High sintering activity yttrium aluminum garnet nano-powder, its preparation method and use

Abstract

The application relates to the technical field of yttrium aluminum salt materials, in particular to high-sintering-activity yttrium aluminum garnet nano powder, a preparation method and application thereof, and a chemical formula of the yttrium aluminum garnet is Y 3‑ x RE x Al5O 12 , RE is at least one selected from Ru, Ce, Tb, Nd and Sm, and x is 0-1; the average particle size of the high-sintering-activity yttrium aluminum garnet nano powder is 7-10 nm, the size distribution is 3-40 nm, the high-sintering-activity yttrium aluminum garnet nano powder is an isometric cubic crystal, and the high-sintering-activity yttrium aluminum garnet nano powder is completely dispersed and has no agglomeration. The yttrium aluminum garnet nano powder has high sintering activity, high-density nanocrystal ceramics can be obtained through low-temperature pressureless short-time sintering, the application research of the fine-crystal-dispersed yttrium aluminum garnet nano powder is laid a foundation, and the preparation and application research of the fine-crystal yttrium aluminum garnet nanocrystal ceramic are laid a foundation.

Description

Technical Field

[0001] This invention relates to the field of yttrium aluminum salt materials technology, and in particular to a highly sinterable active yttrium aluminum garnet nanopowder, its preparation method, and its uses. Background Technology

[0002] Yttrium aluminum garnet (YAG) ceramics play a crucial role in laser materials, ceramic materials, optical coatings, and biolabeling. Particularly in the field of solid-state lasers, YAG ceramics, as a matrix material, can provide high-efficiency and high-power laser output. Furthermore, their excellent thermal and chemical stability makes them important for applications in high-temperature structural materials and optical windows. The successful preparation of YAG nanocrystalline ceramics with even better properties further expands their application scope.

[0003] To obtain stable and fine-sized YAG nanocrystalline ceramics, highly sinterable YAG nanopowder is essential. The sintering activity of YAG nanopowder is mainly related to its particle size and dispersibility. Smaller particle sizes result in higher surface energy and thus higher sintering driving force. Simultaneously, smaller particle sizes increase the contact area between particles and shorten atomic diffusion paths, facilitating material transfer and migration during sintering, thereby improving sintering activity. Powders with more uniform particle size distribution can achieve more uniform particle growth and pore removal during sintering, avoiding abnormal grain growth and pore closure caused by excessively rapid local growth, thus improving sintering activity and the density of the final product. Furthermore, highly dispersible YAG nanopowder can achieve better synchronous growth during sintering, resulting in uniform grain size distribution and fewer intergranular pores, further improving sintering activity and the density of the final product. Agglomerated powders are difficult to sinter uniformly, hindering particle growth and pore removal, thus affecting sintering activity; therefore, reducing powder agglomeration improves sintering activity. However, in existing technologies, yttrium aluminum garnet is mostly at the micrometer level, or even if it reaches the nanometer level, it is only a few hundred nanometers. It is also accompanied by severe agglomeration, which limits its sintering activity. In order to obtain YAG ceramics with high density, it is necessary to sinter under high pressure or high temperature for a long time.

[0004] YAG has a cubic crystal system and a complex garnet structure, in which Y 3+ And Al 3+Ions occupy specific lattice positions, forming ordered tetrahedral and octahedral coordination structures. The complexity of this structure presents numerous challenges to the preparation of YAG nanopowders. First, to ensure the integrity of the YAG crystal structure, precise control of the molar ratio of Y to Al and the uniform distribution of dopant elements is required during preparation, demanding extremely high purity and mixing homogeneity of the raw materials. Second, the large lattice energy of YAG easily leads to uneven nucleus growth and grain size distribution during high-temperature solid-state reactions, making it difficult to control particle size and morphology. Furthermore, the high melting point of YAG makes it prone to elemental segregation during melting, affecting the phase purity and optical properties of the final product. In addition, the formation of the garnet structure requires specific heat treatment conditions; improper temperature and time control can lead to lattice defects and stress, affecting the mechanical and optical properties of the material. The preparation of YAG nanopowders involves complex chemical and thermodynamic processes, making it highly challenging and requiring meticulous process control and in-depth fundamental research to overcome.

[0005] Existing YAG nanoparticle preparation technologies mainly include sol-gel method, hydrothermal method, combustion synthesis method, and coprecipitation method. The sol-gel method has attracted much attention due to its ability to precisely control chemical composition and particle size, but it suffers from long preparation cycles and high costs. The hydrothermal method can produce high-purity, uniformly sized YAG nanoparticles; however, it requires sophisticated equipment, and safety issues cannot be ignored. The combustion synthesis method is fast and efficient, but the product has a wide particle size distribution, and precise control is difficult. The coprecipitation method can prepare nanoparticles with uniform particle size and high purity, but this method, including the methods mentioned above, requires heat treatment at high temperatures (≥700℃), which leads to severe hard agglomeration between the resulting powders. This hard agglomeration severely affects the uniformity of particle packing in the green body during the molding stage, resulting in large pores that require sintering at extremely high temperatures (≥1500℃) to remove, which is often accompanied by large-scale grain growth. Therefore, to obtain fine-grained YAG nanocrystalline ceramics by sintering, it is first necessary to improve the existing powder preparation methods to obtain dispersed, fine-grained, equiaxed, and high-purity YAG nanoparticles.

