High-entropy boride ceramic beads, and preparation method and application thereof

Abstract

This invention discloses a high-entropy boride ceramic microsphere, its preparation method, and its application. The ceramic microsphere is prepared from the following components in parts by weight: 30-65 parts boride powder, 0.4-1.5 parts binder, 0.1-1.5 parts pH adjuster, 0.1-1.5 parts defoamer, and 0.6-1.5 parts dispersant. The ceramic microsphere of this invention has a sphericity of not less than 90%, a diameter range of 30-80 μm, and the content of impurity oxygen and impurity carbon in the ceramic microsphere is less than 1 wt%. The ceramic microsphere of this invention can be used to prepare high-entropy boride ceramic coatings using thermal spraying processes.

Description

Technical Field

[0001] This invention belongs to the field of ultra-high temperature ceramic materials technology, and relates to a high-entropy boride ceramic microsphere, its preparation method and application. Background Technology

[0002] Transition metal refractory boride ceramics possess excellent properties such as high melting point, high hardness, high chemical stability, high electrical conductivity, low coefficient of thermal expansion, and high wear resistance, making them widely used in refractory materials, aerospace, and nuclear industries. High-entropy boride ceramics are single-phase solid solution ceramics formed by five or more transition metal borides. They retain a hexagonal crystal structure with alternating two-dimensional boron and metal layers, where metal atoms randomly occupy metal sites in the metal layers. By adjusting the type and content of the metals, the properties of high-entropy boride ceramics can be controlled.

[0003] In 2016, Gild et al. from the University of California, San Diego (Scientific Reports 2016, 6, 1-10) successfully prepared seven pentagonal high-entropy boride ceramics using transition metal diborides as raw materials via spark plasma sintering. However, due to the use of commercially available boride raw materials, the purity of the materials was limited. Furthermore, the ultra-high melting point and strong covalent bonds of boride ceramics resulted in most of the prepared high-entropy borides exhibiting uneven elemental distribution, even though XRD characterization revealed a single-phase solid solution structure. To address the issue of raw material purity, researchers began to attempt to synthesize the raw materials themselves. This involved first synthesizing powders with a certain solid solubility and low oxygen content, and then hot-pressing or plasma sintering to prepare high-entropy boride bulks. For example, Zhang et al. (Journal of the European Ceramic Society, 2019, 39, 3920-3924) first prepared boride powder by boron carbide thermal reduction at 1600℃ using metal oxides, boron carbide, and carbon powder as raw materials, and then successfully prepared high-entropy boride ceramics with a density of up to 98.5% by SPS at 2000℃. Liu et al. (Scripta Materialia, 2019, 167, 110-114) started from metal oxides and boron powder and prepared (Hf) particles with a particle size of ~310nm at 1700℃. 0.2 Zr 0.2 Ta 0.2 Nb 0.2 Ti 0.2The high-entropy boride powder was prepared using boron carbide and metal oxides as raw materials at 1700℃. The powder contained very low levels of oxygen and carbon impurities, at 0.64% and 0.04%, respectively. Our research team (CN 116284804A, CN 114988881B) previously prepared a series of high-entropy boride powders from precursors, exhibiting uniform elemental distribution and particle sizes ranging from 100 nm to 1 μm. (Note: The text also mentions a team at Wuhan University of Technology, Gu, Science China Materials, 2019, 62, 1898-1909, who prepared high-entropy boride powders with very low oxygen and carbon impurity content, at 0.64% and 0.04%, respectively.)

[0004] However, most reported high-entropy boride ceramics are currently in powder or dense ceramic bulk form. For C / C materials, preparing ablation-resistant coatings for ultra-high temperature ceramics to improve their ablation performance under high-temperature oxidizing environments remains the preferred material protection strategy. Therefore, the development of high-entropy boride microspheres suitable for thermal spraying (plasma spraying, supersonic flame spraying, etc.) is urgently needed. In view of this, the present invention is proposed. Summary of the Invention

[0005] To improve the above-mentioned technical problems, the present invention provides a high-entropy boride ceramic microsphere, its preparation method and application. The high-entropy boride microsphere prepared by the present invention has good sphericity and can be used for thermal spraying to prepare high-entropy boride ceramic coatings.

