A zirconia composite ceramic microsphere and a preparation method thereof

Abstract

The present invention discloses a zirconia composite ceramic microsphere and a preparation method thereof, belonging to the technical field of zirconia ceramic microspheres. The zirconia composite ceramic microsphere is prepared from 80 to 90 parts by mass of yttrium-stabilized tetragonal zirconia powder, 5 to 10 parts by mass of alumina powder, and 5 to 10 parts by mass of silicon carbide composite powder. The present invention uses yttrium-stabilized tetragonal zirconia as the base material, supplemented with alumina and polycrystalline and multi-granularity silicon carbide composite powder. The highly wear-resistant and highly corrosion-resistant silicon carbide powder is used to improve the overall wear resistance and corrosion resistance of the composite ceramic microsphere. After the addition of the silicon carbide composite powder, the Vickers hardness and strength of the zirconia composite ceramic microsphere are significantly improved, the wear rate is greatly reduced, and the mass loss rate after soaking in a strong acid solution is greatly reduced. The zirconia composite ceramic microsphere prepared by the present invention has excellent wear resistance and good corrosion resistance. At the same time, the raw materials are widely available and the preparation method is simple, having a good market prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of zirconia ceramic microspheres, and particularly to a zirconia composite ceramic microsphere and a preparation method thereof. Background Art

[0002] Ultra-fine grinding equipment is widely used in fields such as new energy battery materials, paints, and coatings. Through various complex movements such as the mutual impact and extrusion of grinding media, the materials are pulverized. In the use of ultra-fine grinding equipment, the selection of grinding media is a very important issue, which determines the cost, grinding efficiency, and the quality of the pulverized products during the grinding process. Common grinding media on the market include glass balls, steel balls, alumina balls, zirconia balls, etc. Zirconia ceramic microspheres stand out among many ceramic grinding media due to their outstanding advantages such as high strength, high hardness, excellent wear resistance, and corrosion resistance, and are highly favored by the ceramic industry and belong to high-end grinding materials. However, the hardness of zirconia is relatively low, and its acid corrosion resistance is not good, which limits its application in the fields of grinding high-hardness materials and acidic materials.

[0003] In order to improve the comprehensive properties of zirconia, researchers have made some corresponding improvements. For example, CN112500834A discloses a zirconia composite grinding ball for grinding high-purity zirconium carbide powder and a preparation method thereof. The zirconia composite grinding ball is made of yttrium-stabilized tetragonal zirconia powder, monoclinic zirconia powder, ultra-fine alumina powder, and graphite powder in a mass ratio of 60:10~30:1~20:1~5. This patent improves the hardness of ceramic microspheres by incorporating alumina powder with higher hardness into zirconia powder. However, although the hardness of alumina is higher than that of zirconia, the overall hardness of zirconia microspheres is limitedly improved under a certain incorporation amount. At the same time, the wear resistance and acid corrosion resistance of alumina are poor. CN116217270A discloses a production process of a diamond film-coated zirconia ball surface medium ball. Diamond micro-powder is mixed with a composite binder to obtain diamond film-coated powder, and the wetted zirconia balls are mixed evenly to form zirconia balls coated with a diamond film, and then sintered to obtain a composite medium ball. However, this method does not test the wear amount and hardness of the composite medium ball. At the same time, the impact resistance of the diamond film may limit the application of the composite medium ball. In addition, the particle size D50 of the diamond micro-powder used in this patent is ≤200 nm, and such small-particle-size diamond powder is difficult to obtain and has a high cost, which may limit its large-scale application. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a zirconia composite ceramic microsphere and a preparation method thereof.

[0005] As an aspect of the present invention, the present invention provides a preparation method of a zirconia composite ceramic microsphere, which includes,

[0006] Mix yttria-stabilized tetragonal zirconia, alumina, silicon carbide composite powder and water, and grind to obtain a slurry; the mass ratio of yttria-stabilized tetragonal zirconia to silicon carbide composite powder is (80 - 90):(5 - 10);

[0007] Spray granulate the obtained slurry to form spherical particles;

[0008] Adopt the form of ball rolling molding to form a spherical green body from the spherical particles and glue;

[0009] Sinter the spherical green body to obtain zirconia composite ceramic microspheres;

[0010] The silicon carbide composite powder is made of silicon carbide powders with α hexagonal structure and β cubic structure respectively, and the mass ratio of the two is (20 - 25):(70 - 78).

