Powder for ceramic molding, method for producing ceramic molded article, ceramic structure, and apparatus

Abstract

The invention relates to a powder for ceramic molding, a method for manufacturing a ceramic molded article, a ceramic structure, and an apparatus. In order to provide a technique advantageous in manufacturing a ceramic structure having high mechanical strength and chemical resistance and crack repair properties using an additive manufacturing method, provided is a powder for ceramic molding, which contains one or more types of oxide particles, in which the powder contains at least Al, Y and Si, and wherein the powder has an elemental ratio Y / Si of Y to Si satisfying 25 / 75 < = Y / Si < = 95 / 5.

Description

Technical Field

[0001] This disclosure relates to a ceramic forming powder and a method for manufacturing ceramic molded articles using the powder, as well as ceramic structures, wherein the ceramic forming powder is applicable to additive manufacturing methods involving forming articles by additive manufacturing technology. Background Technology

[0002] In recent years, additive manufacturing technology, which involves adding materials to obtain desired structures based on three-dimensional data of a model to be manufactured, has gained wider use in applications such as rapid prototyping and small-batch production. In the manufacture of metal articles, direct manufacturing systems are widely employed, where metal powder is solidified and shaped by irradiating it with a laser, based on three-dimensional data of a model. According to this method, dense and diverse articles can be obtained by effectively melting and solidifying metal powder.

[0003] In Japanese Patent Application Publication No. 2019-19051, excellent forming accuracy is achieved by adding a rare earth oxide with a higher absorption capacity for infrared laser wavelengths than Al2O3 as an absorber to Al2O3 powder to suppress light diffusion. In Japanese Patent Application Publication No. 2023-72682, the cost of the powder used as a raw material is reduced by using SiO as an absorber.

[0004] In the molded articles disclosed in Japanese Patent Application Publication No. 2019-19051, fine cracks that appear during molding need to be repaired by impregnation. However, in impregnation repair, especially in molded articles with complex shapes, the impregnating liquid is not uniformly distributed, and areas that cannot be adequately repaired or have uneven composition appear. Therefore, problems such as reduced strength or cracking may occur.

[0005] Japanese Patent Application Publication No. 2023-72682 discloses a molded article containing a large amount of silica component, which has potential for improving mechanical properties and chemical resistance. Summary of the Invention

[0006] In view of the foregoing, this disclosure relates to an advantageous technique for manufacturing ceramic structures with high mechanical strength, chemical resistance, and crack repairability using additive manufacturing methods.

[0007] To address the aforementioned problems, a first aspect is a ceramic forming powder comprising one or more oxide particles, wherein the powder comprises at least Al, Y, and Si, and wherein the powder has an elemental ratio of Y to Si satisfying 25 / 75≤Y / Si≤95 / 5.

[0008] The second aspect is a method for manufacturing a ceramic molded article, comprising heating a material using ceramic forming powder with light to form the article, said ceramic forming powder comprising at least Al, Y and Si, and having an elemental ratio Y / Si satisfying 25 / 75≤Y / Si≤95 / 5, wherein at least one oxide particle is melted by heating.

[0009] In addition, the third aspect is a ceramic structure comprising Al, Y and Si, wherein the ceramic structure has an elemental ratio of Y to Si satisfying 25 / 75≤Y / Si≤95 / 5.

[0010] Additionally, an application example includes an apparatus comprising: the aforementioned ceramic molded article; and at least one of electrical components, optical components, metal components, or resin components.

[0011] The features of this disclosure will become apparent from the following description of the embodiments with reference to the accompanying drawings. The following description of the embodiments is given by way of example. Attached Figure Description

[0012] Figure 1A This is a schematic cross-sectional view illustrating a portion of the steps in one embodiment of a method for manufacturing shaped articles using a powder bed fusion system.

[0013] Figure 1B This is a schematic cross-sectional view illustrating a portion of the steps in one embodiment of a method for manufacturing shaped articles using a powder bed fusion system.

[0014] Figure 1C This is a schematic cross-sectional view illustrating a portion of the steps in one embodiment of a method for manufacturing shaped articles using a powder bed fusion system.

[0015] Figure 1D This is a schematic cross-sectional view illustrating a portion of the steps in one embodiment of a method for manufacturing shaped articles using a powder bed fusion system.

[0016] Figure 1E This is a schematic cross-sectional view illustrating a portion of the steps in one embodiment of a method for manufacturing shaped articles using a powder bed fusion system.

[0017] Figure 1F This is a schematic cross-sectional view illustrating a portion of the steps in one embodiment of a method for manufacturing shaped articles using a powder bed fusion system.

[0018] Figure 1GThis is a schematic cross-sectional view illustrating a portion of the steps in one embodiment of a method for manufacturing shaped articles using a powder bed fusion system.

[0019] Figure 1H This is a schematic cross-sectional view illustrating a portion of the steps in one embodiment of a method for manufacturing shaped articles using a powder bed fusion system.

[0020] Figure 2 This is a schematic cross-sectional view illustrating one embodiment of a method for manufacturing shaped articles using a cladding system.

[0021] Figure 3A The table shows the composition of the molding powders for the examples and comparative examples in mole fraction.

[0022] Figure 3B This is a table showing the composition of the molding powders for the examples and comparative examples by mass fraction.

[0023] Figure 3C This is a table showing the particle size and angle of repose of the forming powders for the embodiments and comparative examples.

[0024] Figure 3D-1 and Figure 3D-2 This is a table showing the elemental ratios and molar ratios of oxides in the forming powders of the embodiments and comparative examples.

[0025] Figure 3E This is a table showing the results of the embodiments and comparative examples.

[0026] Figure 4A These are SEM images of examples of various embodiments of the structure disclosed herein, and elemental mapping images of Al, Y, Si, and O evaluated according to SEM-EDX.

[0027] Figure 4B These are SEM images of examples of various embodiments of the structure disclosed herein, and elemental mapping images of Al, Y, Zr, Si, and O evaluated according to SEM-EDX. Detailed Implementation

[0028] The embodiments of this disclosure are described below with reference to the accompanying drawings. However, this disclosure is by no means limited to the specific examples or drawings below.

[0029] As used herein, aluminum oxide is sometimes described as aluminum oxide or Al₂O₃, yttrium oxide is sometimes described as Y₂O₃, silicon monoxide is sometimes described as SiO, silicon dioxide is sometimes described as silicon dioxide, silicon oxide, or SiO₂, and zirconium oxide is sometimes described as zirconia or ZrO₂. Each substance may have multiple crystalline structures or may be amorphous. Furthermore, the inclusion of other impurities, such as partial inclusion of oxygen or nitrogen, is not excluded.

[0030] In this embodiment, the percentage of the amount of substance (mol) of each compound relative to the total amount of substance (mol) of all compounds in a unit mass (e.g., 10 g) of powder is defined as the mole fraction (mol%).

[0031] Furthermore, for example, the terms "SiO-containing particles" or "silicon monoxide-containing particles" refer to particles that each contain SiO and are independent of each other, and the terms "SiO particles" or "silicon monoxide particles" refer to particles that are mainly formed of SiO and are independent of each other. As used herein, the term "mainly" means 50 mol% or more, preferably 75 mol% or more, more preferably 90 mol% or more. Both SiO particles and silicon monoxide particles contain 50 mol% or more of SiO, preferably 75 mol% or more, more preferably 90 mol% or more. This also applies to Al₂O₃ and Y₂O₃. <Powder for Ceramic Forming>

[0032] According to one embodiment of this disclosure, a powder for ceramic forming is provided. The term "powder for ceramic forming" is sometimes referred to below as "powder for ceramic forming" or "forming powder".

[0033] The forming powder of this embodiment is applicable to technologies known as direct manufacturing systems (especially powder bed fusion systems or infrared laser melting systems).

[0034] The forming powder of this embodiment (hereinafter also referred to as "material powder", "raw material powder" or simply "powder") comprises multiple independent particles, is suitable for additive manufacturing methods involving forming by laser irradiation, and mainly comprises more than one type of oxide particles. These particles can be classified into various types or can be formed from a large number of particles having uniform shape or material.

[0035] The forming powder of this embodiment comprises more than one type of oxide particles, and the oxide particles comprise at least Al, Y, and Si. Furthermore, the powder is characterized by having an elemental ratio of Y to Si satisfying 25 / 75 ≤ Y / Si ≤ 95 / 5. With this configuration, cracks in the intermediate formed article can self-repair upon heating.

