Whisker-reinforced aluminum nitride material and method of making

Abstract

The application discloses a whisker-reinforced aluminum nitride material and a preparation method thereof, and aims to solve the technical problem that the existing aluminum nitride material is difficult to improve the toughness and guarantee the stability of product quality. The application prepares two types of composite granulation particles: first composite particles are prepared by using aluminum nitride whiskers, nano aluminum nitride particles and a first sintering aid; second composite particles are prepared by using micro aluminum nitride particles and a second sintering aid; then the two types of composite particles are mixed, preformed, degassed and high-temperature sintered to obtain the whisker-reinforced aluminum nitride material. The application uses nano aluminum nitride particles to fill the gaps between aluminum nitride whiskers, significantly improves the fracture toughness of the aluminum nitride material; the mixing of the composite particles can avoid the uneven distribution problem of aluminum nitride whiskers and nano powder caused by the difference in morphology and fluidity, and improve the consistency of batch product performance and the stability of the preparation process. The whisker-reinforced aluminum nitride material can be widely applied in the fields of high-thermal-conductivity electronic packaging and the like.

Description

Technical Field

[0001] This invention relates to the field of ceramic materials technology, and in particular to a whisker-reinforced aluminum nitride material and its preparation method. Background Technology

[0002] 5G and intelligent technologies have driven the miniaturization and integration of electronic devices, and the resulting high heat flux density has made heat dissipation design a key limiting factor for device performance.

[0003] Aluminum nitride (ANT) materials are widely used in various heat dissipation applications due to their non-toxicity, excellent thermal conductivity, and suitable coefficient of thermal expansion. However, traditional ANT materials face challenges in application, including low toughness and limited strength. In related technologies, ANT whiskers, diamond whiskers, and silicon nitride whiskers have been used to improve the strength of ANT materials. However, the poor interfacial bonding between diamond whiskers and ANT makes it difficult to significantly improve the thermal conductivity and toughness of ANT materials. The addition of silicon nitride whiskers can improve substrate toughness to some extent, but it significantly reduces the substrate's thermal conductivity, making it impossible to achieve both simultaneously. ANT whiskers are considered an excellent candidate filler for reinforcement and toughening; however, in practice, the effects of adding ANT whiskers are unstable, making it difficult to balance thermal conductivity and toughness, resulting in poor product quality stability. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a whisker-reinforced aluminum nitride material and its preparation method, aiming to at least improve one of the problems existing in the prior art.

[0005] The first aspect of the present invention provides a method for preparing a whisker-reinforced aluminum nitride material, the method comprising: Granulation process: Prepare a first composite particle containing aluminum nitride whiskers, nano-aluminum nitride particles and a first sintering aid, and prepare a second composite particle containing micron-sized aluminum nitride particles and a second sintering aid; Mixing process: The first composite particles and the second composite particles are mixed to obtain mixed particles; Preforming process: The mixed particles are preformed to obtain a preformed blank; Glue removal process: The preform is subjected to glue removal treatment to obtain a glue-removed preform; Sintering process: The debonded preform is sintered to obtain whisker-reinforced aluminum nitride material.

[0006] In some embodiments, the first sintering aid and the second sintering aid are each independently one or more of Y2O3, CaO, CaF2, Sm2O3, and Yb2O3.

[0007] In some embodiments, the second sintering aid is Y2O3 and CaF2, the first sintering aid is Y2O3, and the molar ratio of Y2O3 to CaF2 in the second sintering aid is controlled at 1:1-3:1.

[0008] In some embodiments, the particle size D50 of the nano-aluminum nitride particles is 160-300 nm, the particle size D50 of the micron-aluminum nitride particles is 0.8-1.5 μm, the diameter of the aluminum nitride whiskers is 0.1-1.2 μm, and the aspect ratio is 5-25.

[0009] In some implementations, the weight percentage of the first composite particle in the mixed particles is 20%-70%.

[0010] In some embodiments, the preforming is at least one of dry pressing and cold isostatic pressing; the debinding temperature is 500°C to 700°C; and the sintering temperature is 1500°C to 1750°C.

