Ceramic molding powder, method for manufacturing ceramic molded objects, and ceramic structures and equipment

Abstract

To provide a technology that offers advantages in manufacturing ceramic structures with high mechanical strength and chemical resistance, as well as crack repairability, through additive manufacturing. [Solution] A powder for ceramic molding containing one or more types of oxide particles is provided, characterized in that it contains at least Al, Y, and Si, and the elemental ratio of Y to Si, Y / Si, satisfies 25 / 75 ≤ Y / Si ≤ 95 / 5.

Description

[Technical Field]

[0001] This invention relates to a ceramic molding powder suitably used in additive manufacturing, which forms molded objects by additive manufacturing technology, a method for manufacturing ceramic molded objects using the powder, and a ceramic structure. [Background technology]

[0002] In recent years, additive manufacturing technology, which involves adding material based on three-dimensional data of a model to be manufactured to obtain a desired structure, has become increasingly popular for applications such as quickly creating prototypes or manufacturing small quantities of items. In the manufacture of metal articles, direct fabrication is widely used, in which a laser beam is irradiated onto metal powder based on three-dimensional data of the model to solidify the powder and create the shape. This method makes it possible to obtain dense and diverse articles by effectively melting and solidifying the metal powder. Patent Document 1 describes how to achieve excellent molding accuracy by adding a rare earth oxide, which has a higher absorption capacity than Al2O3 for wavelengths of light contained in infrared laser light, as an absorber to Al2O3 powder, thereby suppressing light diffusion. Patent Document 2 describes how to reduce the cost of the raw material powder by using SiO as the absorber. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2019-19051 [Patent Document 2] Japanese Patent Publication No. 2023-72682 [Overview of the project] [Problems that the invention aims to solve]

[0004] In the shaped object disclosed in Patent Document 1, it is necessary to repair the fine cracks generated during shaping by impregnation. However, in the repair by impregnation, especially in a shaped object with a complex shape, the impregnating liquid does not spread evenly, resulting in areas that cannot be repaired and non-uniform composition, which may cause problems such as strength reduction and cracking.

[0005] The shaped object disclosed in Patent Document 2 contains a large amount of silica component, and there is room for improvement in mechanical properties and chemical resistance. Therefore, an object of the present invention is to provide an advantageous technique for manufacturing a ceramic structure having high mechanical strength, chemical resistance, and crack repairability using an additive manufacturing method.

Means for Solving the Problems

[0006] To solve the above problems, a first aspect is a powder for ceramic shaping containing one or more types of oxide particles, containing at least Al, Y, and Si, and the element ratio Y / Si of Y and Si satisfies 25 / 75 ≦ Y / Si ≦ 95 / 5.

[0007] A second aspect is a method for manufacturing a ceramic shaped object by shaping a shaped object by heating a material using a powder for ceramic shaping containing at least Al, Y, and Si and having an element ratio Y / Si of Y and Si satisfying 25 / 75 ≦ Y / Si ≦ 95 / 5 with light, characterized in that at least one type of oxide particle is melted by the heating.

[0008] Also, a third aspect is a ceramic structure containing Al, Y, and Si, and the element ratio Y / Si of Y and Si satisfies 25 / 75 ≦ Y / Si ≦ 95 / 5.

[0009] Also, as an application example, there is an apparatus including the above ceramic shaped object and at least any one of electrical components, optical components, metal components, and resin components. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an advantageous technology for manufacturing ceramic structures with high mechanical strength and chemical resistance, as well as crack repairability, using additive manufacturing. [Brief explanation of the drawing]

[0011] [Figure 1A] A schematic cross-sectional view illustrating a part of the process of one embodiment of a method for manufacturing a molded object using powder bed fusion bonding. [Figure 1B] A schematic cross-sectional view illustrating a part of the process of one embodiment of a method for manufacturing a molded object using powder bed fusion bonding. [Figure 1C] A schematic cross-sectional view illustrating a part of the process of one embodiment of a method for manufacturing a molded object using powder bed fusion bonding. [Figure 1D] A schematic cross-sectional view illustrating a part of the process of one embodiment of a method for manufacturing a molded object using powder bed fusion bonding. [Figure 1E] A schematic cross-sectional view illustrating a part of the process of one embodiment of a method for manufacturing a molded object using powder bed fusion bonding. [Figure 1F] A schematic cross-sectional view illustrating a part of the process of one embodiment of a method for manufacturing a molded object using powder bed fusion bonding. [Figure 1G] A schematic cross-sectional view illustrating a part of the process of one embodiment of a method for manufacturing a molded object using powder bed fusion bonding. [Figure 1H] A schematic cross-sectional view illustrating a part of the process of one embodiment of a method for manufacturing a molded object using powder bed fusion bonding. [Figure 2] A schematic cross-sectional view illustrating one embodiment of a method for manufacturing molded objects using the cladding method. [Figure 3A] A table showing the composition of the molding powders in the examples and comparative examples, expressed as mole fractions. [Figure 3B] A table showing the composition of the molding powders for the examples and comparative examples, expressed as mass fractions. [Figure 3C]A table showing the particle size and angle of repose of the molding powders for the examples and comparative examples. [Figure 3D] A table showing the elemental ratios of various elements and the molar ratios of oxides in the molding powders of the examples and comparative examples. [Figure 3E] A table showing the results for the examples and comparative examples. [Figure 4A] SEM observation images of one example of multiple embodiments of the structure of the present invention, and elemental mapping images of Al, Y, Si, and O obtained by SEM-EDX evaluation. [Figure 4B] SEM observation images of one example of multiple embodiments of the structure of the present invention, and elemental mapping images of Al, Y, Zr, Si, and O obtained by SEM-EDX evaluation. [Modes for carrying out the invention]

[0012] The embodiments for carrying out the present invention will be described below with reference to the drawings, but the present invention is not limited in any way to the following specific examples or drawings.

[0013] In this specification, aluminum oxide may be described as alumina or Al2O3, yttrium oxide as Y2O3, silicon monoxide as SiO, silicon dioxide as silica, silicon oxide or SiO2, and zirconium oxide as zirconia or ZrO2. Each substance may have multiple crystalline states or an amorphous state. Furthermore, this does not exclude the presence of other impurities, such as some oxygen or nitrogen.

[0014] In this embodiment, in a unit mass of powder (for example, 10 g), the percentage of the amount of substance (mol) of each compound relative to the total amount of substance (mol) of all compounds is defined as the mole fraction (mol%).

[0015] Furthermore, for example, when we say "SiO-containing particles" or "silicon monoxide-containing particles," we are referring to independent particles containing SiO, while when we say "SiO particles" or "silicon monoxide particles," we are referring to independent particles that are mainly composed of SiO. Here, "mainly" means 50 mol% or more, preferably 75 mol% or more, and more preferably 90 mol% or more. SiO particles and silicon monoxide particles contain 50 mol% or more of SiO, preferably 75 mol% or more, and more preferably 90 mol% or more. The same applies to Al2O3 and Y2O3.

[0016] <Ceramic molding powder> As one embodiment of this invention, a powder for ceramic molding is provided. Hereinafter, the powder for ceramic molding may be referred to as ceramic molding powder or molding powder.

[0017] The molding powder of this embodiment is suitably used in direct molding methods, particularly in methods called powder bed fusion bonding or infrared laser fusion bonding. The molding powder of this embodiment (hereinafter also referred to as "material powder," "raw material powder," or simply "powder") is composed of multiple particles that are independent of each other, and is suitably used in additive manufacturing, which involves irradiating with laser light to form a shape. It mainly consists of one or more types of oxide particles. These particles can be classified into multiple types, but they can also be composed of a large number of particles with uniform shape and material.

[0018] The molding powder of this embodiment contains one or more types of oxide particles, the oxide particles containing at least Al, Y, and Si. Furthermore, the elemental ratio of Y to Si, Y / Si, satisfies 25 / 75 ≤ Y / Si ≤ 95 / 5. In this way, the intermediate molded object can self-repair cracks by heating.