[0036] When the Y / Si ratio is below 25 / 75, the mechanical strength, particularly the three-point flexural strength, of the desired ceramic structure (ceramic molded article) cannot be sufficiently improved. Y / Si is preferably 25 / 75 or higher because the ceramic structure (ceramic molded article) obtained in this embodiment satisfies the mechanical strength requirement, particularly a three-point flexural strength of 50 MPa or higher. A three-point flexural strength of 100 MPa or higher is more preferred, still more preferred is 150 MPa or higher, and very preferred is 170 MPa or higher. The three-point flexural strength can also be set to 200 MPa or higher. The three-point flexural strength can be 1,000 MPa or lower, 500 MPa or lower, or 400 MPa or lower. Furthermore, when the Y / Si ratio is too low, the chemical resistance, particularly the alkali resistance, of the desired ceramic structure cannot be sufficiently improved. Y / Si is preferably 25 / 75 or higher so that the mass change per unit area of ​​the desired ceramic structure is set to 100 g / m². 2 The desired change in mass per unit area of ​​the ceramic structure is more preferably 50 g / m². 2 The following is still more preferably 10g / m 2 The following is even more preferred: 5g / m 2 The alkali resistance of the ceramic structure to be obtained can be determined according to, for example, JIS R1614.

[0037] Furthermore, the density of the ceramic structure to be obtained is preferably 4.00 g / cm³. 3 The following applies when the density of the ceramic structure is 4.00 g / cm³. 3 At that time, it could be said that ceramic structures are light enough.

[0038] In the forming powder of this embodiment, the Y / Si ratio can satisfy Y / Si≥0.43, Y / Si≥0.50, more preferably Y / Si≥1.0, and still more preferably Y / Si≥2.0. When Y / Si equals 2.0, the ratios of Y2O3 and SiO2, calculated as oxides, become equivalent.

[0039] Furthermore, when the Y / Si ratio is too high, the self-healing crack property of the ceramic structure to be obtained in this embodiment cannot be adequately maintained. Preferably, the Y / Si ratio is 95 / 5 or lower in order to maintain the self-healing crack property of the ceramic structure, and further, to ensure that the function as a laser absorber is fully obtained when Si is contained as SiO.

[0040] Y / Si preferably satisfies Y / Si≤10.0, more preferably Y / Si≤9.0, and still more preferably Y / Si≤4.9. Y / Si≤4.0 or Y / Si≤3.0 can also be satisfied.

[0041] In addition, regarding the mole fraction, the powder for forming in this embodiment preferably satisfies at least one of the following conditions: the content of Al is higher than the content of Y; or the content of Al is higher than the content of Si.

[0042] The Si contained in the forming powder of this embodiment is preferably contained as an oxide of Si, that is, preferably as SiO or SiO2. Furthermore, Si is preferably contained as oxide particles, that is, preferably as silicon oxide particles. Silicon oxide particles include SiO particles (silicon monoxide particles), SiO2 particles (silicon dioxide particles or silicon oxide particles), SiO-containing particles (silicon monoxide-containing particles), SiO2-containing particles (silicon dioxide-containing particles or silicon oxide-containing particles), mixtures of any two of these particles, and mixtures of SiO particles and SiO2 particles.

[0043] Furthermore, the Al contained in the forming powder according to this embodiment is preferably contained as an Al oxide, that is, preferably as Al2O3. The forming powder preferably contains particles each containing an Al oxide, more preferably containing particles containing Al2O3 (alumina particles) or Al2O3 particles (alumina particles) as oxide particles. The particle size of each particle other than silicon oxide particles is preferably 10 μm or more and 200 μm or less, more preferably 10 μm or more and 50 μm or less.

[0044] The forming powder of this embodiment preferably contains 50 mol% or more of Al, based on oxides. This composition further improves the mechanical strength and chemical resistance of the ceramic structure. More preferably, the forming powder contains 60 mol% or more of Al; even more preferably, it contains 70 mol% or more of Al; and still even more preferably, it contains 80 mol% or more of Al.

[0045] Furthermore, the forming powder of this embodiment preferably contains Zr, and more preferably contains Zr as ZrO2. In addition, the forming powder preferably contains particles of oxides each containing Zr, and more preferably contains particles containing ZrO2 (zirconia particles) or ZrO2 particles (zirconia particles) as oxide particles.

[0046] This configuration further enhances the mechanical strength of the ceramic structure. The composition of the forming powder, based on oxides, more preferably contains 3 mol% or more of Zr, and even more preferably contains 7 mol% or more of Zr.

[0047] Regarding the mole fraction, the forming powder of this embodiment preferably satisfies at least one of the following conditions: the Al content is higher than the Zr content; the Y content is higher than the Zr content; or the Zr content is higher than the Si content. However, the mole fraction of Zr may be higher than the mole fraction of Al.

[0048] Furthermore, when the molding powder of this embodiment contains Y, Y is preferably contained as Y2O3. In addition, the molding powder preferably contains particles of oxides each containing Y, and more preferably contains particles containing Y2O3 (particles containing yttrium oxide) or Y2O3 particles (yttrium oxide particles) as oxide particles.

[0049] The indication of compounds such as Al₂O₃, Y₂O₃, SiO, or SiO₂ does not limit the composition of the indicated stoichiometric ratio and allows for an error in the constituent element ratio within ±30% of the stoichiometric ratio standardized by the metal elements. For example, compounds with a constituent element ratio of Si:O = 100:130 are also covered by the indication of SiO. That is, SiO can be represented as SiO₂. m (0.7≤m≤1.3).

[0050] The forming powder of this embodiment comprises one or more oxide particles, preferably Al2O3 particles and silicon oxide particles as oxide particles. The silicon oxide particles include SiO particles, SiO2 particles, or a mixture of SiO particles and SiO2 particles. Furthermore, the forming powder of this embodiment preferably comprises Y2O3 particles. Additionally, the forming powder of this embodiment preferably comprises ZrO2 particles. Each ZrO2 particle may contain Y.

[0051] As described above, the forming powder of this embodiment may contain particles other than silicon oxide particles. These particles may be, for example, Al₂O₃ particles, Y₂O₃ particles, or ZrO₂ particles. From the viewpoint of achieving preferred flowability, the average particle size of the particles other than silicon oxide particles may be 5 μm or more. The average particle size of the oxide particles other than silicon oxide particles is preferably 10 μm or more and 200 μm or less. The average particle size of the oxide particles other than silicon oxide particles may, for example, be 20 μm or more. The average particle size of the oxide particles other than silicon oxide particles may be 100 μm or less, 50 μm or less, or 40 μm or less. The average particle size of the oxide particles other than silicon oxide particles is preferably 10 μm or more and 50 μm or less, more preferably 20 μm or more and 40 μm or less.

[0052] The forming powder of this embodiment preferably contains particles with high absorption capacity for light (laser) at the wavelength irradiated during forming, and particularly preferably contains particles containing SiO. SiO appears brown or black and has a relatively high light absorption capacity for laser compared to Al2O3 or Y2O3 contained in the forming powder. When SiO absorbs laser light, the form of Si changes from divalent to tetravalent, changing from the metastable state of SiO to the more stable state of SiO2, thereby having a lower light absorption capacity for laser light. When forming is performed using powder in which SiO with such properties is added as an absorber to Al2O3 or Y2O3, the following effects and benefits can be obtained.

[0053] The primary function and effect is that SiO, acting as an absorber, increases its temperature by effectively absorbing the laser light used during manufacturing, thereby transferring heat to any other compounds present in the region corresponding to the focal point size of the laser, resulting in a temperature increase. As a result, localized heating corresponding to the focal point size of the laser can be effectively achieved, and the interface between the area where the powder is to be solidified (the area irradiated by the laser) and the area where the powder will not solidify (the area not yet irradiated by the laser) can be clearly defined, thereby improving forming accuracy.

[0054] The second function and effect is that SiO is transformed into SiO2 and the like with low light absorption capacity by laser irradiation, and light absorption is suppressed in the part where the powder is solidified after laser irradiation (the solidified part). x When the light absorption capacity of SiO decreases to less than 5 / 6 times that of SiO before laser irradiation, the cured portion will not be affected by reduced forming accuracy even when irradiated with a laser under the same conditions as during the curing of the cured portion. That is, there is almost no SiO acting as an absorber in the cured portion. Therefore, even when the cured portion is irradiated with a laser, the temperature rise as in the case before irradiation will not occur. Furthermore, even when the powder adjacent to the cured portion is irradiated with a laser, deformation and alteration of the cured portion are suppressed. As a result, process allowances such as laser irradiation conditions can be increased, and the influence of fluctuations in irradiation conditions on forming accuracy can be reduced. To obtain sufficient forming accuracy, the light absorption capacity of the individual SiO before laser irradiation is preferably more than 1.2 times, and more preferably more than 2 times, that of the absorber whose composition has changed after laser irradiation.

