A wear-resistant composite polishing powder and its preparation method

Abstract

The present invention discloses a wear-resistant composite polishing powder and a preparation method thereof, relating to the technical field of polishing powder preparation; the wear-resistant composite polishing powder consists of a modified hexagonal boron nitride@cerium oxide composite core and a wear-resistant efficiency-enhancing protective layer; the modified hexagonal boron nitride@cerium oxide composite core consists of a modified hexagonal boron nitride carrier, cerium oxide, polyvinylpyrrolidone and samarium oxide; by completely coating the main phase cerium oxide on the modified hexagonal boron nitride carrier and forming doping with samarium oxide on the modified hexagonal boron nitride carrier, a modified hexagonal boron nitride@cerium oxide composite core is obtained, and then copper oxide is loaded on the surface of the core to form a wear-resistant efficiency-enhancing protective layer, effectively enhancing the wear resistance of the composite polishing powder, reducing the loss during use, being beneficial to extending the service life, also improving the dispersibility of the composite polishing powder, further enhancing the durability, and simultaneously achieving excellent polishing effects.

Description

Technical Field

[0001] The present invention belongs to the technical field of polishing powder preparation, and specifically refers to a wear-resistant composite polishing powder and a preparation method thereof. Background Art

[0002] As a method capable of achieving local and global planarization of silicon wafers, chemical mechanical polishing technology is widely used in the planarization treatment of the surface of Si wafers. Currently, the most commonly used abrasive polishing materials in the world are cerium-based oxides mainly composed of cerium oxide or lanthanum cerium oxide. These cerium-based oxide polishing powders mostly use water as a dispersant and are used after being mixed into a slurry; cerium-based oxide polishing powders have unique physical and chemical properties, excellent polishing performance, and low pollution to Si wafers, and are widely used in many fields such as mobile phone covers, optical glass, liquid crystal displays, crystal ornaments, integrated circuits, and precision optical components; however, with the development of technology and the more stringent quality requirements for silicon wafers, simple cerium oxide polishing powder has been difficult to meet the process requirements. Therefore, it is urgent to improve cerium oxide and cerium-based oxide polishing powders to meet the increasingly high production standards.

[0003] Currently, the existing technologies mainly have the following problems:

[0004] The wear resistance of cerium-based oxide polishing powder is general, and it is easy to agglomerate and has poor dispersibility during use, which has an adverse impact on the service life and polishing effect of cerium-based oxide polishing powder. Summary of the Invention

[0005] In view of the above situation, to overcome the defects of the existing technology, the present invention proposes a wear-resistant composite polishing powder, which includes the following components in parts by weight: 80 - 100 parts of modified hexagonal boron nitride @ cerium oxide composite core, and 10 - 25 parts of wear-resistant efficiency enhancing protective layer.

[0006] The modified hexagonal boron nitride @ cerium oxide composite core includes the following components in parts by weight: 10 - 20 parts of modified hexagonal boron nitride carrier, 30 - 50 parts of cerium oxide, 10 - 20 parts of polyvinylpyrrolidone, and 8 - 12 parts of samarium oxide.

[0007] The modified hexagonal boron nitride carrier is obtained by using sodium hydroxide-assisted physical ball milling to exfoliate hexagonal boron nitride into nanosheets and preliminarily hydroxylate it, and then further hydroxylate it by hydrothermal method.

[0008] The wear-resistant efficiency enhancing protective layer is a shell material formed by using copper nitrate as a surface modification component and obtaining copper oxide loaded on the core.

[0009] The preparation method of the modified hexagonal boron nitride carrier specifically includes the following steps:

[0010] (1) Add 20 mL of 5 mol / L sodium hydroxide solution, zirconia grinding balls and hexagonal boron nitride powder with a mass ratio of 20:1 into the ball mill tank. Control the rotation speed at 300 - 400 rpm and the grinding time at 12 - 24 h. After sieving, the obtained hexagonal boron nitride slurry is centrifuged at a speed of 1000 - 2000 rpm for 5 - 10 min. Take the upper suspension and centrifuge it again at a speed of 9000 - 10000 rpm for 5 - 10 min. The precipitate is freeze-dried. Through sodium hydroxide-assisted physical ball milling, hexagonal boron nitride is exfoliated into nanosheets and preliminarily hydroxylated and modified, reducing the adverse phenomena caused by the agglomeration of hexagonal boron nitride and improving the wettability, thus obtaining hexagonal boron nitride nanosheet powder.