[0011] Preferably, the silicon carbide composite powder is formed by compounding type A silicon carbide, type B silicon carbide and type C silicon carbide. Among them, the crystal form of type A silicon carbide is α hexagonal structure, the median particle size is 0.6 - 0.8 μm, and its mass accounts for 20% - 25% of the total weight of the silicon carbide composite powder; the crystal form of type B silicon carbide is β cubic structure, the median particle size is 0.3 - 0.5 μm, and its mass accounts for 65% - 75% of the total weight of the silicon carbide composite powder; the crystal form of type C silicon carbide is β cubic structure, the median particle size is 50 - 90 nm, and its mass accounts for 5% - 10% of the total weight of the silicon carbide composite powder.

[0012] Preferably, the preparation method of the silicon carbide composite powder includes the following steps: Disperse the powders of type A silicon carbide, type B silicon carbide and type C silicon carbide in ethanol to form a slurry with a solid content of 50%, put it into a drum mixer and stir at 50 - 100 rpm for 2 - 3 h, and dry to obtain the silicon carbide composite powder.

[0013] Preferably, the mass parts of yttria-stabilized tetragonal zirconia and alumina are (80 - 90):(5 - 10) respectively.

[0014] Preferably, the median particle size of the yttria-stabilized tetragonal zirconia powder is 0.2 - \alphaμm, and the median particle size of the alumina powder is 0.3 - 0.8 μm.

[0015] Preferably, the median particle size of the slurry is less than 0.5 μm and the solid content is 40% - 60%.

[0016] Preferably, spray granulation is carried out at a rotation speed of 9000 - 10000 rpm, an inlet temperature of 200 - 250 °C, and an outlet temperature of 100 - 120 °C.

[0017] Preferably, the sintering is carried out at a temperature of 1520-1600 °C for 1-3 h.

[0018] Preferably, a polishing operation is further included after the sintering is completed.

[0019] The present invention also provides a zirconia composite ceramic microsphere, which is prepared from 80-90 parts by mass of yttrium-stabilized tetragonal zirconia powder, 5-10 parts by mass of alumina powder, and 5-10 parts by mass of silicon carbide composite powder.

[0020] Zirconia has three crystal structures under normal pressure, namely cubic phase, tetragonal phase, and monoclinic phase. Under normal pressure and temperature, the stable crystal of zirconia is the monoclinic phase. However, when the temperature of monoclinic zirconia rises to 1170 °C, it will transform into tetragonal zirconia, and volume shrinkage will occur during the phase change process. When the temperature of tetragonal zirconia drops to 950 °C, it will transform into monoclinic zirconia, and volume expansion will occur during this process. In order to prevent the cracking of zirconia ceramics during the sintering process, zirconia needs to be stabilized. Common stabilizers include yttrium oxide, cerium oxide, magnesium oxide, calcium oxide, etc., which can replace zirconium to form substitutional solid solutions to prevent phase transformation. Yttrium-stabilized tetragonal zirconia has good high-temperature resistance, chemical corrosion resistance, wear resistance, oxidation resistance, high hardness, etc., and at the same time has a relatively large thermal expansion coefficient, a small heat capacity and thermal conductivity. Therefore, the present invention uses yttrium-stabilized tetragonal zirconia as the base material. Alumina has characteristics such as 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.

[0021] Due to its stable chemical properties, high thermal conductivity, low coefficient of thermal expansion, and good wear resistance, silicon carbide is commonly used in abrasive, mechanical chemical seals, and other fields related to wear-resistant parts. Silicon carbide has a very high hardness, with a Mohs hardness of 9.5, second only to diamond (Mohs hardness 10), the hardest substance in the world. There are at least 70 crystalline forms of silicon carbide, and the more common crystal forms are mainly the α-type with a hexagonal / rhombohedral structure and the β-type with a cubic structure. The α-type silicon carbide has high hardness, high wear resistance, and high corrosion resistance, and is a thermodynamically stable phase at high temperatures. The β-type silicon carbide has a higher surface energy and higher sintering activity, and is easy to form a dense body at low temperatures, and will transform into the α-type silicon carbide at high temperatures. In addition, silicon carbide powder can be divided into micron-sized, sub-micron-sized, and nano-sized according to particle size. The smaller the particle size of silicon carbide powder, the higher the sintering activity, the easier it is to agglomerate, and the cost will increase. The A, B, and C types of silicon carbide used in this patent are sub-micron-sized (0.6 - 0.8 μm) α-type, sub-micron-sized (0.3 - 0.5 μm) β-type, and nano-sized (50 - 90 nm) β-type silicon carbide powder respectively. The silicon carbide composite powder provided by this patent uses sub-micron-sized α-type silicon carbide powder as the aggregate, sub-micron-sized β-type silicon carbide powder as the matrix material, and is supplemented with a small amount of nano-sized β-type silicon carbide powder to further improve the sintering activity. Without affecting the overall dispersibility of the powder, a silicon carbide composite powder with good sintering activity is formed, so as to ensure that the composite ceramic microspheres sintered after mixing with zirconia and alumina powder have the characteristics of denseness, high hardness, wear resistance, and corrosion resistance.

