Grading method for powder particles in polishing solution
By placing the absorbance at different heights in the polishing liquid, the relationship between absorbance and height changes is established, and multi-stage liquid separation is carried out, which solves the problems of low accuracy and complex equipment of the existing polishing liquid particle grading methods, and achieves efficient and scientific particle grading.
Patent Information
- Application Number
- CN202411791380.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-06
- Publication Date
- 2025-05-30
AI Technical Summary
The existing polishing liquid particle size grading methods have problems such as low accuracy, complex equipment and high cost, and it is difficult to meet the needs of high-precision grading.
After the polishing liquid is left to stand, part of the suspended solution is taken out at different heights and diluted, its absorbance is measured, the relationship between absorbance and height is established, and the appropriate height point is selected for multi-stage liquid is divided to achieve the grading of powder particles in the polishing liquid.
It realizes efficient grading of polishing liquid particles, which has the advantages of scientificity, simple operation and small particle losses, and is suitable for grading of nano- and micro-scale particles.
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Figure CN120064165A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of polishing liquids, and particularly to a method for classifying powder particles in a polishing liquid. Background Art
[0002] As an indispensable processing material in modern industry, the particle size of a polishing liquid has a direct impact on the processing quality and effect. In the fields of electronics, optics, and metal processing, polishing liquids with different particle sizes have different application scenarios and requirements. For example, ultra-fine polishing liquids with a particle size below 100 nanometers are suitable for the precision processing of chips and semiconductor devices, which can effectively reduce the surface roughness and improve the surface flatness of the devices. Polishing liquids with a particle size in the range of 100 nanometers to 3 microns are widely used in fields such as optical lenses and glass surfaces. For example, in the rough polishing of blue glass, a polishing liquid with a particle size of about 1 micron is required for high polishing efficiency, and a polishing liquid with a particle size of about 300 nanometers is required for fine polishing to ensure surface flatness.
[0003] However, existing particle size classification methods, such as sieving method, sedimentation method, and dynamic light scattering method, have many deficiencies and often require complex equipment. For example, the sieving method has low precision when dealing with particle sizes of microns and below and cannot meet the high-precision classification requirements. For example, the ultrasonic-assisted sieving device designed by Tian Yu can sieve fine powder by introducing an ultrasonic device, but the device is relatively complex. Although the traditional sedimentation method is suitable for the classification of smaller particles, it lacks scientific and systematic data for operation guidance and often can only classify particles based on experience, which is difficult to use for some small enterprises. Although the dynamic light scattering method has high classification precision, it is limited by high equipment costs and strict requirements for sample characteristics and is difficult to achieve universal application. The limitations of these methods in terms of precision, efficiency, applicable range, and cost have become the key bottlenecks restricting the further development of polishing liquid particle size classification technology.
[0004] Therefore, there is an urgent need to establish a scientific, simple, and efficient particle size classification method to solve the problems that existing particle size classification methods have many deficiencies and often require complex equipment. Summary of the Invention
[0005] In order to solve the above technical problems, an embodiment of the present invention provides a method for classifying powder particles in a polishing liquid. The specific technical solution is as follows: In order to solve the above technical problems, the present invention is implemented as follows: A method for classifying powder particles in a polishing liquid is provided, which includes the following steps: preparing a polishing liquid with polishing powder having a certain particle size span and allowing it to stand; after the polishing liquid has stood for a period of time, taking out partial suspension solutions from different heights of the polishing liquid and diluting them; testing the absorbance of the taken-out and diluted suspension solutions, establishing the relationship between the absorbance of the suspension solutions at different heights and the corresponding height changes, and selecting appropriate height points according to the change relationship to perform multi-stage liquid separation on the polishing liquid to obtain polishing liquid products with different particle size distributions.
[0006] In one embodiment, the mass concentration range of the polishing powder in the prepared polishing liquid is 5% - 30%.
