A composite rare earth oxide co-stabilized zirconia ceramic microsphere and its preparation method

Abstract

This invention discloses a composite rare earth oxide co-stabilized zirconia ceramic microsphere and its preparation method, belonging to the technical field of zirconia ceramic microspheres. The zirconia ceramic microspheres are prepared from 80-90 parts by mass of tetragonal zirconia (ZrO2) powder, 0.5-1 parts by mass of alumina (Al2O3) powder, 5-10 parts by mass of yttrium oxide (Y2O3) powder, and 5-10 parts by mass of composite rare earth oxide powder. This invention uses tetragonal zirconia as the base material, adds yttrium oxide (Y2O3) as a stabilizer, and further adds composite rare earth oxides ytterbium oxide (Yb2O3) and nano-gadolinium oxide (Gd2O3). Yb2O3 serves as the second stabilizer, while Gd2O3 enhances the ferroelastic toughening effect of the ceramic. The combined effect of the two rare earth oxides increases the strength of the zirconia ceramic microspheres.

Description

Technical Field

[0001] This invention relates to the field of zirconia ceramic microspheres, and particularly to a composite rare earth oxide co-stabilized zirconia ceramic microsphere and its preparation method. Background Technology

[0002] Ultrafine grinding equipment is widely used in new energy battery materials, paints, coatings, and other fields. It pulverizes materials through complex movements such as mutual impact and compression of the grinding media. The selection of grinding media is crucial in the use of ultrafine grinding equipment, as it determines the cost, efficiency, and quality of the pulverized product. Common grinding media on the market include glass beads, zirconium silicate beads, steel balls, alumina beads, and zirconia beads. Steel balls are less commonly used due to their poor corrosion and wear resistance; glass beads have low strength, high wear, and easily contaminate materials; ordinary ceramic grinding media (main crystalline phases are aluminosilicates and glass phases) produce coarse grains and have poor performance, limiting their use to low-end applications; alumina ceramic grinding media (main crystalline phase is α-alumina) are mainly used for grinding hard mineral materials, but alumina has low fracture toughness and poor wear resistance, making it unsuitable for high-speed sand mills; tetragonal zirconia has a high specific gravity and good overall performance, classifying it as a high-end grinding material.

[0003] The high fracture toughness of tetragonal polycrystalline zirconia (TZP) is mainly attributed to the martensitic phase transformation from tetragonal (t) to monoclinic (m). The constraint on the t→m phase transformation and the stress release during crack propagation greatly improve the material's toughness. Yttrium oxide (Y₂O₃) is often used as a stabilizer for TZP, allowing the tetragonal structure at high temperatures to be retained to room temperature and exert a toughening effect. However, this yttrium-stabilized zirconia ceramic material also has significant drawbacks. During long-term use in the mid-to-low temperature range above 100 °C, a spontaneous transformation from tetragonal to monoclinic phase occurs, leading to a significant decrease in performance and even catastrophic failure, a phenomenon known as "low-temperature aging." Therefore, further doping with other metal ions is necessary to control the lattice size and tetragonality of yttrium-stabilized zirconia ceramics, helping to maintain its structure in a highly tough tetragonal phase. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides composite rare earth oxide co-stabilized zirconia ceramic microspheres and their preparation method.

[0005] As one aspect of the present invention, the present invention provides a method for preparing composite rare earth oxide co-stabilized zirconia ceramic microspheres, which includes the following steps: mixing 80-90 parts by weight of tetragonal zirconia powder, 0.5-1 parts by weight of alumina powder, 5-10 parts by weight of yttrium oxide powder, 5-10 parts by weight of composite rare earth oxide powder and 100 parts by weight of water and grinding them to obtain a slurry; spray granulating the slurry to form spherical particles; forming spherical green bodies with adhesive using a ball-forming method; and sintering the spherical green bodies to obtain zirconia composite ceramic microspheres.

[0006] The composite rare earth oxide powder includes nano-ytterbium oxide and nano-gadolinium oxide, and the mass ratio of nano-ytterbium oxide to nano-gadolinium oxide is (6~7):(3~4).

[0007] Preferably, the median particle size of the tetragonal zirconium oxide powder is 0.2~0.6 μm, the median particle size of the alumina powder is 0.3~0.8 μm, and the median particle size of the yttrium oxide powder is 0.1~0.2 μm.

[0008] Preferably, the median particle size of the nano-ytterbium oxide powder is 50 nm, and the median particle size of the nano-gadolinium oxide powder is 40~60 nm.