[0011] (2) Add 1.0 - 2.0 g of the hexagonal boron nitride nanosheet powder obtained in step (1) into 150 mL of 5 mol / L sodium hydroxide solution, mix evenly with a magnetic stirrer, and then perform ultrasonic dispersion treatment. Pour the mixed solution into a three-necked flask and continuously reflux it in an oil bath at 100 - 120 °C for 24 h. Cool and filter the obtained solution, wash it with 1 mol / L hydrochloric acid solution and deionized water respectively until the solution is neutral to fully remove the residual sodium hydroxide, and then freeze-dry it. Further hydroxylation modification of the hexagonal boron nitride nanosheet powder is carried out by the sodium hydroxide hydrothermal method to improve its wettability and dispersibility in aqueous solution, thus obtaining a modified hexagonal boron nitride carrier.

[0012] Preferably, in step (2), during the ultrasonic dispersion process, the ultrasonic power is 600 - 800 W and the ultrasonic time is 20 - 30 min. The ultrasonic dispersion treatment is beneficial for the better contact modification of the hexagonal boron nitride nanosheet powder with the sodium hydroxide solution.

[0013] The present invention also provides a preparation method of a wear-resistant composite polishing powder, which specifically includes the following steps:

[0014] S1. Add 1.0 - 2.0 g of modified hexagonal boron nitride support to 100 mL of deionized water, add 0.8 - 1.2 g of samarium nitrate hexahydrate, stir to mix evenly, and set aside. Weigh 3.0 - 5.0 g of cerium nitrate hexahydrate and 1.0 - 2.0 g of polyvinylpyrrolidone powder and dissolve them in a mixed solution of 150 mL of ethylene glycol and 10 mL of deionized water, stir for 1 h, then add the mixed solution of modified hexagonal boron nitride support and samarium nitrate hexahydrate, stir evenly, transfer the solution to a 400 mL stainless steel reaction kettle with a polytetrafluoroethylene inner lining, place it in a microwave hydrothermal reaction tank. After the reaction is completed, naturally cool to room temperature, centrifuge the product, wash it 3 - 5 times with deionized water and anhydrous ethanol solution in turn, then put it into an oven and dry it at 50 - 60 °C for 12 h, and calcine it in a muffle furnace at 400 - 500 °C in an air atmosphere for 2 - 3 h. Through hydrothermal reaction and calcination treatment, a small amount of samarium oxide is loaded on the modified hexagonal boron nitride support. As the most core component, the two work together to improve the dispersibility and suspension of cerium oxide polishing powder in the way of doping and support, improve the polishing uniformity and polishing efficiency. The main phase substance cerium oxide completely coats the samarium oxide and the modified hexagonal boron nitride support to form a composite structure, enabling cerium oxide to obtain a favorable internal support, effectively enhancing the hardness and chemical stability of the polishing powder, thus maintaining good wear resistance and polishing performance during the polishing process, and obtaining a modified hexagonal boron nitride@cerium oxide composite core;

[0015] S2. Dissolve the modified hexagonal boron nitride@cerium oxide composite core described in step S1 in 100 - 200 mL of deionized water, ultrasonically disperse it for 10 - 20 min, add copper nitrate powder, continuously stir for 1 - 2 h, heat up to 90 °C and stir the solution to dryness, put the product into a muffle furnace and calcine it at 400 - 500 °C in an air atmosphere for 2 - 3 h. The obtained copper oxide is loaded on the surface of the modified hexagonal boron nitride@cerium oxide composite core to form a wear-resistant and efficiency-enhancing protective layer, further reducing the loss and breakage of cerium oxide during the polishing process, improving the wear resistance. This sandwich-like structure also reduces the agglomeration phenomenon of cerium oxide polishing powder. In addition, it significantly increases the concentration of oxygen vacancies in the abrasive, promotes the combination of Ce - O - Si bonds, enhances the reaction activity, thereby improving the polishing efficiency and polishing effect, and obtaining a wear-resistant composite polishing powder;

[0016] Preferably, in step S1, during the microwave hydrothermal reaction process, control the temperature to be kept at 70 - 80 °C for 0.5 - 1 h, and then at 150 - 160 °C for 6 - 7 h. Under microwave hydrothermal conditions, cerium oxide continuously grows on the modified hexagonal boron nitride support, so that the modified hexagonal boron nitride support is coated inside the cerium oxide;

[0017] Preferably, in step S2, the addition amount of copper nitrate is 0.2 - 0.5 g. The interaction between copper ions and cerium ions forms a redox pair, which reduces some tetravalent cerium ions to trivalent cerium ions, improving the polishing performance of cerium oxide.

