WO2023176453A1 - Structure and method for manufacturing structure - Google Patents

Structure and method for manufacturing structure Download PDF

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Publication number
WO2023176453A1
WO2023176453A1 PCT/JP2023/007613 JP2023007613W WO2023176453A1 WO 2023176453 A1 WO2023176453 A1 WO 2023176453A1 JP 2023007613 W JP2023007613 W JP 2023007613W WO 2023176453 A1 WO2023176453 A1 WO 2023176453A1
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amorphous
aluminum
less
inorganic particles
znal
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PCT/JP2023/007613
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French (fr)
Japanese (ja)
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達郎 吉岡
夏希 佐藤
直樹 栗副
亮介 澤
徹 関野
知代 後藤
成訓 趙
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パナソニックＩｐマネジメント株式会社
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Publication of WO2023176453A1 publication Critical patent/WO2023176453A1/en

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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/44—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on aluminates

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  • the present invention relates to a structure and a method for manufacturing the structure.
  • a sintering method is known as a method for manufacturing structures made of ceramics.
  • the sintering method is a method of obtaining a sintered body by heating a powder made of an inorganic substance at a temperature lower than its melting point.
  • Patent Document 1 discloses a glass powder containing crystals that are made of WO 3 , TiO 2 or a solid solution thereof and has photocatalytic properties, and further, by sintering the glass powder, any desired It is disclosed that a solidified molded article having a shape can be obtained. It is also described that such a solidified molded product is useful as a photocatalytic functional material having excellent photocatalytic properties.
  • the sintering method requires heating the powder at a high temperature, there is a problem that energy consumption during production is large and costs are high.
  • the powder is simply compacted under low-temperature conditions, the powder particles will not bond together sufficiently, so the resulting molded product will have many pores and light will scatter, making it difficult to transmit light. may not occur.
  • An object of the present invention is to provide a structure that can be produced by a simple method, is dense, and has translucency.
  • a structure according to a first aspect of the present invention combines a ZnAl 2 O 4 crystal part and an adjacent crystal part, and combines a non-crystalline part containing an amorphous compound containing zinc and aluminum. It has a crystalline part.
  • the crystallite size of ZnAl 2 O 4 is 20 nm or less, the porosity is 20% or less, the total transmittance at a wavelength of 550 nm is 5% or more, and the amorphous portion does not substantially contain Si.
  • a method for producing a structure according to a second aspect of the present invention is to prepare a mixture containing a layered double hydroxide containing zinc and aluminum and a hydroxide containing aluminum at a pressure of 10 to 600 MPa, and , a step of pressurizing and heating at a temperature of 100 to 300°C.
  • the total transmittance of the structure at a wavelength of 550 nm is 5% or more, the structure includes an amorphous part containing an amorphous compound, and the amorphous part does not substantially contain Si.
  • FIG. 1 is a schematic diagram showing an example of a structure according to this embodiment.
  • FIG. 2 is a schematic diagram showing another example of the structure according to this embodiment.
  • FIG. 3 is a SEM image of the raw material powder used in the examples observed at 3000 times magnification.
  • FIG. 4 is a SEM image of the raw material powder used in the examples observed at 10,000 times magnification.
  • FIG. 5 is a graph showing the XRD pattern of the raw material powder used in the examples.
  • FIG. 6 is an infrared spectrum measured by the ATR method of the raw material powder used in the examples.
  • FIG. 7 is a graph showing the structure according to the example and the XRD pattern of ZnAl 2 O 4 registered in the ICSD.
  • FIG. 8 is an infrared spectrum measured by the ATR method of the raw material powder used in the example and the structure according to the example.
  • FIG. 9 is a graph showing the total transmittance of the structure according to the example.
  • FIG. 10 is a graph showing the in-line transmittance of the structure according to the example.
  • FIG. 11 is a SEM image of the structure according to the example magnified 10,000 times.
  • FIG. 12 is a SEM image of the structure according to the example magnified 30,000 times.
  • FIG. 13 is a SEM image of the structure according to the example magnified 200,000 times.
  • FIG. 14 is a SEM image of the structure according to the example magnified 1,000,000 times.
  • a structure 1 according to the present embodiment includes a crystalline portion 10 and an amorphous portion 20 of ZnAl 2 O 4 .
  • ZnAl 2 O 4 in the crystal part 10 is a zinc aluminum composite oxide.
  • ZnAl 2 O 4 is also known as the chemical structure of gahnite, which is classified into the spinel group.
  • the crystal system of ZnAl 2 O 4 is classified as a cubic system. Cubic crystal compounds are suitable for optical applications because they have small anisotropy in refractive index due to crystal planes and low internal scattering. Furthermore, ZnAl 2 O 4 has low absorption of light in the visible light region, and is therefore particularly suitable for optical applications.
  • the crystallite size of ZnAl 2 O 4 is 20 nm or less. When the crystallite size is 20 nm or less, light passing through the structure 1 is less likely to be scattered, and the light transmittance in the structure 1 can be increased.
  • the crystallite size may be 10 nm or less, 5 nm or less, or 4 nm or less.
  • the crystallite size is determined by measuring the full width at half maximum (FWHM) of the largest peak derived from ZnAl 2 O 4 in the range of 2 ⁇ from 33° to 38° using powder X-ray diffraction (XRD) method. It can be obtained by calculating using Scherrer's equation. It is assumed that the spread of the diffraction line is a model expressed by a Gaussian function, and the Scherrer constant K is set to 0.94.
  • the amorphous portion 20 connects adjacent crystal portions 10. By bonding adjacent crystal parts 10 via the amorphous part 20, the crystal parts 10 are three-dimensionally bonded to each other, so that a bulk body with high mechanical strength can be obtained.
  • the amorphous portion 20 may be in direct contact with the crystal portion 10. Further, the amorphous portion 20 may cover at least a portion of the surface of each of the plurality of crystal portions 10. The amorphous portion 20 may cover the entire surface of each of the plurality of crystal portions 10. As a result, the crystalline portion 10 and the amorphous portion 20 are firmly bonded to each other, so that it is possible to obtain the structure 1 with further excellent compactness and mechanical strength.
  • the plurality of crystalline parts 10 may have portions to which each of the plurality of crystalline parts 10 is directly bonded without intervening the amorphous part 20.
  • the amorphous portion 20 contains an amorphous compound containing zinc and aluminum.
  • the amorphous compound may be a hydroxide containing zinc and aluminum.
  • the amorphous portion 20 may contain an amorphous compound other than the amorphous compound containing zinc and aluminum.
  • the amorphous portion 20 may contain as a main component an amorphous compound containing zinc and aluminum.
  • the main component means that the amorphous portion 20 contains the amorphous compound in a total molar ratio of 50% or more.
  • the amorphous compound may contain 60% or more, 70% or more, 80% or more, or 90% or more of the amorphous part 20 in terms of molar ratio. You can stay there.
  • the amorphous portion 20 does not substantially contain Si.
  • the amorphous part 20 does not substantially contain Si means that the amorphous part 20 is not intentionally made to contain Si. Therefore, when Si is mixed into the amorphous portion 20 as an unavoidable impurity, the condition that “the amorphous portion 20 substantially does not contain Si” is satisfied.
  • substantially not containing a predetermined element means that the amorphous portion 20 may contain 1% by mass or less of a compound having the predetermined element.
  • the amorphous portion 20 or the amorphous compound preferably does not substantially contain alkali metal elements, B, V, Te, P, Bi, and Pb.
  • the amorphous part 20 or the amorphous compound as unavoidable impurities, "the amorphous part 20 or the amorphous compound The condition of ⁇ substantially free of alkali metal elements, B, V, Te, P, Bi, and Pb'' is satisfied.
  • the amorphous portion 20 or the amorphous compound preferably does not substantially contain Ca, Sr, and Ba.
  • the amorphous part 20 or the amorphous compound does not substantially contain Ca, Sr, and Ba
  • the amorphous part 20 or the amorphous compound is intentionally added to Ca, Sr, and Ba. This means that it does not contain Ba. Therefore, if Ca, Sr, and Ba are mixed into the amorphous portion 20 or the amorphous compound as unavoidable impurities, “the amorphous portion 20 or the amorphous compound substantially contains Ca, Sr, and Ba. satisfies the condition "No.”
  • the structure 1 may include a crystalline portion 10 and an amorphous portion 20 as main components.
  • the term "main component” means that the structure 1 includes crystalline portions 10 and amorphous portions 20 in a total volume ratio of 50% or more.
  • the crystalline portion 10 and the amorphous portion 20 may contain a total volume ratio of 60% or more, 70% or more, 80% or more, or 90% or more of the structure 1 by volume. % or more.
  • the crystalline portion 10 and the amorphous portion 20 may have a total molar ratio of 50% or more, 60% or more, 70% or more, and 80% or more of the structure 1. % or more, or 90% or more.
  • the structure 1 may include a plurality of inorganic particles 30 having an average particle diameter of 100 nm or more.
  • the inorganic particles 30 function as an aggregate, so that the strength of the structure 1 can be increased.
  • the average particle diameter of the inorganic particles 30 may be 1 ⁇ m or more, 5 ⁇ m or more, or 10 ⁇ m or more.
  • the average particle diameter of the plurality of inorganic particles 30 may be 50 ⁇ m or less, or may be 30 ⁇ m or less.
  • average particle diameter refers to a field of view of several to several tens of fields using an observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM). The value calculated as the average value of the particle diameter of the particles observed in the sample is adopted.
  • the shape of the inorganic particles 30 is not particularly limited, but may be, for example, spherical. Further, the inorganic particles 30 may be whisker-like (acicular) particles or scale-like particles. Since whisker-like particles or scale-like particles have higher contactability with other particles than spherical particles, it is possible to increase the strength of the entire structure 1.
  • the refractive index of the inorganic particles 30 may be less than or equal to the refractive index of ZnAl 2 O 4 or may be smaller than the refractive index of ZnAl 2 O 4 . Thereby, diffuse reflection of light within the structure 1 can be suppressed. Further, the refractive index of the inorganic particles 30 may be less than or equal to the refractive index of an amorphous compound containing zinc and aluminum that is included in the amorphous portion 20, or may be smaller than the refractive index of the amorphous compound. good. Thereby, diffuse reflection of light within the structure 1 can be suppressed. Therefore, it is possible to provide a structure 1 with high translucency.
  • the inorganic particles 30 are composed of an inorganic substance, and the inorganic substance may contain at least one metal element selected from the group consisting of alkali metals, alkaline earth metals, transition metals, base metals, and metalloids.
  • alkaline earth metals include beryllium and magnesium in addition to calcium, strontium, barium and radium.
  • Transition metals include, for example, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, yttrium, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, silver, tungsten, platinum, and gold.
  • Base metals include aluminum, zinc, gallium, cadmium, indium, tin, mercury, thallium, lead, bismuth and polonium.
  • Metalloids include boron, silicon, germanium, arsenic, antimony and tellurium.
  • the inorganic substance constituting the inorganic particles 30 is, for example, at least one selected from the group consisting of oxides, nitrides, hydroxides, hydroxide oxides, sulfides, borides, carbides, and halides of the above metal elements. It may be.
  • the inorganic substance constituting the inorganic particles 30 may be an oxide of the above metal element.
  • the inorganic substance constituting the inorganic particles 30 may be a simple metal oxide or a composite metal oxide. A simple metal oxide contains one kind of metal element, and a complex metal oxide contains two or more kinds of metal elements.
  • the inorganic substance contained in the inorganic particles 30 may be a crystalline compound or an amorphous compound.
  • the inorganic particles 30 may contain ZnAl 2 O 4 . Since the inorganic particles 30 contain the same ZnAl 2 O 4 as the crystal part 10, the strength of the structure 1 can be increased while maintaining translucency.
  • the inorganic particles 30 may contain an oxide of the above metal element as a main component.
  • the inorganic particles 30 may contain 80 mol% or more of the above metal element oxide, may contain 90 mol% or more, or may contain 95 mol% or more.
  • the volume ratio of the plurality of inorganic particles 30 may be 30% or more. In this case, the obtained structure 1 becomes a structure 1 in which the characteristics of the inorganic particles 30 can be easily utilized. Further, in the structure 1, the volume ratio of the plurality of inorganic particles 30 may be 40% or more, or may be 50% or more. The volume ratio of the inorganic particles 30 may be larger than the volume ratio of the amorphous portion 20.
  • the structure 1 may contain organic matter and resin particles. As will be described later, since the structure 1 can be obtained by applying pressure while heating to 100 to 300° C., a member with low heat resistance can be added to the structure 1. Furthermore, the structure 1 is not limited to a member having low heat resistance such as an organic substance, and may include particles containing an inorganic compound other than the crystal part 10, the amorphous part 20, and the inorganic particles 30.
  • the inorganic substance contained in the structure 1 preferably does not contain a hydrate of a calcium compound.