[0007] In one embodiment, the mass concentration range of the polishing powder in the prepared polishing liquid is preferably 10% - 20%.
[0008] In one embodiment, the standing time of the polishing liquid is a time period from more than half an hour to the time when the volume ratio of its suspension layer is less than 50%.
[0009] In one embodiment, the polishing liquid has an obvious suspension layer during the period when the polishing liquid stands, and the volume ratio of the suspension layer to the total volume of the polishing liquid is 90 - 100%.
[0010] In one embodiment, the volume ratio of the suspension layer to the total volume of the polishing liquid is preferably 98 - 100%.
[0011] In one embodiment, the median particle size of the selected polishing powder is 0.1 - 9 microns.
[0012] In one embodiment, the median particle size of the selected polishing powder is preferably 0.6 - 5 microns.
[0013] In the embodiments of the present invention, after the polishing liquid has stood for a period of time, partial suspension solutions are taken out from different heights of the polishing liquid and diluted, the relationship between the absorbance of the suspension solutions at different heights and the corresponding height changes is established, and appropriate height points are selected according to the change relationship to perform multi-stage liquid separation on the polishing liquid, so as to realize the classification of the powder particles in the polishing liquid and obtain polishing liquid products with different particle size distributions. The present invention classifies the polishing liquid by using the characteristics of the absorbance change of the suspension, and uses the scientific data of instrumental analysis as the evaluation criterion, so it has the advantage of scientificity, and the present invention has the advantages of high classification efficiency, simple operation, small particle loss, etc. It has a wide application range and can be used for the classification of both nano-scale particles and micro-scale particles. Description of the Drawings
[0014] The accompanying drawings described herein are used to provide a further understanding of the present invention and form a part of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 It is a flowchart of the steps of the method for classifying powder particles in the polishing liquid of the present invention; Figure 2 It is the original particle size diagram of Example 1 of the present invention; Figure 3 It is the curve of absorbance varying with height in Example 1 of the present invention; Figure 4 It is the particle size diagram at a height of 0 - 2 ml in Example 1 of the present invention; Figure 5 It is the particle size diagram at a height of 2 - 6 ml in Example 1 of the present invention; Figure 6 It is the particle size diagram at a height of 6 - 10 ml in Example 1 of the present invention; Figure 7 It is the curve of absorbance varying with height in Example 2 of the present invention Figure 8 It is the curve of absorbance varying with height in Example 3 of the present invention; Figure 9 It is the curve of absorbance varying with height in Example 4 of the present invention. Detailed implementation manners
[0015] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0016] Please refer to Figure 1 , which is a flowchart of the steps of the method for classifying powder particles in the polishing liquid of the present invention; As shown in the figure, the method for classifying powder particles in the polishing liquid of this embodiment includes the following steps S1 to S3. First, in step S1, a polishing liquid is prepared: polishing powder with a certain particle size span is taken to prepare the polishing liquid and left to stand. The particle size span refers to the value of (D90 - D10) / D50, where D90 is the maximum particle size of the polishing powder, D10 is the minimum particle size of the polishing powder, D50 is the median particle size of the polishing powder, and the larger the value of the particle size span, the more obvious the removal effect of large particles by this method. The median particle size D50 of the selected polishing powder is 0.1 - 9 microns, preferably 0.6 - 5 microns. The mass concentration range of the polishing powder in the prepared polishing liquid is 5% - 30%, preferably 10% - 20%.
[0017] Next, in S2, measurement solutions are taken from the polishing liquid at different heights: after the polishing liquid has been left standing for a period of time, partial suspension solutions are taken out from different heights of the polishing liquid and diluted. The polishing liquid has an obvious suspension layer during the period when it is left standing, and the volume ratio of the suspension layer to the total volume of the polishing liquid is 90 - 100%, preferably 98 - 100%. The standing time of the polishing liquid is the time period from more than half an hour to the time when the volume ratio of its suspension layer is less than 50%. Then the polishing liquid is divided into certain positions according to height, a certain volume of solution, preferably 1 - 5 ml, is selected at each height position, and the solutions at different height positions selected are diluted to make their concentrations meet the test range of the instrument for detecting absorbance.
