CN115196970B - Preparation method of high-fluidity AlON spherical powder - Google Patents
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Abstract
The invention provides a preparation method of high-fluidity AlON spherical powder, which comprises the following steps: (1) Dissolving a dispersing agent in an ethanol-water solution, wherein the ethanol content in the ethanol-water solution is 3-5% by volume, adding a carbon source, ball milling, adding an aluminum source, and ball milling to obtain a uniformly mixed raw material powder solution; (2) Adding a binder, ball milling to obtain slurry, and adjusting the solid content of the slurry to be 35-50%; (3) spray granulating the slurry; (4) Collecting the materialized pellets, preserving the heat for 1h at 750-800 ℃, then obtaining pure phase AlON spherical powder by a one-step sintering method, cooling, taking out, and then heating to 700 ℃ in air for roasting for a period of time to obtain the high-fluidity AlON spherical powder. The AlON spherical powder prepared by the method has the advantages of good fluidity, narrow particle size distribution, high balling rate, small spherical particle size and difficult agglomeration in the sintering process.
Description
Technical Field
The invention belongs to the technical field of preparation of raw material powder of transparent ceramics, and particularly relates to a preparation method of high-fluidity AlON spherical powder.
Background
Aluminum oxynitride (gamma-AlON) can obtain transmittance of more than 80% in a wide band region of 0.2-5 μm due to an isotropic crystal structure, shows excellent optical performance, and is an important transparent ceramic material. Meanwhile, the nitrogen atoms are introduced to ensure that the aluminum oxynitride material shows excellent physical and chemical properties, has excellent high temperature resistance, thermal vibration stability, erosion resistance and processability, can replace sapphire to be an important material for a protection window due to light weight, and has been widely applied to various fields such as civil use, military industry and the like.
In order to prepare AlON transparent ceramics with good compactness and high transparency, scientific researchers at home and abroad have carried out a great deal of researches on the preparation method, and the current research results show that: firstly, preparing AlON powder with excellent performance is a precondition for preparing AlON transparent ceramics with high optical performance.
The most common methods for preparing AlON powder are solid phase reaction and alumina carbothermic reduction. However, the existing AlON powder preparation method still has the following defects: firstly, the solid phase reaction method requires that the aluminum nitride powder raw material has the characteristics of ultra-fine, high purity and easy dispersion, which results in higher production cost of AlON powder and difficult obtainment of raw material; secondly, although the carbothermic reduction method does not need high-purity AlN powder, the carbothermic reduction method has the defects of long reaction time, larger influence by raw material proportion and difficult synthesis of pure-phase gamma-AlON powder, so that the production efficiency of the AlON powder is lower, and the difference of raw material powder in different batches is larger.
Therefore, the existing AlON powder preparation method generally has the problems of higher reaction temperature, long heat preservation time, larger powder particle size, easiness in occurrence of uneven sintering, difficulty in crushing or long crushing time and the like.
Research shows that the application performance of the aluminum oxynitride product in many fields has close relation with the morphology and the size of raw material powder particles. Among powder particles with different shapes, spherical particles have regular morphology, smaller specific surface area, larger bulk density and better flow property, so that the application performance of the transparent ceramic product can be greatly improved. Therefore, the preparation research of the ceramic spherical raw material powder is further developed at home and abroad, and a certain result is obtained.
The existing spherical powder main preparation technology comprises an atomization method and a spheroidization method, wherein the atomization method is the most widely applied, and comprises a gas atomization method, a centrifugal atomization method and an ultrasonic atomization method. However, research shows that various operating factors (such as the rotating speed of a spray head, the inlet temperature of drying air, the outlet temperature of waste gas and the like, and the properties of slurry such as the solid phase content and viscosity of the slurry) can have a great influence on the morphology and particle size distribution of the powder in the process of granulating by using centrifugal spray drying.
A great deal of literature indicates that the preparation of spherical powder with narrow particle size distribution range, high sphericity, small spherical particle size and good particle flowability is a great difficulty.
