conversion material |
| JP2008263056A (en) * | 2007-04-12 | 2008-10-30 | Sumitomo Chemical Co Ltd | Thermoelectric conversion material and method of manufacturing the same |
| WO2008133153A1 (en) * | 2007-04-12 | 2008-11-06 | Sumitomo Chemical Company, Limited | Thermoelectric conversion material, method for production thereof, and thermoelectric conversion element |
| EP2187460A1 (en) * | 2007-07-26 | 2010-05-19 | Sumitomo Chemical Company, Limited | Thermoelectric conversion element and method for manufacturing the same |
| JP2009032893A (en) * | 2007-07-26 | 2009-02-12 | Sumitomo Chemical Co Ltd | Thermoelectric conversion element and method for manufacturing the same |
| WO2009014243A1 (en) * | 2007-07-26 | 2009-01-29 | Sumitomo Chemical Company, Limited | Thermoelectric conversion element and method for manufacturing the same |
| EP2187460A4 (en) * | 2007-07-26 | 2012-01-18 | Sumitomo Chemical Co | Thermoelectric conversion element and method for manufacturing the same |
| JP2012199493A (en) * | 2011-03-23 | 2012-10-18 | Chiba Univ | Thermoelectric conversion material and production method therefor |
| JP2015162664A (en) * | 2014-02-28 | 2015-09-07 | 国立大学法人 千葉大学 | Thermoelectric conversion material and method for manufacturing the same |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2008124417A (en) | Thermoelectric conversion material, and its manufacturing method | |
| Mori et al. | Evaluation of Ni and Ti-doped Y2O3 stabilized ZrO2 cermet as an anode in high-temperature solid oxide fuel cells | |
| JP4867618B2 (en) | Thermoelectric conversion material | |
| JP4967772B2 (en) | Thermoelectric conversion material and method for producing the same | |
| KR20070048734A (en) | Thermoelectric conversion material and process for producing the same | |
| JP2008263056A (en) | Thermoelectric conversion material and method of manufacturing the same | |
| JP2007246294A (en) | Aluminum-containing zinc oxide sintered compact and method of manufacturing the same | |
| JP2009218541A (en) | Method for producing sintered body | |
| Kang et al. | Novel NTC ceramics based on pyrochlore-type A2Ti2O7 (A= Sm, Eu, Y) titanates for high-temperature thermistors | |
| JP2006100683A (en) | Thermoelectric conversion material for titanium oxide | |
| JP2009117449A (en) | OXIDE COMPOUND MATERIAL HAVING n-TYPE THERMOELECTRIC CHARACTERISTIC | |
| JP2006062951A (en) | Thermoelectric conversion material and its manufacturing method | |
| JP2009215149A (en) | Sintered body and thermoelectric conversion material | |
| JP4876721B2 (en) | Thermoelectric conversion material and method for producing the same | |
| JP2010161213A (en) | Thermoelectric conversion material, and method of manufacturing the same | |
| JP2011020902A (en) | Strontium titanate sintered compact and method for producing the same | |
| TW200950164A (en) | Sinter matter and thermoelectric conversion material | |
| JPH08231223A (en) | Thermoelectric conversing material | |
| KR101559942B1 (en) | Method of enhancing the thermoelectric properties and electrical conductivity in Ca-V oxide perovskite system by means of synthesizing the single phase | |
| JP2009196821A (en) | Perovskite-based oxide, its producing method and thermoelectric element using it | |
| JP2018078219A (en) | P-type thermoelectric semiconductor, manufacturing method therefor, and thermoelectric generation element using the same | |
| JP4844043B2 (en) | Thermoelectric conversion material and method for producing the same | |
| JP2007055878A (en) | Perovskite type oxide dense sintered compact and method of manufacturing the same | |
| JP3471890B2 (en) | Porous sintered body, heat-resistant electrode and solid oxide fuel cell | |
| Yasukawa et al. | Preparation of dense BaPbO3-based ceramics by a coprecipitation and their thermoelectric properties |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20070713 |
|
| RD05 | Notification of revocation of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7425 Effective date: 20080131 |
|
| RD05 | Notification of revocation of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7425 Effective date: 20080514 |
|
| A761 | Written withdrawal of application |
Free format text: JAPANESE INTERMEDIATE CODE: A761 Effective date: 20101115 |