[0006] The preparation of YAG nanoparticles faces several key challenges: First, controlling particle size and morphology during preparation remains difficult, affecting the performance of the final product. Second, the high cost of preparing high-purity YAG nanoparticles hinders large-scale industrial production. Third, the dispersibility and stability of nanoparticles have not been fully resolved, limiting their application in high-performance fields. Finally, the optimization of process parameters and theoretical research for existing preparation methods are insufficient, necessitating further exploration of more efficient and environmentally friendly preparation technologies.

[0007] Therefore, there is an urgent need to provide a YAG nanopowder that is completely dispersed, highly pure, fine-grained (less than 10 nm), has a narrow size distribution, is equiaxed, and has high sintering activity, as well as its preparation method. Summary of the Invention

[0008] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, this invention provides a highly sinterable yttrium aluminum garnet nanopowder, its preparation method, and its applications. The yttrium aluminum garnet nanopowder provided by this invention possesses high sintering activity; high-density nanocrystalline ceramics can be obtained through low-temperature, pressureless, short-time sintering. This lays the foundation for the application research of fine-grained dispersed yttrium aluminum garnet nanopowder and the preparation and application research of fine-grained yttrium aluminum garnet nanocrystalline ceramics.

[0009] Therefore, in a first aspect, the present invention provides a highly sinterable active yttrium aluminum garnet nanoparticle, characterized in that the chemical formula of yttrium aluminum garnet is Ya. 3-x RE x Al5O 12 RE is selected from at least one of Ru, Ce, Tb, Nd, and Sm, and x is 0-1;

[0010] The high-sintering active yttrium aluminum garnet nanoparticles have an average particle size of 7-10 nm and a size distribution of 3-40 nm. They are equiaxed cubic crystals and are completely dispersed without agglomeration.

[0011] This invention provides a yttrium aluminum garnet nanopowder with high sintering activity, which has the characteristics of fine grains (less than 10 nm), narrow size distribution, and equiaxed structure. When used to prepare nanocrystalline ceramics, it can achieve high-density YAG nanocrystalline ceramics by low-temperature pressureless short-time sintering. This lays the foundation for the application research of fine-grained dispersed YAG nanopowder and the preparation and application research of fine-grained YAG nanocrystalline ceramics.

[0012] According to an embodiment of the present invention, the highly sinterable active yttrium aluminum garnet nanopowder is pressurelessly sintered at 1200-1300℃ to obtain yttrium aluminum garnet nanocrystalline ceramics.

[0013] According to an embodiment of the present invention, the sintering time is 0-1h.

[0014] According to an embodiment of the present invention, the density of the yttrium aluminum garnet nanocrystalline ceramic is 99.1%-99.7%.

[0015] According to an embodiment of the present invention, x is 0-0.02.

[0016] According to an embodiment of the present invention, the yttrium aluminum garnet nanoparticles are obtained by the following preparation method:

[0017] The preparation method includes the following steps:

[0018] Prepare a mixed solution containing yttrium salt, aluminum salt, and optional RE salt according to stoichiometric ratio;

[0019] The mixed solution is mixed with a dispersant and then heat-treated to obtain a precursor.

[0020] The precursor is subjected to a first grinding and calcination process to obtain powder.

[0021] The powder is subjected to a second grinding and drying process to obtain the yttrium aluminum garnet nanopowder;

[0022] The RE salt is used to provide the dopant element RE.

[0023] A second aspect of this invention provides a method for preparing highly sinterable active yttrium aluminum garnet nanoparticles, wherein the chemical formula of yttrium aluminum garnet is Ya. 3-x RE x Al5O 12 RE is selected from at least one of Ru, Ce, Tb, Nd, and Sm, and x is 0-1;

[0024] The preparation method includes the following steps:

[0025] Prepare a mixed solution containing yttrium salt, aluminum salt, and optional RE salt according to stoichiometric ratio;

[0026] The mixed solution is mixed with a dispersant and then heat-treated to obtain a precursor.

[0027] The precursor is subjected to a first grinding and calcination process to obtain powder.

[0028] The powder is subjected to a second grinding and drying process to obtain the yttrium aluminum garnet nanopowder;

[0029] The RE salt is used to provide the dopant element RE.

[0030] To address the shortcomings of existing technologies, this invention employs a salt decomposition method combined with two grinding processes. Using yttrium salts, aluminum salts, and optionally RE salts as raw materials, initial powder is obtained through calcination decomposition. This powder is then ground, sieved, and dried to obtain fully dispersed YAG nanoparticles. The YAG nanoparticles prepared by this invention are fully dispersed, free of hard agglomerates, and possess high purity (99.8%-99.9%), fine-grained, equiaxed, and have a narrow size distribution. This preparation method offers advantages such as simplicity and good reproducibility. Furthermore, the prepared YAG nanoparticles can be sintered at low temperature (1200-1300℃) without pressure for a short time to obtain fully dense YAG nanocrystalline ceramics, laying the foundation for research on the application of fine-grained dispersed YAG nanoparticles and the preparation and application of fine-grained YAG nanocrystalline ceramics.

[0031] According to an embodiment of the present invention, the concentration of yttrium salt in the mixed solution is 0.12-0.3 mol / L.

[0032] According to an embodiment of the present invention, the concentration of aluminum salt in the mixed solution is 0.2-0.5 mol / L.

[0033] According to embodiments of the present invention, the dispersant includes at least one selected from polyethylene glycol, ethanol, polyacrylamide, and ethylenediamine.

