Preparation process of optical polishing nanoparticle suspension

Abstract

The invention discloses a preparation process of an optical polishing nanoparticle suspension, and particularly relates to the technical field of precision optical processing, and the process comprises six steps of material preparation, nanoparticle pretreatment, disperse system construction, functional auxiliary agent compounding, system blending and refining. The preparation method comprises the following steps: pretreating cerium oxide nanoparticles to prepare CeO2 (at) S < O2 > composite particles, sequentially adding deionized water, an alcohol solvent, a dispersant and the CeO2 (at) S < O2 > composite particles, carrying out ultrasonic wave and high shear dispersion to ensure uniform dispersion of the particles, slowly adding a compounded transparent sol and a functional auxiliary agent emulsion into the system, adjusting the pH value to 9.8-10.2, and finally carrying out centrifugation and ultrafiltration refining to obtain the high-purity CeO2 (at) S < O2 > composite particles. The prepared optical polishing nanoparticle suspension is uniform in particle size distribution and excellent in stability. The process is simple, convenient and efficient, the prepared suspension has excellent polishing performance, low surface defect rate and good environmental adaptability, the surface quality and machining efficiency of optical elements are remarkably improved, and the suspension has high application value.

Description

Technical Field

[0001] This invention relates to the field of precision optical processing technology, and in particular to a process for preparing an optical polishing nanoparticle suspension. Background Technology

[0002] Optical devices are widely used in modern high-precision electronics, communications, aerospace, lasers, and medical fields, placing extremely high demands on their surface quality. Polishing of optical components such as glass, crystals, and silicon wafers is a crucial step in ensuring their flatness, surface roughness, and smoothness. Among these, nanoparticle polishing slurries, as a highly efficient and low-loss polishing material, are widely researched and applied due to their small particle size, high surface activity, and significant chemical-mechanical interaction.

[0003] Existing optical polishing nanoparticle suspensions typically use cerium oxide (CeO2) as the main polishing particles, supplemented with certain organic or inorganic dispersants, stabilizers, pH adjusters, etc., to achieve efficient polishing of material surfaces through a combined chemical-mechanical approach. However, existing technologies still have significant shortcomings in the following aspects: severe particle agglomeration, poor chemical-mechanical synergy efficiency, potential for scratching or corrosion of substrate surfaces, poor environmental adaptability, inaccurate pH control, and lack of high-performance composite particle design.

[0004] Therefore, we propose a process for preparing optically polished nanoparticle suspensions. Summary of the Invention

[0005] The main objective of this invention is to provide a process for preparing optically polished nanoparticle suspensions, which aims to improve the dispersion stability of nanoparticles, optimize the chemomechanical synergistic properties of the polishing solution, and improve the uniformity and performance of the suspension by precisely controlling the pH value and reaction conditions.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A process for preparing an optically polished nanoparticle suspension, the specific steps of which are as follows:

[0008] Step 1: Material Preparation: 80-120 parts cerium oxide nanoparticles, 0.2-1 parts ammonium polyacrylate, 0.2-0.8 parts carboxymethyl cellulose nanoparticles, 0.1-0.3 parts silane coupling agent, 0.1 parts polyether-modified silicone oil, 80-90 parts deionized water, 2-7 parts glycerol, 2-4 parts isopropanol, 0.1-0.5 parts sodium citrate, 0.1-0.2 parts benzotriazole, 0.3-0.7 parts nano zinc oxide, 0.5-1 part tetramethylammonium hydroxide, 0.1-0.3 parts polyvinylpyrrolidone, and 0.03-0.07 parts sodium dodecyl sulfate;

[0009] Step 2, Nanoparticle Pretreatment: Cerium oxide nanoparticles were placed in a vacuum drying oven for 2 hours to dehydrate. Under nitrogen protection, silane coupling agent was prepared into an ethanol solution with a concentration of 5 wt%, sprayed in, and treated at 200 rpm for 30 minutes. Then, heat-treated at 20°C for 1 hour to form a dense SiO2 shell, thus forming CeO2@SiO2 particles.

[0010] Step 3: Constructing the dispersion system: Add the prepared components sequentially to the stainless steel reactor. Deionized water, glycerol, isopropanol, ammonium polyacrylate, and sodium dodecyl sulfate were premixed at 1000 rpm for 15 min, and then added to the pretreated CeO2@SiO2 particles in step 2 in four batches, followed by ultrasonic treatment.

