Preparation method of cerium oxide abrasive particles and cerium oxide abrasive particles

Abstract

The invention provides a preparation method of cerium oxide abrasive particles and the cerium oxide abrasive particles. In the preparation method, a tackifier with a high K value (Fikentscher K value) is added into a reaction system, cerium oxycarbonate precursor particles are synthesized, the tackifier forms a protective layer around the cerium oxycarbonate precursor particles, and aggregation and anisotropic growth of the cerium oxycarbonate precursor particles are inhibited; and calcining the cerium oxycarbonate precursor particles to obtain the spherical cerium oxide abrasive particles with round morphology.

Description

Technical Field

[0001] This application relates to the field of chemical mechanical polishing technology, and in particular to a method for preparing cerium oxide abrasive particles and the cerium oxide abrasive particles themselves. Background Technology

[0002] Currently, cerium oxide abrasive preparation technologies commonly employ co-precipitation, sol-gel, or hydrothermal synthesis processes. In these processes, potassium hydroxide / sodium hydroxide and ammonia are often added to the reaction system as precipitants to obtain nanoparticles with regular morphologies. However, the slow precipitation synthesis of spherical cerium oxide through urea decomposition is highly susceptible to temperature and local concentration variations, easily leading to uneven nucleation and the formation of cerium oxide particles with inconsistent sizes and poor sphericity, even inducing significant particle fusion. Furthermore, due to the low viscosity of the reaction system, newly formed particles easily migrate and collide frequently in the early stages, causing local aggregation and even irreversible agglomeration. During subsequent drying or high-temperature calcination, the high surface energy of nano-sized cerium oxide further exacerbates the formation of hard agglomerates. Ultimately, cerium oxide abrasives prepared by this method generally suffer from irregular morphology and low sphericity. Such abrasives are difficult to maintain a stable material removal rate in precision polishing applications and are prone to scratches or micro-defects on the workpiece surface, severely restricting the surface processing quality of high-end materials such as optical glass and semiconductor wafers.

[0003] Therefore, there is an urgent need to develop a method for preparing cerium oxide abrasive particles that can effectively control the morphology of the abrasive particles and have high sphericity. Summary of the Invention This application provides a method for preparing cerium oxide abrasive particles and the cerium oxide abrasive particles themselves. By adding a thickener with a high K value to the reaction system, the overall viscosity of the reaction system is increased, so that the prepared cerium oxide abrasive particles maintain a regular spherical morphology.

[0004] To achieve the above objectives, the embodiments of this application adopt the following technical solutions: In a first aspect, embodiments of this application provide a method for preparing cerium oxide abrasive grains, comprising: adding a thickener with a high K value (Fikentscher K value) to a reaction system and synthesizing cerium oxycarbonate precursor particles, wherein the thickener forms a protective layer around the cerium oxycarbonate precursor particles to inhibit the aggregation and anisotropic growth of the cerium oxycarbonate precursor particles; and calcining the cerium oxycarbonate precursor particles to obtain spherical cerium oxide abrasive grains with a well-rounded morphology.

[0005] According to some embodiments of this application, the tackifier is polyvinylpyrrolidone.

[0006] According to some embodiments of this application, the K value of the polyvinylpyrrolidone is 30-120.

[0007] According to some embodiments of this application, the molecular weight of the polyvinylpyrrolidone is 120,000 g / mol - 1200,000 g / mol.

[0008] According to some embodiments of this application, the mass concentration of the polyvinylpyrrolidone in the reaction system ranges from 0.01wt% to 20wt%.

[0009] According to some embodiments of this application, the synthesis of cerium oxycarbonate precursor particles includes the following reaction under heating for a preset time: adding urea and soluble cerium salt to the reaction system, wherein the urea is decomposed by heating and then hydrolyzed to generate carbonate; the carbonate reacts with the cerium salt to precipitate and form the cerium oxycarbonate precursor particles.

[0010] According to some embodiments of this application, the heating temperature range is 55°C-99°C.

[0011] According to some embodiments of this application, within the heating temperature range, the viscosity of the reaction system is from 1 mPa·s to 100 mPa·s.

[0012] According to some embodiments of this application, the preset time is 1h-72h.

[0013] According to some embodiments of this application, the calcination temperature range is 300℃-1200℃.

[0014] According to some embodiments of this application, the calcination time is 15 min - 10 h.

[0015] According to some embodiments of this application, the cerium oxide abrasive grains have a polydisperse particle size distribution.

[0016] Secondly, embodiments of this application provide cerium oxide abrasive particles, which are prepared using the preparation method described in any one of the first aspects above. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart of a method for preparing cerium oxide abrasive particles according to an embodiment of this application is shown; Figure 2A flowchart is shown below illustrating a method for synthesizing cerium oxycarbonate precursor particles according to an embodiment of this application; Figure 3 A scanning electron microscope image of a first type of cerium oxide abrasive grain provided according to Embodiment 1 of this application is shown; Figure 4 A scanning electron microscope image of a second type of cerium oxide abrasive grain provided in Comparative Example 2 of this application is shown; Figure 5 A scanning electron microscope image of a third type of cerium oxide abrasive grain provided in Comparative Example 3 of this application is shown; Figure 6 A scanning electron microscope image of a fourth type of cerium oxide abrasive grain provided in Comparative Example 4 of this application is shown; Figure 7 A scanning electron microscope image of the fifth type of cerium oxide abrasive grains provided according to Embodiment 5 of this application is shown; Figure 8 A scanning electron microscope image of a sixth type of cerium oxide abrasive grain provided according to Embodiment 6 of this application is shown; Figure 9 A scanning electron microscope image of a seventh type of cerium oxide abrasive grain provided according to Embodiment 7 of this application is shown. Detailed Implementation

[0019] The following description provides specific application scenarios and requirements for this specification, intended to enable those skilled in the art to make and use the contents of this specification. Various partial modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of this specification. Therefore, this specification is not limited to the embodiments shown, but rather to the widest scope consistent with the claims.

[0020] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not restrictive. For example, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” used herein may also include the plural forms. When used in this specification, the terms “comprising,” “including,” and / or “containing” mean that the associated integers, steps, operations, elements, and / or components are present, but do not exclude the presence of one or more other features, integers, steps, operations, elements, components, and / or groups, or that other features, integers, steps, operations, elements, components, and / or groups may be added to the system / method.