[0034] According to an embodiment of the present invention, the volume-to-mass ratio of the mixed solution to the dispersant is 200 mL:(2-8) g.

[0035] According to an embodiment of the present invention, the heat treatment is performed at 75-95°C.

[0036] According to an embodiment of the present invention, the first grinding process is performed until the precursor particle size is 300-500 μm.

[0037] According to an embodiment of the present invention, the calcination temperature is 900-1100℃.

[0038] According to an embodiment of the present invention, the calcination treatment time is 2-5 hours.

[0039] According to an embodiment of the present invention, the second grinding process is performed until the powder particle size is 3-40 nm.

[0040] According to embodiments of the present invention, the yttrium salt includes at least one of yttrium nitrate hexahydrate, yttrium acetate, yttrium chloride, and yttrium carbonate.

[0041] According to an embodiment of the present invention, the aluminum salt includes at least one of aluminum nitrate nonahydrate, aluminum sulfate, and aluminum chloride.

[0042] According to an embodiment of the present invention, the RE salt includes at least one of Ru(NO3)3, Ce(NO3)3, Tb(NO3)3, Nd(NO3)3, and Sm(NO3)3.

[0043] According to an embodiment of the present invention, the yttrium aluminum garnet nanoparticles have an average particle size of 7-10 nm and a size distribution of 3-40 nm, and are equiaxed crystals.

[0044] The third aspect of this invention provides the use of the yttrium aluminum garnet nanopowder described in the first aspect or the highly sinterable active yttrium aluminum garnet nanopowder obtained according to the preparation method described in the second aspect for the preparation of yttrium aluminum garnet ceramic materials.

[0045] The beneficial effects of this invention are as follows: The yttrium aluminum garnet nanopowder provided by this invention has advantages such as complete dispersion without hard agglomeration, high purity, fine grains, equiaxed structure, narrow size distribution, simple preparation method, and good reproducibility. Completely dense YAG nanocrystalline ceramics can be obtained by low-temperature, pressureless, short-time sintering. Furthermore, the preparation method of this yttrium aluminum garnet nanopowder is simple, reproducible, and low-cost. In scientific research, it not only provides a foundation for the study of the properties of YAG nanopowder but also for the preparation and performance research of ultrafine-grained YAG nanocrystalline ceramics. This preparation method can be widely used in laser materials, optical coatings, biolabeling, and nanocrystalline ceramic preparation.

[0046] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0047] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0048] Figure 1 The X-ray diffraction pattern of the YAG nanoparticles prepared in Example 1 of the present invention is shown.

[0049] Figure 2 The image shows a transmission electron microscope image of the YAG nanoparticles prepared in Example 1 of the present invention;

[0050] Figure 3 The image shows a scanning electron microscope image of the YAG nanocrystalline ceramics prepared in Example 1 of the present invention;

[0051] Figure 4 The image shows a transmission electron microscope image of the YAG nanoparticles prepared in Example 2 of the present invention;

[0052] Figure 5This shows a high-resolution transmission electron microscope image of the YAG nanoparticles prepared in Example 2 of the present invention;

[0053] Figure 6 The image shows a transmission electron microscope image of the YAG nanoparticles prepared in Example 4 of the present invention.

[0054] Figure 7 The image shows a transmission electron microscope image of the YAG nanoparticles prepared in Example 5 of the present invention;

[0055] Figure 8 The image shows a scanning electron microscope image of the YAG nanocrystalline ceramics prepared in Example 6 of the present invention;

[0056] Figure 9 The image shows a scanning electron microscope image of the YAG nanocrystalline ceramics prepared in Example 7 of the present invention;

[0057] Figure 10 The image shows a scanning electron microscope image of the YAG nanoceramics prepared in Comparative Example 1 of the present invention.

[0058] Figure 11 The image shows a transmission electron microscope image of the YAG nanoparticles prepared in Comparative Example 2 of the present invention.

[0059] Figure 12 The image shows a scanning electron microscope image of the YAG nanocrystalline ceramics prepared in Comparative Example 3 of this invention. Detailed Implementation

[0060] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0061] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0062] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0063] To facilitate understanding of the invention, certain technical and scientific terms are specifically defined below. Unless otherwise expressly defined elsewhere in this document, all other technical and scientific terms used herein have the meaning commonly understood by one of ordinary skill in the art to which this invention pertains.

[0064] In this document, the terms “comprising” or “including” are open-ended expressions, meaning that they include the contents specified in this invention, but do not exclude other aspects.

[0065] In this document, the terms “optionally,” “optionally,” or “optionally” generally refer to an event or condition that may, but may not, occur, and the description includes both cases in which the event or condition occurs and cases in which the event or condition does not occur.

[0066] The sintering activity of YAG nanoparticles is mainly related to the particle size and dispersibility. In existing technologies, yttrium aluminum garnet (YAG) particles are mostly in the micrometer or hundred-nanometer range, and are accompanied by severe agglomeration, limiting their sintering activity. Subsequent high-pressure, long-duration sintering is required to obtain high-density YAG ceramics. Furthermore, existing technologies for preparing YAG nanoparticles often employ gel combustion, which requires complexing agents (such as citric acid) to reduce powder agglomeration. However, in most cases, the prepared YAG powder still exhibits agglomeration, resulting in poor dispersibility and uneven grain size distribution. The addition of complexing agents also complicates the preparation process, requiring precise control of the amount of complexing agent, pH value, and subsequent sintering temperature to ensure the acquisition of ideal YAG powder. In addition, this method requires high sintering temperatures and long sintering times to ensure complete decomposition of organic matter and formation of the YAG phase.

