Composite zirconia ceramic microbeads and method for preparing the same

Abstract

The application discloses a kind of composite zirconia ceramic microbeads and preparation method thereof, belong to zirconia ceramic microbead technical field.The composite zirconia ceramic microbead is prepared by 75~85 mass parts yttrium stabilized tetragonal zirconia, 15~25 mass parts alumina, 0.2~1 mass parts silicon dioxide, 0.2~0.5 mass parts magnesium oxide, 2~5 mass parts modified silicon nitride.The present application uses yttrium stabilized tetragonal zirconia as base material, supplemented with alumina and modified silicon nitride, uses the high hardness of alumina, the good combination of modified silicon nitride in formula to improve the overall wear resistance, the results show that the addition of modified silicon nitride is conducive to the formation of uniform and dense microstructure can reduce the probability of grain drop, thereby reducing the grinding of microbead.The composite zirconia ceramic microbead prepared by the present application has high hardness and low self-abrasion, and the raw materials are widely available and the preparation method is simple, so it has good market prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of zirconia ceramic microbeads, and particularly relates to a composite zirconia ceramic microbead and a preparation method thereof. BACKGROUND

[0002] Ultrafine grinding equipment is widely used in new energy battery materials, paint, coating and other fields. Through the mutual impact, extrusion and other complex movements of grinding media, the materials are ground. In the use of ultrafine grinding equipment, the selection of grinding media is a very important problem, which determines the cost, grinding efficiency and product quality after grinding. Common grinding media on the market include glass balls, steel balls, alumina balls, zirconia balls, etc. Among them, glass beads have low strength, large wear and easy to contaminate materials; steel balls have poor corrosion resistance and wear resistance, and are less used; alumina balls (main crystal phase is alpha-alumina) are mainly used for grinding hard mineral materials, but the alumina material has low fracture toughness and poor wear resistance, and is not suitable for high-speed sand mill; zirconia has good comprehensive performance, and belongs to high-end grinding material, but the price and phase change aging of zirconia limit its use in medium and high temperature working conditions, and the hardness of zirconia is lower than that of alumina ball, which limits its application in high-hardness material grinding field.

[0003] In order to improve the comprehensive performance of zirconia, researchers have made some improvements accordingly. For example, CN112500834A discloses a composite zirconia grinding ball for high-purity zirconium carbide powder grinding and a preparation method thereof. The composite zirconia grinding ball is made of yttrium stabilized tetragonal zirconia powder, monoclinic zirconia powder, ultrafine alumina powder and graphite powder in a mass ratio of 60:10~30:1~20:1~5. When sintering in a reducing atmosphere, the oxygen vacancy is controlled to reduce the impurity content, so that the hardness of the composite zirconia grinding ball is improved, and the self-wear and impurity introduction in the grinding process are reduced. However, this method needs to form a reducing gas atmosphere, and the actual oxygen vacancy may be difficult to control with production fluctuations. CN116217270A discloses a production process of diamond film coated medium ball on the surface of zirconia ball. Diamond powder is mixed with composite binder to obtain diamond film powder, and the diamond film coated zirconia ball is mixed with wetting agent to form a diamond film coated zirconia ball, and then sintered to obtain a composite medium ball. However, this method does not test the wear and hardness of the composite medium ball, and the impact resistance of the diamond film may limit the application of the composite medium ball.

[0004] It is still necessary to provide a zirconia ceramic microbead with high hardness and high wear resistance. SUMMARY

[0005] In order to solve the problems in the prior art, the application provides a composite zirconia ceramic micro bead which is prepared from 75-85 parts of yttrium stabilized tetragonal zirconia, 15-25 parts of aluminum oxide, 0.2-1 part of silicon dioxide, 0.2-0.5 part of magnesium oxide and 2-5 parts of modified silicon nitride.

[0006] Zirconia has three crystal structures in normal pressure, namely cubic phase, tetragonal phase and monoclinic phase. Under normal pressure and temperature, the stable crystal of zirconia is monoclinic crystal phase, however, when the temperature of monoclinic crystal zirconia is increased to 1170 DEG C, it will be converted into tetragonal crystal zirconia, and volume shrinkage will be caused during the phase transition process. When the temperature of tetragonal zirconia is reduced to 950 DEG C, it will be converted into monoclinic crystal zirconia, and volume expansion will be caused during the process. In order to prevent the rupture of zirconia ceramic during the sintering process, it is necessary to stabilize the zirconia. Common stabilizers include yttrium oxide, cerium oxide, magnesium oxide, calcium oxide and the like, which can replace zirconium to form a substitutional solid solution to prevent the crystal transformation. Yttrium stabilized tetragonal zirconia has the characteristics of good high temperature resistance, chemical corrosion resistance, wear resistance, oxidation resistance and high hardness, and at the same time, it has a large thermal expansion coefficient, a small heat capacity and a small thermal conductivity, so it is used as a base material in the application. Aluminum oxide has the characteristics of high hardness, high temperature stability and chemical stability, but its fracture toughness is low and its wear resistance is poor, so it is used as an auxiliary material.