[0011] In some embodiments, the step of preparing the first composite particles comprising aluminum nitride whiskers, nano-aluminum nitride particles, and a first sintering aid includes: mixing and dispersing aluminum nitride whiskers, nano-aluminum nitride particles, the first sintering aid, a dispersant, a binder, and a solvent to obtain a first dispersion slurry; and subjecting the first dispersion slurry to a first spray granulation treatment to obtain the first composite particles. The steps for preparing second composite particles comprising micron-sized aluminum nitride particles and a second sintering aid include: mixing and dispersing micron-sized aluminum nitride particles, a second sintering aid, a dispersant, a binder, and a solvent to obtain a second dispersion slurry; and subjecting the second dispersion slurry to a second spray granulation treatment to obtain the second composite particles.

[0012] In some embodiments, the amount of each raw material added to the first dispersion slurry by weight percentage is: 10%-20% aluminum nitride whiskers, 15%-30% nano-aluminum nitride particles, 0.5%-3% first sintering aid, 0.1%-1% dispersant, 1%-10% binder, and 40%-75% solvent; The addition amounts of each raw material in the second dispersion slurry are: 25%-50% micron-sized aluminum nitride particles, 2%-5% second sintering aid, 0.1%-1% dispersant, 1%-10% binder, and 40%-75% solvent.

[0013] In some embodiments, the weight percentage of the second sintering aid in the second dispersion slurry is 1%-4% higher than that of the first sintering aid in the first dispersion slurry.

[0014] In some embodiments, the dispersant is one or more of polyvinylpyrrolidone, fish oil, castor oil, and oleic acid; the binder is one or more of polyvinyl butyral, polyethylene glycol, and acrylic resin; and the solvent is one or more of ethanol and isopropanol.

[0015] A second aspect of the present invention provides a whisker-reinforced aluminum nitride material, which is prepared by the above method.

[0016] Compared with the prior art, the present invention has the following beneficial effects: During the molding process, nano-sized aluminum nitride particles are mainly distributed around the aluminum nitride whiskers. These nano-sized particles help fill the irregular gaps around the aluminum nitride whiskers, resulting in higher density and reducing internal defects caused by incomplete filling. Furthermore, with the combined effect of the first sintering aid, the nano-sized aluminum nitride particles result in smaller grains after molding, which is more conducive to preventing brittle fracture of the aluminum nitride whiskers under stress and improving toughness. Moreover, by mixing the first and second composite particles, since both are secondary particles formed by granulation, the uneven distribution problem caused by the large differences in morphology and flowability between aluminum nitride whiskers and nanoparticles can be improved to a certain extent. This improves uniformity, enhances product stability, and avoids performance degradation caused by uneven distribution of nano-whiskers. Simultaneously, the addition of second composite particles containing micron-sized aluminum nitride particles and the second sintering aid further improves the thermal conductivity of the whisker-reinforced aluminum nitride material.

[0017] Other further beneficial effects of the present invention can be seen in the description of the specific embodiments. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0019] Figure 1 These are optical microscope images of the preform prepared in Example 1; Figure 2 This is an optical microscope photograph of the first composite particle in Preparation Example 1; Figure 3 These are optical microscope images of the mixed particles from Preparation Example 1; Figure 4 The results are from the bending strength test in Example 1. Detailed Implementation

[0020] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0021] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0022] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0023] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, optionally sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0024] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" may also include or contain other components not listed, or may include only or contain the listed components.

[0025] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0026] In this article, in the semantic context of representing time, "h" represents hours.

[0027] As mentioned above, in the relevant technologies, there is a problem that it is difficult to improve the thermal conductivity and toughness of aluminum nitride materials at the same time, resulting in poor product quality stability.

[0028] In view of this, a first aspect of the present invention provides a method for preparing a whisker-reinforced aluminum nitride material, the method comprising: Granulation process: Prepare a first composite particle containing aluminum nitride whiskers, nano-aluminum nitride particles and a first sintering aid, and prepare a second composite particle containing micron-sized aluminum nitride particles and a second sintering aid; Mixing process: The first composite particles and the second composite particles are mixed to obtain mixed particles; Preforming process: The mixed particles are preformed to obtain a preformed blank; Glue removal process: The preform is subjected to glue removal treatment to obtain a glue-removed preform; Sintering process: The debonded preform is sintered to obtain whisker-reinforced aluminum nitride material.