[0009] Preferably, the preparation method of the composite rare earth oxide powder is as follows:

[0010] Nano-ytterbium oxide powder and nano-gadolinium oxide powder were dispersed in ethanol to prepare a slurry with a solid content of 50%. The slurry was then placed in a drum mixer and stirred at 50-100 rpm for 1 hour. Finally, it was dried in an 80-degree oven to obtain composite rare earth oxide powder.

[0011] Preferably, the median particle size of the slurry is less than 0.5 μm and the solid content is 40%~60%.

[0012] Preferably, spray granulation is performed at a rotation speed of 9000~10000 rpm, an inlet temperature of 200~250 ℃, and an outlet temperature of 100~120 ℃.

[0013] Preferably, the sintering is carried out at a temperature of 1400~1450 ℃ for 1~3 h.

[0014] Preferably, a polishing operation is also included after sintering.

[0015] This invention provides composite rare earth oxide co-stabilized zirconia ceramic microspheres, prepared from 80-90 parts by mass of tetragonal zirconia (ZrO2) powder, 0.5-1 parts by mass of alumina (Al2O3) powder, 5-10 parts by mass of yttrium oxide (Y2O3) powder, and 5-10 parts by mass of composite rare earth oxide powder. The Yb in the yttrium oxide... 3+The ion's ionic radius is closest to the size of the octahedral interstitial space in zirconium oxide among all rare earth elements, thus inferring the value of Yb. 3+ Ions have a good stabilizing effect on yttrium-stabilized zirconia ceramics. Therefore, by simultaneously adding a second stabilizer, Yb₂O₃, to yttrium-stabilized zirconia, the properties of yttrium-stabilized zirconia ceramics can be adjusted, the aging phenomenon of zirconia can be suppressed, and zirconia ceramic materials with superior performance compared to those with a single stabilizer can be obtained.

[0016] According to relevant research reports, partially stabilized tetragonal zirconia exhibits significantly higher toughness than fully stabilized cubic zirconia with the same stabilizer. The increased toughness may be due to an ferritic toughening mechanism. The ferritic toughening mechanism is related to... This is related to the increased toughness due to the energy absorption caused by the orientation of ferroelastic domains. Numerous experiments have shown that the substitution of Y- by larger-radius trivalent ions... 3+ Both are beneficial for improving the tetragonality of ZrO2, thereby enhancing the toughening effect of ferrite. 3+ The radius is greater than Y 3+ and Yb 3+ Doping with large-radius ions is beneficial The stability of the material is improved. Furthermore, the larger the radius of the dopant ion, the higher the tetragonality of the material lattice, the more pronounced the ferroelastic toughening effect, and the higher the fracture toughness of the material. Therefore, doping yttrium-stabilized zirconia ceramics with Gd₂O₃ can effectively enhance the ferroelastic toughening effect and improve its strength.

[0017] In this invention, when grinding the tetragonal zirconium oxide powder, alumina powder, yttrium oxide powder, composite rare earth oxide powder and water, a certain proportion of dispersant can be added. This is a conventional operation in the field. The type of dispersant does not need to be strictly limited and can be sodium polyacrylate, ammonium polyacrylate, etc. The amount added can be 0.1% to 0.5% of the total mass of the slurry.

[0018] Furthermore, the median particle size of the slurry is less than 0.5 μm and the solid content is 40%~60%.

[0019] Compared with the prior art, the technical inventive points of this invention are as follows:

[0020] The addition of a second stabilizer, Yb2O3, further enhances the stability of the tetragonal phase in yttrium-stabilized zirconia ceramics, thereby increasing the strength of the zirconia ceramic microspheres.

[0021] The addition of Gd2O3, which has a larger cation radius, enhances the ferroelastic toughening mechanism of yttrium-stabilized zirconia ceramics, thereby improving the strength of zirconia ceramic microspheres. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A flowchart illustrating the preparation method of the zirconia ceramic microspheres of the present invention is shown;

[0024] Figure 2 A photograph of the zirconia ceramic microspheres prepared in Example 1 of the present invention is shown.

[0025] Figure 3 The image shown is a SEM image of the zirconia ceramic microspheres prepared in Example 1 of the present invention;

[0026] Figure 4 The image shown is a SEM image of the zirconia ceramic microspheres prepared in Example 2 of the present invention;

[0027] Figure 5 The image shown is a SEM image of the zirconia ceramic microspheres prepared in Example 3 of the present invention. Detailed Implementation

[0028] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0029] All raw materials used in this invention are common in the field, and those skilled in the art can directly purchase them from the market or prepare the same / similar raw materials themselves.

[0030] 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.