[0011] Step 4: Compound functional additives: Take carboxymethyl cellulose nanoparticles, tetramethyl ammonium hydroxide, and the remaining... Deionized water was magnetically stirred in a 50°C water bath for 2 hours to form a transparent sol; sodium citrate, benzotriazole, nano zinc oxide, and polyvinylpyrrolidone were added to a separate container and subjected to ultrasonic emulsification to form a homogeneous emulsion.

[0012] Step 5, Mixing: Slowly add the transparent sol from Step 4 to the dispersion system constructed in Step 3. After mixing evenly, add the homogeneous emulsion and polyether-modified silicone oil prepared in Step 4. Adjust the pH value to between 9.8 and 10.2 using ammonia water and react for 1 hour under a pressure of 0.2 MPa.

[0013] Step 6, Refining: Use a disc centrifuge to separate and remove aggregates >100nm, and then filter again with a 10kDa ultrafiltration membrane to obtain the optically polished nanoparticle suspension.

[0014] Preferably, in step 3, the specific steps for adding the pretreated CeO2@SiO2 particles from step 2 in four batches are as follows:

[0015] The first batch added to the total. Disperse for 8 minutes at a speed of 1200 rpm and a temperature of 30°C;

[0016] The first batch added to the total. Disperse for 10 min at a rotation speed of 1500 rpm and a temperature of 35℃;

[0017] The first batch added to the total. Disperse for 12 minutes at a speed of 1800 rpm and a temperature of 40℃;

[0018] The first batch added to the total. Disperse for 15 minutes at a rotation speed of 2200 rpm and a temperature of 45℃;

[0019] In addition, each batch is subjected to 5 minutes of ultrasonic treatment at a time interval of 40 kHz and 500 W.

[0020] Preferably, in step 2, the temperature at which the cerium oxide nanoparticles are placed in a vacuum drying oven for dehydration for 2 hours is 80°C and the pressure is -0.1 MPa.

[0021] Preferably, the parameters for ultrasonic emulsification in step 4 are 20kHz and 300W.

[0022] Preferably, in step 5, the transparent sol from step 4 is slowly added to the dispersion system constructed in step 3 and mixed by maintaining stirring at 1500 rpm for 2 hours, with the temperature at 45°C and the dropping rate at 5 mL / min.

[0023] Preferably, the cerium oxide nanoparticles used in step 1 have a particle size of 50-60 nm.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. This invention modifies cerium oxide nanoparticles by vacuum dehydration and silane coupling coating to form a dense CeO2@SiO2 core-shell structure, which enhances the hydrophilicity and interfacial compatibility of the particles, significantly reduces the tendency of particle aggregation, and improves the long-term stability and dispersion uniformity of the polishing slurry.

[0026] 2. By introducing a variety of functional additives such as polyether-modified silicone oil, benzotriazole, and polyvinylpyrrolidone, and combining them with the synergistic effect of nano zinc oxide and sodium citrate, this invention not only improves the lubrication effect but also effectively inhibits corrosion and scratches on the substrate surface, achieving synergistic optimization of chemical etching and mechanical wear, and significantly improving polishing efficiency and surface quality.

[0027] 3. This invention employs a batch ultrasonic + shear dispersion process strategy to precisely control the particle addition rate, temperature, and rotation speed, thereby improving the uniformity of particles during dispersion and reducing batch-to-batch differences. Simultaneously, by maintaining the pH value within the range of 9.8-10.2, the chemical stability of the system is ensured, further enhancing the consistency and repeatability of the polishing solution. Detailed Implementation

[0028] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0029] This invention provides a process for preparing an optical polishing nanoparticle suspension, using raw materials comprising the following components: 80-120 parts of cerium oxide nanoparticles, 0.2-1 parts of ammonium polyacrylate, 0.2-0.8 parts of carboxymethyl nanocellulose, 0.1-0.3 parts of silane coupling agent, 0.1 parts of polyether-modified silicone oil, 80-90 parts of deionized water, 2-7 parts of glycerol, 2-4 parts of isopropanol, 0.1-0.5 parts of sodium citrate, 0.1-0.2 parts of benzotriazole, 0.3-0.7 parts of nano zinc oxide, 0.5-1 parts of tetramethylammonium hydroxide, 0.1-0.3 parts of polyvinylpyrrolidone, and 0.03-0.07 parts of sodium dodecyl sulfate.