Patent document CN 102060519A discloses a method for preparing rare earth doped yttrium aluminum garnet transparent ceramic by spray granulation modified powder, which is to prepare rare earth doped Re: YAG powder by a coprecipitation method, and then modify the powder by a spray granulation process, but the method has poor formability of spherical powder, uneven particle size distribution, and the transmittance of the finally sintered transparent ceramic is low and mostly only reaches 69-75%.
Patent document CN 103785843B discloses a method for preparing ultrafine titanium carbonitride-based cermet spherical agglomerated powder, which adopts a high-speed centrifugal spray granulation dryer to carry out spray granulation treatment on ultrafine titanium carbonitride-based cermet powder slurry, however, because the ceramic powder slurry has poor fluidity, although the spherical shape is better, the uniformity of the powder is poorer, and the particle size distribution of the spherical powder is wider, which is between 20 and 200 mu m.
Patent document CN 104355609A discloses a spray granulation preparation method of YAG-based transparent ceramic powder, which comprises the steps of adding a sintering aid, a dispersing agent and a solvent into raw material powder to prepare slurry, ball-milling and mixing the slurry on a planetary ball mill, adding a binder, and continuing ball-milling and mixing to obtain slurry for spray granulation; and then, spraying and granulating the slurry by using a centrifugal spray dryer, and sieving the obtained granulated powder to obtain the YAG-based transparent ceramic powder, wherein the spherical powder with good sphericity and fluidity can be prepared by the method, but the particle size distribution of the spherical powder is wider and is between 10 and 90 mu m.
Patent document CN 104591240a discloses a preparation technology of spherical alumina powder, which takes aluminum nitrate and ammonia water as raw materials, by controlling reactant concentration, ammonia water is used for dropwise adding aluminum nitrate solution at a certain temperature, when the pH value of a reaction system reaches a specified value, ammonia water is stopped being dropwise added, then spray drying is carried out on the reaction solution by using nozzles with different sizes, so as to obtain spherical alumina precursor, and the precursor is calcined for 1-3 hours at 450-600 ℃ to obtain gamma-type spherical alumina powder with different average particle diameters. Although the obtained spherical particles have smaller size and narrower particle size distribution, the method needs to strictly control the concentration and pH value of reactants in preparation of reaction liquid, has more complex operation, and the obtained spherical particles are easy to agglomerate, and the spherical powder has more serious bonding phenomenon due to smaller particle size.
Patent document CN 108002354A discloses a preparation method of particle-diameter-controllable spheroidal aluminum nitride powder, which comprises the steps of uniformly wet-grinding aluminum oxide, carbon powder, a calcium fluoride additive and aluminum nitride seed crystal in a ball mill according to a certain proportion, drying, placing into a sintering furnace, reacting for 1-4 h at 1550-1800 ℃ under the protection of nitrogen atmosphere, and removing carbon in a muffle furnace to obtain the spheroidal aluminum nitride powder. Although the method can lead the particle size of the spheroid particles to be smaller and the particle size distribution to be narrower and can be controlled between 4 and 30 mu m, the method can not obtain the powder particles with better sphericity.
The above patents show that in the method for preparing ceramic spherical powder by adopting an atomization method, it is still difficult to obtain spherical powder with narrow particle size distribution, high sphericity, small spherical particle size and good particle flowability. In the preparation process of AlON powder, the AlON transparent ceramic has higher requirements on the particle size and distribution uniformity of raw materials, and meanwhile, due to the fact that Al is sintered at high temperature 2 O 3 Agglomeration is extremely easy, and it becomes more difficult to obtain AlON spherical powder with high performance.
Therefore, how to prepare AlON spherical powder which has narrow particle size distribution, high sphericity, small spherical particle size, good particle mobility and difficult agglomeration by using an atomization method becomes a technical problem to be solved.