[0022] Furthermore, the preparation method of the silicon carbide composite powder includes

[0023] Mix the A-type, B-type, and C-type silicon carbide powders in a mass ratio of 20 - 25:65 - 75:5 - 10, disperse them in ethanol to form a slurry with a solid content of 50%, put it into a drum mixer and stir at 50 - 100 rpm for 2 - 3 h, and then continue to dry it in an 80-degree Celsius oven to obtain the silicon carbide composite powder.

[0024] Furthermore, the median particle size of the yttrium-stabilized tetragonal zirconia is 0.2 - 0.6 μm; the median particle size of the alumina is 0.3 - 0.8 μm;

[0025] The present invention also provides a preparation method of the above-mentioned zirconia composite ceramic microspheres, including

[0026] Mix yttrium-stabilized tetragonal zirconia, alumina, silicon carbide composite powder, and water and grind them to obtain a slurry;

[0027] Spray granulate the slurry to form spherical particle powder;

[0028] Adopt a rolling forming method to mix the spherical powder with glue (binder) and roll it into a spherical green body;

[0029] The spherical green body is sintered to obtain yttria-stabilized zirconia composite ceramic microspheres.

[0030] In the present invention, when the yttria-stabilized tetragonal zirconia, alumina, silicon carbide composite powder and water are mixed and then ground, a certain proportion of dispersant can also be added, which is a conventional operation in the art. The type of the dispersant does not need to be strictly limited and can be sodium polyacrylate, ammonium polyacrylate, etc. The addition amount can be 0.1% - 0.5% of the total mass of the slurry.

[0031] Furthermore, the median particle size of the slurry is less than 0.5 μm and the solid content is 40% - 60%.

[0032] Furthermore, spray granulation is carried out at a rotational speed of 9000 - 10000 rpm, an inlet temperature of 200 - 250 °C, and an outlet temperature of 100 - 120 °C.

[0033] Furthermore, the sintering is carried out at a temperature of 1500 - 1600 °C for 1 - 5 h.

[0034] Furthermore, a polishing operation is included after the sintering is completed.

[0035] Compared with the prior art, the technical inventive points of the present invention are as follows:

[0036] Silicon carbide powder is compounded with zirconia powder. Through the high hardness, high wear resistance and high corrosion resistance of silicon carbide, the overall hardness, wear resistance and corrosion resistance of the yttria-stabilized zirconia composite ceramic microspheres are improved, and their applications in the fields of grinding of high-hardness materials and acidic materials are broadened.

[0037] Silicon carbide composite powder is prepared by compounding different crystal forms of silicon carbide powder. The hardness and wear resistance of α-type silicon carbide powder are good, but its sintering activity is relatively low. The sintering activity of β-type silicon carbide powder is high and it can be transformed into the α-phase at high temperature. When the two are mixed in a suitable proportion, it can ensure that the yttria-stabilized zirconia composite ceramic microspheres sintered at 1500 - 1600 °C are both dense and have high hardness and high wear resistance.

[0038] Silicon carbide composite powder is prepared by compounding silicon carbide powder with a specific particle size. Submicron silicon carbide powder has good sintering activity and is easy to obtain. The sintering activity of nano-scale silicon carbide powder is higher, but its cost is high and it is easy to agglomerate. In this patent, a large amount of submicron silicon carbide powder is supplemented with a small amount of nano-scale silicon carbide powder to obtain a silicon carbide composite powder with good sintering activity and dispersibility. Description of the Drawings

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0040] Figure 1 The flowchart of the preparation method of the zirconia composite ceramic microspheres of the present invention is shown;

[0041] Figure 2 The physical photo of the zirconia composite ceramic microspheres prepared in Example 1 of the present invention is shown;

[0042] Figure 3 The SEM photo of the zirconia composite ceramic microspheres prepared in Example 1 of the present invention is shown;

[0043] Figure 4 The SEM photo of the zirconia composite ceramic microspheres prepared in Example 2 of the present invention is shown;

[0044] Figure 5 The SEM photo of the zirconia composite ceramic microspheres prepared in Example 3 of the present invention is shown. Detailed implementation manners

[0045] In the ranges disclosed in the present invention, the endpoints and any values of the ranges are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in the present invention.

