Novel high-cutting low-abrasion sapphire polishing powder and preparation method thereof

Abstract

The invention relates to the technical field of fine chemical materials, in particular to novel high-cutting low-abrasion sapphire polishing powder and a preparation method thereof.The novel high-cutting low-abrasion sapphire polishing powder is prepared by selecting high-purity aluminum oxide as a raw material through mechanical activation, surface modification, staged heat treatment and grading processes. The obtained polishing powder has the characteristics of high cutting efficiency, low abrasion rate, controllable particle size, excellent dispersity, chemical stability and the like. By optimizing the powder morphology, hardness distribution and a modification process, the polishing quality and efficiency are remarkably improved, the problems that traditional polishing powder is low in cutting efficiency, high in abrasion rate and the like are solved, and the polishing powder is suitable for the field of efficient polishing of sapphire, optical glass and semiconductor materials.

Description

Technical Field

[0001] This invention belongs to the field of materials processing and precision manufacturing technology, specifically a novel high-cutting-value, low-wear sapphire polishing powder and its preparation method. Background Technology

[0002] Sapphire, due to its superior physical and chemical properties, including high hardness, excellent chemical stability, and outstanding optical characteristics, is widely used in optical device manufacturing, semiconductor material processing, and other high-end technology fields. However, in the precision machining of sapphire materials, polishing is a crucial step in ensuring that its surface quality reaches nanometer or even sub-nanometer levels of smoothness. Traditional polishing powders face numerous technical bottlenecks in sapphire polishing applications. These problems not only limit the improvement of polishing efficiency but also significantly impact the quality and consistency of the final product.

[0003] Specifically, the main shortcomings of existing polishing powders are as follows: First, traditional polishing powders have low cutting efficiency, resulting in excessively long polishing times, which cannot meet the demands of modern industry for high-efficiency production. Second, polishing powders have a high wear rate during use, which not only increases material consumption costs but may also lead to rapid degradation of powder performance during polishing, thus affecting the stability of the polishing effect. Third, traditional polishing powders have poor dispersibility and are prone to agglomeration when mixed with polishing slurry, leading to unevenness of the polished surface and making it difficult to achieve high-precision polishing requirements. Furthermore, traditional polishing powders lack chemical stability in acidic or alkaline environments, easily experiencing performance degradation, further shortening their service life and increasing maintenance costs. These problems make it difficult for traditional polishing powders to meet the stringent requirements of high-precision polishing of high-hardness materials such as sapphire. Summary of the Invention

[0004] Therefore, to address the aforementioned technical challenges, this invention has developed a novel high-cutting-efficiency, low-wear sapphire polishing powder by optimizing material composition and preparation processes. This polishing powder uses high-purity alumina as the main raw material and achieves a comprehensive improvement in powder performance through refined ball milling, surface modification, heat treatment, and grading processes. Regarding cutting efficiency, optimized design of powder hardness and morphology significantly improves the material's cutting ability, thereby greatly shortening polishing time. In terms of wear rate control, precise control of surface modification and particle size distribution effectively reduces material loss during polishing, extending the service life of the polishing powder. Furthermore, this polishing powder possesses excellent dispersibility and chemical stability, maintaining stable performance even in complex environments, while its narrow particle size distribution further enhances polishing precision and surface finish. In summary, this invention aims to overcome the shortcomings of existing polishing powders in terms of cutting efficiency, wear rate, dispersibility, and chemical stability, providing an innovative solution for the efficient and precise polishing of sapphire and other high-hardness materials.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for efficiently preparing sapphire polishing powder, comprising the following steps:

[0007] Raw material selection and pretreatment: High-purity alumina (content ≥99.98%) is selected, and impurity particles are removed by sieving to ensure the purity of the raw materials.

[0008] Mechanical activation: The raw materials are placed in a ball mill for mechanical activation treatment. The particle size and morphology of the powder are optimized by adjusting the ball-to-material ratio, rotation speed and time.