[0018] Finally, in S3, the suspension liquid is subjected to layering treatment: the absorbance of the taken-out and diluted suspension solution is measured, the relationship between the absorbance of the suspension solution at different heights and the corresponding height change is established, and appropriate height positions are selected according to the change relationship to perform multi-stage liquid separation on the polishing liquid to obtain polishing liquid products with different particle size distributions. The diluted suspension solutions at each height position in test step S2 are measured, the change relationship curve between the absorbance and the selected different height positions is established, and then the height positions with an obvious change rate of the change relationship curve are selected for liquid separation to obtain polishing liquid products with different particle size distributions.
[0019] In the method for classifying powder particles in the polishing liquid of this embodiment, after the polishing liquid is prepared and left standing for a period of time, partial suspension solutions are taken out from different heights of the polishing liquid and diluted, the relationship between the absorbance of the suspension solution at different heights and the corresponding height change is established, and appropriate height positions are selected according to the change relationship to perform multi-stage liquid separation on the polishing liquid, so as to realize the classification of the powder particles in the polishing liquid and obtain polishing liquid products with different particle size distributions. This embodiment classifies the polishing liquid by using the characteristics of the change in the absorbance of the suspension liquid, and uses the scientific data of instrumental analysis as the judgment standard, so it has the advantage of being scientific. Moreover, this embodiment has the advantages of high classification efficiency, simple operation, and small particle loss, and has a wide application range, and can be used for the classification of both nano-scale particles and micro-scale particles.
[0020] The beneficial effects of the method for classifying powder particles in the polishing liquid of the present invention will be described below with specific examples.
[0021] Example 1 1. Cerium oxide powder (D50 = 0.645 microns) is prepared into a polishing liquid with a mass concentration of 20%, a total of 10 ml, and its particle size distribution is as Figure 2 shown.
[0022] 2. After the above polishing liquid is configured, there is an obvious suspension layer after 1 hour, and the volume ratio of the suspension layer is greater than 98% of the total volume, without an obvious clarification layer and precipitation layer. 0.3 ml of the solution is selected and diluted at different height positions (10 ml, 8 ml, 6 ml, 4 ml, 2 ml, 0 ml positions of the measuring cylinder) respectively; 3. Measure the absorbance of the above-mentioned taken and diluted solutions respectively, establish the change relationship between the absorbance of the solutions at each height and the selected height positions. The specific values are shown in Table 1, and the change relationship is as Figure 3 shown.
[0023] Table 1: The relationship between the absorbance and the change rate of Examples 1-4 with height According to Table 1 and Figure 3 it can be seen that as the height position decreases, the absorbance generally shows an increasing trend. Among them, the changes are obvious at 0-2 ml, 2-6 ml, and 6-10 ml. The change rates at the height positions of 2 ml and 6 ml (the difference between the absorbance of the latter position and the absorbance of the previous position divided by the absorbance value of the previous position) are 1.74% and 5.78% respectively, while the changes at other positions are not obvious, all not exceeding 1%. Therefore, the polishing liquid is divided into three parts according to these two positions, namely 0-2 ml component, 2-6 ml component, and 6-10 ml component. After liquid separation, measure the particle sizes of the three solution components. The data are shown in Table 2, and its height particle size diagram is as Figures 4 - 6 shown.
[0024] Table 2: The particle sizes of each component after liquid separation in Example 1 Liquid separation component of polishing liquid 0-2ml 2-6ml 6-10ml D50 / μm 0.924 0.557 0.461 According to Table 2, three polishing liquids with different particle sizes are obtained after liquid separation of Example 1 according to this method. The D50 values are 0.924 microns, 0.557 microns, and 0.461 microns respectively. These polishing liquids can be applied to different products. This proves that this method has the advantages of being scientific, efficient, and simple, and has great application prospects.