[0007] Silicon nitride belongs to a compound combined by covalent bonds, and the basic structural unit is tetrahedron. The silicon atom is located at the center of the tetrahedron, and the nitrogen atom is located at the four vertices of the tetrahedron, forming a continuous and strong network structure. Based on the unique structure, silicon nitride has high Mohs hardness strength and strength, and the strength decreases slowly with the increase of temperature, and has good thermal conductivity and small thermal expansion coefficient. If the addition of silicon nitride is compatible with the formula composition, it is beneficial to improve the hardness and wear resistance of the composite zirconia ceramic micro bead. However, after the direct addition of nano silicon nitride, it is difficult to uniformly disperse in the slurry system of yttrium stabilized tetragonal zirconia, which makes the microstructure of the composite zirconia ceramic micro bead uneven, and instead increases the self-abrasion, bringing more impurities to the ground material. Therefore, it is necessary to modify the nano silicon nitride to enhance its bonding performance with the formula material. Polyvinylpyrrolidone has good film-forming property, and its melting point is different according to the molecular weight, about 110-180 DEG C. After dispersing nano silicon nitride and polyvinylpyrrolidone in alcohol, reducing the temperature to make polyvinylpyrrolidone crystallize on nano silicon nitride to form a coating, modified silicon nitride is formed.

[0008] Further, the preparation method of the modified silicon nitride comprises,

[0009] Mixing polyvinylpyrrolidone, nano-silicon nitride and alcohol with a mass ratio of 1-5:0.5-2:80-150, stirring at a first temperature to obtain a suspension;

[0010] Stirring the suspension at a second temperature, so that the polyvinylpyrrolidone crystallizes and forms a coating on the surface of the nano-silicon nitride, collecting the insoluble substances to obtain modified silicon nitride.

[0011] In order to improve the coating of polyvinylpyrrolidone, heptadecafluorodecyltrimethoxysilane is also added in the coating-crystallization process to reduce the surface tension of nano-silicon nitride and improve the dispersibility of nano-silicon nitride to form a more uniform coating.

[0012] Further, after mixing polyvinylpyrrolidone, nano-silicon nitride and alcohol, heptadecafluorodecyltrimethoxysilane is also added, which accounts for 0.1-0.5 times the mass of nano-silicon nitride.

[0013] Further, the stirring at the first temperature is specifically stirring at 140-160℃ with a rotation speed of 300-500 rpm for 3-18 h;

[0014] The stirring at the second temperature is specifically stirring at 20-30℃ with a rotation speed of 50-100 rpm for 1-5 h;

[0015] The median particle size of the nano-silicon nitride is 20-100 nm;

[0016] The boiling point of the alcohol is higher than 180℃.

[0017] In the present application, the molecular weight of polyvinylpyrrolidone and the type of alcohol are not strictly limited. Illustratively, the molar mass of polyvinylpyrrolidone can be 10000-400000 mol / g; the alcohol can be at least one of n-nonyl alcohol, 2-nonyl alcohol, n-decanol, etc.

[0018] Further, the median particle size of the yttrium-stabilized tetragonal zirconia is 0.2-0.6 μm;

[0019] The median particle size of the alumina is 0.3-0.8 μm;

[0020] The median particle size of the silica is 0.5-1 μm;

[0021] The median particle size of the magnesium oxide is 0.2-0.6 μm.

[0022] The present application also provides a preparation method of the composite zirconia ceramic microbeads described above, comprising,

[0023] Mixing yttrium-stabilized tetragonal zirconia, alumina, silica, magnesium oxide, modified silicon nitride and water, and then grinding to obtain a slurry;

[0024] The slurry is granulated by spraying to form spherical granular powder;

[0025] The spherical granular powder is mixed with water and rolled to form a spherical green body by adopting a rolling forming method;

[0026] The spherical green body is sintered to obtain the composite zirconia ceramic microbead.