[0029] In this embodiment of the invention, aluminum nitride whiskers, nano-aluminum nitride particles, and a first sintering aid are first combined to obtain a first composite particle. Then, micron-sized aluminum nitride particles and the second sintering aid are granulated to prepare a second composite particle. Finally, the first and second composite particles are mixed and molded. On one hand, during the molding process, nano-aluminum nitride particles are mainly distributed around the aluminum nitride whiskers. These nano-aluminum nitride particles help fill the irregular gaps around the aluminum nitride whiskers, resulting in higher density. On the other hand, under the combined action of the first sintering aid, the nano-aluminum nitride particles have smaller grains after molding, which is more conducive to avoiding brittle fracture of the aluminum nitride whiskers under stress and improving toughness. Furthermore, by mixing the first and second composite particles, since both are secondary particles formed by granulation, the uneven distribution problem caused by the large differences in morphology and flowability between aluminum nitride whiskers and nanoparticles can be improved to a certain extent. This improves uniformity, enhances product stability, and avoids performance degradation caused by uneven distribution of nano-whiskers. Meanwhile, by adding a second composite particle containing micron-sized aluminum nitride particles and a second sintering aid, the thermal conductivity of whisker-reinforced aluminum nitride materials can be further improved.

[0030] It should be noted that, in addition to the components mentioned above, the first composite particles and the second composite particles may also contain other components.

[0031] It is understood that there are various methods for preparing the first composite particles and the second composite particles. Optional methods include extrusion granulation and spray granulation, and other suitable granulation methods can also be used, which will not be listed here. The preparation methods for the first composite particles and the second composite particles can be different or the same, but it is preferable to use the same preparation method. Using the same preparation method is beneficial for preparing particles with similar morphologies, and similar morphologies facilitate uniform mixing of the two.

[0032] In some preferred embodiments, the method for preparing the first composite particles and the second composite particles is spray granulation.

[0033] The purpose of spray granulation is to prepare composite particles. For example, the inlet air temperature of spray granulation is 180℃-210℃, and the speed of the atomizing disc is 12000~18000 r / min.

[0034] In some embodiments, the first sintering aid and the second sintering aid are each independently one or more of Y2O3, CaO, CaF2, Sm2O3, and Yb2O3.

[0035] In some embodiments, the second sintering aid is Y₂O₃ and CaF₂, and the first sintering aid is Y₂O₃. The inclusion of these components in the second sintering aid helps to lower the sintering temperature of the second composite particles, bringing it closer to the sintering temperature of the first composite particles, thus achieving simultaneous densification of the two composite particles at a unified sintering temperature. Furthermore, the molar ratio of Y₂O₃ to CaF₂ is controlled between 1:1 and 3:1. Excessive CaF₂ content leads to an excessive amount of grain boundary phase, reducing thermal conductivity and strength; insufficient content fails to effectively regulate the sintering behavior of the second composite particles, hindering product consistency.

[0036] In some embodiments, the particle size D50 of the nano-aluminum nitride particles is 160-300 nm. Nano-aluminum nitride particles of suitable size are beneficial for filling the gaps between aluminum nitride whiskers. Excessively large particle sizes make effective filling difficult, while excessively small particle sizes, although capable of effective filling, significantly reduce the matching degree of sintering temperature and shrinkage. As an example, the particle size of the nano-aluminum nitride particles can be any value between 160 nm, 180 nm, 200 nm, 220 nm, 250 nm, 280 nm, 300 nm, 160-220 nm, 160-250 nm, 200-280 nm, or 160-300 nm, or any range consisting of any two of the above values.

