Cerium oxide polishing solution and preparation method thereof
By controlling the particle size and distribution of cerium oxide particles and using agitation and sand milling with sodium salts and magnesium aluminum silicate, the problem of poor suspension of cerium oxide polishing slurry was solved, enabling high-precision polishing applications.
Patent Information
- Application Number
- CN202511251203.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-03
- Publication Date
- 2025-11-11
AI Technical Summary
Existing cerium oxide polishing slurries suffer from problems such as large particle size, wide particle size distribution, and poor suspension, which limit their application in the field of high-precision polishing.
A cerium oxide polishing slurry was prepared by mixing cerium oxide particles, sodium salts, and magnesium aluminum silicate in a specific ratio and under specific conditions, followed by sand milling. The particle size and distribution were controlled to improve the suspension.
The prepared cerium oxide polishing slurry has small particle size, narrow distribution, and good suspension, making it suitable for high-precision polishing. It does not exhibit a clear liquid layer at the top or caking at the bottom during long-term storage.
Smart Images
Figure CN120924167A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a cerium oxide polishing slurry and its preparation method. Background Technology
[0002] Cerium oxide possesses excellent chemical activity and moderate particle hardness, resulting in high polishing efficiency and quality. It is widely used in glass substrate materials such as cover glass and optical devices, earning it the reputation of "King of Polishing." Currently, cerium oxide polishing slurries often exhibit problems such as large particle size, wide particle size distribution, easy agglomeration, and poor suspension, severely limiting their application in high-precision polishing. Therefore, there is an urgent need for a cerium oxide polishing slurry with small particle size, narrow particle size distribution, and good suspension. Summary of the Invention
[0003] The purpose of this invention is to provide a method for preparing a cerium oxide polishing slurry, which improves the suspension properties of the slurry. Furthermore, this method improves the dispersibility of cerium oxide particles in the polishing slurry, reduces the particle size of the cerium oxide particles, and results in a narrower particle size distribution. In addition, this invention provides a cerium oxide polishing slurry.
[0004] The present invention achieves the above objectives using the following technical solutions.
[0005] On one hand, the present invention provides a method for preparing a cerium oxide polishing slurry, comprising the following steps:
[0006] (1) Stir 45-75 parts by weight of cerium oxide particles, 0.1-0.6 parts by weight of sodium salts, 0.8-4 parts by weight of magnesium aluminum silicate and water to obtain cerium oxide sand milling slurry; wherein, the sodium salts are selected from one or more of sodium citrate and sodium hexametaphosphate, and the amount of water used is 300-500 mL based on 60 g of cerium oxide particles;
[0007] (2) The cerium oxide sand milling liquid is subjected to sand milling treatment to obtain cerium oxide polishing liquid.
[0008] The amount of cerium oxide particles used is 45 to 75 parts by weight; preferably 55 to 65 parts by weight.
[0009] The amount of sodium salt is 0.1 to 0.6 parts by weight; preferably 0.2 to 0.4 parts by weight.
[0010] The sodium salt is selected from one or more of sodium citrate and sodium hexametaphosphate. In some embodiments, the sodium salt is sodium citrate. In other embodiments, the sodium salt is sodium hexametaphosphate.
[0011] The amount of magnesium aluminum silicate used is 0.8 to 4 parts by weight; preferably 1.5 to 2.5 parts by weight.
[0012] Based on 60g of cerium oxide particles, the amount of water used is 300-500mL; preferably 350-450mL.
[0013] By controlling the above materials within the dosage range shown above, the suspension of cerium oxide polishing slurry and the dispersibility of cerium oxide particles in the polishing slurry can be improved, the particle size of cerium oxide particles can be reduced, and the particle size distribution of cerium oxide particles can be narrowed.
[0014] According to the preparation method of the present invention, preferably, the particle size D of the cerium oxide particles is... 50 <5μm. More preferably, the particle size D of the cerium oxide particles is... 50 <2.5 μm. In some embodiments, the cerium oxide particles have a particle size of 1 to 2 μm.
[0015] According to the preparation method of the present invention, preferably, the sodium salt is sodium citrate, and the amount of sodium citrate used is 0.3 to 0.5 parts by weight. More preferably, the amount of sodium citrate used is 0.4 to 0.45 parts by weight. This helps to improve the suspension of cerium oxide polishing fluid and the dispersibility of cerium oxide particles in the polishing fluid, reduce the particle size of cerium oxide particles, and help to make the particle size distribution of cerium oxide particles narrower.