[0067] Based on the above-mentioned prior art, the first aspect of the present invention provides a highly sinterable active yttrium aluminum garnet nanoparticle, characterized in that the chemical formula of yttrium aluminum garnet is Ya. 3-x RE x Al5O 12 RE is selected from at least one of Ru, Ce, Tb, Nd, and Sm, and x is 0-1;

[0068] The high-sintering active yttrium aluminum garnet nanoparticles have an average particle size of 7-10 nm and a size distribution of 3-40 nm. They are equiaxed cubic crystals and are completely dispersed without agglomeration.

[0069] According to a specific embodiment of the present invention, the highly sinterable active yttrium aluminum garnet nanopowder is pressurelessly sintered at 1200-1300℃ to obtain yttrium aluminum garnet nanocrystalline ceramics.

[0070] According to a specific embodiment of the present invention, the sintering time is 0-1h.

[0071] According to a specific embodiment of the present invention, the density of the yttrium aluminum garnet nanocrystalline ceramic is 99.1%-99.7%.

[0072] According to a specific embodiment of the present invention, x is 0-0.02.

[0073] According to a specific embodiment of the present invention, the yttrium aluminum garnet nanoparticles are obtained by the following preparation method:

[0074] The preparation method includes the following steps:

[0075] Prepare a mixed solution containing yttrium salt, aluminum salt, and optional RE salt according to stoichiometric ratio;

[0076] The mixed solution is mixed with a dispersant and then heat-treated to obtain a precursor.

[0077] The precursor is subjected to a first grinding and calcination process to obtain powder.

[0078] The powder is subjected to a second grinding and drying process to obtain the yttrium aluminum garnet nanopowder;

[0079] The RE salt is used to provide the dopant element RE.

[0080] The second aspect of this invention provides a method for preparing highly sinterable yttrium aluminum garnet nanoparticles. This method is based on salt decomposition combined with two grinding processes. It can obtain YAG nanoparticles with no agglomeration, high purity, fine crystals, equiaxed structure, and narrow size distribution without adding complexing agents. It can also achieve low-temperature, pressureless, short-time sintering to obtain fully dense YAG nanocrystalline ceramics.

[0081] Specifically, the chemical formula of the yttrium aluminum garnet is Y. 3-x RE x Al5O 12 RE is selected from at least one of Ru, Ce, Tb, Nd, and Sm, and x is 0-1; the preparation method includes the following steps:

[0082] (1) Prepare a mixed solution containing yttrium salt, aluminum salt and optional RE salt according to stoichiometric ratio;

[0083] The RE salt is used to provide the dopant element RE.

[0084] According to a specific embodiment of the present invention, yttrium salt, aluminum salt, and optionally RE salt can be dissolved in a solvent according to a stoichiometric ratio, and stirred to dissolve them to obtain the mixed solution.

[0085] Specifically, the type of solvent is not particularly limited, and as some specific examples, it includes, but is not limited to, deionized water.

[0086] Specifically, the types of yttrium salts and aluminum salts are not particularly limited, and they are used to provide the corresponding metal ions. As some specific examples, the yttrium salts include, but are not limited to, yttrium nitrate hexahydrate, yttrium acetate, yttrium chloride, yttrium carbonate, etc.; the aluminum salts include, but are not limited to, aluminum nitrate nonahydrate, aluminum sulfate, aluminum chloride, etc.

[0087] Specifically, the concentrations of the yttrium salt and aluminum salt in the mixed solution are not particularly limited. Preferably, the concentration of the yttrium salt is 0.12-0.3 mol / L, such as 0.12 mol / L, 0.14 mol / L, 0.16 mol / L, 0.18 mol / L, 0.2 mol / L, 0.22 mol / L, 0.24 mol / L, 0.26 mol / L, 0.28 mol / L, 0.3 mol / L, etc.; preferably, the concentration of the aluminum salt is 0.2-0.5 mol / L, such as 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, etc. More preferably, the concentration ratio of the yttrium salt and aluminum salt in the mixed solution conforms to the molar ratio of yttrium to aluminum in the yttrium aluminum garnet. Similarly, when the mixed solution contains RE salt, the concentration ratio of the yttrium salt, aluminum salt and RE salt in the mixed solution conforms to the molar ratio of yttrium, aluminum and the corresponding dopant element RE in the yttrium aluminum garnet.

[0088] Specifically, the RE salt can be added as needed to provide dopant elements, thereby improving the optical properties of yttrium aluminum garnet. The dopant elements include, but are not limited to, rare earth elements and / or non-rare earth elements, such as Ce, Tb, Nd, and Sm, and non-rare earth elements such as Ru. The RE salt includes, but is not limited to, Ru(NO3)3, Ce(NO3)3, Tb(NO3)3, Nd(NO3)3, and Sm(NO3)3.

[0089] (2) The mixed solution is mixed with a dispersant and heat-treated to obtain a precursor.

[0090] According to specific embodiments of the present invention, the type of dispersant is not particularly limited, including but not limited to polyethylene glycol, ethanol, polyacrylamide, ethylenediamine, etc.

[0091] Specifically, the molecular weight of the polyethylene glycol is 400-4000.

[0092] According to a specific embodiment of the present invention, the volume-to-mass ratio of the mixed solution to the dispersant is 200 mL:(2-8) g.