[0055] As described above, when the powder disclosed herein is selectively irradiated with a laser for forming, the aforementioned first and second effects are achieved, thus enabling high-precision forming. Furthermore, SiO is commercially available as a negative electrode for lithium-ion secondary batteries, and therefore can be purchased at a lower cost compared to any other compound that can be used as an absorber.

[0056] However, at least a portion of the SiO can be replaced by SiO2, or SiO can be replaced by SiO2 when heated, for example, by means other than laser. Additionally, TiO or the like can replace SiO as the absorber. In such cases, the powder may contain SiO2, and the Si used to evaluate the Y / Si ratio may be derived from SiO2. Optionally, the powder may contain elemental silicon or silicon compounds other than silicon oxides (e.g., silicon nitrides, silicon carbides, or metal silicides), and the Si used to evaluate the Y / Si ratio may be derived from such silicon compounds other than silicon oxides.

[0057] The individual particles contained in the forming powder may each be composite particles, such as a sintered body of multiple particles (sintered particles), and may be amorphous or crystalline. In this embodiment, the case where the powder is formed from multiple compounds includes the case of a mixture of multiple particles each formed from one compound, and the case of a single particle or a mixture of multiple particles each formed from multiple compounds. To avoid confusion, the individual particles contained in the powder are referred to as "particles" below, and the particles used to form individual particles are referred to as "constituent particles" below. For example, when sintering Al2O3 particles and Y2O3 particles to form composite particles, it can be said that the particles include constituent particles of Al2O3 and constituent particles of Y2O3. Alternatively, it can be said that each particle includes an Al2O3 region and a Y2O3 region.

[0058] As an example where each particle used to form the molding powder contains a compound, in the case of molding powder containing Al, Y and Si as elements, a state is given, for example, in which the molding powder is configured as a mixture of the three particles (i.e., Al2O3 particles, Y2O3 particles and SiO particles).

[0059] As an example, each of the particles used to form the molding powder contains multiple compounds, for example, a state in which one particle contains an Al2O3 region, a Y2O3 region and a SiO region, and a state in which the particles formed from each of the free Al2O3 region and the Y2O3 region and the particles formed from each of the free SiO region are given.

[0060] In powder bed fusion where a powder bed is formed using a recoater, or in cladding methods where powder is sprayed from a nozzle, it is important that the forming powder has suitable flowability. Therefore, the forming powder of this embodiment preferably satisfies a flowability index of 40 [seconds / 50g] or less. To ensure such flowability, each particle is preferably spherical. However, the shape of the particles is not limited to spherical, as long as the above flowability index is met. The flowability index can be measured, for example, according to JIS Z2502. Additionally, the angle of repose can be used as a flowability index. The forming powder of this embodiment preferably satisfies an angle of repose of 40° or less. The angle of repose can be measured according to JIS R9301-2-2.

[0061] The SiO2 that functions as an absorber is preferably contained in the powder for forming, wherein such SiO2-containing particles constitute 50 mol% or more of the particles, regardless of the state in which other compounds are contained. When 50 mol% or more of the particles are SiO2, particles that individually contain SiO2 and other compounds can function as absorbers.

[0062] Furthermore, SiO, which acts as an absorber, is particularly preferably contained in the forming powder as particles (SiO particles) independent of any other component, regardless of the state in which other compounds are contained therein.

[0063] Compared to the state where SiO is contained within a single particle along with other compounds, SiO achieves higher light absorption when it exists as independent SiO particles. Furthermore, the laser beam can easily reach the absorber, allowing for efficient utilization of its light absorption capacity. Moreover, when SiO acts as independent of other components, the particle size of the SiO particles and the particle sizes of the other particles can be adjusted separately. Therefore, the flowability of the powder is easily controlled, and the amount of absorber present in the laser beam diameter is easily controlled. This is described in detail below.

[0064] When the silicon monoxide (SiO) particles are all SiO particles that do not contain any region other than silicon monoxide, from the viewpoint of achieving preferred flowability, it is preferable that the average particle size of the oxide particles other than the silicon oxide particles (hereinafter also referred to as "base particles") is 5 μm or more, and larger than the average particle size of the SiO particles. The average particle size of the base particles is more preferably 10 μm or more and 200 μm or less. Furthermore, the average particle size of the base particles is preferably at least twice the average particle size of the SiO particles, or more preferably at least three times. Additionally, the average particle size of the base particles is preferably at least 10 times the average particle size of the SiO particles, more preferably at least 8 times. When the average particle size of the SiO particles is less than 5 μm, the average particle size of the base particles can be at least five times the average particle size of the SiO particles. When the average particle size of the SiO particles is 5 μm or more, the average particle size of the base particles can be at least five times the average particle size of the SiO particles. Furthermore, from the viewpoint of achieving high forming accuracy and promoting powder sintering or melting, the average particle size of the base material is preferably 200 μm or less, more preferably 150 μm or less. From the viewpoint of promoting powder melting, the average particle size of the base material is more preferably 100 μm or less, and still more preferably 50 μm or less. The average particle size of the base material can be 20 μm or more, or 40 μm or less.

[0065] When the silicon monoxide (SiO) particles are individually free of any region other than silicon monoxide, it is preferable that the average particle size of the SiO particles is 10 μm or less, and smaller than the average particle size of the parent material particles. When the SiO particles meet these conditions, there is a high probability that multiple SiO particles are dispersed and exist near the parent material particles. Therefore, the heat generated by the SiO absorbing the laser is effectively transferred to the parent material particles to promote the melting of the powder in the laser-irradiated portion. Considering the dispersibility and high filling density of SiO in the forming powder, the average particle size of the SiO particles is preferably as small as possible. At the same time, when the average particle size of the SiO particles is 1 μm or more, the dispersion of particles into the atmosphere by laser irradiation is suppressed, thus maintaining a suitable amount of SiO as an absorber in the forming powder. Therefore, the average particle size of the SiO particles is preferably 0.05 μm or more and 10 μm or less, more preferably 0.1 μm or more and 10 μm or less, still more preferably 0.5 μm or more and 10 μm or less, and still even more preferably 1 μm or more and 10 μm or less. The average particle size of SiO particles is preferably less than 1 / 2, or more preferably less than 1 / 3, of the average particle size of the parent material particles. The average particle size of SiO particles is preferably more than 1 / 10, and more preferably more than 1 / 8, of the average particle size of the parent material particles. When the average particle size of SiO particles is 1 μm or more and less than 5 μm, the average particle size of SiO particles is more preferably less than 1 / 5 of the average particle size of the parent material particles. When the average particle size of SiO particles is 5 μm or more and less than 10 μm, the average particle size of SiO particles can be more than 1 / 5 of the average particle size of the parent material particles.

[0066] When each silicon monoxide (SiO) particle contains regions other than silicon monoxide, the particle is called a "composite SiO particle". From the viewpoint of achieving flowability suitable for additive manufacturing methods, the average particle size of the composite SiO particles is preferably 5 μm or more and 200 μm or less. Furthermore, the average particle size of the composite SiO particles is preferably larger than the average diameter of the regions formed by the free SiO particles contained within the composite SiO particle. For example, the average particle size of the composite SiO particles can be as high as twice or more the average diameter of the regions formed by the free SiO particles contained within the composite SiO particle. The average particle size of the composite SiO particles is preferably 5 μm or more, and more preferably 10 μm or more. Additionally, the average particle size of the composite SiO particles is still more preferably five times or more the average diameter of the regions formed by the free SiO particles contained within the composite SiO particle. From the viewpoint of achieving high forming accuracy and promoting powder sintering or melting, when each silicon monoxide (SiO) particle contains regions other than silicon monoxide, the average particle size of the silicon monoxide-containing particles is preferably 200 μm or less, more preferably 150 μm or less. From the viewpoint of promoting powder melting, the average particle size of the composite SiO particles is more preferably 100 μm or less, and even more preferably 50 μm or less.