[0016] According to the preparation method of the present invention, preferably, the sodium salt is sodium hexametaphosphate, and the amount of sodium hexametaphosphate is 0.1 to 0.3 parts by weight. More preferably, the amount of sodium hexametaphosphate is 0.2 to 0.25 parts by weight. This helps to improve the suspension of cerium oxide polishing fluid and the dispersibility of cerium oxide particles in the polishing fluid, reduce the particle size of cerium oxide particles, and help to make the particle size distribution of cerium oxide particles narrower.
[0017] Electromagnetic stirring can be used to stir cerium oxide particles, sodium salts, magnesium aluminum silicate, and water.
[0018] Stirring can be carried out at a speed of 600 to 1000 rpm. Preferably, stirring is carried out at a speed of 700 to 900 rpm.
[0019] According to the preparation method of the present invention, preferably, step (1) includes the following steps: electromagnetically stirring sodium salt, magnesium aluminum silicate and water at a speed of 600-1000 rpm for 20-50 min to obtain a mixture; electromagnetically stirring the mixture with cerium oxide particles at a speed of 600-1000 rpm for 20-50 min to obtain cerium oxide sand milling slurry.
[0020] More preferably, step (1) includes the following steps: electromagnetically stirring sodium salts, magnesium aluminum silicate and water at a speed of 700-900 rpm for 30-40 min to obtain a mixture; electromagnetically stirring the mixture with cerium oxide particles at a speed of 700-900 rpm for 30-40 min to obtain cerium oxide sand milling slurry.
[0021] According to the preparation method of the present invention, preferably, it further includes the following step: calcining the cerium salt at 800-1100°C for 2-8 hours to obtain cerium oxide particles; wherein the cerium salt is selected from one or more of cerium carbonate and cerium oxalate.
[0022] The roasting temperature can be 800–1100℃; preferably 900–1000℃. The roasting time can be 2–8 hours; preferably 3–6 hours. Roasting can be carried out in a muffle furnace.
[0023] The cerium salt can be selected from one or more of cerium carbonate and cerium oxalate. Preferably, the cerium salt is cerium carbonate. The purity of the cerium salt can be greater than 99.9 wt%; preferably, the purity of the cerium salt is greater than 99.99 wt%.
[0024] According to the preparation method of the present invention, preferably, it further includes the following steps: adding ammonia water dropwise to an inorganic cerium salt aqueous solution to obtain a reaction product; centrifuging the reaction product to obtain a cerium oxide particle precursor; calcining the cerium oxide particle precursor at 700-900°C to obtain cerium oxide particles.
[0025] The inorganic cerium salt in the inorganic cerium salt aqueous solution is selected from one or more of cerium nitrate, cerium chloride, and cerium sulfate; the mass-to-volume ratio of the inorganic cerium salt to water in the inorganic cerium salt aqueous solution is (150-250) g:(4000-6000) mL; the concentration of the ammonia water is 30-60 wt%; and the volume ratio of the inorganic cerium salt aqueous solution to the ammonia water is (4000-6000):(150-350).
[0026] The inorganic cerium salt in the aqueous solution is selected from one or more of cerium nitrate, cerium chloride, and cerium sulfate. According to one embodiment of the invention, the inorganic cerium salt is cerium nitrate. The inorganic cerium salt can be used in its hydrate form, such as cerium nitrate hexahydrate. The purity of the inorganic cerium salt can be greater than 99.9 wt%; preferably, the purity of the inorganic cerium salt is greater than 99.99 wt%.
[0027] In the aqueous solution of inorganic cerium salt, the mass-to-volume ratio of inorganic cerium salt to water can be (150-250) g: (4000-6000) mL; preferably (180-220) g: (4500-5500) mL.
[0028] Water and inorganic cerium salt can be electromagnetically stirred at a speed of 600–1000 rpm, preferably 700–900 rpm, to obtain an aqueous solution of inorganic cerium salt.
[0029] The concentration of ammonia water can be 30–60 wt%; preferably 40–50 wt%.
[0030] The volume ratio of inorganic cerium salt aqueous solution to ammonia water can be (4000-6000):(150-350); preferably (4800-5500):(200-280).
[0031] According to the preparation method of the present invention, preferably, the dropping rate of ammonia water is 5 to 25 mL / min. More preferably, the dropping rate of ammonia water is 8 to 15 mL / min.
[0032] After the ammonia water is added dropwise, stir at a speed of 600-1000 rpm; preferably 700-900 rpm for 80-170 min; preferably 100-150 min to obtain the reaction product.
[0033] Preferably, the cerium oxide particle precursor is calcined at 800–850°C to obtain cerium oxide particles. The calcination time can be 0.5–5 h; preferably 1–3 h. The calcination can be carried out in a muffle furnace.