[0046] Some raw materials used in the embodiments and comparative examples of the present invention are introduced as follows:

[0047] Yttria-stabilized tetragonal zirconia, with a median particle size of 0.5 μm, the sum of the mass fractions of yttria and zirconia is greater than 99.5%, yttria 5.4 ± 0.2%, zirconia 94.6 ± 0.2%, prepared by the co-precipitation method in Zhejiang Jinkun Zirconium Industry Co., Ltd.;

[0048] Aluminum oxide, with a median particle size of 0.7 μm, content greater than 99.9%, purchased from Shandong Shoucheng Chemical Co., Ltd.;

[0049] Type A silicon carbide powder, median particle size 0.8 μm, crystal form is α-type. Type B silicon carbide powder, median particle size 0.5 μm, crystal form is β-type. Type C silicon carbide powder, median particle size 80 nm, crystal form is β-type. The above three types of silicon carbide powders are all purchased from Shaoxing Jingcai Technology Co., Ltd.

[0050] All other raw materials not mentioned are common raw materials in the art. The above content is only for helping to explain the present invention and should not be construed as a strict limitation of the present invention. Those skilled in the art can directly purchase from the market or prepare the same / similar raw materials by themselves. These contents will not be elaborated in the embodiments anymore.

[0051] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with specific embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0052] Embodiment 1. A method for preparing zirconia composite ceramic microspheres comprises the following steps:

[0053] S1. Batching: Weigh 80 kg of yttrium-stabilized tetragonal zirconia, 10 kg of alumina, 10 kg of silicon carbide composite powder, and 100 kg of water;

[0054] S2. Ball milling for pulping: Add yttrium-stabilized tetragonal zirconia, alumina, silicon carbide composite powder, and water into a ball milling tank for ball milling to obtain a slurry with a median particle size of 0.4 μm and a solid content of 50%;

[0055] S3. Spray granulation: Feed the slurry into a spray granulation dryer, and granulate at a rotational speed of 9500 rpm of the atomizer in the granulation tower, an inlet temperature of 230 °C, and an outlet temperature of 110 °C to obtain spherical particles with a good fluidity and a diameter of 50 μm;

[0056] S4. Rolling ball forming: Spray the spherical particles and glue into a rolling ball forming machine, adjust the rolling time to form a spherical green body with a median particle size of 1 mm, and the spherical green body is 0.9 mm - 1.1 mm;

[0057] S5. High-temperature sintering: Transfer the spherical green body to an automatic kiln at 1580 °C for heat preservation for 2 h to obtain rough materials;

[0058] S6. Surface polishing: Polish the surface of the rough materials to reduce the surface roughness.

[0059] Among them, the preparation method of the silicon carbide composite powder is: Mix 2.5 kg of type A silicon carbide powder, 6.5 kg of type B silicon carbide powder, 1 kg of type C silicon carbide powder, and 10 kg of ethanol, then put them into a drum mixer and stir at 100 rpm for 2 h, and then continue to put them into an oven at 80 °C for drying to obtain the silicon carbide composite powder.

[0060] Example 2: A method for preparing zirconium oxide composite ceramic microbeads, comprising the following steps:

[0061] S1. Ingredients: Weigh 84 kg yttrium-stabilized tetragonal zirconia, 10 kg alumina, 6 kg silicon carbide composite powder, and 100 kg water;

[0062] S2. Ball milling: Add yttrium-stabilized tetragonal zirconia, alumina, silicon carbide composite powder and water into a ball mill and perform ball milling to obtain a slurry with a median particle size of 0.4 μm and a solid content of 50%;

[0063] S3, spray granulation: the slurry was fed into a spray granulation dryer, the granulation tower atomizer speed was 9500 rpm, the inlet temperature was 230 °C, and the outlet temperature was 110 °C for granulation to obtain spherical particles with good fluidity and a diameter of 50 μm;

[0064] S4, ball forming: spherical particles and glue are sprayed into a ball forming machine to form a spherical green body with a diameter of 1 mm;

[0065] S5. High-temperature sintering: The spherical green body is transferred to an automated kiln at 1520°C and kept at this temperature for 2 h to obtain a coarse material;

[0066] S6. Surface polishing: polish the surface of the rough material.

