WO2023171662A1 - CORPS FRITTÉ SEMI-CONDUCTEUR DE TYPE n, ÉLÉMENT ÉLECTRIQUE/ÉLECTRONIQUE, GÉNÉRATEUR THERMOÉLECTRIQUE ET PROCÉDÉ DE FABRICATION D'UN CORPS FRITTÉ SEMI-CONDUCTEUR DE TYPE n - Google Patents

CORPS FRITTÉ SEMI-CONDUCTEUR DE TYPE n, ÉLÉMENT ÉLECTRIQUE/ÉLECTRONIQUE, GÉNÉRATEUR THERMOÉLECTRIQUE ET PROCÉDÉ DE FABRICATION D'UN CORPS FRITTÉ SEMI-CONDUCTEUR DE TYPE n Download PDF

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WO2023171662A1
WO2023171662A1 PCT/JP2023/008556 JP2023008556W WO2023171662A1 WO 2023171662 A1 WO2023171662 A1 WO 2023171662A1 JP 2023008556 W JP2023008556 W JP 2023008556W WO 2023171662 A1 WO2023171662 A1 WO 2023171662A1
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sintered body
type semiconductor
semiconductor sintered
high manganese
manganese silicide
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PCT/JP2023/008556
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English (en)
Japanese (ja)
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直樹 貞頼
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日東電工株式会社
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/80—Constructional details
    • H10N10/85—Thermoelectric active materials
    • H10N10/851—Thermoelectric active materials comprising inorganic compositions

Definitions

  • the present invention relates to an n-type semiconductor sintered body, an electric/electronic member, a thermoelectric power generation device, and a method for manufacturing the n-type semiconductor sintered body.
  • thermoelectric materials Some semiconductors are known to have a large electromotive force per temperature difference (Seebeck coefficient), and such semiconductors are known to be useful as thermoelectric materials for thermoelectric power generation.
  • silicon-based alloy materials have attracted attention in recent years because of their low toxicity, availability at low cost, and easy control of electrical properties.
  • thermoelectric material In order for a thermoelectric material to have high thermoelectric performance, it is required that the material has high electrical conductivity and low thermal conductivity. Elemental silicon has a large Seebeck coefficient and high electrical conductivity, but its high thermal conductivity often results in poor thermoelectric performance. Therefore, various improvements have been made to silicon, and the use of silicon alloys made by adding other elements to silicon is also being considered. Among such silicon alloys, high manganese silicides (HMS) are expected to be put to practical use because they provide relatively high power generation performance, are low in toxicity, and are inexpensive. (For example, Patent Document 1, Non-Patent Document 1)
  • Non-Patent Document 3 When constructing a power generation device (power generation module) by combining a p-type semiconductor power generation material and an n-type semiconductor power generation material, it is necessary to combine different types of n-type power generation materials (base material types) with p-type high manganese silicide. Attempts have been made to use an n-type power generation material (different from the base material of the p-type power generation material), for example, an alloy such as magnesium silicide (for example, Non-Patent Document 2).
  • Miyazaki Jpn. J. Appl. Phys. , 2020, 59, SF0802. Aoyama et al, Jpn. J. Appl. Phys. , 2005, 44, pp. 4275-4281. Miyazaki et al, 2011, Jpn. J. Appl. Phys. 50,035804.
  • an object of the present invention to provide an n-type semiconductor material containing high manganese silicide and having excellent thermoelectric properties.
  • One form of the present invention includes a polycrystalline body containing high manganese silicide partially substituted with one or more elements other than Mn from Group 5 to Group 10, and has an electrical conductivity of 10,000 S/m or more. It is an n-type semiconductor sintered body.
  • an n-type semiconductor material containing high manganese silicide and having excellent thermoelectric properties it is possible to provide an n-type semiconductor material containing high manganese silicide and having excellent thermoelectric properties.
  • One embodiment of the present invention is an n-type semiconductor sintered material that includes a polycrystalline body containing high manganese silicide partially substituted with one or more elements other than Mn from Group 5 to Group 10, and exhibits high electrical conductivity. It is the body. According to this embodiment, an n-type high manganese silicide thermoelectric material exhibiting high thermoelectric performance can be obtained.
