WO2023176453A1 - Structure et procédé de fabrication de structure - Google Patents

Structure et procédé de fabrication de structure Download PDF

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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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English (en)
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/fr

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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

Cette structure (1) comprend : des parties cristallines (10) de ZnAl2O4 ; et une partie amorphe (20) qui lie les parties cristallines adjacentes (10) et contient un composé amorphe ayant du zinc et de l'aluminium. La taille de cristallite de ZnAl2O4 est d'au plus 20 nm, la porosité est d'au plus 20 %, la transmittance totale à une longueur d'onde de 550 nm est d'au moins 5 %, et la partie amorphe (20) ne contient sensiblement pas de Si.
PCT/JP2023/007613 2022-03-18 2023-03-01 Structure et procédé de fabrication de structure WO2023176453A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010024107A (ja) * 2008-07-22 2010-02-04 Sumitomo Electric Ind Ltd 透光性セラミックス
JP2010030820A (ja) * 2008-07-28 2010-02-12 Sumitomo Electric Ind Ltd 透光性電融スピネル
JP2011037641A (ja) * 2009-08-06 2011-02-24 Sumitomo Electric Ind Ltd 透光性スピネルセラミックス構造体の製造方法および透光性スピネルセラミックス構造体
JP2021505504A (ja) * 2017-11-30 2021-02-18 コーニング インコーポレイテッド 高い硬度および弾性率を有するイオン交換可能な透明ガーナイト−スピネル・ガラスセラミックス

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010024107A (ja) * 2008-07-22 2010-02-04 Sumitomo Electric Ind Ltd 透光性セラミックス
JP2010030820A (ja) * 2008-07-28 2010-02-12 Sumitomo Electric Ind Ltd 透光性電融スピネル
JP2011037641A (ja) * 2009-08-06 2011-02-24 Sumitomo Electric Ind Ltd 透光性スピネルセラミックス構造体の製造方法および透光性スピネルセラミックス構造体
JP2021505504A (ja) * 2017-11-30 2021-02-18 コーニング インコーポレイテッド 高い硬度および弾性率を有するイオン交換可能な透明ガーナイト−スピネル・ガラスセラミックス

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