[0006] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides a ceramic ball, which is prepared from the following components in parts by weight: 30-65 parts of boride powder, 0.4-1.5 parts of binder, 0.1-1.5 parts of pH adjuster, 0.1-1.5 parts of defoamer, and 0.6-1.5 parts of dispersant.

[0008] According to an embodiment of the present invention, the adhesive is selected from one or a mixture of several of gum arabic, polyvinyl alcohol, and polyacrylamide.

[0009] According to an embodiment of the present invention, the dispersant is, for example, polyethylene glycol, preferably polyethylene glycol with a number average molecular weight of 600 to 2000, exemplarily 600, 1000, 1500, 2000.

[0010] According to an embodiment of the present invention, the pH adjuster is selected from one or a mixture of several of citric acid, hydrochloric acid and glacial acetic acid.

[0011] According to an embodiment of the present invention, the defoamer is, for example, n-butanol.

[0012] According to an embodiment of the present invention, the sphericity of the ceramic sphere is not less than 90%, for example, 96%.

[0013] According to an embodiment of the present invention, the diameter of the ceramic ball is in the range of 30 to 80 μm, for example, 30 to 70 μm.

[0014] According to an embodiment of the present invention, the ceramic ball contains boron and also includes at least four of the following metallic elements: Ti, Zr, Hf, V, Nb, Ta, Mo, and W.

[0015] According to an embodiment of the present invention, in the ceramic sphere, the number of moles of each metal element is the same or different, and each element independently accounts for 5% to 35% of the total number of moles of metal in the ceramic sphere, for example, 5%, 10%, 15%, 20%, 30%, and 35%.

[0016] According to an embodiment of the present invention, the ratio of the total molar amount of the metal elements to the molar amount of boron is 1:2.0 to 2.2.

[0017] According to an embodiment of the present invention, the oxygen and carbon content in the ceramic spheres is both less than 1 wt%, for example, 0.5 wt%, 0.6 wt%, 0.7 wt%, or 0.8 wt%.

[0018] According to an embodiment of the present invention, the ceramic sphere is a high-entropy boride ceramic sphere, preferably a high-entropy boride ceramic microsphere. For example, the high-entropy boride ceramic microsphere is a solid solution with a hexagonal crystal phase structure.

[0019] According to an embodiment of the present invention, the ceramic ball is prepared by spray granulation of a slurry containing the above-mentioned components.

[0020] According to an embodiment of the present invention, the mass percentage of boride powder in the slurry is 30wt% to 65wt%; exemplary examples are 30wt%, 45wt%, 55wt%, and 65wt%.

[0021] According to an embodiment of the present invention, the mass percentage of the adhesive in the slurry is 0.4wt% to 1.5wt%; exemplary values ​​are 0.4wt%, 0.5wt%, 0.8wt%, 1.0wt%, and 1.5wt%.

[0022] According to an embodiment of the present invention, the mass percentage of the dispersant in the slurry is 0.6 wt% to 1.5 wt%; exemplary examples are 0.6 wt%, 1 wt%, and 1.5 wt%.

[0023] According to an embodiment of the present invention, the mass percentage of the pH adjuster in the slurry is 0.1 wt% to 1.5 wt%; exemplary values ​​are 0.1 wt%, 0.6 wt%, 1 wt%, and 1.5 wt%.

[0024] According to an embodiment of the present invention, the mass percentage of defoamer in the slurry is 0.1 wt% to 1.5 wt%; exemplary values ​​are 0.1 wt%, 0.6 wt%, 1 wt%, and 1.5 wt%.

[0025] According to an embodiment of the present invention, the slurry further includes a solvent. For example, the solvent is water.

[0026] According to an embodiment of the present invention, the sum of the weight percentages of the components in the slurry is 100%.

[0027] The present invention also provides a method for preparing the above-mentioned ceramic balls, comprising preparing the ceramic balls by spray granulation of a slurry containing the above-mentioned components.

