Yttrium aluminum garnet nano-powder with high sintering activity as well as preparation method and application of yttrium aluminum garnet nano-powder

Abstract

The invention relates to the technical field of yttrium aluminum salt materials, in particular to yttrium aluminum garnet nano powder with high sintering activity and a preparation method and application thereof, the chemical formula of yttrium aluminum garnet is Y (3-x) RExAl5O12, RE is selected from at least one of 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 equiaxed cubic crystal, and the high-sintering-activity yttrium aluminum garnet nano-powder is completely dispersed and free of agglomeration. The yttrium aluminum garnet nano-powder has high sintering activity, high-density nanocrystalline ceramic can be obtained through low-temperature non-pressure short-time sintering, and a foundation is laid for application research of fine-grain dispersed yttrium aluminum garnet nano-powder and preparation and application research of fine-grain yttrium aluminum garnet nanocrystalline ceramic.

Description

Technical Field

[0001] The invention relates to the technical field of yttrium aluminum salt materials, and in particular to a high sintering activity yttrium aluminum garnet nano powder and a preparation method and application thereof. Background Art

[0002] Yttrium aluminum garnet (YAG) ceramic materials play an important role in the fields of laser materials, ceramic materials, optical coatings, and biomarkers. Especially in the field of solid-state lasers, YAG ceramics, as a matrix material, can provide high-efficiency and high-power laser output. In addition, its good thermal and chemical stability also makes it important in high-temperature structural materials and optical windows. The successful preparation of YAG nanocrystalline ceramics with more excellent performance has further expanded the scope of application.

[0003] To obtain YAG nanocrystalline ceramics with stable performance and fine size, YAG nanopowders with high sintering activity are first required. The sintering activity of YAG nanopowders is mainly related to the particle size and dispersibility of the powder. The smaller the particle size of the YAG nanopowder, the higher the surface energy, and thus has a higher sintering driving force. At the same time, the smaller particle size increases the contact area between particles and shortens the atomic diffusion path, which is conducive to the transfer and migration of substances during the sintering process, thereby improving the sintering activity. Powders with relatively uniform particle size distribution can more evenly grow particles and eliminate pores during the sintering process, avoiding abnormal grain growth and pore closure caused by local excessive growth, thereby improving the sintering activity and the density of the final product. In addition, highly dispersible YAG nanopowders can better grow synchronously during sintering, making the grain size distribution uniform and the pore content between the grains less, thereby improving the sintering activity and the density of the final product; agglomerated powders are difficult to achieve uniform particle growth and pore elimination during the sintering process, which will affect the sintering activity, so reducing powder agglomeration can improve the sintering activity. However, in the prior art, yttrium aluminum garnet is mostly at the micron level, or even at the nano level, it is only a few hundred nanometers, and is accompanied by serious agglomeration, etc., which limits its sintering activity. Subsequently, it needs to be sintered for a long time under high pressure or high temperature conditions to obtain YAG ceramics with higher density.

[0004] The crystal structure of YAG is cubic and has a complex garnet structure. 3+ and Al 3+The ions occupy specific lattice positions to form ordered tetrahedral and octahedral coordination structures. The complexity of this structure makes the preparation process of YAG nanopowders face many difficulties. First, in order to ensure the integrity of the crystal structure of YAG, it is necessary to accurately control the molar ratio of Y and Al and the uniform distribution of doping elements during the preparation process, which requires extremely high purity and mixing uniformity of the raw materials. Secondly, the lattice energy of YAG is large, and it is easy to form uneven nucleus growth and grain size distribution during high-temperature solid-phase reaction, which makes it difficult to control particle size and morphology. Furthermore, YAG has a high melting point, and element segregation is prone to occur during the melting process, affecting the phase purity and optical properties of the final product. In addition, the formation of garnet structure requires specific heat treatment conditions. Improper temperature and time control will lead to lattice defects and stress, affecting the mechanical and optical properties of the material. The preparation process of YAG nanopowder involves complex chemical and thermodynamic processes, which are difficult and require fine process control and in-depth basic research to overcome.