[0067] The preparation method of silicon carbide composite powder is as follows: 1.5 kg of type A silicon carbide powder, 3.9 kg of type B silicon carbide powder, 0.6 kg of type C silicon carbide powder and 6 kg of ethanol are mixed and placed in a drum mixer and stirred at 100 rpm for 2 hours, and then placed in an oven at 80 degrees Celsius for drying to obtain silicon carbide composite powder.

[0068] Example 3: A method for preparing zirconium oxide composite ceramic microbeads, comprising the following steps:

[0069] S1. Ingredients: Weigh 80 kg of yttrium-stabilized tetragonal zirconia, 10 kg of alumina, 10 kg of silicon carbide composite powder, and 100 kg of water;

[0070] S2. Ball milling: Add yttrium-stabilized tetragonal zirconia, alumina, silicon carbide composite powder and water into a ball mill and perform ball milling to obtain a slurry with a median particle size of 0.4 μm and a solid content of 50%;

[0071] S3, spray granulation: the slurry was fed into a spray granulation dryer, the granulation tower atomizer speed was 9500 rpm, the inlet temperature was 230 °C, and the outlet temperature was 110 °C for granulation to obtain spherical particles with good fluidity and a diameter of 50 μm;

[0072] S4. Rolling ball forming: Spraying spherical particles and glue into a rolling ball forming machine to form spherical green compacts with a diameter of 1 mm;

[0073] S5. High-temperature sintering: Transferring the spherical green compacts to an automated furnace at 1600 °C and holding for 2 h to obtain coarse materials;

[0074] S6. Surface polishing: Polishing the surface of the coarse materials.

[0075] Among them, the preparation method of the silicon carbide composite powder is as follows: Mixing 2 kg of type A silicon carbide powder, 7.5 kg of type B silicon carbide powder, 0.5 kg of type C silicon carbide powder and 10 kg of ethanol, putting them into a drum mixer and stirring at 80 rpm for 1.5 h, and then putting them into an oven at 80 °C to dry to obtain the silicon carbide composite powder.

[0076] Example 4. A preparation method of yttria-stabilized zirconia composite ceramic microspheres, the steps are as follows.

[0077] S1. Batching: Weighing 82 kg of yttria-stabilized tetragonal zirconia, 10 kg of alumina, 8 kg of silicon carbide composite powder, and 100 kg of water;

[0078] S2. Ball milling for pulping: Adding yttria-stabilized tetragonal zirconia, alumina, silicon carbide composite powder and water into a ball milling tank for ball milling to obtain a slurry with a median particle size of 0.4 μm and a solid content of 50%;

[0079] S3. Spray granulation: Feeding the slurry into a spray granulation dryer, with the atomizer speed in the granulation tower being 9500 rpm, the inlet temperature being 230 °C, and the outlet temperature being 110 °C for granulation to obtain spherical particles with good fluidity and a diameter of 50 μm;

[0080] S4. Rolling ball forming: Spraying spherical particles and glue into a rolling ball forming machine to form spherical green compacts with a diameter of 1 mm;

[0081] S5. High-temperature sintering: Transferring the spherical green compacts to an automated furnace at 1560 °C and holding for 2 h to obtain coarse materials;

[0082] S6. Surface polishing: Polishing the surface of the coarse materials.

[0083] Among them, the preparation method of the silicon carbide composite powder is as follows: Mixing 1.6 kg of type A silicon carbide powder, 5.6 kg of type B silicon carbide powder, 0.8 kg of type C silicon carbide powder and 8 kg of ethanol, putting them into a drum mixer and stirring at 100 rpm for 1.5 h, and then putting them into an oven at 80 °C to dry to obtain the silicon carbide composite powder.

[0084] Comparative Example 1: A method for preparing zirconium oxide composite ceramic microbeads is basically the same as that of Example 1, except that: the method for preparing silicon carbide composite powder is:

[0085] 2.5 kg of type A silicon carbide powder, 7.5 kg of type B silicon carbide powder and 10 kg of ethanol were mixed and placed in a drum mixer and stirred at 100 rpm for 2 h. The mixture was then placed in an oven at 80 degrees Celsius for drying to obtain silicon carbide composite powder.