[0028] According to an embodiment of the present invention, the granulation parameters of the spray granulation method are as follows: inlet air temperature 150℃~240℃, preferably 160℃~180℃, exemplarily 160℃; outlet air temperature 110℃~150℃, preferably 110℃~120℃, exemplarily 110℃ and 120℃; feed peristaltic pump speed 10~50rpm, preferably 30~45rpm, exemplarily 10rpm and 45rpm; atomizing disc frequency 35Hz~200Hz, preferably 150Hz~200Hz, exemplarily 150Hz and 180Hz.

[0029] According to an embodiment of the present invention, the material collection method of the spray granulation method is a three-point collection point, which includes material collection at the bottom of the drying tower, material collection by the primary cyclone separator, and material collection by the dust collector bag. The ceramic balls are obtained by material collection at the bottom of the drying tower.

[0030] According to an embodiment of the present invention, the boride powder is obtained by high-entropy boride precursor through high-temperature pyrolysis followed by ball milling.

[0031] In one embodiment of the present invention, the temperature of the high-temperature pyrolysis is 1500-1650℃, exemplarily 1500℃, 1600℃, 1650℃; the time of the high-temperature pyrolysis is 1-6h, exemplarily 1h, 2h, 3h, 4h, 6h.

[0032] In one embodiment of the present invention, the ball milling is dry milling, the ball-to-material ratio is 5 to 10:1, for example 5:1, 8:1, 10:1; the ball milling time is 5 to 10 hours, for example 5 hours, 6 hours, 8 hours, 10 hours; the ball mill speed is 200 to 350 rpm, for example 200 rpm, 300 rpm, 350 rpm.

[0033] According to embodiments of the present invention, the high-entropy boride precursor can be prepared by conventional methods known in the art. For example, it can be prepared according to the methods disclosed in CN116284804A and / or CN 114988881B.

[0034] According to an embodiment of the present invention, the preparation method further includes stirring and ball milling the slurry. For example, the ball-to-material ratio during ball milling is 5 to 10:1, exemplarily 5:1 or 10:1; the ball milling time is 5 to 10 hours, exemplarily 6 hours or 10 hours; and the ball mill speed is 200 to 350 rpm, exemplarily 300 rpm or 350 rpm.

[0035] According to an embodiment of the present invention, the preparation method further includes subjecting the ceramic balls obtained by spray granulation to a high-temperature solid solution reaction to obtain the ceramic balls. For example, the temperature of the high-temperature solid solution reaction is 1800℃~2000℃, exemplarily 1800℃, 1900℃, 2000℃; the time of the high-temperature solid solution reaction is 1-6h, exemplarily 1h, 2h, 3h, 4h, 6h.

[0036] According to an embodiment of the present invention, the preparation method includes the following steps:

[0037] (1) Preparation of boride powder: The high-entropy boride precursor was pyrolyzed at 1500-1650℃ and then ball-milled to obtain boride powder;

[0038] (2) Slurry preparation: Mix the solvent, binder, dispersant and pH adjuster, add defoamer while stirring, then add the boride powder obtained in step (1), ball mill, and prepare slurry;

[0039] (3) Spray granulation: The slurry obtained in step (2) is spray granulated to obtain boride ceramic balls;

[0040] (4) Solid solution reaction: The ceramic balls obtained in step (3) are subjected to a high-temperature solid solution reaction to obtain high-entropy boride ceramic balls.

[0041] The present invention also provides a coating comprising or made of the aforementioned ceramic spheres. For example, the coating is prepared by plasma spraying of the aforementioned ceramic spheres.

[0042] According to an embodiment of the present invention, the coating is a high-entropy boride ceramic coating.

[0043] The present invention also provides the use of the above-mentioned ceramic balls and / or coatings in the fields of ultra-high temperature components, high wear and corrosion resistant components, components resistant to molten metal corrosion, and neutron radiation protection devices.

[0044] The present invention also provides a component having the above-mentioned high-entropy boride ceramic spheres and / or coating disposed on its surface.