[0021] In this application, "X includes at least one of A, B, or C" means that X includes at least A, or X includes at least B, or X includes at least C. That is, X can include any combination of A, B, and C, or any combination of A, B, and C, as well as other possible content / elements. The arbitrary combination of A, B, and C can be A, B, C, AB, AC, BC, or ABC.

[0022] Considering the following description, these and other features of this specification, as well as the operation and function of related structural elements, and the economy of assembly and manufacture of components, can be significantly improved. This description also includes all figures and text in the accompanying drawings, all of which form part of this specification. However, it should be clearly understood that the drawings are for illustrative and descriptive purposes only and are not intended to limit the scope of this specification. It should also be understood that the drawings are not drawn to scale.

[0023] In the field of chemical mechanical polishing, cerium oxide is widely used as a high-performance polishing abrasive due to its excellent chemical activity and moderate hardness, especially suitable for the ultra-precision machining of high-value-added materials such as optical glass, liquid crystal display substrates, and semiconductor wafers. Ideal cerium oxide abrasives should have regular morphology and high sphericity to ensure stable material removal rate, low surface roughness, and no scratch defects during polishing.

[0024] However, in the homogeneous precipitation process using urea as a precipitant, urea needs to undergo thermal decomposition to slowly release OH-. - To increase the pH of the system and precipitate trivalent cerium ions with carbonate, thereby promoting the precipitation of Ce 3+ / Ce 4+ Hydrolysis produces cerium oxide precursors. The decomposition rate of urea is highly dependent on local temperature and concentration distribution; the presence of micro-temperature differences or uneven mixing within the reactor can lead to OH- decomposition. - The release rate is spatially inconsistent, which leads to asynchronous and non-uniform nucleation—nucleation occurs prematurely in some areas, forming a large number of small particles, while nucleation is delayed in other areas, ultimately resulting in inconsistent abrasive morphology.

[0025] Meanwhile, due to the low viscosity of the reaction system itself and the lack of effective steric hindrance or electrostatic stabilization mechanisms, the newly generated cerium oxide nanoparticles have high surface energy and intense Brownian motion, making them prone to collisions and particle fusion after nucleation. The high surface energy drives the dissolution of small particles and the growth of large particles, or causes adjacent particles to fuse at the contact point, forming irreversible hard aggregates and destroying the spherical structure.

[0026] To improve the morphology of cerium oxide abrasive grains and achieve high sphericity, this application provides a method for preparing cerium oxide abrasive grains and the cerium oxide abrasive grains themselves. A thickener with a high Fikentscher K value is added to the reaction system. The thickener forms a dense protective layer with a certain steric hindrance effect around the cerium oxycarbonate precursor particles, effectively inhibiting mutual collisions, aggregation, and anisotropic growth of the cerium oxycarbonate precursor particles during nucleation and growth. The thickener acts as a capping agent, preventing the cerium oxycarbonate precursor particles from fusing together, thereby avoiding the formation of rod-shaped or ultra-large cerium oxide particles and agglomerates. This thickener does not participate in condensation or cross-linking reactions. Simultaneously, the high-K-value thickener significantly increases the overall viscosity of the reaction system, reduces the particle migration rate, thereby slowing down crystal growth kinetics, promoting isotropic growth, and facilitating the formation of precursor particles with regular morphology and high sphericity. The cerium oxide abrasive grains obtained after subsequent calcination treatment maintain a regular spherical morphology, thereby improving the performance consistency and surface finish of cerium oxide abrasive grains in precision polishing applications.

[0027] In a first aspect, embodiments of this application provide a method for preparing cerium oxide abrasive particles. Figure 1 A flowchart illustrating a method for preparing cerium oxide abrasive particles according to an embodiment of this application is shown. Figure 1 As shown, the method P100 for preparing cerium oxide abrasive particles may include steps S110 and S120.

[0028] S110: A thickener with a high K value (Fikentscher K value) is added to the reaction system, and cerium oxycarbonate precursor particles are synthesized. The thickener forms a protective layer around the cerium oxycarbonate precursor particles, inhibiting the aggregation and anisotropic growth of the cerium oxycarbonate precursor particles.

[0029] The K-value (Fikentscher K-value) is an empirical parameter used to characterize the viscosity properties of water-soluble polymers in dilute solutions. It was proposed by the German scientist Fikentscher. The K-value is calculated by measuring the relative viscosity of a polymer aqueous solution of a certain concentration under standard conditions and then substituting the values ​​into a specific empirical formula. A higher K-value indicates a stronger thickening ability and a more significant steric hindrance effect in the solution. The K-value (Fikentscher K-value) is often abbreviated as K-value.

[0030] Cerium oxycarbonate precursor particles are intermediate phases formed during the synthesis of cerium oxide abrasive particles. These particles are compounds containing cerium, oxygen, and carbonate ions, and their chemical composition is typically represented as Ce(OH). x (CO3) y · n H2O or similar forms.

[0031] A high-K-value thickener was added to the reaction system to synthesize cerium oxycarbonate precursor particles. The thickener formed a protective layer around the cerium oxycarbonate precursor particles, inhibiting their aggregation and anisotropic growth. Specifically, after introducing a high-K-value thickener into the reaction system, the thickener not only increased the viscosity of the system in solution but also coated the surface of the newly formed cerium oxycarbonate precursor particles through physical adsorption or weak interactions, forming a protective layer with steric hindrance. This protective layer effectively isolates adjacent particles, inhibiting collisions and aggregation caused by Brownian motion during the early stages of nucleation and growth. Furthermore, the protective layer uniformly covers the active sites on the particle surface, hindering the preferential growth of specific crystal faces, thereby suppressing anisotropic development (such as the formation of non-spherical morphologies like plates and rods), promoting uniform particle growth in all directions, and ultimately resulting in a cerium oxycarbonate precursor with regular morphology, high sphericity, and good dispersibility.

[0032] Thickeners are functional polymeric additives that can significantly increase the viscosity of solution systems. The long-chain molecular structure of thickeners fully extends in the solvent, forming an intertwined network structure, thereby increasing the internal frictional resistance of the solution. Thickeners can include at least one of synthetic water-soluble polymers, cellulose derivatives, or natural or modified polysaccharide polymers. Thickeners are nonionic. Nonionic cellulose derivatives are obtained by chemical modification of natural cellulose and possess good water solubility, film-forming properties, and thickening ability. The molecular chains of cellulose derivatives are rich in hydroxyl and carboxyl groups, which can weakly interact with cerium oxycarbonate precursor particles, contributing to stable particle dispersion. Cellulose derivatives may include at least one of hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), methyl cellulose (MC), or hydroxypropyl methyl cellulose (HPMC).