[0009] Surface modification: The powder is treated with a composite surface modifier to enhance its dispersibility and wear resistance. The modifier can be an organosilicon compound or a metal alkoxide, and the addition amount is 0.2%-0.6%.

[0010] Heat treatment process: The modified powder is heat-treated at a specific temperature. The first stage removes surface adsorbed moisture at low temperature, and the second stage promotes crystal phase transformation at high temperature, further improving the machinability of the powder.

[0011] Grading and Packaging: Powders within the target particle size range are screened using air classifying or centrifugal classification processes and then vacuum-sealed for moisture protection to ensure storage stability.

[0012] To verify the technical effects of the present invention, the following embodiments and comparative examples were designed for comparative testing:

[0013] Example 1:

[0014] Raw material: High-purity alumina (content ≥ 99.99%).

[0015] Mechanical activation: ball milling time 10 hours, speed 350 rpm, ball-to-material ratio 10:1.

[0016] Surface modifier: organosilicon compound, added at 0.4%.

[0017] Heat treatment: First stage: 200℃ for 1 hour, second stage: 1000℃ for 2 hours.

[0018] Grading: Target particle size range 0.5-1.0μm.

[0019] Example 2:

[0020] Raw material: High-purity alumina (content ≥ 99.98%).

[0021] Mechanical activation: ball milling time 12 hours, speed 300 rpm, ball-to-material ratio 12:1.

[0022] Surface modifier: metal alkoxide, addition amount 0.5%.

[0023] Heat treatment: First stage: 250℃ for 1.5 hours; Second stage: 1100℃ for 3 hours.

[0024] Grading: Target particle size range 1.0-2.0μm.

[0025] Comparative Example 1:

[0026] Raw material: Ordinary alumina (content ≥99.5%).

[0027] No surface modification treatment was performed.

[0028] Heat treatment: Hold at 900℃ for 2 hours.

[0029] Comparative Example 2:

[0030] Raw material: High-purity alumina (content ≥ 99.98%).

[0031] Mechanical activation: ball milling time 8 hours, speed 400 rpm, ball-to-material ratio 8:1.

[0032] Surface modifier: Single silane coupling agent, added at 0.3%.

[0033] Heat treatment: Hold at a single temperature of 1000℃ for 2 hours.

[0034] Performance comparison table:

[0035] index Example 1 Example 2 Comparative Example 1 Comparative Example 2 Test methods Alumina content (%) ≥99.99 ≥99.98 ≥99.5 ≥99.98 X-ray fluorescence spectroscopy analysis Cutting efficiency (μm / min) ≥0.5 ≥0.4 ≤0.2 ≤0.3 Cutting efficiency tester Wear rate (%) ≤0.1 ≤0.2 ≥0.5 ≥0.4 Wear rate tester Particle size distribution (μm) 0.5-1.0 1.0-2.0 Uneven 0.8-1.5 Laser particle size analyzer <![CDATA[Specific surface area (m 2 / g)]]> 5.0-6.0 4.0-5.0 3.0-4.0 3.5-4.5 BET method <![CDATA[Bulk density (g / cm 3 )]]> 0.8-1.0 0.9-1.1 0.6-0.8 0.7-0.9 Tap density tester pH value 6.5-7.5 6.0-7.0 5.0-6.0 5.5-6.5 pH meter Moisture content (%) ≤0.1 ≤0.2 ≥0.5 ≥0.3 Karl Fischer

[0036] Furthermore, this application also proposes a sapphire polishing powder, as shown in Examples 1 and 2. The polishing powder is prepared by a highly efficient method for preparing sapphire polishing powder. The alumina content of the polishing powder is not less than 99.98%, the particle size ranges from 0.5 to 2 μm, and the specific surface area of ​​the polishing powder is from 4 to 6 m². 2 The bulk density of the polishing powder is between 0.8 and 1.1 g / cm³. 3 The polishing powder has a moisture content of no more than 0.2%, a pH value between 6 and 7.5, and is highly dispersed in the polishing liquid after surface modification.