  • thermoelectric performance also referred to as thermoelectric conversion performance
  • thermoelectric conversion performance the dimensionless thermoelectric figure of merit ZT[-] is often used.
  • ZT is determined by the following formula.
  • thermoelectric conversion performance ZT ⁇ 2 ⁇ T/ ⁇ ...(1)
  • ⁇ [V/K] is the Seebeck coefficient
  • ⁇ [S/m] is the electrical conductivity (in the unit “S/m”, “S” is Siemens, “m” is meters)
  • ⁇ [ W/(mK)] represents thermal conductivity
  • T represents absolute temperature [K].
  • the Seebeck coefficient ⁇ refers to the potential difference generated per unit temperature difference.
  • the high manganese silicide described herein is one of them, and is represented by the formula MnSi ⁇ (where 1.6 ⁇ 2), and has a characteristic crystal structure, specifically a chimney ladder. It has a crystal structure called High manganese silicides are preferred as thermoelectric materials because they exhibit relatively low thermal conductivity due to their characteristic crystal structure. Further, it is known that the Seebeck coefficient ⁇ of a high manganese silicide-based material, that is, a high manganese silicide or an alloy material containing high manganese silicide is relatively high.
  • manganese silicide has less toxicity than materials such as Bi 2 Te 3 and PbTe, and can be obtained at low cost. Furthermore, compared to silicon materials and silicide materials (silicon germanium materials, etc.), high manganese silicide materials or materials containing alloys containing high manganese silicide have a higher power factor (the product of the square of the Seebeck coefficient and the electrical conductivity, ⁇ 2 ⁇ ) in (1) is also large. Therefore, by using a semiconductor sintered body containing high manganese silicide or based on high manganese silicide as in this embodiment, an environmentally friendly thermoelectric conversion element (thermoelectric generation element), and furthermore, a thermoelectric generation device can be produced at a low cost. It will be possible to provide.
  • thermoelectric generation element thermoelectric generation element
  • the n-type semiconductor sintered body according to this embodiment may be a sintered body of partially substituted high manganese silicide.
  • the partially substituted high manganese silicide mainly contains high manganese silicide or is based on high manganese silicide, and at least a part of the manganese in the manganese silicide is substituted with a predetermined element.
  • the n-type semiconductor sintered body according to this embodiment maintains the chimney ladder structure described above even in a partially substituted state.
  • the partially substituted high manganese silicide can be represented by the composition formula (Mn (1-x) A x )(Si (1-y) B y ) ⁇ .
  • A is an element that can be replaced with Mn in the manganese silicide, and may be one or more elements other than Mn from Groups 5 to 10. More specifically, A is one or more elements selected from the group consisting of V, Nb, Ta, Cr, Mo, W, Re, Fe, Ru, Os, Co, Rh, Ir, and Ni. It is preferable to have one.
  • A is more preferably an element shown on the right side of Mn in the periodic table, that is, one or more elements from Groups 8 to 10, since it can assist in converting the semiconductor sintered body to n-type. It is more preferable that it contains Co and/or Fe, or that it is Co and/or Fe. Further, it is more preferable for A to contain Fe, since the Seebeck coefficient can be increased, and the material is inexpensive and has high environmental safety.
  • the value of x in the above formula, that is, the ratio of Mn being substituted with A can be 0 or more, preferably 0.28 or more, and more preferably 0.32 or more. Furthermore, due to the limit of the amount of solid solution in high mangasilicide, x may be 0.42 or less.
  • silicon may not be substituted, but a portion of silicon may be substituted with another element. That is, in the above compositional formula, the value of y, which represents the proportion of silicon substituted with B, may be 0 or may exceed 0. Further, the value of y is preferably 0.2 or less. B is preferably one or more Group 14 elements, more preferably one or more elements selected from the group consisting of Ge and Sn. Further, as mentioned above, the atomic ratio ⁇ of Si to Mn in the high manganese silicide is 1.6 ⁇ 2, but even in the n-type semiconductor sintered body according to this embodiment, in other words, the partially substituted high manganese silicide Also, 1.6 ⁇ 2, preferably 1.7 ⁇ 1.8.
  • the n-type semiconductor sintered body according to this embodiment may be a high manganese silicide-based polycrystalline body, that is, a polycrystalline body containing high manganese silicide as a main crystal.