  • the calcium compounds mentioned here include tricalcium silicate (alite, 3CaO ⁇ SiO 2 ), dicalcium silicate (belite, 2CaO ⁇ SiO 2 ), calcium aluminate (3CaO ⁇ Al 2 O 3 ), and calcium aluminoferrite. (4CaO.Al 2 O 3.Fe 2 O 3 ) and calcium sulfate (CaSO 4.2H 2 O). Since the inorganic substance contained in the structure 1 does not contain a hydrate of the above-mentioned calcium compound, the porosity in the cross section of the structure 1 is reduced, so that the mechanical strength can be increased.
  • the inorganic substance does not contain a hydrate of the calcium compound. Further, it is preferable that the inorganic substance contained in the structure 1 does not include phosphate cement, zinc phosphate cement, or calcium phosphate cement. Since the inorganic substance does not contain these cements, the porosity in the cross section of the structure 1 is reduced, so that the mechanical strength can be increased.
  • the porosity in the cross section of the structure 1 is 20% or less. That is, when observing the cross section of the structure 1, the average value of the ratio of pores per unit area is 20% or less. When the porosity is 20% or less, the structure 1 becomes dense and its strength increases. Therefore, it becomes possible to improve the machinability of the structure 1. Further, when the porosity is 20% or less, cracks are suppressed from occurring in the structure 1 starting from the pores, so that the bending strength of the structure 1 can be increased.
  • the porosity in the cross section of the structure 1 is preferably 10% or less, more preferably 8% or less, even more preferably 5% or less, and particularly preferably 1% or less. The smaller the porosity in the cross section of the structure 1, the more suppressed are cracks originating from the pores, making it possible to increase the strength of the structure 1.
  • porosity can be determined as follows. First, a cross section of the structure 1 is observed to distinguish between pores and non-pores. Then, the unit area and the area of pores in the unit area are measured, the ratio of pores per unit area is determined, and this value is defined as the porosity. It is more preferable to determine the pore ratio per unit area at a plurality of locations in the cross section of the structure 1, and then use the average value of the pore ratio per unit area as the porosity. When observing the cross section of the structure 1, an optical microscope, a scanning electron microscope (SEM), or a transmission electron microscope (TEM) can be used. Further, the unit area and the area of pores within the unit area may be measured by binarizing an image observed with a microscope.
  • SEM scanning electron microscope
  • TEM transmission electron microscope
  • the size of the pores existing inside the structure 1 is not particularly limited, but is preferably as small as possible. Since the size of the pores is small, cracks originating from the pores are suppressed, so that the strength of the structure 1 can be increased and the machinability of the structure 1 can be improved. Note that the size of the pores in the structure 1 is preferably 5 ⁇ m or less, more preferably 1 ⁇ m or less, and even more preferably 100 nm or less. Similar to the porosity described above, the size of the pores existing inside the structure 1 can be determined by observing the cross section of the structure 1 with a microscope.
  • the total transmittance of the structure 1 at a wavelength of 550 nm is 5% or more.
  • the total transmittance may be 10% or more, 20% or more, or 30% or more.
  • the total transmittance can be measured according to the regulations of JIS B7081.
  • the shape of the structure 1 is not particularly limited, and may be, for example, plate-like, film-like, rectangular, block-like, rod-like, or spherical. Further, when the structure 1 is plate-shaped or film-shaped, the thickness thereof is not particularly limited, but may be, for example, 50 ⁇ m or more.
  • the structure 1 of this embodiment is formed by a pressure heating method, as will be described later. Therefore, a thick structure 1 can be easily obtained. Note that the thickness of the structure 1 can also be set to 500 ⁇ m or more, 1 mm or more, or 1 cm or more.
  • the upper limit of the thickness of the structure 1 is not particularly limited, but may be, for example, 50 cm.
  • the structure 1 combines a ZnAl 2 O 4 crystal part 10 and an adjacent crystal part 10, and forms an amorphous part containing an amorphous compound containing zinc and aluminum. It is equipped with 20.
  • the crystallite size of ZnAl 2 O 4 is 20 nm or less, the porosity is 20% or less, the total transmittance at a wavelength of 550 nm is 5% or more, and the amorphous portion 20 does not substantially contain Si.
  • such a structure 1 can be manufactured by a simple method, and is dense and translucent.
  • the structure 1 can be formed into a thick plate shape, and is also dense and has excellent chemical stability. Further, the structure 1 has high mechanical strength, can be cut like a general ceramic member, and can also be surface-treated. Therefore, the structure 1 can be suitably used as an optical member.
  • the optical member is not particularly limited, examples thereof include window materials, filters, lenses, and the like.
  • the method for manufacturing the structure 1 includes the steps of pressurizing and heating a mixture containing a layered double hydroxide and a hydroxide containing aluminum. Thereby, a dense structure 1 can be obtained.
  • the layered double hydroxide contained in the mixture may be in the form of particles.
  • the average particle diameter of the layered double hydroxide particles may be less than 100 nm.
  • the hydroxide contained in the mixture may be in the form of particles.
  • the average particle diameter of the hydroxide particles may be less than 100 nm.
  • the layered double hydroxide contains zinc and aluminum.
  • both metal ions are mixed at the atomic level. Therefore, by using such a layered double hydroxide as a raw material, it is possible to shorten the elemental diffusion distance during the reaction, compared to the case where, for example, zinc hydroxide and aluminum hydroxide are used as raw materials. Therefore, ZnAl 2 O 4 can be easily formed even under low temperature conditions.
  • the layered double hydroxide has a Zn source and an Al source uniformly mixed at the atomic level, it is possible to suppress the generation of impurities such as ZnO and AlOOH by heating and pressurization.
  • Layered double hydroxide is a compound represented by the composition formula [M 2+ 1-x M 3+ x (OH) 2 ][A m- ] x/m ⁇ nH 2 O (here, M 2+ is Mg 2+ , Zn 2+ , Co 2+ , Ni 2+ and Cu 2+ , M 3+ is a trivalent metal such as Al 3+ , Ga 3+ , Cr 3+ , Fe 3+ and Mn 3+ , A m- is CO 3 2- , NO 3 - and Cl - , and x is 1/4 to 1/3).
  • Layered double hydroxide is also called LDH, and forms a layered structure in which double hydroxide layers represented by [M 2+ 1-x M 3+ x (OH) 2 ] are stacked.
  • the layered double hydroxide has a layer of double hydroxide represented by [M 2+ 1-x M 3+ x (OH) 2 ], between which there is a layer of [ A m- ]
  • a sandwich structure with an intervening intermediate layer is stacked to form a laminate structure.
  • the double hydroxide layer may form a two-dimensional sheet in which metal ions are located at the center of an octahedron and share edges.
  • M 2+ in the Mg(OH) 2 (Brucite) type octahedral layer is replaced with M 3+ and is positively charged.
  • the positive charge of the double hydroxide layer is counteracted by the layer containing hydrated anions.
  • the layered double hydroxide may be a compound represented by the composition formula [Zn 2+ 1-x Al 3+ x (OH) 2 ][CO 3 2- ] x/2 ⁇ nH 2 O. More specifically, x may be 1/3. That is, the layered double hydroxide may be a compound represented by the composition formula [Zn 2+ 2/3 Al 3+ 1/3 (OH) 2 ][CO 3 2- ] 1/6 ⁇ nH 2 O. .
  • the layered double hydroxide may be crystalline.
  • the hydroxide contained in the mixture contains aluminum.
  • the hydroxide may specifically be aluminum hydroxide (Al(OH) 3 ).
  • the hydroxide containing aluminum may be amorphous.
  • the method for preparing the mixture is not particularly limited, and the mixture can be prepared by any known method.
  • a mixture containing a layered double hydroxide and a hydroxide containing aluminum may be prepared by a reverse coprecipitation method.
  • a mixture containing a layered double hydroxide and a hydroxide containing aluminum can be produced by dropping a mixed solution containing zinc ions and aluminum ions into an alkaline solution.
  • zinc ions and aluminum ions can be mixed at the ion level, so ZnAl 2 O 4 can be produced at a low heating temperature.
  • a mixed solution containing zinc ions and aluminum ions can be obtained by dissolving zinc salts and aluminum salts in a solvent.
  • zinc salts include zinc chloride.
  • aluminum salts include aluminum chloride.
  • the solvent include water.
  • the molar ratio of aluminum ions to zinc ions contained in the mixed solution is, for example, 1.5 or more and 2.5 or more.
  • the molar ratio may be 1.8 or more, or 1.9 or more. Further, the molar ratio may be 2.3 or less, or 2.1 or less.
  • the total metal ion concentration of zinc and aluminum in the mixed solution may be 200 mmol/L or more and 800 mmol/L or less.
  • the metal ion concentration may be 300 mmol/L or more, or 400 mmol/L or more.
  • the metal ion concentration may be 700 mmol/L or less, or 600 mmol/L or less.
  • the zinc ion concentration contained in the mixed solution may be 70 mmol/L or more and 260 mmol/L or less.
  • the zinc ion concentration may be 100 mmol/L or more, or 130 mmol/L or more.
  • the zinc ion concentration may be 230 mmol/L or less, or 200 mmol/L or less.
  • the aluminum ion concentration contained in the mixed solution may be 140 mmol/L or more and 520 mmol/L or less.
  • the aluminum ion concentration may be 200 mmol/L or more, or 260 mmol/L or more.
  • the aluminum ion concentration may be 460 mmol/L or less, or 400 mmol/L or less.
  • the alkaline solution may be, for example, an aqueous sodium carbonate (Na 2 CO 3 ) solution.
  • the concentration of the sodium carbonate aqueous solution may be, for example, 800 mmol/L or more and 1200 mmol/L or less.
  • the pH of the alkaline solution may be 7 or more and 10.5 or less.
  • the pH of the alkaline solution may be adjusted with an aqueous sodium hydroxide solution or the like.
  • the mixture may further contain a plurality of inorganic particles having an average particle diameter of 100 nm or more.
  • the same inorganic particles as the inorganic particles 30 described above can be used as the inorganic particles.
  • the average particle diameter, shape, refractive index, material, characteristics, etc. of the inorganic particles contained in the mixture can be the same as those of the inorganic particles 30 described above.
  • the mixture containing the layered double hydroxide and the hydroxide containing aluminum is pressurized and heated.
  • the mixture may also include water, such as pure water or ion-exchanged water.
  • the mixture may be filled inside a mold, pressurized and heated. After filling the mold with the mixture, the mold may be heated if necessary. By applying pressure to the mixture inside the mold, a high pressure state is created inside the mold.
  • the structure 1 can then be obtained by taking out the pressurized and heated mixture from inside the mold.
  • the conditions for pressurizing and heating the mixture are not particularly limited as long as the reaction between the layered double hydroxide and the hydroxide containing aluminum proceeds.
  • the temperature at which the mixture is heated is preferably 100 to 250°C, and even more preferably 100 to 200°C.
  • the pressure when pressurizing the above mixture is more preferably 50 to 600 MPa, and even more preferably 200 to 600 MPa.
  • the pressurizing time is preferably 1 minute to 360 minutes, more preferably 10 minutes to 240 minutes.
  • the structure 1 having a dense structure can be obtained by the reaction under pressure and heating as described above. Further, as a method of forming an aggregate of inorganic particles, a method of pressing only the powder of inorganic particles to form a green compact and then sintering the compact at a high temperature (for example, 1700° C. or higher) is also considered. However, even if the green compact of inorganic particles is sintered at a high temperature, the resulting structure 1 will have many pores and will have insufficient mechanical strength. Furthermore, when inorganic particles are sintered at high temperatures, precise temperature control is required, which increases manufacturing costs.
  • a high temperature for example, 1700° C. or higher
  • the manufacturing method of the present embodiment the mixture containing the layered double hydroxide and the hydroxide containing aluminum is heated and pressurized, so that the structure 1 is dense and has excellent strength. Obtainable. Furthermore, since the manufacturing method of this embodiment can be obtained by applying pressure while heating at 100° C. to 300° C., precise temperature control is not required and manufacturing costs can be reduced.
  • the method for manufacturing the structure 1 of the present embodiment is to produce a mixture containing a layered double hydroxide containing zinc and aluminum and a hydroxide containing aluminum at a pressure of 10 to 600 MPa, and , a step of pressurizing and heating at a temperature of 100 to 300°C.
  • the total transmittance of the structure 1 at a wavelength of 550 nm is 5% or more, the structure 1 includes an amorphous portion 20 containing an amorphous compound, and the amorphous portion 20 does not substantially contain Si. Therefore, according to the manufacturing method of this embodiment, the dense and translucent structure 1 can be manufactured using a simple method.
  • a raw material powder was synthesized by a reverse coprecipitation method. Specifically, first, 16.7 mmol of zinc chloride (ZnCl 2 ) and 33.3 mmol of aluminum chloride hexahydrate (AlCl 3 .6H 2 O) were dissolved in water to prepare 100 mL of a mixed aqueous solution. . Further, 50 mmol of sodium carbonate (Na 2 CO 3 ) was dissolved in water to prepare 50 mL of an aqueous sodium carbonate solution. The mixed aqueous solution was added dropwise to the sodium carbonate aqueous solution while adjusting the pH to about 10 with a 5 mol/L aqueous sodium hydroxide solution. The resulting suspension was stirred at room temperature for 24 hours, then filtered, and the residue was washed four times with 150 mL of water. The washed residue was dried at 70° C. for 8 hours to obtain a raw material powder.