[0045] The beneficial effects of this invention:

[0046] High-entropy boride ceramic coatings possess excellent comprehensive properties, including high melting point, high hardness, high chemical stability, and high wear resistance and corrosion resistance. These superior characteristics make them extremely important coating materials in many engineering fields, such as ultra-high temperature components, highly wear- and corrosion-resistant components, components resistant to molten metal corrosion, and neutron radiation protection devices. This invention prepares high-entropy boride ceramic microspheres using a spray granulation method. The microspheres have high sphericity (≥90%) and moderate diameter (30–80 μm), making them suitable for spray coating preparation of high-entropy boride ceramic coatings. This invention optimizes the composition and ratio of the slurry during spray granulation, especially by adding a pH adjuster to adjust the isoelectric point of the slurry and adding an antifoaming agent to eliminate air bubbles in the slurry. Combined with optimized spray granulation process parameters, particularly the use of a three-point collection method to effectively separate ceramic microspheres from unformed powder, this invention achieves the controllable preparation of high-entropy boride ceramic microspheres with high sphericity (≥90%) and moderate diameter (30–80 μm). Attached Figure Description

[0047] Figure 1 This is the XRD pattern of the high-entropy boride ceramic microspheres obtained in Example 1.

[0048] Figure 2 This is a SEM image of the high-entropy boride ceramic microspheres obtained in Example 1.

[0049] Figure 3 This is a SEM image of the high-entropy boride ceramic microspheres obtained in Example 2.

[0050] Figure 4 This is a SEM image of the high-entropy boride ceramic microspheres obtained in Comparative Example 1.

[0051] Figure 5 This is a SEM image of the high-entropy boride ceramic microspheres obtained in Comparative Example 2.

[0052] Figure 6 This is a SEM image of the high-entropy boride ceramic microspheres obtained in Comparative Example 3.

[0053] Figure 7 This is a SEM image of the high-entropy boride ceramic microspheres obtained in Comparative Example 4. Detailed Implementation

[0054] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0055] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0056] Example 1

[0057] In this embodiment, the high-entropy boride precursor is prepared using the following method:

[0058] (1) Obtaining metal alkoxides: Select metal alkoxides Ti(OPr)4, Zr(OPr)4, Hf(OPr)4Nb(OCH2CH2OCH2CH3)5 and Ta(OCH2CH3)5.

[0059] Ti(OPr)4 and Zr(OPr)4 were purchased directly, while Hf(OPr)4Nb(OCH2CH2OCH2CH3)5 and Ta(OCH2CH3)5 were prepared using the following method:

[0060] Hf(OPr)4 and Nb(OCH2CH2OCH2CH3)5 were prepared by dispersing metal salts HfCl4 and NbCl5 in n-heptane, respectively, and then adding monohydric alcohols n-propanol and ethylene glycol ethyl ether dropwise at -10°C, followed by the addition of triethylamine. After the addition was complete, the mixture was heated under reflux for 1 hour and filtered to obtain metal alkoxide solutions. The molar ratio of HfCl4, n-propanol, and triethylamine was 1:4:4, and the molar ratio of NbCl5, n-propanol, and triethylamine was 1:5:6.

[0061] Ta(OCH2CH3)5 is prepared by dispersing the metal salt TaCl5 in ethylene glycol dimethyl ether, adding monohydric alcohol ethanol dropwise at -5°C, followed by triethylamine, heating under reflux for 1 hour after the addition is complete, and filtering to obtain a metal alkoxide solution; wherein the molar ratio of TaCl5, ethanol and triethylamine is 1:5:5.

[0062] (2) Preparation of metal alkoxide complexes: Acetylacetone was added dropwise to metal alkoxides Ti(OPr)4, Zr(OPr)4, Hf(OPr)4, Nb(OCH2CH2OCH2CH3)5 and Ta(OCH2CH3)5 at 40℃, and stirring was continued for 0.1 h after the addition was completed; the molar ratios of metal alkoxides Ti(OPr)4, Zr(OPr)4, Hf(OPr)4, Nb(OCH2CH2OCH2CH3)5, Ta(OCH2CH3)5 and acetylacetone were 1:0.48, 1:0.8, 1:1, 1:2 and 1:2, respectively;

[0063] (3) Co-hydrolysis: The metal alkoxide complex obtained in step (2) is mixed evenly according to the same metal molar ratio. At room temperature, a mixed solution of water and n-propanol is slowly added dropwise to the system, wherein the molar ratio of water to total metal is 1.5:1 and the mass ratio of n-propanol to water is 4:1. After the addition is complete, the mixture is refluxed for 5 hours to obtain a metal alkoxide copolymer solution.