[0018] The beneficial effects achieved by the present invention are as follows:

[0019] In the present invention, the main phase cerium oxide completely coats the modified hexagonal boron nitride carrier and forms a doping with samarium oxide on the modified hexagonal boron nitride carrier, obtaining a modified hexagonal boron nitride@cerium oxide composite core. Then, copper oxide is loaded on the surface of the core to form an abrasion-resistant and efficiency-enhancing protective layer, effectively enhancing the abrasion resistance of the composite polishing powder, reducing the loss during use, being beneficial to extending the service life, also improving the dispersibility of the composite polishing powder, further enhancing the durability, and simultaneously achieving an excellent polishing effect; in the modified hexagonal boron nitride@cerium oxide composite core, cerium oxide grows on the modified hexagonal boron nitride carrier, completely coating the modified hexagonal boron nitride carrier and doping the samarium oxide loaded on the modified hexagonal boron nitride carrier, improving the dispersibility of cerium oxide in the form of doping and a carrier, reducing the agglomeration phenomenon in water, increasing the polishing uniformity and polishing efficiency. At the same time, the addition of the modified hexagonal boron nitride carrier and samarium oxide makes the cerium oxide polishing powder denser, reduces defects, increases the hardness of the cerium oxide polishing powder, and makes it more abrasion-resistant; the abrasion-resistant and efficiency-enhancing protective layer is obtained by loading copper oxide obtained by calcination on the surface of the modified hexagonal boron nitride@cerium oxide composite core, forming a sandwich-like inclusion structure, further reducing the loss and breakage of cerium oxide during the polishing process, improving the abrasion resistance. At the same time, it also promotes the reduction of some tetravalent cerium ions to trivalent cerium ions, increasing the concentration of oxygen vacancies in the abrasive, promoting the combination of Ce - O - Si bonds, thereby improving the polishing efficiency and polishing effect of the cerium oxide polishing powder; the present invention uses the modified hexagonal boron nitride@cerium oxide composite core and the abrasion-resistant and efficiency-enhancing protective layer to prepare an abrasion-resistant composite polishing powder, which has excellent dispersibility and abrasion resistance, is beneficial to achieving a good polishing effect, improving the polishing efficiency, and extending the service life of the polishing powder. Description of the Drawings

[0020] Figure 1 It is a transmission electron microscope image of the modified hexagonal boron nitride carrier prepared in Example 1 of the present invention;

[0021] Figure 2 It is a scanning electron microscope image of the abrasion-resistant composite polishing powder prepared in Example 1 of the present invention;

[0022] Figure 3 It is a graph of the particle size reduction rate results of Examples 1 - 4 and Comparative Examples 1 - 3 of the present invention;

[0023] Figure 4This is the polishing performance result diagram for Examples 1-4 and Comparative Examples 1-3 of the present invention. Detailed implementation manners

[0024] 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 only a part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0025] Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to the described content can be applied to the present invention. The preferred implementation methods and materials described herein are only for illustrative purposes and do not limit the content of this application.

[0026] The experimental methods in the following embodiments are all conventional methods unless otherwise specified; the test materials used in the following embodiments are all obtained from commercial channels unless otherwise specified.

[0027] The sources of the reagents used in the examples are as follows:

[0028] Hexagonal boron nitride CAS No: 10043-11-5, brand Innochem, product number A67186;

[0029] Hydrochloric acid CAS No: 7647-01-0, brand Innochem, product number A04558;

[0030] Samarium nitrate hexahydrate CAS No: 13759-83-6, brand Innochem, product number A28163;

[0031] Cerium nitrate hexahydrate CAS No: 10294-41-4, brand Innochem, product number A22708;

[0032] Polyvinylpyrrolidone CAS No: 9003-39-8, brand Innochem, product number A38579;

[0033] Ethylene glycol CAS No: 107-21-1, brand Innochem, product number A82640;

[0034] Copper nitrate CAS No: 3251-23-8, brand Macklin, product number C860751-100g;

[0035] Sodium hydroxide CAS No: 1310-73-2, brand Innochem, product number A36865;

[0036] Absolute ethanol, CAS No: 64-17-5, brand Innochem, product number G00004.

[0037] Example 1

[0038] This example presents a wear-resistant composite polishing powder, which includes the following components in parts by weight: 100 parts of modified hexagonal boron nitride@cerium oxide composite core, and 25 parts of wear-resistant efficiency-enhancing protective layer.

[0039] The modified hexagonal boron nitride@cerium oxide composite core includes the following components in parts by weight: 20 parts of modified hexagonal boron nitride carrier, 50 parts of cerium oxide, 20 parts of polyvinylpyrrolidone, and 12 parts of samarium oxide.

[0040] The modified hexagonal boron nitride carrier is prepared by sodium hydroxide-assisted physical ball milling to exfoliate hexagonal boron nitride into nanosheets while preliminarily performing hydroxylation modification, and then further hydroxylation modification is carried out by hydrothermal method.

[0041] The wear-resistant efficiency-enhancing protective layer is a shell material formed by using copper nitrate as a surface modification component and obtaining copper oxide loaded on the core.