[0033] Nonionic natural or modified polysaccharide polymers are derived from biological resources and have advantages such as environmental friendliness and biodegradability. Natural or modified polysaccharide polymers contain a large number of polar groups, which can form high-viscosity solutions in water and inhibit particle aggregation through steric hindrance. Natural or modified polysaccharide polymers may include at least one of guar gum, gum arabic, or starch and its modified forms.

[0034] Nonionic synthetic water-soluble polymers possess well-defined chemical structures and tunable molecular weights, allowing for effective modification of particle surfaces and precise control of system viscosity through adjustment of chain length and functional groups. Synthetic water-soluble polymers may include at least one of the following: polyvinylpyrrolidone (PVP), polyvinylpyrrolidone-vinyl acetate copolymer (PVP / VA), polyvinylcaprolactam (PVCL), polyvinylpiperidone, poly(N-vinylacetamide) (PNVA), polyacrylamide (PAM), poly(N,N-dimethylacrylamide) (PDMA), polyoxazoline polymers (e.g., poly(2-ethyl-2-oxazoline)), polyethylene glycol (PEG), or polyvinyl alcohol (PVA). In a preferred embodiment, the thickener is polyvinylpyrrolidone (PVP).

[0035] In a preferred embodiment, the polyvinylpyrrolidone (PVP) has a high K value. PVP with varying K values ​​is commercially available. Specifically, in some embodiments, the K value of PVP ranges from 30 to 120. PVP within this range effectively improves the roundness and particle size uniformity of cerium oxide abrasive particles during preparation. Specifically, during the preparation of cerium oxide abrasive particles, PVP can indirectly optimize the roundness and particle size uniformity of the final cerium oxide (CeO2) abrasive particles by controlling the morphology of the cerium oxycarbonate precursor particles. During the cerium oxycarbonate precursor particle synthesis stage, PVP molecules coordinate with cerium nanoparticles through pyrrolidone rings, selectively adsorbing onto high-energy crystal planes, inhibiting anisotropic growth, and promoting the formation of spherical, monodisperse cerium oxycarbonate precursor particles. Meanwhile, the long-chain structure of polyvinylpyrrolidone (PVP) provides steric hindrance, preventing particle agglomeration and Ostwald curing. Since cerium oxide abrasive grains are derived from cerium oxycarbonate precursor particles through calcination, the high sphericity and size uniformity of the cerium oxycarbonate precursor particles are effectively inherited, ultimately resulting in high-performance cerium oxide abrasive grains with regular morphology and narrow particle size distribution.

[0036] Specifically, when the K value of polyvinylpyrrolidone (PVP) is in the range of 30-50, PVP exhibits excellent water solubility, dissolving rapidly with low viscosity and good flowability. When the K value of PVP is in the range of 50-80, PVP achieves a good balance between solubility, viscosity, and film-forming properties, resulting in a solution with moderate consistency, flexible film formation, moderate adhesion, and excellent processability. When the K value of PVP is in the range of 80-120, the viscosity of the PVP solution increases significantly, resulting in a tough, elastic film with strong adhesion, but the dissolution rate is slower, usually requiring heating or vigorous stirring.

[0037] In some embodiments, the K value of polyvinylpyrrolidone (PVP) ranges from 50 to 100. More specifically, the K value of PVP is 30-40, 40-50, 50-60, 60-70, 70-80, 80-90, 90-100, 100-110, or 110-120. It is understood that the K value range of PVP can be a combined range of any of the above ranges; for example, the K value range of PVP is 40-90.

[0038] Accordingly, the molecular weight range of polyvinylpyrrolidone is 120,000 g / mol to 1,200,000 g / mol. In some embodiments, the molecular weight range of polyvinylpyrrolidone is 200,000 to 1,000,000 g / mol. Furthermore, the molecular weight of polyvinylpyrrolidone is 100,000 g / mol-120,000 g / mol, 120,000 g / mol-200,000 g / mol, 200,000 g / mol-300,000 g / mol, 300,000 g / mol-400,000 g / mol, 400,000 g / mol-500,000 g / mol, 500,000 g / mol-600,000 g / mol, 600,000 g / mol-700,000 g / mol, 700,000 g / mol-800,000 g / mol, 800,000 g / mol-900,000 g / mol, 900,000 g / mol-1000,000 g / mol, ... g / mol - 1100,000 g / mol, 1100,000 g / mol - 1200,000 g / mol. It is understood that the molecular weight range of polyvinylpyrrolidone can be a combination of any of the above ranges; for example, the molecular weight range of polyvinylpyrrolidone is 120,000 g / mol - 400,000 g / mol.

[0039] The mass concentration of polyvinylpyrrolidone in the reaction system ranges from 0.01 wt% to 20 wt%. In some embodiments, the mass concentration of polyvinylpyrrolidone in the reaction system ranges from 0.1 wt% to 10 wt%. In some embodiments, the mass concentration of polyvinylpyrrolidone in the reaction system ranges from 0.5 wt% to 6 wt%. Furthermore, the mass concentration range of polyvinylpyrrolidone in the reaction system is between 0.01 wt%-0.05 wt%, 0.05 wt%-0.1 wt%, 0.1 wt%-0.5 wt%, 0.5 wt%-1 wt%, 1 wt%-2 wt%, 2 wt%-4 wt%, 4 wt%-6 wt%, 6 wt%-8 wt%, 8 wt%-10 wt%, 10 wt%-12 wt%, 12 wt%-14 wt%, 14 wt%-16 wt%, 16 wt%-18 wt%, and 18 wt%-20 wt%. It is understood that the above-mentioned mass concentration ranges of polyvinylpyrrolidone in the reaction system can be arbitrarily combined; for example, the mass concentration range of polyvinylpyrrolidone in the reaction system is 4 wt%-12 wt%.

[0040] After adding a thickener to the reaction system, cerium oxycarbonate precursor particles can be synthesized. Among them, Figure 2 A flowchart illustrating a method for synthesizing cerium oxycarbonate precursor particles according to an embodiment of this application is shown. Figure 2 As shown, the synthesis method P200 of cerium oxycarbonate precursor particles includes steps S210 and S220.

[0041] S210: Urea and soluble cerium salt are added to the reaction system, and the urea is heated and decomposed to generate carbonate under a preset heating time.