[0037] In some embodiments, the particle size D50 of the micron-sized aluminum nitride particles is 0.8-1.5 μm. As an example, the particle size of the micron-sized aluminum nitride particles can be any value between 0.8 μm, 1 μm, 1.2 μm, 1.4 μm, 1.5 μm, 0.8-1.4 μm, 0.8-1.2 μm, 0.8-1 μm, or 0.8-1.5 μm, or a range consisting of any two of the above values.

[0038] In some embodiments, the aluminum nitride whiskers have a diameter of 0.1-1.2 μm and an aspect ratio of 5-25.

[0039] In some embodiments, the weight percentage of the first composite particle in the mixed particles is 20%-70%. For example, the weight percentage of the first composite particle in the mixed particles is any value or range within the range of 20%, 30%, 40%, 50%, 60%, 70%, or 20%-70%.

[0040] It should be understood that the preforming process is to form the mixed particles into a preform.

[0041] In some embodiments, preforming can be selected as dry pressing or cold isostatic pressing. Dry pressing and cold isostatic pressing have good compatibility with mixed particles. It is understood that other suitable forming methods can also be used in the preforming process.

[0042] In some embodiments, the temperature of the degumming process is 500°C to 700°C.

[0043] In some embodiments, the sintering temperature is 1500℃ to 1750℃. In this application, the sintering temperature needs to comprehensively consider the sintering behavior of the first composite particle and the second composite particle. Excessive temperature leads to an excessively rapid shrinkage rate of the first composite particle, resulting in a mismatch in the system's shrinkage behavior and potentially causing a decrease in product stability. Insufficient temperature may lead to incomplete sintering and a significant decrease in flexural strength. As an example, the sintering temperature can be 1500℃, 1550℃, 1600℃, 1650℃, 1700℃, 1750℃, 1600℃-1650℃, 1650℃-1700℃, or any value within the range of 1500℃ to 1750℃, or any other arbitrary range.

[0044] In some embodiments, the step of preparing the first composite particle comprising aluminum nitride whiskers, aluminum nitride nanoparticles, and a first sintering aid includes: Aluminum nitride whiskers, nano-aluminum nitride particles, a first sintering aid, a dispersant, a binder, and a solvent are mixed and dispersed to obtain a first dispersion slurry; The first dispersion slurry is subjected to a first spray granulation treatment to obtain the first composite particles.

[0045] In some embodiments, the step of preparing a second composite particle comprising micron-sized aluminum nitride particles and a second sintering aid includes: mixing and dispersing micron-sized aluminum nitride particles, a second sintering aid, a dispersant, a binder, and a solvent to obtain a second dispersion slurry; The second dispersion slurry is subjected to a second spray granulation treatment to obtain the second composite particles.

[0046] It should be understood that during the preparation of the first and second composite particles, the mixing and dispersion are to ensure that the aluminum nitride whiskers, nano-aluminum nitride particles, and micron-sized aluminum nitride particles are uniformly dispersed with other components. Different dispersion methods can be adopted; for example, one or more of stirring dispersion, ultrasonic dispersion, and ball milling dispersion can be used.

[0047] Optionally, a combination of stirring and ultrasonic dispersion can be used for mixing and dispersion. The combination of high-speed stirring and ultrasonic dispersion can avoid the breakage of aluminum nitride whiskers caused by ball milling, and can maintain the morphology of aluminum nitride whiskers to a certain extent, thereby improving the toughening effect.

[0048] Optionally, ball milling is used for mixing and dispersion. Further, when using ball milling for mixing and dispersion, the milling time is 2-36 hours, and even more specifically, 6-12 hours. A suitable milling time is beneficial for the uniform and stable dispersion of aluminum nitride whiskers and nano-aluminum nitride particles. Too short a milling time may result in uneven dispersion, while too long a milling time leads to low production efficiency, and the aluminum nitride whiskers may break due to milling, affecting their toughening effect. Since the first and second composite particles are mixed before preforming in this invention, the dispersibility of the aluminum nitride whiskers can be improved, thereby reducing the requirements for ball milling dispersion to a certain extent. This allows for a shorter milling time, further reducing energy consumption and improving production efficiency, while also preserving the morphology of the aluminum nitride whiskers as much as possible, reducing whisker breakage caused by milling, and further enhancing the whisker toughening effect.