[0086] Comparative Example 2: A method for preparing zirconium oxide composite ceramic microbeads is basically the same as that of Example 1, except that: the method for preparing silicon carbide composite powder is:

[0087] 2.5 kg of type A silicon carbide powder, 7.5 kg of type C silicon carbide powder and 10 kg of ethanol were mixed and placed in a drum mixer and stirred at 100 rpm for 2 h. The mixture was then placed in an oven at 80 degrees Celsius for drying to obtain silicon carbide composite powder.

[0088] Comparative Example 3: A method for preparing zirconium oxide composite ceramic microbeads. The method for preparing zirconium oxide composite ceramic microbeads is basically the same as that in Example 1, except that: the method for preparing silicon carbide composite powder is:

[0089] 10 kg of type A silicon carbide powder and 10 kg of ethanol were mixed and placed in a drum mixer and stirred at 100 rpm for 2 h, and then placed in an oven at 80 degrees Celsius for drying to obtain silicon carbide composite powder.

[0090] Comparative Example 4: A method for preparing zirconium oxide composite ceramic microbeads. The method for preparing zirconium oxide composite ceramic microbeads is basically the same as that in Example 1, except that the method for preparing silicon carbide composite powder is:

[0091] 9 kg of type B silicon carbide powder, 1 kg of type C silicon carbide powder and 10 kg of ethanol were mixed and placed in a drum mixer and stirred at 100 rpm for 2 h, and then placed in an oven at 80 degrees Celsius for drying to obtain silicon carbide composite powder.

[0092] Comparative Example 5: A method for preparing zirconium oxide composite ceramic microbeads, comprising the following steps:

[0093] S1. Ingredients: Weigh 90 kg of yttrium-stabilized tetragonal zirconia, 10 kg of alumina, and 100 kg of water;

[0094] S2. Ball milling: Yttrium-stabilized tetragonal zirconia, alumina, and water were added to a ball mill and ball milled to obtain a slurry with a median particle size of 0.4 μm and a solid content of 50%;

[0095] S3. Spray granulation: Feed the slurry into a spray granulation dryer. Granulate at a rotational speed of 9,500 rpm of the atomizer in the granulation tower, an inlet temperature of 230 °C, and an outlet temperature of 110 °C to obtain spherical particles with a diameter of 50 μm and good fluidity;

[0096] S4. Ball rolling forming: Spray the spherical particles and glue into a ball rolling forming machine to form a green spherical body with a diameter of 1 mm;

[0097] S5. High-temperature sintering: Transfer the green spherical body to an automated kiln at 1,450 °C and keep it warm for 2 h to obtain the rough material;

[0098] S6. Surface polishing: Polish the surface of the rough material.

[0099] The zirconia composite ceramic microspheres prepared in all the examples and comparative examples were subjected to density, hardness, and self-abrasion tests with reference to the standard JC / T 2136-2012 "Microcrystalline Zirconia Grinding Media Balls"; for the grinding of high-purity zirconium carbide powder, the zirconia content finally introduced in the belt grinding was detected, which was the wear amount; the crushing strength of the zirconia composite ceramic microspheres prepared in all the examples and comparative examples was tested using a crushing strength tester. The mass loss rate of the zirconia composite ceramic microspheres prepared in all the examples and comparative examples after being soaked in 10% sulfuric acid was tested with reference to the national standard GB / T 4738-2015 "Determination Method for Acid and Alkali Resistance of Domestic Ceramic Materials". These results are shown in Table 1.