  • ZnCl 2 zinc chloride
  • FIG. 3 is a SEM image of the obtained raw material powder observed at 3000x magnification.
  • FIG. 4 is a SEM image of the obtained raw material powder observed at a magnification of 10,000 times. As shown in FIGS. 3 and 4, it was confirmed that the particle diameters in the raw material powder were irregular and micron-sized.
  • FIG. 5 is a graph showing the XRD pattern of the obtained raw material powder. As shown in Figure 5, the XRD pattern of the powder includes the peaks of [Zn 2+ 2/3 Al 3+ 1/3 (OH) 2 ][CO 3 2- ] 1/6 ⁇ 2/3H 2 O. This was confirmed.
  • FIG. 6 shows an infrared spectrum of the obtained raw material powder measured by the ATR method. As shown in FIG. 6, it was confirmed that the infrared spectrum had absorption peaks derived from hydroxyl groups (-OH), water (H 2 O), and carbonate ions (CO 3 2- ).
  • a structure was produced by heating and pressurizing 0.3 g of the raw material powder obtained as described above at a pressure of 400 MPa and a temperature of 180° C. for 3 hours.
  • FIG. 8 shows an infrared spectrum of the obtained structure measured by the ATR method.
  • the infrared spectrum confirmed that the absorption peaks derived from hydroxyl groups (-OH), water (H 2 O), and carbonate ions (CO 3 2- ) were smaller than those of the raw material powder. .
  • the peak derived from water (H 2 O) in the layered double hydroxide had almost disappeared.
  • FIG. 9 is a graph showing the total transmittance of the structure according to the example.
  • FIG. 10 is a graph showing the in-line transmittance of the structure according to the example. As shown in FIG. 9, the total transmittance of the structure according to the example was 36% at a wavelength of 550 nm. Further, the in-line transmittance of the structure according to the example was 0.24% at a wavelength of 550 nm.
  • Cross-section polisher processing was performed on the cross section of the structure according to the example obtained as described above. Then, the cross section of the structure was observed using a scanning electron microscope (SEM). SEM images of the structure according to the example magnified 10,000 times, 30,000 times, 200,000 times, and 1,000,000 times are shown in FIGS. 11 to 14, respectively. Further, the SEM image in FIG. 12 was binarized, the area ratio of the pores was calculated from the binarized image, and the average value was taken as the porosity. As a result, it was found that the porosity of the structure according to the example was 0.8%. Since the porosity of the structure is low, it is thought that cracks originating from the pores are suppressed from occurring in the structure.
  • SEM scanning electron microscope
  • the density of the structure of the example was measured, the density was 2.86 g/cm 3 , which is the relative density of the structure based on the density of ZnAl 2 O 4 (4.5 g/cm 3 ). was 63.5%.
  • the porosity is 0.8%, which is essentially 0%, and that no peaks other than ZnAl 2 O 4 can be observed in FIG. 7, it can be seen that the structure contains an amorphous compound. From the infrared spectrum in FIG. 8 and the results of thermal analysis (not shown), it is estimated that the amorphous compound is a hydroxide containing zinc and aluminum. This hydroxide is presumed to be a part of the layered double hydroxide that has dehydrated and become amorphous.

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Abstract

This structure (1) comprises: crystal parts (10) of ZnAl2O4; and an amorphous part (20) which bonds the adjacent crystal parts (10) and contains an amorphous compound having zinc and aluminum. The crystallite size of ZnAl2O4 is at most 20 nm, the porosity is at most 20%, the total transmittance at a wavelength of 550 nm is at least 5%, and the amorphous part (20) does not substantially contain Si.

Description

構造体及び構造体の製造方法Structure and method for manufacturing the structure
　本発明は、構造体及び構造体の製造方法に関する。 The present invention relates to a structure and a method for manufacturing the structure.
　セラミックスからなる構造体の製造方法として、焼結法が知られている。焼結法は、無機物質からなる粉末を融点よりも低い温度で加熱することにより、焼結体を得る方法である。 A sintering method is known as a method for manufacturing structures made of ceramics. The sintering method is a method of obtaining a sintered body by heating a powder made of an inorganic substance at a temperature lower than its melting point.
　特許文献１では、ＷＯ３、ＴｉＯ２又はこれらの固溶体からなり、光触媒特性を有する結晶を含有したガラス粉粒体が開示されており、さらに当該ガラス粉粒体を焼結することにより、任意の形状を有する固化成形物が得られることが開示されている。そして、このような固化成形物は、優れた光触媒特性を有する光触媒機能性素材として有用であることが記載されている。 Patent Document 1 discloses a glass powder containing crystals that are made of WO 3 , TiO 2 or a solid solution thereof and has photocatalytic properties, and further, by sintering the glass powder, any desired It is disclosed that a solidified molded article having a shape can be obtained. It is also described that such a solidified molded product is useful as a photocatalytic functional material having excellent photocatalytic properties.
特開２０１１－４６６０２号公報Japanese Patent Application Publication No. 2011-46602
　しかしながら、焼結法は、粉末を高温で加熱する必要があることから、製造時のエネルギー消費が大きく、コストが掛かるという問題がある。また、低温条件下で粉末のみを単に圧粉しただけでは、粉末の粒子同士が十分に結合しないことから、得られる成形体には多くの気孔が存在し、光が散乱するため、透光性が発現しないおそれがある。 However, since the sintering method requires heating the powder at a high temperature, there is a problem that energy consumption during production is large and costs are high. In addition, if the powder is simply compacted under low-temperature conditions, the powder particles will not bond together sufficiently, so the resulting molded product will have many pores and light will scatter, making it difficult to transmit light. may not occur.
　本発明は、このような従来技術の有する課題に鑑みてなされたものである。そして、本発明の目的は、簡易な方法で作製することが可能であり、緻密で透光性を有する構造体を提供することにある。 The present invention has been made in view of the problems of the prior art. An object of the present invention is to provide a structure that can be produced by a simple method, is dense, and has translucency.
　上記課題を解決するために、本発明の第一の態様に係る構造体は、ＺｎＡｌ２Ｏ４の結晶部と、隣接する結晶部を結合し、亜鉛及びアルミニウムを有する非晶質化合物を含む非晶質部と、を備えている。ＺｎＡｌ２Ｏ４の結晶子サイズは２０ｎｍ以下であり、気孔率は２０％以下であり、波長５５０ｎｍにおける全透過率は５％以上であり、非晶質部はＳｉを実質的に含まない。 In order to solve the above problems, a structure according to a first aspect of the present invention combines a ZnAl 2 O 4 crystal part and an adjacent crystal part, and combines a non-crystalline part containing an amorphous compound containing zinc and aluminum. It has a crystalline part. The crystallite size of ZnAl 2 O 4 is 20 nm or less, the porosity is 20% or less, the total transmittance at a wavelength of 550 nm is 5% or more, and the amorphous portion does not substantially contain Si.
　本発明の第二の態様に係る構造体の製造方法は、亜鉛とアルミニウムとを含む層状複水酸化物と、アルミニウムを含む水酸化物とを含む混合物を、圧力が１０～６００ＭＰａであり、かつ、温度が１００～３００℃である条件下で加圧及び加熱する工程を含む。波長５５０ｎｍにおける構造体の全透過率は５％以上であり、構造体は非晶質化合物を含む非晶質部を備え、非晶質部はＳｉを実質的に含まない。 A method for producing a structure according to a second aspect of the present invention is to prepare a mixture containing a layered double hydroxide containing zinc and aluminum and a hydroxide containing aluminum at a pressure of 10 to 600 MPa, and , a step of pressurizing and heating at a temperature of 100 to 300°C. The total transmittance of the structure at a wavelength of 550 nm is 5% or more, the structure includes an amorphous part containing an amorphous compound, and the amorphous part does not substantially contain Si.
図１は、本実施形態に係る構造体の一例を示す模式図である。FIG. 1 is a schematic diagram showing an example of a structure according to this embodiment. 図２は、本実施形態に係る構造体の別の例を示す模式図である。FIG. 2 is a schematic diagram showing another example of the structure according to this embodiment. 図３は、実施例で用いた原料粉末を３０００倍で観察したＳＥＭ像である。FIG. 3 is a SEM image of the raw material powder used in the examples observed at 3000 times magnification. 図４は、実施例で用いた原料粉末を１００００倍で観察したＳＥＭ像である。FIG. 4 is a SEM image of the raw material powder used in the examples observed at 10,000 times magnification. 図５は、実施例で用いた原料粉末のＸＲＤパターンを示すグラフである。FIG. 5 is a graph showing the XRD pattern of the raw material powder used in the examples. 図６は、実施例で用いた原料粉末をＡＴＲ法によって測定した赤外線スペクトルである。FIG. 6 is an infrared spectrum measured by the ATR method of the raw material powder used in the examples. 図７は、実施例に係る構造体及びＩＣＳＤに登録されたＺｎＡｌ２Ｏ４のＸＲＤパターンを示すグラフである。FIG. 7 is a graph showing the structure according to the example and the XRD pattern of ZnAl 2 O 4 registered in the ICSD. 図８は、実施例で用いた原料粉末と実施例に係る構造体とをＡＴＲ法によって測定した赤外線スペクトルである。FIG. 8 is an infrared spectrum measured by the ATR method of the raw material powder used in the example and the structure according to the example. 図９は、実施例に係る構造体の全透過率を示すグラフである。FIG. 9 is a graph showing the total transmittance of the structure according to the example. 図１０は、実施例に係る構造体の直線透過率を示すグラフである。FIG. 10 is a graph showing the in-line transmittance of the structure according to the example. 図１１は、実施例に係る構造体を１００００倍に拡大したＳＥＭ像である。FIG. 11 is a SEM image of the structure according to the example magnified 10,000 times. 図１２は、実施例に係る構造体を３００００倍に拡大したＳＥＭ像である。FIG. 12 is a SEM image of the structure according to the example magnified 30,000 times. 図１３は、実施例に係る構造体を２０００００倍に拡大したＳＥＭ像である。FIG. 13 is a SEM image of the structure according to the example magnified 200,000 times. 図１４は、実施例に係る構造体を１００００００倍に拡大したＳＥＭ像である。FIG. 14 is a SEM image of the structure according to the example magnified 1,000,000 times.
　以下、図面を用いて本実施形態に係る構造体及び構造体の製造方法について詳細に説明する。なお、図面の寸法比率は説明の都合上誇張されており、実際の比率と異なる場合がある。 Hereinafter, a structure and a method for manufacturing the structure according to the present embodiment will be described in detail using the drawings. Note that the dimensional ratios in the drawings are exaggerated for convenience of explanation and may differ from the actual ratios.
　＜構造体＞
　図１に示すように、本実施形態に係る構造体１は、ＺｎＡｌ２Ｏ４の結晶部１０と、非晶質部２０とを備えている。 <Structure>
As shown in FIG. 1, a structure 1 according to the present embodiment includes a crystalline portion 10 and an amorphous portion 20 of ZnAl 2 O 4 .
　結晶部１０のＺｎＡｌ２Ｏ４は、亜鉛アルミニウム複合酸化物である。ＺｎＡｌ２Ｏ４は、スピネルグループに分類されるガーナイトの化学構造としても知られている。ＺｎＡｌ２Ｏ４の結晶系は立方晶系に分類されている。立方晶系の化合物は、結晶面による屈折率の異方性が小さく、内部散乱が小さいことから、光学用途に適している。また、ＺｎＡｌ２Ｏ４は、可視光領域の光の吸収が少ないため、光学用途に特に適している。 ZnAl 2 O 4 in the crystal part 10 is a zinc aluminum composite oxide. ZnAl 2 O 4 is also known as the chemical structure of gahnite, which is classified into the spinel group. The crystal system of ZnAl 2 O 4 is classified as a cubic system. Cubic crystal compounds are suitable for optical applications because they have small anisotropy in refractive index due to crystal planes and low internal scattering. Furthermore, ZnAl 2 O 4 has low absorption of light in the visible light region, and is therefore particularly suitable for optical applications.
　ＺｎＡｌ２Ｏ４の結晶子サイズは２０ｎｍ以下である。結晶子サイズが２０ｎｍ以下であることにより、構造体１を通過する光が散乱しにくく、構造体１における光の透過率を高くすることができる。結晶子サイズは、１０ｎｍ以下であってもよく、５ｎｍ以下であってもよく、４ｎｍ以下であってもよい。本明細書において、結晶子サイズは、粉末Ｘ線回折（ＸＲＤ）法により、２θが３３°～３８°の範囲内において、ＺｎＡｌ２Ｏ４に由来する最も大きいピークの半値全幅（ＦＷＨＭ）を測定し、シェラーの式を用いて算出することによって得ることができる。なお、回折線の広がりはガウス関数で表されるモデルであると仮定し、シェラー定数Ｋ＝０．９４としている。 The crystallite size of ZnAl 2 O 4 is 20 nm or less. When the crystallite size is 20 nm or less, light passing through the structure 1 is less likely to be scattered, and the light transmittance in the structure 1 can be increased. The crystallite size may be 10 nm or less, 5 nm or less, or 4 nm or less. In this specification, the crystallite size is determined by measuring the full width at half maximum (FWHM) of the largest peak derived from ZnAl 2 O 4 in the range of 2θ from 33° to 38° using powder X-ray diffraction (XRD) method. It can be obtained by calculating using Scherrer's equation. It is assumed that the spread of the diffraction line is a model expressed by a Gaussian function, and the Scherrer constant K is set to 0.94.