[0019] If the Y / Si ratio is lower than 25 / 75, the resulting ceramic structure (ceramic molded object) cannot achieve sufficiently high mechanical strength, particularly three-point bending strength. A Y / Si ratio of 25 / 75 or higher is preferable for the ceramic structure (ceramic molded object) obtained according to this embodiment to satisfy a mechanical strength, particularly a three-point bending strength of 50 MPa or higher. A three-point bending strength value of 100 MPa or higher is more preferable, 150 MPa or higher is even more preferable, and 170 MPa or higher is very preferable. The three-point bending strength value can also be 200 MPa or higher. The three-point bending strength value may be 1000 MPa or lower, 500 MPa or lower, or 400 MPa or lower. Furthermore, if the Y / Si ratio is too low, the resulting ceramic structure cannot achieve sufficiently high chemical resistance, particularly alkali resistance. A Y / Si ratio of 25 / 75 or higher is preferable for the mass change per unit area of ​​the resulting ceramic structure to be 100 g / m². 2 The following is preferable: The mass change per unit area of ​​the resulting ceramic structure is 50 g / m². 2 More preferably, the following is true: 10 g / m 2 It is even more preferable that the following conditions apply: 5 g / m 2 The following is even more preferable. The alkali resistance of the resulting ceramic structure can be measured, for example, in accordance with JIS R1614. Furthermore, the resulting ceramic structure has a density of 4.00 g / cm³. 3 Preferably, the density is 4.00 g / cm³. 3 Therefore, it can be considered a sufficiently lightweight ceramic structure.

[0020] In the molding powder of this embodiment, the ratio of Y / Si can be Y / Si ≥ 0.43, Y / Si ≥ 0.50, more preferably Y / Si ≥ 1.0, and even more preferably Y / Si ≥ 2.0. When Y / Si = 2.0, the ratio of Y2O3 to SiO2 is approximately the same when converted to oxides.

[0021] Furthermore, if the Y / Si ratio is too high, the self-repairing properties of the cracks in the ceramic structure obtained by this embodiment cannot be sufficiently maintained. A Y / Si ratio of 95 / 5 or less is preferable for maintaining the self-repairing properties of the cracks in the ceramic structure, and is also preferable if Si is included as SiO, in order to sufficiently obtain the function of a laser light absorber.

[0022] Y / Si is preferably Y / Si ≤ 10.0, more preferably Y / Si ≤ 9.0, and even more preferably Y / Si ≤ 4.9. It may also be Y / Si ≤ 4.0 or Y / Si ≤ 3.0. Furthermore, in the molding powder of this embodiment, it is preferable that at least one of the following conditions is met: Al is greater than Y in mole fraction, and Al is greater than Si.

[0023] The Si contained in the molding powder of this embodiment is preferably contained as an oxide of Si, and more preferably as SiO or SiO2. Furthermore, Si is preferably contained as oxide particles, and more preferably as silicon oxide particles. The silicon oxide particles include SiO particles (silicon monoxide particles), SiO2 particles (silicon dioxide particles, silicon oxide particles), SiO-containing particles (silicon monoxide-containing particles), SiO2-containing particles (silicon dioxide-containing particles, silicon oxide-containing particles), mixtures of any of these, and mixtures of SiO particles and SiO2 particles.

[0024] Furthermore, the Al contained in the molding powder according to this embodiment is preferably contained as an oxide of Al, preferably as Al2O3, and preferably contains particles containing an oxide of Al, Al2O3-containing particles (aluminum oxide-containing particles), and Al2O3 particles (aluminum oxide particles) as oxide particles. The particles other than silicon oxide particles are preferably 10 μm or more and 200 μm or less in size, and more preferably 10 μm or more and 50 μm or less.

[0025] In the composition of the molding powder of this embodiment, it is preferable that the powder contains 50 mol% or more of Al in terms of oxide. This further enhances the mechanical strength and chemical resistance of the ceramic structure. More preferably, the molding powder contains 60 mol% or more of Al, more preferably 70 mol% or more, and even more preferably 80 mol% or more.

[0026] Furthermore, the molding powder of this embodiment preferably contains Zr, and more preferably contains it as ZrO2. Moreover, it is preferable to include particles containing an oxide of Zr as oxide particles, and more preferably to include ZrO2-containing particles (zirconium oxide-containing particles) and ZrO2 particles (zirconium oxide particles).

[0027] This method can further increase the mechanical strength of the ceramic structure. More preferably, the composition of the molding powder contains 3 mol% or more of Zr in terms of oxide, and more preferably 7 mol% or more.

[0028] In the molding powder of this embodiment, it is preferable that at least one of the following conditions is met in terms of mole fraction: Al is greater than Zr, Y is greater than Zr, and Zr is greater than Si. However, the mole fraction of Zr may be higher than the mole fraction of Al.

[0029] Furthermore, if the molding powder of this embodiment contains Y, Y2O 3、 It is preferable that it contains as such. Furthermore, it is preferable that it contains particles containing an oxide of Y as oxide particles, and it is preferable that it contains Y2O3-containing particles (yttrium oxide-containing particles) and Y2O3 particles (yttrium oxide particles).

[0030] Al2O3, Y2O 3、The notations of compounds such as SiO and SiO2 do not limit the composition of the stated stoichiometric ratio, and an error in the constituent element ratio within ±30% from the stoichiometric ratio normalized by the metal element is allowed. For example, a compound with a constituent element ratio of Si:O = 100:130 is also included in the notation of SiO. That is, SiO can be expressed as SiO m (0.7 ≤ m ≤ 1.3).

[0031] The powder for shaping of this embodiment contains one or more types of oxide particles, and as the oxide particles, it is preferable to contain Al2O3 particles and silicon oxide particles. The silicon oxide particles include SiO particles, SiO2 particles, or those in which SiO particles and SiO2 particles are mixed. Further, the powder for shaping of this embodiment preferably contains Y2O3 particles. Also, the powder for shaping of this embodiment preferably contains ZrO2 particles. The ZrO2 particles may contain Y.

[0032] As described above, the powder for shaping of this embodiment may contain particles other than silicon oxide particles. The particles other than silicon oxide particles can be Al2O3 particles, Y2O3 particles, ZrO2 particles, etc. From the viewpoint of realizing preferable fluidity, the average particle size of the particles other than silicon oxide particles can 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 be, for example, 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. It is preferable that the average particle size of the oxide particles other than silicon oxide particles is 10 μm or more and 50 μm or less, and more preferably 20 μm or more and 40 μm or less.

[0033] The molding powder of this embodiment preferably contains particles that have high absorption capacity for light of a wavelength irradiated during molding (laser light), and is particularly preferably containing SiO-containing particles. SiO is brown or black in color and has a relatively higher light absorption capacity for laser light than Al2O3 or Y2O3 contained in the molding powder. When SiO absorbs laser light, Si changes from divalent to tetravalent, changing from a metastable state of SiO to a more stable state of SiO2, and its light absorption capacity for laser light decreases. By molding using a powder in which SiO having such properties is added as an absorber to Al2O3 or Y2O3, the following effects can be obtained.

[0034] The first effect is that the absorber, SiO, efficiently absorbs the laser light used during manufacturing, becoming hot, which transfers heat to other compounds within a region corresponding to the focal size of the laser beam, causing a temperature increase. As a result, the region corresponding to the focal size of the laser beam can be effectively heated locally, clarifying the interface between the region where the powder is to be solidified (the region irradiated with laser light) and the region where it is not to be solidified (the region not irradiated with laser light), thereby improving the accuracy of the fabrication.

[0035] The second effect is that SiO is transformed into SiO2, which has low light absorption capacity, by laser irradiation, and the light absorption in the part of the powder that has solidified after being irradiated with laser light (solidified part) is suppressed. xIf the light absorption capacity of the SiO is reduced to 5 / 6 times or less of what it was before laser irradiation, then even if the solidified area is irradiated with laser light under the same conditions as during solidification, the molding accuracy will not be significantly affected. In other words, there is almost no SiO, which acts as an absorber, in the solidified area. Therefore, even if laser light is irradiated, the temperature rise seen before solidification does not occur. Furthermore, even if the powder adjacent to the solidified area is irradiated with laser light, deformation and alteration of the solidified area are suppressed. As a result, the process margin, such as the laser irradiation conditions, is widened, and the impact of fluctuations in irradiation conditions on molding accuracy can be reduced. To obtain sufficient molding accuracy, it is preferable that the light absorption capacity of SiO alone before laser irradiation is 1.2 times or more, and preferably 2 times or more, compared to the light absorption capacity of the absorber with changed composition after laser irradiation.

[0036] Thus, by selectively irradiating the powder of the present invention with laser light to perform fabrication, the first and second effects described above can be obtained, enabling highly accurate fabrication. Furthermore, since SiO is commercially available as a negative electrode for lithium-ion secondary batteries, it can be procured at a lower cost compared to other compounds that can be used as absorbers.