[0034] According to the preparation method of the present invention, preferably, in step (2), the circulation supply speed of cerium oxide sand milling liquid is 100-200 mL / min, the speed of the sand mill is 2000-4000 rpm, and the sand milling time is 1-4 h; the sand milling medium is zirconia beads with a diameter of 0.1-0.4 mm.
[0035] The abrasive media can be zirconia beads with a diameter of 0.1 to 0.4 mm; preferably, the diameter of the zirconia beads is 0.1 to 0.2 mm.
[0036] The circulation supply rate of cerium oxide grinding slurry can be 100-200 mL / min; preferably, the circulation supply rate of cerium oxide grinding slurry is 120-170 mL / min.
[0037] The speed of the sand mill can be 2000-4000 rpm; preferably, the speed of the sand mill is 3000-3800 rpm.
[0038] The grinding time can be 1 to 4 hours; preferably, the grinding time is 2 to 3 hours.
[0039] On the other hand, the present invention provides a cerium oxide polishing slurry, which is prepared by the aforementioned method.
[0040] The cerium oxide polishing slurry of the present invention does not produce a clear liquid layer on top after standing for 30 days, and there is no caking at the bottom.
[0041] In the cerium oxide polishing solution of the present invention, the maximum particle size of cerium oxide particles is ≤500 nm; preferably, the maximum particle size of cerium oxide particles is ≤400 nm. The particle size D of the cerium oxide particles... 50 The particle size is 70–80 nm; preferably, the particle size D of the cerium oxide particles is... 50 The particle size is 73-76 nm. In the cerium oxide polishing solution of the present invention, the cerium oxide particles are not easily agglomerated and have a small particle size.
[0042] In the cerium oxide polishing solution of the present invention, the particle size (D) of the cerium oxide particles is... 90 -D 10 ) / 2D 50 ≤1.5; preferably, (D 90 -D 10 ) / 2D 50 ≤1. In the cerium oxide polishing solution of the present invention, the particle size distribution of cerium oxide particles is narrow.
[0043] The preparation method of the present invention can improve the suspension properties of cerium oxide polishing slurry. Furthermore, the preparation method can improve the dispersibility of cerium oxide particles in the polishing slurry, reduce the particle size of cerium oxide particles, and make the particle size distribution of cerium oxide particles narrower. Attached Figure Description
[0044] Figure 1 The image shows the XRD patterns of the cerium oxide particles obtained in Example 1 and the standard PDF card.
[0045] Figure 2 The image shows a SEM image of the cerium oxide polishing solution obtained in Example 1.
[0046] Figure 3 This is a SEM image of the cerium oxide polishing solution obtained in Example 2.
[0047] Figure 4 This is a photograph of the cerium oxide polishing solution obtained in Example 1 after standing for 30 days. Detailed Implementation
[0048] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.
[0049] The test methods for the embodiments and comparative examples are described below:
[0050] XRD: Tests were performed using an X'Pert PRO X-ray diffractometer. The sample was ground into particles using a mortar and pestle, and X'Pert PRO X-ray diffractometer was used with a Cu target as the anode and Kα rays as the radiation source. The wavelength was... The scanning speed is 2° per second, and the test angle range is 5 to 80°.
[0051] SEM: The test was performed using a ZEISS Sigma 500 field emission scanning electron microscope. After ultrasonically dispersing the cerium oxide polishing slurry for 5 min, it was dropped onto a silicon wafer, dried, and then sputtered with gold. The microstructure of the sample was observed using a ZEISS Sigma 500 field emission scanning electron microscope.
[0052] Particle size: The particle size was measured using a Malvern 3000 laser particle size analyzer. Cerium oxide polishing slurry was dropped into the instrument, and particle size was measured under a 10% light-blocking condition.
[0053] Suspension: Place approximately 500 mL of cerium oxide polishing solution in a 500 mL test tube, place it on a horizontal platform, and let it stand at room temperature for 30 days. Observe the state of the cerium oxide polishing solution in the test tube after 30 days.
[0054] Example 1
[0055] Cerium carbonate (99.99 wt% purity) was placed in a muffle furnace and calcined at 1000 °C for 4 hours. After cooling, cerium oxide particles (D) were obtained. 50 (1-2 μm).
[0056] 0.4 g of sodium citrate and 2 g of magnesium aluminum silicate were placed in 400 mL of deionized water and then electromagnetically stirred at 800 rpm for 30 min to obtain a mixture. 60 g of cerium oxide particles were added to the mixture and then electromagnetically stirred at 800 rpm for 30 min to obtain a cerium oxide slurry.
