High-sphericity yttrium oxide granulated powder and preparation method thereof
By mixing dispersant with deionized water, ball milling, and secondary spray granulation, combined with the use of planetary ball mills and horizontal ball mills, the problem of poor sphericity of yttrium oxide granulated powder was solved, and high sphericity yttrium oxide granulated powder was prepared, improving the flowability and density of the powder and avoiding cracking during green body forming.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SUZHOU DREAMCHASING ELECTRONIC MATERIALS CO LTD
- Filing Date
- 2026-04-13
- Publication Date
- 2026-06-09
AI Technical Summary
Existing spray granulation processes produce yttrium oxide granules with poor sphericity, affecting the powder's flowability and loose packing density, which makes it prone to cracking during green body forming.
A dispersant was mixed with deionized water, and ball milling and spray granulation were performed. The amount of dispersant and binder added was controlled. The particle morphology was optimized through a secondary spray granulation process. The particles were then refined using a planetary ball mill and a horizontal ball mill, combined with degreasing treatment, to prepare yttrium oxide granulated powder with high sphericity.
It significantly improved the sphericity of yttrium oxide granulated powder, improved the powder's flowability and density, avoided cracking problems during green body forming, and enhanced the strength and density of the green body.
Smart Images
Figure CN122166814A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of yttrium oxide granulation powder preparation, specifically to a high sphericity yttrium oxide granulation powder and its preparation method. Background Technology
[0002] Yttrium oxide, as an important rare earth oxide, has excellent properties such as high melting point and strong corrosion resistance, and is widely used in high-tech fields such as electronic semiconductors, aerospace, and laser materials.
[0003] Spherical yttrium oxide particles can significantly improve the strength and density of green bodies, thereby optimizing the final properties of yttrium oxide sintered ceramics. Existing spray granulation methods have become the mainstream granulation process due to their simplicity and ease of large-scale production. However, the resulting yttrium oxide granules have poor sphericity, with most particles being apple-shaped or boat-shaped. This severely affects the powder's flowability and loose-pack density, leading to cracking during green body forming and limiting its capabilities in high-precision applications. Summary of the Invention
[0004] The present invention aims to solve the above-mentioned technical problem, namely, that the sphericity of yttrium oxide granulated powder produced by the existing spray granulation process is poor, which affects the flowability and loose packing density of the powder, and thus leads to the problem of easy cracking during green body forming.
[0005] In a first aspect, the present invention provides a method for preparing yttrium oxide granulated powder with high sphericity, comprising the following steps:
[0006] S1, mix the dispersant with deionized water, add yttrium oxide powder to prepare a slurry with a solid content of 30%-45%, and ball mill the slurry so that the D50 particle size of the yttrium oxide powder in the slurry reaches 0.2-0.5μm; S2, the obtained slurry is subjected to a first spray granulation to obtain spherical yttrium oxide granulated powder; S3, degrease spherical yttrium oxide granules to obtain additive-free intermediate powder; S4. Mix the dispersant with deionized water and add the intermediate powder obtained in S3 to prepare a slurry with a solid content of 40%-50%. Ball mill the slurry to make the D50 particle size of the yttrium oxide powder in the slurry reach 0.5-1.5μm. S5, add binder and defoamer to the slurry obtained in S4, and stir; S6. The slurry obtained from S5 is subjected to a second spray granulation to obtain yttrium oxide granulated powder with high sphericity.
[0007] The reasons for not adding a binder to the horizontal ball mill in this application include: First, the binder will react with the dispersant, and adding the binder too early will affect the dispersion and fineness of the powder; second, the binder is prone to generating foam, especially in the high-speed impact environment of the ball mill jar, where foam will seriously affect the spheroidization of the powder, resulting in hollow or apple-shaped granules. Although defoamers are added to reduce foam generation, the content of defoamers should not be too high. Therefore, adding the binder during stirring can control the foam content.
[0008] In the preferred embodiment of the above-mentioned method for preparing high sphericity yttrium oxide granulated powder, in S1 and S4, the dispersant is one or more of ammonium polyacrylate, polyethylene glycol, and sodium citrate, and the addition amount is 0.5-1wt%.
[0009] It should be noted that during the first and second ball milling of the slurry, the powder disperses more uniformly under the action of the dispersant, exhibiting better flowability and finer particles. Appropriate dispersant dosage greatly aids the ball milling process. Too little dispersant affects the dispersibility between powders, leading to excessively high slurry viscosity and causing blockage of the atomizing disc and feed pipe during granulation. Too much dispersant affects the bonding effect between powders, further impacting the shape of the granulated powder and promoting the formation of apple-shaped particles. In this application, by setting the dispersant dosage to 0.5-1 wt% of the total powder weight, the dispersion effect of the powder and the bonding performance of the particles can be effectively balanced. This avoids both the problem of excessively high slurry viscosity and blockage of the granulation equipment due to insufficient dispersant, and the situation where excessive dispersant produces apple-shaped particles and affects sphericity.