[0037] However, it is possible to replace at least a portion of SiO with SiO2, and SiO may be replaced with SiO2 when heating other than laser light is used. Also, TiO or other materials can be used instead of SiO as an absorber, in which case the powder may contain SiO2, and the Si used to evaluate Y / Si may originate from SiO2. Alternatively, the powder may contain silicon compounds other than elemental silicon or silicon oxide (e.g., silicon nitride, silicon carbide, metal silide), and the Si used to evaluate Y / Si may originate from these silicon compounds other than silicon oxide.

[0038] The individual particles contained in the molding powder, which are independent of each other, may be composite particles such as a sintered body of multiple particles (sintered particles), and may be amorphous or crystalline. In this embodiment, when a powder is said to consist of multiple compounds, it includes cases where multiple types of particles made of one type of compound are mixed together, and cases where one or multiple types of particles made of multiple types of compounds are mixed together. Hereafter, to avoid confusion, the independent particles contained in the powder will be simply called particles, and the particles that make up each individual particle will be called constituent particles. For example, when Al2O3 particles and Y2O3 particles are sintered to form a composite particle, it can be said that the particle contains constituent particles of Al2O3 and constituent particles of Y2O3. Alternatively, it can be said that the particle contains regions of Al2O3 and regions of Y2O3.

[0039] An example of a molding powder in which each particle contains one type of compound is a molding powder containing Al, Y, and Si as elements, which is a mixture of three types of particles: Al2O3 particles, Y2O3 particles, and SiO particles.

[0040] Examples of particles constituting the molding powder containing multiple compounds include a state in which a single particle is composed of an Al2O3 region, a Y2O3 region, and an SiO region, or a state in which a particle consisting of an Al2O3 region, a Y2O3 region, and a particle consisting of SiO is included.

[0041] In powder bed fusion fusion, when forming a powder bed layer using a recoater, and in cladding, when spraying powder from a nozzle, it is important that the molding powder has suitable fluidity for these processes. Therefore, it is preferable that the molding powder of this embodiment satisfies a fluidity index of 40 [sec / 50g] or less. To ensure such fluidity, it is preferable that each particle is spherical, but the particle shape is not limited to spherical as long as the above fluidity index is satisfied. The fluidity index can be measured, for example, in accordance with JIS Z 2502. The angle of repose can also be used as an index of fluidity. It is preferable that the molding powder of this embodiment satisfies an angle of repose of 40° or less. The angle of repose can be measured in accordance with JIS R 9301-2-2.

[0042] It is preferable that SiO, which functions as an absorbent, is included as SiO-containing particles in which 50 mol% or more of the particles are SiO, regardless of the state in which other compounds are contained in the molding powder. Even if the particles contain SiO and other compounds, as long as 50 mol% or less of the particles are SiO, they can still function as an absorbent. Furthermore, it is particularly preferable that the functional SiO is contained as particles (SiO particles) independent of other components, regardless of the state in which other compounds are contained in the molding powder.

[0043] When SiO is contained as independent SiO particles, a higher light absorption capacity can be achieved compared to when SiO is contained within a single particle along with other compounds. Furthermore, the laser light can more easily reach the absorber, allowing for efficient utilization of the absorber's light absorption capacity. In addition, if SiO is contained as independent SiO particles, the particle size of the SiO particles and the particle sizes of the other particles can be adjusted separately, making it easier to control the flowability of the powder and to control the amount of absorber present within the spot diameter of the irradiated laser beam. This point will be explained in detail later.

[0044] When silicon monoxide (SiO)-containing particles are SiO particles that do not contain regions other than silicon monoxide, the average particle size of the oxide particles other than silicon oxide particles (hereinafter also referred to as base material particles) is preferably 5 μm or larger and greater than the average particle size of the SiO particles, from the viewpoint of achieving desirable fluidity. The average particle size of the base material particles is more preferably 10 μm or more and 200 μm or less. Furthermore, the average particle size of the base material particles is preferably 2 times or more the average particle size of the SiO particles, and also preferably 3 times or more. Furthermore, the average particle size of the base material particles is preferably 10 times or less the average particle size of the SiO particles, and more preferably 8 times or less. If the average particle size of the SiO particles is less than 5 μm, the average particle size of the base material particles may be 5 times or more the average particle size of the SiO particles. If the average particle size of the SiO particles is 5 μm or more, the average particle size of the base material particles may be 5 times or less the average particle size of the SiO particles. Furthermore, from the viewpoint of achieving high molding accuracy and the ease with which the powder can be sintered or melted, the average particle size of the base material particles is preferably 200 μm or less, and more preferably 150 μm or less. From the viewpoint of the ease with which the powder can be melted, the average particle size of the base material particles is more preferably 100 μm or less, and even more preferably 50 μm or less. The average particle size of the base material particles may be 20 μm or more, or 40 μm or less.

[0045] When silicon monoxide (SiO)-containing particles are SiO particles that do not contain regions other than silicon monoxide, the average particle size of the SiO particles is preferably 10 μm or less, and preferably smaller than the average particle size of the base material particles. When the SiO particles satisfy this condition, the probability of multiple SiO particles being dispersed in the vicinity of the base material particles increases, so that the heat generated by the absorption of laser light by SiO is efficiently transferred to the base material particles, making it easier for the powder in the laser light irradiation area to melt. Considering the dispersibility of SiO in the molding powder and the realization of high packing density, it is preferable that the average particle size of the SiO particles be as small as possible. On the other hand, if the average particle size of the SiO particles is 1 μm or more, scattering into the atmosphere due to laser light irradiation is suppressed, and a suitable amount as an absorber can be maintained in the molding powder. For this reason, 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, more preferably 0.5 μm or more and 10 μm or less, and more preferably 1 μm or more and 10 μm or less. The average particle size of the SiO particles is preferably 1 / 2 or less of the average particle size of the base material particles, and also preferably 1 / 3 or less. The average particle size of the SiO particles is preferably 1 / 10 or more of the average particle size of the base material particles, and more preferably 1 / 8 or more. If the average particle size of the SiO particles is 1 μm or more and less than 5 μm, it is more preferable that the average particle size of the SiO particles is 1 / 5 or less of the average particle size of the base material particles. If the average particle size of the SiO particles is 5 μm or more and 10 μm or less, the average particle size of the SiO particles may be 1 / 5 or more of the average particle size of the base material particles.

[0046] When silicon monoxide (SiO)-containing particles include regions other than silicon monoxide, these particles are referred to as composite SiO particles. From the viewpoint of achieving fluidity suitable for additive manufacturing, the average particle size of composite SiO particles is preferably 5 μm to 200 μm. Furthermore, it is preferable that the average particle size of composite SiO particles is greater than the average diameter of the regions consisting of SiO contained in the composite SiO particles. For example, the average particle size of composite SiO particles may be twice or more the average diameter of the regions consisting of SiO contained in the composite SiO particles. A preferred average particle size of composite SiO particles is 5 μm or more, but a more preferred average particle size of composite SiO particles is 10 μm or more. A further preferred average particle size of composite SiO particles is five times or more the average diameter of the regions consisting of SiO contained in the composite SiO particles. From the viewpoint of achieving high molding accuracy and ease of sintering or melting of the powder, when silicon monoxide (SiO)-containing particles include regions other than silicon monoxide, the average particle size of the silicon monoxide-containing particles is preferably 200 μm or less, and more preferably 150 μm or less. From the viewpoint of ease of melting the powder, the average particle size of the composite SiO particles is more preferably 100 μm or less, and even more preferably 50 μm or less.

[0047] In SiO-containing particles that include both SiO and other compounds, the average particle size of the constituent particles made of SiO is determined by observing the powder with a scanning electron microscope (SEM), measuring the area of ​​the SiO-containing regions, and calculating the equivalent circular diameter of that area. Measurements are taken for multiple (100 or more) SiO-containing regions, and the median value is taken as the average particle size of the constituent particles made of SiO.

[0048] In this embodiment, particle size refers to the equivalent circular diameter (Heywood diameter) of each individual particle. The average particle size of particles with a specific composition contained in the molding powder does not refer to the particle size of individual particles, but rather to the median value of a group of particles having the same composition, and does not mean that particles other than the size indicated as the average particle size are not contained in the powder.

[0049] The average particle size can be calculated in the same way as the average particle size of its constituent particles, using the following method: Observe the powder using a scanning electron microscope (SEM), measure the area of ​​particles containing the specific composition for which the average particle size is to be calculated, and calculate the equivalent circular diameter of that area. This method for calculating the average particle size can be applied regardless of the state of the particles.