[0057] Cerium oxide polishing slurry was placed in a sand mill for sand milling to obtain cerium oxide polishing slurry. During the sand milling process, the cerium oxide polishing slurry was supplied at a circulation rate of 140 mL / min, the sand mill speed was 3800 rpm, and the sand milling time was 2 hours. The sand milling media were zirconia beads with a diameter of 0.2 mm.
[0058] The particle size of cerium oxide particles in the obtained cerium oxide polishing solution and the suspension properties of the polishing solution are shown in Table 1.
[0059] Figure 1 This is an XRD pattern comparing the cerium oxide particles obtained in this embodiment with the standard PDF card. Figure 1 As can be seen, the XRD diffraction peaks of the cerium oxide particles obtained in this embodiment are sharp, corresponding to the diffraction peaks of CeO2 identified by the standard PDF card, which indicates that cerium oxide was successfully prepared.
[0060] Figure 2 This is a SEM image of the cerium oxide polishing slurry obtained in Example 1. Figure 2It can be seen that the cerium oxide particles are uniform, without sharp edges, and have good dispersibility in the cerium oxide polishing solution.
[0061] Figure 4 This is a photograph of the cerium oxide polishing solution obtained in Example 1 after standing for 30 days. Figure 4 It can be seen that the cerium oxide polishing slurry in this embodiment has good suspension properties. After standing for 30 days, there is no clear liquid layer on the top and no caking at the bottom.
[0062] Comparative Example 1
[0063] Except for the amount of sodium citrate (2g) and magnesium aluminum silicate (0.4g), the rest were the same as in Example 1. The particle size of cerium oxide in the obtained cerium oxide polishing solution and the suspension properties of the polishing solution are shown in Table 1.
[0064] Comparative Example 2
[0065] Except for replacing sodium citrate with sodium dodecylbenzenesulfonate, the process was the same as in Example 1. The particle size of the cerium oxide particles in the resulting cerium oxide polishing solution and the suspension properties of the polishing solution are shown in Table 1.
[0066] Comparative Example 3
[0067] Except for replacing sodium citrate with polyvinylpyrrolidone, the process was the same as in Example 1. The particle size of the cerium oxide particles in the resulting cerium oxide polishing solution and the suspension properties of the polishing solution are shown in Table 1.
[0068] Example 2
[0069] 200g of cerium nitrate hexahydrate (99.99wt% purity) was placed in 5000mL of deionized water and then stirred electromagnetically at 800rpm to obtain a cerium nitrate solution. 240mL of 50wt% ammonia solution was added dropwise to the cerium nitrate solution; after the ammonia solution was completely added, the mixture was stirred at 800rpm for 120min to obtain the reaction product. The ammonia solution was added at a rate of 10mL / min. The reaction product was centrifuged to obtain a cerium oxide particle precursor. The cerium oxide particle precursor was placed in a muffle furnace and calcined at 800℃ for 2h. After cooling, cerium oxide particles (D) were obtained. 50 (1–1.5 μm).
[0070] 0.2 g of sodium hexametaphosphate and 2 g of magnesium aluminum silicate were placed in 400 mL of deionized water and then electromagnetically stirred at 800 rpm for 30 min to obtain a mixture. 60 g of cerium oxide particles were added to the mixture and then electromagnetically stirred at 800 rpm for 30 min to obtain a cerium oxide slurry.
[0071] Cerium oxide polishing slurry was placed in a sand mill for sand milling to obtain cerium oxide polishing slurry. During the sand milling process, the cerium oxide polishing slurry was supplied at a circulation rate of 140 mL / min, the sand mill speed was 3800 rpm, and the sand milling time was 2 hours. The sand milling media were zirconia beads with a diameter of 0.2 mm.
[0072] The particle size of cerium oxide particles in the obtained cerium oxide polishing solution and the suspension properties of the polishing solution are shown in Table 1.
[0073] Figure 3 This is a SEM image of the cerium oxide polishing slurry obtained in Example 2. Figure 3 It can be seen that the cerium oxide particles are uniform, without sharp edges, and have good dispersibility in the cerium oxide polishing solution.
[0074] Comparative Example 4
[0075] Except for the amount of sodium hexametaphosphate (2g) and magnesium aluminum silicate (0.2g), the rest were the same as in Example 2. The particle size of cerium oxide in the obtained cerium oxide polishing solution and the suspension properties of the polishing solution are shown in Table 1.
[0076] Comparative Example 5
[0077] Except for replacing sodium hexametaphosphate with sodium dodecylbenzenesulfonate, the process was the same as in Example 2. The particle size of cerium oxide in the resulting cerium oxide polishing solution and the suspension properties of the polishing solution are shown in Table 1.