Disclosure of Invention
The invention aims to solve the technical problems, and provides a preparation method of high-fluidity AlON spherical powder. The technical purpose of the invention is that: firstly, the method for preparing AlON spherical powder solves the problems that the existing preparation method of spherical powder does not relate to the preparation of AlON spherical powder, and provides a method capable of well preparing AlON spherical powder; secondly, the problems of wide particle size distribution, low balling rate, large spherical particle size, poor particle mobility and easy agglomeration existing in the existing preparation process of the spherical powder are solved.
In order to achieve the technical purpose, the invention adopts the following technical scheme:
the preparation method of the high-fluidity AlON spherical powder comprises the following steps:
(1) Dissolving a dispersing agent in an ethanol-water solution, wherein the ethanol content in the ethanol-water solution is 3-5% by volume, adding a carbon source into the ethanol-water solution after uniform mixing, ball milling for 1-1.5 h, adding an aluminum source, and ball milling for 2-4 h to obtain a uniformly mixed raw material powder solution;
(2) Adding a binder into the raw material powder solution, ball milling for 3.5-4 hours, enabling the binder to fully act with the surface of the raw material powder to obtain slurry, and adjusting the solid content of the slurry to be 35-50%;
(3) And (3) carrying out spray granulation on the slurry obtained in the step (2) by adopting a centrifugal spray dryer, wherein parameters of the centrifugal spray dryer are controlled as follows: after the temperature of the air outlet reaches 107 ℃, starting a peristaltic pump, supplying water, adjusting the materialization frequency and materialization temperature to be in the range of 105-109 ℃, and then conveying the slurry to spray granulation;
(4) Collecting the pellets after materialization in the step (3), and placing the pellets in N 2 And (3) preserving heat for 1h at 750-800 ℃ in the atmosphere to enable the organic additive to be fully carbonized, obtaining pure phase AlON spherical powder through a one-step sintering method, reducing the temperature to normal temperature, heating to 700 ℃ in the air, roasting for a period of time, and removing residual impurities to obtain the high-fluidity AlON spherical powder.
The preparation method provided by the invention is to find a method which can ensure the high stability of slurry and can obtain high-fluidity AlON spherical powder by using a centrifugal spray method by taking a carbon source and an aluminum source as raw materials and adopting a carbothermic reduction method in combination with a spray granulation technology. The method has the characteristics of easily available raw materials, simple structure, low cost, high acquisition efficiency and the like, and the obtained spherical powder can be used for forming ceramic blanks and also can be used for preparing approximate spheres with the particle size of microns.
The inventors have made extensive studies on the preparation process of AlON spherical powder, and have found that the obtained spherical powder is poor in effect, nonuniform in particle size distribution and poor in sphericity, and the analysis is due to poor stability of the obtained slurry, and the addition of a dispersing agent easily generates bubbles in the ball milling process, which seriously affects the sphericity of the powder in the spray granulation process and the uniformity of particle size. On the other hand, the parameters in the spray drying granulation process have a large influence on the sphericity, and the effect of the prepared spherical powder is easily influenced.
Finally, the inventor surprisingly found that the problem that the powder solution is easy to generate bubbles can be well solved by adding the dispersing agent into the aqueous solution containing 3-5% of ethanol and then adding the carbon source and the aluminum source for ball milling respectively; meanwhile, after the raw material powder solution is prepared, the binder is added into the raw material powder solution for ball milling, so that the stability of the slurry can be well ensured, the solid content of the slurry can be kept at a higher level, and meanwhile, the raw material powder solution has excellent colloid protection capability, and further, the balling rate of the spherical powder and the uniformity of particle size distribution are improved.
In addition, the inventor finds that each parameter of the centrifugal atomizer needs to be precisely controlled, and when each parameter has poor control effect, the obtained powder balling rate is low. Finally, the inventor precisely controls various parameters of the centrifugal atomizer to obtain a method capable of well preparing high-fluidity spherical powder, and the pellets obtained by spraying and material making are sintered in one step to obtain pure-phase AlON spherical powder, and the spherical powder has the advantages of excellent fluidity, narrow particle size distribution, high sphericity rate, small spherical particle size and difficult agglomeration in the sintering process.