[0050] The molding powder of this embodiment preferably does not contain a resin binder. This is because the resin binder has a significantly lower melting point compared to other compounds contained in the powder, and therefore may burn off with a large impact when irradiated with laser light, potentially causing voids and defects in the molded area.

[0051] Furthermore, if the powder contains elemental carbon, which is sublimable, the carbon may combine with oxygen and escape as a gas, potentially leaving voids in the volume previously occupied by the elemental carbon. In addition, elemental carbon may sublimate and rapidly gasify upon irradiation with laser light, potentially adversely affecting the molding process. Specifically, rapid gasification may cause stress on the molten and solidified parts of the molding powder, potentially resulting in a deformed object. Therefore, it is preferable that the powder substantially contains no elemental carbon. However, the ratio of carbon atoms to metal elements in the multiple compounds contained in the powder should be 1000 ppm or less in molar ratio.

[0052] The molding powder in this embodiment may be crystalline, amorphous, or a mixture thereof. Furthermore, it is not necessary for the composition of the powder and the molded ceramic object to be perfectly identical; differences in oxidation state, nitridation state, etc., are acceptable.

[0053] <Method for manufacturing ceramic molded objects> As one embodiment, the present invention provides a method for manufacturing ceramic molded objects (ceramic structures). In the method for manufacturing ceramic molded objects of this embodiment, a molded object is formed by heating a material using the ceramic molding powder of the present invention with light, and the heating is characterized in that at least one type of oxide particle is melted. The manufacturing method of this embodiment is suitably used in additive manufacturing, in which a shaping powder is irradiated with laser light according to slice data generated based on three-dimensional data of the ceramic object to be manufactured. Specifically, the manufacturing method of this embodiment is suitably used in manufacturing methods using powder bed fusion or cladding. The manufacturing process involves alternating between the following placement step and irradiation step multiple times to produce the ceramic object.

[0054] In the placement step, oxide particles are placed on a base, and in the irradiation step, laser light is irradiated onto part or all of the oxide particles to melt and solidify the oxide particles in the areas irradiated with the laser light, thereby obtaining an intermediate fabricated object.

[0055] When fabrication is performed using the powder bed fusion method, the placement step and irradiation step are performed by spreading the above-mentioned fabrication powder onto the substrate to a predetermined thickness and then irradiating it with laser light. When fabrication is performed using the cladding method, the placement step and irradiation step are performed by ejecting the fabrication powder of the present invention to predetermined locations and irradiating those predetermined locations with laser light.

[0056] There are no restrictions on the wavelength of the laser light used for fabrication, but it is preferable to use one that has been adjusted to a desired focal size, such as 10 μm to 2 mm in diameter, using lenses or fibers. The focal size is one of the parameters that affects fabrication accuracy, and in order to achieve a fabrication accuracy of 100 μm (0.1 mm), depending on the situation, it is preferable that the line width of the laser light is about the same as the fabrication accuracy, and that the focal size of the laser light diameter is 100 μm or less. It does not matter whether the laser light irradiation is continuous or pulsed. As for the laser light, for example, laser light with a wavelength around 1000 nm from an Nd:YAG laser or a Yb fiber laser can be suitably used. This is because the SiO component shows particularly high absorption ability for light with a wavelength of about 1 μm.

[0057] Figures 1A to 1H are conceptual diagrams of a three-dimensional fabrication apparatus using powder bed fusion (infrared laser fusion). The basic fabrication flow of the infrared laser fusion method, which can use the fabrication powder of the present invention, will be explained using the schematic diagrams in Figures 1A to 1H.

[0058] As shown in Figure 1A, first, raw material powder 101 is placed on a base 130 installed on a stage 151, and then spread to a predetermined thickness with a roller 152 to form a powder layer 102 as shown in Figure 1B. As shown in Figure 1C, laser light emitted from a laser light source 180 is irradiated onto the powder layer 102 while scanning with a scanner unit 181 based on slice data generated from the shape data of a desired three-dimensional model. Within the irradiation range of the laser light, the raw material powder melts and then solidifies, forming a solidified section 100 corresponding to the slice data for one layer. Subsequently, as shown in Figure 1D, the stage 151 is lowered to form a new powder layer 102 on top of the solidified section 100, and as shown in Figure 1E, laser light is irradiated based on the slice data. As shown in Figure 1F, this series of steps is repeated a number of times according to the slice data to obtain a fabricated object 110. 103 indicates unsolidified raw material powder. Finally, as shown in Figure 1G, the unsolidified raw material powder 103 is removed, and as necessary, unnecessary parts of the molded object 110 are removed or the molded object 110 is separated from the base 130, as shown in Figure 1H. Furthermore, heat treatment may be performed thereafter if necessary.

[0059] The cladding method will be explained using Figure 2. The cladding method is a technique in which powder is ejected from multiple powder supply holes 202 in a cladding nozzle 201, and a laser beam 203 is irradiated onto the area where the powder converges, thereby sequentially creating ceramic objects in the desired location. A key feature of this method is its ability to create objects on curved surfaces.

[0060] Furthermore, the atmosphere may be controlled during the manufacturing process. In the manufacturing process, it is preferable to use not only an atmospheric atmosphere, but also an inert atmosphere containing nitrogen or noble gases, an atmosphere containing hydrogen, or a reduced-pressure atmosphere, which are environments that facilitate the reduction of compounds contained in the molding powder, or an oxygen atmosphere. By controlling the atmosphere in this way, it becomes possible to use powders containing compounds in an oxidized or reduced state relative to the stoichiometric ratio in the manufacture of ceramic molded objects.

[0061] In the manufacturing process of this embodiment as described above, by using the molding powder of the present invention, it is possible to obtain ceramic molded objects that enable stable molding and ensure molding accuracy.

[0062] The ceramic molded objects produced using the molding powder of this embodiment are not limited to those made of inorganic material in a crystalline state. If the desired physical properties can be obtained, part or more of the material may be in an amorphous state. Furthermore, the above manufacturing process may produce ceramic molded objects that include regions close to a metallic state, in which the molding powder is reduced.

[0063] The method for manufacturing ceramic molded objects according to this embodiment may include a heating step in addition to a molding step in which an intermediate molded object is obtained from a powder material, and the heating step can repair cracks present in the intermediate molded object.

[0064] When powder is melted by irradiation with an energy beam such as laser light, it cools and solidifies by releasing heat into the surroundings, forming an intermediate structure.

[0065] In the case of ceramics, the thermal diffusivity is lower compared to metals, so the temperature difference between the molten area and the surrounding temperature is relatively large. Therefore, when fabrication is performed by infrared laser melting without high-temperature preheating, many microcracks occur in the intermediate fabricated object. Microcracks are distributed throughout the entire intermediate fabricated object (surface and interior). When the cross-section of the intermediate fabricated object is examined with a scanning electron microscope, most of the microcracks are several nanometers to several micrometers wide. The length of the microcracks varies from several micrometers to several millimeters. Microcracks formed in intermediate molded objects cause stress to concentrate near the cracks when the object is subjected to stress, resulting in a decrease in mechanical strength compared to the bulk material. Therefore, it is preferable to repair microcracks by some method.

[0066] As an example of the molding powder of the present invention, a ceramic molding powder mainly consisting of Al2O3 particles, Y2O3 particles, and SiO particles can be cited. In such a powder, microcracks are self-repaired during the firing process after the intermediate molded object is fabricated using the method described above. Within the intermediate molded object formed by additive manufacturing, which involves irradiating this molding powder with laser light, regions mainly composed of Y, regions mainly composed of Si, and regions containing both Y and Si are locally formed. In the heat treatment process performed after the formation of the intermediate molded object, the aforementioned regions soften or melt due to the heat treatment, penetrate into the microcracks, and fill the inside of the microcracks, thereby repairing the cracks. The heat treatment temperature at this time should be 1600°C or higher, preferably in the range of 1650°C to 1850°C.