　非晶質部２０は、隣接する結晶部１０を結合している。隣接する結晶部１０が非晶質部２０を介して結合することにより、結晶部１０同士が三次元的に結合するため、機械的強度の高いバルク体を得ることができる。非晶質部２０は、結晶部１０と直接接触していてもよい。また、非晶質部２０は、複数の結晶部１０の各々の表面の少なくとも一部を覆っていてもよい。非晶質部２０は、複数の結晶部１０の各々の表面全体を覆っていてもよい。これにより、結晶部１０と非晶質部２０とが強固に結合することから、緻密性及び機械的強度にさらに優れた構造体１を得ることができる。複数の結晶部１０は非晶質部２０を介さず、複数の結晶部１０の各々が直接結合する部分を有していてもよい。 The amorphous portion 20 connects adjacent crystal portions 10. By bonding adjacent crystal parts 10 via the amorphous part 20, the crystal parts 10 are three-dimensionally bonded to each other, so that a bulk body with high mechanical strength can be obtained. The amorphous portion 20 may be in direct contact with the crystal portion 10. Further, the amorphous portion 20 may cover at least a portion of the surface of each of the plurality of crystal portions 10. The amorphous portion 20 may cover the entire surface of each of the plurality of crystal portions 10. As a result, the crystalline portion 10 and the amorphous portion 20 are firmly bonded to each other, so that it is possible to obtain the structure 1 with further excellent compactness and mechanical strength. The plurality of crystalline parts 10 may have portions to which each of the plurality of crystalline parts 10 is directly bonded without intervening the amorphous part 20.
　非晶質部２０は、亜鉛及びアルミニウムを有する非晶質化合物を含んでいる。非晶質化合物は、亜鉛及びアルミニウムを有する水酸化物であってもよい。非晶質部２０は、亜鉛及びアルミニウムを有する非晶質化合物以外の非晶質化合物を含んでいてもよい。 The amorphous portion 20 contains an amorphous compound containing zinc and aluminum. The amorphous compound may be a hydroxide containing zinc and aluminum. The amorphous portion 20 may contain an amorphous compound other than the amorphous compound containing zinc and aluminum.
　非晶質部２０は、亜鉛及びアルミニウムを有する非晶質化合物を主成分として含んでいてもよい。ここで、主成分とは、非晶質部２０のうち、上記非晶質化合物をモル比で合計５０％以上含むことを意味する。上記非晶質化合物は、非晶質部２０に対し、モル比で６０％以上含んでいてもよく、７０％以上含んでいてもよく、８０％以上含んでいてもよく、９０％以上含んでいてもよい。 The amorphous portion 20 may contain as a main component an amorphous compound containing zinc and aluminum. Here, the main component means that the amorphous portion 20 contains the amorphous compound in a total molar ratio of 50% or more. The amorphous compound may contain 60% or more, 70% or more, 80% or more, or 90% or more of the amorphous part 20 in terms of molar ratio. You can stay there.
　非晶質部２０は、Ｓｉを実質的に含まない。本明細書において、「非晶質部２０は、Ｓｉを実質的に含まない」とは、非晶質部２０に故意にＳｉを含有させたものではないことを意味する。そのため、非晶質部２０にＳｉが不可避不純物として混入した場合は、「非晶質部２０は、Ｓｉを実質的に含まない」という条件を満たす。本明細書において、所定の元素を実質的に含まないとは、所定の元素を有する化合物が非晶質部２０に１質量％以下含まれていてもよいことを意味する。 The amorphous portion 20 does not substantially contain Si. In this specification, "the amorphous part 20 does not substantially contain Si" means that the amorphous part 20 is not intentionally made to contain Si. Therefore, when Si is mixed into the amorphous portion 20 as an unavoidable impurity, the condition that “the amorphous portion 20 substantially does not contain Si” is satisfied. In this specification, "substantially not containing a predetermined element" means that the amorphous portion 20 may contain 1% by mass or less of a compound having the predetermined element.
　非晶質部２０又は非晶質化合物は、アルカリ金属元素、Ｂ、Ｖ、Ｔｅ、Ｐ、Ｂｉ及びＰｂを実質的に含まないことが好ましい。本明細書において、「非晶質部２０又は非晶質化合物は、アルカリ金属元素、Ｂ、Ｖ、Ｔｅ、Ｐ、Ｂｉ及びＰｂを実質的に含まない」とは、非晶質部２０又は非晶質化合物に故意にアルカリ金属元素、Ｂ、Ｖ、Ｔｅ、Ｐ、Ｂｉ及びＰｂを含有させたものではないことを意味する。そのため、非晶質部２０又は非晶質化合物にアルカリ金属元素、Ｂ、Ｖ、Ｔｅ、Ｐ、Ｂｉ及びＰｂが不可避不純物として混入した場合は、「非晶質部２０又は非晶質化合物は、アルカリ金属元素、Ｂ、Ｖ、Ｔｅ、Ｐ、Ｂｉ及びＰｂを実質的に含まない」という条件を満たす。 The amorphous portion 20 or the amorphous compound preferably does not substantially contain alkali metal elements, B, V, Te, P, Bi, and Pb. In this specification, "the amorphous part 20 or the amorphous compound does not substantially contain an alkali metal element, B, V, Te, P, Bi, and Pb" means that the amorphous part 20 or the amorphous compound This means that the crystalline compound is not intentionally made to contain alkali metal elements, B, V, Te, P, Bi, and Pb. Therefore, if alkali metal elements, B, V, Te, P, Bi, and Pb are mixed into the amorphous part 20 or the amorphous compound as unavoidable impurities, "the amorphous part 20 or the amorphous compound The condition of ``substantially free of alkali metal elements, B, V, Te, P, Bi, and Pb'' is satisfied.
　非晶質部２０又は非晶質化合物は、Ｃａ、Ｓｒ及びＢａを実質的に含まないことが好ましい。本明細書において、「非晶質部２０又は非晶質化合物は、Ｃａ、Ｓｒ及びＢａを実質的に含まない」とは、非晶質部２０又は非晶質化合物に故意にＣａ、Ｓｒ及びＢａを含有させたものではないことを意味する。そのため、非晶質部２０又は非晶質化合物にＣａ、Ｓｒ及びＢａが不可避不純物として混入した場合は、「非晶質部２０又は非晶質化合物は、Ｃａ、Ｓｒ及びＢａを実質的に含まない」という条件を満たす。 The amorphous portion 20 or the amorphous compound preferably does not substantially contain Ca, Sr, and Ba. In this specification, "the amorphous part 20 or the amorphous compound does not substantially contain Ca, Sr, and Ba" means that the amorphous part 20 or the amorphous compound is intentionally added to Ca, Sr, and Ba. This means that it does not contain Ba. Therefore, if Ca, Sr, and Ba are mixed into the amorphous portion 20 or the amorphous compound as unavoidable impurities, “the amorphous portion 20 or the amorphous compound substantially contains Ca, Sr, and Ba. satisfies the condition "No."
　構造体１は、結晶部１０と非晶質部２０とを、主成分として備えていてもよい。ここで、主成分とは、構造体１のうち、結晶部１０と非晶質部２０とを体積比で合計５０％以上含むことを意味する。結晶部１０と非晶質部２０とは、構造体１に対し、体積比で合計６０％以上含んでいてもよく、７０％以上含んでいてもよく、８０％以上含んでいてもよく、９０％以上含んでいてもよい。 The structure 1 may include a crystalline portion 10 and an amorphous portion 20 as main components. Here, the term "main component" means that the structure 1 includes crystalline portions 10 and amorphous portions 20 in a total volume ratio of 50% or more. The crystalline portion 10 and the amorphous portion 20 may contain a total volume ratio of 60% or more, 70% or more, 80% or more, or 90% or more of the structure 1 by volume. % or more.
　結晶部１０と非晶質部２０とは、構造体１に対し、モル比で合計５０％以上含んでいてもよく、６０％以上含んでいてもよく、７０％以上含んでいてもよく、８０％以上含んでいてもよく、９０％以上含んでいてもよい。 The crystalline portion 10 and the amorphous portion 20 may have a total molar ratio of 50% or more, 60% or more, 70% or more, and 80% or more of the structure 1. % or more, or 90% or more.
　図２に示すように、構造体１は、平均粒子径が１００ｎｍ以上の複数の無機粒子３０を備えていてもよい。構造体１がこのような無機粒子３０を備えることにより、無機粒子３０が骨材として機能することから、構造体１の強度を高めることができる。無機粒子３０の平均粒子径は、１μｍ以上であってもよく、５μｍ以上であってもよく、１０μｍ以上であってもよい。また、複数の無機粒子３０の平均粒子径は、５０μｍ以下であってもよく、３０μｍ以下であってもよい。なお、本明細書において、「平均粒子径」の値としては、特に言及のない限り、走査型電子顕微鏡（ＳＥＭ）又は透過型電子顕微鏡（ＴＥＭ）などの観察手段を用い、数～数十視野中に観察される粒子の粒子径の平均値として算出される値を採用する。 As shown in FIG. 2, the structure 1 may include a plurality of inorganic particles 30 having an average particle diameter of 100 nm or more. When the structure 1 includes such inorganic particles 30, the inorganic particles 30 function as an aggregate, so that the strength of the structure 1 can be increased. The average particle diameter of the inorganic particles 30 may be 1 μm or more, 5 μm or more, or 10 μm or more. Moreover, the average particle diameter of the plurality of inorganic particles 30 may be 50 μm or less, or may be 30 μm or less. In this specification, unless otherwise specified, the value of "average particle diameter" refers to a field of view of several to several tens of fields using an observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM). The value calculated as the average value of the particle diameter of the particles observed in the sample is adopted.
　無機粒子３０の形状は特に限定されないが、例えば球状とすることができる。また、無機粒子３０は、ウィスカー状（針状）の粒子、又は鱗片状の粒子であってもよい。ウィスカー状粒子又は鱗片状粒子は、球状粒子と比べて他の粒子との接触性が高まるため、構造体１全体の強度を高めることが可能となる。 The shape of the inorganic particles 30 is not particularly limited, but may be, for example, spherical. Further, the inorganic particles 30 may be whisker-like (acicular) particles or scale-like particles. Since whisker-like particles or scale-like particles have higher contactability with other particles than spherical particles, it is possible to increase the strength of the entire structure 1.
　無機粒子３０の屈折率は、ＺｎＡｌ２Ｏ４の屈折率以下であってもよく、ＺｎＡｌ２Ｏ４の屈折率より小さくてもよい。これにより、構造体１内での光の乱反射を抑制することができる。また、無機粒子３０の屈折率は、非晶質部２０に含まれ、亜鉛及びアルミニウムを有する非晶質化合物の屈折率以下であってもよく、上記非晶質化合物の屈折率より小さくてもよい。これにより、構造体１内での光の乱反射を抑制することができる。そのため、透光性の高い構造体１を提供することができる。 The refractive index of the inorganic particles 30 may be less than or equal to the refractive index of ZnAl 2 O 4 or may be smaller than the refractive index of ZnAl 2 O 4 . Thereby, diffuse reflection of light within the structure 1 can be suppressed. Further, the refractive index of the inorganic particles 30 may be less than or equal to the refractive index of an amorphous compound containing zinc and aluminum that is included in the amorphous portion 20, or may be smaller than the refractive index of the amorphous compound. good. Thereby, diffuse reflection of light within the structure 1 can be suppressed. Therefore, it is possible to provide a structure 1 with high translucency.
　無機粒子３０は無機物質で構成されており、当該無機物質は、アルカリ金属、アルカリ土類金属、遷移金属、卑金属及び半金属からなる群より選ばれる少なくとも一つの金属元素を含有していてもよい。本明細書において、アルカリ土類金属は、カルシウム、ストロンチウム、バリウム及びラジウムに加えて、ベリリウム及びマグネシウムを包含する。遷移金属は、例えば、スカンジウム、チタン、バナジウム、クロム、マンガン、鉄、コバルト、ニッケル、銅、イットリウム、ジルコニウム、ニオブ、モリブデン、ルテニウム、ロジウム、パラジウム、銀、タングステン、白金、金を包含する。卑金属は、アルミニウム、亜鉛、ガリウム、カドミウム、インジウム、すず、水銀、タリウム、鉛、ビスマス及びポロニウムを包含する。半金属は、ホウ素、ケイ素、ゲルマニウム、ヒ素、アンチモン及びテルルを包含する。 The inorganic particles 30 are composed of an inorganic substance, and the inorganic substance may contain at least one metal element selected from the group consisting of alkali metals, alkaline earth metals, transition metals, base metals, and metalloids. . As used herein, alkaline earth metals include beryllium and magnesium in addition to calcium, strontium, barium and radium. Transition metals include, for example, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, yttrium, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, silver, tungsten, platinum, and gold. Base metals include aluminum, zinc, gallium, cadmium, indium, tin, mercury, thallium, lead, bismuth and polonium. Metalloids include boron, silicon, germanium, arsenic, antimony and tellurium.