[0037] Compared with the prior art, the beneficial effects of the present invention are:

[0038] (1) High cutting efficiency: By optimizing the powder morphology and hardness distribution, the cutting ability of the polishing powder is significantly improved and the polishing time is shortened.

[0039] (2) Low wear rate: The use of composite surface modifier combined with segmented heat treatment process greatly reduces the wear of polishing powder during use and extends its service life.

[0040] (3) Excellent dispersibility: After modification, the powder exhibits high dispersibility in the polishing liquid, reducing agglomeration and improving polishing uniformity.

[0041] (4) Chemical stability: It can maintain stable performance under high temperature, acid or alkaline environment, and is suitable for a variety of complex polishing scenarios.

[0042] (5) Uniform particle size: The particle size of the powder is precisely controlled by the grading process, which improves the polishing accuracy and surface smoothness and meets the requirements of high-precision polishing. Attached Figure Description

[0043] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0044] In the attached diagram:

[0045] Figure 1 This is a flowchart illustrating the steps involved in preparing a novel high-cutting-value, low-wear sapphire polishing powder. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0048] This invention provides a novel high-cutting-value, low-wear sapphire polishing powder and its preparation method, combined with the attached... Figure 1 The flowchart of the steps is provided, and the specific implementation method is explained in detail.

[0049] Appendix Figure 1 The entire process flow, from raw material selection and pretreatment to final grading and packaging, was demonstrated, including key steps such as mechanical activation, surface finishing, and heat treatment. By optimizing the parameters and process conditions of each step, the performance of the polishing powder can be significantly improved to meet the requirements of high-precision polishing.

[0050] In the specific implementation process, the first step is the selection and pretreatment of raw materials. High-purity alumina is selected as the main raw material, with an Al□O3 content of over 99.98% to ensure the chemical stability and physical properties of the final product. After the raw materials are sieved to remove impurities, they enter the mechanical activation process. Mechanical activation is a process of processing the raw materials using a ball mill to optimize the grain size and morphology of the powder. (See attached...) Figure 1 In the mechanical activation steps shown, ball milling time, rotation speed, and ball-to-powder ratio are key control parameters. For example, in Example 1, the ball milling time is 10 hours, the rotation speed is 350 rpm, and the ball-to-powder ratio is 10:1; while in Example 2, the ball milling time is extended to 12 hours, the rotation speed is adjusted to 300 rpm, and the ball-to-powder ratio is increased to 12:1. The adjustment of these parameters directly affects the hardness distribution of the powder and the cutting efficiency.

[0051] After mechanical activation, the powder enters the surface modification process. Surface modification involves treating the powder with a composite surface modifier to enhance its dispersibility and wear resistance. The selection and dosage of the modifier are key technical aspects of this process. In Example 1, an organosilicon compound was used as the modifier, with an addition amount of 0.4% of the powder mass; while in Example 2, a metal alkoxide was used as the modifier, with an addition amount of 0.5%. The modifier's mechanism of action lies in its ability to form a uniform protective film on the powder surface, thereby reducing the powder's own loss during use. Furthermore, the modifier can improve the powder's dispersibility in the polishing slurry, thus reducing agglomeration. The specific steps of this process include: mixing the modifier with the powder and stirring thoroughly to ensure the modifier uniformly covers the powder surface, followed by standing to ensure the modification effect.