  • the main crystal refers to a crystal with the highest precipitation rate in an XRD pattern, etc., and preferably refers to a crystal that accounts for 55% by mass or more of the entire polycrystal.
  • the n-type semiconductor sintered body may contain manganese silicide (a different phase compound containing manganese and silicide) other than high manganese silicide, such as manganese monosilicide.
  • the n-type semiconductor sintered body according to this embodiment also includes an alloy (solid solution, eutectic, or intermetallic (including compounds) may be included.
  • the n-type semiconductor sintered body may contain unsubstituted high manganese silicide, or may contain a polycrystalline body containing an element other than manganese and silicide.
  • the polycrystalline body (semiconductor sintered body) according to this embodiment is produced by melting a compound containing raw material elements and/or a mixture thereof at a temperature higher than the melting point, and then cooling it, or by raising the temperature to a high enough temperature that it will not melt under pressure. It can be obtained by solid-phase diffusion reaction.
  • arc melting or high-frequency melting equipment can be used, while for the latter method, inert atmosphere furnaces, spark plasma sintering machines, hot press machines, hot isostatic pressing sintering (HIP) machines, etc. are suitable. It can be used for.
  • the electrical conductivity of the n-type semiconductor sintered body according to this embodiment may be 10,000 S/m or more at 27°C, preferably 15,000 S/m or more, more preferably 20,000 S/m or more, and even more preferably may be 25,000 S/m or more, more preferably 30,000 S/m or more.
  • thermoelectric performance can be improved.
  • the upper limit of the electrical conductivity of the semiconductor sintered body may be 1,000,000 S/m or less, and may be 500,000 S/m or less at 27°C.
  • thermoelectric figure of merit ZT of the semiconductor sintered body according to this embodiment can be, for example, 0.15 or more, 0.2 or more, 0.25 or more, or 0.3 or more at 527°C, preferably 0.4 or more, and It can be set to 1.5 or more.
  • the thermal conductivity of the n-type semiconductor sintered body according to this embodiment is preferably 8 W/m ⁇ K or less at 27°C, more preferably 5 W/m ⁇ K or less, and further preferably 4 W/m ⁇ K or less. Preferably, it may be 2 W/m ⁇ K or less.
  • the Seebeck coefficient of the semiconductor sintered body is preferably -300 to -50 ⁇ V/K at 27°C, more preferably -300 to -100 ⁇ V/K.
  • the average grain size of the crystal grains constituting the polycrystalline body is preferably 100 ⁇ m or less, more preferably 50 ⁇ m or less, and even more preferably 10 ⁇ m or less.
  • the grain size of the crystal grains is not particularly limited unless there are manufacturing restrictions. If there is no restriction, the thickness may be 1 nm or less, but it can be 1 nm or more.
  • the average grain size of crystal grains is measured by direct observation with a microscope such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM).
  • SEM scanning electron microscope
  • TEM transmission electron microscope
  • the semiconductor sintered body according to this embodiment may further contain an n-type dopant.
  • an n-type dopant By including an n-type dopant, the concentration of carriers (free electrons) can be increased and electrical conductivity can be improved, so thermoelectric performance can be improved.
  • the n-type dopant can be appropriately selected depending on the configuration and use of the thermoelectric material to be obtained. Preferably, the dopant is uniformly dispersed throughout the sintered body. As the n-type dopant, it is preferable to use one of phosphorus, arsenic, and antimony alone or in combination of two or more. Further, the n-type dopant is preferably diffused into the partially substituted high manganese silicide by diffusion doping, which will be described later.
  • the concentration of the n-type dopant in the sintered body is preferably 0.1 to 10 ⁇ 10 20 atoms/cm 3 , and 0.5 ⁇ The number of atoms may be 10 20 atoms/cm 3 or more, or 1 ⁇ 10 20 atoms/cm 3 or more.
  • Increasing the dopant concentration can improve the electrical conductivity, which improves the thermoelectric performance ZT, but if the dopant concentration becomes too large, the Seebeck coefficient decreases and the thermal conductivity increases, so the thermoelectric performance ZT decreases. Resulting in. However, by setting the dopant concentration within the above range, the thermoelectric performance ZT can be improved. Note that in this embodiment, the dopant concentration is equivalent to the carrier concentration calculated from the electrical characteristics.