[0005] Existing YAG nanoparticle preparation technologies mainly include sol-gel method, hydrothermal method, combustion synthesis method, coprecipitation method, etc. The sol-gel method has attracted much attention because it can accurately control the chemical composition and particle size, but there are problems such as long preparation cycle and high cost. The hydrothermal method can produce YAG nanoparticles with high purity and uniform particle size, but it has high requirements for equipment and safety issues cannot be ignored. The combustion synthesis method is fast and efficient, but the product particle size distribution is wide and it is difficult to achieve precise control. The coprecipitation method can prepare nanopowders with uniform particle size and high purity, but this method, including the above methods, requires heat treatment at a high temperature (≥700°C), which will cause serious hard agglomeration between the obtained powders. The hard agglomeration between the powders will seriously affect the uniformity of the particle stacking of the green body during the molding stage, so that there are large pores in it that require extremely high temperature (≥1500°C) sintering to remove, but this is often accompanied by large-scale grain growth. Therefore, in order to sinter fine-grained YAG nanocrystalline ceramics, it is first necessary to improve the existing powder preparation method to obtain dispersed, fine-grained, equiaxed, and high-purity YAG nanoparticles.

[0006] The preparation of YAG nanoparticles mainly faces the following problems: First, it is still difficult to control the particle size and morphology during the preparation process, which affects the performance of the final product; second, the preparation cost of high-purity YAG nanoparticles is high, making it difficult to achieve large-scale industrial production; third, the dispersibility and stability of nanoparticles have not been completely solved, limiting their application in high-performance fields. Finally, the process parameter optimization and theoretical research of the existing preparation methods are still insufficient, and further exploration of more efficient and environmentally friendly preparation technologies is needed.

[0007] Therefore, there is an urgent need to provide a YAG nanopowder with complete dispersion, high purity, fine crystals (less than 10 nm), narrow size distribution, equiaxed, high sintering activity and a preparation method thereof. Summary of the invention

[0008] The present invention aims to solve one of the technical problems in the related art to at least a certain extent. To this end, the present invention provides a yttrium aluminum garnet nanopowder with high sintering activity and a preparation method and application thereof. The yttrium aluminum garnet nanopowder provided by the present invention has high sintering activity, and can obtain high-density nanocrystalline ceramics by sintering at low temperature without pressure for a short time, which lays a 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] To this end, the first aspect of the present invention provides a high sintering activity yttrium aluminum garnet nano powder, characterized in that the chemical formula of 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;

[0010] The high sintering activity yttrium aluminum garnet nano powder has an average particle size of 7-10 nm and a size distribution of 3-40 nm. It is an equiaxed cubic crystal. The high sintering activity yttrium aluminum garnet nano powder is completely dispersed and has no agglomeration.

[0011] The present invention provides a yttrium aluminum garnet nano powder with high sintering activity, which has the characteristics of fine crystal (less than 10nm), narrow size distribution, equiaxed and the like. It can be used to prepare nanocrystalline ceramics to achieve low-temperature pressureless short-time sintering to obtain high-density YAG nanocrystalline ceramics, laying a foundation for the application research of fine-crystalline dispersed YAG nano powder and the preparation and application research of fine-crystalline YAG nanocrystalline ceramics.

[0012] According to an embodiment of the present invention, the high sintering activity yttrium aluminum garnet nanopowder is pressurelessly sintered at 1200-1300° C. 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 nanopowder is obtained by the following preparation method:

[0017] The preparation method comprises the following steps:

[0018] A mixed solution containing yttrium salt, aluminum salt and optional RE salt is prepared in a stoichiometric ratio;

[0019] The mixed solution is mixed with a dispersant, and a precursor is obtained by heat treatment;

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

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

[0022] Wherein, the RE salt is used to provide the doping element RE.

[0023] The second aspect of the present invention provides a method for preparing a yttrium aluminum garnet nanopowder with high sintering activity, wherein 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;

[0024] The preparation method comprises the following steps:

[0025] A mixed solution containing yttrium salt, aluminum salt and optional RE salt is prepared in a stoichiometric ratio;

[0026] The mixed solution is mixed with a dispersant, and a precursor is obtained by heat treatment;

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

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

[0029] Wherein, the RE salt is used to provide the doping element RE.