[0042] Urea and a soluble cerium salt are added to a solvent containing polyvinylpyrrolidone to form a homogeneous solution. The solution is then heated. Urea undergoes a controlled thermal decomposition process, gradually generating carbonates. Specifically, under heating conditions, urea undergoes primary decomposition to generate isocyanate. The chemical reaction is shown in (1): (1) After obtaining isocyanate, it rapidly hydrolyzes in the presence of water to produce NH4. + The chemical reaction with CO2 is shown in (2) and (3): (2) (3) As the reaction proceeds, carbonate ions (CO3) in the solution... 2- ) and / or bicarbonate (HCO3) - As the concentration of NH4⁺ gradually increases, the release of NH4⁺ causes the pH of the system to rise slowly. The pH value rises from acidic to weakly alkaline.

[0043] In the above reaction, the solvent can accommodate urea, cerium salts, and other components such as thickeners to suspend these components in the solvent. The solvent can be water or a mixture of water-compatible solvents. Pure water is an ideal medium for dissolving cerium salts and urea due to its high polarity, good solubility, and environmental friendliness. Introducing polyol co-solvents such as ethanol, ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, or glycerol can effectively regulate the viscosity, surface tension, and boiling point of the system, slow down reaction kinetics, inhibit particle agglomeration, and promote isotropic growth through the weak coordination of hydroxyl groups with metal ions, thereby improving the sphericity and dispersibility of cerium oxide particles. When the solvent is a combination of multiple components, the solvent contains at least 50 wt% water, for example, 50 wt%, 70 wt%, 90 wt%, 95 wt%, or 99 wt% water. Furthermore, the water is deionized water.

[0044] Urea (CO(NH2)2) is introduced into a solvent containing soluble cerium salts as a key homogeneous precipitant. Upon heating, urea first thermally decomposes to produce isocyanate (HNCO) and ammonia (NH3). Subsequently, the isocyanate rapidly hydrolyzes to form ammonium carbonate, releasing carbonate ions (CO3-). 2- ) and ammonium ions (NH4+) + This allows the system's pH to rise slowly and uniformly. This slow-release mechanism avoids local supersaturation and promotes the release of Ce from the soluble cerium salt. 3+ The urea reacts smoothly with carbonate ions to generate cerium oxycarbonate precursor particles with regular morphology and uniform particle size, laying the foundation for subsequent calcination to obtain cerium oxide (CeO2) abrasive particles with high roundness and narrow distribution. Therefore, urea not only provides the anions required for precipitation in this process, but also achieves precise control over particle nucleation and growth kinetics through its controllable decomposition characteristics.

[0045] The molar concentration of urea in the reaction system ranges from 0.03 mol / L to 50 mol / L. In some embodiments, the molar concentration of urea in the reaction system ranges from 0.03 mol / L to 20 mol / L. In some embodiments, the molar concentration of urea in the reaction system ranges from 0.03 mol / L to 4.8 mol / L. Further, the molar concentration of urea in the reaction system ranges from 0.03 mol / L to 1 mol / L, 1 mol / L to 5 mol / L, 5 mol / L to 10 mol / L, 10 mol / L to 15 mol / L, 15 mol / L to 20 mol / L, 20 mol / L to 25 mol / L, 25 mol / L to 30 mol / L, 30 mol / L to 35 mol / L, 35 mol / L to 40 mol / L, 40 mol / L to 45 mol / L, and 45 mol / L to 50 mol / L. It is understood that the above-mentioned range of molar concentrations of urea in the reaction system can be arbitrarily combined. For example, the range of molar concentrations of urea in the reaction system is 1 mol / L-25 mol / L.

[0046] S220: The carbonate reacts with the cerium salt to precipitate and form the cerium oxycarbonate precursor particles.

[0047] After obtaining carbonates through the above reactions, the Ce in the soluble cerium salt 3+ The ions can react uniformly with carbonate ions to generate cerium oxycarbonate precursor particles with regular morphology and uniform particle size. The chemical reaction formula is as follows: (4) In this chemical reaction, cerium salts act as soluble Ce. 3+The ion source, possessing high water solubility, strong coordination ability, and a certain tendency to hydrolyze, readily combines with carbonic acid to form a precipitate under alkaline conditions. During the urea-assisted homogeneous precipitation process, NH3 and CO3 are slowly released as urea thermally decomposes. 2- The pH of the system gradually increases, promoting Ce 3+ The cerium oxide particles are uniformly hydrolyzed and transformed into cerium oxycarbonate precursor particles. This process relies on the metal centers provided by the cerium salt and the controllable reaction kinetics between the cerium salt and the decomposition products. It not only determines the nucleation rate and crystal growth direction, but also directly affects the morphology, size distribution, and crystal quality of the final cerium oxide particles. It is a key foundation for achieving the synthesis of cerium oxide abrasive particles with high sphericity.

[0048] Cerium salts can include trivalent and tetravalent cerium salts. Trivalent cerium salts include at least one of cerium(III) nitrate hexahydrate, cerium(III) chloride heptahydrate, anhydrous cerium(III) chloride, cerium(III) sulfate octahydrate, cerium(III) sulfate hydrate, cerium(III) bromide heptahydrate, anhydrous cerium(III) iodide, cerium(III) acetate hydrate, cerium(III) oxalate decahydrate, cerium(III) fluoride, cerium(III) phosphate, and cerium(III) carbonate. Tetravalent cerium salts include at least one of cerium(IV) sulfate tetrahydrate, ammonium cerium(IV) sulfate, ammonium cerium(IV) nitrate, cerium(IV) fluoride, cerium(IV) hydroxide, and cerium(IV) perchlorate. In a particularly preferred embodiment, the cerium salt is cerium(III) nitrate hexahydrate.

[0049] In the synthesis of cerium oxide abrasive grains, increasing the concentration of cerium salt can increase the number of nucleation sites per unit volume, thereby improving the yield of cerium oxide abrasive grains. However, excessively high cerium salt concentrations can disrupt the kinetic balance between nucleation and growth, causing particles to collide, aggregate, and even fuse in a high-density environment, making isotropic growth difficult. Therefore, a suitable cerium salt concentration is fundamental to forming cerium oxide abrasive grains with high sphericity.