The high-fluidity AlON spherical powder prepared by the method has good compression molding and sintering characteristics on one hand, and can prepare high-quality AlON ceramic products, wherein the transmittance of the AlON ceramic products can reach 84%. On the other hand, the spherical powder can regulate and control the size distribution of particles by adjusting the size distribution, so that the aluminum oxynitride can be applied to special ceramics such as catalyst carriers, packaging materials, 3D printing and the like and high and new technical fields, and has wide application prospects.
Further, in the step (1), the dispersing agent is ammonium polyacrylate, and the adding amount of the dispersing agent is 3-5% of the total weight of the ethanol-water solution.
Further, the carbon source in the step (1) comprises sucrose (C 12 H 22 O 11 ) Or glucose (C) 12 H 22 O 11 ) The addition amount of any one of the above materials is 3 percent of the total weight of the raw material powder solution; the aluminum source is gamma-Al 2 O 3 The addition amount of the additive is 47 percent of the total weight of the raw material powder solution.
Further, the number of revolutions of the ball mill in the step (1) was 120rpm.
Further, in the step (2), the binder is hydroxyethyl cellulose (HEC), and the addition amount of the binder accounts for 1% of the total weight of the raw material powder solution.
Further, the operation of the one-step sintering method in the step (4) is as follows: the pellets are placed in a boron nitride crucible, and after the temperature is raised to 1750 ℃, the temperature is kept for 1h, and the heating rate is 10 ℃/min.
Further, in the step (4), the cooling rate to the normal temperature is 10 ℃/min, and then the temperature is raised to 700 ℃ in the air and then the baking is performed for 1h.
The beneficial effects of the invention are as follows:
(1) The invention provides a method for preparing AlON spherical powder in batches, which has the characteristics of easily available raw materials, simple structure, low cost, high acquisition efficiency and the like;
(2) The preparation method of the AlON spherical powder has the characteristics of narrow particle size distribution, high sphericity, small spherical particle size, good particle mobility and difficult agglomeration;
(3) According to the preparation method of the AlON spherical powder, the median particle size of AlON pellets can be reduced to 10 mu m, the specific surface area of the powder is increased while the high fluidity of the spherical powder is ensured, the activity of the powder is enhanced, and the transmittance of the prepared AlON transparent ceramic reaches 84%;
(4) The AlON pellets prepared by the method have good sphericity and a certain pore structure on the surface of the pellets, which is beneficial to N 2 Has a certain promoting effect on improving sintering efficiency.
Drawings
FIG. 1 is a surface morphology of AlON pellet powder obtained in example 1 of the present invention;
FIG. 2 is an enlarged view of the surface morphology of AlON pellet powder obtained in example 1 of the present invention;
FIG. 3 is a graph showing the particle size distribution of AlON pellet powder obtained in example 1 of the present invention;
FIG. 4 is a surface morphology of AlON pellet powder obtained in comparative example 3;
FIG. 5 is a surface morphology of AlON pellet powder obtained in comparative example 4;
FIG. 6 is a surface morphology of AlON pellet powder obtained in comparative example 5;
FIG. 7 is a surface morphology of AlON pellet powder obtained in comparative example 6;
FIG. 8 is a graph showing the viscosity change of the AlON slurry obtained in comparative example 6.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be specifically described with reference to the following examples, which are provided for explaining and illustrating the present invention only and are not intended to limit the present invention. Some non-essential modifications and adaptations of the invention according to the foregoing summary will still fall within the scope of the invention.