[0067] In SiO-containing particles, each containing SiO and compounds other than SiO, the average particle size of each constituent particle formed by free SiO is obtained by observing the powder, for example, using a scanning electron microscope (SEM), to determine the area of ​​each region where free SiO forms, and calculating the circular equivalent diameter of that area. Measurements are performed on multiple (more than 100) regions where free SiO forms, and the median is used as the average particle size of each constituent particle formed by free SiO.

[0068] In this embodiment, particle size refers to the circular equivalent diameter (Heywood diameter) of each individual particle. The average particle size of the particles formed from the specific composition contained in the forming powder does not refer to the particle size of an individual particle, but rather to the median (by number) of a group of particles with the same composition, and does not imply that the powder does not contain particles with sizes other than those described as the average particle size.

[0069] The average particle size can be calculated in the same way as the average particle size of the constituent particles, by observing the powder, for example, using a scanning electron microscope (SEM). The area of ​​each of the particles with a specific composition for which the average particle size is to be calculated is determined, and the circular equivalent diameter of that area is calculated. The method for calculating the average particle size can be applied regardless of the particle's state.

[0070] The molding powder of this embodiment preferably does not contain resin binders. This is because resin binders have a significantly lower melting point compared to other compounds contained in the powder, and therefore may be burned off by a large impact from laser irradiation, resulting in voids or defects in the molding area.

[0071] Furthermore, when the powder contains elemental carbon that is sublimable, the carbon combines with oxygen to escape as a gas, thus the volume occupied by the elemental carbon can become porous. In addition, elemental carbon can be rapidly vaporized by sublimation under laser irradiation, which adversely affects the molding process. Specifically, rapid vaporization may apply stress to the molten or solidified portions of the molding powder, leading to deformed molded articles. Therefore, it is preferable that the powder is substantially free of elemental carbon. However, the molar ratio of carbon atoms to metal elements in the various compounds contained in the powder only needs to be less than 1,000 ppm.

[0072] The forming powder in this embodiment is not limited to, for example, whether the ceramic forming powder is in a crystalline state, an amorphous state, or a mixture thereof. Furthermore, the powder and the manufactured ceramic molded article do not need to be completely identical in composition, and can differ from each other, particularly in terms of, for example, oxidized or nitrided states. <Manufacturing Methods of Ceramic Molded Articles>

[0073] According to one embodiment of this disclosure, a method for manufacturing a ceramic molded article (ceramic structure) is provided. The method for manufacturing a ceramic molded article according to this embodiment is characterized by using light to heat a material containing the ceramic molding powder of this disclosure to form the article, and by melting at least one or more oxide particles through heating.

[0074] The manufacturing method of this embodiment is applicable to additive manufacturing methods involving forming ceramic molded objects by laser irradiation of forming powder based on slice data generated from three-dimensional data of the ceramic molded object to be manufactured. Specifically, the manufacturing method of this embodiment is applicable to manufacturing methods using powder bed fusion or cladding methods. The manufacturing process includes manufacturing ceramic molded objects by alternately performing the following placement and irradiation steps multiple times.

[0075] In the placement step, oxide particles are placed on a base, and in the irradiation step, some or all of the oxide particles are irradiated with a laser, causing the oxide particles at the laser-irradiated locations to melt and solidify. This yields an intermediate-formed product.

[0076] When forming is performed using powder bed fusion, the placement and irradiation steps are as follows: the forming powder is spread and leveled on a substrate to achieve a predetermined thickness; then the powder is irradiated with a laser. When forming is performed using a cladding method, the placement and irradiation steps are as follows: the forming powder of this disclosure is sprayed to a predetermined position; and the predetermined position is irradiated with a laser.

[0077] There are no restrictions on the wavelength of the laser used in the forming process, but it is preferable to use a laser that is tuned to the desired focal size (such as a diameter of 10 μm to 2 mm) in a lens or optical fiber. The focal size is one of the parameters affecting the forming accuracy, and in some cases, to achieve a forming accuracy of 100 μm (0.1 mm), the laser linewidth is preferably comparable to the forming accuracy, and the focal size is preferably equal to or smaller than the laser diameter, i.e., 100 μm. Laser irradiation is not limited to being continuous or pulsed. For the laser, lasers with wavelengths around 1,000 nm, such as those generated by Nd:YAG lasers or Yb fiber lasers, can be suitably used. This is because the SiO composition exhibits a particularly high absorption capacity for light with a wavelength of about 1 μm.

[0078] Figures 1A to 1H This is a conceptual diagram of a three-dimensional forming apparatus using powder bed fusion (infrared laser melting method). (Refer to...) Figures 1A to 1H The schematic diagram illustrates the basic forming process of a manufacturing method using an infrared laser melting method, wherein the forming powder disclosed herein can be used.

[0079] like Figure 1A As shown, firstly, the raw material powder 101 is placed on the base 130 provided on the stand 151, and spread and leveled with rollers 152 to achieve a predetermined thickness. Therefore, as... Figure 1B As shown, a powder layer 102 is formed. (As indicated...) Figure 1C As shown, while scanning with the scanner unit 180, slice data generated based on the geometric data of the desired 3D model is irradiated with a laser emitted from the laser source 181 onto the powder layer 102. Within the laser irradiation range, the raw material powder melts and then solidifies, thereby forming a solidified portion 100 corresponding to one layer of slice data. Subsequently, as... Figure 1D As shown, the test bench 151 is lowered, and a new powder layer 102 is formed on the curing section 100. Figure 1E As shown, powder layer 102 is irradiated with a laser based on slice data. Figure 1F As shown, these steps are repeated a series of times corresponding to the slice data to provide a shaped article 110. The uncured raw material powder is indicated by reference numeral 103. Finally, as... Figure 1G As shown, remove the uncured raw material powder 103, and as... Figure 1HAs shown, unnecessary portions of the molded part 110 may be removed or the molded part 110 and the base 130 may be separated from each other as needed. Furthermore, heat treatment may be performed thereafter as required.

[0080] Reference Figure 2 Describe the cladding system. The cladding system involves ejecting powder from each of a plurality of powder supply holes 202 of a cladding nozzle 201 and irradiating the area where each powder is focused with a laser 203, thereby sequentially manufacturing ceramic molded articles at desired locations. The cladding system has the characteristic of being able to form on curved surfaces, etc.

[0081] Furthermore, the atmosphere can be controlled during the manufacturing process. In addition to using an air atmosphere, it is preferable to use an inert atmosphere containing nitrogen or rare gases, an atmosphere in which the compounds contained in the forming powder are easily reduced (such as an atmosphere containing hydrogen or a reduced pressure atmosphere), or an oxygen atmosphere. When such atmosphere control is implemented, powders containing compounds in a stoichiometric state (oxidized or reduced) can be used in the manufacture of ceramic molded articles.

[0082] In such a manufacturing process of the present embodiment as described above, the molding powder of the present disclosure enables stable molding and provides ceramic molded articles in which molding accuracy is ensured.

[0083] The ceramic molded articles manufactured using the forming powder of this embodiment are not limited to ceramic molded articles made of inorganic materials in a crystalline state. A portion or more than half of the ceramic molded article can be in an amorphous state, provided that desired physical property values ​​are obtained. Furthermore, the above-described manufacturing process enables the production of ceramic molded articles containing regions that are close to a metallic state, for example, generated by the reduction of the forming powder.

[0084] In addition to the forming step of obtaining an intermediate molded article from a powdered material, the method for manufacturing ceramic molded articles of this embodiment may include a heating step of subjecting the intermediate molded article to heat treatment, and the heating step is capable of repairing cracks present in the intermediate molded article.

[0085] Powder that has been melted by irradiation with an energy beam such as a laser is cooled and solidified by releasing heat to the surroundings. This forms an intermediate product.

[0086] In the case of ceramics, the thermal diffusivity of ceramics is lower than that of metals, thus the temperature difference between the molten site and its surroundings is relatively increased. Therefore, when forming is performed by infrared laser melting without preheating at high temperatures, numerous microcracks appear in the intermediate formed product. These microcracks are distributed throughout the intermediate formed product (both on its surface and inside). When the cross-section of the intermediate formed product is observed, for example, using a scanning electron microscope, most microcracks have widths ranging from a few nanometers to a few micrometers. Furthermore, the microcracks exhibit various lengths ranging from a few micrometers to a few millimeters.

[0087] When microcracks form in an intermediate molded part, stress is concentrated near the cracks when stress is applied to the molded part, thus reducing the mechanical strength of the molded part compared to the material in a bulk state. Therefore, it is preferable to repair the microcracks in some way.