[0052] The next step is the heat treatment process, a crucial step in preparing high-cutting-performance, low-wear sapphire polishing powder. This process consists of two stages. The first stage is a low-temperature dehydration treatment to remove adsorbed moisture from the powder surface, preventing it from affecting subsequent high-temperature processing. In Example 1, the first-stage heat treatment temperature was 200°C, and the holding time was 1 hour; in Example 2, the temperature was increased to 250°C, and the holding time was extended to 1.5 hours. The second stage is a high-temperature phase transformation treatment, which promotes the optimization of the powder's internal structure through high temperature, further improving its cutting performance. In Example 1, the second-stage heat treatment temperature was 1000°C, and the holding time was 2 hours; in Example 2, the temperature was increased to 1100°C, and the holding time was extended to 3 hours. Precise control of temperature and time during the heat treatment process is crucial to the powder's performance; excessively high or low temperatures will affect the powder's hardness and chemical stability.

[0053] After heat treatment, the powder enters the grading process. The grading process uses airflow classification or centrifugal classification to screen powders within the target particle size range, ensuring uniform material removal during polishing. In Example 1, the target particle size range is 0.5-1.0 μm; in Example 2, the target particle size range is expanded to 1.0-2.0 μm. Precise control of the grading process can significantly improve the surface finish and polishing accuracy of the polishing powder. Furthermore, the graded powder is vacuum-sealed for moisture protection to ensure stability during storage.

[0054] The sapphire polishing powder prepared by this method has the following advantages:

[0055] High cutting efficiency: By optimizing the powder morphology and hardness distribution, the ability of polishing powder to remove material per unit time is greatly improved, shortening the polishing cycle.

[0056] Low wear rate: The unique surface finishing process effectively reduces the wear of the polishing powder during use, extending its service life.

[0057] Particle size controllability: The particle size range of the powder is precisely controlled through a grading process, ensuring uniform material removal during polishing and a higher surface finish.

[0058] Excellent dispersibility: After special modification treatment, the powder can be highly dispersed in the polishing liquid, avoiding agglomeration and improving the polishing effect.

[0059] Chemical stability: It maintains stable performance in acidic or alkaline environments, making it suitable for a variety of complex polishing scenarios.

[0060] To verify the technical effects of the present invention, this application designed multiple embodiments and comparative examples for comparative testing. Embodiment 1 and Embodiment 2 adopted different process parameters, while Comparative Example 1 and Comparative Example 2 did not adopt the optimized process of the present invention.

[0061] The advantages of this invention are clearly evident from the testing of various performance indicators. For example, in terms of cutting efficiency, Example 1 achieves a cutting efficiency of over 0.5 μm / min, while Comparative Example 1 is only below 0.2 μm / min; in terms of wear rate, Example 1 has a wear rate of less than 0.1%, while Comparative Example 1 has a wear rate of over 0.5%. These data indicate that this invention significantly improves the cutting ability and service life of polishing powder by optimizing powder morphology, hardness distribution, and surface modification processes.

[0062] In practical applications, the sapphire polishing powder of this invention can be widely used for efficient polishing in fields such as optical devices, semiconductors, and high-end screens. For example, in the polishing process of sapphire screens, traditional polishing powders often suffer from problems such as low cutting efficiency and poor surface finish, while the polishing powder of this invention can effectively solve these problems through its excellent dispersibility and particle size uniformity. In addition, due to its strong chemical stability, it can maintain stable performance in acidic or alkaline environments, thus making it suitable for a variety of complex polishing scenarios.

[0063] To further illustrate the operating principle and process of this invention, the following description is in conjunction with the appendix. Figure 1 The various processes in the process are described in detail.

[0064] In the raw material selection and pretreatment stage, high-purity alumina, after sieving, enters the mechanical activation process, where the high-speed rotation of a ball mill refines the powder grains and optimizes its morphology. Subsequently, the powder enters the surface modification process, where a modifier is evenly coated onto the powder surface during stirring, forming a protective film. Next, the powder enters the heat treatment process; the first stage of low-temperature dehydration removes surface moisture, while the second stage of high-temperature phase transformation optimizes the internal structure of the powder. Finally, the classification process uses airflow classification or centrifugal classification to screen powders within the target particle size range, and then vacuum-packs them for moisture protection.

