Nitride powder, three-dimensional modeling composition, modeled object, sintered body, method for producing modeled object, and method for producing sintered body

Abstract

To provide a nitride powder that enables improvement of the modeling speed of a three-dimensional modeled object.SOLUTION: The nitride powder of the present invention is a nitride powder having a diffuse reflectance of 93.7% or more with respect to light of a wavelength of 405 nm, the nitride powder being a boron nitride powder.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a nitride powder, a composition for three-dimensional modeling, a shaped object, a sintered body, a method for manufacturing a shaped object, and a method for manufacturing a sintered body. More specifically, the present invention relates to a nitride powder, a composition for three-dimensional modeling containing the nitride powder, a method for manufacturing a composition for three-dimensional modeling, a shaped object comprising a hardened body of a composition for three-dimensional modeling, a sintered body of a shaped object, a method for manufacturing a shaped object, and a method for manufacturing a sintered body. [Background technology]

[0002] 2. Description of the Related Art Conventionally, one known method for producing a three-dimensional object is to laminate a pattern shape using a material for three-dimensional modeling. Also known is so-called stereolithography, in which a material formed into a three-dimensional shape by lamination or the like is cured by irradiating it with electromagnetic waves such as ultraviolet light. Examples of stereolithography methods include the SLA (Stereo Lithography Apparatus) method, in which a photocurable composition is irradiated with spot-shaped ultraviolet laser light to obtain a three-dimensional object, and the DLP (Digital Light Processing) method, in which a photocurable composition is irradiated with planar light to obtain a three-dimensional object.

[0003] For example, the particles described in Patent Document 1 (JP 2023-90120 A) are known to be used as raw materials for photocuring additive manufacturing objects. Patent Document 1 discloses the use of filler particles comprising black inorganic particles such as carbon as conductive particles and a white inorganic substance such as gadolinium-doped ceria particles that coat the surfaces of the black inorganic particles. Patent Document 1 discloses that black inorganic particles absorb light from a light source, making it impossible to uniformly photocur the entire molded object. However, Patent Document 1 discloses that providing a white inorganic substance on the surfaces of the black inorganic particles produces a powder for additive manufacturing suitable for manufacturing additive manufacturing objects using stereolithography. Furthermore, Patent Document 2 (JP 2017-119363 A) discloses a technology in which a powder containing a blend of ceramic powder and resin powder is used in a three-dimensional modeling apparatus to increase the initial strength of a three-dimensional object. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-90120 [Patent Document 2] Japanese Patent Application Publication No. 2017-119363 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, three-dimensional objects have been attracting increasing attention. However, the techniques described in Patent Documents 1 and 2 do not specifically consider the formability of three-dimensional objects when nitride powder is used as a raw material for the object. The reason for this is thought to be that conventional nitride powders tend to absorb light, which can lead to insufficient photocuring. Therefore, the present inventors focused on the issue of increasing the forming speed when nitride powder is used as a raw material for the three-dimensional object. [Means for solving the problem]

[0006] As a result of intensive research to solve the problem, the inventor discovered that the manufacturing speed of three-dimensional objects can be effectively increased by using the diffuse reflectance of nitride powder at a specific wavelength as an indicator and using nitride powder with a predetermined diffuse reflectance, and thus completed the present invention.

[0007] According to the present invention, the following nitride powder and related techniques are provided.

[0008] [1] Boron nitride powder with a diffuse reflectance of 93.7% or more for light with a wavelength of 405 nm. [2] Boron nitride powder with a diffuse reflectance of 93.0% or more for light with a wavelength of 355 nm. [3] Boron nitride powder with a diffuse reflectance of 86% or more for light with a wavelength of 300 nm. [4] Boron nitride powder with a diffuse reflectance of 70% or more for light with a wavelength of 250 nm. [5] Aluminum nitride powder with a diffuse reflectance of 73.5% or more for light with a wavelength of 405 nm. [6] Aluminum nitride powder with a diffuse reflectance of 71.5% or more for light with a wavelength of 355 nm. [7] Aluminum nitride powder with a diffuse reflectance of 69% or more for light with a wavelength of 300 nm. [8] Aluminum nitride powder with a diffuse reflectance of 39% or more for light with a wavelength of 250 nm. [9] The nitride powder according to any one of [1] to [8], which is used as a raw material for three-dimensional modeling.

[10] The nitride powder according to any one of [1] to [8], which is used as a raw material for stereolithography.

[11] The nitride powder according to any one of [1] to [8], which is used as a raw material for additive manufacturing.

[12] The nitride powder according to any one of [1] to

[11] , The nitride powder contains primary particles, and the particle size at 50% of the cumulative size (D50) determined by the volume-based particle size distribution measured by a particle size distribution measuring device using a laser diffraction / scattering method of the primary particles is 0.1 to 60 μm.

[13] The nitride powder according to any one of [1] to

[12] , Specific surface area is 0.1 to 20m 2 / g of nitride powder.

[14] A composition for three-dimensional modeling, comprising the nitride powder according to any one of [1] to

[13] .

[15] The composition for three-dimensional object formation according to

[14] , A composition for three-dimensional modeling, wherein the content of the nitride powder is 30 mass % or more based on the total amount of the powder.

[16] A method for producing a composition for three-dimensional object formation according to

[14] or

[15] , mixing the nitride powder with a powder other than the nitride powder; A method for producing a composition for three-dimensional modeling, wherein the content of the nitride powder is 30 mass % or more based on the total amount of the powder.

[17] A modeled object made from the composition for three-dimensional modeling according to

[14] or

[15] .

[18] A sintered compact of the shaped product according to

[17] .

[19] A method for manufacturing a shaped object according to

[17] , A method for manufacturing a three-dimensional object, comprising the step of forming a predetermined pattern shape using the composition for three-dimensional modeling to obtain a three-dimensional object.

[20] A method for manufacturing a shaped object according to

[19] , and hardening the composition for three-dimensional modeling in the predetermined pattern shape to obtain the model.

[21] A method for producing a shaped object according to

[19] or

[20] , The method for producing a three-dimensional object includes irradiating the composition for three-dimensional object with electromagnetic waves or electron beams to cure the composition, thereby obtaining the three-dimensional object.

[22] A method for manufacturing a shaped object according to any one of

[19] to

[21] , The method for manufacturing a shaped object includes repeatedly applying or coating and laminating the composition for three-dimensional modeling to form the predetermined pattern shape.

[23] A method for manufacturing a shaped object according to any one of

[19] to

[22] , A method for manufacturing a shaped object, further comprising the step of processing the shaped object.

[24] A method for manufacturing a shaped object according to any one of

[19] to

[23] , A method for producing a sintered body, comprising a step of sintering nitride powder at 1500°C or higher and 2500°C or lower.

[25] The nitride powder according to any one of [1] to

[13] , which is used for a sputtering target.

[26] The nitride powder according to any one of [1] to

[13] , which is used for fabricating a MEMS.

[27] The nitride powder according to any one of [1] to

[13] , which is used to prepare a SAW filter or a BAW filter.