[0010] In the preferred embodiment of the above-mentioned method for preparing high sphericity yttrium oxide granulated powder, in S1, ball milling is carried out in a planetary ball mill, the rotation speed of the planetary ball mill is 200-300 rpm, and the ball milling time is 6-8 h.
[0011] In the preferred embodiment of the above-mentioned method for preparing high sphericity yttrium oxide granulated powder, in S1, the ratio of yttrium oxide powder to milling beads is 1:1-1.5, and a combination of 0.3-0.8 mm milling beads is selected for milling.
[0012] In the preferred technical scheme of the above-mentioned method for preparing high sphericity yttrium oxide granulated powder, in S3, the degreasing treatment is carried out in a 99.5% high-purity alumina crucible, the degreasing temperature is increased from 20-40℃ / h to 600-800℃, held for 6-24h and then cooled to room temperature with the furnace.
[0013] In the preferred embodiment of the above-mentioned method for preparing high sphericity yttrium oxide granulated powder, in step S4, ball milling is carried out in a horizontal ball mill, the rotation speed of the horizontal ball mill is 120-160 rpm, and the ball milling time is 12-36 h.
[0014] In the preferred technical scheme of the above-mentioned method for preparing high sphericity yttrium oxide granulated powder, in S4, the ratio of yttrium oxide powder to milling beads is 1:1.5-3, and a combination of 1-15mm milling beads is selected for milling.
[0015] In the preferred embodiment of the above-mentioned method for preparing high sphericity yttrium oxide granulated powder, the binder is one or more of polyethylene glycol, polyvinyl alcohol, and sodium carboxymethyl cellulose, and the amount of binder added is 1-1.5 wt%; the defoamer is one or more of n-butanol, n-pentanol, and organosilicon, and the amount of defoamer added is 0.5-1 wt%.
[0016] It should be noted that the binder content is a crucial factor affecting the sphericity of the granulated powder. A low binder content results in poor adhesion between powder particles, making granulation difficult and leading to low green strength. Conversely, a high binder content results in an excessively thick binder shell on the surface of the droplets during drying, hindering gas evaporation and causing a continuous increase in gas pressure. Eventually, the gas escapes through weak points in the shell, forming apple-shaped particles. This application effectively reduces foam formation in the slurry and ensures the sphericity of the yttrium oxide granulated powder by controlling the binder addition to 1-1.5 wt% of the total powder weight and the defoamer addition to 0.5-1 wt% of the total powder weight.
[0017] In the preferred technical scheme of the above-mentioned method for preparing high sphericity yttrium oxide granulated powder, the process parameters of the first spray granulation and the second spray granulation are the same, both controlled at: inlet air temperature 170-240℃, outlet air temperature 90-120℃, atomizer speed 10000-15000rpm, and fan speed 23-35Hz.
[0018] In a second aspect, the present invention also provides a high sphericity yttrium oxide granulated powder, which is prepared by the above-described preparation method.
[0019] The beneficial effects of this invention are that the method for preparing high sphericity yttrium oxide granulated powder of this application can effectively balance the dispersion effect of powder and the adhesion performance of particles by controlling the amount of dispersant added. By precisely controlling the addition ratio of binder and defoamer, the generation of foam in slurry can be significantly suppressed. By adopting a secondary spray granulation process, the morphology and structure of particles are further optimized, effectively avoiding problems such as molding difficulties or apple-shaped particles caused by improper binder content. Attached Figure Description
[0020] Figure 1SEM images of yttrium oxide granulated powder prepared by traditional methods; Figure 2 SEM image of the yttrium oxide granulated powder with high sphericity prepared by the method of this application; Figure 3 A schematic diagram illustrating the average sphericity of yttrium oxide granulated powder prepared by traditional methods; Figure 4 This is a schematic diagram illustrating the average sphericity of the yttrium oxide granulated powder prepared by the method of this application; Detailed Implementation Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.