[0064] (4) Preparation of boron carbon source: Boric acid and sorbitol are mixed evenly in acetic acid and then reacted at 60°C for 2 hours to obtain boron carbon source solution; the molar ratio of boric acid, sorbitol and acetic acid is 1:0.5:1.

[0065] (5) Preparation of precursor: Keep the temperature of the boron carbon source solution obtained in step (4) at 45°C, add the metal alkoxide copolymer solution obtained in step (3) to it, and then raise the temperature to 80°C for the first heating reaction. After the reaction is carried out for 1 hour until the system gels, raise the temperature to 120°C for the second heating reaction. The reaction time is 5 hours. Then the obtained gel is dried in a vacuum oven at 120°C for 4 hours. After cooling, the high-entropy boride precursor is obtained. The ratio of the total amount of metal in the metal alkoxide copolymer to the amount of boron in the boron carbon source is 1:2.5.

[0066] This embodiment uses the following method to prepare high-entropy boride ceramic microspheres:

[0067] (1) Preparation of boride powder: The above high-entropy boride precursor was placed in a graphite furnace and pyrolyzed at 1600℃ for 2 hours under vacuum. It was then ball-milled for 6 hours at a ball-to-material ratio of 5:1 and a ball mill speed of 300 rpm to obtain boride powder.

[0068] (2) Slurry preparation: Under stirring, deionized water, polyvinyl alcohol 1399, polyethylene glycol 600 and hydrochloric acid were added to the ball mill jar in sequence and stirred for 30 min. Then, n-butanol was added under stirring, followed by the boride powder obtained in step (1). Stirring was continued for 20 min, and finally, the ball milling beads were added and ball milling was performed to prepare a uniform and stable slurry. The mass percentage of the boride powder was 55 wt%, the mass percentage of polyvinyl alcohol 1399 was 0.8 wt%, the mass percentage of polyethylene glycol 600 was 1 wt%, the mass percentage of hydrochloric acid was 0.1 wt%, and the mass percentage of n-butanol was 0.1 wt%. The ball milling ratio was 5:1, and the ball milling was performed for 6 h at a speed of 300 rpm.

[0069] (3) Spray granulation: Spray granulation is performed on the slurry obtained in step (2) according to the following parameters: inlet air temperature 160℃, outlet air temperature 110℃, feed peristaltic pump speed 45rpm, atomizing disc frequency 180Hz; the material collection method is three-point collection, the three-point collection points include the bottom of the drying tower, the first-stage cyclone collection and the dust collector bag collection, and the target ceramic ball material is obtained by the bottom of the drying tower collection.

[0070] (4) Solid solution reaction: The small balls obtained in step (3) are placed in a graphite furnace and kept at 1900℃ under vacuum for 2 hours to carry out a high-temperature solid solution reaction. After cooling, high-entropy boride ceramic small balls are obtained.

[0071] Figure 1 The image shows the XRD pattern of the ceramic microspheres obtained in this embodiment. The XRD pattern shows only one set of diffraction peaks, indicating that all metal atoms are completely dissolved in a single crystal lattice, and the system does not contain impurity peaks of metal oxides, metal carbides, or boron carbide.

[0072] Figure 2 The image shows an SEM image of the microspheres obtained in this embodiment. It can be seen that the obtained ceramic microspheres are spherical with a diameter ranging from 30 to 70 μm.

[0073] The metal element content in the ceramic microspheres was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The results are as follows: Ti - 6.6%, Zr - 12.8%, Hf - 25.3%, Nb - 12.9%, Ta - 25.3%, B - 15.2%, which can be converted to the empirical formula (Ti1Zr...). 1.01 Hf 1.02 Nb 1.01 Ta 1.01 B 10.16 As can be seen, the content of metal and boron elements is close to the theoretical value.