[28] The nitride powder according to any one of [1] to

[13] , which is used to fabricate an electronic device. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a nitride powder and related technology that can improve the speed at which three-dimensional objects can be manufactured. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a UV irradiation test in an example. [Figure 2] FIG. 1 is a graph showing the relationship between the diffuse reflectance (%) and the treatment temperature (° C.) of the boron nitride powders of the examples and comparative examples. [Figure 3] FIG. 1 is a graph showing the relationship between the diffuse reflectance (%) at 405 nm and the thickness (mm) of the hardened region of the boron nitride powders of each of the Examples and Comparative Examples. [Figure 4] FIG. 1 is a graph showing the relationship between the diffuse reflectance (%) at 355 nm and the thickness (mm) of the hardened region of the boron nitride powders of each of the Examples and Comparative Examples. [Figure 5] FIG. 2 is a graph showing the relationship between diffuse reflectance (%) and wavelength (nm) for boron nitride powders of each example and comparative example. [Figure 6] FIG. 2 is a graph showing the relationship between the frequency (volume %) and particle size (μm) of boron nitride powders in each of the examples and comparative examples. [Figure 7] FIG. 1 is a diagram showing X-ray diffraction patterns of boron nitride powders of each of the examples and comparative examples. [Figure 8] 1 shows X-ray diffraction patterns of boron nitride powders of Examples and Comparative Examples. [Figure 9] FIG. 1 is a graph showing the relationship between the diffuse reflectance (%) and the treatment temperature (° C.) of the aluminum nitride powders of the examples and comparative examples. [Figure 10] FIG. 1 is a graph showing the relationship between the diffuse reflectance (%) at 405 nm and the thickness (mm) of the hardened region of the aluminum nitride powders of each of the Examples and Comparative Examples. [Figure 11] FIG. 1 is a graph showing the relationship between the diffuse reflectance (%) at 355 nm and the thickness (mm) of the hardened region of the aluminum nitride powders of each of the Examples and Comparative Examples. [Figure 12] FIG. 1 is a graph showing the relationship between diffuse reflectance (%) and wavelength (nm) for aluminum nitride powders of each of the examples and comparative examples. [Figure 13] FIG. 2 is a graph showing the relationship between the frequency (volume %) and particle size (μm) of aluminum nitride powders in each of the examples and comparative examples. [Figure 14] FIG. 1 is a diagram showing X-ray diffraction patterns of aluminum nitride powders of each of Examples and Comparative Examples. [Figure 15] FIG. 1 is a diagram showing X-ray diffraction patterns of aluminum nitride powders of each of Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail.

[0012] In this specification, the expression "a to b" in the description of a numerical range means from a to b, unless otherwise specified. For example, "1 to 5 mass%" means "1 mass% to 5 mass%." Furthermore, the lower limit and upper limit of a numerical range can be arbitrarily combined with the lower limit and upper limit of another numerical range.

[0013] Unless otherwise specified, each of the components and materials exemplified in this specification may be used alone or in combination of two or more.

[0014] The gas content (vol %) in this specification is a value under standard conditions (0° C., 1 atm).

[0015] 1. Nitride powder The nitride powder is a particle group including primary nitride particles, and may further include agglomerated particles (secondary particles) formed by agglomerating the primary nitride particles. Furthermore, the primary particles and aggregated particles in the nitride powder may have oxides such as aluminum oxide, boric acid, etc. on their surfaces. The purity of the nitrides such as aluminum nitride and boron nitride in the nitride powder may be 98% by mass or more, or may be 99% by mass or more.

[0016] The nitride powder is preferably one or more selected from aluminum nitride particles and boron nitride particles. These have higher thermal conductivity than other oxides and other substances, allowing for good shaping. Among these, boron nitride particles are preferred in terms of achieving high thermal conductivity. Aluminum nitride particles are also preferred because they provide higher thermal conductivity than silicon nitride and the mechanical strength of the sintered product is higher than that of boron nitride.

[0017] (diffuse reflectance) When the nitride powder of this embodiment is aluminum nitride, the diffuse reflectance for light with a wavelength of 405 nm is 73.5% or more, more preferably 74.5% or more, and preferably 78% or more. This allows electromagnetic waves irradiated onto the nitride powder to be efficiently reflected and diffused around the nitride powder. As a result, when the nitride powder is used as a material for stereolithography, the curability of the material for stereolithography can be improved, and the modeling speed can be increased. Furthermore, when the nitride powder is boron nitride, the diffuse reflectance for light with a wavelength of 405 nm is preferably 93.7% or more, and more preferably 95% or more. The upper limit of the diffuse reflectance of the nitride powder for light with a wavelength of 405 nm is not particularly limited, but may be, for example, 100% or less, or 99% or less. In addition, light with a wavelength of 405 nm is widely used as a laser for stereolithography, and acts efficiently on photopolymerization initiators in ultraviolet-curing resins, generating radicals and other polymerization factors to efficiently harden the material.

[0018] When the nitride powder of this embodiment is aluminum nitride, the diffuse reflectance for light with a wavelength of 355 nm is 71.5% or more, preferably 73% or more, and more preferably 77% or more. This allows electromagnetic waves irradiated onto the nitride powder to be efficiently reflected and diffused around the nitride powder. As a result, when the nitride powder is used as a material for stereolithography, the curability of the material for stereolithography can be improved, and the modeling speed can be increased. Furthermore, when the nitride powder is boron nitride, the diffuse reflectance for light with a wavelength of 355 nm is preferably 93% or more, and more preferably 96% or more.

[0019] When the nitride powder of this embodiment is aluminum nitride, the diffuse reflectance for light with a wavelength of 300 nm is 69% or more, preferably 75% or more, and more preferably 77% or more. This allows electromagnetic waves irradiated onto the nitride powder to be efficiently reflected and diffused around the nitride powder. As a result, when the nitride powder is used as a material for stereolithography, the curability of the material for stereolithography can be improved, and the modeling speed can be increased. Furthermore, when the nitride powder is boron nitride, the diffuse reflectance for light with a wavelength of 300 nm is 86% or more, preferably 90% or more, and more preferably 95% or more.

[0020] When the nitride powder of this embodiment is aluminum nitride, the diffuse reflectance for light with a wavelength of 250 nm is 39% or more, preferably 41% or more, and more preferably 43% or more. This allows electromagnetic waves irradiated onto the nitride powder to be efficiently reflected and diffused around the nitride powder. As a result, when the nitride powder is used as a material for stereolithography, the curability of the material for stereolithography can be improved, and the modeling speed can be increased. Furthermore, when the nitride powder is boron nitride, the diffuse reflectance for light with a wavelength of 250 nm is 70% or more, preferably 80% or more, and more preferably 90% or more.

[0021] The diffuse reflectance of the nitride powder can be measured using an ultraviolet-visible spectrophotometer equipped with an integrating sphere device.

[0022] Nitride powder having the above-described diffuse reflectance can be realized by using the manufacturing method described below. For example, it is possible to select the raw material of the nitride powder, or to use a conventional nitride powder as the raw material and subject it to a predetermined heat treatment. However, the manufacturing method of the nitride powder of this embodiment is not limited to this.

[0023] (particle size) The nitride powder of this embodiment preferably has a particle size at 90% of the cumulative total (D90) of 1 to 200 μm, more preferably 1 to 100 μm or less, and even more preferably 1 to 50 μm, as determined from the volume-based particle size distribution measured with a particle size distribution measuring device using a laser diffraction / scattering method for primary particles. The nitride powder of this embodiment preferably has a particle size at 50% of the cumulative total (D50) of 0.1 to 60 μm, more preferably 0.2 to 30 μm, and even more preferably 0.5 to 15 μm, as determined from the volume-based particle size distribution measured with a particle size distribution measuring device using a laser diffraction / scattering method for primary particles. The nitride powder of this embodiment preferably has a particle size (D10) at 10% cumulative volume determined from the volume-based particle size distribution measured with a particle size distribution analyzer using a laser diffraction / scattering method for primary particles of 0.1 to 10 μm, more preferably 0.2 to 8 μm or less, and even more preferably 0.3 to 5 μm. By setting the particle size within the above numerical range, it becomes easier to improve the modeling speed. Furthermore, by setting the particle size at or above the above lower limit, it becomes possible to control the viscosity low when mixed with resin, and set the viscosity to facilitate additive manufacturing. Furthermore, by setting the particle size at or below the above upper limit, it becomes possible to reduce the surface roughness during sintering. The particle size can be controlled by adjusting classification and pulverization conditions.