[0027] In the present application, a certain proportion of dispersant can be added when yttrium stabilized tetragonal zirconia, alumina, silicon dioxide, magnesium oxide, modified silicon nitride and water are mixed and then ground, which is a conventional operation in the field, and the type of the dispersant is not strictly limited and can be sodium polyacrylate, ammonium polyacrylate, etc., and the addition amount can be 0.1% to 0.5% of the total mass of the slurry.

[0028] Further, the median particle size of the slurry is less than 0.5 μm, and the solid content is 40% to 60%.

[0029] Further, the spraying granulation is performed at a rotation speed of 9000 to 10000 rpm, an inlet temperature of 200 to 250°C, and an outlet temperature of 100 to 120°C.

[0030] Further, the sintering is performed at a temperature of 1400 to 1450°C for 1 to 5 hours.

[0031] Further, the polishing operation is further included after the sintering is completed.

[0032] Compared with the prior art, the present application has the following beneficial effects:

[0033] The present application uses yttrium stabilized tetragonal zirconia as a base material, supplemented with alumina and modified silicon nitride, and uses the high hardness of alumina and the good combination of modified silicon nitride in the formula to improve the overall wear resistance. The results show that the addition of modified silicon nitride is beneficial to the formation of a uniform and dense microstructure, which can reduce the probability of grain detachment, thereby reducing the grinding of the microbead. The composite zirconia ceramic microbead prepared by the present application has high hardness and low self-abrasion, and the raw materials are widely available and the preparation method is simple, which has good market prospects. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0035] Figure 1 The flow chart of the preparation method of the composite zirconia ceramic microbead of the present application is shown.

[0036] Figure 2 A photograph of the composite zirconia ceramic microbeads prepared in the present application is shown;

[0037] Figure 3 A scanning electron microscope image of the modified silicon nitride prepared in Example 1 is shown;

[0038] Figure 4 A scanning electron microscope image of the modified silicon nitride prepared in Example 3 is shown;

[0039] Figure 5 A transmission electron microscope image of the modified silicon nitride prepared in Example 3 is shown;

[0040] Figure 6 A scanning electron microscope image of the composite zirconia ceramic microbeads prepared in Comparative Example 2 is shown;

[0041] Figure 7 A scanning electron microscope image of the composite zirconia ceramic microbeads prepared in Example 1 is shown;

[0042] Figure 8 A scanning electron microscope image of the composite zirconia ceramic microbeads prepared in Example 3 is shown. DETAILED DESCRIPTION

[0043] The endpoints of the ranges and any values disclosed in the present application are not to be understood as limited to the exact values recited as the exact dimensions are not to be construed as being critical. It is intended to convey that a range of values will be encompassed as long as the exact values are within the scope of the disclosed values. The disclosed values are another symptom of being one of ordinary skill in the art's recognition of values which are believed to be the most practical and / or desirable.

[0044] Some of the raw materials used in the examples and comparative examples of the present application are introduced as follows:

[0045] Yttrium stabilized tetragonal zirconia, with a median particle size of 0.5 μm, the sum of the mass fractions of zirconia and zirconia being greater than 99.5%, custom-made by Zhejiang Jin Kun Zirconium Co., Ltd.;

[0046] Alumina, with a median particle size of 0.7 μm, content greater than 99.9%, custom-made by Shandong Shoucheng Chemical Co., Ltd.;

[0047] Silicon dioxide, with a median particle size of 0.6 μm, content greater than 99.9%, custom-made by Beijing Zhongke Keyou Technology Co., Ltd.;

[0048] Magnesium oxide, with a median particle size of 0.6 μm, content greater than 99.9%, custom-made by Dashiqiao Meier Magnesium Products Co., Ltd.;

[0049] Nano-silicon nitride with a median particle size of 50 nm and a content greater than 99.9% was purchased from Hebei Wenlun Metal Materials Co., Ltd.

[0050] Polyvinylpyrrolidone, model PVP-K30, with a molecular weight of approximately 40,000 g / mol, was purchased from Jinan Zhengkang Chemical Co., Ltd.

[0051] Heptadecafluorodecyltrimethoxysilane, model KH-1301, was purchased from Nantong Runfeng Petrochemical Co., Ltd.

[0052] All other raw materials not mentioned are common in the field. The above description is for illustrative purposes only and should not be construed as a strict limitation of the invention. Those skilled in the art can directly purchase commercially available materials or prepare similar or identical materials themselves. These details will not be elaborated upon in the embodiments.