[0042] The preparation method of the modified hexagonal boron nitride carrier specifically includes the following steps:

[0043] (1) Add 20 mL of 5 mol / L sodium hydroxide solution, zirconia grinding balls and hexagonal boron nitride powder with a mass ratio of 20:1 into the ball mill tank, control the rotation speed at 400 rpm, the grinding time at 24 h, sieve, and perform centrifugation on the obtained hexagonal boron nitride slurry at a centrifugation speed of 2000 rpm and a centrifugation time of 10 min. Take the upper suspension and perform centrifugation again at a centrifugation speed of 10000 rpm and a centrifugation time of 10 min. Freeze-dry the precipitate. Through sodium hydroxide-assisted physical ball milling, hexagonal boron nitride is exfoliated into nanosheets while preliminarily performing hydroxylation modification, reducing the adverse phenomena caused by the aggregation of hexagonal boron nitride and improving the wettability, obtaining hexagonal boron nitride nanosheet powder;

[0044] (2) Add 2.0 g of the hexagonal boron nitride nanosheet powder described in step (1) to 150 mL of 5 mol / L sodium hydroxide solution, mix well with a magnetic stirrer, and then perform ultrasonic dispersion treatment. During the ultrasonic dispersion process, the ultrasonic power is 800 W and the ultrasonic time is 30 min. The ultrasonic dispersion treatment is beneficial for the better contact modification of the hexagonal boron nitride nanosheet powder with the sodium hydroxide solution. Pour the mixed solution into a three-necked flask and continuously reflux in an oil bath at 120 °C for 24 h. Cool and filter the obtained solution, and wash it with 1 mol / L hydrochloric acid solution and deionized water until the solution is neutral to fully remove the residual sodium hydroxide. Then freeze-dry it. Further hydroxylation modification of the hexagonal boron nitride nanosheet powder is carried out by the sodium hydroxide hydrothermal method to improve its wettability and dispersibility in aqueous solution, and a modified hexagonal boron nitride support is obtained.

[0045] This example provides a preparation method of a wear-resistant composite polishing powder, which specifically includes the following steps:

[0046] S1. Add 2.0 g of the modified hexagonal boron nitride support to 100 mL of deionized water, add 1.2 g of samarium nitrate hexahydrate, stir to mix evenly, and set aside. Weigh 5.0 g of cerium nitrate hexahydrate and 2.0 g of polyvinylpyrrolidone powder and dissolve them in a mixed solution of 150 mL of ethylene glycol and 10 mL of deionized water, stir for 1 h, then add the mixed solution of the modified hexagonal boron nitride support and samarium nitrate hexahydrate, stir evenly, transfer the solution to a 400 mL stainless steel reaction kettle with a polytetrafluoroethylene liner, place it in a microwave hydrothermal reaction tank. During the microwave hydrothermal reaction, control the temperature to keep warm at 80 °C for 1 h, and then keep warm at 160 °C for 7 h. Under the microwave hydrothermal conditions, cerium oxide continuously grows on the modified hexagonal boron nitride support, so that the modified hexagonal boron nitride support is coated inside the cerium oxide. After the reaction is completed, naturally cool to room temperature, centrifuge the product, wash it 5 times with deionized water and anhydrous ethanol solution in turn, then put it into an oven and dry it at 60 °C for 12 h, and calcine it in a muffle furnace at 500 °C in an air atmosphere for 3 h. Through hydrothermal reaction and calcination treatment, a small amount of samarium oxide is loaded on the modified hexagonal boron nitride support, which is the most core component. The two work together to improve the dispersibility and suspension of the cerium oxide polishing powder in the form of doping and support, improve the polishing uniformity and polishing efficiency. The main phase substance cerium oxide completely coats the samarium oxide and the modified hexagonal boron nitride support to form a composite structure, so that the cerium oxide obtains a favorable internal support, effectively enhancing the hardness and chemical stability of the polishing powder, and thus maintaining good wear resistance and polishing performance during the polishing process, and obtaining a modified hexagonal boron nitride@cerium oxide composite core;

[0047] S2. Dissolve the modified hexagonal boron nitride@cerium oxide composite core described in step S1 in 200 mL of deionized water, ultrasonically disperse for 20 min, add copper nitrate powder, and the addition amount of copper nitrate is 0.5 g. Due to the interaction between copper ions and cerium ions, by forming a redox pair, part of the tetravalent cerium ions are reduced to trivalent cerium ions, improving the polishing performance of cerium oxide. Continuously stir for 2 h, heat the solution to 90 °C and stir to evaporate to dryness. Put the product into a muffle furnace and calcine in an air atmosphere at 500 °C for 3 h. The obtained copper oxide is loaded on the surface of the modified hexagonal boron nitride@cerium oxide composite core to form a wear-resistant and efficiency-enhancing protective layer, further reducing the loss and fragmentation of cerium oxide during the polishing process, improving the wear resistance. This sandwich-like structure also reduces the agglomeration phenomenon of cerium oxide polishing powder. In addition, it significantly increases the concentration of oxygen vacancies in the abrasive, promotes the bonding of Ce-O-Si bonds, enhances the reaction activity, thereby improving the polishing efficiency and polishing effect, and obtaining a wear-resistant composite polishing powder.