[0031] Example 1: A method for preparing composite rare earth oxide co-stabilized zirconia ceramic microspheres, the steps of which are as follows:

[0032] S1. Ingredients: Weigh 85 kg tetragonal zirconium oxide powder, 1 kg alumina powder, 6 kg yttrium oxide powder, 8 kg composite rare earth oxide powder, and 100 kg water;

[0033] S2. Ball milling pulp preparation: Tetragonal zirconium oxide powder, alumina powder, yttrium oxide powder, composite rare earth oxide powder and water are mixed and added to a ball mill jar for ball milling to obtain a slurry with a median particle size of 0.4 μm and a solid content of 50%.

[0034] 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 particles with a diameter of 50 μm with good flowability.

[0035] S4. Ball forming: Spray spherical particles and glue into the ball forming machine to form a spherical green body with a diameter of 1 mm;

[0036] S5. High-temperature sintering: Transfer the spherical green billet to an automated kiln at 1450 ℃ and hold for 2 h to obtain the coarse material;

[0037] S6. Surface polishing: Polishing the surface of the rough material to reduce its surface roughness.

[0038] The preparation method of the composite rare earth oxide powder is as follows: 5.6 kg of nano ytterbium oxide (Yb2O3) powder and 2.4 kg of nano gadolinium oxide (Gd2O3) powder are dispersed in ethanol to form a slurry with a solid content of 50%, which is then placed in a drum mixer and stirred at 50-100 rpm for 1 h, and then dried in an oven at 80℃.

[0039] Example 2: A method for preparing composite rare earth oxide co-stabilized zirconia ceramic microspheres, the steps of which are as follows:

[0040] S1. Ingredients: Weigh 85 kg tetragonal zirconium oxide powder, 1 kg alumina powder, 6 kg yttrium oxide powder, 8 kg composite rare earth oxide powder, and 100 kg water;

[0041] S2. Ball milling pulp preparation: Tetragonal zirconium oxide powder, alumina powder, yttrium oxide powder, composite rare earth oxide powder and water are mixed and added to a ball mill jar for ball milling to obtain a slurry with a median particle size of 0.4 μm and a solid content of 50%.

[0042] 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 particles with a diameter of 50 μm with good flowability.

[0043] S4. Ball forming: Spray spherical particles and glue into the ball forming machine to form a spherical green body with a diameter of 1 mm;

[0044] S5. High-temperature sintering: Transfer the spherical green billet to an automated kiln at 1450 ℃ and hold for 2 h to obtain the coarse material;

[0045] S6. Surface polishing: Polishing the surface of the rough material.

[0046] The preparation method of the composite rare earth oxide powder is as follows: 4.8 kg of nano ytterbium oxide (Yb2O3) powder and 3.2 kg of nano gadolinium oxide (Gd2O3) powder are dispersed in ethanol to form a slurry with a solid content of 50%, which is then placed in a drum mixer and stirred at 50-100 rpm for 1 h, and then dried in an 80-degree oven.

[0047] Example 3: A method for preparing composite rare earth oxide co-stabilized zirconia ceramic microspheres, the steps of which are as follows:

[0048] S1. Ingredients: Weigh 84.5 kg tetragonal zirconium oxide powder, 0.5 kg alumina powder, 5 kg yttrium oxide powder, 10 kg composite rare earth oxide powder, and 100 kg water;

[0049] S2. Ball milling pulp preparation: Tetragonal zirconium oxide powder, alumina powder, yttrium oxide powder, composite rare earth oxide powder and water are mixed and added to a ball mill jar for ball milling to obtain a slurry with a median particle size of 0.4 μm and a solid content of 50%.

[0050] 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 particles with a diameter of 50 μm with good flowability.

[0051] S4. Ball forming: Spray spherical particles and glue into the ball forming machine to form a spherical green body with a diameter of 1 mm;

[0052] S5. High-temperature sintering: Transfer the spherical green billet to an automated kiln at 1400 ℃ and hold for 2 h to obtain the coarse material;

[0053] S6. Surface polishing: Polishing the surface of the rough material.

[0054] The preparation method of the composite rare earth oxide powder is as follows: 6.5 kg of nano ytterbium oxide (Yb2O3) powder and 3.5 kg of nano gadolinium oxide (Gd2O3) powder are dispersed in ethanol to form a slurry with a solid content of 50%, which is then placed in a drum mixer and stirred at 50-100 rpm for 1 h, and then dried in an 80-degree oven.