[0053] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] Example 1

[0055] like Figure 1 As shown, a method for preparing composite zirconia ceramic microspheres includes the following steps:

[0056] S1. Ingredients: Weigh 80kg of yttrium-stabilized tetragonal zirconium oxide, 20kg of alumina, 0.5kg of silicon dioxide, 0.3kg of magnesium oxide, 3kg of modified silicon nitride, 0.35kg of sodium polyacrylate, and 103.8kg of water;

[0057] S2. Ball milling pulping: Yttrium-stabilized tetragonal zirconium oxide, alumina, silica, magnesium oxide, modified silicon nitride, sodium polyacrylate and water are added to a ball mill jar and ball milled to obtain a slurry with a median particle size of 0.4 μm and a solid content of 50%.

[0058] S3. Spray granulation: The slurry is fed into a spray granulation dryer. The atomizer of the granulation tower rotates at 9500 rpm, the inlet temperature is 230℃, and the outlet temperature is 110℃ to granulate and obtain spherical powder particles with a diameter of 50μm with good flowability.

[0059] S4. Ball forming: Spray spherical powder and glue into a ball forming machine, mix and roll to form a spherical green body with a diameter of 1mm;

[0060] S5. High-temperature sintering: Transfer the spherical green billet to an automated kiln at 1430℃ and hold for 2 hours to obtain the coarse material;

[0061] S6, surface polishing: the surface of the coarse material is polished to reduce the surface roughness, and the composite zirconia ceramic microbeads as shown in Figure 2 are obtained.

[0062] The preparation method of the modified silicon nitride is as follows:

[0063] 2 kg of polyvinylpyrrolidone, 2 kg of nano silicon nitride, 120 kg of n-nonyl alcohol are mixed, stirred at a temperature of 155°C and a speed of 350 rpm for 12 h; then cooled to 25°C and the speed is reduced to 80 rpm, kept for 2 h, then centrifugal collection of insoluble is transferred to a constant temperature oven at 120°C for drying for 16 h, and the modified silicon nitride is obtained.

[0064] Example 2

[0065] A preparation method of composite zirconia ceramic microbeads is basically the same as that in Example 1, except that the preparation method of the modified silicon nitride is as follows:

[0066] 2 kg of polyvinylpyrrolidone, 2 kg of nano silicon nitride, 0.2 kg of heptadecafluorodecyltrimethoxysilane, 120 kg of n-nonyl alcohol are mixed, stirred at a temperature of 155°C and a speed of 350 rpm for 12 h; then cooled to 25°C and the speed is reduced to 80 rpm, kept for 2 h, then centrifugal collection of insoluble is transferred to a constant temperature oven at 120°C for drying for 16 h, and the modified silicon nitride is obtained.

[0067] Example 3

[0068] A preparation method of composite zirconia ceramic microbeads is basically the same as that in Example 1, except that the preparation method of the modified silicon nitride is as follows:

[0069] 2 kg of polyvinylpyrrolidone, 2 kg of nano silicon nitride, 0.8 kg of heptadecafluorodecyltrimethoxysilane, 120 kg of n-nonyl alcohol are mixed, stirred at a temperature of 155°C and a speed of 350 rpm for 12 h; then cooled to 25°C and the speed is reduced to 80 rpm, kept for 2 h, then centrifugal collection of insoluble is transferred to a constant temperature oven at 120°C for drying for 16 h, and the modified silicon nitride is obtained.

[0070] Example 4

[0071] A preparation method of composite zirconia ceramic microbeads is basically the same as that in Example 1, except that the preparation method of the modified silicon nitride is as follows:

[0072] 2kg polyvinylpyrrolidone, 2kg nanometer silicon nitride, 1kg heptadecafluorodecyltrimethoxysilane, 120kg n-nonyl alcohol were mixed, and then stirred at a temperature of 155℃ and a rotating speed of 350rpm for 12h; then the temperature was lowered to 25℃ and the rotating speed was lowered to 80rpm, and maintained for 2h, and then the insoluble substances were collected by centrifugation and transferred to a constant temperature oven at 120℃ for drying for 16h to obtain modified silicon nitride.

[0073] Comparative Example 1

[0074] A preparation method of a composite zirconia ceramic microbead, which is basically the same as that of Example 1, except that the preparation method of the modified silicon nitride is as follows:

[0075] 2kg polyvinylpyrrolidone, 2kg nanometer silicon nitride, 1.2kg heptadecafluorodecyltrimethoxysilane, 120kg n-nonyl alcohol were mixed, and then stirred at a temperature of 155℃ and a rotating speed of 350rpm for 12h; then the temperature was lowered to 25℃ and the rotating speed was lowered to 80rpm, and maintained for 2h, and then the insoluble substances were collected by centrifugation and transferred to a constant temperature oven at 120℃ for drying for 16h to obtain modified silicon nitride.