[0024] (specific surface area) The nitride powder of this embodiment has a specific surface area of ​​0.1 to 20 m 2 / g, and 0.2 to 10m 2 / g is more preferable, and 0.5 to 8m 2 / g is even more preferable. By setting the specific surface area to the above lower limit or more, sintering becomes easier. On the other hand, by setting the specific surface area to the above upper limit or less, the frequency with which irradiated light hits the silicon nitride during stereolithography decreases, the probability that irradiated light is absorbed by the silicon nitride decreases, the curing speed of the photocurable resin increases, and the modeling speed becomes easier to improve. Furthermore, by setting the specific surface area to the above upper limit or less, the viscosity does not increase too much when the silicon nitride is mixed with the resin, making it easier to laminate. The specific surface area, BET specific surface area, can be measured by the BET single-point method using nitrogen gas in accordance with JIS Z 8803:2013.

[0025] The specific surface area is controlled by the manufacturing conditions of the nitride powder. For example, it can be controlled to a low value by promoting sintering and particle growth through heat treatment, or to a high value by pulverizing using jet milling or ball milling. It can also be controlled to a low value by removing fine powder through classification, or to a high value by removing coarse powder. By controlling the specific surface area low, the viscosity can be controlled low when mixed with resin, making it possible to set a viscosity that is easy to use in additive manufacturing.

[0026] (Application) The nitride powder of this embodiment can be suitably used for various applications. For example, when used as a raw material for three-dimensional modeling, a modeled object having excellent mechanical properties can be obtained. Three-dimensional modeling can be performed by at least one method selected from additive manufacturing and stereolithography.

[0027] [Manufacturing method] Next, an example of a method for producing the nitride powder of this embodiment will be described. The method for producing the nitride powder of this embodiment is as follows: A step (step 1) of preparing a nitride powder material of a group III compound, a group IV compound, or a group V compound; and a step (step 2) of heat treating the nitride powder material at 500°C or higher and 2500°C or lower. In other words, by subjecting conventional nitride powder material to heat treatment at a temperature of 500°C or higher and 2500°C or lower, it is possible to obtain nitride powder that satisfies at least one of the following: a diffuse reflectance of 73.5% or higher for light with a wavelength of 405 nm, and a diffuse reflectance of 71.5% or higher for light with a wavelength of 355 nm. Each step will be described in detail below.

[0028] (Step 1) A step of preparing nitride powder material First, the nitride powder material is a powder containing nitride, and is a raw material for the nitride powder (A). The nitride powder material may be a commercially available product or one prepared by reaction, such as aluminum nitride powder (E grade manufactured by Tokuyama Corporation) or boron nitride powder (SP-2 manufactured by Denka Company Ltd.).

[0029] The following describes the preparation of boron nitride powder material and aluminum nitride powder material by reaction.

[0030] <Preparation of boron nitride powder material> In order to effectively obtain hexagonal boron nitride powder as one of the boron nitride powder raw materials, first, an oxygen-containing calcium compound, an oxygen-containing boron compound, and a carbon source are mixed as follows.

[0031] (oxygen-containing calcium compounds) The oxygen-containing calcium compound forms a composite oxide with the oxygen-containing boron compound, which serves as a grain growth catalyst for boron nitride particles. Examples of oxygen-containing calcium compounds include calcium carbonate, calcium bicarbonate, calcium hydroxide, calcium oxide, calcium nitrate, calcium sulfate, calcium phosphate, and calcium oxalate. Of these, oxygen-containing calcium compounds are preferably used. Examples of oxygen-containing calcium compounds that can be used include calcium carbonate, calcium bicarbonate, calcium hydroxide, calcium oxide, calcium nitrate, calcium sulfate, calcium phosphate, and calcium oxalate. Two or more of these compounds can also be used in combination. Of these, calcium oxide and calcium carbonate are preferably used. Two or more of the oxygen-containing calcium compounds can also be used in combination. The average particle size of the oxygen-containing calcium compound is preferably 0.01 to 200 μm, more preferably 0.05 to 120 μm, and particularly preferably 0.1 to 80 μm.

[0032] (carbon source) The carbon source acts as a reducing agent, and it is preferable to use one containing a specific amount of sulfur in order to ensure that sulfur contributes to the reaction. As the carbon source, a petroleum-derived carbon source that already contains sulfur is preferred. Although the sulfur can be added as elemental sulfur separately from the carbon source, it is preferable that the sulfur be in close proximity to the carbon source. In this case, it is preferable to premix the sulfur and the carbon source in advance, for example, using a ball mill. If the premixing is omitted, not only will the sulfur volatilize violently during the reaction, requiring the addition of a large amount, but there is also a risk of sulfur scattering into the exhaust system of the reactor, causing blockage. The concentration of sulfur contained in the carbon source is 1000 to 10000 ppm, preferably 1500 to 8000 ppm, and more preferably 2000 to 6000 ppm. The carbon source is preferably amorphous carbon, which has high reactivity, and carbon black is particularly preferred because it is industrially quality controlled.The average particle size of the carbon source is preferably 0.01 to 3 μm, more preferably 0.02 to 2 μm, and particularly preferably 0.05 to 1 μm.

[0033] (Preparation of raw materials) The reduction-nitridation reaction is carried out by supplying a carbon source and nitrogen, and in order to effectively obtain the desired hexagonal boron nitride powder, the ratio of B contained in the oxygen-containing boron compound and composite oxide to C contained in the carbon source, calculated as B / C (element ratio), is 0.75 to 0.85, preferably 0.77 to 0.83.

[0034] To effectively obtain the desired hexagonal boron nitride powder, the oxygen-containing calcium compound is mixed in a ratio of 10 to 15 parts by mass, calculated as CaO, for 100 parts by mass of the total amount of the oxygen-containing boron compound and the carbon source (calculated as B2O3 and C).

[0035] In the method for producing a boron nitride powder material, the form in which the mixture containing the above-mentioned raw materials is supplied to the reaction is not particularly limited; it may be in powder form or may be formed into granules. To mix the raw materials, a common mixer such as a vibration mill, bead mill, ball mill, Henschel mixer, drum mixer, vibration agitator, or V-shaped mixer can be used. For granulation, a binder can be used as needed, and known methods such as extrusion granulation, rolling granulation, and compactor granulation can be used. In this case, the size of the granules is preferably about 5 to 10 mm.

[0036] (reduction nitridation) In the method for producing a boron nitride powder material, the nitrogen source can be supplied to the reaction system by known means. For example, the most preferred method is to circulate nitrogen gas through the reaction system of the reactor illustrated below. The nitrogen source to be used is not limited to the nitrogen gas described above, and any gas capable of nitriding in the reduction-nitridation reaction can be used. Specifically, ammonia gas can be used in addition to the nitrogen gas described above. A mixed gas obtained by mixing nitrogen gas or ammonia gas with a non-oxidizing gas such as hydrogen, argon, or helium can also be used.

[0037] To obtain hexagonal boron nitride powder, it is important to heat the reaction at 1450-1550°C for at least 4 hours and at 1650-2100°C for at least 2 hours. That is, heating for at least 4 hours in the temperature range of 1450-1550°C, where the reduction-nitridation reaction begins, facilitates layering of the hexagonal crystal planes, enabling the highly selective production of hexagonal boron nitride particles with a high amount of NH groups on the particle edge faces and a low aspect ratio. Temperatures below 1450°C are undesirably slow, while temperatures above 1550°C are undesirably too fast. Furthermore, temperatures less than 4 hours are undesirable due to the insufficient reaction time. Furthermore, to obtain highly crystalline hexagonal boron nitride particles, the maximum heating temperature for the reduction-nitridation reaction is 1650-2100°C, preferably 1700-2100°C, and more preferably 1800-2000°C, for at least 2 hours.