[0048] In this example, the prepared modified hexagonal boron nitride carrier was subjected to transmission electron microscopy, and the wear-resistant composite polishing powder was subjected to scanning electron microscopy to observe its microscopic morphology. Figure 1 Figure 5 shows a TEM image of the modified hexagonal boron nitride carrier prepared in Example 1 magnified 100,000 times. Figure 2 Figure 7 shows an SEM image of the wear-resistant composite polishing powder prepared in Example 1 magnified 10,000 times. As Figure 1 , the modified hexagonal boron nitride carrier prepared in this example is in the shape of a thin sheet, as Figure 2 , the wear-resistant composite polishing powder prepared in this example is an inclusion compound.

[0049] Example 2

[0050] This example presents a wear-resistant composite polishing powder, which includes the following components in parts by weight: 80 parts of modified hexagonal boron nitride@cerium oxide composite core and 10 parts of wear-resistant and efficiency-enhancing protective layer.

[0051] The modified hexagonal boron nitride@cerium oxide composite core includes the following components in parts by weight: 10 parts of modified hexagonal boron nitride carrier, 30 parts of cerium oxide, 10 parts of polyvinylpyrrolidone, and 8 parts of samarium oxide.

[0052] The modified hexagonal boron nitride carrier is prepared by sodium hydroxide-assisted physical ball milling to exfoliate hexagonal boron nitride into nanosheets and preliminarily carry out hydroxylation modification, and then further hydroxylation modification is carried out by hydrothermal method.

[0053] The wear-resistant and efficiency-enhancing protective layer is a shell material formed by using copper nitrate as a surface modification component and loading the obtained copper oxide on the core.

[0054] The preparation method of the modified hexagonal boron nitride carrier specifically includes the following steps:

[0055] (1) Add 20 mL of 5 mol / L sodium hydroxide solution, zirconia grinding balls and hexagonal boron nitride powder with a mass ratio of 20:1 into the ball mill tank. Control the rotation speed at 300 rpm and the grinding time at 12 h. After sieving, the obtained hexagonal boron nitride slurry is centrifuged at a speed of 1000 rpm for 5 min. Take the upper suspension and centrifuge it again at a speed of 9000 rpm for 5 min. The precipitate is freeze-dried. Through sodium hydroxide-assisted physical ball milling, hexagonal boron nitride is exfoliated into nanosheets and preliminarily hydroxylated, reducing the adverse phenomena caused by the agglomeration of hexagonal boron nitride and improving the wettability, thus obtaining hexagonal boron nitride nanosheet powder.

[0056] (2) Add 1.0 g of the hexagonal boron nitride nanosheet powder obtained in step (1) into 150 mL of 5 mol / L sodium hydroxide solution, mix it evenly with a magnetic stirrer, and then perform ultrasonic dispersion treatment. During the ultrasonic dispersion process, the ultrasonic power is 600 W and the ultrasonic time is 20 min. The ultrasonic dispersion treatment is beneficial for the hexagonal boron nitride nanosheet powder to better contact and modify with the sodium hydroxide solution. Pour the mixed solution into a three-necked flask and continuously reflux it in an oil bath at 100 °C for 24 h. Cool and filter the obtained solution, wash it with 1 mol / L hydrochloric acid solution and deionized water respectively until the solution is neutral to fully remove the residual sodium hydroxide, and then freeze-dry it. Further hydroxylation modification of the hexagonal boron nitride nanosheet powder is carried out by the sodium hydroxide hydrothermal method, improving its wettability and dispersibility in aqueous solution, and obtaining a modified hexagonal boron nitride carrier.