[0025] Example 2 The difference between this Example 2 and the above Example 1 is that in this Example 2, cerium oxide powder (D50 = 0.645 microns) is formulated into a polishing liquid with a mass concentration of 5%. Other conditions are the same as those in Example 1. Therefore, the steps of this Comparative Example 1 are referred to as shown in the above Example 1 and will not be repeated here. The specific values are shown in Table 1, and the change relationship is as Figure 4 shown.
[0026] According to Table 1 and Figure 7It can be seen that as the height decreases, the absorbance generally shows an increasing trend, with obvious changes at 0-2 ml, 2-8 ml, and 8-10 ml. The change rates at the height positions of 2 ml and 8 ml are 10.51% and 17.59% respectively, while the changes at other positions are not obvious, all not exceeding 4%. Therefore, the polishing liquid is divided into three parts according to these two positions, namely 0-2 ml component, 2-8 ml component, and 8-10 ml component. After liquid separation, the particle sizes of these three solutions are measured, and the data are shown in Table 3.
[0027] Table 3: Particle Sizes of Each Component after Liquid Separation in Example 2 Liquid separation component of polishing liquid 0-2ml 2-8ml 8-10ml D50 / μm 0.770 0.634 0.538 As can be seen from Table 3, three polishing liquids with different particle sizes are obtained after liquid separation in Example 2 according to this method, and the D50 values are 0.77 μm, 0.634 μm, and 0.538 μm respectively. These polishing liquids can be applied to different products. This proves that this method has the advantages of being scientific, efficient, and simple, and has great application prospects.
[0028] Example 3 The difference between this Example 3 and the above Example 1 is that in this Example 3, cerium oxide powder (D50 = 0.645 μm) is formulated into a polishing liquid with a mass concentration of 30%, and other conditions are the same as those in Example 1. Therefore, the steps of this Comparative Example 1 can be referred to those shown in the above Example 1 and will not be elaborated here. The specific values are shown in Table 1, and the change relationship is as Figure 8 shown.
[0029] According to Table 1 and Figure 7 it can be seen that as the height decreases, the absorbance generally shows an increasing trend, with obvious changes at 0-2 ml, 2-4 ml, and 4-10 ml. The change rates at the height positions of 2 ml and 4 ml are 21.87% and 1.46% respectively, while the changes at other positions are not obvious. Therefore, the polishing liquid is divided into three parts according to these two positions, namely 0-2 ml component, 2-4 ml component, and 4-10 ml component. After liquid separation, the particle sizes of these three solutions are measured, and the data are shown in Table 4.
[0030] Table 4: Particle Sizes of Each Component after Liquid Separation in Example 3 Liquid separation component of polishing liquid 0-2ml 2-4ml 4-10ml D50 / μm 0.834 0.697 0.342 As can be seen from Table 4, three polishing liquids with different particle sizes are obtained after liquid separation in Example 3 according to this method, and the D50 values are 0.834 μm, 0.697 μm, and 0.342 μm respectively. These polishing liquids can be applied to different products. This proves that this method has the advantages of being scientific, efficient, and simple, and has great application prospects.
[0031] Example 4 The difference between Example 3 and the above Example 1 is that in Example 3, cerium oxide powder (D50 = 9.289 microns) is formulated into a polishing liquid with a mass concentration of 20%. Other conditions are the same as those in Example 1. Therefore, for the steps of Comparative Example 1, please refer to those shown in Example 1 above and will not be elaborated here. The specific values are shown in Table 1, and the variation relationship is as Figure 9 shown.