[0078] Comparative Example 6
[0079] Except for replacing sodium hexametaphosphate with polyvinylpyrrolidone, the process was the same as in Example 2. The particle size of cerium oxide in the resulting cerium oxide polishing solution and the suspension properties of the polishing solution are shown in Table 1.
[0080] Table 1
[0081]
[0082] As demonstrated in Examples 1 and Comparative Examples 1-3, and Examples 2 and Comparative Examples 4-6, appropriate amounts of magnesium aluminum silicate and sodium citrate or sodium hexametaphosphate can improve the suspension of cerium oxide polishing slurry, reduce the agglomeration tendency of cerium oxide particles, decrease the particle size of cerium oxide particles in the slurry, and narrow the particle size distribution of cerium oxide particles. In Comparative Examples 2-3 and 5-6, after sand milling, the cerium oxide in the polishing slurry was unstable and agglomerated, significantly increasing the particle size of cerium oxide particles and resulting in a wide particle size distribution and poor uniformity. The suspension of the cerium oxide polishing slurry was poor, and a clear liquid layer appeared at the top after long-term storage. In Comparative Examples 1 and 4, the cerium oxide polishing slurry had poor suspension, a clear liquid layer appeared at the top after long-term storage, and caking occurred at the bottom.
[0083] This invention is not limited to the above-described embodiments. Any modifications, improvements, or substitutions that can be conceived by those skilled in the art without departing from the essential content of this invention fall within the scope of this invention.
Claims
1. A method for preparing a cerium oxide polishing slurry, characterized in that, Includes the following steps: (1) Stir 45-75 parts by weight of cerium oxide particles, 0.1-0.6 parts by weight of sodium salts, 0.8-4 parts by weight of magnesium aluminum silicate and water to obtain cerium oxide sand milling slurry; wherein, the sodium salts are selected from one or more of sodium citrate and sodium hexametaphosphate, and the amount of water used is 300-500 mL based on 60 g of cerium oxide particles; (2) The cerium oxide sand milling liquid is subjected to sand milling treatment to obtain cerium oxide polishing liquid.
2. The preparation method according to claim 1, characterized in that, The particle size D of the cerium oxide particles 50 <5μm.
3. The preparation method according to claim 1, characterized in that, The sodium salt is sodium citrate, and the amount of sodium citrate used is 0.3 to 0.5 parts by weight.
4. The preparation method according to claim 1, characterized in that, The sodium salt is sodium hexametaphosphate, and the amount of sodium hexametaphosphate used is 0.1 to 0.3 parts by weight.
5. The preparation method according to claim 1, characterized in that, Step (1) includes the following steps: Sodium salts, magnesium aluminum silicate, and water are electromagnetically stirred at 600–1000 rpm for 20–50 min to obtain a mixture. The mixture is then electromagnetically stirred with cerium oxide particles at 600–1000 rpm for 20–50 min to obtain a cerium oxide sand milling slurry.
6. The preparation method according to claim 1, characterized in that, It also includes the following steps: Cerium salt is calcined at 800–1100°C for 2–8 hours to obtain cerium oxide particles; wherein the cerium salt is selected from one or more of cerium carbonate and cerium oxalate.
7. The preparation method according to claim 1, characterized in that, It also includes the following steps: Ammonia water was added dropwise to an inorganic cerium salt aqueous solution to obtain a reaction product; the reaction product was centrifuged to obtain a cerium oxide particle precursor; the cerium oxide particle precursor was calcined at 700–900 °C to obtain cerium oxide particles. The inorganic cerium salt in the inorganic cerium salt aqueous solution is selected from one or more of cerium nitrate, cerium chloride, and cerium sulfate; the mass-to-volume ratio of the inorganic cerium salt to water in the inorganic cerium salt aqueous solution is (150-250) g:(4000-6000) mL; the concentration of the ammonia water is 30-60 wt%; and the volume ratio of the inorganic cerium salt aqueous solution to the ammonia water is (4000-6000):(150-350).
8. The preparation method according to claim 7, characterized in that, The ammonia solution is added at a rate of 5–25 mL / min.
9. The preparation method according to claim 1, characterized in that, In step (2), the cerium oxide grinding fluid circulation supply rate is 100-200 mL / min, the grinding mill speed is 2000-4000 rpm, and the grinding time is 1-4 h; the grinding media are zirconia beads with a diameter of 0.1-0.4 mm.
10. A cerium oxide polishing slurry, characterized in that, The cerium oxide polishing slurry is prepared by the preparation method according to any one of claims 1 to 9.