[0093] According to a specific embodiment of the present invention, the heat treatment is carried out at 75-95°C, thereby evaporating the water in the solution until it is completely dry, to obtain the precursor.

[0094] Specifically, the heat treatment method is not particularly limited. The solution can be heated to obtain a gel, and the gel can be placed in an oven until completely dried to obtain a precursor.

[0095] (3) The precursor is subjected to a first grinding and calcination treatment to obtain powder.

[0096] According to a specific embodiment of the present invention, the first grinding process is carried out until the precursor particle size is 300-500μm to obtain precursor powder, and the precursor powder is calcined to obtain initial YAG powder.

[0097] Specifically, the temperature and time of the calcination treatment are not particularly limited, and those skilled in the art can choose according to the circumstances. As some specific examples, the temperature of the calcination treatment is 900-1100℃, and the calcination time is 2-5h.

[0098] (4) The powder is subjected to a second grinding and drying process to obtain the yttrium aluminum garnet nanopowder.

[0099] According to a specific embodiment of the present invention, the second grinding process is carried out until the particle size of the powder is 3-40 nm. The grinding method is not particularly limited, but vibratory ball milling is preferred. The ground powder is then sieved and dried to obtain the yttrium aluminum garnet nanoparticles.

[0100] Specifically, the yttrium aluminum garnet (YAG) nanoparticles exhibit high purity, verifiable by X-ray diffraction analysis. The YAG particles are completely dispersed, without hard agglomerates, and are fine in size. Particle size statistics show an average particle size of 7-10 nm and a size distribution of 3-40 nm. The YAG nanoparticles are equiaxed crystals, and high-resolution transmission electron microscopy analysis reveals a cubic phase with no obvious defects. Green bodies formed from this YAG nanoparticle can be sintered at low temperature (1200-1300℃) without pressure for a short time to obtain nearly completely dense YAG nanocrystalline ceramics, indicating that the YAG nanoparticles possess high sintering activity.

[0101] The present invention will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0102] In the following examples and comparative examples, the relevant parameters were obtained through testing using the following methods:

[0103] (1) ICP test: obtained through IRIS Intrepid II, Thermo, China test;

[0104] (2) X-ray diffraction (XRD) test: obtained by D8 Advanced, Bruker, Germany test;

[0105] (3) Transmission electron microscopy (TEM) test and high-resolution transmission electron microscopy (HRTEM) test: obtained by JEM-F200, JEOL, Japan;

[0106] (4) Scanning electron microscopy (SEM) test: obtained by Merlin, Zeiss, Germany test.

[0107] Example 1

[0108] This embodiment provides a method for preparing highly sinterable active YAG nanopowder, the steps of which are as follows:

[0109] 1. Weigh out specific amounts of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate, respectively, and dissolve them in 200 mL of deionized water. Stir continuously until the nitrates are fully dissolved. Confirm the cation concentration by ICP test to obtain Y. 3+ And Al 3+ A mixed solution with ion concentrations of 0.12 mol / L and 0.2 mol / L;

[0110] 2. Add 8g of PEG-4000 as a dispersant to the mixed solution, stir until completely dissolved, and stir the clear mixed solution for 30 minutes;

[0111] 3. Heat the mixed solution to 85°C to evaporate the water, and continue stirring to obtain a transparent, pale yellow gel;

[0112] 4. Place the gel obtained in step 3 in an oven at 70°C to dry it completely, then grind it to a particle size of 320 μm to obtain precursor powder; calcine the precursor at 950°C for 2.5 h to obtain initial YAG powder;

[0113] 5. The initial YAG powder was subjected to vibratory ball milling at a ball-to-powder ratio of 10:1 to obtain powder with a particle size of 8nm;

[0114] 6. The powder after ball milling is sieved and dried to obtain the final product.

[0115] The X-ray diffraction pattern of the obtained product is as follows Figure 1 As shown, comparison with the standard spectrum confirmed it to be a pure YAG phase. This was confirmed by transmission electron microscopy (see [image]). Figure 2 As can be seen, the obtained YAG nanoparticles are completely dispersed, with no hard agglomerates between them. The particles are equiaxed, small in size, with an average particle size of 8 nm and a size distribution of 3-30 nm. High-resolution transmission electron microscopy analysis of the obtained samples confirmed that the particles are cubic phases, and no obvious defects were observed. Using this powder to form green bodies, dense YAG nanocrystalline ceramics with a relative density of 99.6% can be obtained by sintering at 1250℃ without holding. The SEM images are shown below. Figure 3 .

[0116] Example 2

[0117] This embodiment provides a method for preparing highly sinterable active YAG nanopowder, the steps of which are as follows:

[0118] 1. Weigh out specific amounts of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate, respectively, and dissolve them in 200 ml of deionized water. Stir continuously until the nitrates are fully dissolved to obtain Y. 3+ And Al 3+ A mixed solution with ion concentrations of 0.12 mol / L and 0.2 mol / L;

[0119] 2. Add 2g of PEG-4000 as a dispersant to the mixed solution, stir until completely dissolved, and stir the clear mixed solution for 30 minutes;

[0120] 3. Heat the mixed solution to 85°C to evaporate the water, and continue stirring to obtain a transparent, pale yellow gel;

[0121] 4. Place the gel obtained in step 3 in an oven at 70°C to dry it completely, then grind it to a particle size of 450 μm to obtain precursor powder; calcine the precursor at 900°C for 3 h to obtain initial YAG powder;

[0122] 5. The initial YAG powder was subjected to vibratory ball milling at a ball-to-powder ratio of 7.5:1 to obtain powder with a particle size of 8nm;

[0123] 6. The powder after ball milling is sieved and dried to obtain the final product.