[0065] In the above process flow, the mechanical activation time and rotation speed need to be adjusted according to the initial state of the powder to ensure that the grain size and morphology of the powder reach the optimal state. In the surface modification process, the type and amount of modifier added need to be selected according to the application and performance requirements of the powder to achieve the best modification effect. In the heat treatment process, precise control of temperature and time can significantly affect the hardness and chemical stability of the powder. In the classification process, the selection of the target particle size range needs to be adjusted according to the specific polishing requirements to ensure uniform material removal and surface smoothness during the polishing process.

[0066] In summary, by optimizing the raw material composition, modification process, and processing conditions, this invention has developed a sapphire polishing powder that combines high cutting efficiency and low wear rate, significantly improving polishing quality and efficiency.

[0067] The above description is a detailed description of the preferred embodiments of the present invention. However, the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modifications made under the technical spirit of the present invention should fall within the patent scope covered by the present invention.

Claims

1. A method for preparing a novel high-cutting and low-abrasion sapphire polishing powder, characterized in that, The method comprises the following steps: Step 1: high-purity alumina with alumina content not less than 99.98% is selected and screened to remove impurity particles; Step 2: the pretreated raw material is placed in a ball mill for ball milling treatment, the ball milling time is between 8 to 12 hours, the rotating speed is between 300 to 350 rpm, and the ball-to-material ratio is between 8:1 to 12:1; Step 3: a composite surface modifier is used to treat the mechanically activated powder, the modifier is an organic silicon compound or a metal alkoxide, and the addition amount is 0.2% to 0.6% of the mass of the powder; Step 4: the surface-modified powder is subjected to staged heat treatment, the first stage is at 200 to 250℃ for 1 to 1.5 hours, and the second stage is at 1000 to 1100℃ for 2 to 3 hours; Step 5: the powder within the target particle size range is screened through airflow classification or centrifugal classification process and is vacuum moisture-proof packaged.

2. The preparation method of the novel high-cutting and low-abrasion sapphire polishing powder according to claim 1, characterized in that, When the composite surface modifier is an organic silicon compound, the addition amount is 0.4% of the mass of the powder.

3. The preparation method of the novel high-cutting and low-abrasion sapphire polishing powder according to claim 1, characterized in that, When the composite surface modifier is a metal alkoxide, the addition amount is 0.5% of the mass of the powder.

4. The preparation method of the novel high-cutting and low-abrasion sapphire polishing powder according to claim 1, characterized in that, The ball milling time is 10 hours, the rotating speed is 350 rpm, and the ball-to-material ratio is 10:

1.

5. The method of claim 1, wherein the method of preparing a novel high cutting and low abrasion sapphire polishing powder is characterized by, The ball milling time is 12 hours, the rotating speed is 300 rpm, and the ball-to-material ratio is 12:

1.

6. The method of claim 1, wherein the method of preparing a novel high cutting and low abrasion sapphire polishing powder is characterized by, The target particle size range is 0.5 to 1 μm.

7. The method of claim 1, wherein the method is characterized by: The target particle size range is 1 to 2 μm.

8. The method of claim 1, wherein the method is characterized by: The first stage temperature of the heat treatment is 200℃, the holding time is 1 hour, the second stage temperature is 1000℃, and the holding time is 2 hours.

9. The method of claim 1, wherein the method is characterized by: The first stage temperature of the heat treatment is 250℃, the holding time is 1.5 hours, the second stage temperature is 1100℃, and the holding time is 3 hours.

10. A sapphire polishing powder, characterized by, The polishing powder is prepared by the method of any one of claims 1 to 9, the polishing powder has an alumina content not less than 99.98%, the particle size range of the polishing powder is 0.5 to 2 μm, the specific surface area of the polishing powder is between 4 to 6 m2 / g, the bulk density of the polishing powder is between 0.8 to 1.1 g / cm2, the moisture content of the polishing powder is not more than 0.2%, and the pH value of the polishing powder is between 6 to 7.5.

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