[0067] In the manufacturing of ceramic molded objects, the elemental ratio Y / Si (molar ratio) in the oxide structure is important for ensuring sufficient mechanical strength and chemical resistance while also providing repairability for cracks in the intermediate molded object. Through the heating process described above, regions containing Y, regions containing Si, or regions containing both Y and Si in the intermediate molded object form compounds such as Y2Si2O7 or Y2SiO5, which soften or melt, penetrate and fill the cracks, and repair the cracks with these Y and Si-containing compounds. The repaired regions are composed of Y and Si-containing compounds, preventing a decrease in the mechanical properties and chemical resistance of the ceramic structure caused by these regions, compared to regions where silicon oxide is the main component. This effect can be achieved when the elemental ratio of Y to Si is 25 / 75 ≤ Y / Si ≤ 95 / 5. The lower limit of the Y content in the elemental ratio of Y to Si is a favorable condition for the crack repair regions to become Y and Si-containing compounds. If the amount of Y is insufficient relative to Si, regions mainly composed of silicon oxide may remain in the structure, potentially leading to a decrease in mechanical properties and chemical resistance. Furthermore, the upper limit of the Y amount is a favorable condition for adequately repairing cracks in the fabricated object. If the amount of Si is insufficient, regions where cracks cannot be repaired may remain in the fabricated object, potentially resulting in a decrease in mechanical properties.

[0068] Furthermore, before the heating process, it is possible to take advantage of the presence of fine cracks and impregnate these areas with a functional modification material. For example, it is possible to impregnate the material with a metal element-containing liquid containing Li, Na, K, Mg, Ca, Y, Al, Ti, Zr, Hf, Si, etc., and then dry or fix it at a temperature of 600°C or lower. In this way, the three-point bending strength of the ceramic molded object can be further increased.

[0069] <Ceramic Structures> As one embodiment, the present invention provides a ceramic structure. Furthermore, the ceramic structure of this embodiment includes a molded object produced by the molding powder of the present invention or by the method for manufacturing a ceramic molded object of the present invention. The ceramic structure of this embodiment contains at least Al, Y, and Si, and the elemental ratio Y / Si satisfies 25 / 75 ≤ Y / Si ≤ 95 / 5.

[0070] The ceramic structure of this embodiment has a function to repair cracks and fractures. For example, if the ceramic structure fractures due to external force during use, it has a self-repairing function that allows the fractured parts to be realigned and heated again, restoring the ceramic structure to the same level as its original mechanical strength. The heat treatment temperature at this time should be 1600°C or higher, preferably in the range of 1600°C to 1850°C, and more preferably in the range of 1650°C to 1790°C. This feature is an effect obtained by the fact that the ceramic structure of this embodiment has 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. The presence of these regions allows compounds such as Y2Si2O7 and Y2SiO5 to be formed by heating, which soften or melt, penetrate into the cracks and fill or fill the fractured parts, and are repaired by compounds containing Y and Si. The repaired area is a compound containing Y and Si, which prevents a decrease in the mechanical properties and chemical resistance of the ceramic structure caused by this area, compared to when the area is mainly composed of silicon oxide. The lower limit of the Y content in the elemental ratio of Y to Si is a favorable condition for the above-mentioned crack repair area to become a compound containing Y and Si. If the amount of Y is insufficient relative to Si, areas mainly composed of silicon oxide will remain in the structure, which may cause a decrease in mechanical properties and chemical resistance. Conversely, the upper limit of the Y content is a favorable condition for adequately repairing cracks or fractures in the fabricated object. If the amount of Si is insufficient, areas where cracks or fractures in the fabricated object cannot be repaired will remain, which may cause a decrease in mechanical properties.

[0071] In the ceramic structure of this embodiment, Y / Si more preferably satisfies 1.0 ≤ Y / Si ≤ 10.0. Furthermore, in the ceramic structure of this embodiment, it is preferable that at least one of the following conditions is met: Al is greater than Y in mole fraction, and Al is greater than Si. Furthermore, it is preferable that the ceramic structure of this embodiment contains Zr. This further enhances the mechanical strength of the ceramic structure. More preferably, the composition of the ceramic structure contains 3 mol% or more of Zr in terms of oxide, and more preferably 7 mol% or more. If Zr is included, it is preferable that the ceramic structure of this embodiment satisfies at least one of the following conditions: Al is greater than Zr, Y is greater than Zr, and Zr is greater than Si.

[0072] Furthermore, it is preferable that the Al contained in the ceramic structure of this embodiment is present in an oxide equivalent of 50 mol% or more in the composition of the ceramic structure. This further enhances the mechanical strength and chemical resistance of the ceramic structure. More preferably, it is preferable to have 60 mol% or more, more preferably 70 mol% or more, and even more preferably 80 mol% or more. However, in the ceramic structure of this embodiment, the mole fraction of Zr may be higher than the mole fraction of Al. In this embodiment, the Y contained in the ceramic structure is preferably contained as a complex oxide. This further enhances the mechanical strength, chemical resistance, and plasma resistance of the ceramic structure. The ceramic structure preferably contains an oxide containing Y and Al. An oxide containing Y and Al refers to a complex oxide mainly composed of Y and Al. While there are no limitations on the ratio of Y to Al in the oxide containing Y and Al, Y3Al5O is preferable. 12 YAlO3 and Y4Al2O9 are cited as preferred examples. Ceramic structures are Y3Al5O 12It is preferable to include these because it can enhance mechanical strength and chemical resistance. Furthermore, it is preferable for the ceramic structure to contain YAlO3 or Y4Al2O9 because it can enhance mechanical strength and plasma resistance. The oxide containing Y and Al preferably contains at least one of YAlO3 and Y4Al2O9. Normally, oxides containing Y and Al form only a stable phase depending on the ratio of Y and Al. However, when fabricated using energy beam irradiation such as laser light, localized heating can lead to the formation of a non-uniform structure within the ceramic structure, and rapid solidification can cause changes in phase morphology, resulting in the formation of multiple phases of Y and Al oxides, including a metastable phase, within the ceramic structure. Furthermore, it is preferable that the Si contained in the ceramic structure of this embodiment is contained as a complex oxide. This further enhances the mechanical strength and chemical resistance of the ceramic structure. More preferably, the ceramic structure contains an oxide containing Y and Si. An oxide containing Y and Si refers to a complex oxide mainly composed of Y and Si. The ceramic structure of this embodiment may contain an oxide containing Y and Al, and an oxide containing Y and Si. In this case, it is preferable that the volume of the oxide containing Y and Al in the ceramic structure is greater than the volume of the oxide containing Y and Si. By doing so, the mechanical strength and chemical resistance of the ceramic structure can be further enhanced. The ceramic structure of this embodiment has a density of 4.19 [g / cm³] 3 It is preferable that it be less than or equal to the following: Furthermore, it is preferable that the ceramic structure of this embodiment has a three-point bending strength of 152 [MPa] or more. Furthermore, the ceramic structure of this embodiment has a three-point bending strength [MPa] / density [g / cm³]. 3 ] is 40 [MPa·cm 3 It is preferable that it is 1 / g or more.

[0073] <Application Examples> As one embodiment, the present invention provides a device that is an application example of the ceramic powder of the present invention. The device as an application example comprises a ceramic molded object and at least one of electrical components, optical components, metal components, and resin components.

[0074] Various devices can be constructed by combining a mechanical part, which is a ceramic molded object, with at least one of electrical parts, optical parts, metal parts, and resin parts. The mechanical part may be, for example, a link part used as a hand or arm, but it may also be a transmission part such as a gear, cam, or shaft, or a coupling part such as a screw. The mechanical part of this embodiment can also be used as a heat-resistant or fire-resistant part. Devices equipped with mechanical parts may be printing equipment or office equipment such as inkjet printers, laser printers, scanners, copiers, and multifunction printers. Devices may be imaging equipment such as cameras, displays, and projectors. Devices may be optical equipment such as interchangeable lenses and binoculars. Devices may be medical equipment such as X-ray machines, CT scanners, MRI scanners, and endoscopes. Devices may be industrial equipment such as exposure equipment, film deposition equipment, generators, and robots. Devices may be various types of mobile or transportation equipment such as automobiles, aircraft, and ships. Devices may also be scientific equipment such as nuclear reactors (fusion reactors, fission reactors) and accelerators, or space equipment such as artificial satellites. [Examples]

[0075] Figures 3A to 3E show a list of examples and comparative examples of the present invention. Figure 3A shows the composition of the molding powder in mole fraction. Figure 3B shows the composition of the molding powder in mass fraction. Figure 3C shows the particle size and angle of repose of the molding powder (measured in accordance with JIS R9301-2-2). Figure 3D shows the elemental ratios of various elements and the molar ratio of oxides in the molding powder. Figure 3E shows the firing temperature, firing time, density, relative density, three-point bending strength (measured in accordance with JIS R1601), crack self-repairing properties, alkali dissolution mass loss (measurement results of alkali resistance by the method described later), and strength / density.