[0038] The method for producing hexagonal boron nitride powder can be carried out using a known reaction apparatus capable of controlling the reaction atmosphere, such as an atmosphere-controlled high-temperature furnace in which heat treatment is performed by high-frequency induction heating or heater heating, or a batch furnace or a continuous furnace such as a pusher-type tunnel furnace or a vertical reactor.

[0039] (acid washing) The reaction product obtained by the above-mentioned reduction nitridation contains impurities such as a composite oxide of boron oxide and calcium oxide in addition to the hexagonal boron nitride powder, so it is preferable to wash it with an acid. The acid washing method is not particularly limited, and known methods can be used without limitation. For example, the by-product-containing boron nitride obtained after the nitriding treatment is crushed and placed in a container, and dilute hydrochloric acid (10 to 20% by mass HCl) is added in an amount 5 to 10 times the amount of the impurity-containing hexagonal boron nitride powder, and the mixture is allowed to contact for at least 4 hours. In addition to hydrochloric acid, other acids such as nitric acid, sulfuric acid, and acetic acid can also be used in the acid washing. After the acid washing, the product is washed with pure water to remove any remaining acid. One method for washing the product is to filter the acid used in the acid washing, disperse the acid-washed boron nitride in pure water in an amount equal to the amount of acid used, and then filter again.

[0040] (Dry) The conditions for drying the hydrous aggregates after the acid washing and water washing are preferably, for example, drying in the air or under reduced pressure at 50 to 250° C. The drying time is not particularly specified, but it is preferable to dry until the moisture content approaches 0%.

[0041] (classification) The dried boron nitride powder may be subjected to rough crushing, removal of coarse particles using a sieve or the like, and removal of fine particles using air classification or the like, as required.

[0042] <Preparation of aluminum nitride powder material> Aluminum nitride powder material can be obtained by heat treating boehmite powder in a non-oxidizing atmosphere containing ammonia (NH3) or by mixing it with a carbon-containing substance.

[0043] Examples of the ammonia (NH3)-containing non-oxidizing atmosphere include an ammonia (NH3) gas atmosphere, or an ammonia (NH3) and nitrogen (N2) mixed gas atmosphere in which the ammonia (NH3) content is 70 volume % or more but less than 100 volume %, with the remainder being nitrogen (N2). In the case of an ammonia (NH3) and nitrogen (N2) mixed gas, the ammonia (NH3) content is more preferably 75 to 95 volume %. The heat treatment temperature at which the AlN production reaction proceeds can be 1200 to 1600°C, and more preferably 1300 to 1550°C.

[0044] The heat treatment can be carried out by placing the raw material powder in a furnace with an air-tight structure, maintaining the furnace atmosphere in a predetermined ammonia-containing non-oxidizing atmosphere, and raising the temperature of the powder in the furnace to the predetermined range. The pressure in the furnace may be atmospheric pressure. During the heat treatment, in order to maintain the atmospheric gas composition in the furnace within a constant range, it is desirable to pass an externally supplied ammonia-containing gas through the furnace and expose the powder to the gas flow. The powder is desirably placed in the furnace in as thin a state as possible so that individual particles can easily come into contact with the atmospheric gas components. For example, if the powder is deposited on a tray and the tray is placed in the furnace, the thickness of the powder deposited on the tray is preferably 5 mm or less.

[0045] The above heat treatment time is sufficient to convert all of the raw material boehmite powder placed in the furnace into aluminum nitride (AlN). The required firing time varies depending on the specific surface area of ​​the raw material powder, the heating temperature, the atmospheric gas composition, and the deposition state of the powder placed in the furnace. For example, if the BET specific surface area is 180 to 300 m, 2 When boehmite powder of about 1 / g is heated to 1200 to 1600°C in a non-oxidizing atmosphere with an ammonia (NH3) content of 70 to 100% by volume, an appropriate heating time can usually be set within the range of 2 to 10 hours, more preferably within the range of 4 to 8 hours.

[0046] (Step 2) Heat treatment Next, the nitride powder is heat-treated at 400°C or higher and 2500°C or lower. Specifically, the nitride powder material is heat-treated at 400°C or higher and 2500°C or lower while controlling the atmosphere, packing density, and pressure in the pot. This improves the diffuse reflectance of the nitride powder. It is believed that controlling the atmosphere, packing density, pressure, and temperature in the pot reduces defects caused by nitrogen vacancies and oxygen intrusion and solid solution, thereby reducing excess light absorption. Heating from room temperature to 100°C or higher, preferably 400°C or higher, and more preferably 800°C or higher while evacuating the furnace removes moisture adsorbed on the nitride powder and moisture desorbed from water of crystallization (OH groups). Gas is then introduced, reducing impurities such as moisture in the atmosphere and enabling efficient removal of defects in the nitride powder. The heat treatment temperature is 400 to 2500°C, preferably 1000 to 2300°C, and more preferably 1500 to 2000°C. The heat treatment temperature is preferably 1650 to 2000°C, more preferably 1700 to 2000°C, from the viewpoint of reducing the internal oxygen content, and is preferably 1500 to 1800°C, more preferably 1500 to 1700°C, from the viewpoint of reducing nitrogen defects and increasing diffuse reflectance. The heat treatment temperature may also be set depending on the type of nitride. For example, in the case of silicon nitride, the temperature is preferably 1600 to 1800°C, in the case of boron nitride, the temperature is preferably 1600 to 1800°C, and in the case of aluminum nitride, the temperature is preferably 1400 to 1600°C. By setting the heat treatment temperature at or above the lower limit, the diffuse reflectance can be increased and the molding speed can be improved. On the other hand, by setting the heat treatment temperature at or above the upper limit, good diffuse reflectance can be obtained while improving the moldability of the nitride powder. Furthermore, the heat treatment may be performed by holding the temperature during the temperature rise, or by adjusting the temperature rise rate or cooling rate. By holding the temperature during the temperature rise or slowing the temperature rise rate, moisture adsorbed on the nitride powder and water of crystallization (OH groups) are released, and the resulting moisture is volatilized in the low-temperature region and discharged outside the furnace, and then the heat treatment can be performed at the specified temperature in an atmosphere with few impurities. The temperature to be held during the temperature rise is preferably 600°C, 800°C, 1000°C, 1200°C, 1400°C, or temperatures around these temperatures. The holding time is preferably around 2 hours, 6 hours, 12 hours, or 36 hours. The temperature rise rate may be 10°C / min, 1°C / min, or 0.1°C / min or less. Furthermore, by increasing the cooling rate, the time during which the nitride powder is exposed to a temperature range where defects are likely to be generated can be reduced. The cooling rate may be 1°C / min, 10°C / min, 100°C / min or more. It is preferable to start the heat treatment at a temperature of 50°C or below.

[0047] Furthermore, pressure may be applied during the heat treatment, preferably under a pressure of 0.001 to 100 MPaG, more preferably under a pressure of 0.005 to 10 MPaG, and even more preferably under a pressure of 0.020 to 1 MPaG. By setting the pressure during the heat treatment to be equal to or greater than the lower limit, the diffuse reflectance can be increased, whereas by setting the pressure during the heat treatment to be equal to or greater than the upper limit, the nitride powder can be molded with good formability while still obtaining good diffuse reflectance. For example, it is preferable that the heat treatment is carried out in a vacuum of 100 Pa or less from the start of heating until the temperature reaches 800°C, and then in a gas atmosphere at 800°C or higher.