  • the n-type semiconductor sintered body according to this embodiment can be used as an electric/electronic member (that is, an electric member and/or an electronic member), such as a power generation material or a thermoelectric element.
  • an electric/electronic member that is, an electric member and/or an electronic member
  • a power generation material or a thermoelectric element such as a power generation material or a thermoelectric element.
  • it is suitable for power generation devices that utilize waste heat, such as power generation devices installed in the engine and exhaust system of automobiles and ships, power generation devices installed in the heat radiation system of industrially used heating furnaces, etc. Can be used.
  • this embodiment includes the above-described n-type semiconductor sintered body as an n-type thermoelectric element, and a p-type semiconductor sintered body containing partially substituted or unsubstituted high manganese silicide as a p-type thermoelectric element. It may be a thermoelectric generator.
  • the element introduced in place of Mn is one or more elements other than Mn from Groups 5 to 10. It may be an element, preferably one or more elements from Group 5 and Group 6 elements.
  • the p-type semiconductor sintered body may be doped using diffusion doping, which will be described later. In that case, a dopant of an element other than the elements of Groups 5 to 10 may be used as the dopant.
  • silicon in the high manganese silicide in the p-type semiconductor sintered body may be replaced with another element.
  • thermoelectric power generation device the configuration of an n-type semiconductor sintered body used as an n-type thermoelectric element and a p-type semiconductor sintered body used as a p-type thermoelectric element (crystal grain size, high manganese silicide content, etc.) ) are preferably the same or close.
  • both the p-type and n-type elements can be constructed using high manganese silicide.
  • High manganese silicide is originally a p-type semiconductor.
  • One way to convert this unsubstituted high manganese silicide to n-type is to replace Mn partially but in a relatively large amount with an element shown on the right side of Mn in the periodic table. Thereby, carriers (free electrons) can be increased and an n-type semiconductor can be obtained.
  • partial substitution is performed by solid solution (melting and crystallization of Mn and the elements shown on the right side of Mn in the periodic table)
  • the amount of solid solution of the replaced element in high manganese silicide increases. has limitations and cannot introduce many elements.
  • the method for manufacturing a semiconductor sintered body according to the present embodiment includes high manganese silicide partially substituted with one or more elements other than Mn from Group 5 to Group 10, and has an average grain size of 100 ⁇ m or less.
  • the dopant element can be diffused from the coating to the particles, and the dopant element can be diffused more uniformly and at a high concentration.
  • the doping method according to the present method may be referred to as diffusion doping or thermal diffusion doping.
  • the mixture of raw material elements, the compound containing the raw material elements, or the mixture thereof is melted at a temperature higher than the melting point and then cooled, or the temperature is raised to a high enough temperature that it does not melt under pressure to form a solid phase. It involves obtaining a solid by a diffusion reaction.
  • arc melting or high-frequency melting equipment can be used, while for the latter method, inert atmosphere furnaces, spark plasma sintering machines, hot press machines, hot isostatic pressing sintering (HIP) machines, etc. are suitable. It can be used for.
  • the latter method is preferred in that a uniform composition can be obtained.
  • the particle preparation step further includes preparing particles (powder) by pulverizing the obtained solid by a known pulverization method. Further, particles (powder) may be synthesized from a raw material of an alloy containing manganese and silicon using a known crystal growth method such as chemical vapor deposition (CVD).
  • CVD chemical vapor deposition
  • the average particle size of the particles prepared in the particle preparation step may be 100 ⁇ m or less, preferably less than 50 ⁇ m, and more preferably 1 ⁇ m. Further, the D90 of the particles is preferably 100 ⁇ m or less, more preferably 50 ⁇ m or less, and even more preferably 10 ⁇ m or less.
  • the particle size of the particles before sintering within the above range, a sintered body having crystal grains with a particle size of 100 ⁇ m or less and being appropriately densified can be obtained.
  • the lower limit of the average particle size of the particles prepared in the particle preparation step is not limited, it is preferably 50 nm or more due to manufacturing constraints.
  • the average particle diameter of particles can be made into the volume-based median diameter measured by a laser diffraction type particle size distribution analyzer.
  • a film forming step is performed to form a film containing a dopant element on the surfaces of the particles obtained in the above particle preparation step.