[0032] According to Table 1 and Figure 9 it can be seen that as the height decreases, the absorbance generally shows an increasing trend, with obvious changes at 0 - 2 ml, 2 - 10 ml, and 8 - 10 ml. The change rates at the height positions of 2 ml and 8 ml are 91.15% and 29.76% respectively, while the changes at other positions are not obvious. Therefore, the polishing liquid is divided into three parts according to these two positions, namely the 0 - 2 ml component, the 2 - 8 ml component, and the 8 - 10 ml component. After liquid separation, the particle sizes of these three solutions are measured, and the data are shown in Table 5.
[0033] Table 5: Particle sizes of each component after liquid separation in Example 4 Liquid separation component of polishing liquid 0-2ml 2-8ml 8-10ml D50 / μm 8.762 1.350 0.810 According to Table 5, three polishing liquids with different particle sizes are obtained after liquid separation of Example 4 according to this method, and the D50 values are 8.762 microns, 1.350 microns, and 0.810 microns respectively. These polishing liquids can be applied to different products. This proves that this method has the advantages of being scientific, efficient, and simple, and has great application prospects.
[0034] In summary, the present invention provides a method for classifying powder particles in a polishing liquid. After the polishing liquid is allowed to stand for a period of time, partial suspension solutions are taken out at different heights of the polishing liquid and diluted. The change relationship between the absorbance of the suspension solutions at different heights and the corresponding heights is established, and appropriate height positions are selected according to the change relationship to perform multi - stage liquid separation on the polishing liquid, thereby realizing the classification of powder particles in the polishing liquid and obtaining polishing liquid products with different particle size distributions. The present invention classifies the polishing liquid by utilizing the characteristics of the change in the absorbance of the suspension, and uses the scientific data of instrumental analysis as the evaluation criterion. Therefore, it has the advantage of being scientific, and the present invention also has the advantages of high classification efficiency, simple operation, and small particle loss. It has a wide range of applications and can be used for the classification of both nano - scale particles and micron - scale particles.
[0035] It should be noted that in this text, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the existence of additional identical elements in the process, method, article or device comprising such element.
[0036] The embodiments of the present invention have been described above in conjunction with the accompanying drawings. However, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the spirit and scope of the present invention as protected by the claims, and all of them fall within the protection scope of the present invention.
Claims
1. A method for classifying powder particles in a polishing liquid, characterized in that: The following steps are involved: Take polishing powder with a certain particle size span to prepare polishing liquid and let it stand; After the polishing liquid is left to stand for a period of time, taking out parts of the suspension solution at different heights in the polishing liquid respectively and diluting them; The absorbance of the suspended solution after being taken out and diluted is tested, and the relationship between the absorbance of the suspended solution at different heights and the corresponding height is established. According to the relationship, a suitable height point is selected to perform multi-stage separation on the polishing liquid to obtain polishing liquid products with different particle size distributions.
2. The method for classifying powder particles in a polishing liquid according to claim 1, characterized in that: The mass concentration range of the polishing powder in the configured polishing liquid is 5% to 30%.
3. The method for classifying powder particles in a polishing liquid according to claim 1 or 2, characterized in that: The mass concentration range of the polishing powder in the configured polishing liquid is preferably 10% to 20%.
4. The method for classifying powder particles in a polishing liquid according to claim 1, characterized in that: The standing time of the polishing liquid is a time period from more than half an hour to the time when the volume ratio of the suspension layer thereof is less than 50%.
5. The method for classifying powder particles in a polishing liquid according to claim 1, characterized in that: The polishing liquid has an obvious suspension layer after being left to stand for a period of time, and the suspension layer accounts for 90-100% of the total volume of the polishing liquid.
6. The method for classifying powder particles in a polishing liquid according to claim 5, characterized in that: The suspension layer preferably accounts for 98-100% of the total volume of the polishing liquid.
7. The method for classifying powder particles in a polishing liquid according to claim 1, characterized in that: The median particle size of the selected polishing powder is 0.1 to 9 microns.
8. The method for classifying powder particles in a polishing liquid according to claim 7, characterized in that: The median particle size of the selected polishing powder is preferably 0.6 to 5 microns.