[0057] This example provides a preparation method of wear-resistant composite polishing powder, which specifically includes the following steps:

[0058] S1. Add 1.0 g of modified hexagonal boron nitride support into 100 mL of deionized water, then add 0.8 g of samarium nitrate hexahydrate, stir to make them mix evenly for later use. Weigh 3.0 g of cerium nitrate hexahydrate and 1.0 g of polyvinylpyrrolidone powder and dissolve them in a mixed solution of 150 mL of ethylene glycol and 10 mL of deionized water, stir for 1 h, then add the mixed solution of modified hexagonal boron nitride support and samarium nitrate hexahydrate, stir evenly, transfer the solution to a 400 mL stainless steel reaction kettle with a polytetrafluoroethylene inner lining, put it into a microwave hydrothermal reaction tank. During the microwave hydrothermal reaction process, control the temperature to keep warm at 70 °C for 0.5 h, and then keep warm at 150 °C for 6 h. Under the microwave hydrothermal condition, cerium oxide continuously grows on the modified hexagonal boron nitride support, so that the modified hexagonal boron nitride support is coated inside the cerium oxide. After the reaction ends, naturally cool it to room temperature, centrifuge the product, wash it 3 times with deionized water and anhydrous ethanol solution in turn, then put it into an oven and dry it at 50 °C for 12 h, and calcine it in a muffle furnace at 400 °C in an air atmosphere for 2 h. Through hydrothermal reaction and calcination treatment, a small amount of samarium oxide is loaded on the modified hexagonal boron nitride support, which is the most core component. The two work together to improve the dispersibility and suspension of cerium oxide polishing powder in the way of doping and support, improve the polishing uniformity and polishing efficiency. The main phase substance cerium oxide completely coats samarium oxide and the modified hexagonal boron nitride support to form a composite structure, enabling cerium oxide to obtain a favorable internal support, effectively enhancing the hardness and chemical stability of the polishing powder, so as to maintain good wear resistance and polishing performance during the polishing process, and obtain the modified hexagonal boron nitride@cerium oxide composite core;

[0059] S2. Dissolve the modified hexagonal boron nitride@cerium oxide composite core described in step S1 in 100 mL of deionized water, ultrasonically disperse it for 10 min, add copper nitrate powder, and the addition amount of copper nitrate is 0.2 g. Due to the interaction between copper ions and cerium ions, by forming a redox pair, part of the tetravalent cerium ions are reduced to trivalent cerium ions, improving the polishing performance of cerium oxide. Continuously stir for 1 h, raise the temperature to 90 °C and stir the solution to dryness. Put the product into a muffle furnace and calcine it at 400 °C in an air atmosphere for 2 h. The obtained copper oxide is loaded on the surface of the modified hexagonal boron nitride@cerium oxide composite core to form a wear-resistant and efficiency-enhancing protective layer, further reducing the loss and breakage of cerium oxide during the polishing process, improving the wear resistance. This sandwich-like structure also reduces the agglomeration phenomenon of cerium oxide polishing powder. In addition, it significantly increases the concentration of oxygen vacancies in the abrasive, promotes the combination of Ce-O-Si bonds, enhances the reaction activity, thereby improving the polishing efficiency and polishing effect, and obtaining a wear-resistant composite polishing powder.

[0060] Example 3

[0061] This embodiment provides a wear-resistant composite polishing powder, which comprises the following components in parts by weight: 90 parts of modified hexagonal boron nitride@cerium oxide composite core and 17.5 parts of wear-resistant efficiency-enhancing protective layer.

[0062] The modified hexagonal boron nitride@cerium oxide composite core comprises the following components in parts by weight: 15 parts of modified hexagonal boron nitride carrier, 40 parts of cerium oxide, 15 parts of polyvinylpyrrolidone, and 10 parts of samarium oxide.

[0063] The modified hexagonal boron nitride carrier is obtained by subjecting hexagonal boron nitride to sodium hydroxide-assisted physical ball milling to exfoliate it into nanosheets while preliminarily performing hydroxylation modification, and then further performing hydroxylation modification using the hydrothermal method.

[0064] The wear-resistant efficiency-enhancing protective layer is a shell material formed by using copper nitrate as a surface modification component and obtaining copper oxide loaded on the core.

[0065] The preparation method of the modified hexagonal boron nitride carrier specifically includes the following steps:

[0066] (1) Add 20 mL of 5 mol / L sodium hydroxide solution, zirconia grinding balls with a mass ratio of 20:1, and hexagonal boron nitride powder into the ball mill tank. Control the rotation speed at 350 rpm, the grinding time at 18 h, and sieve. The obtained hexagonal boron nitride slurry is centrifuged at a speed of 1500 rpm for 7.5 min. Take the upper suspension and centrifuge it again at a speed of 9500 rpm for 7.5 min. The precipitate is freeze-dried. Through sodium hydroxide-assisted physical ball milling, hexagonal boron nitride is exfoliated into nanosheets while being preliminarily hydroxylated, reducing the adverse phenomena caused by the aggregation of hexagonal boron nitride and improving the wettability, obtaining hexagonal boron nitride nanosheet powder.