[0030] In this invention, cerium oxide nanoparticles, serving as the primary polishing medium, play a crucial role in polishing. They possess excellent tribological properties and high chemical reactivity, effectively removing material from optical surfaces under relatively low applied pressure while minimizing scratches. The CeO2 particles in this invention have a particle size of 50-60 nm and employ a core-shell structure (CeO2@SiO2). Their surface is modified through silanization to form a SiO2 shell layer approximately 2-3 nm thick. This not only improves particle dispersibility but also enhances their hydrophilicity, resulting in better dispersion stability in solvents.

[0031] Additionally, it should be noted that ammonium polyacrylate is a common water-soluble polymeric dispersant that can stably disperse particles in solution through electrostatic interaction, preventing particle aggregation; carboxymethyl cellulose nanoparticles, as a natural polymeric material, can form a stable colloidal system in aqueous solution, providing physical steric hindrance and thus increasing particle dispersibility; sodium dodecyl sulfate, as an anionic surfactant, can effectively reduce the surface tension of the liquid and enhance the affinity between particles and solvent; the silane coupling agent, specifically the common KH-560, can enhance the compatibility between organic and inorganic substances. Adding it to the surface of CeO2@SiO2 particles can improve the binding force between particles and the dispersion system, reducing particle agglomeration; these materials serve as the dispersion stabilizing system in this invention.

[0032] Meanwhile, glycerol can effectively improve wettability and increase the surface tension of the polishing slurry, thereby improving the uniformity and optical surface quality of the polishing slurry; isopropanol, as a solvent, helps the particles in the polishing slurry to disperse better and improves the effect of the dispersant; through the synergistic effect of glycerol and isopropanol, the polishing slurry can better wet the surface to be processed, reduce surface defects, and improve the polishing effect.

[0033] Sodium citrate, in this invention, acts as a chelating agent, forming stable complexes with metal ions in the solution to prevent metal ions from interfering with the polishing process and avoiding damage to the equipment and workpiece surfaces. Benzotriazole is an excellent corrosion inhibitor that protects the equipment and workpiece surfaces from corrosion during polishing and reduces surface defects caused by wear. Nano zinc oxide has antibacterial properties, inhibiting the growth of microorganisms and ensuring the cleanliness of the polishing solution during long-term use. Tetramethylammonium hydroxide, as a pH buffer, maintains the pH stability of the polishing solution during polishing, avoiding performance fluctuations caused by pH changes. All of these materials are used as functional additives in this invention.

[0034] It should also be noted that the present invention uses polyvinylpyrrolidone as a stabilizer, which helps to improve particle dispersibility, prevent particle aggregation or sedimentation, enhance the stability of the suspension, effectively improve the rheological properties of the polishing fluid, and ensure that the particles remain in a uniformly dispersed state for a long time.

[0035] Through the precise combination and optimization of the above components, the optical polishing fluid of the present invention achieves significant stability, excellent polishing performance and long service life, which can meet the needs of high-end optics, semiconductors and other precision material processing.

[0036] The present invention is further disclosed below with reference to specific embodiments and comparative examples: Examples 1-5 are preferred embodiments of the present invention for preparing optical polishing nanoparticle suspensions, and Comparative Examples 1-3 are examples of missing key components or adjusted parameters.

[0037] Example 1

[0038] In this embodiment, an optically polished nanoparticle suspension was prepared according to the following steps:

[0039] Step 1, Material Preparation: 100 parts cerium oxide nanoparticles, 0.5 parts ammonium polyacrylate, 0.5 parts carboxymethyl cellulose nanoparticles, 0.2 parts silane coupling agent, 0.1 parts polyether modified silicone oil, 85 parts deionized water, 5 parts glycerol, 3 parts isopropanol, 0.3 parts sodium citrate, 0.1 parts benzotriazole, 0.5 parts nano zinc oxide, 0.8 parts tetramethylammonium hydroxide, 0.2 parts polyvinylpyrrolidone, and 0.05 parts sodium dodecyl sulfate;

[0040] Step 2, Nanoparticle Pretreatment: Cerium oxide nanoparticles were placed in a vacuum drying oven (temperature 80℃, pressure -0.1MPa) for 2 hours to dehydrate. Under nitrogen protection, silane coupling agent was prepared into a 5wt% ethanol solution, sprayed in, and treated at 200 rpm for 30 minutes. Then, heat-treated at 20℃ for 1 hour to form a dense SiO2 shell, thus forming CeO2@SiO2 particles.