[0124] The X-ray diffraction pattern of the obtained product was compared with the standard spectrum, confirming that it was a pure YAG phase. The microstructure of the obtained product is as follows. Figure 4 As shown, the obtained YAG nanoparticles are completely dispersed, with no hard agglomeration between particles. The particles are equiaxed, small in size, with an average particle size of 8 nm and a size distribution of 3-36 nm. High-resolution transmission electron microscopy images of the obtained samples are shown below. Figure 5As shown, the obtained particles are cubic phases, and no obvious defects were observed. The green body formed from this powder can be sintered at 1250℃ without heat treatment to obtain dense YAG nanocrystalline ceramics with a relative density of 99.6%.

[0125] Example 3

[0126] This embodiment provides a method for preparing highly sinterable active YAG nanopowder, the steps of which are as follows:

[0127] 1. Weigh out specific amounts of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate, respectively, and dissolve them in 200 ml of deionized water. Stir continuously until the nitrates are fully dissolved to obtain Y. 3+ And Al 3+ A mixed solution with ion concentrations of 0.12 mol / L and 0.2 mol / L;

[0128] 2. Add 4g of PEG-4000 as a dispersant to the mixed solution, stir until completely dissolved, and stir the clear mixed solution for 30 minutes;

[0129] 3. Heat the mixed solution to 85°C to evaporate the water, and continue stirring to obtain a transparent, pale yellow gel;

[0130] 4. Place the gel obtained in step 3 in an oven at 70°C to dry it completely, then grind it to a particle size of 450 μm to obtain precursor powder; calcine the precursor at 900°C for 3 h to obtain initial YAG powder;

[0131] 5. The initial YAG powder was subjected to vibratory ball milling at a ball-to-powder ratio of 10:1 to obtain powder with a particle size of 9nm;

[0132] 6. The powder after ball milling is sieved and dried to obtain the final product.

[0133] The obtained YAG nanoparticles are completely dispersed, with no hard agglomerates between them. The particles are equiaxed and small in size, with an average particle size of 9 nm and a size distribution of 3-38 nm. The green body formed from this powder is sintered at 1200℃ for 1 h to obtain dense YAG nanocrystalline ceramics with a relative density of 99.7%.

[0134] Example 4

[0135] This embodiment provides a method for preparing highly sinterable active YAG nanopowder, the steps of which are as follows:

[0136] 1. Weigh out specific amounts of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate, respectively, and dissolve them in 200 ml of deionized water. Stir continuously until the nitrates are fully dissolved to obtain Y. 3+ And Al 3+Mixed solutions with ion concentrations of 0.12 mol / L and 0.2 mol / L were prepared; a measured amount of Ru(NO3)3 was weighed out as the Ru source to achieve doping.

[0137] 2. Add 4g of PEG-4000 as a dispersant to the mixed solution, stir until completely dissolved, and stir the clear mixed solution for 30 minutes;

[0138] 3. Heat the mixed solution to 85°C to evaporate the water, and continue stirring to obtain a transparent, pale yellow gel;

[0139] 4. Place the gel obtained in step 3 in an oven at 70°C to dry it completely, then grind it to a particle size of 480 μm to obtain precursor powder; calcine the precursor at 900°C for 3 h to obtain initial YAG powder;

[0140] 5. The initial YAG powder was subjected to vibratory ball milling at a ball-to-powder ratio of 7.5:1 to obtain powder with a particle size of 7nm;

[0141] 6. The powder after ball milling is sieved and dried to obtain the final product.

[0142] The microstructure of the obtained product is as follows Figure 6 As shown, the obtained YAG nanoparticles are completely dispersed, with no hard agglomerates between particles. The particles are equiaxed, small in size, with an average particle size of 7 nm and a size distribution of 3-35 nm. The Ru content in the obtained powder is 0.05 wt%. Using this powder to form a green body, sintering it at 1250℃ for 30 min yields dense YAG nanocrystalline ceramics with a relative density of 99.7%.

[0143] Example 5

[0144] This embodiment provides a method for preparing highly sinterable active YAG nanopowder, the steps of which are as follows:

[0145] 1. Weigh out specific amounts of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate, respectively, and dissolve them in 200 ml of deionized water. Stir continuously until the nitrates are fully dissolved to obtain Y. 3+ And Al 3+ Mixed solutions with ion concentrations of 0.18 mol / L and 0.3 mol / L were prepared; a measured amount of Ce(NO3)3 was weighed out as the Ce source to achieve doping.

[0146] 2. Add 8g of PEG-4000 as a dispersant to the mixed solution, stir until completely dissolved, and stir the clear mixed solution for 30 minutes;

[0147] 3. Heat the mixed solution to 85°C to evaporate the water, and continue stirring to obtain a transparent, pale yellow gel;

[0148] 4. Place the gel obtained in step 3 in an oven at 70°C to dry it completely, then grind it to a particle size of 400 μm to obtain precursor powder; calcine the precursor at 900°C for 3 h to obtain initial YAG powder;

[0149] 5. The initial YAG powder was subjected to vibratory ball milling at a ball-to-powder ratio of 7.5:1 to obtain powder with a particle size of 8nm;

[0150] 6. The powder after ball milling is sieved and dried to obtain the final product.