[0049] In some embodiments, the amount of each raw material added to the first dispersion slurry by weight percentage is: 10%-20% aluminum nitride whiskers, 15%-30% nano aluminum nitride particles, 0.5%-3% first sintering aid, 0.1%-1% dispersant, 1%-10% binder, and 40%-75% solvent.

[0050] In some embodiments, the amount of each raw material added to the second dispersion slurry by weight percentage is: 25%-50% micron-sized aluminum nitride particles, 2%-5% second sintering aid, 0.1%-1% dispersant, 1%-10% binder, and 40%-75% solvent.

[0051] In some embodiments, the weight percentage of the second sintering aid in the second dispersion slurry is higher than the weight percentage of the first sintering aid in the first dispersion slurry. In some further embodiments, the weight percentage of the second sintering aid in the second dispersion slurry is 1%-4% higher than the weight percentage of the first sintering aid in the first dispersion slurry.

[0052] In some embodiments, the dispersant is one or more of polyvinylpyrrolidone (PVP), fish oil, castor oil, and oleic acid.

[0053] In some embodiments, the adhesive is one or more of polyvinyl butyral (PVB), polyethylene glycol (PEG), and acrylic resin.

[0054] In some embodiments, the solvent is one or more of ethanol and isopropanol.

[0055] A second aspect of the present invention provides a whisker-reinforced aluminum nitride material, which is prepared by the above method.

[0056] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all reagents and raw materials used in the embodiments are commercially available or synthesized by conventional methods, and the instruments used in the embodiments are also commercially available.

[0057] In the following examples, both the nano-aluminum nitride particles and the micron-sized aluminum nitride particles were self-made.

[0058] Aluminum nitride whiskers were purchased from Nangong Fenghui Nanotechnology Co., Ltd.

[0059] In the following embodiments, a metallographic microscope was used to characterize the microstructure; a computer-controlled servo material testing machine was used to characterize the bending strength.

[0060] Example 1 of the preparation of the first composite particle 18% aluminum nitride whiskers, 30% nano aluminum nitride particles, 1.2% first sintering aid Y2O3, 1% dispersant PVP, 8% binder PVB, and 41.8% solvent ethanol were mixed and dispersed, ball-milled for 6 hours, and ultrasonically dispersed for 2 hours to obtain the first dispersion slurry. The first dispersion slurry is subjected to a first spray granulation treatment. The spray granulation hot air temperature is 190℃, the outlet temperature is 100℃, and the feed rate is 5L / h.

[0061] Example 2 of the preparation of the second composite particles 48% micron-sized aluminum nitride particles, 1% Y2O3 (second sintering aid), 2% CaF2, 1% PEG (dispersant), 5% PVB (binder), and 43% ethanol (solvent) were mixed and dispersed, and ball-milled for 12 hours to obtain a second dispersion slurry. The second dispersion slurry is subjected to a second spray granulation treatment. The spray granulation hot air temperature is 190℃, the outlet temperature is 100℃, and the feed rate is 5L / h.

[0062] Example 3 of the preparation of the second composite particles 50% micron-sized aluminum nitride particles, 1% Y2O3 (second sintering aid), 1% PEG (dispersant), 5% PVB (binder), and 43% ethanol (solvent) were mixed and dispersed, and ball-milled for 12 hours to obtain a second dispersion slurry. The second dispersion slurry is subjected to a second spray granulation treatment. The spray granulation hot air temperature is 190℃, the outlet temperature is 100℃, and the feed rate is 5L / h.

[0063] Comparative Example 4: Preparation of Composite Particles 10.8% aluminum nitride whiskers, 18% nano aluminum nitride particles, 20% micron aluminum nitride particles, 1.2% first sintering aid Y2O3, 1% dispersant PVP, 8% binder PVB, and 41% solvent ethanol were mixed and dispersed, ball-milled for 6 hours, and ultrasonically dispersed for 2 hours to obtain a dispersion slurry. The dispersed slurry is subjected to a second spray granulation treatment. The spray granulation hot air temperature is 190℃, the outlet temperature is 100℃, and the feed rate is 5L / h.