　無機粒子３０を構成する無機物質は、例えば、上記金属元素の酸化物、窒化物、水酸化物、酸化水酸化物、硫化物、ホウ化物、炭化物及びハロゲン化物からなる群より選ばれる少なくとも一つであってもよい。無機粒子３０を構成する無機物質は、上記金属元素の酸化物であってもよい。無機粒子３０を構成する無機物質は単純金属酸化物又は複合金属酸化物であってもよい。単純金属酸化物に含まれる金属元素は一種であり、複合金属酸化物に含まれる金属元素は二種以上である。無機粒子３０に含まれる無機物質は、結晶質化合物であってもよく、非晶質化合物であってもよい。無機粒子３０は、ＺｎＡｌ２Ｏ４を含んでいてもよい。無機粒子３０が結晶部１０と同じＺｎＡｌ２Ｏ４を含むことにより、透光性を維持しつつ、構造体１の強度を高めることができる。 The inorganic substance constituting the inorganic particles 30 is, for example, at least one selected from the group consisting of oxides, nitrides, hydroxides, hydroxide oxides, sulfides, borides, carbides, and halides of the above metal elements. It may be. The inorganic substance constituting the inorganic particles 30 may be an oxide of the above metal element. The inorganic substance constituting the inorganic particles 30 may be a simple metal oxide or a composite metal oxide. A simple metal oxide contains one kind of metal element, and a complex metal oxide contains two or more kinds of metal elements. The inorganic substance contained in the inorganic particles 30 may be a crystalline compound or an amorphous compound. The inorganic particles 30 may contain ZnAl 2 O 4 . Since the inorganic particles 30 contain the same ZnAl 2 O 4 as the crystal part 10, the strength of the structure 1 can be increased while maintaining translucency.
　無機粒子３０は、上記金属元素の酸化物を主成分として含有していてもよい。無機粒子３０は、上記金属元素の酸化物を８０ｍｏｌ％以上含有していてもよく、９０ｍｏｌ％以上含有していてもよく、９５ｍｏｌ％以上含有していてもよい。 The inorganic particles 30 may contain an oxide of the above metal element as a main component. The inorganic particles 30 may contain 80 mol% or more of the above metal element oxide, may contain 90 mol% or more, or may contain 95 mol% or more.
　構造体１において、複数の無機粒子３０の体積割合は３０％以上であってもよい。この場合、得られる構造体１は、無機粒子３０の特性を活用しやすい構造体１となる。また、構造体１において、複数の無機粒子３０の体積割合は４０％以上であってもよく、５０％以上であってもよい。無機粒子３０の体積割合は非晶質部２０の体積割合よりも大きくてもよい。 In the structure 1, the volume ratio of the plurality of inorganic particles 30 may be 30% or more. In this case, the obtained structure 1 becomes a structure 1 in which the characteristics of the inorganic particles 30 can be easily utilized. Further, in the structure 1, the volume ratio of the plurality of inorganic particles 30 may be 40% or more, or may be 50% or more. The volume ratio of the inorganic particles 30 may be larger than the volume ratio of the amorphous portion 20.
　構造体１は、結晶部１０、非晶質部２０及び無機粒子３０に加え、有機物や樹脂粒子が含まれていてもよい。後述するように、構造体１は１００～３００℃に加熱しながら加圧することにより得ることができるため、構造体１に耐熱性の低い部材を添加することができる。また、有機物等の耐熱性の低い部材に限定されず、構造体１は、結晶部１０、非晶質部２０及び無機粒子３０以外の無機化合物を含む粒子が含まれていてもよい。 In addition to the crystal part 10, the amorphous part 20, and the inorganic particles 30, the structure 1 may contain organic matter and resin particles. As will be described later, since the structure 1 can be obtained by applying pressure while heating to 100 to 300° C., a member with low heat resistance can be added to the structure 1. Furthermore, the structure 1 is not limited to a member having low heat resistance such as an organic substance, and may include particles containing an inorganic compound other than the crystal part 10, the amorphous part 20, and the inorganic particles 30.
　構造体１に含まれる無機物質は、カルシウム化合物の水和物を含まないことが好ましい。ここでいうカルシウム化合物は、ケイ酸三カルシウム（エーライト、３ＣａＯ・ＳｉＯ２）、ケイ酸二カルシウム（ビーライト、２ＣａＯ・ＳｉＯ２）、カルシウムアルミネート（３ＣａＯ・Ａｌ２Ｏ３）、カルシウムアルミノフェライト（４ＣａＯ・Ａｌ２Ｏ３・Ｆｅ２Ｏ３）、硫酸カルシウム（ＣａＳＯ４・２Ｈ２Ｏ）である。構造体１に含まれる無機物質が上記カルシウム化合物の水和物を含まないことにより、構造体１の断面における気孔率が低下することから、機械的強度を高めることができる。そのため、無機物質は、上記カルシウム化合物の水和物を含まないことが好ましい。また、構造体１に含まれる無機物質は、リン酸セメント、リン酸亜鉛セメント、及びリン酸カルシウムセメントも含まないことが好ましい。無機物質がこれらのセメントを含まないことにより、構造体１の断面における気孔率が低下することから、機械的強度を高めることができる。 The inorganic substance contained in the structure 1 preferably does not contain a hydrate of a calcium compound. The calcium compounds mentioned here include tricalcium silicate (alite, 3CaO・SiO 2 ), dicalcium silicate (belite, 2CaO・SiO 2 ), calcium aluminate (3CaO・Al 2 O 3 ), and calcium aluminoferrite. (4CaO.Al 2 O 3.Fe 2 O 3 ) and calcium sulfate (CaSO 4.2H 2 O). Since the inorganic substance contained in the structure 1 does not contain a hydrate of the above-mentioned calcium compound, the porosity in the cross section of the structure 1 is reduced, so that the mechanical strength can be increased. Therefore, it is preferable that the inorganic substance does not contain a hydrate of the calcium compound. Further, it is preferable that the inorganic substance contained in the structure 1 does not include phosphate cement, zinc phosphate cement, or calcium phosphate cement. Since the inorganic substance does not contain these cements, the porosity in the cross section of the structure 1 is reduced, so that the mechanical strength can be increased.
　構造体１の断面における気孔率は２０％以下である。すなわち、構造体１の断面を観察した場合、単位面積あたりの気孔の割合の平均値が２０％以下である。気孔率が２０％以下の場合、構造体１が緻密になり、強度が高まる。そのため、構造体１の機械加工性を向上させることが可能となる。また、気孔率が２０％以下の場合には、気孔を起点として、構造体１にひび割れが発生することが抑制されるため、構造体１の曲げ強さを高めることが可能となる。なお、構造体１の断面における気孔率は１０％以下であることが好ましく、８％以下であることがより好ましく、５％以下であることがさらに好ましく、１％以下であることが特に好ましい。構造体１の断面における気孔率が小さいほど、気孔を起点としたひび割れが抑制されるため、構造体１の強度を高めることが可能となる。 The porosity in the cross section of the structure 1 is 20% or less. That is, when observing the cross section of the structure 1, the average value of the ratio of pores per unit area is 20% or less. When the porosity is 20% or less, the structure 1 becomes dense and its strength increases. Therefore, it becomes possible to improve the machinability of the structure 1. Further, when the porosity is 20% or less, cracks are suppressed from occurring in the structure 1 starting from the pores, so that the bending strength of the structure 1 can be increased. The porosity in the cross section of the structure 1 is preferably 10% or less, more preferably 8% or less, even more preferably 5% or less, and particularly preferably 1% or less. The smaller the porosity in the cross section of the structure 1, the more suppressed are cracks originating from the pores, making it possible to increase the strength of the structure 1.
　本明細書において、気孔率は次のように求めることができる。まず、構造体１の断面を観察し、気孔と気孔以外とを判別する。そして、単位面積と当該単位面積中の気孔の面積とを測定し、単位面積あたりの気孔の割合を求め、その値を気孔率とする。なお、構造体１の断面に対し、単位面積あたりの気孔の割合を複数箇所で求めた後、単位面積あたりの気孔の割合の平均値を気孔率とすることがより好ましい。構造体１の断面を観察する際には、光学顕微鏡、走査型電子顕微鏡（ＳＥＭ）又は透過型電子顕微鏡（ＴＥＭ）を用いることができる。また、単位面積と当該単位面積中の気孔の面積は、顕微鏡で観察した画像を二値化することにより測定してもよい。 In this specification, porosity can be determined as follows. First, a cross section of the structure 1 is observed to distinguish between pores and non-pores. Then, the unit area and the area of pores in the unit area are measured, the ratio of pores per unit area is determined, and this value is defined as the porosity. It is more preferable to determine the pore ratio per unit area at a plurality of locations in the cross section of the structure 1, and then use the average value of the pore ratio per unit area as the porosity. When observing the cross section of the structure 1, an optical microscope, a scanning electron microscope (SEM), or a transmission electron microscope (TEM) can be used. Further, the unit area and the area of pores within the unit area may be measured by binarizing an image observed with a microscope.
　構造体１の内部に存在する気孔の大きさは特に限定されないが、可能な限り小さい方が好ましい。気孔の大きさが小さいことにより、気孔を起点としたひび割れが抑制されるため、構造体１の強度を高め、構造体１の機械加工性を向上させることが可能となる。なお、構造体１の気孔の大きさは、５μｍ以下であることが好ましく、１μｍ以下であることがより好ましく、１００ｎｍ以下であることがさらに好ましい。構造体１の内部に存在する気孔の大きさは、上述の気孔率と同様に、構造体１の断面を顕微鏡で観察することにより、求めることができる。 The size of the pores existing inside the structure 1 is not particularly limited, but is preferably as small as possible. Since the size of the pores is small, cracks originating from the pores are suppressed, so that the strength of the structure 1 can be increased and the machinability of the structure 1 can be improved. Note that the size of the pores in the structure 1 is preferably 5 μm or less, more preferably 1 μm or less, and even more preferably 100 nm or less. Similar to the porosity described above, the size of the pores existing inside the structure 1 can be determined by observing the cross section of the structure 1 with a microscope.
　波長５５０ｎｍにおける構造体１の全透過率は５％以上である。上記のように、ＺｎＡｌ２Ｏ４の結晶子サイズが小さく、構造体１の気孔率も小さいため、透光性を有する構造体１を提供することができる。このような構造体１は、光学部材として用いることができる。全透過率は１０％以上であってもよく、２０％以上であってもよく、３０％以上であってもよい。全透過率は、ＪＩＳ　Ｂ７０８１の規定に従って測定することができる。 The total transmittance of the structure 1 at a wavelength of 550 nm is 5% or more. As described above, since the crystallite size of ZnAl 2 O 4 is small and the porosity of the structure 1 is also small, it is possible to provide the structure 1 having translucency. Such a structure 1 can be used as an optical member. The total transmittance may be 10% or more, 20% or more, or 30% or more. The total transmittance can be measured according to the regulations of JIS B7081.
　構造体１の形状は特に限定されず、例えば板状、膜状、矩形状、塊状、棒状、球状であってもよい。また、構造体１が板状又は膜状の場合、その厚みは特に限定されないが、例えば５０μｍ以上とすることができる。本実施形態の構造体１は、後述するように、加圧加熱法により形成される。そのため、厚みの大きな構造体１を容易に得ることができる。なお、構造体１の厚みは５００μｍ以上、１ｍｍ以上、又は１ｃｍ以上とすることもできる。構造体１の厚みの上限は特に限定されないが、例えば５０ｃｍとすることができる。 The shape of the structure 1 is not particularly limited, and may be, for example, plate-like, film-like, rectangular, block-like, rod-like, or spherical. Further, when the structure 1 is plate-shaped or film-shaped, the thickness thereof is not particularly limited, but may be, for example, 50 μm or more. The structure 1 of this embodiment is formed by a pressure heating method, as will be described later. Therefore, a thick structure 1 can be easily obtained. Note that the thickness of the structure 1 can also be set to 500 μm or more, 1 mm or more, or 1 cm or more. The upper limit of the thickness of the structure 1 is not particularly limited, but may be, for example, 50 cm.