[0100] Table 1 Test Results of Zirconia Composite Ceramic Microspheres

[0101] ,

[0102] It can be seen from the test results in Table 1 that the zirconia composite ceramic microspheres prepared in Examples 1 to 4 of the present invention have appropriate density, higher hardness and crushing strength, lower self-wear and wear amount, and lower acid-bubble mass loss rate, showing high hardness, high strength, high wear resistance and high corrosion resistance. In Comparative Example 1, C-type nano-silicon carbide powder was not used for auxiliary sintering, and the sintering activity of the composite silicon carbide ceramic powder decreased, and the sintering density of the ceramic microspheres decreased, resulting in a decrease in their density, strength, wear resistance and corrosion resistance. In Comparative Example 2, too much C-type nano-silicon carbide powder was used, and the composite silicon carbide ceramic powder agglomerated, which also affected the sintering density of the ceramic microspheres and the dispersion uniformity of the silicon carbide phase in the composite ceramic microspheres, resulting in a decrease in the overall wear resistance, hardness, strength and corrosion resistance of the composite ceramic microspheres. In Comparative Example 3, only A-type silicon carbide powder was used. The A-type silicon carbide powder has a higher hardness but a poor sintering activity, which also leads to a decrease in the sintering density of the composite ceramic microspheres, but has a small impact on the hardness. The overall density, wear resistance, strength and corrosion resistance of the composite ceramic microspheres decrease. In Comparative Example 4, only B-type and C-type silicon carbide powders were used. The B-type and C-type silicon carbide powders have relatively high sintering activity, but they need to be completely converted into the α phase at high temperature to show corrosion resistance and wear resistance. In order not to affect the sintering of zirconia, the sintering process used in this patent cannot ensure complete conversion. Therefore, the hardness, wear resistance and corrosion resistance of the final composite ceramic microspheres cannot reach the ideal effect. In Comparative Example 5, no silicon carbide powder was added for compounding. The alumina-zirconia composite ceramic microspheres have a higher density and qualified wear resistance, but their hardness is very low and their corrosion resistance is poor.

[0103] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of zirconia composite ceramic microspheres, characterized in that: Including, Mix yttria-stabilized tetragonal zirconia, alumina, silicon carbide composite powder and water, and grind to obtain a slurry; the mass ratio of yttria-stabilized tetragonal zirconia to silicon carbide composite powder is (80-90):(5-10); Spray granulate the obtained slurry to form spherical particles; Adopt the form of ball rolling molding to form a spherical green body from the spherical particles and glue; Sinter the spherical green body to obtain yttria-stabilized zirconia composite ceramic microspheres; The silicon carbide composite powder is made of silicon carbide powders with α hexagonal structure and β cubic structure respectively, and the mass ratio of the two is (20-25):(70-78); the silicon carbide composite powder is formed by compounding type A silicon carbide, type B silicon carbide and type C silicon carbide. Among them, the crystal form of the type A silicon carbide is α hexagonal structure, the median particle size is 0.6-0.8 μm, and its mass accounts for 20%-25% of the total weight of the silicon carbide composite powder; the crystal form of the type B silicon carbide is β cubic structure, the median particle size is 0.3-0.5 μm, and its mass accounts for 65%-75% of the total weight of the silicon carbide composite powder; the crystal form of the type C silicon carbide is β cubic structure, the median particle size is 50-90nm, and its mass accounts for 5%-10% of the total weight of the silicon carbide composite powder.

2. The preparation method of the zirconia composite ceramic microbeads according to claim 1, characterized in that: The preparation method of the silicon carbide composite powder includes the following steps: Disperse the powders of type A silicon carbide, type B silicon carbide and type C silicon carbide in ethanol to form a slurry with a solid content of 50%, put it into a drum mixer and stir at 50-100 rpm for 2-3 h, and dry to obtain the silicon carbide composite powder, and the solid content is in terms of mass percentage.

3. The preparation method of the zirconia composite ceramic microbeads according to claim 1, characterized in that: The mass ratio of yttria-stabilized tetragonal zirconia to alumina is (80-90):(5-10).

4. The preparation method of the zirconia composite ceramic microspheres according to claim 1, characterized in that: The median particle size of the yttria-stabilized tetragonal zirconia is 0.2-0.6 μm, and the median particle size of the alumina is 0.3-0.8 μm.

5. The preparation method of the zirconia composite ceramic microbeads according to claim 1, characterized in that: The median particle size of the slurry is less than 0.5 μm and the solid content is 40%-60%, and the solid content is in terms of mass percentage.

6. The preparation method of the zirconia composite ceramic microbeads according to claim 1, characterized in that: Perform spray granulation at a rotation speed of 9000-10000 rpm, an inlet temperature of 200-250 °C, and an outlet temperature of 100-120 °C.

7. The preparation method of the zirconia composite ceramic microbeads according to claim 1, characterized in that: The sintering is carried out at a temperature of 1520-1600 °C for 1-3 h.

8. The preparation method of the zirconia composite ceramic microbeads according to claim 1, wherein, A polishing operation is also included after the sintering is completed.

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