[0041] Step 3: Constructing the dispersion system: Add the prepared components sequentially to the stainless steel reactor. Deionized water, glycerol, isopropanol, ammonium polyacrylate, and sodium dodecyl sulfate were premixed at 1000 rpm for 15 min, and then added to the pretreated CeO2@SiO2 particles in step 2 in four batches, followed by ultrasonic treatment.

[0042] The specific steps for adding CeO2@SiO2 particles in four batches are as follows:

[0043] The first batch added to the total. Disperse for 8 minutes at a speed of 1200 rpm and a temperature of 30°C;

[0044] The first batch added to the total. Disperse for 10 min at a rotation speed of 1500 rpm and a temperature of 35℃;

[0045] The first batch added to the total. Disperse for 12 minutes at a speed of 1800 rpm and a temperature of 40℃;

[0046] The first batch added to the total. Disperse for 15 minutes at a rotation speed of 2200 rpm and a temperature of 45℃;

[0047] In addition, each batch is subjected to 5 minutes of ultrasonic treatment at a time interval of 40 kHz and 500 W.

[0048] Step 4: Compound functional additives: Take carboxymethyl cellulose nanoparticles, tetramethyl ammonium hydroxide, and the remaining... Deionized water was magnetically stirred in a 50°C water bath for 2 hours to form a transparent sol; sodium citrate, benzotriazole, nano zinc oxide, and polyvinylpyrrolidone were added to a separate container and ultrasonically emulsified (20kHz, 300W) to form a homogeneous emulsion.

[0049] Step 5, Mixing: Slowly add the transparent sol from Step 4 to the dispersion system constructed in Step 3, maintain stirring at 1500 rpm for 2 hours, and keep the temperature at 45℃ during stirring. After mixing evenly, add the homogeneous emulsion and polyether modified silicone oil prepared in Step 4, adjust the pH value to between 9.8 and 10.2 with ammonia water, and react at 0.2 MPa pressure for 1 hour.

[0050] Step 6, Refining: Use a disc centrifuge to separate and remove aggregates >100nm, and then filter again with a 10kDa ultrafiltration membrane to obtain the optically polished nanoparticle suspension.

[0051] Example 2

[0052] The preparation steps in this embodiment are exactly the same as those in Example 1, with the only difference being the adjustment of the raw material ratio as follows:

[0053] The composition includes 80 parts cerium oxide nanoparticles, 0.2 parts ammonium polyacrylate, 0.2 parts carboxymethyl cellulose nanoparticles, 0.1 parts silane coupling agent, 0.1 parts polyether modified silicone oil, 80 parts deionized water, 2 parts glycerol, 2 parts isopropanol, 0.1 parts sodium citrate, 0.1 parts benzotriazole, 0.3 parts nano zinc oxide, 0.5 parts tetramethylammonium hydroxide, 0.1 parts polyvinylpyrrolidone, and 0.03 parts sodium dodecyl sulfate.

[0054] Example 3

[0055] The preparation steps in this embodiment are exactly the same as those in Example 1, with the only difference being the adjustment of the raw material ratio as follows:

[0056] The composition includes 120 parts cerium oxide nanoparticles, 1 part ammonium polyacrylate, 0.8 parts carboxymethyl nanocellulose, 0.3 parts silane coupling agent, 0.1 parts polyether modified silicone oil, 90 parts deionized water, 7 parts glycerol, 4 parts isopropanol, 0.5 parts sodium citrate, 0.2 parts benzotriazole, 0.7 parts nano zinc oxide, 1 part tetramethylammonium hydroxide, 0.3 parts polyvinylpyrrolidone, and 0.07 parts sodium dodecyl sulfate.

[0057] Example 4

[0058] The preparation steps in this embodiment are exactly the same as those in Example 1, with the only difference being the adjustment of the raw material ratio as follows:

[0059] The composition includes 90 parts cerium oxide nanoparticles, 0.4 parts ammonium polyacrylate, 0.3 parts carboxymethyl nanocellulose, 0.2 parts silane coupling agent, 0.1 parts polyether modified silicone oil, 82 parts deionized water, 4 parts glycerol, 3 parts isopropanol, 0.2 parts sodium citrate, 0.1 parts benzotriazole, 0.4 parts nano zinc oxide, 0.6 parts tetramethylammonium hydroxide, 0.2 parts polyvinylpyrrolidone, and 0.04 parts sodium dodecyl sulfate.