　以上説明したように、本実施形態に係る構造体１は、ＺｎＡｌ２Ｏ４の結晶部１０と、隣接する結晶部１０を結合し、亜鉛及びアルミニウムを有する非晶質化合物を含む非晶質部２０と、を備えている。ＺｎＡｌ２Ｏ４の結晶子サイズは２０ｎｍ以下であり、気孔率は２０％以下であり、波長５５０ｎｍにおける全透過率は５％以上であり、非晶質部２０はＳｉを実質的に含まない。このような構造体１は、後述するように、簡易な方法で作製することが可能であり、緻密で透光性を有する。 As explained above, the structure 1 according to the present embodiment combines a ZnAl 2 O 4 crystal part 10 and an adjacent crystal part 10, and forms an amorphous part containing an amorphous compound containing zinc and aluminum. It is equipped with 20. The crystallite size of ZnAl 2 O 4 is 20 nm or less, the porosity is 20% or less, the total transmittance at a wavelength of 550 nm is 5% or more, and the amorphous portion 20 does not substantially contain Si. As described later, such a structure 1 can be manufactured by a simple method, and is dense and translucent.
　＜構造体を備える部材＞
　次に、構造体１を備える部材について説明する。構造体１は、上述のように、厚みの大きな板状とすることができ、さらに緻密であるため化学的安定性にも優れている。また、構造体１は、機械的強度が高く、一般的なセラミックス部材と同様に切断することができると共に、表面加工することもできる。そのため、構造体１は、光学部材として好適に用いることができる。光学部材としては特に限定されないが、例えば、窓材、フィルタ及びレンズなどを挙げることができる。 <Member with structure>
Next, a member including the structure 1 will be explained. As described above, the structure 1 can be formed into a thick plate shape, and is also dense and has excellent chemical stability. Further, the structure 1 has high mechanical strength, can be cut like a general ceramic member, and can also be surface-treated. Therefore, the structure 1 can be suitably used as an optical member. Although the optical member is not particularly limited, examples thereof include window materials, filters, lenses, and the like.
　＜構造体の製造方法＞
　次に、構造体１の製造方法について説明する。構造体１の製造方法は、層状複水酸化物とアルミニウムを含む水酸化物とを含む混合物を、加圧及び加熱する工程を含んでいる。これにより、緻密な構造体１を得ることができる。混合物に含まれる層状複水酸化物は粒子であってもよい。層状複水酸化物粒子の平均粒子径は１００ｎｍ未満であってもよい。また、混合物に含まれる水酸化物は粒子であってもよい。水酸化物粒子の平均粒子径は１００ｎｍ未満であってもよい。 <Method for manufacturing structure>
Next, a method for manufacturing the structure 1 will be described. The method for manufacturing the structure 1 includes the steps of pressurizing and heating a mixture containing a layered double hydroxide and a hydroxide containing aluminum. Thereby, a dense structure 1 can be obtained. The layered double hydroxide contained in the mixture may be in the form of particles. The average particle diameter of the layered double hydroxide particles may be less than 100 nm. Furthermore, the hydroxide contained in the mixture may be in the form of particles. The average particle diameter of the hydroxide particles may be less than 100 nm.
　層状複水酸化物は亜鉛とアルミニウムとを含んでいる。このような層状複水酸化物は、原子レベルで両金属イオンが混合している。そのため、このような層状複水酸化物を原料として用いることにより、例えば水酸化亜鉛及び水酸化アルミニウムを原料に用いた場合と比較し、反応の際に元素拡散距離を短くすることができる。したがって、低温条件下であっても、ＺｎＡｌ２Ｏ４を容易に形成することができる。また、層状複水酸化物はＺｎ源とＡｌ源とが原子レベルで均一に混ざっているため、加熱及び加圧により、ＺｎＯやＡｌＯＯＨなどの不純物が生成するのを抑制することができる。 The layered double hydroxide contains zinc and aluminum. In such a layered double hydroxide, both metal ions are mixed at the atomic level. Therefore, by using such a layered double hydroxide as a raw material, it is possible to shorten the elemental diffusion distance during the reaction, compared to the case where, for example, zinc hydroxide and aluminum hydroxide are used as raw materials. Therefore, ZnAl 2 O 4 can be easily formed even under low temperature conditions. Furthermore, since the layered double hydroxide has a Zn source and an Al source uniformly mixed at the atomic level, it is possible to suppress the generation of impurities such as ZnO and AlOOH by heating and pressurization.
　層状複水酸化物は［Ｍ２＋ １－ｘＭ３＋ ｘ（ＯＨ）２］［Ａｍ－］ｘ／ｍ・ｎＨ２Ｏの組成式で表される化合物である（ここで、Ｍ２＋はＭｇ２＋，Ｚｎ２＋，Ｃｏ２＋，Ｎｉ２＋及びＣｕ２＋などの二価金属、Ｍ３＋はＡｌ３＋，Ｇａ３＋，Ｃｒ３＋，Ｆｅ３＋及びＭｎ３＋などの三価金属、Ａｍ－はＣＯ３ ２－，ＮＯ３ －及びＣｌ－などのアニオンを表し、ｘは１／４～１／３である）。 Layered double hydroxide is a compound represented by the composition formula [M 2+ 1-x M 3+ x (OH) 2 ][A m- ] x/m ·nH 2 O (here, M 2+ is Mg 2+ , Zn 2+ , Co 2+ , Ni 2+ and Cu 2+ , M 3+ is a trivalent metal such as Al 3+ , Ga 3+ , Cr 3+ , Fe 3+ and Mn 3+ , A m- is CO 3 2- , NO 3 - and Cl - , and x is 1/4 to 1/3).
　層状複水酸化物はＬＤＨとも言われており、［Ｍ２＋ １－ｘＭ３＋ ｘ（ＯＨ）２］で表される複水酸化物層が積層した積層構造を形成している。層状複水酸化物は、［Ｍ２＋ １－ｘＭ３＋ ｘ（ＯＨ）２］で表される複水酸化物層の層間に、［Ａｍ－］ｘ／ｍ・ｎＨ２Ｏで表される中間層が介在するサンドイッチ構造が積層された積層構造を形成している。複水酸化物層は、金属イオンが八面体の中心に位置し、辺を共有した二次元シートを形成していてもよい。複水酸化物層は、Ｍｇ（ＯＨ）２（Ｂｒｕｃｉｔｅ）型の八面体層における一部のＭ２＋がＭ３＋で置換されており、正に帯電している。複水酸化物層の正電荷は、水和されたアニオンを含む層によって打ち消されている。 Layered double hydroxide is also called LDH, and forms a layered structure in which double hydroxide layers represented by [M 2+ 1-x M 3+ x (OH) 2 ] are stacked. The layered double hydroxide has a layer of double hydroxide represented by [M 2+ 1-x M 3+ x (OH) 2 ], between which there is a layer of [ A m- ] A sandwich structure with an intervening intermediate layer is stacked to form a laminate structure. The double hydroxide layer may form a two-dimensional sheet in which metal ions are located at the center of an octahedron and share edges. In the double hydroxide layer, some M 2+ in the Mg(OH) 2 (Brucite) type octahedral layer is replaced with M 3+ and is positively charged. The positive charge of the double hydroxide layer is counteracted by the layer containing hydrated anions.
　本実施形態では、Ｍ２＋がＺｎ２＋であり、Ｍ３＋がＡｌ３＋であり、Ａｍ－がＣＯ３ ２－である層状複水酸化物の例について説明する。すなわち、層状複水酸化物は［Ｚｎ２＋ １－ｘＡｌ３＋ ｘ（ＯＨ）２］［ＣＯ３ ２－］ｘ／２・ｎＨ２Ｏの組成式で表される化合物であってもよい。より具体的には、ｘが１／３であってもよい。すなわち、層状複水酸化物は［Ｚｎ２＋ ２／３Ａｌ３＋ １／３（ＯＨ）２］［ＣＯ３ ２－］１／６・ｎＨ２Ｏの組成式で表される化合物であってもよい。層状複水酸化物は結晶質であってもよい。 In this embodiment, an example of a layered double hydroxide in which M 2+ is Zn 2+ , M 3+ is Al 3+ , and A m- is CO 3 2- will be described. That is, the layered double hydroxide may be a compound represented by the composition formula [Zn 2+ 1-x Al 3+ x (OH) 2 ][CO 3 2- ] x/2 ·nH 2 O. More specifically, x may be 1/3. That is, the layered double hydroxide may be a compound represented by the composition formula [Zn 2+ 2/3 Al 3+ 1/3 (OH) 2 ][CO 3 2- ] 1/6 ·nH 2 O. . The layered double hydroxide may be crystalline.
　混合物に含まれる水酸化物はアルミニウムを含んでいる。水酸化物は、具体的には、水酸化アルミニウム（Ａｌ（ＯＨ）３）であってもよい。アルミニウムを含む水酸化物は、非晶質であってもよい。 The hydroxide contained in the mixture contains aluminum. The hydroxide may specifically be aluminum hydroxide (Al(OH) 3 ). The hydroxide containing aluminum may be amorphous.
　混合物の調製方法は特に限定されず、公知の方法によって調製することができる。層状複水酸化物とアルミニウムを含む水酸化物とを含む混合物は、逆共沈法によって調製してもよい。逆共沈法は、亜鉛イオン及びアルミニウムイオンを含む混合溶液をアルカリ溶液に滴下することで、層状複水酸化物とアルミニウムを含む水酸化物とを含む混合物を生成することができる。逆共沈法では、亜鉛イオンとアルミニウムイオンとをイオンレベルで混合することができるため、低い加熱温度でＺｎＡｌ２Ｏ４を生成することができる。 The method for preparing the mixture is not particularly limited, and the mixture can be prepared by any known method. A mixture containing a layered double hydroxide and a hydroxide containing aluminum may be prepared by a reverse coprecipitation method. In the reverse coprecipitation method, a mixture containing a layered double hydroxide and a hydroxide containing aluminum can be produced by dropping a mixed solution containing zinc ions and aluminum ions into an alkaline solution. In the reverse coprecipitation method, zinc ions and aluminum ions can be mixed at the ion level, so ZnAl 2 O 4 can be produced at a low heating temperature.
　亜鉛イオン及びアルミニウムイオンを含む混合溶液は、亜鉛塩及びアルミニウム塩を溶媒に溶解することで得ることができる。亜鉛塩としては、例えば塩化亜鉛などが挙げられる。アルミニウム塩としては、例えば塩化アルミニウムなどが挙げられる。溶媒としては、水などが挙げられる。 A mixed solution containing zinc ions and aluminum ions can be obtained by dissolving zinc salts and aluminum salts in a solvent. Examples of zinc salts include zinc chloride. Examples of aluminum salts include aluminum chloride. Examples of the solvent include water.
　混合溶液に含まれる亜鉛イオンに対するアルミニウムイオンのモル比は、例えば１．５以上２．５以上である。上記モル比は１．８以上であってもよく、１．９以上であってもよい。また、上記モル比は、２．３以下であってもよく、２．１以下であってもよい。 The molar ratio of aluminum ions to zinc ions contained in the mixed solution is, for example, 1.5 or more and 2.5 or more. The molar ratio may be 1.8 or more, or 1.9 or more. Further, the molar ratio may be 2.3 or less, or 2.1 or less.
　混合溶液中の亜鉛及びアルミニウムの合計金属イオン濃度は、２００ｍｍｏｌ／Ｌ以上８００ｍｍｏｌ／Ｌ以下であってもよい。上記金属イオン濃度は、３００ｍｍｏｌ／Ｌ以上であってもよく、４００ｍｍｏｌ／Ｌ以上であってもよい。上記金属イオン濃度は、７００ｍｍｏｌ／Ｌ以下であってもよく、６００ｍｍｏｌ／Ｌ以下であってもよい。 The total metal ion concentration of zinc and aluminum in the mixed solution may be 200 mmol/L or more and 800 mmol/L or less. The metal ion concentration may be 300 mmol/L or more, or 400 mmol/L or more. The metal ion concentration may be 700 mmol/L or less, or 600 mmol/L or less.
　混合溶液に含まれる亜鉛イオン濃度は、７０ｍｍｏｌ／Ｌ以上２６０ｍｍｏｌ／Ｌ以下であってもよい。亜鉛イオン濃度は、１００ｍｍｏｌ／Ｌ以上であってもよく、１３０ｍｍｏｌ／Ｌ以上であってもよい。亜鉛イオン濃度は、２３０ｍｍｏｌ／Ｌ以下であってもよく、２００ｍｍｏｌ／Ｌ以下であってもよい。 The zinc ion concentration contained in the mixed solution may be 70 mmol/L or more and 260 mmol/L or less. The zinc ion concentration may be 100 mmol/L or more, or 130 mmol/L or more. The zinc ion concentration may be 230 mmol/L or less, or 200 mmol/L or less.
　混合溶液に含まれるアルミニウムイオン濃度は１４０ｍｍｏｌ／Ｌ以上５２０ｍｍｏｌ／Ｌ以下であってもよい。アルミニウムイオン濃度は、２００ｍｍｏｌ／Ｌ以上であってもよく、２６０ｍｍｏｌ／Ｌ以上であってもよい。アルミニウムイオン濃度は、４６０ｍｍｏｌ／Ｌ以下であってもよく、４００ｍｍｏｌ／Ｌ以下であってもよい。 The aluminum ion concentration contained in the mixed solution may be 140 mmol/L or more and 520 mmol/L or less. The aluminum ion concentration may be 200 mmol/L or more, or 260 mmol/L or more. The aluminum ion concentration may be 460 mmol/L or less, or 400 mmol/L or less.