[0050] The molar concentration of cerium salt in the reaction system ranges from 0.001 mol / L to 1 mol / L. In some embodiments, the molar concentration of cerium salt in the reaction system ranges from 0.003 mol / L to 0.5 mol / L. In some embodiments, the molar concentration of cerium salt in the reaction system ranges from 0.005 mol / L to 0.2 mol / L. Furthermore, the molar concentration range of cerium salt in the reaction system is 0.001 mol / L - 0.003 mol / L, 0.003 mol / L - 0.005 mol / L, 0.005 mol / L - 0.01 mol / L, 0.01 mol / L - 0.03 mol / L, 0.03 mol / L - 0.05 mol / L, 0.05 mol / L - 0.1 mol / L, 0.1 mol / L - 0.2 mol / L, 0.2 mol / L - 0.3 mol / L, 0.3 mol / L - 0.4 mol / L, 0.4 mol / L - 0.5 mol / L, 0.5 mol / L - 0.6 mol / L, 0.6 mol / L - 0.7 mol / L, 0.7 mol / L - 0.8 mol / L, and 0.8 mol / L - 0.9 mol / L. The concentrations are between 0.05 mol / L and 0.9 mol / L - 1 mol / L. It is understood that the above ranges of molar concentrations of cerium salts in the reaction system can be arbitrarily combined; for example, the range of molar concentrations of cerium salts in the reaction system could be 0.05 mol / L - 0.6 mol / L.

[0051] Adding an appropriate ratio of urea and cerium salt to the solvent is crucial for the controllable synthesis of cerium oxycarbonate precursor particles. Specifically, urea, as a homogeneous precipitant, directly determines the release rate and concentration of alkaline substances and carbonate ions in the system, thereby regulating the kinetics of the precipitation reaction. If the urea ratio is too low, insufficient pH rise or excessively rapid local nucleation can easily lead to large particle size. Conversely, an excessively high ratio may result in numerous nucleations and small particle size. When the molar ratio of urea to cerium salt is controlled within a suitable range, slow and uniform precipitation can be achieved, promoting isotropic growth of crystal nuclei and forming cerium oxycarbonate precursor particles with high sphericity and narrow particle size distribution. This lays the structural foundation for subsequent calcination to obtain high-performance cerium oxide abrasive particles.

[0052] In this chemical reaction, the suitable ratio of urea to cerium salt is in the range of 3-50. In some embodiments, the suitable ratio of urea to cerium salt is in the range of 6-24. Further, the suitable ratio of urea to cerium salt is in the range of 3-6, 6-10, 10-14, 14-16, 16-20, 20-24, 24-26, 26-28, 28-30, 30-34, 34-36, 36-40, 40-44, 44-46, or 46-50.

[0053] It should be noted that the above reactions (1)-(4) are a synergistic reaction system. That is, after the required components (such as soluble cerium salt, polyvinylpyrrolidone and its urea) are mixed in proportion, the solution is heated to a set temperature and maintained for a preset time, and reactions (1) to (4) occur simultaneously in the solution, thereby generating cerium oxycarbonate precursor particles with regular morphology and uniform particle size in situ.

[0054] In the above reactions (1)-(4), a suitable heating temperature can make the thermal decomposition reaction of urea controllable, so that it is gradually converted into isocyanate and further hydrolyzed into ammonium carbonate, thereby slowly and uniformly releasing NH3 and CO3. 2- First, it avoids explosive nucleation caused by a sudden increase in local pH. Second, a suitable heating temperature helps maintain a stable supersaturation, resulting in a moderate nucleation rate. This allows newly formed material to be deposited isotropically on existing nuclei, promoting the growth of spherical particles.

[0055] In the above-described thermal decomposition reaction, the heating temperature range can be 55℃-99℃. In some embodiments, the heating temperature range can be 75℃-95℃. Further, the heating temperature ranges are 55℃-60℃, 60℃-65℃, 65℃-70℃, 70℃-75℃, 75℃-80℃, 80℃-85℃, 85℃-90℃, 90℃-95℃, and 95℃-99℃. It is understood that the above heating temperature ranges can be arbitrarily combined; for example, the heating temperature range can be 70℃-85℃. The preparation process in this embodiment of the invention is carried out at a temperature not exceeding 99℃, and a hydrothermal reaction system is not used. The reason is that if the hydrothermal reaction temperature is too high, the decomposition rate of urea will be too fast. In the aforementioned thermal decomposition reaction, the appropriate reaction time has a decisive influence on the size and morphology of the cerium oxycarbonate precursor particles. If the reaction time is too short, urea decomposition is incomplete, and the system pH and carbonate concentration have not reached effective precipitation levels, resulting in insufficient nucleation, low yield, or even failure to form complete particles. Only within a suitable reaction time window can uniform and stable isotropic slow growth of crystal nuclei be achieved, thereby obtaining cerium oxycarbonate precursor particles with high sphericity, uniform size, and good dispersion. This lays the structural foundation for the subsequent calcination preparation of high-performance cerium oxide abrasives.

[0056] Therefore, a suitable heating decomposition reaction time is defined as a preset time. The preset time can be 1 hour to 72 hours. In some embodiments, the preset time can be 9 hours to 24 hours. Further, the preset time can be 1 hour to 5 hours, 5 hours to 9 hours, 9 hours to 14 hours, 14 hours to 21 hours, 21 hours to 28 hours, 28 hours to 35 hours, 35 hours to 42 hours, 42 hours to 49 hours, 49 hours to 56 hours, 56 hours to 63 hours, or 63 hours to 72 hours. It is understood that the above-mentioned preset time ranges can be arbitrarily combined; for example, the preset time range can be 5 hours to 35 hours.

[0057] Within the aforementioned heating temperature range, appropriate system viscosity plays a crucial role in the roundness and uniformity of cerium oxide particles. Moderate viscosity effectively suppresses disordered movement and collisions of particles during nucleation and growth, reducing agglomeration and fusion. Simultaneously, a higher viscoelastic environment helps to achieve more uniform material deposition, promoting isotropic growth and resulting in regularly shaped spherical particles. Furthermore, suitable viscosity can slow down ion diffusion rates, preventing explosive nucleation caused by localized supersaturation, ensuring controllable nucleus numbers and synchronized growth, ultimately yielding high-performance ceramic powders with narrow particle size distribution and good dispersibility. Too low a viscosity makes it difficult to suppress agglomeration, while too high a viscosity hinders mass transfer and crystallization; therefore, precise control is required to achieve the optimal balance between morphology and performance.