[0060] Example 5

[0061] The preparation steps in this embodiment are exactly the same as those in Example 1, with the only difference being the adjustment of the raw material ratio as follows:

[0062] The composition includes 110 parts cerium oxide nanoparticles, 0.8 parts ammonium polyacrylate, 0.6 parts carboxymethyl nanocellulose, 0.2 parts silane coupling agent, 0.1 parts polyether modified silicone oil, 88 parts deionized water, 6 parts glycerol, 3 parts isopropanol, 0.4 parts sodium citrate, 0.2 parts benzotriazole, 0.6 parts nano zinc oxide, 0.8 parts tetramethylammonium hydroxide, 0.2 parts polyvinylpyrrolidone, and 0.06 parts sodium dodecyl sulfate.

[0063] Comparative Example 1

[0064] This comparative example is based on Example 1, but without silanization modification or SiO2 shell coating of the CeO2 particles; only unmodified CeO2 particles are used. Other components and preparation steps remain consistent with Example 1.

[0065] Comparative Example 2

[0066] This comparative example is based on Example 1, except that carboxymethyl cellulose nanofibers are removed and no spatial framework structure is constructed. Other components remain the same as in Example 1, and the preparation steps are adjusted accordingly based on the reduced raw materials.

[0067] Comparative Example 3

[0068] This comparative example is based on Example 1, but without the addition of functional additives, nano zinc oxide, tetramethylammonium hydroxide, sodium citrate, and benzotriazole. Other components remain the same as in Example 1, and the preparation steps were adjusted accordingly to account for the reduced amount of raw materials.

[0069] The samples prepared in Examples 1-5 and Comparative Examples 1-3 were subjected to the following tests:

[0070] I. Suspension Stability Test: Accelerated sedimentation tests were conducted using a German LUMiSizer sedimentation analyzer according to ISO 13318-2. The final test results are shown in Table 1.

[0071] II. Storage Stability Test: The cells were placed at 25°C and the sedimentation rate (%) was observed over 30 days. The zeta potential was tested using ZetasizerNano (refer to ISO 13099-2). The final test results are shown in Table 1.

[0072] III. Polishing Ability Test: Using K9 optical glass as the substrate, the material removal rate (μm / h) was measured using a polishing machine (load 2N, speed 200rpm, polishing time 30min). The final test results are shown in Table 1.

[0073] IV. pH Stability Test: pH changes were recorded using a pH meter, and the pH fluctuation range was observed over one week (temperature 25±1℃). The final test results are shown in Table 1.

[0074] Table 1: Performance test results of samples prepared in Examples 1-5 and Comparative Examples 1-3:

[0075]

[0076] The results above show that:

[0077] Regarding dispersion stability: Examples 1-5: accelerated sedimentation rate was <5%, static sedimentation rate was <3%, and the absolute value of Zeta potential was large (approximately -40mV), indicating high particle stability and good homogeneity of the suspension system. Comparative Examples 1-3: accelerated sedimentation rate increased significantly, reaching as high as 22.7% in Comparative Example 1; the absolute value of Zeta potential decreased significantly, especially in Comparative Example 1, which was only -27.3mV, indicating that particles easily aggregated and the system had poor stability. Comparative Example 3 was slightly better than the first two, but still significantly worse than the examples.

[0078] Regarding polishing removal rate: Examples 1-5 all showed high and stable polishing efficiency, ranging from 1.29 to 1.35 μm / h; Comparative Example 1 had the lowest efficiency, at only 0.98 μm / h; Comparative Examples 2 and 3 were slightly better but still lower than the examples, indicating a decrease in chemimechanical synergistic efficiency.

[0079] Regarding pH stability: the pH fluctuation of the examples was controlled within ±0.1–0.2, indicating good system stability; the fluctuation of Comparative Example 3 reached ±0.8, indicating that the solution was prone to change during storage or use and had poor reliability.

[0080] Comparative Example 1: SiO2 coating lacking CeO2 (no core-shell structure formed) has a smaller Zeta potential, severe agglomeration, rapid sedimentation (22.7%), poor dispersibility, and the lowest removal rate (0.98%).

[0081] Comparative Example 2: Removal of ammonium polyacrylate (or its excessive amount) resulted in insufficient dispersant, leading to decreased particle stability, reduced Zeta potential (-33.1), weakened polishing performance, and moderate sedimentation rate.