[0048] Furthermore, the heat treatment is preferably carried out in an inert gas, a reducing gas, or under vacuum, i.e., by introducing a predetermined gas into a furnace. Examples of inert gases include rare gas elements such as helium, neon, and argon, as well as nitrogen gas, etc. Examples of reducing gases include chlorine gas, hydrogen sulfide gas, ammonia gas, sulfur oxide gas, hydrogen gas, and nitrogen oxide gas, etc. The flow rate of the gas introduced into the furnace relative to the volume of the furnace is A (L / min), and the volume of the furnace is B (m 3 ), by setting A / B > 5, the gas generated from the nitride powder (A) can be efficiently discharged outside the furnace, reducing impurities in the atmosphere and efficiently removing defects in the nitride powder (A). (Gas flow rate (L / min)) ÷ (Furnace volume (m 3 ))(A / B) is preferably 10 or more, and more preferably 20 or more. It is also preferable to discharge the gas so that the pressure inside the furnace is kept constant.

[0049] For example, the nitride powder material is put into a furnace and heating is started, the internal pressure of the furnace is set to 50 Pa or less at temperatures below 100°C, and gas is introduced at temperatures above 100°C, and the flow rate (L / min) of the gas introduced into the furnace is set to the volume (m 3 ) is preferably adjusted to 5 or more. That is, from the start of heating until the temperature reaches at least 100°C, it is preferable to keep the internal pressure in the furnace at 50 Pa or less by vacuum treatment, and the internal pressure in the furnace after reaching 100°C may be 50 Pa or less or may exceed 50 Pa. Furthermore, as long as the temperature is 100°C or higher, gas may be introduced at any time; for example, gas may be introduced once the temperature reaches 1000°C. In addition, it is preferable to start the heat treatment at a temperature of 50° C. or less.

[0050] The heat treatment is preferably carried out by filling a container with the nitride powder material. Examples of the container include ceramics such as boron nitride and silicon nitride, and metals such as tungsten and molybdenum. The pot (container) for the nitride powder is preferably made of boron nitride, which has a relatively low density, in order to efficiently volatilize gases generated from the nitride powder. The amount of the nitride powder material (a) to be filled is adjusted appropriately, but for example, the bulk density is set to 0.3 to 1.6 g / cm 3 It may be 1.14 g / cm 3 It is preferable to do the following: By setting the amount of nitride powder filled in the pot (container) to the above upper limit or less, gas generated from the nitride powder can be efficiently volatilized to the outside of the pot (container).

[0051] The resulting nitride powder may also be pulverized. The pulverization may be carried out in multiple stages, including coarse pulverization and fine pulverization. The pulverization may be carried out wet using, for example, a ball mill. When the specific surface area of ​​the fired product is 3.0 to 15.0 m, 2 It may be ground to a concentration of 1 / g. The time for the pulverization treatment (pulverization time) in the ball mill pulverization step may be 5 to 15 hours, or 8 to 12 hours, which makes it possible to sufficiently finely disintegrate aggregated particles while preventing excessive pulverization.

[0052] The pulverized product obtained in the ball mill pulverization step may be further pulverized in a vibration mill pulverization step. The ball filling rate in the container in the vibration mill pulverization step may be 50 to 80 volume % or 60 to 75 volume %. The pulverization time in the vibration mill pulverization step (pulverization time) may be 8 to 20 hours or 12 to 17 hours.

[0053] Furthermore, in order to adjust the particle size of the pulverized material, classification may be carried out using a sieve, for example, a sieve with openings of 20 to 350 μm.

[0054] When using a wet ball mill or wet jet mill, a filtration or drying process may be performed. Filtration may be performed by vacuuming to separate the solvent, or by applying gas or mechanical pressure to the slurry to push the solvent out of the filter paper or filter. Natural drying, heat drying, or vacuum and heat drying may also be used. Before drying, the nitride powder may be allowed to settle using centrifugal force, and the supernatant may be removed before drying. Alternatively, an acid or alkali may be used to adjust the isoelectric point and promote sedimentation, and the supernatant may be removed before drying.

[0055] The obtained nitride powder may be subjected to rough crushing, removal of coarse particles by sieving or the like, and removal of fine particles by air classification or the like, as required.

[0056] By such a production method, the nitride powder of this embodiment can be obtained.

[0057] 2. Composition for three-dimensional modeling The composition for three-dimensional modeling according to the present embodiment contains the nitride powder described above, which can improve the modeling speed using the composition for three-dimensional modeling. The composition for three-dimensional modeling may be a mixture of a nitride powder and other powders, or may further contain a curable resin as described below. The composition for three-dimensional modeling may be in the form of a powder or a paste.

[0058] (nitride powder) The content of the nitride powder in the total amount of the composition for three-dimensional modeling can be adjusted appropriately depending on the application. For example, when a photocurable resin is used, the content of the nitride powder is preferably 5 to 100% by mass, more preferably 40 to 60% by mass, in order to obtain good photocurability. Furthermore, when a photocurable resin is not used, the content of the nitride powder in the total amount of the composition for three-dimensional modeling may be 90% by mass or more, 99% by mass or more, or even 100% by mass. This reduces the work required to remove the resin residue. Furthermore, different types of nitride powders may be mixed and used. That is, by combining nitrides in a way that compensates for the different advantages and disadvantages of each type, it is possible to further improve the desired balance of performance. For example, a composite material may be made by combining boron nitride, which has relatively high thermal conductivity, with aluminum nitride or silicon carbide powder, which has relatively high mechanical strength when sintered. The nitride powder of this embodiment may be a mixture of nitride powder with a small particle size obtained by pulverization or the like and nitride powder with a large particle size. By using nitride powder with a small particle size in part, sintering during three-dimensional modeling can be more easily promoted.

[0059] (curable resin) The composition for three-dimensional modeling of this embodiment may contain a curable resin. This provides appropriate viscosity, making it easier to form complex or dense patterns with high precision. Furthermore, since the curable resin is subsequently burned off by firing, the sintered body of the model can have high strength.

[0060] The curable resin may be one or more selected from photocurable resins, thermosetting resins, and photo- and thermosetting resins. Specifically, known resins such as acrylic resins and epoxy resins can be used, with acrylic resins being preferred. For example, when a photocurable resin is included, the content of the photocurable resin is relatively preferably 10 to 90 mass %, more preferably 20 to 80 mass %, more preferably 30 to 70 mass %, and even more preferably 40 to 60 mass %, relative to the total amount of the composition for three-dimensional modeling.

[0061] (others) In addition, the composition for three-dimensional modeling may contain known additives, such as powders other than the nitride powders mentioned above, adhesives, bonding resins, thermosetting resins, dispersants, photopolymerization initiators, ultraviolet absorbers, pigments, and other known materials.

[0062] The powders other than the nitride powder may be either inorganic or organic, and examples thereof include inorganic powders such as conventionally known nitride powders, metal particles, and ceramic particles; and organic powders. More specifically, the above-mentioned conventionally known nitride powder is intended to mean one whose diffuse reflectance does not satisfy a predetermined value and which has not been subjected to a heat treatment in advance at a temperature of 1500° C. or more and 2500° C. or less. In other words, it is a nitride powder that does not satisfy either a diffuse reflectance of 73.5% or more for light with a wavelength of 405 nm or a diffuse reflectance of 71.5% or more for light with a wavelength of 355 nm. For example, the composition for three-dimensional modeling of this embodiment may contain a mixture containing a conventionally known nitride powder in addition to the nitride powder of this embodiment. Because the conventionally known nitride powder has not been subjected to a heat treatment at 1500°C or higher and 2500°C or lower in advance, the inclusion of the conventionally known nitride powder can promote sintering after three-dimensional modeling. Furthermore, from the viewpoint of promoting sintering, it is preferable that the conventionally known nitride powder have a small particle size and a large specific surface area.