[0074] The oxygen and carbon contents in the ceramic microspheres were measured to be 0.4 wt% and 0.8 wt% respectively using an oxygen-nitrogen analyzer and a carbon-sulfur analyzer, indicating that the ceramic microspheres prepared by this method have low impurity oxygen and impurity carbon contents.

[0075] Example 2

[0076] In this embodiment, the high-entropy boride precursor is prepared using the following method:

[0077] (1) Obtaining metal alkoxides: Select metal alkoxides Ti(OPr)4, Zr(Oi-Pr)4, Hf(Oi-Pr)4, Nb(OPr)5 and Mo(OCH2CH2OCH3)5. Among them, Nb(OPr)5, Hf(Oi-Pr)4 and Mo(OCH2CH2OCH3)5 are obtained by dispersing metal salts NbCl5, HfCl4 and MoCl5 in ethylene glycol dimethyl ether, xylene and n-hexane respectively. Under 0℃ conditions, monohydric alcohols n-propanol, isopropanol and ethylene glycol dimethyl ether are added dropwise respectively, followed by triethylamine. After the addition is completed, the mixture is heated under reflux for 2 hours and filtered to obtain metal alkoxide solutions. The molar ratios of metal salts, monohydric alcohols and triethylamine are 1:8:6, 1:4:4 and 1:10:6 respectively.

[0078] (2) Preparation of metal alkoxide complexes: At room temperature, ethyl acetoacetate was added dropwise to metal alkoxides Ti(OPr)4, Zr(Oi-Pr)4, Hf(Oi-Pr)4, Nb(OPr)5 and Mo(OCH2CH2OCH3)5 respectively, and stirring was continued for 0.5 h after the addition was completed; the molar ratios of metal alkoxides Ti(OPr)4, Zr(Oi-Pr)4, Hf(Oi-Pr)4, Nb(OPr)5 and Mo(OCH2CH2OCH3)5 to ethyl acetoacetate were 1:1.6, 1:0.6, 1:1, 1:0.8 and 1:2 respectively;

[0079] (3) Co-hydrolysis: The metal alkoxide complex obtained in step (2) is mixed evenly according to the same metal molar ratio. At room temperature, a mixed solution of water and ethylene glycol ethyl ether is slowly added dropwise to the system, wherein the molar ratio of water to total metal is 0.9:1 and the mass ratio of n-propanol to water is 5:1. After the addition is complete, the mixture is refluxed for 5 hours to obtain a metal alkoxide copolymer solution.

[0080] (4) Preparation of precursor: Add glyceryl borate to the metal alkoxide copolymer solution obtained in step (3), heat to 60°C, react for 5 h to obtain a homogeneous and transparent solution, then heat to 100°C and react for 4 h, followed by atmospheric distillation. Mix the obtained product with allylphenol aldehyde in ethylene glycol methyl ether, heat to 80°C, react for 4 h, then cool to obtain a boride high-entropy ceramic precursor; wherein, the ratio of the total moles of metal in the metal alkoxide copolymer to the moles of boron in the boron-containing compound to the mass of allylphenol aldehyde is 1 mol: 8 mol: 20 g; the mass ratio of allylphenol aldehyde to ethylene glycol methyl ether is 1: 5.

[0081] This embodiment uses the following method to prepare high-entropy boride ceramic microspheres:

[0082] (1) Preparation of boride powder: The above high-entropy boride precursor was placed in a graphite furnace and pyrolyzed at 1600℃ for 1h under vacuum. The precursor was ball-milled for 10h at a ball-to-material ratio of 10:1 and the ball mill speed was 350rpm to obtain boride powder.

[0083] (2) Slurry preparation: Under stirring, deionized water, gum arabic, polyethylene glycol 1000 and glacial acetic acid were added to the ball mill jar in sequence and stirred for 20 min. Then, n-butanol was added under stirring, followed by the boride powder obtained in step (1). Stirring was continued for 30 min, and finally, the ball milling beads were added and ball milling was performed to prepare a uniform and stable slurry. The mass percentage of boride powder was 45 wt%, gum arabic was 0.5 wt%, polyethylene glycol 1000 was 0.6 wt%, glacial acetic acid was 0.1 wt%, and n-butanol was 0.1 wt%. The ball milling ratio was 5:1, and the ball milling was performed for 6 h at a speed of 300 rpm.