[0076] (Example 1) The median particle size is approximately 20 μm and the density is 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 prepared. For every 10g of Al2O3 particles, 2.2g of Y2O3 particles and 0.18g of SiO particles were weighed and placed in a 1L poly container up to 70% capacity. φ5mm zirconia beads were added, and the mixture was blended in a roller mixer for 30 minutes to obtain a powder with the composition ratio shown in Figure 3A. The angle of repose of the powder was 34.7°, confirming good fluidity. This powder composition contains Al, Y, and Si as oxide particles, with a molar ratio of Y to Si of 83 / 17, satisfying the preferred composition range of the present invention.

[0077] For the infrared laser melting method, a 3D Systems ProXDMP100 was used to fabricate an intermediate object with dimensions of 5 mm wide x 5 mm thick x 38 mm long as a precursor to the ceramic object. This was done with a layer thickness of 20 μm, laser power of 45 W, scan speed of 100 mm / sec, and scan pitch of 140 μm.

[0078] The fabricated intermediate structure was subjected to heat treatment at a maximum temperature of 1700°C for 20 minutes. Figure 4A shows the SEM observation image of the obtained structure and the elemental mapping images of Al, Y, Si, and O obtained by SEM-EDX evaluation. Regions consisting mainly of Al oxide, regions consisting mainly of Y and Al oxide, and regions consisting mainly of Y and Si oxide were observed. From the SEM observation image and elemental mapping image, the areas of the region consisting mainly of Y and Al oxide and the region consisting mainly of Y and Si oxide were calculated, and the volume of each region in the structure was roughly evaluated. The region consisting mainly of Y and Si oxide accounted for 5.9% of the total volume of the field of view, while the region consisting mainly of Y and Al oxide accounted for 28.6% of the total volume, which was larger than the region consisting mainly of Y and Si oxide. This satisfies the preferred configuration of the present invention. Furthermore, the region consisting mainly of Y and Al was found to be Y3Al5O from the semi-quantitative composition ratio obtained by SEM-EDX evaluation.12 It was confirmed that it contains regions of YAlO3 and Y4Al2O9.

[0079] The resulting structure showed a repaired crack area and a three-point bending strength of 173 MPa. Furthermore, for the specimen that fractured into two pieces in the three-point bending strength test, the fractured area was repaired and it was confirmed that the fractured portion had jointability by placing the two fracture surfaces together and repeating the same process as the heat treatment described above.

[0080] Furthermore, alkali resistance measurements were performed on the obtained structures. The measurements were conducted using the ETHOS PRO measuring instrument from Milestone General. The samples were immersed in a 20% by mass NaOH alkaline solution, heated to 200°C, and held for 40 minutes. The change in mass per unit area of ​​the sample before and after treatment was evaluated. For reference, the alkali resistance of typical alumina materials in equivalent tests is 2.6 g / m² in terms of change in mass per unit area. 2 It is approximately 3.2 g / m². The mass change per unit area in this embodiment is 3.2 g / m². 2 It exhibited comparable alkali resistance to alumina materials, demonstrating good alkali resistance. The strength / density was 46 MPa·cm². 3 It was lightweight and durable, weighing [weight in grams].

[0081] (Examples 2-4) From Example 1, only the particle mixing ratio was changed, and a powder mixture was prepared in the quantities shown in Figure 3A. Using the same molding apparatus and conditions as in Example 1, the same shape was fabricated and subjected to the same heat treatment. The structures obtained in Examples 1-4 showed repaired crack areas, and all three-point bending strengths were high, exceeding 150 MPa. The strength / density ratio was 40 MPa·cm² in all cases. 3 It weighed over [number] grams, and was sufficiently light and durable.

[0082] (Discussion regarding Examples 1-4, 13, and 16) Instead of using Examples 1-4, the powder configurations of Examples 13 and 16 can also be adopted. The powder configurations of Examples 1-4, 13, and 16 satisfy the following conditions. It contains Al, Y, and Si, and the molar ratio of Y to Si satisfies 25 / 75 ≤ Y / Si ≤ 95 / 5. The composition satisfies the elemental ratio Al / Y of Al to Y being between 4.60 and 73.78, and the elemental ratio Al / Si being between 21.60 and 87.45. It contains 50 mol% or more of aluminum oxide, 1.29 mol% to 15.02 mol% of yttrium oxide, and 1.90 mol% to 7.18 mol% of silicon oxide.

[0083] Furthermore, the ceramic fabricated objects obtained in Examples 1-4, 13, and 16 satisfy the following conditions. It contains Al, Y, and Si, and the elemental ratio Y / Si satisfies 25 / 75 ≤ Y / Si ≤ 95 / 5. The elemental ratio of Al to Y, Al / Y, is between 4.60 and 73.78, and the elemental ratio of Al to Si, Al / Si, is between 15.53 and 140.35. It contains 50 mol% or more of aluminum oxide, 1.29 mol% to 15.02 mol% of yttrium oxide, and 1.90 mol% to 7.18 mol% of silicon oxide.

[0084] Furthermore, the ceramic fabricated objects obtained in Examples 1 to 4 all satisfied the following condition: namely, a density of 4.19 [g / cm³]. 3 The three-point bending strength was 152 [MPa] or less. Three-point bending strength [MPa] / Density [g / cm³] 3 ] is 40 [MPa·cm 3 It was above [g].

[0085] (Example 5) To increase strength, the powder from Example 1 was modified to the amount shown in Figure 3A, with a median particle size of approximately 30 μm and a density of 5.7 g / cm³. 3Yttrium-stabilized zirconia 3YSZ particles (ZrO2 particles with 3 mol% Y2O3 added) were mixed in the same manner as other particles. The angle of repose of the powder was 35.9°, and good fluidity was confirmed. This powder satisfies the suitable composition range, similar to Example 1. Using this powder, the same shape was fabricated using the same fabrication apparatus and fabrication conditions as in Example 1, and the same heat treatment was performed. Figure 4B shows the SEM observation image of the obtained structure and the elemental mapping images of Al, Y, Zr, Si, and O obtained by SEM-EDX evaluation. Regions consisting mainly of Al oxides, regions consisting mainly of Y and Al oxides, regions consisting mainly of Zr and Y oxides, and regions consisting mainly of Y and Si oxides were observed. From the SEM observation image and elemental mapping image, the areas of the regions consisting mainly of Y and Al oxides and the regions consisting mainly of Y and Si oxides were calculated, and the volume of each region in the structure was evaluated in a simple manner. The region consisting mainly of Y and Si oxides accounted for 4.9% of the total volume of the field of view, while the region consisting mainly of Y and Al oxides accounted for 12.7% of the total volume, which was larger than the region consisting mainly of Y and Si oxides. This satisfies the preferred configuration of the present invention. Furthermore, the region consisting mainly of Y and Al oxides was found to be Y3Al5O based on the composition ratio of semi-quantitative values ​​obtained by SEM-EDX evaluation. 12 It was confirmed that it contains regions of YAlO3 and Y4Al2O9.

[0086] The resulting structure showed repaired crack areas and exhibited a high three-point bending strength of over 200 MPa. Furthermore, for specimens that fractured into two pieces during the three-point bending strength test, the fractured areas were repaired and bondability to the fractured portion was confirmed by placing the two fracture surfaces together and repeating the same process as the heat treatment described above. Furthermore, alkali resistance was measured on the obtained structure using 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 3.4 g / m². 2 It exhibited comparable alkali resistance to alumina materials, demonstrating good alkali resistance. The strength / density was 55 MPa·cm². 3It was lightweight and durable, weighing [weight in grams].

[0087] (Examples 6-12) From Example 5, only the particle mixing ratio was changed, and powder was prepared in the quantities shown in Figure 3A. The same shape was fabricated using the same molding apparatus and conditions as in Example 1, and the same heat treatment was performed. The structures obtained in Examples 6 to 12 were in a state where the crack areas had been repaired, and the three-point bending strength was high in all cases, exceeding 150 MPa. The strength / density was 40 MPa·cm in all cases. 3 It weighed over [number] grams, and was sufficiently light and durable.

[0088] (Considerations regarding Examples 5-12, 14, 15, 17, 18, and 21) Instead of using the powder configurations in Examples 6-12, the powder configurations in Examples 14, 15, 17, 18, and 21 can also be used. The powder configurations in Examples 5-12, 14, 15, 17, 18, and 21 satisfy the following conditions. It contains Al, Y, and Si, and the molar ratio of Y to Si satisfies 25 / 75 ≤ Y / Si ≤ 95 / 5. The composition satisfies the elemental ratio Al / Y of Al to Y being between 4.60 and 73.78, and the elemental ratio Al / Si being between 21.60 and 87.45. The composition satisfies the following ranges: Al / Zr (elemental ratio of Al to Zr) is between 9.89 and 44.58; Y / Zr (elemental ratio of Y to Zr) is between 0.18 and 7.64; and Zr / Si (elemental ratio of Zr to Si) is between 0.55 and 7.35. It contains 50 mol% or more of aluminum oxide, 1.29 mol% to 15.02 mol% of yttrium oxide, and 1.90 mol% to 7.18 mol% of silicon oxide. It contains zirconium oxide in an amount of 3.93 mol% to 13.97 mol%.