[0055] Example 4: A method for preparing composite rare earth oxide co-stabilized zirconia ceramic microspheres, which is basically the same as that in Example 1, except that:

[0056] S1. The ingredients are changed to weigh 85 kg tetragonal zirconium oxide powder, 1 kg alumina powder, 8 kg yttrium oxide powder, 6 kg composite rare earth oxide powder, and 100 kg water;

[0057] The preparation method of the composite rare earth oxide powder is as follows: 4.2 kg of nano ytterbium oxide (Yb2O3) powder and 1.8 kg of nano gadolinium oxide (Gd2O3) powder are dispersed in ethanol to form a slurry with a solid content of 50%, which is then placed in a drum mixer and stirred at 50-100 rpm for 1 h, and then dried in an 80-degree oven.

[0058] Comparative Example 1: A method for preparing composite rare earth oxide co-stabilized zirconia ceramic microspheres is basically the same as that in Example 1, except that 5.6 kg of nano ytterbium oxide (Yb2O3) powder and 2.4 kg of nano gadolinium oxide (Gd2O3) powder are directly replaced by 8 kg of nano ytterbium oxide (Yb2O3) powder.

[0059] Comparative Example 2: A method for preparing composite rare earth oxide co-stabilized zirconia ceramic microspheres is basically the same as that in Example 1, except that 5.6 kg of nano ytterbium oxide (Yb2O3) powder and 2.4 kg of nano gadolinium oxide (Gd2O3) powder are directly replaced by 8 kg of nano gadolinium oxide (Gd2O3) powder.

[0060] Comparative Example 3: A method for preparing composite rare earth oxide co-stabilized zirconia ceramic microspheres is basically the same as that in Example 1, except that:

[0061] S1. The ingredients are changed to weigh 87 kg tetragonal zirconium oxide powder, 1 kg alumina powder, 10 kg yttrium oxide powder, 2 kg composite rare earth oxide powder, and 100 kg water;

[0062] The preparation method of the composite rare earth oxide powder is as follows: 1.4 kg of nano ytterbium oxide (Yb2O3) powder and 0.6 kg of nano gadolinium oxide (Gd2O3) powder are dispersed in ethanol to form a slurry with a solid content of 50%, which is then placed in a drum mixer and stirred at 50-100 rpm for 1 h, and then dried in an 80-degree oven.

[0063] Comparative Example 4: A method for preparing yttrium-stabilized zirconia ceramic microspheres, which is basically the same as that in Example 1, except that:

[0064] Instead of adding composite rare earth oxide powder and S1, the ingredients are changed to 93 kg tetragonal zirconium oxide powder, 1 kg alumina powder, 6 kg yttrium oxide powder, and 100 kg water.

[0065] Comparative Example 5: A method for preparing composite rare earth oxide co-stabilized zirconia ceramic microspheres, which is basically the same as that in Example 1, except that:

[0066] S1. The ingredients are changed to weigh 85 kg tetragonal zirconium oxide powder, 1 kg alumina powder, 10 kg yttrium oxide powder, 4 kg composite rare earth oxide powder, and 100 kg water;

[0067] The preparation method of the composite rare earth oxide powder is as follows: 2.8 kg of nano ytterbium oxide (Yb2O3) powder and 1.2 kg of nano gadolinium oxide (Gd2O3) powder are dispersed in ethanol to form a slurry with a solid content of 50%, which is then placed in a drum mixer and stirred at 50-100 rpm for 1 h, and then dried in an 80-degree oven.

[0068] Comparative Example 6: A method for preparing composite rare earth oxide co-stabilized zirconia ceramic microspheres, which is basically the same as that in Example 1, except that:

[0069] S1. The ingredients are changed to weigh 79 kg tetragonal zirconium oxide powder, 1 kg alumina powder, 8 kg yttrium oxide powder, 12 kg composite rare earth oxide powder, and 100 kg water;

[0070] The preparation method of the composite rare earth oxide powder is as follows: 8.4 kg of nano ytterbium oxide (Yb2O3) powder and 3.6 kg of nano gadolinium oxide (Gd2O3) powder are dispersed in ethanol to form a slurry with a solid content of 50%, which is then placed in a drum mixer and stirred at 50-100 rpm for 1 h, and then dried in an 80-degree oven.

[0071] Comparative Example 7: A method for preparing composite rare earth oxide co-stabilized zirconia ceramic microspheres, which is basically the same as that in Example 1, except that:

[0072] S1. The ingredients are changed to weigh 78 kg tetragonal zirconium oxide powder, 1 kg alumina powder, 5 kg yttrium oxide powder, 16 kg composite rare earth oxide powder, and 100 kg water;

[0073] The preparation method of the composite rare earth oxide powder is as follows: 11.2 kg of nano ytterbium oxide (Yb2O3) powder and 4.8 kg of nano gadolinium oxide (Gd2O3) powder are dispersed in ethanol to form a slurry with a solid content of 50%, which is then placed in a drum mixer and stirred at 50-100 rpm for 1 h, and then dried in an 80-degree oven.