[0151] The microstructure of the obtained product is as follows Figure 7 As shown, the obtained YAG nanoparticles are completely dispersed, with no hard agglomerates between particles. The particles are equiaxed, small in size, with an average particle size of 8 nm and a size distribution of 3-38 nm. The Ce content in the obtained powder is 0.01 wt%. Using this powder to form a green body, sintering it at 1200℃ for 1 h yields dense YAG nanocrystalline ceramics with a relative density of 99.7%.

[0152] Example 6

[0153] This embodiment provides a method for preparing highly sinterable active YAG nanopowder, the steps of which are as follows:

[0154] 1. Weigh out specific amounts of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate, respectively, and dissolve them in 200 ml of deionized water. Stir continuously until the nitrates are fully dissolved to obtain Y. 3+ And Al 3+ A mixed solution with ion concentrations of 0.3 mol / L and 0.5 mol / L;

[0155] 2. Add 8g of PEG-4000 as a dispersant to the mixed solution, stir until completely dissolved, and stir the clear mixed solution for 30 minutes;

[0156] 3. Heat the mixed solution to 85°C to evaporate the water, and continue stirring to obtain a transparent, pale yellow gel;

[0157] 4. Place the gel obtained in step 3 in an oven at 70°C to dry it completely, then grind it to a particle size of 450 μm to obtain precursor powder; calcine the precursor at 950°C for 3 h to obtain initial YAG powder;

[0158] 5. The initial YAG powder was subjected to vibratory ball milling at a ball-to-powder ratio of 7.5:1 to obtain powder with a particle size of 9nm;

[0159] 6. The powder after ball milling is sieved and dried to obtain the final product.

[0160] The obtained YAG nanoparticles were completely dispersed, with no hard agglomerations between them. The particles were equiaxed, small in size, with an average particle size of 9 nm and a size distribution of 3-37 nm. Using this powder to form a green body, dense YAG nanocrystalline ceramics with a relative density of 99.6% could be obtained by sintering at 1250℃ without holding. Scanning electron microscope images of the obtained dense YAG nanocrystalline ceramics are shown below. Figure 8 As shown.

[0161] Example 7

[0162] This embodiment provides a method for preparing highly sinterable active YAG nanopowder, the steps of which are as follows:

[0163] 1. Commercially available yttrium oxide powder with a quantitative purity of 99.9% was dissolved in concentrated nitric acid aqueous solution at room temperature to obtain an aqueous solution of yttrium nitrate of a specific concentration. Alternatively, commercially available alumina powder with a quantitative purity of 99.9% was weighed, added to concentrated nitric acid, and stirred continuously at 90°C until completely dissolved to obtain an aqueous solution of aluminum nitrate of a specific concentration.

[0164] 2. Mix the obtained nitrate aqueous solution in a specific ratio, and stir continuously to ensure uniform mixing of the nitrates, to obtain Y. 3+ And Al 3+ A mixed solution with ion concentrations of 0.3 mol / L and 0.5 mol / L;

[0165] 3. Add 4g of PEG-4000 as a dispersant to the mixed solution, stir until completely dissolved, and stir the clear mixed solution for 30 minutes;

[0166] 3. Heat the mixed solution to 85°C to evaporate the water, and continue stirring to obtain a transparent, pale yellow gel;

[0167] 4. Place the gel obtained in step 3 in an oven at 70°C to dry it completely, then grind it to a particle size of 490 μm to obtain precursor powder; calcine the precursor at 900°C for 3 h to obtain initial YAG powder;

[0168] 5. The initial YAG powder was subjected to vibratory ball milling at a ball-to-powder ratio of 7.5:1 to obtain powder with a particle size of 9nm;

[0169] 6. The powder after ball milling is sieved and dried to obtain the final product.

[0170] The obtained product is a pure YAG phase. The obtained YAG nanoparticles are completely dispersed, with no hard agglomerations between particles. The particles are equiaxed, small in size, with an average particle size of 9 nm and a size distribution of 3-30 nm. The green body obtained from this powder is sintered at 1200℃ for 1 h to obtain dense YAG nanocrystalline ceramics with a relative density of 99.5%. Scanning electron microscopy images of the sintered dense YAG nanocrystalline ceramics are shown below. Figure 9 As shown.

[0171] Comparative Example 1

[0172] This comparative example provides a method for preparing YAG powder, the steps of which are as follows:

[0173] 1. Weigh out specific amounts of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate, respectively, and dissolve them in 200 mL of deionized water. Stir continuously until the nitrates are fully dissolved. Confirm the cation concentration by ICP test to obtain Y. 3+ And Al 3+ A mixed solution with ion concentrations of 0.12 mol / L and 0.2 mol / L;

[0174] 2. Add 8g of PEG-4000 as a dispersant to the mixed solution, stir until completely dissolved, and stir the clear mixed solution for 30 minutes;

[0175] 3. Heat the mixed solution to 85°C to evaporate the water, and continue stirring to obtain a gel;

[0176] 4. Place the gel obtained in step 3 in an oven at 70°C to dry it completely, and then take it out to obtain the precursor; calcine the precursor at 950°C for 2.5 h to obtain the initial YAG powder;

[0177] 5. The initial YAG powder was subjected to vibratory ball milling at a ball-to-powder ratio of 10:1 to obtain powder with a particle size of 10nm;

[0178] 6. The powder after ball milling is sieved and dried to obtain the final product.