[0058] Therefore, the viscosity of the reaction system is from 1 mPa·s to 100 mPa·s. In some embodiments, the viscosity of the reaction system is from 1 mPa·s to 50 mPa·s. In some embodiments, the viscosity of the reaction system is from 2.5 mPa·s to 20 mPa·s. Furthermore, the viscosity of the reaction system is 1 mPa·s to 2.5 mPa·s, 2.5 mPa·s to 5 mPa·s, 5 mPa·s to 10 mPa·s, 10 mPa·s to 15 mPa·s, 15 mPa·s to 20 mPa·s, 20 mPa·s to 25 mPa·s, 25 mPa·s to 30 mPa·s, 30 mPa·s to 35 mPa·s, 35 mPa·s to 40 mPa·s, 40 mPa·s to 45 mPa·s, 45 mPa·s to 50 mPa·s, 50 mPa·s to 55 mPa·s, 55 mPa·s to 60 mPa·s, 60 mPa·s to 65 mPa·s, 65 mPa·s to 70 mPa·s, 70 mPa·s Up to 75 mPa·s, 75 mPa·s to 80 mPa·s, 80 mPa·s to 85 mPa·s, 85 mPa·s to 90 mPa·s, 90 mPa·s to 95 mPa·s, 95 mPa·s to 100 mPa·s.

[0059] S120: Calcination of cerium oxycarbonate precursor particles yields spherical cerium oxide abrasive grains with a well-rounded morphology.

[0060] After obtaining the cerium oxycarbonate precursor particles, the particles were collected, washed, and dried. Next, the cerium oxycarbonate precursor particles were calcined. During calcination, the cerium oxycarbonate precursor particles decomposed and oxidized to form cerium oxide particles. The chemical reaction is shown in (5):

[0061] Because the cerium oxycarbonate precursor particles have high sphericity and regular shape, the calcined cerium oxide particles are spherical with high sphericity and good morphology. In this embodiment, the calcined product is a powder composed of spherical cerium oxide (CeO2) particles. In some embodiments, this powder can be redispersed in water to form a stable colloidal cerium oxide slurry.

[0062] Calcination temperature has a decisive influence on the morphology, grain size, crystallinity, and dispersibility of cerium oxide particles. Specifically, too low a calcination temperature may lead to incomplete decomposition of cerium oxycarbonate precursor particles or Ce... 3+Incomplete oxidation affects the purity and stability of the product. Excessive calcination temperature, on the other hand, can lead to particle sintering, grain coarsening, and destruction of spherical morphology, resulting in a wider particle size distribution, a decreased specific surface area, and a significant reduction in its redispersibility in water. Therefore, selecting an appropriate calcination temperature is crucial.

[0063] In the above reaction (5), a suitable calcination temperature range can be 300℃-1200℃. In some embodiments, the calcination temperature range can be 500℃-900℃. Further, the calcination temperature range can be 300℃-400℃, 400℃-500℃, 500℃-600℃, 600℃-700℃, 700℃-800℃, 800℃-900℃, 900℃-1000℃, 1000℃-1100℃, or 1100℃-1200℃. It is understood that the above calcination temperature ranges can be arbitrarily combined; for example, the heating temperature range can be 700℃-900℃.

[0064] Furthermore, calcination time has a significant impact on the formation of cerium oxide particles. Specifically, if the calcination time is too short, the cerium oxycarbonate precursor particles may not be fully decomposed and completely oxidized, resulting in residual carbonate, hydroxyl, or Ce³⁺ impurities in the product, affecting crystallinity and chemical stability. Conversely, if the calcination time is too long, it will promote excessive grain growth and interparticle sintering, destroying the original spherical morphology, exacerbating hard agglomeration, reducing specific surface area, and weakening its redispersibility in water. Therefore, a suitable calcination time must be selected while ensuring complete conversion of the cerium oxycarbonate precursor particles to balance high product purity, good crystallinity, morphological integrity, and colloidal stability.

[0065] Therefore, the calcination time range can be 15 min - 10 h. In some embodiments, the calcination time range can be 0.5 h - 10 h. Further, the calcination time range can be 15 min - 0.5 h, 0.5 h - 1 h, 1 h - 1.5 h, 1.5 h - 2 h, 2 h - 2.5 h, 2.5 h - 3 h, 3 h - 3.5 h, 3.5 h - 4 h, 4 h - 4.5 h, 4.5 h - 5 h, 5 h - 5.5 h, 5.5 h - 6 h, 6 h - 6.5 h, 6.5 h - 7 h, 7 h - 7.5 h, 7.5 h - 8 h, 8 h - 8.5 h, 8.5 h - 9 h, 9 h - 9.5 h, or 9.5 h - 10 h. It is understood that the above calcination time ranges can be arbitrarily combined; for example, the calcination time range can be 4 h - 7 h.

[0066] It should be noted that, in some embodiments, monodisperse cerium oxide abrasive grains can be obtained by the above preparation method. In some embodiments, polydisperse cerium oxide abrasive grains can be obtained by the above preparation method. In a preferred embodiment, polydisperse cerium oxide abrasive grains can be obtained by the above preparation method. However, regardless of whether it is monodisperse or polydisperse, the morphology of the cerium oxide abrasive grains is highly regular, exhibiting a spherical morphology with clear outlines and high sphericity.

[0067] It should be further clarified that the terms "spherical" or "globose" used in this article are not limited to perfect spheres in a geometric sense, but rather refer to particles whose overall shape is approximately spherical or near-spherical in a macroscopic manner. These cerium oxide abrasive particles are allowed to have a certain degree of morphological deviation, such as local flattening, angularity, or polyhedral features; their overall shape can still be classified as spherical or near-spherical particles.

[0068] Furthermore, these cerium oxide abrasive grains are typically grown from a stack of multiple grains or crystal regions, rather than a single-crystal structure, thus their surfaces are not ideally smooth. At the microscopic scale, the surface of these cerium oxide abrasive grains can exhibit undulating structures, protrusions, or rough features caused by grain growth, forming a surface morphology with microscopic irregularities. These surface undulations are inherent characteristics of polycrystalline cerium oxide abrasive grains and do not affect their overall spherical or near-spherical appearance.

[0069] The prepared cerium oxide abrasive grains can be cerium oxide abrasive grains doped with impurities. In some embodiments, the cerium dioxide abrasive grains are doped cerium dioxide abrasive grains. Suitable dopants are, for example, metal ions (such as Ca, Mg, Zn, Zr, Sc, Y) or lanthanide elements (such as lanthanum, praseodymium, neodymium, promethium, or samarium). The dopants can be present as impurities in the abrasive grains, and the impurities can originate from the raw materials or starting materials used to prepare the abrasive grains.

[0070] Secondly, embodiments of this application provide cerium oxide abrasive particles. The cerium oxide abrasive particles are prepared using the preparation method described in the first aspect above.