Example 1
The preparation method of the AlON spherical powder comprises the following steps:
(one) preparing a slurry for spraying
Weighing deionized water according to the required powder with 40% (wt) solid content, adding 3% (vol) ethanol, ball milling for 10min, weighing 3% (wt) ammonium polyacrylate (C3H 7NO 2), adding into the above solution, ball milling for 10min, and adding 3% (wt) glucose (C) 6 H 12 O 6 ) Ball milling for 1h as a carbon source, mixing uniformly, adding 47% (wt) gamma-Al 2 O 3 Ball milling for 2h to obtain a raw material powder solution; adding 1% (wt) hydroxyethyl cellulose (HEC) into the raw material powder solution, and ball milling for 1h to enable the binder to fully act with the surface of the raw material powder to obtain slurry, wherein the solid content of the slurry is 40% (wt);
(II) granulating with a sprayer
Opening an induced draft fan, ensuring normal circulation of cooling water, sequentially opening the induced draft fan, a stirring motor, pulse dust removal, electric heating (preset temperature is determined according to the needed materialization temperature), and an atomizer, after the air outlet temperature (materialization temperature is the same as materialization temperature) reaches 107 ℃ which can be used for materialization, starting a peristaltic pump, firstly supplying water, adjusting materialization frequency and materialization temperature according to the sequence from low frequency (50 HZ) to high frequency (300 HZ), and the like, stabilizing (105-107 ℃), conveying the slurry (the rotating speed of the peristaltic machine: 25 rpm), after the slurry is conveyed, firstly conveying water for a while (2 min), then closing heating, and after the materialization bin temperature is reduced to room temperature, closing the atomizer, collecting raw material pellets after materialization, and screening the pellets by 300 meshes;
(III) sintering the powder
Placing the materialized pellets into a boron nitride crucible in flowing N 2 Preserving heat for 1h at a certain temperature (780 ℃) in the atmosphere to fully carbonize the organic additive, then directly heating to 1750 ℃ at a heating rate of 10 ℃/min, and preserving heat for 1h to obtain AlON phase spherical powder; finally, taking out the spherical powder after cooling to normal temperature, then roasting for 1h in the air at the temperature of 700 ℃, and removing residual impurities to obtain pure-phase spherical AlON powder.
Example 2
The preparation method of the AlON spherical powder comprises the following steps:
(one) preparing a slurry for spraying
Measuring deionized water according to the required powder with 35% (wt) solid content, adding 4% (vol) ethanol, ball milling for 12min, weighing 4% (wt) ammonium polyacrylate, adding into the above solution, ball milling for 8min, and adding 3% (wt) glucose (C) 6 H 12 O 6 ) Ball milling for 1h as a carbon source, mixing uniformly, adding 47% (wt) gamma-Al 2 O 3 Ball milling for 3h to obtain a raw material powder solution; adding 1% (wt) hydroxyethyl cellulose (HEC) into the raw material powder solution, ball milling for 1h to enable the binder to fully act with the surface of the raw material powder to obtain slurry, wherein the solid content of the slurry isThe amount was 35% (wt);
(II) granulating with a sprayer
Opening an induced draft fan, ensuring normal circulation of cooling water, sequentially opening the induced draft fan, a stirring motor, pulse dust removal, electric heating (preset temperature is determined according to the required materialization temperature), and an atomizer, starting a peristaltic pump after the air outlet temperature (materialization disc temperature) reaches the available materialization temperature (107 ℃), firstly supplying water, sequentially adjusting materialization frequency and materialization temperature according to low frequency to high frequency, stabilizing the materialization frequency and materialization temperature (stabilizing between 107 ℃ and 109 ℃), conveying the slurry, firstly conveying water for a while after the slurry is conveyed, then closing the heating, waiting for the materialization bin temperature to be reduced to room temperature, closing the atomizer, collecting materialized raw material pellets, and sieving the pellets by a 300-mesh sieve;
(III) sintering the powder
Placing the materialized pellets into a boron nitride crucible in flowing N 2 Preserving the temperature of the atmosphere at a certain lower temperature (780 ℃) for 1h to fully carbonize the organic additive, and then directly heating to 1750 ℃ at a heating rate of 10 ℃/min, and preserving the temperature for 1h to obtain AlON phase spherical powder; finally, taking out the spherical powder after cooling to normal temperature, then roasting for 1h in the air at the temperature of 700 ℃, and removing residual impurities to obtain pure-phase spherical AlON powder.