[0063] Examples of the ceramic particles include powders of glass such as silica glass (quartz glass) and soda-lime silica glass; metal oxides such as zirconia, alumina, and mullite (aluminosilicate minerals); metal carbides such as silicon carbide and tungsten carbide; and metal nitrides such as aluminum nitride. When the composition for three-dimensional modeling contains the above powder, the content of the nitride powder relative to the total amount of powder is relatively preferably 40% by mass or more, preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 95% by mass or more, particularly preferably 99.9% by mass or more, and most preferably 100% by mass. For example, the content of the conventionally known nitride powder may be 5 to 50 mass% of the total amount of powder, preferably 30 mass% or more in order to obtain good hardenability, and more preferably 40 mass% or more in order to further enhance hardenability.

[0064] The adhesive (such as a binding resin or a thermosetting resin) is preferably used when the three-dimensional modeling composition does not contain a curable resin. That is, the nitride powder can be shaped using the adhesive (such as a binding resin or a thermosetting resin). Specifically, for example, the nitride powder may be applied, and then the adhesive may be sprayed repeatedly to stack the nitride powder and shape the resulting object. As the adhesive (such as a binding resin or a thermosetting resin), any known adhesive for use in three-dimensional modeling compositions can be used.

[0065] (viscosity) The viscosity (25° C.) of the composition for three-dimensional modeling is preferably 100 Pa·s to 150,000 Pa·s in terms of ejection properties and pattern shape formability. The viscosity can be measured using a rheometer ("MCR-300" manufactured by Nippon SiberHegner KK) under the following conditions. Conditions: Plate shape: 25mm diameter, sample thickness: 1mm, temperature: 25±1℃, shear rate: 0.1S -1

[0066] 3. Modeled objects The object of the present embodiment is made of a three-dimensional modeling composition and is obtained by forming a predetermined pattern shape using the above-mentioned composition for three-dimensional modeling. Because the object of the present embodiment uses the above-mentioned composition for three-dimensional modeling, it has an excellent modeling speed and good productivity. The method for producing the shaped object is not particularly limited, and any known method can be used, but it is preferable to select an appropriate method depending on the composition and application of the composition for three-dimensional modeling.

[0067] For example, the method for manufacturing a shaped object preferably includes the steps of forming a predetermined pattern shape using the above-described composition for three-dimensional modeling, and curing the composition for three-dimensional modeling to obtain a cured body.

[0068] The curing method is preferably determined depending on the composition and application of the composition for three-dimensional modeling. For example, when the composition for three-dimensional modeling contains a photocurable resin or a photo- and thermosetting resin, it is preferable to cure the resin by irradiating it with electromagnetic waves or electron beams. Examples of electromagnetic waves include ultraviolet rays, visible light, infrared rays, and microwaves. Among these, ultraviolet rays are preferred. Furthermore, when the composition for three-dimensional modeling contains a thermosetting resin, it may be cured by heating. The three-dimensional modeling composition may also be cured by drying. Alternatively, an adhesive (such as a bonding resin or a thermosetting resin) may be locally applied to the composition for three-dimensional modeling, and the composition may be cured using a modeling method (binder jet type).

[0069] Alternatively, the sintered layers may be stacked and molded by repeatedly applying the composition for three-dimensional modeling and sintering the nitride powder. In this case, the curing step can be omitted. Sintering is performed in the same manner as for the sintered body described below.

[0070] Furthermore, the method for forming the predetermined pattern shape is not particularly limited and any known method can be used, but it is preferable to repeatedly apply or coat the composition for three-dimensional modeling to form layers and then laminate the layers. The composition for three-dimensional modeling may be in any form of powder, paste, liquid, or gas.

[0071] 4. Sintered body The sintered body of this embodiment is obtained by sintering a shaped object. The method for producing a sintered body includes a step of sintering the shaped object obtained by the method for producing a shaped object at 1500 to 2500°C. This sinters the nitride powder, resulting in excellent strength. Furthermore, if the composition for three-dimensional modeling contains a curable resin, a debinding treatment is performed at approximately 400 to 800°C before sintering to remove the resin component.

[0072] The nitride powder of this embodiment can be suitably used for sputtering targets and in the production of electronic devices such as MEMS, SAW filters, and BAW filters. High purity (low levels of impurities other than the target substance) is important for sputtering targets and electronic devices such as MEMS, SAW filters, and BAW filters. The heat treatment of this embodiment can reduce the amount of components volatilized during the heat treatment. Furthermore, particle growth during the heat treatment reduces the proportion of adsorbed substances and oxide layers present on the nitride surface relative to the total volume of the nitride. This reduces the proportion of adsorbed substances and oxide layers relative to the total volume of the nitride, thereby increasing the purity of the nitride. Furthermore, during the heat treatment, heterogeneous phases and dissolved elements present inside the nitride, such as dissolved oxygen impurities and metal impurities of other elements, are expelled from the nitride and volatilized and removed, thereby increasing the purity of the nitride. For example, the nitride powder can also be used for sputtering targets containing AlN, BN, AlScN, or the nitrides listed above.

[0073] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted. [Example]

[0074] Next, the present invention will be described in detail with reference to examples, but the content of the present invention is not limited to the examples.

[0075] (1) Measurement of diffuse reflectance The diffuse reflectance was measured using an ultraviolet-visible spectrophotometer (V-650) manufactured by JASCO Corporation equipped with an integrating sphere device (ISV-722). Baseline correction was performed using a standard reflector (Spectralon), and a solid sample holder filled with silicon nitride powder (a quartz cell filled with silicon nitride powder and tapped 20 times) was set in place, and diffuse reflectance was measured in the wavelength range of 220 to 850 nm. The measurement parameters were set as follows: response: Medium, bandwidth: 2.0 nm, scan speed: 200 nm / min, data acquisition interval: 0.5 nm, scan mode: Continuous, control settings: Baseline correction, switching wavelength: 340 nm, light source: "Automatic," and filter switching: "Stop scan." Diffuse reflectance (%) was measured at wavelengths of 250 nm, 300 nm, 355 nm, 405 nm, 500 nm, 600 nm, 700 nm, and 800 nm. The results are shown in Table 2 and Figures 2-5, 9-12. In Figures 3, 4, 10, and 11, the results for each example and comparative example are plotted on a graph with the thickness (mm) of the cured region (cured part) (described below) on the vertical axis and the diffuse reflectance (%) on the horizontal axis.

[0076] (2) Measurement of particle size [Boron nitride] The particle size of boron nitride was measured using a Microtrac MT3300EXII (Microtrac Bell Corporation), a particle size measuring device that uses the laser diffraction and scattering method, in accordance with the method described in JIS Z 8825:2013, "Particle size analysis - Laser diffraction and scattering method." The measurement procedure was as follows: First, 60 mg of boron nitride was weighed into a 500 mL container. This was mixed with 2 mL of a 20% aqueous solution of sodium hexametaphosphate as a dispersant and 200 g of water. Next, the mixture was mixed and dispersed for 3 minutes using an ultrasonic homogenizer (manufactured by Nippon Seiki Seisakusho, product name: US-300) to obtain a measurement sample. The particle size of this measurement sample was measured using the MT3300EII. Pure water was used as the solvent for the Microtrac circulator. This pure water was used to adjust the concentration of boron nitride in the measurement sample. From the particle size distribution of the obtained boron nitride, the particle sizes (unit: μm) of D10, which is the particle size at 10% of the cumulative volume from the small particle size side, D50, which is the particle size at 50% of the cumulative volume from the small particle size side, and D90, which is the particle size at 90% of the cumulative volume from the small particle size side were calculated. The results are shown in Table 2 and Figure 13.