  • This film forming step can be performed by dispersing the particles obtained in the particle preparation step in a solvent, adding a substance containing the above dopant element, and mixing the particles with a bead mill or the like. Thereafter, the solvent is removed by reduced pressure or the like, and the particles are dried, thereby obtaining particles having a coating film containing the dopant element formed on the surface.
  • the thickness of the coating may be between 0.5 and 5 nm.
  • the film can also be formed by a method in which organic molecules are diffused using a single gas constituting the atmosphere in which the particles exist, without using a solvent.
  • the dopant element contained in the coating is not particularly limited as long as it is an n-type dopant element.
  • the dopant element can be one or more of phosphorus, arsenic, and antimony.
  • the substance containing the dopant element may be a simple substance of the dopant element or may be a compound. Further, it may be a mixture of two or more types of simple substances, a mixture of two or more types of compounds, or a mixture of one or more types of simple substances and one or more types of compounds.
  • the substance containing the dopant element is a compound
  • the substance may be an organic compound or an inorganic compound. Moreover, it may be a polymer or a low molecule.
  • the organic compound may be a hydride, oxide, oxoacid, etc. containing a dopant element.
  • the substance when it is a mixture, it may be a mixture of an organic compound containing a dopant element and an organic compound not containing the dopant element, or a mixture of an inorganic compound containing the dopant element and an organic compound containing the dopant element.
  • the film formed in the film forming step is preferably a monomolecular film.
  • phosphoric acid alkylphosphonic acid, alkylphosphinic acid and its ester, polyvinylphosphonic acid, phosphine, trialkylphosphines such as triethylphosphine, tributylphosphine, etc.
  • arsenic arsine etc.
  • antimony antimony trioxide etc.
  • bismuth bismuth acid can be used.
  • the above substances may be used alone or in combination of two or more.
  • the substance containing the dopant element is preferably added in an amount of 3 to 80 parts by mass, preferably 10 to 60 parts by mass, relative to 100 parts by mass of the particles prepared in the particle preparation step. More preferred. By setting it within the above range, the electrical conductivity is increased and the thermal conductivity is suppressed, so that a semiconductor sintered body having high thermoelectric performance can be obtained.
  • the sintering step is not particularly limited as long as it is a method that can sinter the raw material particles (powder) described above, but includes spark plasma sintering (SPS), atmospheric pressure sintering (Two Examples include step sintering, hot pressing, hot isostatic pressing (HIP), and microwave sintering. Among these, it is preferable to use the discharge plasma sintering method, which can obtain smaller crystal grains.
  • the sintering temperature in the sintering step can be selected depending on the particle size of the particles and the composition of the partially substituted high manganese silicide, but is preferably 500°C or higher, more preferably 600°C or higher. Further, the sintering temperature is preferably 1100°C or lower, more preferably 1000°C or lower. By setting it within the above range, it is possible to promote the densification of the sintered body and maintain the average grain size of the crystal grains of the polycrystalline body at 100 ⁇ m or less.
  • the temperature increase rate in the sintering step is preferably 10 to 100°C/min, more preferably 20 to 60°C/min. By setting the temperature increase rate within the above range, it is possible to promote uniform sintering, suppress excessively rapid grain growth, and maintain the average grain size of the crystal grains of the polycrystalline body at 100 ⁇ m or less.
  • the pressurizing pressure is preferably 10 to 120 MPa, more preferably 20 to 100 MPa.
  • the doping element when particles with a film containing a dopant element formed on their surface are sintered (fired), the doping element is thermally diffused from the particle interface into the interior of the particle during sintering.
  • Such doping by thermal diffusion from the particle interface can improve the electrical conductivity of the obtained sintered body.
  • carriers can be doped at a higher concentration than doping that is performed without using thermal diffusion.
  • the semiconductor sintered body obtained by the method according to this embodiment has a higher concentration even when compared with a sintered body that has the same dopant concentration but is doped without utilizing thermal diffusion from the particle interface. Can exhibit high electrical conductivity.
  • particles containing high manganese silicide partially substituted with one or more elements other than Mn from Groups 5 to 10 are prepared, and a coating containing a dopant is formed on the surface of the particles.