[0179] The obtained YAG powder is black, with an average grain size of 10 nm and a size distribution of 3-40 nm, and the particles are dispersed. The green body obtained from its molding process produces a large number of intragranular pores during sintering, and its microstructure is as follows... Figure 10 As shown.

[0180] Comparative Example 2

[0181] This comparative example provides a method for preparing YAG powder, the steps of which are as follows:

[0182] 1. Weigh out specific amounts of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate, respectively, and dissolve them in 200 mL of deionized water. Stir continuously until the nitrates are fully dissolved. Confirm the cation concentration by ICP test to obtain Y. 3+ And Al 3+ A mixed solution with ion concentrations of 0.12 mol / L and 0.2 mol / L;

[0183] 2. Add 8g of PEG-4000 as a dispersant to the mixed solution, stir until completely dissolved, and stir the clear mixed solution for 30 minutes;

[0184] 3. Heat the mixed solution to 85°C to evaporate the water, and continue stirring to obtain a transparent, pale yellow gel;

[0185] 4. Place the gel obtained in step 3 in an oven at 70°C to dry it completely, and then take it out to obtain the precursor; calcine the precursor at 950°C for 2.5 h to obtain YAG.

[0186] The YAG powder particles showed severe agglomeration, with a particle size of 200-300 nm. TEM images are shown below. Figure 11 The large pores present in the green body obtained by its molding cannot be eliminated during the pressureless sintering process.

[0187] Comparative Example 3

[0188] This comparative example provides a method for preparing YAG powder, the steps of which are as follows:

[0189] 1. Weigh out specific amounts of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate, respectively, and dissolve them in 200 mL of deionized water. Stir continuously until the nitrates are fully dissolved. Confirm the cation concentration by ICP test to obtain Y. 3+ And Al 3+ A mixed solution with ion concentrations of 0.12 mol / L and 0.2 mol / L;

[0190] 2. Add PEG-6000 and citric acid monohydrate (molar ratio of 1:2) to the mixed solution to obtain a mixed solution containing 8wt% PEG-6000. Heat continuously in a 90°C water bath with constant stirring to obtain a gel.

[0191] 3. After aging the gel obtained in step 2, transfer it to an oven to dry. After 12 hours, transfer it to a muffle furnace for hot annealing at 1000℃ for 2.5 hours to induce a self-propagating combustion reaction. Then grind the gel to obtain YAG.

[0192] The average grain size of the obtained YAG powder was 318 nm, with particle lengths of 250-650 nm and widths of 50-100 nm, and severe agglomeration between particles. The large pores present in the green body obtained by shaping could not be eliminated during pressureless sintering. Its microstructure is as follows: Figure 12 As shown.

[0193] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0194] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing highly sintered active yttrium aluminum garnet nanopowder, characterized in that, The chemical formula of yttrium aluminum garnet is Y. 3-x RE x Al5O 12 , RE Selected from at least one of Ru, Ce, Tb, Nd, and Sm, where x is 0-1; The preparation method includes the following steps: Prepare a solution containing yttrium salts, aluminum salts, and optional other salts according to stoichiometric ratios. RE A mixed solution of salts; The mixed solution is mixed with a dispersant and then heat-treated to obtain a precursor. The precursor is subjected to a first grinding and calcination process to obtain powder. The powder is subjected to a second grinding and drying process to obtain the yttrium aluminum garnet nanopowder; Among them, the RE Salt is used to provide dopant elements. RE ; The dispersant is polyethylene glycol, and the molecular weight of the polyethylene glycol is 400-4000; The volume-to-mass ratio of the mixed solution to the dispersant is 200 mL:(2-8) g; The first grinding process is carried out until the precursor particle size is 300-500 μm; The second grinding process is performed until the powder particle size is 3-40 nm; The high-sintering active yttrium aluminum garnet nanopowder has an average particle size of 7-10 nm and a size distribution of 3-40 nm. It is an isometric cubic crystal and is completely dispersed without agglomeration. The concentration of yttrium salt in the mixed solution is 0.12-0.3 mol / L; The concentration of aluminum salt in the mixed solution is 0.2-0.5 mol / L; The heat treatment is carried out at 75-95℃; The calcination temperature is 900-1100℃; The calcination treatment time is 2-5 hours.

2. The preparation method according to claim 1, characterized in that, The highly sinterable active yttrium aluminum garnet nanopowder was pressurelessly sintered at 1200-1300 ℃ to obtain yttrium aluminum garnet nanocrystalline ceramics.

3. The preparation method according to claim 2, characterized in that, The sintering time is 0-1 h.

4. The preparation method according to claim 2, characterized in that, The density of the yttrium aluminum garnet nanocrystalline ceramic is 99.1%-99.7%.

5. The preparation method according to claim 1, characterized in that, x is between 0 and 0.

02.

6. The preparation method according to claim 1, characterized in that, The yttrium salt includes at least one of yttrium nitrate, yttrium acetate, yttrium chloride, and yttrium carbonate.

7. The preparation method according to claim 1, characterized in that, The aluminum salt includes at least one of aluminum nitrate, aluminum sulfate, and aluminum chloride.

8. The preparation method according to claim 1, characterized in that, The RE The salt includes at least one of Ru(NO3)3, Ce(NO3)3, Tb(NO3)3, Nd(NO3)3, and Sm(NO3)3.

9. The use of the highly sintered active yttrium aluminum garnet nanoparticles obtained by the preparation method according to any one of claims 1-8 for the preparation of yttrium aluminum garnet ceramic materials.

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