[0076] Comparative Example 2

[0077] A preparation method of a composite zirconia ceramic microbead, which comprises the following steps:

[0078] S1, batching: 80kg yttrium-stabilized tetragonal zirconia, 20kg alumina, 0.5kg silicon dioxide, 0.3kg magnesium oxide, 3kg nanometer silicon nitride, 0.35kg sodium polyacrylate, and 103.8kg water were weighed;

[0079] S2, ball milling to prepare slurry: the yttrium-stabilized tetragonal zirconia, alumina, silicon dioxide, magnesium oxide, nanometer silicon nitride, sodium polyacrylate and water were added into a ball mill tank for ball milling to obtain a slurry with a median particle size of 0.4μm and a solid content of 50%;

[0080] S3, spray granulation: the slurry was fed into a spray granulation dryer, the rotating speed of the granulation tower atomizer was 9500rpm, the inlet temperature was 230℃, and the outlet temperature was 110℃ for granulation to obtain spherical granular powder with good fluidity and a diameter of 50μm;

[0081] S4, rolling ball forming: the spherical granular powder and glue were sprayed into a rolling ball forming machine to mix and roll to form spherical green bodies with a diameter of 1mm;

[0082] S5, high-temperature sintering: the spherical green bodies were transferred to an automatic kiln at 1430℃ for heat preservation for 2h to obtain a coarse material;

[0083] S6, surface polishing: the surface of the coarse material was polished to reduce the surface roughness to obtain a composite zirconia ceramic microbead.

[0084] Comparative Example 3

[0085] A preparation method of a composite zirconia ceramic microbead, steps are as follows,

[0086] S1, batching: 80 kg of yttrium stabilized tetragonal zirconia, 20 kg of alumina, 0.5 kg of silicon dioxide, 0.3 kg of magnesium oxide, 0.35 kg of sodium polyacrylate, 103.8 kg of water;

[0087] S2, ball milling to make slurry: the yttrium stabilized tetragonal zirconia, alumina, silicon dioxide, magnesium oxide, sodium polyacrylate and water are added into a ball mill tank, and ball milling is carried out to obtain a slurry with a median particle size of 0.4 μm and a solid content of 50%;

[0088] S3, spray granulation: the slurry is sent into a spray granulation dryer, the granulation tower atomizer rotates at 9500 rpm, the inlet temperature is 230℃, and the outlet temperature is 110℃ for granulation to obtain spherical particle powder with good fluidity and a diameter of 50 μm;

[0089] S4, ball forming: the spherical particle powder and glue are sprayed into a ball forming machine to mix and roll to form a spherical green body with a diameter of 1 mm;

[0090] S5, high temperature sintering: the spherical green body is transferred to an automatic kiln at 1430℃ for 2h to obtain a coarse material;

[0091] S6, surface polishing: the surface of the coarse material is polished to reduce the surface roughness to obtain a composite zirconia ceramic microbead.

[0092] Test Example

[0093] The microstructure of the modified silicon nitride prepared in Example 1 and Example 3 was observed by scanning electron microscopy, and the results are shown in Figure 3 and Figure 4 It can be seen from Figure 3 that an uneven coating structure is formed on the surface of the nano silicon nitride, and the nano silicon nitride has a certain agglomeration. From Figure 4 , it can be seen that the agglomeration of the nano silicon nitride is reduced, but the coating is not obvious. The structure of the modified silicon nitride prepared in Example 3 was observed by transmission electron microscopy, as shown in Figure 5 , it is further concluded that the addition of heptadecafluorodecyltrimethoxysilane improves the dispersion performance of the nano silicon nitride and the coating of polyvinylpyrrolidone.

[0094] The microstructure of the composite zirconia ceramic microbead of Comparative Example 2, Example 1 and Example 3 was also observed by scanning electron microscopy, and the results are shown in Figure 6~Figure 8 . From Figure 6It can be seen from the micrograph that the microbeads prepared by adding nano-silicon nitride are not uniform in microstructure; from Figure 7 It can be seen from the micrograph that the microbeads prepared by using polyvinylpyrrolidone coated silicon nitride are significantly more uniform than those of Comparative Example 2; from Figure 8 It can be seen from the micrograph that the microbeads prepared by using polyvinylpyrrolidone and heptadecafluorodecyltrimethoxysilane coated silicon nitride have a uniform and dense microstructure.