Example 3
The preparation method of the AlON spherical powder comprises the following steps:
(one) preparing a slurry for spraying
Weighing deionized water according to the required powder with 50% (wt) of solid content, adding 5% (vol) of ethanol, ball milling for 15min, weighing 5% (wt) of ammonium polyacrylate, adding into the solution, ball milling for 15min, adding 3% (wt) of carbon black as carbon source, ball milling for 1.5h, mixing uniformly, and adding 47% (wt) of gamma-Al 2 O 3 Ball milling the alumina for 4 hours to obtain a raw material powder solution; adding 1% (wt) hydroxyethyl cellulose (HEC) into the raw material powder solution, and ball milling for 1h to enable the binder to fully act with the surface of the raw material powder to obtain slurry, wherein the solid content of the slurry is 50% (wt);
(II) granulating with a sprayer
Opening an induced draft fan, ensuring normal circulation of cooling water, sequentially opening the induced draft fan, a stirring motor, pulse dust removal, electric heating (preset temperature is determined according to the required materialization temperature), and an atomizer, starting a peristaltic pump after the air outlet temperature (materialization disc temperature) reaches the available materialization temperature (107 ℃), firstly supplying water, sequentially adjusting materialization frequency and materialization temperature according to low frequency to high frequency, stabilizing the materialization frequency and materialization temperature, conveying the slurry (between 106 and 108 ℃), firstly conveying water for a while after the slurry is conveyed, then closing the heating, waiting for the materialization bin temperature to be reduced to room temperature, closing the atomizer, collecting materialized raw material pellets, and sieving the pellets by using a 300-mesh screen;
(III) sintering the powder
Placing the materialized pellets into a boron nitride crucible in flowing N 2 Preserving the temperature of the atmosphere at a certain lower temperature (800 ℃) for 1h to fully carbonize the organic additive, then directly heating to 1750 ℃ at a heating rate of 10 ℃/min, and preserving the temperature for 1h to obtain AlON spherical powder; finally, taking out the spherical powder after cooling to normal temperature, and then roasting for 1h in the air at the temperature of 700 ℃ to remove residual impurities, thus obtaining the pure phase AlON spherical powder.
Characterization example 1
Characterization of pure phase spherical AlON powder obtained in the above examples 1-3, taking example 1 as an example (the results of other examples are not greatly different), SEM appearance is shown in FIG. 1-2, particle size distribution is shown in FIG. 3, it can be seen that the spherical AlON powder prepared by the invention has high sphericity, narrow particle size distribution, small size (10 μm) of spherical particles, pores on the surface, and no agglomeration phenomenon of the pellets.
Comparative example 1
The preparation method of example 1 was followed, except that the dispersant was directly added to water without adding ethanol in the step (one), to prepare AlON spherical powder. In the experimental process, it is found that the dispersing agent is easy to generate bubbles when ball milling is performed in water due to the fact that ethanol is not added, a large amount of bubbles are generated in the raw material powder solution, and finally, the pellets obtained through spray granulation are poor in sphericity, low in sphericity rate and uneven in particle size distribution.
Comparative example 2
The preparation process according to example 1 is followed, except that the parameters of the spray granulation in step (two) are adjusted as follows: the materialization temperature is changed from 107 ℃ to 120 ℃, or the rotating speed of a peristaltic machine is changed from 25rpm to 50rpm, and the result shows that the prepared pellets have poor molding effect, low balling rate and wider particle size distribution.
Comparative example 3
The preparation method of example 1 was followed, except that the binder HEC in step (one) was replaced with PVA (polyvinyl alcohol) and the solid content of the slurry was raised to 50wt%, and the result of preparing AlON spherical powder was shown in fig. 4.
Since PVA has poor water solubility at normal temperature and requires long stirring, the binding ability is lowered, and thus the solid content is adjusted to 50% for preparation. However, even in the case of already high solids content, the product obtained by spray granulation still presents surface voids and irregular morphology of the bulk (see fig. 4), rather than regular spheres, which have a very low rate of spheronization.