[0030] In order to solve the deficiencies in the prior art, the present invention uses a salt decomposition method combined with two grinding processes, uses yttrium salt, aluminum salt and optional RE salt as raw materials, obtains initial powder by calcination and decomposition, and then obtains completely dispersed YAG nanoparticles through grinding, screening and drying. The YAG nanoparticles prepared by the present invention are completely dispersed, free of hard agglomerates, high in purity (up to 99.8%-99.9%), fine-grained, equiaxed, and narrow in size distribution. The preparation method has the advantages of simplicity and good repeatability. In addition, the prepared YAG nanoparticles can be sintered at low temperature (1200-1300°C) without pressure for a short time to obtain completely dense YAG nanocrystalline ceramics, which lays a foundation for the application research of fine-grained dispersed YAG nanopowders and the preparation and application research 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 the aluminum salt in the mixed solution is 0.2-0.5 mol / L.

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

[0034] According to an embodiment of the present invention, the volume 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 temperature of the calcination treatment is 900-1100°C.

[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 an embodiment 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 nanopowder has an average particle size of 7-10 nm, a size distribution of 3-40 nm, and is an equiaxed crystal.

[0044] The third aspect of the present invention provides use of the yttrium aluminum garnet nanopowder described in the first aspect or the high sintering activity yttrium aluminum garnet nanopowder obtained according to the preparation method described in the second aspect for preparing yttrium aluminum garnet ceramic material.

[0045] The beneficial effects of the present invention are as follows: the yttrium aluminum garnet nano powder provided by the present invention has the advantages of complete dispersion without hard agglomeration, high purity, fine crystal, equiaxed, narrow size distribution, simple preparation method, good repeatability, etc., and can obtain completely dense YAG nanocrystalline ceramics by short-time sintering without pressure at low temperature. At the same time, the preparation method of the yttrium aluminum garnet nano powder is simple in process, good in repeatability, and low in cost. In scientific research, it not only provides a basis for the characteristic research of YAG nano powder, but also provides a basis for the preparation and performance research of ultrafine crystal YAG nanocrystalline ceramics. The preparation method can be widely used in the fields of laser materials, optical coatings, biological markers, and nanocrystalline ceramic preparation.

[0046] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0050] Figure 3 The scanning electron microscope image of the YAG nanocrystalline ceramic prepared in Example 1 of the present invention is shown;

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

[0052] Figure 5A high-resolution transmission electron microscopy image of YAG nanoparticles prepared in Example 2 of the present invention is shown;

[0053] Figure 6 The transmission electron microscope image of the YAG nanoparticles prepared in Example 4 of the present invention is shown;

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

[0055] Figure 8 The scanning electron microscope image of the YAG nanocrystalline ceramic prepared in Example 6 of the present invention is shown;

[0056] Fig. 9 The scanning electron microscope image of the YAG nanocrystalline ceramic prepared in Example 7 of the present invention is shown;

[0057] Fig.10 The scanning electron microscope image of the YAG nanoceramic prepared in Comparative Example 1 of the present invention is shown;

[0058] Fig.11 The transmission electron microscope image of the YAG nanoparticles prepared in Comparative Example 2 of the present invention is shown;

[0059] Fig.12 The scanning electron microscope image of the YAG nanocrystalline ceramic prepared in Comparative Example 3 of the present invention is shown. DETAILED DESCRIPTION

[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 understood 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 understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. Further, in the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0062] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0063] In order to make the present invention more easily understood, certain technical and scientific terms are specifically defined below. Unless otherwise clearly defined elsewhere in this document, all other technical and scientific terms used herein have the meanings commonly understood by those skilled in the art to which the present invention belongs.

[0064] In this document, the terms “include” or “comprising” are open expressions, that is, including the contents specified in the present invention but not excluding other contents.

[0065] As used herein, the terms "optionally", "optional" or "optionally" generally mean that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0066] The sintering activity of YAG nano powder is mainly related to the particle size and powder dispersibility of the powder. In the prior art, the particle size of yttrium aluminum garnet is mostly micrometer level or hundred nanometer level, accompanied by serious agglomeration phenomenon, etc., which limits its sintering activity. It is necessary to sinter under high pressure for a long time to obtain high-density YAG ceramics. At the same time, the gel combustion method is often used in the prior art to prepare YAG nano particles. Its raw materials need to use complexing agents (such as citric acid) to reduce powder agglomeration, but in most cases, the prepared YAG powder will still have agglomeration phenomenon, resulting in poor powder dispersibility and uneven grain size distribution. At the same time, the addition of complexing agents will also make the preparation process complicated, and it is necessary to accurately control the dosage of complexing agents, pH value and subsequent sintering temperature and other conditions to ensure that the ideal YAG powder is obtained. In addition, the sintering temperature required for this method is also high, and the sintering time is long to ensure the complete decomposition of organic matter and the formation of YAG phase.