[0088] An example of the forming powder disclosed herein is a ceramic forming powder mainly composed of Al2O3 particles, Y2O3 particles, and SiO particles. In such powders, microcracks self-repair during the firing step after an intermediate formed article is formed by the method described above. Within the intermediate formed article formed by the additive manufacturing method, regions containing Y as the main component, regions containing Si as the main component, and regions containing both Y and Si are locally formed. This additive manufacturing method involves forming the forming powder by laser irradiation. In a heat treatment step following the formation of the intermediate formed article, these regions are softened or melted by heat treatment to penetrate and fill the interior of the microcracks, thereby repairing the cracks. At this time, the heat treatment temperature only needs to be above 1,600°C, and preferably falls within the range of above 1,650°C and below 1,850°C.

[0089] In the manufacture of ceramic molded articles, the elemental ratio Y / Si (molar ratio) in the oxide structure is important for imparting crack repairability and for sufficiently increasing the mechanical strength and chemical resistance of the intermediate molded article. During the heating step, regions containing Y, regions containing Si, or regions containing both Y and Si (these regions exist in the intermediate molded article) are formed by compounds such as Y₂Si₂O₇ or Y₂SiO₅, and softened or melted to penetrate and fill the cracks. Thus, the cracks are repaired by compounds containing Y and Si. The repaired regions are compounds containing Y and Si, and compared to regions where silicon oxide is the main component, the reduction in mechanical properties and chemical resistance of the ceramic structure caused by these regions can be prevented. The above effect is achieved when the elemental ratio of Y to Si is 25 / 75 ≤ Y / Si ≤ 95 / 5. A lower limit for the amount of Y in the Y / Si elemental ratio is advantageous for the aforementioned crack-repairing regions to be compounds containing Y and Si. When the amount of Y is insufficient relative to Si, regions containing silicon oxide as the main component may remain in the structure, leading to a decrease in mechanical properties and chemical resistance. Furthermore, an upper limit to the amount of Y is advantageous for adequately repairing cracks in the molded article. When the amount of Si is insufficient, unrepairable cracked regions in the molded article are retained, and these regions may lead to a decrease in mechanical properties.

[0090] Furthermore, prior to the heating step, the presence of fine cracks can be utilized to impregnate the cracked portions with a modifier suitable for functional modification. For example, the intermediate molded part can be impregnated with a liquid containing a metallic element such as Li, Na, K, Mg, Ca, Y, Al, Ti, Zr, Hf, or Si, and then dried or fixed below 600°C. This configuration can further improve the three-point flexural strength of the ceramic molded part. <Ceramic Structures>

[0091] According to one embodiment of this disclosure, a ceramic structure is provided. Furthermore, the ceramic structure of this embodiment comprises the molding powder of this disclosure or a molded article manufactured by the method for manufacturing ceramic molded articles of this disclosure.

[0092] The ceramic structure of this embodiment contains at least Al, Y and Si, and the elemental ratio of Y to Si, Y / Si, satisfies 25 / 75≤Y / Si≤95 / 5.

[0093] The ceramic structure of this embodiment has the function of repairing cracks or fractures. For example, the ceramic structure has the function that when it is fractured by external force during use, it can self-repair the fracture by joining the fractured parts together and reheating, and the ceramic structure can recover to the same level of mechanical strength as the original. In this case, the heat treatment temperature only needs to be above 1,600°C, and preferably falls within the range of above 1,600°C and below 1,850°C, more preferably within the range of above 1,650°C and below 1,790°C. This feature is achieved due to the fact that the ceramic structure of this embodiment includes regions containing Y, regions containing Si, or regions containing both Y and Si, and the elemental ratio (molar ratio) of Y to Si is 25 / 75 ≤ Y / Si ≤ 95 / 5. When those regions are present, for example, compounds such as Y₂Si₂O₇ or Y₂SiO₅ are formed by heating and softened or melted to penetrate and fill cracks or fractures. Therefore, the cracks are repaired by compounds containing Y and Si. The repaired area is a compound containing Y and Si, and compared to the case where the area exists as a region containing silicon oxide as the main component, it is possible to prevent the reduction in mechanical properties and chemical resistance of the ceramic structure caused by the aforementioned area. A lower limit for the amount of Y in the Y / Si elemental ratio is advantageous for the aforementioned crack repair area to be a compound containing Y and Si. When the amount of Y is insufficient relative to Si, regions containing silicon oxide as the main component may remain in the structure, thereby causing a reduction in mechanical properties and chemical resistance. Furthermore, an upper limit for the amount of Y is advantageous for adequately repairing cracks or fractures in the molded article. When the amount of Si is insufficient, regions in the molded article where cracks or fractures cannot be repaired are retained, and these regions may lead to a reduction in mechanical properties.

[0094] In the ceramic structure of this embodiment, Y / Si preferably satisfies 1.0≤Y / Si≤10.0.

[0095] In addition, regarding the mole fraction, the ceramic structure of this embodiment preferably satisfies at least one of the following conditions: the content of Al is higher than the content of Y; or the content of Al is higher than the content of Si.

[0096] Furthermore, the ceramic structure of this embodiment preferably contains Zr. This configuration can further improve the mechanical strength of the ceramic structure. The composition of the ceramic structure, based on oxides, more preferably contains 3 mol% or more of Zr, and more preferably contains 7 mol% or more of Zr.

[0097] When the ceramic structure of this embodiment contains Zr, the ceramic structure preferably satisfies at least one of the following conditions: the content of Al is higher than the content of Zr; the content of Y is higher than the content of Zr; or the content of Zr is higher than the content of Si.

[0098] Furthermore, the ceramic structure of this embodiment preferably contains 50 mol% or more of Al in its composition, calculated as oxides. This configuration further improves the mechanical strength and chemical resistance of the ceramic structure. More preferably, the ceramic structure contains 60 mol% or more of Al; even more preferably, it contains 70 mol% or more of Al; and still even more preferably, it contains 80 mol% or more of Al.

[0099] However, in the ceramic structure of this embodiment, the molar fraction of Zr can be higher than that of Al.

[0100] The ceramic structure of this embodiment preferably contains Y as a multiple oxide. This configuration further improves the mechanical strength, chemical resistance, and plasma resistance of the ceramic structure. The ceramic structure preferably includes oxides containing both Y and Al. Oxides containing both Y and Al refer to multiple oxides primarily containing Y and Al. There is no limitation on the ratio of Y to Al in the oxides containing Y and Al, and preferred examples include Y3Al5O. 12 YAlO3 and Y4Al2O9. The ceramic structure preferably contains Y3Al5O3. 12 This is because it improves mechanical strength and chemical resistance. Furthermore, the ceramic structure preferably contains YAlO3 and Y4Al2O9, as this improves mechanical strength and plasma resistance. The oxide containing Y and Al preferably contains at least one of YAlO3 or Y4Al2O9.

[0101] Typically, only a stable phase is formed in oxides containing Y and Al, depending on the ratio of Y to Al. However, when forming, for example, by irradiation with an energy beam such as a laser, oxides containing Y and Al, including multiple phases containing metastable phases, can be formed in the ceramic structure due to the formation of a non-uniform structure in the ceramic structure by localized heating or changes in phase structure caused by rapid cooling and solidification.

[0102] Furthermore, the ceramic structure of this embodiment preferably contains Si as a composite oxide. This configuration further improves the mechanical strength and chemical resistance of the ceramic structure. More preferably, the ceramic structure includes oxides containing Y and Si. Oxides containing Y and Si refer to composite oxides primarily containing Y and Si.

[0103] The ceramic structure of this embodiment may include oxides containing Y and Al, as well as oxides containing Y and Si. Preferably, the volume of the oxides containing Y and Al in the ceramic structure is larger than the volume of the oxides containing Y and Si. This configuration further improves the mechanical strength and chemical resistance of the ceramic structure.

[0104] The preferred density of the ceramic structure in this embodiment is 4.19 g / cm³. 3 ]the following.

[0105] In addition, the three-point bending strength of the ceramic structure in this embodiment is preferably 152 [MPa] or higher.

[0106] In addition, the three-point bending strength [MPa] / density [g / cm³] of the ceramic structure in this embodiment is... 3 The preferred ratio is 40 [MPa·cm]. 3 / g] and above. <Application Example>

[0107] According to one embodiment of this disclosure, an apparatus is provided as an example of the application of the ceramic powder of this disclosure. The apparatus, as an example of the application, includes ceramic molded articles and at least any one of electrical components, optical components, metal components, or resin components.