Comparative example 4
The preparation method of example 1 was followed except that in the step (one), the solid content of the slurry was adjusted to 30wt%, pellets were prepared, and then high-temperature sintering was performed, the results of which are shown in fig. 5.
Under the high temperature environment, the solution is centrifuged, and the spherical particles formed gradually evaporate water molecules from inside to outside in the drying process. Due to the reduced solids content, a thin shell is formed by a large amount of water during the drying process, resulting in the void content of the spheres, which lead to cracking of the spheres during high temperature sintering (see fig. 5).
Comparative example 5
The preparation method according to example 1 is different in that no dispersant is added in step (one), resulting in cracking of the pellets, the addition of the dispersant can significantly reduce the viscosity and surface tension of the suspension, while the slurry viscosity and quality significantly affect the size of the particles and the variation of centrifugal shear force. Due to uneven dispersion of the raw materials, the carbon source is easily coated with alumina, resulting in uneven drying (see fig. 6).
Comparative example 6
The preparation method of example 1 was followed, except that the carbon source in step (one) was replaced with carbon black, and the results are shown in fig. 7 and 8. It can be seen that although the carbon black has a good spherical shape, the overall pellet size distribution is not uniform and the particle size is large (80 μm or more). This is because carbon black has poor water solubility, and when water is added, the viscosity of the slurry increases significantly, resulting in a decrease in shear force, and therefore it is difficult to centrifuge into spheres with smaller grains.
Claims (5)
1. The preparation method of the high-fluidity AlON spherical powder is characterized by comprising the following steps of:
(1) Dissolving a dispersing agent in an ethanol water solution, wherein the ethanol content in the ethanol water solution is 3-5% by volume, adding a carbon source into the ethanol water solution after uniform mixing, ball milling for 1-1.5 h, adding an aluminum source, and ball milling for 2-4 h to obtain a uniformly mixed raw material powder solution; the dispersing agent is ammonium polyacrylate, and the adding amount of the dispersing agent is 3-5% of the total weight of the ethanol aqueous solution; the carbon source comprises any one of sucrose or glucose, and the addition amount of the carbon source accounts for 3% of the total weight of the raw material powder solution; the aluminum source is gamma Al 2 O 3 The addition amount of the additive accounts for 47% of the total weight of the raw material powder solution;
(2) Adding a binder into the raw material powder solution, ball milling for 1-4 hours, enabling the binder to fully act with the surface of the raw material powder to obtain slurry, and adjusting the solid content of the slurry to be 35-50%;
(3) And (3) carrying out spray granulation on the slurry obtained in the step (2) by adopting a spray dryer, wherein parameters of the centrifugal spray dryer are controlled as follows: after the temperature of the air outlet reaches 107 ℃, starting a peristaltic pump, supplying water, adjusting the materialization frequency to enable the materialization temperature to be stabilized within the range of 105-109 ℃, and then conveying the slurry to carry out spray granulation;
(4) Collecting the pellets obtained in the step (3), preserving the temperature of the pellets at 750-800 ℃ for 1h in N2 atmosphere to enable the organic additive to be fully carbonized, obtaining pure-phase AlON spherical powder through a one-step sintering method, cooling, taking out, heating to 700 ℃ in air, roasting for a period of time, and removing residual impurities to obtain the high-fluidity AlON spherical powder.
2. The method according to claim 1, wherein the number of revolutions of the ball mill in step (1) is 120r/min.
3. The preparation method according to claim 1 or 2, wherein the binder in the step (2) is hydroxyethyl cellulose, and the addition amount of the binder is 1% of the total weight of the raw material powder solution.
4. The method according to claim 1 or 2, wherein the one-step sintering method in step (4) is operated as follows: the pellets are placed in a boron nitride crucible, and after the temperature is raised to 1750 ℃, the temperature is kept for 1h, and the heating rate is 10 ℃/min.
5. The method according to claim 1 or 2, wherein the cooling rate of the cooling in the step (4) is that the cooling rate is reduced to normal temperature at 10 ℃/min, and then the cooling rate is calcined in air at 700 ℃ for 1 hour.
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