[0067] Based on the above prior art, the first aspect of the present invention provides a high sintering activity yttrium aluminum garnet nano powder, characterized in that the chemical formula of 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;

[0068] The high sintering activity yttrium aluminum garnet nano powder has an average particle size of 7-10 nm and a size distribution of 3-40 nm. It is an equiaxed cubic crystal. The high sintering activity yttrium aluminum garnet nano powder is completely dispersed and has no agglomeration.

[0069] According to a specific embodiment of the present invention, the high sintering activity yttrium aluminum garnet nanopowder is pressurelessly sintered at 1200-1300° C. 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 nanopowder is obtained by the following preparation method:

[0074] The preparation method comprises the following steps:

[0075] A mixed solution containing yttrium salt, aluminum salt and optional RE salt is prepared in a stoichiometric ratio;

[0076] The mixed solution is mixed with a dispersant, and a precursor is obtained by heat treatment;

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

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

[0079] Wherein, the RE salt is used to provide the doping element RE.

[0080] The second aspect of the present invention provides a method for preparing yttrium aluminum garnet nanopowder with high sintering activity. The method is based on a salt decomposition method combined with two grinding processes. Without adding a complexing agent, YAG nanoparticles with no agglomeration, high purity, fine grains, equiaxed grains, and narrow size distribution can be obtained, and low-temperature, pressureless, short-time sintering can be achieved 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 comprises the following steps:

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

[0083] Wherein, the RE salt is used to provide the doping element RE.

[0084] According to a specific embodiment of the present invention, yttrium salt, aluminum salt and optional 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 the solvent is not particularly limited, and some specific examples include but are not limited to deionized water.

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

[0087] Specifically, the concentrations of the yttrium salt and the 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 the aluminum salt in the mixed solution conforms to the molar ratio of yttrium element to aluminum element 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 element, aluminum element and corresponding doping element RE in the yttrium aluminum garnet.

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

[0089] (2) The mixed solution is mixed with a dispersant and a precursor is obtained by heat treatment.

[0090] According to a specific embodiment of the present invention, the type of the dispersant is not particularly limited, and includes but is not limited to polyethylene glycol, ethanol, polyacrylamide, ethylenediamine, and the like.

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

[0092] According to a specific embodiment of the present invention, the volume 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 to complete dryness to obtain a precursor.

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

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

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

[0097] Specifically, the temperature and time of the calcination treatment are not particularly limited, and those skilled in the art may select them according to the circumstances. As some specific examples, the temperature of the calcination treatment is 900-1100° C., and the calcination time is 2-5 hours.

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

[0099] According to a specific embodiment of the present invention, the second grinding process is performed until the particle size of the powder is 3-40 nm. The grinding process is not particularly limited, and preferably a vibration ball milling process is used. The ground powder is sieved and dried to obtain the yttrium aluminum garnet nanopowder.

[0100] Specifically, the yttrium aluminum garnet nanopowder has a high purity, which can be verified by X-ray diffraction spectrum analysis. The yttrium aluminum garnet particles are completely dispersed, there is no hard agglomeration between the particles, and the size is small. The particle size statistics prove that the average particle size of the yttrium aluminum garnet nanopowder is 7-10nm, and the size distribution is 3-40nm. The yttrium aluminum garnet nanopowder is an equiaxed crystal. Through high-resolution transmission electron microscopy analysis, it can be seen that the particles are cubic phases and have no obvious defects. Based on the green body obtained by molding the yttrium aluminum garnet, a nearly fully dense YAG nanocrystalline ceramic can be obtained by short-time sintering without pressure at low temperature (1200-1300°C), indicating that the yttrium aluminum garnet nanopowder has high sintering activity.

[0101] The scheme of the present invention will be explained below in conjunction with the embodiments. It will be appreciated by those skilled in the art that the following embodiments are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Where specific techniques or conditions are not indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used are not indicated by the manufacturer and are all conventional products that can be obtained commercially.

[0102] In the following examples and comparative examples, the relevant parameters were tested by the following methods:

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

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

[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 microscope (SEM) test: obtained by Merlin, Zeiss, Germany.