[0071] The following describes the application scenarios of cerium oxide abrasives: The spherical cerium oxide abrasive grains prepared by the above method can be widely used in chemical mechanical polishing (CMP) processes for various semiconductor and optical materials due to their high sphericity, controllable particle size distribution, and excellent chemical activity. Specifically, cerium oxide abrasive grains can be used to polish the following substrate materials: silicon oxide (SiO2), silicon nitride (Si3N4), polycrystalline silicon, monocrystalline silicon, silicon carbide (SiC), gallium arsenide (GaAs), indium phosphide (InP), sapphire (Al2O3), quartz glass, ITO (indium tin oxide) transparent conductive films, and metal interconnect layers such as copper (Cu), tungsten (W), and cobalt (Co). These cerium oxide abrasive grains exhibit highly regular spherical shapes with clear outlines and excellent sphericity, effectively reducing the risk of scratching the substrate material during CMP.

[0072] The following are specific embodiments of the compositions designed according to the above content of this disclosure. It should be understood that the following embodiments are merely illustrative of the preparation method of cerium oxide abrasive grains and the cerium oxide abrasive grains disclosed above. The specific implementation methods and parameters used are only one or more of the numerous parameters and methods described above. Those skilled in the art can use other parameters to prepare cerium oxide abrasive grains according to the above methods without departing from the core spirit of the application.

[0073]

Example 1

[0074] The above solution was transferred to a 5 L liquid-phase reactor and reacted at 85°C for 12 hours to achieve slow thermal decomposition of urea and uniform release of carbonate ions, thereby inducing the formation of well-formed cerium oxycarbonate precursor particles. After the reaction, the suspension was centrifuged at 5000 rpm for 1 hour to separate the precipitate. After discarding the supernatant, the precipitate was washed repeatedly with deionized water at least three times, collecting the solid each time under the same centrifugation conditions, and washing continued until the conductivity of the supernatant was below 1 μS·cm. -1To thoroughly remove residual nitrate ions, ammonium ions, and other soluble byproducts, the resulting wet gel was dried overnight at 60°C in a vacuum drying oven to obtain a dried precursor powder.

[0075] Subsequently, the dried precursor was placed in a muffle furnace and calcined at 750°C for 2 hours in air to completely decompose and oxidize it into spherical cerium oxide (CeO2) abrasive particles. The calcined powder was then ultrasonically dispersed in deionized water to reform a stable colloidal suspension.

[0076] The microstructure of cerium oxide abrasive grains was characterized using a Hitachi S-4800 field emission scanning electron microscope (SEM). Figure 3 A scanning electron microscope (SEM) image of a first type of cerium oxide abrasive grain according to Embodiment 1 of this application is shown. The SEM image of the first type of cerium oxide abrasive grain was taken after the first type of cerium oxide abrasive grain was calcined. Figure 3 As shown, under conditions of polyvinylpyrrolidone (PVP) K value of 90 and heating time of 12 hours, cerium oxide abrasive grains exhibit highly spherical shapes. The surface of the cerium oxide abrasive grains has protrusions and displays a polydisperse particle size distribution. Furthermore, the z-average particle size of the dispersed CeO2 particles was measured to be 214.2 nm by dynamic light scattering (DLS) analysis (Malvern Zetasizer).

[0077] Comparative Example 2 The reaction steps for Comparative Example 2 were exactly the same as those for Example 1. However, in Example 2, the initial concentration of cerium nitrate in the reaction mixture was 0.01 mol / L, and the ratio of urea to cerium nitrate in the initial reaction mixture was 12:1. Also, in this example, polyvinylpyrrolidone (PVP) was not added. The heating time was 3 hours. Figure 4 A scanning electron microscope (SEM) image of a second type of cerium oxide abrasive grain provided in Comparative Example 2 of this application is shown. The SEM image of the second type of cerium oxide abrasive grain was taken after calcination of the second type of cerium oxide abrasive grain. Figure 4 As shown, the cerium oxide abrasive particles obtained under these reaction conditions do not exhibit a spherical shape, but rather resemble platelets. Experimental results indicate that the absence of polyvinylpyrrolidone (PVP) causes the cerium oxide abrasive particles to aggregate and exhibit an irregular morphology.

[0078] Comparative Example 3 The reaction steps for Comparative Example 3 were exactly the same as those for Example 1. However, in Example 3, the initial concentration of cerium nitrate in the reaction mixture was 0.01 mol / L, and the ratio of urea to cerium nitrate in the initial reaction mixture was 12:1. In Example 3, polyvinylpyrrolidone (PVP) was added, and the K value of PVP was 15. The heating time was 3 hours.

[0079] Figure 5 A scanning electron microscope (SEM) image of a third type of cerium oxide abrasive grain provided in Comparative Example 3 of this application is shown. The SEM image of the third type of cerium oxide abrasive grain was taken after calcination of the third type of cerium oxide abrasive grain. Figure 5 As shown, the cerium oxide abrasive particles obtained under these reaction conditions do not exhibit a spherical shape, but rather a blocky shape. Experimental results indicate that polyvinylpyrrolidone (PVP) with a lower K value is difficult to effectively control the particle morphology, causing the obtained cerium oxide abrasive particles to deviate from a spherical shape and exhibit an irregular or polyhedral morphology.

[0080] Comparative Example 4 The reaction steps for Comparative Example 4 were exactly the same as those for Example 1. However, in Example 4, the K value of polyvinylpyrrolidone (PVP) was 150.

[0081] Figure 6 A scanning electron microscope (SEM) image of a fourth type of cerium oxide abrasive grain according to Comparative Example 4 of this application is shown. The SEM image of the fourth type of cerium oxide abrasive grain was taken without calcination. Figure 6 As shown, the cerium oxide abrasive grains obtained under these reaction conditions contain very large rod-shaped particles, with an average size of approximately 5 micrometers, which significantly deviates from the highly spherical, submicron-sized morphology of the particles in Example 1. Experimental results indicate that excessively high PVP K values ​​disrupt the formation mechanism of spherical particles, leading to uncontrolled product morphology and coarsening of the particle size.

[0082]

Example 5

[0083] Figure 7 A scanning electron microscope (SEM) image of a fifth type of cerium oxide abrasive grain according to Embodiment 5 of this application is shown. The SEM image of the fifth type of cerium oxide abrasive grain was taken without calcination. Figure 7 As shown, the cerium oxide abrasive grains obtained under these reaction conditions are spherical, and the surface of the cerium oxide abrasive grains has protrusions. The experimental results show that high-K polyvinylpyrrolidone (PVP) can effectively prepare spherical cerium oxide abrasive grains.