[0084] (3) Spray granulation: Spray granulation is performed on the slurry obtained in step (2) according to the following parameters: inlet air temperature 160℃, outlet air temperature 120℃, feed peristaltic pump speed 10rpm, atomizing disc frequency 150Hz; the material collection method is three-point collection, the three-point collection points include the bottom of the drying tower, the first-stage cyclone collection and the dust collector bag collection, and the target ceramic ball material is obtained by the bottom of the drying tower collection.

[0085] (4) Solid solution reaction: The small balls obtained in step (3) are placed in a graphite furnace and kept at 2000℃ under vacuum for 2 hours to carry out a high-temperature solid solution reaction. After cooling, high-entropy boride ceramic small balls are obtained.

[0086] Figure 3 The image shows an SEM image of the microspheres obtained in this embodiment. It can be seen that the obtained ceramic microspheres are spherical with a diameter ranging from 30 to 80 μm.

[0087] The metal element content in the ceramic microspheres was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The results are as follows: Ti - 7.5%, Zr - 14.4%, Hf - 28.6%, Nb - 14.8%, Mo - 15.2%, B - 17.3%, which can be converted to the empirical formula (Ti 1 Zr 1 Hf). 1.02 Nb 1.01 Mo 1.01 B 10.17 As can be seen, the content of metal and boron elements is close to the theoretical value.

[0088] The oxygen and carbon contents in the ceramic microspheres were measured to be 0.8 wt% and 0.7 wt% respectively using an oxygen-nitrogen analyzer and a carbon-sulfur analyzer, indicating that the ceramic microspheres prepared by this method have low impurity oxygen and impurity carbon contents.

[0089] The particle image analyzer test results show that the sphericity of the small ball is 96%.

[0090] Comparative Example 1

[0091] The preparation method of high-entropy boride ceramic microspheres in this comparative example differs from that in Example 1 only in that: hydrochloric acid, a pH adjuster, was not added during the preparation of the slurry in step (2).

[0092] The remaining conditions are the same as in Example 1.

[0093] Figure 4 The image shows the SEM image of the ceramic microspheres obtained in this comparative example. It can be seen from the image that the ceramic microspheres produced by spray granulation from slurry without the addition of pH adjuster have poor sphericity and produce a large number of apple-shaped microspheres.

[0094] Comparative Example 2

[0095] The preparation method of high-entropy boride ceramic microspheres in this comparative example differs from that in Example 1 only in that polyethylene glycol, a dispersant, was not added during the preparation of the slurry in step (2).

[0096] The rest is the same as in Example 1.

[0097] Figure 5 The image shows the SEM image of the ceramic microspheres prepared in this comparative example. It can be seen from the image that the ceramic microspheres prepared by spray granulation from slurry without the addition of dispersant have irregular shapes and poor sphericity.

[0098] Comparative Example 3

[0099] The preparation method of high-entropy boride ceramic microspheres in this comparative example differs from that in Example 1 only in that: n-butanol, the defoamer, was not added during the preparation of the slurry in step (2).

[0100] The remaining conditions are the same as in Example 1.

[0101] Figure 6 The image shows the SEM image of the ceramic microspheres prepared in this comparative example. It can be seen from the image that the ceramic microspheres prepared by spray granulation from slurry without the addition of defoamer are irregular in shape and almost cannot be spherical.

[0102] Comparative Example 4

[0103] The preparation method of high-entropy boride ceramic microspheres in this comparative example differs from that in Example 1 only in that the material collection method involves two-point collection, which includes a primary cyclone collection connected by a connecting pipe and a dust collector bag collection, wherein the material obtained by the primary cyclone collection is the target ceramic microsphere material.

[0104] The remaining conditions are the same as in Example 1.

[0105] Figure 7 The image shows the SEM image of the ceramic microspheres prepared in this comparative example. It can be seen from the image that the microspheres obtained by the two-point material collection method are broken and the surface of the microspheres is not smooth, with a large number of small particles adhering to the outer wall of the ceramic microspheres.