[0021] It should be noted that in the description of this invention, terms such as "upper," "lower," "left," "right," "front," and "rear," which indicate direction or positional relationships, are based on the direction or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0022] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly, for example, referring to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0023] Example 1: The method for preparing high-sphericity yttrium oxide granulated powder of the present invention includes the following steps: S1, 0.8wt% ammonium polyacrylate as a dispersant was mixed with deionized water and stirred to obtain a mixture. Yttrium oxide powder was added to the mixture to obtain a slurry with a solid content of 40%. The slurry was then fed into a planetary ball mill for ball milling at a speed of 250 rpm for 7 hours. The ratio of yttrium oxide powder to grinding beads was 1:1.2, and the size of the grinding beads was 0.5 mm. The D50 particle size of the yttrium oxide powder in the slurry was 0.35 μm. The obtained slurry was then transferred to a mixing tank and stirred at a speed of 160-300 rpm.
[0024] S2, the slurry obtained in S1 is subjected to first spray granulation to obtain spherical yttrium oxide granulated powder; the process parameters for the first spray granulation are: inlet air temperature 200℃, outlet air temperature 110℃, atomizer speed 12000rpm, and fan speed 30Hz.
[0025] S3. The spherical yttrium oxide granules obtained in S2 are placed in a 99.5% high-purity alumina crucible for degreasing to obtain intermediate powder without any additives. The degreasing parameters are: heating to 700℃ at 30℃ / h, holding at 700℃ for 12h, and then naturally cooling to room temperature.
[0026] S4. 0.8wt% ammonium polyacrylate was mixed with deionized water as a dispersant and stirred to obtain a mixture. Yttrium oxide powder was added to the mixture to obtain a slurry with a solid content of 45%. The slurry was then fed into a horizontal ball mill for ball milling at a speed of 140 rpm for 24 hours. The ratio of yttrium oxide powder to milling beads was 1:2, and the size of the milling beads was 5 mm. The D50 particle size of the yttrium oxide powder in the slurry was 1.2 μm.
[0027] S5, add binder and defoamer to the slurry obtained in S4, and then stir and mix it evenly; the binder is polyethylene glycol, and the amount added is 1.2wt%; the defoamer is n-butanol, and the amount added is 0.8wt%.
[0028] S6. The slurry obtained in S5 is subjected to a second spray granulation to obtain yttrium oxide granulated powder with high sphericity. The parameters for the second spray granulation are: inlet air temperature 200℃, outlet air temperature 110℃, atomizer speed 12000rpm, and fan speed 30Hz.
[0029] Example 2: The method for preparing high-sphericity yttrium oxide granulated powder of the present invention includes the following steps: S1, 1wt% sodium citrate was mixed with deionized water as a dispersant and stirred to obtain a mixture. Yttrium oxide powder was added to the mixture to obtain a slurry with a solid content of 45%. The slurry was added to a planetary ball mill for ball milling at a speed of 300 rpm for 8 hours. The ratio of yttrium oxide powder to grinding beads was 1:1.5, and the size of the grinding beads was 0.8 mm. The D50 particle size of the yttrium oxide powder in the slurry was 0.45 μm. The obtained slurry was transferred to a mixing tank and stirred at a speed of 160-300 rpm.
[0030] S2, the slurry obtained in S1 is subjected to first spray granulation to obtain spherical yttrium oxide granulated powder; the process parameters for the first spray granulation are: inlet air temperature 190℃, outlet air temperature 105℃, atomizer speed 11000rpm, and fan speed 28Hz.
[0031] S3. The spherical yttrium oxide granules obtained in S2 are placed in a 99.5% high-purity alumina crucible for degreasing to obtain intermediate powder without any additives. The degreasing parameters are: heating to 700℃ at 30℃ / h, holding at 700℃ for 12h, and then naturally cooling to room temperature.
[0032] S4, 1wt% sodium citrate was mixed with deionized water as a dispersant and stirred to obtain a mixture. Yttrium oxide powder was added to the mixture to obtain a slurry with a solid content of 42%. The slurry was added to a horizontal ball mill for ball milling at a speed of 130 rpm for 28 hours. The ratio of yttrium oxide powder to grinding beads was 1:3, and the size of the grinding beads was 10 mm. The D50 particle size of the yttrium oxide powder in the slurry was 1.3 μm.
[0033] S5, add binder and defoamer to the slurry obtained in S4, and then stir and mix it evenly; the binder is polyvinyl alcohol, and the amount added is 1.5wt%; the defoamer is n-pentanol, and the amount added is 0.6wt%.
[0034] S6. The slurry obtained from S5 is subjected to a second spray granulation to obtain yttrium oxide granulated powder with high sphericity. The parameters for the second spray granulation are: inlet air temperature 190℃, outlet air temperature 105℃, atomizer speed 11000rpm, and fan speed 28Hz.