　アルカリ溶液は、例えば炭酸ナトリウム（Ｎａ２ＣＯ３）水溶液であってもよい。炭酸ナトリウム水溶液の濃度は、例えば、８００ｍｍｏｌ／Ｌ以上１２００ｍｍｏｌ／Ｌ以下であってもよい。アルカリ溶液のｐＨは７以上１０．５以下であってもよい。混合溶液の滴下時において、アルカリ溶液のｐＨは、水酸化ナトリウム水溶液などで調製してもよい。 The alkaline solution may be, for example, an aqueous sodium carbonate (Na 2 CO 3 ) solution. The concentration of the sodium carbonate aqueous solution may be, for example, 800 mmol/L or more and 1200 mmol/L or less. The pH of the alkaline solution may be 7 or more and 10.5 or less. At the time of dropping the mixed solution, the pH of the alkaline solution may be adjusted with an aqueous sodium hydroxide solution or the like.
　混合物は、平均粒子径が１００ｎｍ以上の複数の無機粒子をさらに含んでいてもよい。無機粒子は、上述した無機粒子３０と同様のものを採用することができる。具体的には、混合物に含まれる無機粒子の平均粒子径、形状、屈折率、材質、特性などは上述した無機粒子３０と同様のものを採用することができる。 The mixture may further contain a plurality of inorganic particles having an average particle diameter of 100 nm or more. The same inorganic particles as the inorganic particles 30 described above can be used as the inorganic particles. Specifically, the average particle diameter, shape, refractive index, material, characteristics, etc. of the inorganic particles contained in the mixture can be the same as those of the inorganic particles 30 described above.
　次に、層状複水酸化物とアルミニウムを含む水酸化物とを含む混合物を、加圧及び加熱する。混合物は、純水又はイオン交換水などのような水を含んでいてもよい。混合物を金型の内部に充填し、加圧及び加熱してもよい。混合物を金型に充填した後、必要に応じて金型を加熱してもよい。金型の内部の混合物に圧力を加えることにより、金型の内部が高圧状態となる。そして、加圧及び加熱された混合物を金型の内部から取り出すことにより、構造体１を得ることができる。 Next, the mixture containing the layered double hydroxide and the hydroxide containing aluminum is pressurized and heated. The mixture may also include water, such as pure water or ion-exchanged water. The mixture may be filled inside a mold, pressurized and heated. After filling the mold with the mixture, the mold may be heated if necessary. By applying pressure to the mixture inside the mold, a high pressure state is created inside the mold. The structure 1 can then be obtained by taking out the pressurized and heated mixture from inside the mold.
　混合物の加圧及び加熱する条件は、層状複水酸化物とアルミニウムを含む水酸化物との反応が進行するような条件であれば特に限定されない。例えば、上記混合物を１００～３００℃に加熱しつつ、１０～６００ＭＰａの圧力で加圧することが好ましい。なお、上記混合物を加熱する際の温度は、１００～２５０℃であることがより好ましく、１００～２００℃であることがさらに好ましい。また、上記混合物を加圧する際の圧力は、５０～６００ＭＰａであることがより好ましく、２００～６００ＭＰａであることがさらに好ましい。加圧時間は１分～３６０分であることが好ましく、１０分～２４０分であることがより好ましい。 The conditions for pressurizing and heating the mixture are not particularly limited as long as the reaction between the layered double hydroxide and the hydroxide containing aluminum proceeds. For example, it is preferable to pressurize the mixture at a pressure of 10 to 600 MPa while heating the mixture to 100 to 300°C. The temperature at which the mixture is heated is preferably 100 to 250°C, and even more preferably 100 to 200°C. Further, the pressure when pressurizing the above mixture is more preferably 50 to 600 MPa, and even more preferably 200 to 600 MPa. The pressurizing time is preferably 1 minute to 360 minutes, more preferably 10 minutes to 240 minutes.
　混合物が加圧及び加熱されることにより、層状複水酸化物から水が脱離するとともに、ＺｎＡｌ２Ｏ４が生成される。この際、脱離水によって一時的な水熱環境が形成され、Ｚｎ及びＡｌが水に溶解及び再析出することによって拡散し、例えば以下の反応式に示すようなＺｎＡｌ２Ｏ４の結晶部１０の生成が促進されると推定される。 By pressurizing and heating the mixture, water is desorbed from the layered double hydroxide and ZnAl 2 O 4 is generated. At this time, a temporary hydrothermal environment is formed by the desorbed water, and Zn and Al are dissolved in water and reprecipitated to diffuse, and for example, the ZnAl 2 O 4 crystal part 10 as shown in the following reaction formula is formed. It is estimated that the production is promoted.
　［Ｚｎ２＋ ２／３Ａｌ３＋ １／３（ＯＨ）２］［ＣＯ３ ２－］１／６・２／３Ｈ２Ｏ＋Ａｌ（ＯＨ）３→２／３ＺｎＡｌ２Ｏ４＋１／６ＣＯ２＋１９／６Ｈ２Ｏ [Zn 2+ 2/3 Al 3+ 1/3 (OH) 2 ] [CO 3 2- ] 1/6・2/3H 2 O+Al(OH) 3 → 2/3ZnAl 2 O 4 +1/6CO 2 +19/6H 2 O
　また、水熱環境下で混合物が加圧及び加熱されることにより、層状複水酸化物の一部が脱水し、亜鉛及びアルミニウムを有する非晶質化合物が生成されると推定される。 Furthermore, it is estimated that when the mixture is pressurized and heated in a hydrothermal environment, a portion of the layered double hydroxide is dehydrated and an amorphous compound containing zinc and aluminum is generated.
　上記のような加圧及び加熱による反応により、緻密な構造を有する構造体１を得ることができる。また、無機粒子の凝集体を形成する方法として、無機粒子の粉末のみをプレスして圧粉体を形成した後、高温（例えば１７００℃以上）で焼結する方法も考えられる。しかしながら、無機粒子の圧粉体を高温で焼結しても、得られる構造体１には多くの気孔が存在し、機械的強度が不十分となる。また、無機粒子を高温で焼結する場合、緻密な温度制御が必要となるため、製造コストが増加してしまう。 The structure 1 having a dense structure can be obtained by the reaction under pressure and heating as described above. Further, as a method of forming an aggregate of inorganic particles, a method of pressing only the powder of inorganic particles to form a green compact and then sintering the compact at a high temperature (for example, 1700° C. or higher) is also considered. However, even if the green compact of inorganic particles is sintered at a high temperature, the resulting structure 1 will have many pores and will have insufficient mechanical strength. Furthermore, when inorganic particles are sintered at high temperatures, precise temperature control is required, which increases manufacturing costs.
　これに対して、本実施形態の製造方法では、層状複水酸化物と、アルミニウムを含む水酸化物とを含む混合物を加熱しながら加圧しているため、緻密かつ強度に優れた構造体１を得ることができる。さらに、本実施形態の製造方法は、１００℃～３００℃で加熱しながら加圧することにより得ることができるため、緻密な温度制御が不要となり、製造コストを低減することが可能となる。 On the other hand, in the manufacturing method of the present embodiment, the mixture containing the layered double hydroxide and the hydroxide containing aluminum is heated and pressurized, so that the structure 1 is dense and has excellent strength. Obtainable. Furthermore, since the manufacturing method of this embodiment can be obtained by applying pressure while heating at 100° C. to 300° C., precise temperature control is not required and manufacturing costs can be reduced.
　このように、本実施形態の構造体１の製造方法は、亜鉛とアルミニウムとを含む層状複水酸化物と、アルミニウムを含む水酸化物とを含む混合物を、圧力が１０～６００ＭＰａであり、かつ、温度が１００～３００℃である条件下で加圧及び加熱する工程を含む。波長５５０ｎｍにおける構造体１の全透過率は５％以上であり、構造体１は非晶質化合物を含む非晶質部２０を備え、非晶質部２０はＳｉを実質的に含まない。そのため、本実施形態の製造方法は、緻密で透光性を有する構造体１を、簡易な方法で作製することができる。 As described above, the method for manufacturing the structure 1 of the present embodiment is to produce a mixture containing a layered double hydroxide containing zinc and aluminum and a hydroxide containing aluminum at a pressure of 10 to 600 MPa, and , a step of pressurizing and heating at a temperature of 100 to 300°C. The total transmittance of the structure 1 at a wavelength of 550 nm is 5% or more, the structure 1 includes an amorphous portion 20 containing an amorphous compound, and the amorphous portion 20 does not substantially contain Si. Therefore, according to the manufacturing method of this embodiment, the dense and translucent structure 1 can be manufactured using a simple method.
　以下、本実施形態を実施例によりさらに詳細に説明するが、本実施形態はこのような実施例に限定されるものではない。 Hereinafter, this embodiment will be described in more detail with reference to Examples, but this embodiment is not limited to such Examples.
　（実施例）
　以下の手順によって実施例に係る構造体を作製した。 (Example)
A structure according to an example was manufactured according to the following procedure.
　まず、逆共沈法によって原料粉末を合成した。具体的には、まず、１６．７ｍｍｏｌの塩化亜鉛（ＺｎＣｌ２）と３３．３ｍｍｏｌの塩化アルミニウム６水和物（ＡｌＣｌ３・６Ｈ２Ｏ）とを水に溶解し、１００ｍＬの混合水溶液を調製した。また、５０ｍｍｏｌの炭酸ナトリウム（Ｎａ２ＣＯ３）を水に溶解し、５０ｍＬの炭酸ナトリウム水溶液を調製した。５ｍｏｌ／Ｌの水酸化ナトリウム水溶液でｐＨを約１０に調製しながら、混合水溶液を炭酸ナトリウム水溶液に滴下した。得られた懸濁液を室温で２４時間撹拌した後、濾過し、残渣を１５０ｍＬの水で４回洗浄した。洗浄した残渣を７０℃で８時間乾燥して原料粉末を得た。 First, a raw material powder was synthesized by a reverse coprecipitation method. Specifically, first, 16.7 mmol of zinc chloride (ZnCl 2 ) and 33.3 mmol of aluminum chloride hexahydrate (AlCl 3 .6H 2 O) were dissolved in water to prepare 100 mL of a mixed aqueous solution. . Further, 50 mmol of sodium carbonate (Na 2 CO 3 ) was dissolved in water to prepare 50 mL of an aqueous sodium carbonate solution. The mixed aqueous solution was added dropwise to the sodium carbonate aqueous solution while adjusting the pH to about 10 with a 5 mol/L aqueous sodium hydroxide solution. The resulting suspension was stirred at room temperature for 24 hours, then filtered, and the residue was washed four times with 150 mL of water. The washed residue was dried at 70° C. for 8 hours to obtain a raw material powder.
　図３は、得られた原料粉末を３０００倍で観察したＳＥＭ像である。図４は、得られた原料粉末を１００００倍で観察したＳＥＭ像である。図３及び図４に示すように、原料粉末中の粒子径は不揃いでミクロンサイズであることが確認できた。 FIG. 3 is a SEM image of the obtained raw material powder observed at 3000x magnification. FIG. 4 is a SEM image of the obtained raw material powder observed at a magnification of 10,000 times. As shown in FIGS. 3 and 4, it was confirmed that the particle diameters in the raw material powder were irregular and micron-sized.
　図５は、得られた原料粉末のＸＲＤパターンを示すグラフである。図５に示すように、粉末のＸＲＤパターンには、［Ｚｎ２＋ ２／３Ａｌ３＋ １／３（ＯＨ）２］［ＣＯ３ ２－］１／６・２／３Ｈ２Ｏのピークが含まれることが確認できた。 FIG. 5 is a graph showing the XRD pattern of the obtained raw material powder. As shown in Figure 5, the XRD pattern of the powder includes the peaks of [Zn 2+ 2/3 Al 3+ 1/3 (OH) 2 ][CO 3 2- ] 1/6 ·2/3H 2 O. This was confirmed.
　図６は、得られた原料粉末をＡＴＲ法によって測定した赤外線スペクトルである。図６に示すように、赤外線スペクトルは、ヒドロキシ基（－ＯＨ）、水（Ｈ２Ｏ）、炭酸イオン（ＣＯ３ ２－）に由来する吸収ピークを有することが確認できた。 FIG. 6 shows an infrared spectrum of the obtained raw material powder measured by the ATR method. As shown in FIG. 6, it was confirmed that the infrared spectrum had absorption peaks derived from hydroxyl groups (-OH), water (H 2 O), and carbonate ions (CO 3 2- ).