[0074] The density, hardness, and self-wear of the zirconia composite ceramic microspheres prepared in all examples and comparative examples were tested according to the standard JC / T 2136-2012 "Microcrystalline Zirconia Grinding Media Balls". They were used for grinding high-purity zirconium carbide powder, and the final zirconium oxide content introduced by the grinding process was measured, which is the wear amount. The crushing strength of the zirconia composite ceramic microspheres prepared in all examples and comparative examples was tested using a crushing strength tester. These results are shown in Table 1.

[0075] Table 1 Test results of zirconia composite ceramic microspheres

[0076] ,

[0077] As can be seen from the test results in Table 1, the composite rare earth oxide co-stabilized zirconia composite ceramic microspheres prepared in Examples 1-4 of this invention have higher Vickers hardness, lower self-wear, lower wear amount, and higher crushing strength. This is because the addition of an appropriate amount of composite rare earth oxides can effectively improve the stability and strength of yttrium-stabilized zirconia ceramics. The properties of Comparative Examples 1-3 are all lower than those of Examples 1-4. Comparative Example 1 did not add gadolinium oxide, lacking the ferroelastic toughening mechanism, resulting in insufficient strength of the ceramic microspheres. Comparative Example 2 did not add ytterbium oxide, lacking the second stabilizer effect, also resulting in insufficient strength of the ceramic microspheres. Comparative Examples 3 and 5 have insufficient overall addition of composite rare earth oxides, and the reinforcing effect of the two rare earth oxides is not obvious. Comparative Example 4 is a common yttrium-stabilized zirconia ceramic microsphere, which has low strength and poor stability, thus exhibiting the worst overall performance. Comparative Examples 6 and 7 have excessive overall addition of composite rare earth oxides. Excessive addition will affect the strength of the composite ceramic microspheres, resulting in lower crushing strength and decreased wear resistance.

[0078] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention 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 substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing composite rare earth oxide co-stabilized zirconia ceramic microspheres, characterized in that: Includes the following steps, Mix 80-90 parts by weight of tetragonal zirconium oxide powder, 0.5-1 parts by weight of alumina powder, 5-10 parts by weight of yttrium oxide powder, 5-10 parts by weight of composite rare earth oxide powder and 100 parts by weight of water and grind them 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 glue. Sintering spherical green bodies yields zirconia composite ceramic microspheres; The composite rare earth oxide powder comprises nano-ytterbium oxide and nano-gadolinium oxide, wherein the mass ratio of nano-ytterbium oxide to nano-gadolinium oxide is (6~7):(3~4), the median particle size of the nano-ytterbium oxide powder is 50 nm, and the median particle size of the nano-gadolinium oxide powder is 40~60 nm. The preparation method of the composite rare earth oxide powder is as follows: Nano-ytterbium oxide powder and nano-gadolinium oxide powder were dispersed in ethanol to prepare a slurry with a solid content of 50%. The slurry was then placed in a drum mixer and stirred at 50-100 rpm for 1 hour. Finally, it was dried in an 80-degree oven to obtain composite rare earth oxide powder.

2. The method for preparing composite rare earth oxide co-stabilized zirconia ceramic microspheres according to claim 1, characterized in that: The median particle size of the tetragonal zirconium oxide powder is 0.2~0.6 μm, the median particle size of the alumina powder is 0.3~0.8 μm, and the median particle size of the yttrium oxide powder is 0.1~0.2 μm.

3. The method for preparing composite rare earth oxide co-stabilized zirconia ceramic microspheres according to claim 1, characterized in that: The slurry has a median particle size of less than 0.5 μm and a solid content of 40% to 60%.

4. The method for preparing composite rare earth oxide co-stabilized zirconia ceramic microspheres according to claim 1, 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 ℃.

5. The method for preparing composite rare earth oxide co-stabilized zirconia ceramic microspheres according to claim 1, characterized in that: The sintering process is carried out at a temperature of 1400~1450 ℃ for 1~3 h.

6. The method for preparing composite rare earth oxide co-stabilized zirconia ceramic microspheres according to claim 5, characterized in that: Polishing is also included after sintering.

7. Composite rare earth oxide co-stabilized zirconia ceramic microspheres obtained by any of the preparation methods described in claims 1-6.

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