[0035] Example 3: The method for preparing high-sphericity yttrium oxide granulated powder of the present invention includes the following steps: S1, 0.5wt% polyethylene glycol was mixed with deionized water as a dispersant and stirred to obtain a mixture. Yttrium oxide powder was added to the mixture to obtain a slurry with a solid content of 35%. The slurry was then fed into a planetary ball mill for ball milling at a speed of 200 rpm for 6 hours. The ratio of yttrium oxide powder to grinding beads was 1:1, and the size of the grinding beads was 0.3 mm. The D50 particle size of the yttrium oxide powder in the slurry was 0.25 μm. The resulting slurry was then transferred to a mixing tank and stirred at a speed of 160-300 rpm.
[0036] S2, the slurry obtained in S1 is subjected to first spray granulation to obtain spherical yttrium oxide granulated powder; the process parameters for the first spray granulation are: inlet air temperature 240℃, outlet air temperature 120℃, atomizer speed 15000rpm, and fan speed 35Hz.
[0037] S3. The spherical yttrium oxide granules obtained in S2 are placed in a 99.5% high-purity alumina crucible for degreasing to obtain intermediate powder without any additives. The degreasing parameters are: heating to 700℃ at 30℃ / h, holding at 700℃ for 12h, and then naturally cooling to room temperature.
[0038] S4. 0.5wt% polyethylene glycol was mixed with deionized water as a dispersant and stirred to obtain a mixture. Yttrium oxide powder was added to the mixture to obtain a slurry with a solid content of 50%. The slurry was then fed into a horizontal ball mill for ball milling at a speed of 120 rpm for 36 hours. The ratio of yttrium oxide powder to milling beads was 1:1.5, and the size of the milling beads was 15 mm. The D50 particle size of the yttrium oxide powder in the slurry was 1.5 μm.
[0039] S5, add binder and defoamer to the slurry obtained in S4, and then stir and mix it evenly; the binder is sodium carboxymethyl cellulose, and the amount added is 1 wt%; the defoamer is organosilicon, and the amount added is 1 wt%.
[0040] S6. The slurry obtained from S5 is subjected to a second spray granulation to obtain yttrium oxide granulated powder with high sphericity. The parameters for the second spray granulation are: inlet air temperature 240℃, outlet air temperature 120℃, atomizer speed 15000rpm, and fan speed 35Hz.
[0041] Example 4: The difference between this embodiment and Embodiment 1 is that in S3, the degreasing parameters are: heating at 20℃ / h to 600℃, holding at that temperature for 24h, and then naturally cooling to room temperature. All other parameters are the same as in Embodiment 1.
[0042] Example 5: The difference between this embodiment and Embodiment 1 is that: The binder in S5 was replaced with polyvinyl alcohol at an addition amount of 1.5 wt%, and the defoamer remained n-butanol at an addition amount of 0.5 wt%; the remaining parameters were the same as in Example 1.
[0043] Example 6: The method for preparing high-sphericity yttrium oxide granulated powder of the present invention includes the following steps: S1, 0.6wt% sodium citrate was mixed with deionized water as a dispersant and stirred to obtain a mixture. Yttrium oxide powder was added to the mixture to obtain a slurry with a solid content of 42%. The slurry was added to a planetary ball mill for ball milling at a speed of 280 rpm for 7.5 h. The ratio of yttrium oxide powder to grinding beads was 1:1.5, and the size of the grinding beads was 0.6 mm. The D50 particle size of the yttrium oxide powder in the slurry was 0.38 μm. The obtained slurry was transferred to a mixing tank and stirred at a speed of 160-300 rpm.
[0044] S2, the slurry obtained in S1 is subjected to first spray granulation to obtain spherical yttrium oxide granulated powder; the process parameters for the first spray granulation are: inlet air temperature 190℃, outlet air temperature 105℃, atomizer speed 14000rpm, and fan speed 32Hz.
[0045] S3. The spherical yttrium oxide granules obtained in S2 are placed in a 99.5% high-purity alumina crucible for degreasing to obtain intermediate powder without any additives. The degreasing parameters are: heating to 700℃ at 30℃ / h, holding at 700℃ for 12h, and then naturally cooling to room temperature.
[0046] S4. 0.6wt% sodium citrate was mixed with deionized water as a dispersant and stirred to obtain a mixture. Yttrium oxide powder was added to the mixture to obtain a slurry with a solid content of 40%. The slurry was then fed into a horizontal ball mill for ball milling at a speed of 150 rpm for 20 hours. The ratio of yttrium oxide powder to milling beads was 1:2.5, and the size of the milling beads was 10 mm. The D50 particle size of the yttrium oxide powder in the slurry was 1.3 μm.