[0107] Example 1

[0108] This embodiment provides a method for preparing YAG nanopowder with high sintering activity, and the steps are as follows:

[0109] 1. Weigh a certain amount of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate respectively and dissolve them in 200 mL of deionized water. Stir continuously to fully dissolve the nitrate. Confirm the cation concentration by ICP test to obtain Y 3+ and Al 3+ Mixed solutions with ion concentrations of 0.12 mol / L and 0.2 mol / L;

[0110] 2. Add 8 g PEG-4000 as a dispersant to the mixed solution, stir to completely dissolve it, and stir the clarified mixed solution for 30 min;

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

[0112] 4. The gel obtained in step 3 was placed in an oven at 70°C to completely dry, then taken out and ground to a particle size of 320 μm to obtain a precursor powder; the precursor was calcined at 950°C for 2.5 h to obtain an initial YAG powder;

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

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

[0115] The X-ray diffraction spectrum of the obtained product is as follows Figure 1 As shown, after comparison with the standard spectrum, it is confirmed to be pure YAG phase. Figure 2 ) It can be seen that the obtained YAG nanoparticles are completely dispersed, there are no hard agglomerates between the particles, the particle shape is equiaxed, the size is small, the statistical average particle size is 8nm, and the size distribution is 3-30nm. High-resolution transmission electron microscopy analysis of the obtained samples proves that the obtained particles are cubic phases, and no obvious defects are observed in them. The green body obtained by molding the powder can be sintered at 1250℃ without heat preservation to obtain a dense YAG nanocrystalline ceramic with a relative density of 99.6%. Its SEM image is shown in Figure 3 .

[0116] Example 2

[0117] This embodiment provides a method for preparing YAG nanopowder with high sintering activity, and the steps are as follows:

[0118] 1. Weigh a certain amount of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate respectively and dissolve them in 200 ml of deionized water. Stir continuously to fully dissolve the nitrate to obtain Y 3+ and Al 3+ Mixed solutions with ion concentrations of 0.12 mol / L and 0.2 mol / L;

[0119] 2. Add 2 g PEG-4000 as a dispersant to the mixed solution, stir to completely dissolve it, and stir the clarified mixed solution for 30 min;

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

[0121] 4. The gel obtained in step 3 was placed in an oven at 70°C to completely dry, then taken out and ground to a particle size of 450 μm to obtain a precursor powder; the precursor was calcined at 900°C for 3h to obtain an initial YAG powder;

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

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

[0124] The X-ray diffraction spectrum of the obtained product was compared with the standard spectrum to confirm that it was a pure YAG phase. Figure 4 As shown in the figure, the obtained YAG nanoparticles are completely dispersed, there is no hard agglomeration between the particles, the particle shape is equiaxed, the size is small, the statistical average particle size is 8nm, and the size distribution is 3-36nm. The high-resolution transmission electron microscopy image of the obtained sample is shown in the figure Figure 5As shown, the obtained particles are cubic phases, and no obvious defects are observed therein. The green body obtained by molding the powder is sintered at 1250°C without heat preservation to obtain dense YAG nanocrystalline ceramics with a relative density of 99.6%.

[0125] Example 3

[0126] This embodiment provides a method for preparing YAG nanopowder with high sintering activity, and the steps are as follows:

[0127] 1. Weigh a certain amount of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate respectively and dissolve them in 200 ml of deionized water. Stir continuously to fully dissolve the nitrate to obtain Y 3+ and Al 3+ Mixed solutions with ion concentrations of 0.12 mol / L and 0.2 mol / L;

[0128] 2. Add 4 g PEG-4000 as a dispersant to the mixed solution, stir to completely dissolve it, and stir the clarified mixed solution for 30 min;

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

[0130] 4. The gel obtained in step 3 was placed in an oven at 70°C to completely dry, then taken out and ground to a particle size of 450 μm to obtain a precursor powder; the precursor was calcined at 900°C for 3h to obtain an initial YAG powder;

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

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

[0133] The obtained YAG nanoparticles are completely dispersed, there is no hard agglomeration between the particles, the particle shape is equiaxed, the size is small, the statistical average particle size is 9nm, and the size distribution is 3-38nm. The green body obtained by forming the powder is sintered at 1200℃ for 1h to obtain a dense YAG nanocrystalline ceramic with a relative density of 99.7%.