[0089] (Examples 22-26) From Example 5, only the particle size was changed, and powders were prepared by mixing them in the quantities shown in Figure 3A. The angle of repose of the powders was 40° or less in all cases, and good fluidity was confirmed. The same shape was fabricated using the same molding apparatus and molding conditions as in Example 1, and the same heat treatment was performed. The structures obtained in Examples 22 to 26 were in a state where the crack areas had been repaired, and the three-point bending strength was a high value of 150 MPa or more in all cases. The strength / density was 40 MPa·cm in all cases. 3 It weighed over [number] grams, and was sufficiently light and durable.

[0090] Furthermore, the ceramic fabricated objects obtained in Examples 5-12, 14, 15, and 17-26 satisfy the following conditions. It contains Al, Y, and Si, and the elemental ratio Y / Si satisfies 25 / 75 ≤ Y / Si ≤ 95 / 5. The elemental ratio of Al to Y, Al / Y, is between 4.60 and 73.78, and the elemental ratio of Al to Si, Al / Si, is between 15.53 and 140.35. The elemental ratio of Al to Zr, Al / Zr, is between 9.89 and 44.58; the elemental ratio of Y to Zr, Y / Zr, is between 0.18 and 7.64; and the elemental ratio of Zr to Si, Zr / Si, is between 0.55 and 7.35. It contains 50 mol% or more of aluminum oxide, 1.29 mol% to 15.02 mol% or less of yttrium oxide, 1.90 mol% to 7.18 mol% or less of silicon oxide, and 3.93 mol% to 13.97 mol% or less of zirconium oxide.

[0091] Furthermore, the ceramic fabricated objects obtained in Examples 5-12 and 22-26 satisfied the following condition: namely, a density of 4.19 [g / cm³]. 3 The three-point bending strength was 152 [MPa] or less. Three-point bending strength [MPa] / Density [g / cm³] 3 ] is 40 [MPa·cm 3 It was above [g].

[0092] (Comparative Example 1) The median particle size is approximately 20 μm and the density is 3.9 g / cm³. 3The Al2O3 particles have a median particle size of approximately 30 μm and a density of 5.7 g / cm³. 3 Yttrium-stabilized zirconia 3YSZ particles, median particle size approximately 4 μm, density 2.1 g / cm³ 3 SiO particles were prepared and mixed in the quantities shown in Figure 3A. This powder composition has a molar ratio of Y to Si of 0.15 / 0.85, which is an example of a situation that does not satisfy the preferred composition range of the present invention. The same shape was fabricated using the same fabrication apparatus and fabrication conditions as in Example 1. The heat treatment was performed with the maximum temperature changed to 1790°C. The resulting structure had insufficient repair of the crack region, and the three-point bending strength was a low value of 61 MPa. The strength / density was 15 MPa·cm. 3 It weighed [number] grams, so it wasn't exactly light and durable.

[0093] (Comparative Example 2) The median particle size is approximately 20 μm and the density is 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 TiO particles with a median particle size of approximately 30 μm were prepared and mixed in the quantities shown in Figure 3A. This powder composition has a molar ratio of Y to Si of 1.00 / 0.00, which is an example of a situation that does not satisfy the preferred composition range of the present invention. The same shape was fabricated using the same fabrication apparatus and fabrication conditions as in Example 1, and the same heat treatment was performed. The resulting structure had insufficient repair of crack areas, and the three-point bending strength was a low value of 64 MPa. The strength / density was 17 MPa·cm. 3 It was / g, and could not be described as light and durable.

[0094] (Comparative Example 3) The median particle size is approximately 20 μm and the density is 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 These are SiO2 particles with a median particle size of approximately 4 μm and a density of 2.1 g / cm³. 3SiO particles were prepared and mixed in the quantities shown in Figure 3A. This powder composition has a molar ratio of Y to Si of 0.00 / 1.00, which is an example of a situation that does not satisfy the preferred composition range of the present invention. The same shape was fabricated using the same fabrication apparatus and fabrication conditions as in Example 1, and heat treatment was performed by changing the maximum temperature to 1690°C. The obtained structure had the crack region repaired, and the three-point bending strength was 103 MPa. Furthermore, alkali resistance was measured on the obtained structure using 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 value is more than 100 times that of alumina material, confirming that it has inferior alkali resistance. [Industrial applicability]

[0095] According to this embodiment, using a direct fabrication method (powder bed fusion method or infrared laser fusion method), a mechanical strength of 150 MPa or more, and even 200 MPa or more, can be achieved, and alkali resistance can be 10 g / m² in terms of mass loss per unit area. 2 Furthermore, 5g / m 2 The following can be achieved, and a ceramic molded product with even finer crack repairability can be provided.