[0047] S5, add binder and defoamer to the slurry obtained in S4, and then stir and mix it evenly; the binder is polyethylene glycol, and the amount added is 1 wt%; the defoamer is n-pentanol, and the amount added is 0.8 wt%.
[0048] S6. The slurry obtained in S5 is subjected to a second spray granulation to obtain yttrium oxide granulated powder with high sphericity. The parameters for the second spray granulation are: inlet air temperature 190℃, outlet air temperature 105℃, atomizer speed 14000rpm, and fan speed 32Hz.
[0049] Table 1. Detection results of yttrium oxide granulated powder with high sphericity
[0050] From Table 1 and Appendix Figure 1 Appendix Figure 3 It can be seen that the granulated powders produced by traditional yttrium oxide granulation processes are mostly apple-shaped or boat-shaped, with an average sphericity of 0.82. (See Table 1 and Appendix...) Figure 2 Appendix Figure 4 It can be seen that the granulated powder prepared by the high sphericity yttrium oxide granulation method of this application has a highly spherical shape, with an average sphericity of 0.92, which is significantly better than the granulated powder prepared by traditional methods. The six embodiments of this invention solve the problem of poor sphericity of yttrium oxide granulated powder through a secondary granulation method; the innovation lies in the secondary granulation, the selection and addition ratio of the dispersant, and the timing of the addition of the binder and defoamer.
[0051] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.
Claims
1. A method for preparing yttrium oxide granulated powder with high sphericity, characterized in that, Includes the following steps: S1, mix the dispersant with deionized water, add yttrium oxide powder to prepare a slurry with a solid content of 30%-45%, and ball mill the slurry so that the D50 particle size of the yttrium oxide powder in the slurry reaches 0.2-0.5μm; S2, the obtained slurry is subjected to a first spray granulation to obtain spherical yttrium oxide granulated powder; S3, degrease spherical yttrium oxide granules to obtain additive-free intermediate powder; S4. Mix the dispersant with deionized water and add the intermediate powder obtained in S3 to prepare a slurry with a solid content of 40%-50%. Ball mill the slurry to make the D50 particle size of the yttrium oxide powder in the slurry reach 0.5-1.5μm. S5, add binder and defoamer to the slurry obtained in S4, and stir; S6. The slurry obtained from S5 is subjected to a second spray granulation to obtain yttrium oxide granulated powder with high sphericity.
2. The method for preparing high-sphericity yttrium oxide granulated powder according to claim 1, characterized in that: In S1 and S4, the dispersant is one or more of ammonium polyacrylate, polyethylene glycol, and sodium citrate, and the amount added is 0.5-1 wt%.
3. The method for preparing high-sphericity yttrium oxide granulated powder according to claim 1, characterized in that: In S1, ball milling is carried out in a planetary ball mill with a rotation speed of 200-300 rpm and a milling time of 6-8 hours.
4. The method for preparing high-sphericity yttrium oxide granulated powder according to claim 3, characterized in that: In S1, the ratio of yttrium oxide powder to grinding beads is 1:1-1.5, and a combination of 0.3-0.8 mm grinding beads is used for grinding.
5. The method for preparing high-sphericity yttrium oxide granulated powder according to claim 1, characterized in that: In S3, the degreasing process is carried out in a 99.5% high-purity alumina crucible. The degreasing temperature is increased from 20-40℃ / h to 600-800℃, held for 6-24h, and then cooled to room temperature with the furnace.
6. The method for preparing high-sphericity yttrium oxide granulated powder according to claim 1, characterized in that: In S4, ball milling is carried out in a horizontal ball mill with a rotation speed of 120-160 rpm and a milling time of 12-36 h.
7. The method for preparing high-sphericity yttrium oxide granulated powder according to claim 6, characterized in that: In S4, the ratio of yttrium oxide powder to grinding beads is 1:1.5-3, and a combination of 1-15mm grinding beads is used for grinding.
8. The method for preparing high-sphericity yttrium oxide granulated powder according to claim 1, characterized in that: The binder is one or more of polyethylene glycol, polyvinyl alcohol, and sodium carboxymethyl cellulose, and the amount of binder added is 1-1.5 wt%; the defoamer is one or more of n-butanol, n-pentanol, and organosilicon, and the amount of defoamer added is 0.5-1 wt%.
9. The method for preparing high-sphericity yttrium oxide granulated powder according to claim 1, characterized in that: The process parameters for the first and second spray granulation processes are the same, both controlled at: inlet air temperature 170-240℃, outlet air temperature 90-120℃, atomizer speed 10000-15000rpm, and fan speed 23-35Hz.
10. A yttrium oxide granulated powder with high sphericity, characterized in that: It is prepared by the preparation method according to any one of claims 1-9.