[0067] (2) Add 1.5 g of the hexagonal boron nitride nanosheet powder obtained in step (1) into 150 mL of 5 mol / L sodium hydroxide solution, mix it evenly with a magnetic stirrer, and then perform ultrasonic dispersion treatment. During the ultrasonic dispersion process, the ultrasonic power is 700 W and the ultrasonic time is 25 min. The ultrasonic dispersion treatment is beneficial for the better contact modification of the hexagonal boron nitride nanosheet powder with the sodium hydroxide solution. The mixed solution is poured into a three-necked flask and continuously refluxed in an oil bath at 110 °C for 24 h. The obtained solution is cooled and filtered, and washed with 1 mol / L hydrochloric acid solution and deionized water until the solution is neutral to fully remove the residual sodium hydroxide, and then freeze-dried. The hexagonal boron nitride nanosheet powder is further hydroxylated using the sodium hydroxide hydrothermal method to improve its wettability and dispersibility in aqueous solution, obtaining a modified hexagonal boron nitride carrier.

[0068] This embodiment provides a preparation method of a wear-resistant composite polishing powder, which specifically includes the following steps:

[0069] S1. Add 1.5 g of modified hexagonal boron nitride support to 100 mL of deionized water, add 1.0 g of samarium nitrate hexahydrate, stir to mix evenly, and set aside. Weigh 4.0 g of cerium nitrate hexahydrate and 1.5 g of polyvinylpyrrolidone powder and dissolve them in a mixed solution of 150 mL of ethylene glycol and 10 mL of deionized water. Stir for 1 h, then add the mixed solution of modified hexagonal boron nitride support and samarium nitrate hexahydrate, stir evenly, transfer the solution to a 400 mL stainless steel reaction kettle with a polytetrafluoroethylene inner lining, place it in a microwave hydrothermal reaction tank. During the microwave hydrothermal reaction, control the temperature to keep warm at 75 °C for 0.75 h, and then keep warm at 155 °C for 6.5 h. Under microwave hydrothermal conditions, cerium oxide continuously grows on the modified hexagonal boron nitride support, so that the modified hexagonal boron nitride support is coated inside the cerium oxide. After the reaction, it is naturally cooled to room temperature, and the product is centrifuged and separated, washed 4 times with deionized water and anhydrous ethanol solution in turn, then placed in an oven and dried at 55 °C for 12 h, and calcined in a muffle furnace at 450 °C in an air atmosphere for 2.5 h. Through hydrothermal reaction and calcination treatment, a small amount of samarium oxide is loaded on the modified hexagonal boron nitride support, as the most core component, and the two work together to improve the dispersibility and suspension of cerium oxide polishing powder in the form of doping and support, improve the polishing uniformity and polishing efficiency. The main phase substance cerium oxide completely coats samarium oxide and the modified hexagonal boron nitride support to form a composite structure, enabling cerium oxide to obtain a favorable internal support, effectively enhancing the hardness and chemical stability of the polishing powder, so as to maintain good wear resistance and polishing performance during the polishing process, and obtain a modified hexagonal boron nitride@cerium oxide composite core;

[0070] S2. Dissolve the modified hexagonal boron nitride@cerium oxide composite core described in step S1 in 150 mL of deionized water, ultrasonically disperse for 15 min, add copper nitrate powder, and the addition amount of copper nitrate is 0.35 g. The interaction between copper ions and cerium ions, by forming a redox pair, reduces part of the tetravalent cerium ions to trivalent cerium ions, improving the polishing performance of cerium oxide. Continuously stir for 1.5 h, raise the temperature to 90 °C and stir the solution to dryness. The product is placed in a muffle furnace and calcined at 450 °C in an air atmosphere for 2.5 h. The obtained copper oxide is loaded on the surface of the modified hexagonal boron nitride@cerium oxide composite core to form a wear-resistant and efficiency-enhancing protective layer, further reducing the loss and breakage of cerium oxide during the polishing process, improving the wear resistance. This sandwich-like structure also reduces the agglomeration phenomenon of cerium oxide polishing powder. In addition, it significantly increases the concentration of oxygen vacancies in the abrasive, promotes the bonding of Ce-O-Si bonds, enhances the reaction activity, thereby improving the polishing efficiency and polishing effect, and obtaining a wear-resistant composite polishing powder.

[0071] Example 4

[0072] This embodiment provides a wear-resistant composite polishing powder, which comprises the following components in parts by weight: 100 parts of modified hexagonal boron nitride@cerium oxide composite core and 10 parts of wear-resistant efficiency protection layer.

[0073] The modified hexagonal boron nitride@cerium oxide composite core comprises the following components in parts by weight: 20 parts of modified hexagonal boron nitride carrier, 50 parts of cerium oxide, 20 parts of polyvinylpyrrolidone, and 8 parts of samarium oxide.