[0134] Example 4

[0135] This embodiment provides a method for preparing YAG nanopowder with high sintering activity, and the steps are as follows:

[0136] 1. Weigh a certain amount of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate respectively and dissolve them in 200 ml of deionized water. Stir continuously to fully dissolve the nitrate to obtain Y 3+ and Al 3+The mixed solutions have ion concentrations of 0.12 mol / L and 0.2 mol / L respectively; a certain amount of Ru(NO3)3 is weighed as a Ru source to achieve doping;

[0137] 2. Add 4 g PEG-4000 as a dispersant to the mixed solution, stir to completely dissolve it, and stir the clarified mixed solution for 30 min;

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

[0139] 4. The gel obtained in step 3 was placed in an oven at 70°C to completely dry, then taken out and ground to a particle size of 480 μm to obtain a precursor powder; the precursor was calcined at 900°C for 3h to obtain an initial YAG powder;

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

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

[0142] The microscopic morphology of the obtained product is Figure 6 As shown. The obtained YAG nanoparticles are completely dispersed, there is no hard agglomeration between the particles, the particle shape is equiaxed, the size is small, the statistical average particle size is 7nm, and the size distribution is 3-35nm. The Ru content in the powder obtained by testing is 0.05wt%. The green body obtained by molding the powder is sintered at 1250℃ for 30min to obtain a dense YAG nanocrystalline ceramic with a relative density of 99.7%.

[0143] Example 5

[0144] This embodiment provides a method for preparing YAG nanopowder with high sintering activity, and the steps are as follows:

[0145] 1. Weigh a certain amount of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate respectively and dissolve them in 200 ml of deionized water. Stir continuously to fully dissolve the nitrate to obtain Y 3+ and Al 3+ The mixed solutions have ion concentrations of 0.18 mol / L and 0.3 mol / L respectively; a certain amount of Ce(NO3)3 is weighed as a Ce source to achieve doping;

[0146] 2. Add 8 g PEG-4000 as a dispersant to the mixed solution, stir to completely dissolve it, and stir the clarified mixed solution for 30 min;

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

[0148] 4. The gel obtained in step 3 was placed in an oven at 70°C to completely dry, and then taken out and ground to a particle size of 400 μm to obtain a precursor powder; the precursor was calcined at 900°C for 3h to obtain an initial YAG powder;

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

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

[0151] The microscopic morphology of the obtained product is Figure 7 As shown. The obtained YAG nanoparticles are completely dispersed, there is no hard agglomeration between the particles, the particle shape is equiaxed, the size is small, the statistical average particle size is 8nm, and the size distribution is 3-38nm. The Ce content in the powder obtained by testing is 0.01wt%. The green body obtained by molding the powder is sintered at 1200℃ for 1h to obtain a dense YAG nanocrystalline ceramic with a relative density of 99.7%.

[0152] Example 6

[0153] This embodiment provides a method for preparing YAG nanopowder with high sintering activity, and the steps are as follows:

[0154] 1. Weigh a certain amount of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate respectively and dissolve them in 200 ml of deionized water. Stir continuously to fully dissolve the nitrate to obtain Y 3+ and Al 3+ Mixed solutions with ion concentrations of 0.3 mol / L and 0.5 mol / L;

[0155] 2. Add 8 g PEG-4000 as a dispersant to the mixed solution, stir to completely dissolve it, and stir the clarified mixed solution for 30 min;

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

[0157] 4. The gel obtained in step 3 was placed in an oven at 70°C to completely dry, then taken out and ground to a particle size of 450 μm to obtain a precursor powder; the precursor was calcined at 950°C for 3 h to obtain an initial YAG powder;

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

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

[0160] The obtained YAG nanoparticles are completely dispersed, there is no hard agglomeration between the particles, the particle shape is equiaxed, the size is small, the statistical average particle size is 9nm, and the size distribution is 3-37nm. The green body obtained by molding the powder can be sintered at 1250℃ without heat preservation to obtain a dense YAG nanocrystalline ceramic with a relative density of 99.6%. The scanning electron microscope image of the obtained dense YAG nanocrystalline ceramic is as follows Figure 8 shown.