[0108] Various types of devices can be formed by combining mechanical components, which are ceramic molded parts, with at least one of electrical, optical, metal, or resin components. Mechanical components are, for example, linkages used as a hand or arm, but can also be transmission components such as gears, cams, or shafts, or connecting components such as screws. The mechanical components of this embodiment can be used as heat-resistant or fire-resistant components. Devices containing mechanical components can be printing devices or office equipment, such as inkjet printers, laser printers, scanners, copiers, or multifunction peripherals. Devices can be imaging devices, such as cameras, displays, or projectors. Devices can be optical devices, such as interchangeable-lens or binoculars. Devices can be medical devices, such as X-ray imaging devices, CT systems, MRI systems, or endoscopes. Devices can be industrial devices, such as exposure devices, film-forming devices, generators, or robots. Devices can be any of a variety of mobile or transport devices, such as automobiles, aircraft, and ships. Additionally, devices can be scientific devices, such as nuclear reactors (fusion or fission reactors) or accelerators, or aerospace devices, such as artificial satellites. (Example)

[0109] The embodiments and comparative examples of this disclosure are illustrated in the following figures. Figures 3A to 3E The composition of the forming powder is shown in mole fraction. Figure 3A The composition of the forming powder is shown as a mass fraction in the figure. Figure 3BThe particle size and angle of repose of the powder used for forming (determined according to JIS R9301-2-2) are shown in the figure. Figure 3C The elemental ratios and molar ratios of oxides in the powder for forming are shown in the figure. Figure 3D-1 and Figure 3D-2 The firing temperature, firing time, density, relative density, three-point flexural strength (determined according to JIS R1601), crack self-healing property, alkali dissolution mass reduction (determined by the method described below for alkali resistance), and strength / density ratio are shown in the table below. Figure 3E middle. (Example 1)

[0110] The median particle size was approximately 20 μm and the density was 3.9 g / cm³. 3 The Al2O3 particles have a median particle size of approximately 30 μm and a density of 5.0 g / cm³. 3 The Y₂O₃ particles have a median particle size of approximately 4 μm and a density of 2.1 g / cm³. 3 SiO particles were added. Y₂O₃ particles and SiO particles were weighed at ratios of 2.2 g and 0.18 g relative to 10 g of Al₂O₃ particles, respectively, and loaded into a 1 L polyethylene container until 70% full. Then, 5 mm diameter zirconia beads were added. The mixture was subjected to a roller mixer for 30 minutes to prepare a product with… Figure 3A The powder has the indicated composition ratio. The powder has a rest angle of 34.7° and its flowability has been confirmed to be satisfactory. The powder composition is as follows: the powder contains Al, Y, and Si as oxide particles; and the molar ratio of Y to Si is 83 / 17, which meets the suitable composition range of this disclosure.

[0111] By using the ProX DMP 100 manufactured by 3D Systems, Inc., an intermediate form with a shape of 5 mm (width) × 5 mm (thickness) × 38 mm (total length) was manufactured as a precursor for forming ceramic shaped objects under the conditions of a stack thickness of 20 μm, a laser power of 45 W, a scanning speed of 100 mm / s and a scanning spacing of 140 μm in an infrared laser melting method.

[0112] The intermediate molded part was heat-treated by holding it at a maximum temperature of 1,700°C for 20 minutes. SEM images of the obtained structure and elemental mapping images of Al, Y, Si, and O evaluated according to SEM-EDX are shown below. Figure 4AIn the study, regions formed primarily of Al oxides, regions formed primarily of Y and Al oxides, and regions formed primarily of Y and Si oxides were observed. Based on SEM observation images and elemental mapping images, the areas of the regions formed primarily of Y and Al oxides and the regions formed primarily of Y and Si oxides were calculated, and a simple evaluation of the volume of each region in the structure was performed. Although the volume of the region formed primarily of Y and Si oxides was 5.9% of the total field of view, the volume of the region formed primarily of Y and Al oxides was 28.6% of the total field of view, and was greater than the volume of the region formed primarily of Y and Si oxides. This satisfies the preferred configuration of this disclosure. Furthermore, from the composition ratio of the semi-quantitative values ​​evaluated according to SEM-EDX, it was confirmed that the region formed primarily of Y and Al oxides has Y3Al5O 12 The regions of YAlO3 and Y4Al2O9.

[0113] The obtained structure had its cracked areas repaired, and its three-point bending strength was 173 MPa. Furthermore, the test piece that had broken into two pieces during the three-point bending strength test was placed so that the fractured surfaces of the two pieces were joined together. Then, the same steps as described above for heat treatment were performed again. As a result, the fractured parts were repaired, and the structure was confirmed to have joint at the fracture points.

[0114] In addition, the obtained structures were subjected to alkali resistance testing. An ETHOS PRO instrument manufactured by Milestone General KK was used for the test. The samples were immersed in a 20% (w / w) NaOH alkaline solution, heated to 200°C and held for 40 minutes, and the change in mass per unit area of ​​the samples before and after treatment was evaluated. As a reference, the alkali resistance of typical alumina materials in the equivalence test is approximately 2.6 g / m² in terms of change in mass per unit area. 2 The mass change per unit area in this embodiment is 3.2 g / m². 2 This is comparable to alumina materials, and satisfactory alkali resistance has been confirmed. The strength / density ratio is 46 MPa·cm. 3 / g, therefore the structure is light and strong enough. (Examples 2 to 4)

[0115] Prepared by simply changing the mixing ratio of the particles in Example 1. Figure 3A The amount of powder mixed as shown.

[0116] The same shapes were manufactured using the same forming apparatus and under the same forming conditions as those in Example 1, and the same heat treatment was performed. The structures obtained in Examples 1 to 4 each had repaired cracked areas, and each exhibited a three-point flexural strength of 150 MPa or higher. The strength / density ratio in each case was 40 MPa·cm³. 3 The weight is above / g, so each structure is light and strong enough. (Examination of Examples 1 to 4, 13 and 16)

[0117] The powder compositions of Examples 13 and 16 can be used instead of the powder compositions of Examples 1 to 4. For Examples 13 and 16, with... Figure 3A The powders shown in the mixed amounts differ from those in Example 1 only in the particle mixing ratio. Structures were obtained by similar molding processes using the same molding apparatus and under the same molding conditions as those in Example 1. The powder compositions of Examples 1 to 4, 13 and 16 each satisfy the following conditions.

[0118] The powder contains Al, Y and Si, and the molar ratio of Y to Si satisfies 25 / 75≤Y / Si≤95 / 5.

[0119] It satisfies the composition range where the elemental ratio of Al to Y (Al / Y) is 4.60 or higher and 73.78 or lower, and the elemental ratio of Al to Si (Al / Si) is 21.60 or higher and 87.45 or lower.

[0120] The powder contains more than 50 mol% aluminum oxide, more than 1.29 mol% and less than 15.02 mol% yttrium oxide, and more than 1.90 mol% and less than 7.18 mol% silicon oxide.

[0121] In addition, the ceramic molded articles obtained in Examples 1 to 4, 13 and 16 each satisfy the following conditions.

[0122] The ceramic molded part contains Al, Y and Si, and the elemental ratio of Y to Si, Y / Si, satisfies 25 / 75≤Y / Si≤95 / 5.

[0123] The elemental ratio of Al to Y, Al / Y, satisfies a value of 4.60 or higher and 73.78 or lower, and the elemental ratio of Al to Si, Al / Si, satisfies a value of 15.53 or higher and 140.35 or lower.

[0124] The ceramic molded product contains more than 50 mol% aluminum oxide, more than 1.29 mol% and less than 15.02 mol% yttrium oxide, and more than 1.90 mol% and less than 7.18 mol% silicon oxide.