  • This is an n-type semiconductor sintered body manufactured by forming an n-type semiconductor sintered body by sintering the particles with the coating formed on the surface thereof to obtain an n-type semiconductor sintered body.
  • the n-type semiconductor sintered body according to this embodiment maintains a chimney ladder structure of high manganese silicide and contains carriers (free electrons) at a higher concentration. Therefore, it has low thermal conductivity and high electrical conductivity. Therefore, it is possible to provide an n-type semiconductor sintered body having high thermoelectric performance ZT and using high manganese silicide as a base material.
  • a film containing a dopant element is formed on the surface of the particle in the film forming step, and the dopant element in the film is transferred from the particle surface into the inside of the particle by heat in the sintering step.
  • Doping is performed by diffusion.
  • the above-mentioned film forming step may be performed after the above-mentioned dopant element is previously contained in the particles at the stage of particle preparation step. For example, at the stage of melting an alloy material containing manganese, silicon, and one or more elements of groups 5 to 10 other than Mn, which are the main crystals, a substance containing a dopant element is mixed.
  • Particles (powder) containing the dopant can be prepared by cooling and pulverizing the melt.
  • a mixture of a powder of an alloy containing manganese, silicon, and one or more elements other than Mn from Groups 5 to 10 and a powder of a substance containing a dopant element is obtained, and the mixture is heated under pressure. It can be prepared by pulverizing a lump obtained by performing a solid-phase diffusion reaction at a high temperature that does not melt.
  • dopants such as phosphorus, arsenic, antimony, etc.
  • the dopants are incorporated into the particles in the particle preparation step, and the dopants are further thermally diffused from the coating in the coating formation and baking steps, thereby achieving a higher concentration. Doping becomes possible.
  • Example 1> (Preparation of high manganese silicide particles) 4.3 g of manganese (99.99% or higher purity), 5.6 g of silicon (99.99% or higher purity), and 2.3 g of iron (99.99% or higher purity) are placed in a graphite die/punch jig. The material was loaded, and was subjected to pressure and heat treatment under the conditions of 50 MPa and 800° C. for 10 minutes in an argon atmosphere using a discharge plasma sintering device, and then cooled. The obtained lump was crushed to 63 ⁇ m or less using a hammer crusher and a planetary ball mill. This was sieved to obtain high manganese silicide-iron alloy particles.
  • the obtained high manganese silicide-iron alloy particles were dispersed in heptane, and 0.4 g of polyvinylphosphonic acid (manufactured by Sigma-Aldrich, No. 661740) was added to 5.0 g of high manganese silicide-iron alloy particles. were put into the above planetary ball mill and mixed for 300 minutes. Thereafter, heptane was removed under reduced pressure, and the particles were further dried to obtain high manganese silicide-iron alloy particles (high manganese silicide particles partially substituted with Fe) coated with a monomolecular film.
  • polyvinylphosphonic acid manufactured by Sigma-Aldrich, No. 661740
  • the high manganese silicide-iron alloy particles coated with the monomolecular film are charged into a graphite die/punch jig, heated to 800°C using a discharge plasma sintering device, and a sintered body is formed. I got it. At this time, the pressurizing pressure was 40 MPa, and the heating rate was 50° C./min. The outer surface of the obtained sintered body was roughly polished to remove an impurity layer derived from graphite and the like. Further, it was cut using a dicing saw to obtain rectangular parallelepiped chips.
  • the density of the sintered body measured by the Archimedes method was 98.5% of that of the pure high manganese silicide-iron alloy.
  • Observation of the cross section of the sintered body using a transmission electron microscope (TEM) revealed that the average grain size of the crystal grains was 108 nm.
  • the electrical conductivity of the sintered body at 27° C. was 2.1 ⁇ 10 4 S/m, and the thermal conductivity was 3.0 W/m ⁇ K.
  • the carrier concentration was calculated based on the Seebeck coefficient (-115.5 ⁇ V/K) of the sintered body, it was found to be 0.65 in units of [10 20 atoms/cm 3 ].
  • the thermoelectric figure of merit ZT at 527°C was 0.23. Average grain size of crystal grains
  • Example 2 (Preparation of high manganese silicide particles) High manganese silicide-iron alloy particles were obtained in the same manner as in Example 1.