[0161] Example 7

[0162] This embodiment provides a method for preparing YAG nanopowder with high sintering activity, and the steps are as follows:

[0163] 1. Dissolve the commercially available yttrium oxide powder with a quantitative purity of 99.9% in a concentrated nitric acid aqueous solution at room temperature to obtain an aqueous solution of yttrium nitrate with a specific concentration. Weigh the commercially available aluminum oxide powder with a quantitative purity of 99.9%, add it to concentrated nitric acid and continue stirring at 90°C until it is completely dissolved to obtain an aqueous solution of aluminum nitrate with a specific concentration;

[0164] 2. Mix the obtained nitrate aqueous solution in a specific ratio and continue stirring to make the nitrate evenly mixed to obtain Y 3+ and Al 3+ Mixed solutions with ion concentrations of 0.3 mol / L and 0.5 mol / L;

[0165] 3. Add 4 g PEG-4000 as a dispersant to the mixed solution, stir to completely dissolve it, and stir the clarified mixed solution for 30 min;

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

[0167] 4. The gel obtained in step 3 was placed in an oven at 70°C to completely dry, then taken out and ground to a particle size of 490 μm to obtain a precursor powder; the precursor was calcined at 900°C for 3 h to obtain an initial YAG powder;

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

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

[0170] The obtained product is pure YAG phase. The obtained YAG nanoparticles are completely dispersed, there is no hard agglomeration between the particles, the particle shape is equiaxed, the size is small, the statistical average particle size is 9nm, and the size distribution is 3-30nm. The green body obtained by forming the powder is sintered at 1200℃ for 1h to obtain a dense YAG nanocrystalline ceramic with a relative density of 99.5%. The scanning electron microscope image of the dense YAG nanocrystalline ceramic obtained by sintering is shown in Fig. 9 shown.

[0171] Comparative Example 1

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

[0173] 1. Weigh a certain amount of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate respectively and dissolve them in 200 mL of deionized water. Stir continuously to fully dissolve the nitrate. Confirm the cation concentration by ICP test to obtain Y 3+ and Al 3+ Mixed solutions with ion concentrations of 0.12 mol / L and 0.2 mol / L;

[0174] 2. Add 8 g PEG-4000 as a dispersant to the mixed solution, stir to completely dissolve it, and stir the clarified mixed solution for 30 min;

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

[0176] 4. The gel obtained in step 3 is placed in an oven at 70°C to completely dry it and then taken out to obtain a precursor; the precursor is calcined at 950°C for 2.5h to obtain an initial YAG powder;

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

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

[0179] The obtained YAG powder is black, with an average grain size of 10nm, a size distribution of 3-40nm, and dispersed particles. During the sintering process, a large number of intracrystalline pores will be generated in the green body obtained by molding. Its microscopic morphology is as follows: Fig.10 shown.

[0180] Comparative Example 2

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

[0182] 1. Weigh a certain amount of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate respectively and dissolve them in 200 mL of deionized water. Stir continuously to fully dissolve the nitrate. Confirm the cation concentration by ICP test to obtain Y 3+ and Al 3+ Mixed solutions with ion concentrations of 0.12 mol / L and 0.2 mol / L;

[0183] 2. Add 8 g PEG-4000 as a dispersant to the mixed solution, stir to completely dissolve it, and stir the clarified mixed solution for 30 min;

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

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

[0186] The YAG powder particles were severely agglomerated, with a particle size of 200-300 nm. Fig.11 The large pores in the green body obtained by forming it 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 are as follows:

[0189] 1. Weigh a certain amount of yttrium nitrate hexahydrate and aluminum nitrate nonahydrate respectively and dissolve them in 200 mL of deionized water. Stir continuously to fully dissolve the nitrate. Confirm the cation concentration by ICP test to obtain Y 3+ and Al 3+ Mixed solutions with ion concentrations of 0.12 mol / L and 0.2 mol / L;

[0190] 2. Add PEG-6000 and citric acid monohydrate (the molar ratio of the two is 1:2) to the mixed solution to obtain a mixed solution, wherein the content of PEG-6000 in the mixed solution is 8 wt %, and the mixed solution is continuously heated in a 90° C. water bath with continuous stirring to obtain a gel;

[0191] 3. After aging the gel obtained in step 2, transfer it to an oven for drying. After 12 hours, transfer it to a muffle furnace for thermal annealing at 1000°C for 2.5 hours to cause a self-propagating combustion reaction, and then grind it to obtain YAG.