[0077] [Aluminum nitride] The particle size of the nitride powder (aluminum nitride) was measured using a Microtrac MT3300EXII (Microtrac Bell Corporation), a particle size measuring device that uses the laser diffraction and scattering method. The measurement procedure involved adding 0.5 g of the nitride powder (aluminum nitride) to be measured to 100 ml of ion-exchanged water containing 0.05 wt% sodium hexametaphosphate. The sample was dispersed for 3 minutes using an ultrasonic homogenizer (Ultrasonic Homogenizer US-150E, Nippon Seiki Seisakusho Co., Ltd.) at 100% amplitude, 19.5 ± 1 kHz frequency, 20 mm tip diameter, and 32 ± 2 μm amplitude. The tip was placed in the center of the solution and the dispersion was then measured using the MT3300EII. The particle size distribution of the resulting nitride powder (aluminum nitride) was used to determine the particle sizes (units: μm) of D10, which represents the 10% cumulative volume of the smallest particle size, D50, which represents the 50% cumulative volume of the smallest particle size, and D90, which represents the 90% cumulative volume of the smallest particle size. The results are shown in Table 2 and Figure 6.

[0078] (3) Measurement of specific surface area The BET specific surface area V of the nitride powder was measured by the BET single-point method using nitrogen gas in accordance with JIS Z 8803:2013 "Method for measuring the specific surface area of ​​powders (solids) by gas adsorption." The results are shown in Table 2.

[0079] (4) Measurement of total oxygen and nitrogen content Oxygen and nitrogen were measured using an oxygen and nitrogen analyzer (EMGA-920 (HORIBA)). The results are shown in Table 2.

[0080] (5) Quantitative determination of crystalline phase X-ray diffraction of nitride powder was performed using an X-ray diffractometer (Bruker, D8 ADVANCE, 18kW) with a LynxEye detector, a scanning speed of 0.017° / 0.5 sec, CuKa radiation, and a rotating sample stage. Quantitative analysis was performed using Rietveld analysis using the software TOPAS. The results are shown in Table 3 and Figures 7-8, 14-15.

[0081] (6) Measurement of impurity content The impurity contents of the nitride powder were measured by the following procedure. The impurities were dissolved by the pressure acid decomposition method to prepare a sample solution. The obtained sample solution was subjected to quantitative elemental analysis using an ICP optical emission spectrometer (manufactured by Rigaku Corporation, product name: CIROS-120). The carbon and sulfur contents were measured using a CS-444LS manufactured by LECO. The results are shown in Table 3.

[0082] (7) Preparation of nitride powder (7-1) Boron nitride powder <Examples 1 and 2> First, "SP-2" manufactured by Denka was prepared as the raw material boron nitride powder, and heat-treated under the test conditions shown in Table 1 to obtain boron nitride powders for the examples and comparative examples. The conditions not listed in Table 1 are as follows: 200 g of boron nitride powder material was weighed into a cylindrical boron nitride container with a lid (a molded product made by Denka Co., Ltd., mainly composed of boron nitride (product name: Denka Boron Nitride N-1), inner diameter: 10 cm, height: 10 cm). The weight of the boron nitride powder material relative to the volume of the container was 0.5 g / cm. 3The weight of the boron nitride powder material relative to the volume in the container was set to below 1000°C. If the weight of the boron nitride powder material relative to the volume in the container is too high, sintering of the boron nitride powder material will proceed, which will hinder an increase in diffuse reflectance, so this was taken into consideration. Furthermore, if the weight of the nitride powder relative to the volume in the container is too high, the components volatilizing from the boron nitride powder material will be less likely to escape from the container, so the weight of the nitride powder in the container was controlled as above. The container was then placed in an electric furnace equipped with a carbon heater, and the pressure was reduced to 6 Pa or less. While evacuating with a vacuum pump, the temperature was raised to 1000°C in a vacuum state. Once above 1000°C, nitrogen gas was introduced, and the temperature was raised to the temperature specified in Table 1 in a nitrogen gas atmosphere (pressure: 0.025 MPaG). Heating was performed at the set temperature in Table 1 for 4 hours (heat treatment I). After introducing nitrogen gas, the gas flow rate (L / min) introduced into the furnace was calculated by dividing the furnace volume (m 3 ) was set to 33, and the introduction and discharge of gas was controlled to maintain a constant pressure. This was done to expel volatile components from the raw boron nitride powder material outside the furnace and to prevent the volatiles from affecting the boron nitride powder material. After heating, the sample that had become loosely agglomerated in the container was placed in a mortar and crushed. After crushing, the sample was passed through a sieve with 250 μm openings to obtain a powdered sintered body (boron nitride powder; BN). The obtained boron nitride powder was subjected to the above measurements (1) to (6). The results are shown in Tables 1 to 3.

[0083] <Examples 3 and 4> The same treatment as in Example 1 was carried out except that Ar gas was introduced during heat treatment I, treatment was carried out in an Ar gas atmosphere, and treatment temperatures were set at the temperatures shown in Table 1.

[0084] <Example 5> The boron nitride powder obtained in Example 2 was further pulverized in ethanol using a ball mill using zirconia balls with a diameter of 5 mm, filtered, dried, and passed through a sieve with 250 μm openings.

[0085] <Comparative Example 1> The boron nitride powder material was used as is to carry out the measurements (1) to (6) above.

[0086] <Comparative Example 2> During heat treatment I, a container filled with boron nitride powder was placed in an electric furnace equipped with a carbon heater, and the furnace was evacuated to a pressure of 6 Pa or less. Ar gas was then introduced at room temperature, and the temperature was raised to the temperature shown in Table 1 under an Ar gas atmosphere (pressure: 0.025 MPaG). Heating was then carried out at the temperature shown in Table 1 for 4 hours. After the introduction of Ar gas, the gas flow rate (L / min) introduced into the furnace was calculated as follows: 3 ) was set to 4, and the same treatment as in Examples 1 to 4 was carried out except that the introduction and discharge of gas were controlled so as to keep the pressure constant.

[0087] (8-2) Aluminum nitride powder <Examples 6 and 7> First, E grade aluminum nitride powder (manufactured by Tokuyama Corporation) was prepared as a raw material, and heat-treated under the test conditions shown in Table 1 to obtain each aluminum nitride powder. The conditions not listed in Table 1 are as follows: 200 g of aluminum nitride powder material was weighed into a cylindrical boron nitride container with a lid (a molded product made by Denka Co., Ltd., mainly composed of boron nitride (product name: Denka Boron Nitride N-1), inner diameter: 10 cm, height: 10 cm). The weight of the aluminum nitride powder material relative to the volume of the container was 0.5 g / cm. 3 The weight of the aluminum nitride powder material relative to the volume in the container was set to the following. If the weight of the aluminum nitride powder material relative to the volume in the container is too high, sintering of the aluminum nitride powder material will proceed, which will hinder an increase in diffuse reflectance, so this was taken into consideration. Furthermore, if the weight of the nitride powder relative to the volume in the container is too high, the components volatilizing from the aluminum nitride powder material will be less likely to escape from the container, so the weight of the nitride powder in the container was controlled as above. Thereafter, this container was placed in an electric furnace equipped with a carbon heater, and the pressure was evacuated to 6 Pa or less. While evacuating with a vacuum pump, the temperature was raised to 1000°C in a vacuum state. When the temperature was above 1000°C, nitrogen gas was introduced, and the temperature was raised to the temperature conditions in Table 1 under a nitrogen gas atmosphere (pressure: 0.025 MPaG), and heating was carried out at the set temperature in Table 1 for 4 hours (heat treatment I). After introducing nitrogen gas, the gas flow rate (L / min) introduced into the furnace divided by the furnace volume (m 3) was set to 33, and the introduction and discharge of gas was controlled to maintain a constant pressure. This was done to expel volatile components from the raw aluminum nitride powder material outside the furnace and to prevent the aluminum nitride powder material from being affected by the volatiles. After heating, the sample that had become loosely agglomerated in the container was placed in a mortar and crushed. After crushing, the sample was passed through a sieve with 250 μm openings to obtain a powdered sintered body (aluminum nitride powder; AlN). The aluminum nitride powder thus obtained was subjected to the above measurements (1) to (6). The results are shown in Tables 1 to 3.