[0064] The preparation method of whisker-reinforced aluminum nitride material is as follows: In the mixing process, a can mill is used to mix the first composite particles and the second composite particles to obtain mixed particles; The preforming process involves preforming the mixed particles (dry pressing) to obtain a preformed blank. In the glue removal process, the preform is treated with glue removal (680℃) to obtain a glue-removed preform. In the sintering process, the debonded preform is sintered (1600℃, heating rate 2℃ / min, holding time 5h) to obtain whisker-reinforced aluminum nitride material.

[0065] In the following embodiments, product quality stability is characterized by the following methods: Five parallel test samples of whisker-reinforced aluminum nitride materials from each embodiment / comparative example were selected for three-point flexural strength testing. All samples underwent uniform grinding and polishing before testing. The flexural strength was measured using a universal testing machine under identical testing conditions, and the measured flexural strength data for each group of five samples were recorded. Sample variance was used to characterize the fluctuation of the flexural strength of each group of samples, thereby evaluating the stability of the mechanical properties of the samples under different preparation processes.

[0066] The formula for calculating sample variance is as follows: In the formula: S 2 is the sample variance; n is the number of parallel samples in each group, in this example n=5; This represents the measured value of the flexural strength of the i-th sample. This is the arithmetic mean of the flexural strength of the five specimens in this group.

[0067] This application introduces the coefficient of variation ( The dispersion of mechanical properties of samples from different processes was compared laterally. The coefficient of variation is the ratio of the sample standard deviation to the arithmetic mean of the flexural strength within the corresponding group, and the calculation formula is as follows: ×100% of which, The coefficient of variation is 1. The standard deviation of the sample is 1. The coefficient of variation is the arithmetic mean of the bending strength of a set of parallel specimens. The smaller the coefficient of variation, the smaller the relative fluctuation of the bending strength of the specimens in this example, and the better the consistency of mechanical properties and process repeatability of the batch products; conversely, the greater the performance fluctuation, the worse the stability of the preparation process.

[0068] Example 1 By weight percentage, 60% of the first composite particles obtained in Preparation Example 1 and 40% of the second composite particles obtained in Preparation Example 2 were mixed and prepared according to the above preparation process to obtain whisker-reinforced aluminum nitride material. Five groups of whisker-reinforced aluminum nitride material samples were taken for measurement. The average bending strength of the samples was... 472.784 MPa; Sample standard deviation 16.115 MPa, sample coefficient of variation 3.41%. Specific test data are shown in Table 1 below: Table 1: Bending Strength Data of Example 1 Example 2 By weight percentage, 60% of the first composite particles obtained in Preparation Example 1 and 40% of the second composite particles obtained in Preparation Example 3 were mixed and prepared according to the above preparation process to obtain whisker-reinforced aluminum nitride material. Five groups of whisker-reinforced aluminum nitride material samples were taken for measurement. The average bending strength of the samples was... 448.533 MPa; Sample standard deviation 24.636 MPa, sample coefficient of variation 5.49%.

[0069] Example 3 By weight percentage, 30% of the first composite particles obtained in Preparation Example 1 and 70% of the second composite particles obtained in Preparation Example 3 were mixed and prepared according to the above preparation process to obtain whisker-reinforced aluminum nitride material. Five groups of whisker-reinforced aluminum nitride material samples were taken for measurement. The average bending strength of the samples was... 448.319 MPa; Sample standard deviation 13.264 MPa, sample coefficient of variation 2.96%.

[0070] Comparative Example 1 Based on weight percentage, the comparative composite particles obtained in Preparation Example 4 were used to prepare whisker-reinforced aluminum nitride materials according to the above preparation process. Five groups of whisker-reinforced aluminum nitride material samples were then measured. The average flexural strength of the samples was... 441.442 MPa; Sample standard deviation 35.466 MPa, sample coefficient of variation : 8.03%.