[0095] The composite zirconia ceramic microbeads prepared in the examples and comparative examples were tested for density, hardness and self-abrasion according to the standard JC / T 2136-2012 "Microcrystalline zirconia abrasive media balls"; for grinding of high-purity zirconium carbide powder, the zirconia content introduced at the end of the belt grinding was detected, i.e. the abrasion amount; the crushing strength of the composite zirconia ceramic microbeads prepared in the examples and comparative examples was tested by a crushing strength tester. These results are shown in Table 1.

[0096] Table 1 Test results of composite zirconia ceramic microbeads

[0097]

[0098] It can be seen from the test results in Table 1 that the composite zirconia ceramic microbeads prepared in Examples 2-4 have higher Vickers hardness, lower self-abrasion, lower abrasion amount and higher crushing strength, because the appropriate amount of polyvinylpyrrolidone and heptadecafluorodecyltrimethoxysilane is introduced to modify the nano-silicon nitride, which is beneficial to good coating of the nano-silicon nitride, and the addition of the modified silicon nitride is beneficial to the formation of a uniform and dense microstructure to reduce the probability of grain detachment, thereby reducing the grinding of the microbeads and improving the overall strength.

[0099] Finally, it should be noted that: the above only describes the preferred embodiments of the present application and is not intended to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent replacements for some technical features, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A composite zirconia ceramic microsphere, characterized in that, It was prepared from 75-85 parts by mass of yttrium-stabilized tetragonal zirconium oxide, 15-25 parts by mass of alumina, 0.2-1 parts by mass of silicon dioxide, 0.2-0.5 parts by mass of magnesium oxide, and 2-5 parts by mass of modified silicon nitride; The method for preparing the modified silicon nitride includes, Polyvinylpyrrolidone, nano-silicon nitride, and alcohol are mixed in a mass ratio of 1~5:0.5~2:80~150 and stirred at a first temperature to obtain a suspension. The suspension was stirred at a second temperature to allow polyvinylpyrrolidone to crystallize and form a coating on the surface of nano-silicon nitride. The insoluble matter was collected to obtain modified silicon nitride. After mixing polyvinylpyrrolidone, nano-silicon nitride, and alcohol, heptadecafluorodecyltrimethoxysilane, accounting for 0.1 to 0.5 times the mass of nano-silicon nitride, is added.

2. The composite zirconia ceramic microspheres according to claim 1, characterized in that, The stirring at the first temperature specifically involves stirring at 140~160℃ and a speed of 300~500rpm for 3~18h; The stirring at the second temperature specifically involves stirring at 20-30°C at a speed of 50-100 rpm for 1-5 hours. The median particle size of the nano-silicon nitride is 20~100nm; The alcohol has a boiling point above 180°C.

3. The composite zirconia ceramic microspheres according to claim 1, characterized in that, The median particle size of the yttrium-stabilized tetragonal zirconium oxide is 0.2~0.6 μm; The median particle size of the alumina is 0.3~0.8 μm; The median particle size of the silica is 0.5~1μm; The median particle size of the magnesium oxide is 0.2~0.6 μm.

4. A method for preparing composite zirconia ceramic microspheres as described in any one of claims 1 to 3, characterized in that, include, Yttrium-stabilized tetragonal zirconium oxide, aluminum oxide, silicon dioxide, magnesium oxide, modified silicon nitride, and water were mixed and ground to obtain a slurry. The slurry is granulated by spraying to form spherical particles; The ball-forming process is used to form spherical green bodies from spherical particles and water. Sintering of spherical green bodies yields composite zirconia ceramic microspheres.

5. The method for preparing composite zirconia ceramic microspheres according to claim 4, characterized in that, The slurry has a median particle size of less than 0.5 μm and a solid content of 40% to 60%.

6. The method for preparing composite zirconia ceramic microspheres according to claim 4, characterized in that, Spray granulation was carried out at a rotation speed of 9000~10000 rpm, an inlet temperature of 200~250℃, and an outlet temperature of 100~120℃.

7. The method for preparing composite zirconia ceramic microspheres according to claim 4, characterized in that, The sintering process is carried out at a temperature of 1400~1450℃ for 1~5 hours.

8. The method for preparing composite zirconia ceramic microspheres according to claim 4, characterized in that, Polishing is also included after sintering.

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