　逆共沈法では、亜鉛イオンに対してアルミニウムイオンの量が２倍になるように混合水溶液を調製している。また、逆共沈法では、アルミニウムイオン及び亜鉛イオンが、ほぼ全量沈殿していた。そのため、［Ｚｎ２＋ ２／３Ａｌ３＋ １／３（ＯＨ）２］［ＣＯ３ ２－］１／６・２／３Ｈ２Ｏの生成に伴って生じた過剰のＡｌ３＋によって、非晶質のＡｌ（ＯＨ）３が生成されていると推定される。したがって、図３～図６の結果から、得られた原料粉末には、［Ｚｎ２＋ ２／３Ａｌ３＋ １／３（ＯＨ）２］［ＣＯ３ ２－］１／６・２／３Ｈ２Ｏの層状複水酸化物と非晶質のＡｌ（ＯＨ）３とが１：１のモル比で含まれていると考えられる。 In the reverse coprecipitation method, a mixed aqueous solution is prepared so that the amount of aluminum ions is twice that of zinc ions. Furthermore, in the reverse coprecipitation method, almost all of the aluminum ions and zinc ions were precipitated. Therefore , the amorphous _ _ _ _ _ _ It is estimated that Al(OH) 3 is generated. Therefore, from the results shown in FIGS. 3 to 6, the obtained raw material powder contains [Zn 2+ 2/3 Al 3+ 1/3 (OH) 2 ][CO 3 2- ] 1/6・2/3H 2 O It is thought that the layered double hydroxide and amorphous Al(OH) 3 are contained in a molar ratio of 1:1.
　次に、上記のようにして得られた原料粉末０．３ｇを、圧力４００ＭＰａかつ温度１８０℃の条件で３時間加熱及び加圧することによって構造体を作製した。 Next, a structure was produced by heating and pressurizing 0.3 g of the raw material powder obtained as described above at a pressure of 400 MPa and a temperature of 180° C. for 3 hours.
　図７は、Ｒｉｇａｋｕ社製のＸ線回折装置（ＭｉｎｉＦｌｅｘ）で測定して得られた構造体のＸＲＤパターンを示すグラフである。図７に示すように、構造体のＸＲＤパターンには、ＺｎＡｌ２Ｏ４のピークが含まれることが確認できた。また、構造体のＸＲＤパターンには、層状複水酸化物に由来するピークがほとんど見られなかった。このことから、層状複水酸化物からＺｎＡｌ２Ｏ４が生成されたことが分かる。また、解析ソフト（Ｒｉｇａｋｕ社製のＰＤＸＬ２）を用い、このＸＲＤパターンの２θ＝３６°のピークから結晶子サイズを測定したところ、結晶子サイズは３．５ｎｍであった。 FIG. 7 is a graph showing an XRD pattern of a structure obtained by measurement using an X-ray diffraction apparatus (MiniFlex) manufactured by Rigaku. As shown in FIG. 7, it was confirmed that the XRD pattern of the structure included a ZnAl 2 O 4 peak. Further, in the XRD pattern of the structure, almost no peaks derived from the layered double hydroxide were observed. This indicates that ZnAl 2 O 4 was generated from the layered double hydroxide. Further, when the crystallite size was measured from the peak at 2θ=36° of this XRD pattern using analysis software (PDXL2 manufactured by Rigaku), the crystallite size was 3.5 nm.
　図８は、得られた構造体をＡＴＲ法によって測定した赤外線スペクトルである。図８に示すように、赤外線スペクトルは、ヒドロキシ基（－ＯＨ）、水（Ｈ２Ｏ）、炭酸イオン（ＣＯ３ ２－）に由来する吸収ピークが原料粉末よりも小さくなることが確認できた。特に、層状複水酸化物の水（Ｈ２Ｏ）に由来するピークは、ほとんど消失していることが確認できた。 FIG. 8 shows an infrared spectrum of the obtained structure measured by the ATR method. As shown in Figure 8, the infrared spectrum confirmed that the absorption peaks derived from hydroxyl groups (-OH), water (H 2 O), and carbonate ions (CO 3 2- ) were smaller than those of the raw material powder. . In particular, it was confirmed that the peak derived from water (H 2 O) in the layered double hydroxide had almost disappeared.
　次に、実施例に係る構造体の全透過率及び直線透過率を島津製作所製の紫外可視分光光度計（ＵＶ－２６００）を用いて測定した。なお、全透過率の測定時には積分球を用いた。図９は、実施例に係る構造体の全透過率を示すグラフである。図１０は、実施例に係る構造体の直線透過率を示すグラフである。図９に示すように、実施例に係る構造体の全透過率は波長５５０ｎｍにおいて３６％であった。また、実施例に係る構造体の直線透過率は波長５５０ｎｍにおいて０．２４％であった。 Next, the total transmittance and in-line transmittance of the structure according to the example were measured using an ultraviolet-visible spectrophotometer (UV-2600) manufactured by Shimadzu Corporation. Note that an integrating sphere was used when measuring the total transmittance. FIG. 9 is a graph showing the total transmittance of the structure according to the example. FIG. 10 is a graph showing the in-line transmittance of the structure according to the example. As shown in FIG. 9, the total transmittance of the structure according to the example was 36% at a wavelength of 550 nm. Further, the in-line transmittance of the structure according to the example was 0.24% at a wavelength of 550 nm.
　上記のようにして得られた実施例に係る構造体の断面に、クロスセクションポリッシャー加工（ＣＰ加工）を施した。そして、走査型電子顕微鏡（ＳＥＭ）を用い、構造体の断面を観察した。実施例に係る構造体を１００００倍、３００００倍、２０００００倍及び１００００００倍に拡大したＳＥＭ像を図１１～図１４にそれぞれ示す。また、図１２のＳＥＭ像を二値化し、二値化した画像から気孔部分の面積割合を算出し、平均値を気孔率とした。この結果、実施例に係る構造体の気孔率は０．８％であることが分かった。構造体の気孔率が小さいため、気孔を起点として、構造体にひび割れが発生することが抑制されると考えられる。 Cross-section polisher processing (CP processing) was performed on the cross section of the structure according to the example obtained as described above. Then, the cross section of the structure was observed using a scanning electron microscope (SEM). SEM images of the structure according to the example magnified 10,000 times, 30,000 times, 200,000 times, and 1,000,000 times are shown in FIGS. 11 to 14, respectively. Further, the SEM image in FIG. 12 was binarized, the area ratio of the pores was calculated from the binarized image, and the average value was taken as the porosity. As a result, it was found that the porosity of the structure according to the example was 0.8%. Since the porosity of the structure is low, it is thought that cracks originating from the pores are suppressed from occurring in the structure.
　また、実施例の構造体の密度を測定したところ、密度は２．８６ｇ／ｃｍ３であり、ＺｎＡｌ２Ｏ４の密度（４．５ｇ／ｃｍ３）を基準とした場合の構造体の相対密度は６３．５％であった。気孔率が０．８％と実質的に０％であり、図７にＺｎＡｌ２Ｏ４以外のピークが確認できないことを考慮すると、構造体は非晶質の化合物を含んでいることが分かる。図８の赤外線スペクトル及び図示しない熱分析の結果などから、非晶質化合物は、亜鉛とアルミニウムとを含む水酸化物であると推定される。この水酸化物は、層状複水酸化物の一部が脱水して非晶質化したものであると推定される。 Furthermore, when the density of the structure of the example was measured, the density was 2.86 g/cm 3 , which is the relative density of the structure based on the density of ZnAl 2 O 4 (4.5 g/cm 3 ). was 63.5%. Considering that the porosity is 0.8%, which is essentially 0%, and that no peaks other than ZnAl 2 O 4 can be observed in FIG. 7, it can be seen that the structure contains an amorphous compound. From the infrared spectrum in FIG. 8 and the results of thermal analysis (not shown), it is estimated that the amorphous compound is a hydroxide containing zinc and aluminum. This hydroxide is presumed to be a part of the layered double hydroxide that has dehydrated and become amorphous.
　特願２０２２－０４３６９２号（出願日：２０２２年３月１８日）の全内容は、ここに援用される。 The entire contents of Japanese Patent Application No. 2022-043692 (filing date: March 18, 2022) are incorporated herein.
　以上、本実施形態を説明したが、本実施形態はこれらに限定されるものではなく、本実施形態の要旨の範囲内で種々の変形が可能である。 Although this embodiment has been described above, this embodiment is not limited to these, and various modifications can be made within the scope of the gist of this embodiment.
　本開示によれば、簡易な方法で作製することが可能であり、緻密で透光性を有する構造体及びその製造方法を提供することができる。 According to the present disclosure, it is possible to provide a structure that can be produced using a simple method, is dense and has translucency, and a method for manufacturing the structure.
　１　　構造体
　１０　結晶部
　２０　非晶質部 1 Structure 10 Crystal part 20 Amorphous part

Claims (6)

  1. 　ＺｎＡｌ２Ｏ４の結晶部と、
    　隣接する前記結晶部を結合し、亜鉛及びアルミニウムを有する非晶質化合物を含む非晶質部と、
    　を備え、
    　前記ＺｎＡｌ２Ｏ４の結晶子サイズは２０ｎｍ以下であり、
    　気孔率は２０％以下であり、
    　波長５５０ｎｍにおける全透過率は５％以上であり、
    　前記非晶質部はＳｉを実質的に含まない、構造体。     A crystal part of ZnAl 2 O 4 ,
    an amorphous part that combines the adjacent crystal parts and includes an amorphous compound containing zinc and aluminum;
    Equipped with
    The crystallite size of the ZnAl 2 O 4 is 20 nm or less,
    The porosity is 20% or less,
    The total transmittance at a wavelength of 550 nm is 5% or more,
    A structure in which the amorphous portion does not substantially contain Si.
  2. 　前記非晶質化合物はアルカリ金属元素、Ｂ、Ｖ、Ｔｅ、Ｐ、Ｂｉ及びＰｂを実質的に含まない、請求項１に記載の構造体。 The structure according to claim 1, wherein the amorphous compound is substantially free of alkali metal elements, B, V, Te, P, Bi, and Pb.
  3. 　前記非晶質化合物はＣａ、Ｓｒ及びＢａを実質的に含まない、請求項１又は２に記載の構造体。 The structure according to claim 1 or 2, wherein the amorphous compound is substantially free of Ca, Sr, and Ba.
  4. 　平均粒子径は１００ｎｍ以上の複数の無機粒子をさらに備える、請求項１～３のいずれか一項に記載の構造体。 The structure according to any one of claims 1 to 3, further comprising a plurality of inorganic particles having an average particle diameter of 100 nm or more.
  5. 　亜鉛とアルミニウムとを含む層状複水酸化物と、アルミニウムを含む水酸化物とを含む混合物を、圧力が１０～６００ＭＰａであり、かつ、温度が１００～３００℃である条件下で加圧及び加熱する工程を含む構造体の製造方法であって、
    　波長５５０ｎｍにおける前記構造体の全透過率は５％以上であり、
    　前記構造体は非晶質化合物を含む非晶質部を備え、
    　前記非晶質部はＳｉを実質的に含まない、構造体の製造方法。     A mixture containing a layered double hydroxide containing zinc and aluminum and a hydroxide containing aluminum is pressurized and heated at a pressure of 10 to 600 MPa and a temperature of 100 to 300°C. A method for manufacturing a structure, the method comprising:
    The total transmittance of the structure at a wavelength of 550 nm is 5% or more,
    The structure includes an amorphous portion containing an amorphous compound,
    A method for manufacturing a structure, wherein the amorphous portion does not substantially contain Si.
  6. 　前記混合物は平均粒子径が１００ｎｍ以上の複数の無機粒子をさらに含む、請求項５に記載の構造体の製造方法。 The method for manufacturing a structure according to claim 5, wherein the mixture further includes a plurality of inorganic particles having an average particle diameter of 100 nm or more.
PCT/JP2023/007613 2022-03-18 2023-03-01 Structure and method for manufacturing structure WO2023176453A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010024107A (en) * 2008-07-22 2010-02-04 Sumitomo Electric Ind Ltd Translucent ceramic
JP2010030820A (en) * 2008-07-28 2010-02-12 Sumitomo Electric Ind Ltd Translucent fused spinel
JP2011037641A (en) * 2009-08-06 2011-02-24 Sumitomo Electric Ind Ltd Method for producing translucent spinel ceramics structure and translucent spinel ceramics structure
JP2021505504A (en) * 2017-11-30 2021-02-18 コーニング インコーポレイテッド Ion-exchangeable transparent garnite-spinel glass ceramics with high hardness and elastic modulus

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010024107A (en) * 2008-07-22 2010-02-04 Sumitomo Electric Ind Ltd Translucent ceramic
JP2010030820A (en) * 2008-07-28 2010-02-12 Sumitomo Electric Ind Ltd Translucent fused spinel
JP2011037641A (en) * 2009-08-06 2011-02-24 Sumitomo Electric Ind Ltd Method for producing translucent spinel ceramics structure and translucent spinel ceramics structure
JP2021505504A (en) * 2017-11-30 2021-02-18 コーニング インコーポレイテッド Ion-exchangeable transparent garnite-spinel glass ceramics with high hardness and elastic modulus

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