  • the high manganese silicide-iron alloy particles coated with the monomolecular film are charged into a graphite die/punch jig, heated to 800°C using a discharge plasma sintering device, and a sintered body is formed. I got it. At this time, the pressurizing pressure was 40 MPa, and the heating rate was 50° C./min. The outer surface of the obtained sintered body was roughly polished to remove an impurity layer derived from graphite and the like. Further, it was cut using a dicing saw to obtain rectangular parallelepiped chips.
  • the density of the sintered body measured by the Archimedes method was 98.2% of the pure high manganese silicide-iron alloy. Observation of the cross section of the sintered body using a transmission electron microscope (TEM) revealed that the average grain size of the crystal grains was 133 nm. Further, the electrical conductivity of the sintered body at 27° C. was 3.7 ⁇ 10 4 S/m, and the thermal conductivity was 3.3 W/m ⁇ K. When the carrier concentration was calculated based on the Seebeck coefficient (-95.5 ⁇ V/K) of the sintered body, it was found to be 1.08 in units of [10 20 atoms/cm 3 ]. Further, the thermoelectric figure of merit ZT at 527°C was 0.30.
  • Example 3 (Preparation of high manganese silicide particles) High manganese silicide-iron alloy particles were obtained in the same manner as in Example 1.
  • the obtained high manganese silicide-iron alloy particles were dispersed in heptane, and 2.0 g of polyvinylphosphonic acid (manufactured by Sigma-Aldrich, No. 661740) was added to 5.0 g of high manganese silicide-iron alloy particles. were put into the above planetary ball mill and mixed for 300 minutes. Thereafter, heptane was removed under reduced pressure, and the particles were further dried to obtain high manganese silicide-iron alloy particles (high manganese silicide particles partially substituted with Fe) coated with a monomolecular film.
  • the high manganese silicide-iron alloy particles coated with the monomolecular film are charged into a graphite die/punch jig, heated to 800°C using a discharge plasma sintering device, and a sintered body is formed. I got it. At this time, the pressurizing pressure was 40 MPa, and the heating rate was 50° C./min. The outer surface of the obtained sintered body was roughly polished to remove an impurity layer derived from graphite and the like. Further, it was cut using a dicing saw to obtain rectangular parallelepiped chips.
  • the density of the sintered body measured by the Archimedes method was 98.7% of that of the pure high manganese silicide-iron alloy.
  • Observation of the cross section of the sintered body using a transmission electron microscope (TEM) revealed that the average grain size of the crystal grains was 111 nm.
  • the electrical conductivity of the sintered body at 27° C. was 4.1 ⁇ 10 4 S/m, and the thermal conductivity was 3.5 W/m ⁇ K.
  • the carrier concentration was calculated based on the Seebeck coefficient (-79.4 ⁇ V/K) of the sintered body, it was found to be 1.22 in units of [10 20 atoms/cm 3 ].
  • the thermoelectric figure of merit ZT at 527°C was 0.32.
  • Example 4 (Preparation of high manganese silicide particles) Manganese (purity 99.99% or higher) 4.3g, silicon (purity 99.99% or higher) 5.6g, germanium (purity 99.99% or higher) 0.18g, and iron (purity 99.99% or higher) 2 .3 g was charged into a graphite die/punch jig, and subjected to pressure and heat treatment under argon atmosphere at 50 MPa and 800 °C for 10 minutes using a discharge plasma sintering device, and then cooled. did. The obtained lump was crushed to 63 ⁇ m or less using a hammer crusher and a planetary ball mill. This was sieved to obtain particles of high manganese silicide gelmide-iron alloy.
  • the obtained high manganese silicide gelmide-iron alloy particles were dispersed in heptane, and 1 g of polyvinylphosphonic acid (manufactured by Sigma-Aldrich, No. 661740) was added to 5.0 g of high manganese silicide-iron alloy particles.
  • the mixture was placed in the planetary ball mill described above and mixed for 300 minutes. Thereafter, heptane was removed under reduced pressure, and the mixture was further dried to obtain high manganese silicide gelmide-iron alloy particles (high manganese silicide gelmide particles partially substituted with Fe) coated with a monomolecular film.