[0084]

Example 6

[0085] Figure 8A scanning electron microscope (SEM) image of a sixth type of cerium oxide abrasive grain provided according to Embodiment 6 of this application is shown. The SEM image of the sixth type of cerium oxide abrasive grain was taken after calcination of the sixth type of cerium oxide abrasive grain. Figure 8 As shown, the cerium oxide abrasive grains obtained under these reaction conditions are spherical, and the surface of the cerium oxide abrasive grains has protrusions. The experimental results show that high-K polyvinylpyrrolidone (PVP) can effectively prepare spherical cerium oxide abrasive grains.

[0086]

Example 7

[0087] Figure 9 A scanning electron microscope image of a seventh type of cerium oxide abrasive grain provided according to Embodiment 7 of this application is shown. Figure 9 As shown, the cerium oxide abrasive particles obtained under these reaction conditions are spherical. Experimental results indicate that high-K polyvinylpyrrolidone (PVP) can effectively prepare spherical cerium oxide abrasive particles with a polydisperse particle size distribution.

[0088]

Example 8

[0089] Table 1

[0090] in conclusion: Compared to A1, E1-E7 have higher K values ​​of polyvinylpyrrolidone (PVP), indicating that adding polyvinylpyrrolidone (PVP) with lower K values ​​would result in non-spherical cerium oxide abrasive grains and excessively large Z-average particle size of the formed cerium oxide abrasive grains.

[0091]

Example 9

[0092] Table 2

[0093] in conclusion: The molecular weight and viscosity of polyvinylpyrrolidone (PVP) that are too low (A2, A3) or too high (A4) are both unfavorable for the formation of spherical ceramic particles: the former leads to morphology loss due to insufficient stabilization, while the latter hinders mass transfer due to excessively high solution viscosity, resulting in heterogeneous nucleation and anisotropic growth.

[0094] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0095] In summary, after reading this detailed disclosure, those skilled in the art will understand that the foregoing detailed disclosure may be presented by way of example only and may not be restrictive. Although not explicitly stated herein, those skilled in the art will understand that this specification requires various reasonable changes, improvements, and modifications to the embodiments. These changes, improvements, and modifications are intended to be made by this specification and are within the spirit and scope of the exemplary embodiments described herein.

[0096] Furthermore, certain terms in this specification have been used to describe embodiments of this specification. For example, "an embodiment," "an embodiment," and / or "some embodiments" mean that a particular feature, structure, or characteristic described in connection with that embodiment may be included in at least one embodiment of this specification. Therefore, it is to be emphasized and understood that two or more references to "an embodiment" or "an embodiment" or "alternative embodiment" in various parts of this specification do not necessarily refer to the same embodiment. Moreover, specific features, structures, or characteristics may be suitably combined in one or more embodiments of this specification.

[0097] It should be understood that in the foregoing description of the embodiments in this specification, various features are combined in a single embodiment, drawing, or description for the purpose of simplifying the description and to aid in understanding a feature. However, this does not mean that the combination of these features is necessary, and those skilled in the art may extract some features as individual embodiments when reading this specification. That is, the embodiments in this specification can also be understood as an integration of multiple sub-embodiments. It is also valid when each sub-embodiment contains fewer than all the features of a single foregoing disclosed embodiment.

[0098] Every patent, patent application, publication of a patent application, and other material, such as articles, books, specifications, publications, documents, and literature (excluding any related historical examination documents), cited in this disclosure is incorporated herein for all purposes, including, for example, in the specification and claims of this disclosure. However, in the event of any inconsistency or conflict between the descriptions, definitions, and / or terms used in the foregoing and those used in this disclosure, the descriptions, definitions, and / or terms used in this disclosure shall prevail.

[0099] Finally, it should be understood that the embodiments disclosed herein are illustrative of the principles of the embodiments described in this specification. Other modified embodiments are also within the scope of this specification. Therefore, the embodiments disclosed in this specification are merely examples and not limitations. Those skilled in the art can implement the applications described in this specification using alternative configurations based on the embodiments in this specification. Therefore, the embodiments in this specification are not limited to the embodiments precisely described in the applications.

Claims

1. A method for preparing cerium oxide abrasive particles, characterized in that, include: A thickener with a high K value (Fikentscher K value) is added to the reaction system to synthesize cerium oxycarbonate precursor particles. The thickener forms a protective layer around the cerium oxycarbonate precursor particles to inhibit the aggregation and anisotropic growth of the cerium oxycarbonate precursor particles. The cerium oxycarbonate precursor particles were calcined to obtain spherical cerium oxide abrasive particles with a well-rounded morphology.

2. The preparation method according to claim 1, characterized in that, The thickener is polyvinylpyrrolidone.

3. The preparation method according to claim 2, characterized in that, The K value of the polyvinylpyrrolidone is 30-120.

4. The preparation method according to claim 2, characterized in that, The molecular weight of the polyvinylpyrrolidone is 120,000 g / mol - 1200,000 g / mol.

5. The preparation method according to claim 2, characterized in that, The mass concentration of the polyvinylpyrrolidone in the reaction system ranges from 0.01 wt% to 20 wt%.

6. The preparation method according to claim 1, characterized in that, The synthesized cerium oxycarbonate precursor particles undergo the following reaction under heating for a preset time: Urea and soluble cerium salt are added to the reaction system. The urea is decomposed by heat and then hydrolyzed to generate carbonate. The carbonate reacts with the cerium salt to precipitate and form the cerium oxycarbonate precursor particles.

7. The preparation method according to claim 6, characterized in that, The heating temperature range is 55℃-99℃.

8. The preparation method according to claim 7, characterized in that, Within the heating temperature range, the viscosity of the reaction system is from 1 mPa·s to 100 mPa·s.

9. The preparation method according to claim 6, characterized in that, The preset time is 1 hour to 72 hours.

10. The preparation method according to claim 1, characterized in that, The calcination temperature range is 300℃-1200℃.

11. The preparation method according to claim 1, characterized in that, The calcination time is 15 min - 10 h.

12. The preparation method according to claim 1, characterized in that, The cerium oxide abrasive grains have a polydisperse particle size distribution.

13. A type of cerium oxide abrasive, characterized in that, The cerium oxide abrasive particles are prepared using the preparation method described in any one of claims 1-12.

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