[0082] Comparative Example 3: Without the addition of nano zinc oxide, tetramethylammonium hydroxide, sodium citrate, and benzotriazole, the polishing solution lacked corrosion inhibition / lubrication functions. Although the dispersibility was acceptable (Zeta potential -38.2), the pH fluctuated greatly (±0.8), resulting in extremely poor stability in use.

[0083] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A process for preparing an optically polished nanoparticle suspension, characterized in that, The specific steps are as follows: Step 1: Material Preparation: 80-120 parts cerium oxide nanoparticles, 0.2-1 parts ammonium polyacrylate, 0.2-0.8 parts carboxymethyl cellulose nanoparticles, 0.1-0.3 parts silane coupling agent, 0.1 parts polyether-modified silicone oil, 80-90 parts deionized water, 2-7 parts glycerol, 2-4 parts isopropanol, 0.1-0.5 parts sodium citrate, 0.1-0.2 parts benzotriazole, 0.3-0.7 parts nano zinc oxide, 0.5-1 part tetramethylammonium hydroxide, 0.1-0.3 parts polyvinylpyrrolidone, and 0.03-0.07 parts sodium dodecyl sulfate; Step 2, Nanoparticle Pretreatment: Cerium oxide nanoparticles were placed in a vacuum drying oven for 2 hours to dehydrate. Under nitrogen protection, silane coupling agent was prepared into an ethanol solution with a concentration of 5 wt%, sprayed in, and treated at 200 rpm for 30 minutes. Then, heat-treated at 20°C for 1 hour to form a dense SiO2 shell, thus forming CeO2@SiO2 particles. Step 3: Constructing the dispersion system: Add the prepared components sequentially to the stainless steel reactor. Deionized water, glycerol, isopropanol, ammonium polyacrylate, and sodium dodecyl sulfate were premixed at 1000 rpm for 15 min, and then added to the pretreated CeO2@SiO2 particles in step 2 in four batches, followed by ultrasonic treatment. Step 4: Compound functional additives: Take carboxymethyl cellulose nanoparticles, tetramethyl ammonium hydroxide, and the remaining... Deionized water was magnetically stirred in a 50°C water bath for 2 hours to form a transparent sol; sodium citrate, benzotriazole, nano zinc oxide, and polyvinylpyrrolidone were added to a separate container and subjected to ultrasonic emulsification to form a homogeneous emulsion. Step 5, Mixing: Slowly add the transparent sol from Step 4 to the dispersion system constructed in Step 3. After mixing evenly, add the homogeneous emulsion and polyether-modified silicone oil prepared in Step 4. Adjust the pH value to between 9.8 and 10.2 using ammonia water and react for 1 hour under a pressure of 0.2 MPa. Step 6, Refining: Use a disc centrifuge to separate and remove aggregates >100nm, and then filter again with a 10kDa ultrafiltration membrane to obtain the optically polished nanoparticle suspension.

2. The process for preparing optically polished nanoparticle suspension according to claim 1, characterized in that... In step 3, the specific steps for adding the pretreated CeO2@SiO2 particles from step 2 in four batches are as follows: The first batch added to the total. Disperse for 8 minutes at a speed of 1200 rpm and a temperature of 30°C; The first batch added to the total. Disperse for 10 min at a rotation speed of 1500 rpm and a temperature of 35℃; The first batch added to the total. Disperse for 12 minutes at a speed of 1800 rpm and a temperature of 40℃; The first batch added to the total. Disperse for 15 minutes at a rotation speed of 2200 rpm and a temperature of 45℃; In addition, each batch is subjected to 5 minutes of ultrasonic treatment at a time interval of 40 kHz and 500 W.

3. The process for preparing optically polished nanoparticle suspension according to claim 1, characterized in that... In step 2, the cerium oxide nanoparticles are placed in a vacuum drying oven at 80°C and a pressure of -0.1 MPa for 2 hours to dehydrate.

4. The process for preparing optically polished nanoparticle suspension according to claim 1, characterized in that... The parameters for ultrasonic emulsification in step 4 are 20kHz and 300W.

5. The process for preparing optically polished nanoparticle suspension according to claim 1, characterized in that... In step 5, the transparent sol from step 4 is slowly added to the dispersion system constructed in step 3 and mixed by maintaining stirring at 1500 rpm for 2 hours, with the temperature at 45°C and the dropping rate at 5 mL / min.

6. The process for preparing optically polished nanoparticle suspension according to claim 1, characterized in that... The cerium oxide nanoparticles used in step 1 have a particle size of 50-60 nm.

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