[0125] Furthermore, the ceramic molded articles obtained in Examples 1 to 4 each satisfy the following condition: The density of the ceramic molded article is 4.19 g / cm³. 3 The following indicates that the three-point flexural strength of the ceramic molded article is above 152 MPa. "Three-point flexural strength [MPa] / density [g / cm³]" 3 The ratio is 40 MPa·cm. 3 / g or more. (Example 5)

[0126] To improve strength, the particle size was adjusted to a median of approximately 30 μm and a density of 5.7 g / cm³ using the same method as for other particles. 3 Yttrium-stabilized zirconium oxide 3YSZ particles (with 3 mol% Y2O3 ZrO2 particles added) to Figure 3A The amounts shown are mixed with the powder from Example 1. The rest angle of the powder is 35.9°, and the flowability is confirmed to be satisfactory. The powder satisfies the suitable composition range in the same manner as in Example 1. The same shape is manufactured using the powder, with the same molding apparatus as in Example 1, under the same molding conditions, and with the same heat treatment. SEM images of the obtained structures and elemental mapping images of Al, Y, Zr, Si, and O evaluated according to SEM-EDX are shown below. Figure 4B Regions formed primarily of Al oxides, regions formed primarily of Y and Al oxides, regions formed primarily of Zr and Y oxides, and regions formed primarily of Y and Si oxides were observed. Based on SEM observation images and elemental mapping images, the areas of the regions formed primarily of Y and Al oxides and the regions formed primarily of Y and Si oxides were calculated, and a simple evaluation of the volume of each region in the structure was performed. Although the volume of the region formed primarily of Y and Si oxides was 4.9% of the total field of view, the volume of the region formed primarily of Y and Al oxides was 12.7% of the total field of view, and was greater than the volume of the region formed primarily of Y and Si oxides. This satisfies the preferred configuration of this disclosure. Furthermore, from the composition ratio of the semi-quantitative values ​​evaluated according to SEM-EDX, it was confirmed that the region formed primarily of Y and Al oxides has Y3Al5O 12 The regions of YAlO3 and Y4Al2O9.

[0127] The resulting structure had its cracked areas repaired, and its three-point bending strength exceeded 200 MPa. Furthermore, the test piece that had broken into two pieces during the three-point bending strength test was placed so that the fractured surfaces of the two pieces were joined together. Then, the same steps as described above for heat treatment were performed again. As a result, the fractured parts were repaired, and the structure was confirmed to have joint at the fracture points.

[0128] In addition, the alkali resistance of the obtained structure was determined using the same method as in Example 1, and the change in mass per unit area of ​​the samples before and after treatment was evaluated. The change in mass per unit area in this example was 3.4 g / m². 2 This is comparable to alumina materials, and satisfactory alkali resistance has been confirmed. The strength / density ratio is 55 MPa·cm. 3 / g, therefore the structure is light and strong enough. (Examples 6 to 12)

[0129] The preparation was achieved by simply changing the mixing ratio of the particles in Example 5. Figure 3A The powder was mixed in the amounts shown. The same shapes were manufactured using the same molding apparatus and under the same molding conditions as those in Example 1, and the same heat treatment was performed. The structures obtained in Examples 6 to 12 each had repaired cracked areas, and each had a three-point flexural strength value of over 150 MPa. The strength / density ratio in each case was 40 MPa·cm. 3 The weight is above / g, so each structure is light and strong enough. (Examination of Examples 5 to 12, 14, 15, 17, 18 and 21)

[0130] The powder compositions of Examples 14, 15, 17, 18, and 21 can be used instead of the powder compositions of Examples 6 to 12. For Examples 14, 15, and 17 to 21, the powder compositions are... Figure 3A The quantities shown are mixed and have Figure 3C The powder with the particle size shown differs from the powder of Example 5 only in the mixing ratio of the particles. The structure was obtained by similar molding processes using the same molding apparatus and under the same molding conditions as those in Example 5. Figure 3D-2 The value “0.33” shown as Y / Si (elemental ratio) falls within the range of Y / Si ≥ 25 / 75 due to conventional rounding conventions. Figure 3D-2 The value “19.12” shown as Y / Si (elemental ratio) falls within the range of Y / Si ≤ 95 / 5 due to conventional rounding conventions. The powder compositions of Examples 5 to 12, 14, 15, 17, 18 and 21 each satisfy the following conditions.

[0131] The powder contains Al, Y and Si, and the molar ratio of Y to Si satisfies 25 / 75≤Y / Si≤95 / 5.

[0132] It satisfies the composition range where the elemental ratio of Al to Y (Al / Y) is 4.60 or higher and 73.78 or lower, and the elemental ratio of Al to Si (Al / Si) is 21.60 or higher and 87.45 or lower.

[0133] The composition ranges that satisfy the following conditions: the element ratio of Al to Zr is greater than or equal to 9.89 and less than 44.58; the element ratio of Y to Zr is greater than or equal to 0.18 and less than 7.64; and the element ratio of Zr to Si is greater than or equal to 0.55 and less than 7.35.

[0134] The powder contains more than 50 mol% aluminum oxide, more than 1.29 mol% and less than 15.02 mol% yttrium oxide, and more than 1.90 mol% and less than 7.18 mol% silicon oxide.

[0135] The powder contains more than 3.93 mol% and less than 13.97 mol% zirconium oxide. (Examples 22 to 26)

[0136] Prepared by simply changing the particle size of the particles in Example 5 Figure 3A The powders were mixed in the amounts shown. The rest angle of each powder was less than 40°, and the flowability was confirmed to be satisfactory. The same shapes were manufactured using the same molding apparatus and under the same molding conditions as those in Example 1, and the same heat treatment was performed. The structures obtained in Examples 22 to 26 were each in a state where the cracked areas were repaired, and each had a three-point flexural strength value of over 150 MPa. The strength / density ratio in each case was 40 MPa·cm. 3 The weight is above / g, so each structure is light and strong enough.

[0137] In addition, the ceramic molded articles obtained in Examples 5 to 12, 14, 15 and 17 to 26 each satisfy the following conditions.

[0138] The ceramic molded part contains Al, Y and Si, and the elemental ratio of Y to Si, Y / Si, satisfies 25 / 75≤Y / Si≤95 / 5.

[0139] The elemental ratio of Al to Y, Al / Y, satisfies a value of 4.60 or higher and 73.78 or lower, and the elemental ratio of Al to Si, Al / Si, satisfies a value of 15.53 or higher and 140.35 or lower.

[0140] The elemental ratio of Al to Zr (Al / Zr) satisfies a value of 9.89 or higher and 44.58 or lower, the elemental ratio of Y to Zr (Y / Zr) satisfies a value of 0.18 or higher and 7.64 or lower, and the elemental ratio of Zr to Si (Zr / Si) satisfies a value of 0.55 or higher and 7.35 or lower.

[0141] The ceramic molded article contains more than 50 mol% aluminum oxide, more than 1.29 mol% and less than 15.02 mol% yttrium oxide, more than 1.90 mol% and less than 7.18 mol% silicon oxide, and more than 3.93 mol% and less than 13.97 mol% zirconium oxide.

[0142] Furthermore, the ceramic molded articles obtained in Examples 5 to 12 and 22 to 26 each satisfy the following condition: The density of the ceramic molded article is 4.19 g / cm³. 3 The three-point flexural strength of the ceramic molded article is 152 MPa or higher. "Three-point flexural strength [MPa] / density [g / cm³]" 3 The ratio is 40 [MPa·cm]. 3 / g] and above. (Comparative Example 1)

[0143] The median particle size was approximately 20 μm and the density was 3.9 g / cm³. 3 The Al2O3 particles have a median particle size of approximately 30 μm and a density of 5.7 g / cm³. 3 The yttrium-stabilized zirconium oxide 3YSZ particles have a median particle size of approximately 4 μm and a density of 2.1 g / cm³. 3 SiO particles, and in Figure 3A The amounts shown are mixed. This powder composition is an example where the molar ratio of Y to Si is 0.15 / 0.85, which does not meet the suitable composition range of this disclosure. The same shape was manufactured using the same forming apparatus as those in Example 1 and under the same forming conditions. Heat treatment was performed by changing the maximum temperature to 1,790°C. In the obtained structure, the cracked areas were not adequately repaired, and the three-point flexural strength of the obtained structure was as low as 61 MPa, with a strength / density ratio of 15 MPa·cm. 3 / g, therefore it cannot be said that the structure is both light and strong. (Comparative Example 2)

[0144] The median particle size was approximately 20 μm and the density was 3.9 g / cm³. 3 The Al2O3 particles have a median particle size of approximately 30 μm and a density of 5.0 g / cm³. 3 Y₂O₃ particles and SiO particles with a median particle size of approximately 30 μm, and with Figure 3AThe amounts shown are mixed. This powder composition is an example where the molar ratio of Y to Si is 1.00 / 0.00, which does not meet the suitable composition range of this disclosure. The same shape was manufactured using the same forming apparatus as those in Example 1 and under the same forming conditions, and the same heat treatment was performed. In the obtained structure, the cracked areas were not adequately repaired, and the three-point flexural strength of the obtained structure was as low as 64 MPa, with a strength / density ratio of 17 MPa·cm. 3 / g, therefore it cannot be said that the structure is both light and strong. (Comparative Example 3)