[0106] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of producing a ceramic ball, characterized by, The ceramic balls are prepared by spray granulation of the following slurry and high-temperature solid solution reaction of the spray granulated ceramic balls; The slurry contains 45wt% to 55wt% of boride powder by mass. The adhesive in the slurry has a mass percentage of 0.5wt% to 0.8wt%. The mass percentage of dispersant in the slurry is 0.6wt%~1.0wt%; The pH adjuster in the slurry has a mass percentage of 0.1 wt% to 0.6 wt%. The defoamer in the slurry has a mass percentage of 0.1wt% to 0.6wt%. The slurry also includes a solvent, which is water; The sum of the weight percentages of all components in the slurry is 100%. The boride powder is obtained by high-entropy boride precursor through high-temperature pyrolysis followed by ball milling; the high-temperature pyrolysis temperature is 1500-1650℃, and the high-temperature pyrolysis time is 1-6h. The granulation parameters for the spray granulation method are as follows: inlet air temperature is 160℃~180℃; outlet air temperature is 110℃~120℃; feed peristaltic pump speed is 30~45rpm; atomizing disc frequency is 150Hz~200Hz. The material collection method of the spray granulation method is three-point collection, which includes material collection at the bottom of the drying tower, material collection by the primary cyclone, and material collection by the dust collector bag. The ceramic balls are obtained by material collection at the bottom of the drying tower. The high-temperature solution reaction temperature is 1900℃~2000℃; the high-temperature solution reaction time is 1-2 hours; the adhesive is selected from one or a mixture of several of gum arabic and polyvinyl alcohol; The dispersant is polyethylene glycol; The pH adjuster is selected from one or a mixture of several of hydrochloric acid and glacial acetic acid; The defoamer is n-butanol.

2. The method of claim 1, wherein the ceramic balls are prepared by the steps of: The sphericity of the ceramic sphere is not less than 90%; ​ And / or, the diameter of the ceramic spheres ranges from 30 to 80 μm.

3. The method of claim 2, wherein the ceramic balls are prepared by the steps of: The diameter of the ceramic spheres ranges from 30 to 70 μm. ​ 4. The method of producing ceramic balls according to any one of claims 1 to 3, wherein The ceramic ball contains boron and also includes at least four of the following metallic elements: Ti, Zr, Hf, V, Nb, Ta, Mo, and W.

5. The method of claim 4, wherein the ceramic balls are prepared by the steps of: In the ceramic sphere, the number of moles of each metal element may be the same or different, and each element independently accounts for 5 to 35% of the total number of moles of metal in the ceramic sphere. ​ 6. The method of claim 5, wherein the ceramic balls are prepared by the steps of: The ratio of the total molar amount of the metallic elements to the molar amount of boron is 1:2.0~2.2; ​ And / or, the oxygen and carbon content in the ceramic spheres is both less than 1 wt%.

7. The production method according to claim 6, wherein The preparation method includes the following steps: (1) Preparation of boride powder: The high-entropy boride precursor was pyrolyzed at 1500-1600℃ and then ball-milled to obtain boride powder; (2) Slurry preparation: Mix solvent, binder, dispersant and pH adjuster, add defoamer while stirring, then add boride powder obtained in step (1), ball mill to prepare slurry; (3) Spray granulation: The slurry obtained in step (2) is spray granulated to obtain boride ceramic balls; (4) Solid solution reaction: The ceramic balls obtained in step (3) are subjected to a high-temperature solid solution reaction to obtain high-entropy boride ceramic balls.

8. A coating comprising ceramic spheres prepared by any one of claims 1-7 or ceramic spheres prepared by any one of claims 1-7.

9. The use of a high-entropy boride ceramic ball prepared by the preparation method according to any one of claims 1-7 and / or the coating according to claim 8 in the fields of ultra-high temperature components, high wear-resistant components, components resistant to molten metal corrosion, and neutron radiation protection devices.

10. A component having a surface provided with a high-entropy boride ceramic ball prepared by the preparation method according to any one of claims 1-7 and / or a coating according to claim 8.

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