[0192] The average grain size of the YAG powder is 318nm, the particle size is 250-650nm in length and 50-100nm in width, and there is serious agglomeration between the particles. The large pores in the green body obtained by forming it cannot be eliminated during the pressureless sintering process. Its microscopic morphology is as follows Fig.12 shown.

[0193] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0194] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A high sintering activity yttrium aluminum garnet nanopowder, characterized in that: The chemical formula of 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 high sintering activity yttrium aluminum garnet nano powder has an average particle size of 7-10 nm and a size distribution of 3-40 nm. It is an equiaxed cubic crystal. The high sintering activity yttrium aluminum garnet nano powder is completely dispersed and has no agglomeration.

2. The high sintering activity yttrium aluminum garnet nanopowder according to claim 1, characterized in that: The high sintering activity yttrium aluminum garnet nano powder is pressurelessly sintered at 1200-1300° C. to obtain yttrium aluminum garnet nanocrystalline ceramics; Optionally, the sintering time is 0-1h; Optionally, the density of the yttrium aluminum garnet nanocrystalline ceramic is 99.1%-99.7%.

3. The high sintering activity yttrium aluminum garnet nanopowder according to claim 1, characterized in that: x is 0-0.

02.

4. The high sintering activity yttrium aluminum garnet nanopowder according to claim 1, characterized in that: The yttrium aluminum garnet nanopowder is obtained by the following preparation method: The preparation method comprises the following steps: A mixed solution containing yttrium salt, aluminum salt and optional RE salt is prepared in a stoichiometric ratio; The mixed solution is mixed with a dispersant, and a precursor is obtained by heat treatment; The precursor is subjected to a first grinding process and a calcination process to obtain a powder; The powder is subjected to a second grinding process and a drying process to obtain the yttrium aluminum garnet nanopowder; Wherein, the RE salt is used to provide the doping element RE.

5. A method for preparing a high sintering activity yttrium aluminum garnet nanopowder, characterized in that: The chemical formula of 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 comprises the following steps: A mixed solution containing yttrium salt, aluminum salt and optional RE salt is prepared in a stoichiometric ratio; The mixed solution is mixed with a dispersant, and a precursor is obtained by heat treatment; The precursor is subjected to a first grinding process and a calcination process to obtain a powder; The powder is subjected to a second grinding process and a drying process to obtain the yttrium aluminum garnet nanopowder; Wherein, the RE salt is used to provide the doping element RE.

6. The preparation method according to claim 5, characterized in that: The concentration of yttrium salt in the mixed solution is 0.12-0.3 mol / L; Optionally, the concentration of the aluminum salt in the mixed solution is 0.2-0.5 mol / L.

7. The preparation method according to claim 5, characterized in that: The dispersant includes at least one of polyethylene glycol, ethanol, polyacrylamide, and ethylenediamine; Optionally, the volume mass ratio of the mixed solution to the dispersant is 200 mL:(2-8) g.

8. The preparation method according to claim 5, characterized in that: The heat treatment is carried out at 75-95°C; Optionally, the first grinding process is performed until the precursor particle size is 300-500 μm; Optionally, the calcination temperature is 900-1100°C; Optionally, the calcination treatment time is 2-5h; Optionally, the second grinding process is performed until the powder particle size is 3-40 nm.

9. The preparation method according to claim 5, characterized in that: The yttrium salt includes at least one of yttrium nitrate, yttrium acetate, yttrium chloride, and yttrium carbonate; Optionally, the aluminum salt includes at least one of aluminum nitrate, aluminum sulfate, and aluminum chloride; Optionally, the RE salt includes at least one of Ru(NO3)3, Ce(NO3)3, Tb(NO3)3, Nd(NO3)3, and Sm(NO3)3.

10. The preparation method according to claim 5, characterized in that: The average particle size of the yttrium aluminum garnet nanopowder is 7-10nm, the size distribution is 3-40nm, and it is an equiaxed cubic crystal. The yttrium aluminum garnet nanopowder is completely dispersed and has no agglomeration.

11. Use of the yttrium aluminum garnet nanopowder according to any one of claims 1 to 4 or the high sintering activity yttrium aluminum garnet nanopowder obtained by the preparation method according to any one of claims 5 to 10 for preparing yttrium aluminum garnet ceramic materials.

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