[0145] The median particle size was approximately 20 μm and the density was 3.9 g / cm³. 3 The Al2O3 particles have a median particle size of approximately 28 μm and a density of 2.2 g / cm³. 3 The SiO2 particles have a median particle size of approximately 4 μm and a density of 2.1 g / cm³. 3 SiO particles, and in Figure 3A The amounts shown are mixed. This powder composition is an example where the molar ratio of Y to Si is 0.00 / 1.00, which does not meet the suitable composition range of this disclosure. The same shape was manufactured using the same forming apparatus as those in Example 1 and under the same forming conditions, and heat-treated by changing the maximum temperature to 1,690°C. The resulting structure was in a state where the cracked areas were repaired, and the three-point flexural strength was 103 MPa. Furthermore, the alkali resistance of the obtained structure was determined by the same method as in Example 1, and the change in mass per unit area of ​​the sample before and after treatment was evaluated. The change in mass per unit area in this example was 430 g / m². 2 This is more than 100 times the value of alumina materials, and poor alkali resistance has been confirmed.

[0146] According to this embodiment, by using a direct manufacturing system (powder bed fusion or infrared laser melting method), it is possible to provide a ceramic molded article that has a mechanical strength of 150 MPa or more, and further 200 MPa or more, and has a mass reduction of 10 g / m² per unit area. 2 The following, further 5g / m 2 It has the following alkali resistance and further has the ability to repair fine cracks.

[0147] According to this disclosure, an advantageous technique can be provided for manufacturing ceramic structures with high mechanical strength, chemical resistance, and crack repairability using additive manufacturing methods.

[0148] Although this disclosure has been described with reference to embodiments, it should be understood that this disclosure is not limited to the disclosed embodiments. The scope of the appended claims should be given the broadest interpretation to cover all such modifications and equivalent structures and functions.

Claims

1. A ceramic forming powder comprising one or more oxide particles, The powder contains at least Al, Y, and Si, and The powder has an elemental ratio of Y to Si that satisfies 25 / 75≤Y / Si≤95 / 5.

2. The powder according to claim 1, wherein the Y / Si ratio satisfies Y / Si ≥ 1.

0.

3. The powder according to claim 1, wherein the Y / Si satisfies Y / Si≤10.

0.

4. The powder according to claim 1, wherein the powder satisfies at least one of the following conditions: The content of Al is higher than that of Y; or The content of Al is higher than that of Si.

5. The powder according to claim 1, wherein the powder satisfies at least one of the following conditions: The elemental ratio of Al to Y, Al / Y, is greater than 4.60 and less than 73.78; or The elemental ratio of Al to Si is above 21.60 and below 87.

45.

6. The powder according to claim 1, wherein the powder further comprises Zr.

7. The powder according to claim 6, wherein the powder satisfies at least one of the following conditions: The content of Al is higher than that of Zr; The content of Y is higher than that of Zr; or The Zr content is higher than the Si content.

8. The powder according to claim 6, wherein the powder satisfies at least one of the following conditions: The elemental ratio of Al to Zr is above 9.89 and below 44.58; The elemental ratio of Y to Zr is greater than 0.18 and less than 7.64; or The elemental ratio of Zr to Si is greater than 0.55 and less than 7.

35.

9. The powder according to claim 1, wherein the powder comprises silicon monoxide.

10. The powder according to claim 1, wherein the one or more oxide particles comprise aluminum oxide particles and silicon oxide particles.

11. The powder of claim 10, wherein each of the silicon oxide particles comprises silicon monoxide.

12. The powder according to claim 10, wherein the one or more oxide particles comprise yttrium oxide particles.

13. The powder according to claim 10, wherein the one or more oxide particles comprise zirconium oxide particles.

14. The powder of claim 13, wherein each of the zirconium oxide particles comprises Y.

15. The powder according to any one of claims 1 to 13, wherein the powder satisfies at least one of the following conditions: The powder contains more than 50 mol% aluminum oxide; The powder contains 1.29 mol% or more and 15.02 mol% or less of yttrium oxide; or The powder contains more than 1.90 mol% and less than 7.18 mol% of silicon oxide.

16. The powder according to any one of claims 1 to 14, wherein the powder comprises 3.93 mol% or more and 13.97 mol% or less of zirconium oxide.

17. The powder according to claim 10, wherein the average particle size of the oxide particles other than the silicon oxide particles contained in the powder is 10 μm or more and 200 μm or less.

18. The powder according to claim 10, wherein the average particle size of the oxide particles other than the silicon oxide particles contained in the powder is 10 μm or more and 50 μm or less.

19. The powder according to claim 1, wherein the stationary angle of the powder is less than 40°.

20. A method for manufacturing a ceramic molded article, comprising shaping the article by light heating using a material containing powder according to any one of claims 1 to 18, wherein at least one oxide particle is melted by said heating.

21. A method for manufacturing a ceramic molded article, comprising: The forming step of obtaining an intermediate molded article from a material using powder according to any one of claims 1 to 18, and The intermediate formed article is subjected to a heating step involving heat treatment. The heating step includes repairing cracks present in the intermediate molded material.

22. The method for manufacturing a ceramic molded article according to claim 21, wherein the heating step comprises performing the heat treatment at a temperature above 1,600°C and below 1,850°C.

23. A ceramic structure comprising Al, Y and Si, wherein the ceramic structure has an elemental ratio Y / Si satisfying 25 / 75≤Y / Si≤95 / 5.

24. The ceramic structure according to claim 23, wherein the Y / Si ratio satisfies 1.0 ≤ Y / Si ≤ 10.

0.

25. The ceramic structure according to claim 23, wherein the ceramic structure satisfies at least one of the following conditions: The content of Al is higher than that of Y; or The content of Al is higher than that of Si.

26. The ceramic structure according to claim 23, wherein the ceramic structure satisfies at least one of the following conditions: The elemental ratio of Al to Y, Al / Y, is greater than 4.60 and less than 73.78; or The elemental ratio of Al to Si is above 15.53 and below 140.

35.

27. The ceramic structure according to claim 23, further comprising Zr.

28. The ceramic structure according to claim 27, wherein the ceramic structure satisfies at least one of the following conditions: The content of Al is higher than that of Zr; The content of Y is higher than that of Zr; or The Zr content is higher than the Si content.

29. The ceramic structure according to claim 27, wherein the ceramic structure satisfies at least one of the following conditions: The elemental ratio of Al to Zr is above 9.89 and below 44.58; The elemental ratio of Y to Zr is greater than 0.18 and less than 7.64; or The elemental ratio of Zr to Si is greater than 0.55 and less than 7.

35.

30. The ceramic structure according to claim 23, wherein the ceramic structure satisfies at least one of the following conditions: The ceramic structure contains more than 50 mol% aluminum oxide; The ceramic structure contains 1.29 mol% or more and 15.02 mol% or less of yttrium oxide; The ceramic structure comprises 1.90 mol% or more and 7.18 mol% or less of silicon oxide; or The ceramic structure contains more than 3.93 mol% and less than 13.97 mol% of zirconium oxide.

31. The ceramic structure according to claim 23, comprising oxides containing Y and Al.

32. The ceramic structure according to claim 31, wherein the oxide containing Y and Al comprises at least one of YAlO3 or Y4Al2O9.

33. The ceramic structure according to claim 23, comprising an oxide containing Y and Si.

34. The ceramic structure according to claim 23, comprising oxides containing Y and Al and oxides containing Y and Si, wherein the volume of the oxides containing Y and Al is greater than the volume of the oxides containing Y and Si.

35. The ceramic structure according to any one of claims 23 to 34, wherein the ceramic structure satisfies at least one of the following conditions: The density of the ceramic structure is 4.19 g / cm³. 3 the following; The three-point bending strength of the ceramic structure is above 152 MPa; or The ceramic structure has a three-point bending strength (MPa) and density (g / cm³). 3 The ratio is 40 MPa·cm 3 / g or more.

36. An apparatus comprising: The ceramic structure according to any one of claims 23 to 35; as well as At least one of electrical components, optical components, metal components, or resin components.

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