[0096] This embodiment includes the following configurations and methods. (Composition 1) A powder for ceramic molding containing one or more types of oxide particles, It contains at least Al, Y, and Si, and the elemental ratio of Y to Si is Y / Si A powder characterized by satisfying the conditions 25 / 75 ≤ Y / Si ≤ 95 / 5. (Configuration 2) The powder according to configuration 1, satisfying that Y / Si ≥ 1.0. (Composition 3) The powder according to configuration 1 or 2, satisfying that Y / Si ≤ 10.0. (Composition 4) Al is greater than Y, and Al is more abundant than Si. A powder according to any one of items 1 to 3, satisfying at least one of the following conditions. (Composition 5) The elemental ratio of Al to Y, Al / Y, is between 4.60 and 73.78, and The elemental ratio of Al to Si (Al / Si) must be between 21.60 and 87.45. A powder according to any one of items 1 to 4, satisfying at least one of the following conditions. (Composition 6) Furthermore, the powder according to any one of items 1 to 5, which also contains Zr. (Composition 7) Al is more abundant than Zr. Y is greater than Zr, and The fact that Zr is more abundant than Si, The powder described in configuration 6, satisfying at least one of the following conditions. (Composition 8) The elemental ratio of Al to Zr (Al / Zr) must be between 9.89 and 44.58. The elemental ratio of Y to Zr, Y / Zr, is between 0.18 and 7.64, and The elemental ratio of Zr to Si, Zr / Si, must be between 0.55 and 7.35. The powder according to composition 6 or 7, satisfying at least one of the following conditions. (Composition 9) A powder containing silicon monoxide, as described in any one of items 1 to 8. (Composition 10) The powder according to any one of items 1 to 9, wherein the one or more oxide particles include aluminum oxide particles and silicon oxide particles. (Composition 11) The powder according to configuration 10, wherein the silicon dioxide particles contain silicon monoxide. (Composition 12) The powder according to configuration 10 or 11, wherein one or more oxide particles include yttrium oxide particles. (Composition 13) The powder according to any one of the items 10 to 12, wherein one or more oxide particles include zirconium oxide particles. (Composition 14) The powder according to configuration 13, wherein the zirconium oxide particles contain Y. (Composition 15) It must contain 50 mol% or more of aluminum oxide. It contains yttrium oxide in an amount of 1.29 mol% or more and 15.02 mol% or less, and It must contain silicon oxide in an amount of 1.90 mol% or more and 7.18 mol% or less. A powder according to any one of items 1 to 13, satisfying at least one of the following conditions. (Composition 16) A powder according to any one of items 1 to 14, containing zirconium oxide in an amount of 3.93 mol% or more and 13.97 mol% or less. (Composition 17) The powder according to configuration 10, wherein the average particle size of oxide particles other than the silicon oxide particles contained in the powder is 10 μm or more and 200 μm or less. (Composition 18) The powder according to configuration 10, wherein the average particle size of oxide particles other than silicon oxide particles contained in the powder is 10 μm or more and 50 μm or less. (Composition 19) The powder according to configuration 1, characterized in that the angle of repose of the powder is 40° or less. (Method 20) A method for manufacturing a ceramic molded object, comprising forming a molded object by heating a material using the powder described in any one of items 1 to 19 with light, characterized in that the heating melts at least one type of oxide particle. (Method 21) A molding process for obtaining an intermediate molded object from a material using powder as described in any one of items 1 to 19, A heating step for heat-treating the aforementioned intermediate molded object, Includes, A method for manufacturing a ceramic molded object, characterized by repairing cracks present in the intermediate molded object by the heating step. (Method 22) The method for producing a ceramic molded product according to method 21, wherein the heating step involves heating at a temperature of 1600°C or higher and 1850°C or lower. (Composition 23) It contains Al, Y, and Si, and the elemental ratio of Y to Si is Y / Si. A ceramic structure characterized by satisfying the conditions 25 / 75 ≤ Y / Si ≤ 95 / 5. (Composition 24) The ceramic structure according to configuration 23, satisfying that Y / Si is 1.0 ≤ Y / Si ≤ 10.0. (Composition 25) Al is greater than Y, and Al is more abundant than Si. A ceramic structure according to configuration 23 or 24, satisfying at least one of the following conditions. (Composition 26) The elemental ratio of Al to Y, Al / Y, is between 4.60 and 73.78, and The elemental ratio of Al to Si (Al / Si) must be between 15.53 and 140.35. A ceramic structure according to any one of the configurations 23 to 25, satisfying at least one of the conditions. (Composition 27) A ceramic structure according to any one of the configurations 23 to 26, further containing Zr. (Composition 28) Al is more abundant than Zr. Y is greater than Zr, and Zr is more abundant than Si. A ceramic structure according to configuration 27, satisfying at least one of the following conditions. (Composition 29) The elemental ratio of Al to Zr (Al / Zr) must be between 9.89 and 44.58. The elemental ratio of Y to Zr, Y / Zr, is between 0.18 and 7.64, and The elemental ratio of Zr to Si, Zr / Si, must be between 0.55 and 7.35. A ceramic structure according to configuration 27 or 28, satisfying at least one of the following conditions. (Composition 30) It must contain 50 mol% or more of aluminum oxide. It must contain yttrium oxide in an amount of 1.29 mol% or more and 15.02 mol% or less. It contains silicon oxide in an amount of 1.90 mol% or more and 7.18 mol% or less, and It must contain zirconium oxide in an amount of 3.93 mol% or more and 13.97 mol% or less. A ceramic structure according to any one of the configurations 23 to 29, satisfying at least one of the conditions. (Composition 31) A ceramic structure according to any one of the configurations 23 to 30, comprising an oxide containing Y and Al. (Composition 32) The ceramic structure according to configuration 31, wherein the oxide containing Y and Al contains at least one of YAlO3 and Y4Al2O9. (Composition 33) A ceramic structure according to any one of configurations 23 to 32, containing an oxide containing Y and Si. (Configuration 34) A ceramic structure according to configuration 31 or 33, comprising an oxide containing Y and Al, and an oxide containing Y and Si, wherein the volume of the oxide containing Y and Al is greater than the volume of the oxide containing Y and Si. (Composition 35) Density is 4.19 [g / cm³] 3 ] The following conditions apply: The three-point bending strength must be 152 [MPa] or higher, and 3-point bending strength [MPa] / Density [g / cm³] 3 ] is 40 [MPa·cm 3 It must be 1 / g or more. A ceramic structure according to any one of the configurations 23 to 34, satisfying at least one of the conditions. (Composition 36) A ceramic structure according to any one of items 23 to 35, An apparatus comprising at least one of electrical components, optical components, metal components, and resin components. [Explanation of Symbols]

[0097] 100 Solidification section 101 Raw material powder 102 Powder bed 103 Unsolidified raw material powder 110 Sculptures 130 base 151 stages 152 Rollers 180 Laser light sources 181 Scanner section 201 Cladding Nozzle 202 Powder supply hole 203 Laser light

Claims

1. A powder for ceramic molding containing one or more types of oxide particles, It contains at least Al, Y, and Si, and the elemental ratio of Y to Si is Y / Si A powder characterized by satisfying the conditions 25 / 75 ≤ Y / Si ≤ 95 / 5.

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

0.

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

0.

4. Al is greater than Y, and Al is more abundant than Si, The powder according to claim 1, satisfying at least one of the following conditions.

5. The elemental ratio of Al to Y, Al / Y, is between 4.60 and 73.78, and The elemental ratio of Al to Si (Al / Si) must be between 21.60 and 87.

45. The powder according to claim 1, satisfying at least one of the following conditions.

6. The powder according to claim 1, further containing Zr.

7. Al is more abundant than Zr, Y is greater than Zr, and The amount of Zr is greater than the amount of Si. The powder according to claim 6, satisfying at least one of the following conditions.

8. The elemental ratio of Al to Zr (Al / Zr) must be between 9.89 and 44.

58. The elemental ratio of Y to Zr, Y / Zr, is between 0.18 and 7.64, and The elemental ratio of Zr to Si, Zr / Si, must be between 0.55 and 7.

35. The powder according to claim 6, satisfying at least one of the following conditions.

9. The powder according to claim 1, which contains silicon monoxide.

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

11. The powder according to claim 10, wherein the silicon dioxide particles contain silicon monoxide.

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

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

14. The powder according to claim 13, wherein the zirconium oxide particles contain Y.

15. It must contain 50 mol% or more of aluminum oxide. It contains yttrium oxide in an amount of 1.29 mol% or more and 15.02 mol% or less, and It contains silicon oxide in an amount of 1.90 mol% or more and 7.18 mol% or less. The powder according to claim 1, satisfying at least one of the following conditions.

16. The powder according to claim 6, containing 3.93 mol% to 13.97 mol% of zirconium oxide.

17. The powder according to claim 10, wherein the average particle size of 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 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, characterized in that the angle of repose of the powder is 40° or less.

20. A method for manufacturing a ceramic molded object, comprising forming a molded object by heating a material using the powder described in any one of claims 1 to 17 with light, characterized in that the heating melts at least one type of oxide particles.

21. A molding process for obtaining an intermediate molded product from a material using powder as described in any one of claims 1 to 17, A heating step for heat-treating the aforementioned intermediate molded object, Includes, A method for manufacturing a ceramic molded object, characterized by repairing cracks present in the intermediate molded object by the heating step.

22. The method for manufacturing a ceramic molded product according to claim 21, wherein the heating step involves heating at a temperature of 1600°C or higher and 1850°C or lower.

23. It contains Al, Y, and Si, and the elemental ratio of Y to Si is Y / Si A ceramic structure characterized by satisfying the conditions 25 / 75 ≤ Y / Si ≤ 95 / 5.

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

0.

25. Al is greater than Y, and Al is more abundant than Si, A ceramic structure according to claim 23, satisfying at least one of the following conditions.

26. The elemental ratio of Al to Y, Al / Y, is between 4.60 and 73.78, and The elemental ratio of Al to Si (Al / Si) must be between 15.53 and 140.

35. A ceramic structure according to claim 23, satisfying at least one of the following conditions.

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

28. Al is more abundant than Zr, Y is greater than Zr, and The amount of Zr is greater than the amount of Si. A ceramic structure according to claim 27, satisfying at least one of the following conditions.

29. The elemental ratio of Al to Zr (Al / Zr) must be between 9.89 and 44.

58. The elemental ratio of Y to Zr, Y / Zr, is between 0.18 and 7.64, and The elemental ratio of Zr to Si, Zr / Si, must be between 0.55 and 7.

35. A ceramic structure according to claim 27, satisfying at least one of the following conditions.

30. It must contain 50 mol% or more of aluminum oxide. It contains yttrium oxide in an amount of 1.29 mol% or more and 15.02 mol% or less. It contains silicon oxide in an amount of 1.90 mol% or more and 7.18 mol% or less, and It contains zirconium oxide in an amount of 3.93 mol% or more and 13.97 mol% or less. A ceramic structure according to claim 23, satisfying at least one of the following conditions.

31. A ceramic structure according to claim 23, comprising an oxide containing Y and Al.

32. The aforementioned oxide containing Y and Al is YAlO ３ and Y ４ Al ２ O ９ The ceramic structure according to claim 31, comprising at least one of the following.

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

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

35. Density is 4.19 [g / cm³] ３ The following conditions apply: The three-point bending strength must be 152 [MPa] or higher, and Three-point bending strength [MPa] / Density [g / cm³] ３ ] is 40 [MPa・cm ３ It must be 1 / g or more. A ceramic structure according to claim 23, satisfying at least one of the following conditions.

36. A ceramic structure according to any one of claims 23 to 30, An apparatus comprising at least one of electrical components, optical components, metal components, and resin components.

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