[0088] Example 8 The same treatment as in Example 6 was carried out except that Ar gas was introduced during heat treatment I and treatment was carried out in an Ar gas atmosphere.

[0089] <Comparative Example 3> The aluminum nitride powder material was used as it was, and the above measurements (1) to (6) were carried out.

[0090] <Comparative Example 4> During heat treatment I, a container filled with aluminum nitride powder was placed in an electric furnace equipped with a carbon heater, and the furnace was evacuated to 6 Pa or less. Nitrogen gas was then introduced at room temperature, and the temperature was raised to the temperature shown in Table 1 under a nitrogen gas atmosphere (pressure: 0.025 MPaG). Heating was then carried out at the temperature shown in Table 1 for 4 hours. After introducing nitrogen gas, the gas flow rate (L / min) introduced into the furnace was divided by the furnace volume (m 3 ) was set to 4, and the same treatment as in Examples 6 to 8 was carried out except that the introduction and discharge of gas were controlled so as to keep the pressure constant.

[0091] (8) Evaluation 0.5 g of the obtained nitride powder was weighed out in the case of boron nitride, and 1.0 g in the case of aluminum nitride, and 2.5 g of photocurable resin (containing methacrylate monomer, product name Standard Photopolymer Resin Translucent, manufactured by ELEGOO, irradiation light 405 nm, viscosity (25°C) 150-200 mPa·s, UV-curable resin used in resin 3D printers was used to evaluate the curing speed during stereolithography of nitride powder) was mixed using a mixer (THINKY ARV-310, manufactured by Thinky Corporation) until homogeneous, to produce a paste-like composition for three-dimensional modeling. A polyethylene terephthalate (PET) film (250 μm thick) and a silicone sheet (1 mm thick) were placed on a glass plate (5 mm thick), and a paste-like three-dimensional modeling composition was poured into a 13 mm square opening that had been pre-made in the silicone sheet.The top surface was scraped off with a spatula to prepare a sample.

[0092] FIG. 1 is a diagram showing a schematic diagram of the UV irradiation test setup. As shown in FIG. 1, a frame-shaped boron nitride substrate 42 (15 mm thick) was placed on the top surface of a workbench 43, with a UV irradiator 41 installed on top. The prepared sample was placed on the top surface of the workbench 43 within the frame of the boron nitride substrate 42, and UV irradiation was performed using the UV irradiator 41 (2 minutes for the boron nitride-based samples (Examples 1 to 5, Comparative Examples 1 and 2), and 51 minutes for the aluminum nitride-based samples (Examples 6 and 7, Comparative Examples 3 and 4)) to harden the three-dimensional modeling composition. The UV irradiator 41 used was a "BOX-S3000" manufactured by Sanhayato Corporation. The cured product was then removed from the sample silicone sheet, and the thickness (depth) of the cured region (cured part) near the center of the irradiated surface of the cured product was measured. The thicker (deeper) the cured region, the faster the modeling speed. The results are shown in Table 1. The thickness (depth) of the cured region near the center of the irradiated surface of the cured product was measured after cutting or splitting the cured product near the center.

[0093] [Table 1]

[0094] [Table 2]

[0095] [Table 3] [Explanation of symbols]

[0096] 41 UV irradiation machine 42 Boron nitride substrate 43 Workbench

Claims

1. A nitride powder having a diffuse reflectance of 93.7% or more for light with a wavelength of 405 nm, The nitride powder is boron nitride powder.

2. A nitride powder having a diffuse reflectance of 93.0% or more for light with a wavelength of 355 nm, The nitride powder is boron nitride powder.

3. A nitride powder having a diffuse reflectance of 86% or more for light with a wavelength of 300 nm, The nitride powder is boron nitride powder.

4. A nitride powder having a diffuse reflectance of 70% or more for light with a wavelength of 250 nm, The nitride powder is boron nitride powder.

5. A nitride powder having a diffuse reflectance of 73.5% or more for light with a wavelength of 405 nm, The nitride powder is an aluminum nitride powder.

6. A nitride powder having a diffuse reflectance of 71.5% or more for light with a wavelength of 355 nm, The nitride powder is an aluminum nitride powder.

7. A nitride powder having a diffuse reflectance of 69% or more for light with a wavelength of 300 nm, The nitride powder is an aluminum nitride powder.

8. A nitride powder having a diffuse reflectance of 39% or more for light with a wavelength of 250 nm, The nitride powder is an aluminum nitride powder.

9. The nitride powder according to any one of claims 1 to 8, which is used as a raw material for three-dimensional modeling.

10. The nitride powder according to any one of claims 1 to 8, which is used as a raw material for stereolithography.

11. The nitride powder according to any one of claims 1 to 8, which is used as a raw material for additive manufacturing.

12. 9. The nitride powder according to claim 1, The nitride powder contains primary particles, and the particle size at 50% of the cumulative particle size (D50) determined from a volume-based particle size distribution measured by a particle size distribution measuring device using a laser diffraction / scattering method of the primary particles is 0.1 to 60 μm.

13. 9. The nitride powder according to claim 1, Specific surface area is 0.1 to 20 m ２ / g of nitride powder.

14. A composition for three-dimensional modeling, comprising the nitride powder according to claim 1 .

15. The composition for three-dimensional formation according to claim 14, A composition for three-dimensional modeling, wherein the content of the nitride powder is 30 mass% or more based on the total amount of the powder.

16. A method for producing the composition for three-dimensional formation according to claim 14, mixing the nitride powder with a powder other than the nitride powder; The content of the nitride powder is 30 mass% or more relative to the total amount of the powder.

17. A modeled object made from the composition for three-dimensional modeling according to claim 14.

18. A sintered compact of the shaped article according to claim 17.

19. The method for manufacturing a shaped object according to claim 17, A method for manufacturing a three-dimensional object, comprising the step of forming a predetermined pattern shape using the composition for three-dimensional modeling to obtain a three-dimensional object.

20. The method for manufacturing a shaped object according to claim 19, and hardening the composition for three-dimensional modeling in the predetermined pattern shape to obtain the model.

21. The method for manufacturing a shaped object according to claim 19, The method for producing a three-dimensional object includes irradiating the composition for three-dimensional object with electromagnetic waves or electron beams to cure the composition, thereby obtaining the three-dimensional object.

22. The method for manufacturing a shaped object according to claim 19, The method for manufacturing a shaped object includes repeatedly applying or coating and laminating the composition for three-dimensional modeling to form the predetermined pattern shape.

23. The method for manufacturing a shaped object according to claim 19, A method for manufacturing a shaped object, further comprising the step of processing the shaped object.

24. The method for manufacturing a shaped object according to claim 19, A method for producing a sintered body, comprising a step of sintering nitride powder at 1500°C or higher and 2500°C or lower.

25. 9. The nitride powder according to claim 1, which is used in a sputtering target.

26. 9. The nitride powder according to any one of claims 1 to 8, which is used to make MEMS.

27. 9. The nitride powder according to any one of claims 1 to 8, which is used to make a SAW filter or a BAW filter.

28. 9. The nitride powder of any one of claims 1 to 8, wherein the nitride powder is used to fabricate an electronic device.

Images