  • the high manganese silicide gelmide-iron alloy particles coated with the monolayer film are charged into a graphite die/punch jig and heated to 800°C using a discharge plasma sintering device. A sintered body was obtained. At this time, the pressurizing pressure was 40 MPa, and the heating rate was 50° C./min. The outer surface of the obtained sintered body was roughly polished to remove an impurity layer derived from graphite and the like. Further, it was cut using a dicing saw to obtain rectangular parallelepiped chips.
  • the density of the sintered body measured by the Archimedes method was 97.8% of the pure high manganese silicide gelmide-iron alloy. Observation of the cross section of the sintered body using a transmission electron microscope (TEM) revealed that the average grain size of the crystal grains was 116 nm. Further, the electrical conductivity of the sintered body at 27° C. was 3.8 ⁇ 10 4 S/m, and the thermal conductivity was 3.2 W/m ⁇ K. When the carrier concentration was calculated based on the Seebeck coefficient (-83.1 ⁇ V/K) of the sintered body, it was found to be 1.22 in units of [10 20 atoms/cm 3 ]. Further, the thermoelectric figure of merit ZT at 527°C was 0.39.
  • the density of the sintered body measured by the Archimedes method was 98.5% of that of the pure high manganese silicide-iron alloy.
  • Observation of the cross section of the sintered body using a transmission electron microscope (TEM) revealed that the average grain size of the crystal grains was 124 nm.
  • the electrical conductivity of the sintered body at 27° C. was 0.79 ⁇ 10 4 S/m, and the thermal conductivity was 3.3 W/m ⁇ K.
  • the carrier concentration was calculated based on the Seebeck coefficient (-112.1 ⁇ V/K) of the sintered body, it was found to be 0.66 in units of [10 20 atoms/cm 3 ].
  • the thermoelectric figure of merit ZT at 527°C was 0.13.
  • a high manganese silicide-iron alloy (high manganese silicide partially substituted with Fe) or a high manganese germanium silicide-iron alloy (high manganese germanium silicide partially substituted with Fe) is diffused doped with phosphorus as a dopant element. It was found that the electrical conductivity of Examples 1 to 4 in which diffusion doping was performed was higher than that in Comparative Example 1 in which diffusion doping was not performed.

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  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Silicon Compounds (AREA)
  • Ceramic Products (AREA)

Abstract

L'invention concerne un corps fritté semi-conducteur de type n qui comprend un corps polycristallin contenant un siliciure de manganèse élevé partiellement substitué par au moins un élément autre que Mn parmi les éléments des groupes 5 à 10, et présente une conductivité électrique d'au moins 10 000 S/m.
PCT/JP2023/008556 2022-03-08 2023-03-07 CORPS FRITTÉ SEMI-CONDUCTEUR DE TYPE n, ÉLÉMENT ÉLECTRIQUE/ÉLECTRONIQUE, GÉNÉRATEUR THERMOÉLECTRIQUE ET PROCÉDÉ DE FABRICATION D'UN CORPS FRITTÉ SEMI-CONDUCTEUR DE TYPE n WO2023171662A1 (fr)

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JP2011210845A (ja) * 2010-03-29 2011-10-20 Ibaraki Univ ＧａあるいはＳｎでドーピングされたバルク状マンガンシリサイド単結晶体あるいは多結晶体およびその製造方法
WO2013011997A1 (fr) * 2011-07-19 2013-01-24 独立行政法人産業技術総合研究所 Module de conversion thermoélectrique empilé
JP2013183016A (ja) * 2012-03-01 2013-09-12 Tohoku Univ 熱電変換素子
JP2016164960A (ja) * 2015-02-27 2016-09-08 三菱化学株式会社 複合体及び該複合体を含む熱電変換素子
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JP2007042963A (ja) * 2005-08-05 2007-02-15 Toyota Central Res & Dev Lab Inc 熱電材料及びその製造方法
JP2011210845A (ja) * 2010-03-29 2011-10-20 Ibaraki Univ ＧａあるいはＳｎでドーピングされたバルク状マンガンシリサイド単結晶体あるいは多結晶体およびその製造方法
WO2013011997A1 (fr) * 2011-07-19 2013-01-24 独立行政法人産業技術総合研究所 Module de conversion thermoélectrique empilé
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JP2017084986A (ja) * 2015-10-29 2017-05-18 住友電気工業株式会社 熱電変換材料および熱電変換素子

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