[0071] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0072] The embodiments described above are merely illustrative of several implementations of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing a whisker-reinforced aluminum nitride material, characterized in that, The preparation method includes: Granulation process: Prepare a first composite particle containing aluminum nitride whiskers, nano-aluminum nitride particles and a first sintering aid, and prepare a second composite particle containing micron-sized aluminum nitride particles and a second sintering aid, wherein the first sintering aid and the second sintering aid are independently one or more of Y2O3, CaO, CaF2, Sm2O3 and Yb2O3. Mixing process: The first composite particles and the second composite particles are mixed to obtain mixed particles; Preforming process: The mixed particles are preformed to obtain a preformed blank; Glue removal process: The preform is subjected to glue removal treatment to obtain a glue-removed preform; Sintering process: The debonded preform is sintered to obtain whisker-reinforced aluminum nitride material.

2. The method for preparing whisker-reinforced aluminum nitride material according to claim 1, characterized in that: The second sintering aid is Y2O3 and CaF2, the first sintering aid is Y2O3, and the molar ratio of Y2O3 to CaF2 in the second sintering aid is controlled at 1:1-3:

1.

3. The method for preparing whisker-reinforced aluminum nitride material according to claim 1, characterized in that, The nano-sized aluminum nitride particles have a particle size D50 of 160-300 nm, the micro-sized aluminum nitride particles have a particle size D50 of 0.8-1.5 μm, the aluminum nitride whiskers have a diameter of 0.1-1.2 μm, and an aspect ratio of 5-25.

4. The method for preparing whisker-reinforced aluminum nitride material according to claim 1, characterized in that, The weight percentage of the first composite particle in the mixed particles is 20%-70%.

5. The method for preparing whisker-reinforced aluminum nitride material according to claim 1, characterized in that, The preform is at least one of dry pressing and cold isostatic pressing. The temperature for the glue removal process is 500℃~700℃; The sintering temperature is 1500℃~1750℃.

6. The method for preparing whisker-reinforced aluminum nitride material according to any one of claims 1-5, characterized in that: The step of preparing the first composite particles comprising aluminum nitride whiskers, nano-aluminum nitride particles, and a first sintering aid includes: mixing and dispersing the aluminum nitride whiskers, the nano-aluminum nitride particles, the first sintering aid, a dispersant, a binder, and a solvent to obtain a first dispersion slurry; and subjecting the first dispersion slurry to a first spray granulation treatment to obtain the first composite particles. The step of preparing the second composite particles comprising micron-sized aluminum nitride particles and a second sintering aid includes: mixing and dispersing the micron-sized aluminum nitride particles, the second sintering aid, a dispersant, a binder, and a solvent to obtain a second dispersion slurry; and subjecting the second dispersion slurry to a second spray granulation treatment to obtain the second composite particles.

7. The method for preparing whisker-reinforced aluminum nitride material according to claim 6, characterized in that: The amounts of each raw material added to the first dispersion slurry by weight percentage are as follows: 10%-20% aluminum nitride whiskers, 15%-30% nano-aluminum nitride particles, 0.5%-3% of the first sintering aid, 0.1%-1% of the dispersant, 1%-10% of the binder, and 40%-75% of the solvent; The addition amounts of each raw material in the second dispersion slurry are as follows: 25%-50% of the micronized aluminum nitride particles, 2%-5% of the second sintering aid, 0.1%-1% of the dispersant, 1%-10% of the binder, and 40%-75% of the solvent.

8. The method for preparing whisker-reinforced aluminum nitride material according to claim 7, characterized in that: The weight percentage of the second sintering aid in the second dispersion slurry is 1%-4% higher than that of the first sintering aid in the first dispersion slurry.

9. The method for preparing whisker-reinforced aluminum nitride material according to claim 6, characterized in that: The dispersant is one or more of polyvinylpyrrolidone, fish oil, castor oil, and oleic acid; the binder is one or more of polyvinyl butyral, polyethylene glycol, and acrylic resin; and the solvent is one or more of ethanol and isopropanol.

10. A whisker-reinforced aluminum nitride material, characterized in that, The whisker-reinforced aluminum nitride material is prepared by the preparation method according to any one of claims 1-9.

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