[0074] The modified hexagonal boron nitride carrier is prepared by subjecting hexagonal boron nitride to sodium hydroxide-assisted physical ball milling to exfoliate it into nanosheets while preliminarily performing hydroxylation modification, and then further performing hydroxylation modification using the hydrothermal method.

[0075] The wear-resistant efficiency protection layer is a shell material formed by using copper nitrate as a surface modification component and obtaining copper oxide loaded on the core.

[0076] The preparation method of the modified hexagonal boron nitride carrier specifically includes the following steps:

[0077] (1) Add 20 mL of 5 mol / L sodium hydroxide solution, zirconia grinding balls with a mass ratio of 20:1, and hexagonal boron nitride powder into the ball mill tank, control the rotation speed at 400 rpm, the grinding time at 12 h, sieve, subject the obtained hexagonal boron nitride slurry to centrifugation at a centrifugation speed of 2000 rpm and a centrifugation time of 5 min, take the upper suspension, and perform centrifugation again at a centrifugation speed of 10000 rpm and a centrifugation time of 5 min. Freeze-dry the precipitate. Through sodium hydroxide-assisted physical ball milling, hexagonal boron nitride is exfoliated into nanosheets while preliminarily performing hydroxylation modification, reducing the adverse phenomena caused by the agglomeration of hexagonal boron nitride and improving the wettability, thus obtaining hexagonal boron nitride nanosheet powder;

[0078] (2) Add 2.0 g of the hexagonal boron nitride nanosheet powder obtained in step (1) into 150 mL of 5 mol / L sodium hydroxide solution, mix evenly with a magnetic stirrer, and then perform ultrasonic dispersion treatment. During the ultrasonic dispersion process, the ultrasonic power is 800 W and the ultrasonic time is 20 min. The ultrasonic dispersion treatment is beneficial for the better contact modification of the hexagonal boron nitride nanosheet powder with the sodium hydroxide solution. Pour the mixed solution into a three-necked flask and continuously reflux in an oil bath at 120 °C for 24 h. Cool and filter the obtained solution, wash it with 1 mol / L hydrochloric acid solution and deionized water respectively until the solution is neutral to fully remove the residual sodium hydroxide, and then freeze-dry. Further perform hydroxylation modification on the hexagonal boron nitride nanosheet powder by using the sodium hydroxide hydrothermal method to improve its wettability and dispersibility in aqueous solution, thus obtaining the modified hexagonal boron nitride carrier.

[0079] This embodiment provides a method for preparing wear-resistant composite polishing powder, which specifically includes the following steps:

[0080] S1. Add 2.0 g of modified hexagonal boron nitride support to 100 mL of deionized water, add 0.8 g of samarium nitrate hexahydrate, stir to mix evenly, and set aside. Weigh 5.0 g of cerium nitrate hexahydrate and 2.0 g of polyvinylpyrrolidone powder and dissolve them in a mixed solution of 150 mL of ethylene glycol and 10 mL of deionized water. Stir for 1 h, then add the mixed solution of modified hexagonal boron nitride support and samarium nitrate hexahydrate, stir evenly, transfer the solution to a 400 mL stainless steel reaction kettle with a polytetrafluoroethylene inner lining, and place it in a microwave hydrothermal reaction tank. During the microwave hydrothermal reaction, control the temperature to keep warm at 80 °C for 0.5 h, and then keep warm at 160 °C for 6 h. Under the microwave hydrothermal conditions, cerium oxide continuously grows on the modified hexagonal boron nitride support, so that the modified hexagonal boron nitride support is coated inside the cerium oxide. After the reaction, naturally cool to room temperature, centrifuge the product, wash it 5 times with deionized water and anhydrous ethanol solution in sequence, then put it into an oven, dry it at 60 °C for 12 h, and calcine it in a muffle furnace at 500 °C in an air atmosphere for 2 h. Through hydrothermal reaction and calcination treatment, a small amount of samarium oxide is loaded on the modified hexagonal boron nitride support, which is the most core component. The two work together to improve the dispersibility and suspension of cerium oxide polishing powder in the way of doping and support, improve the polishing uniformity and polishing efficiency. The main phase substance cerium oxide completely coats the samarium oxide and the modified hexagonal boron nitride support to form a composite structure, enabling cerium oxide to obtain a favorable internal support, effectively enhancing the hardness and chemical stability of the polishing powder, and thus maintaining good wear resistance and polishing performance during the polishing process, obtaining a modified hexagonal boron nitride@cerium oxide composite core;

[0081] S2. Dissolve the modified hexagonal boron nitride@cerium oxide composite core described in step S1 in 200 mL of deionized water, ultrasonically disperse it for 10 min, add 0.2 g of copper nitrate powder. The interaction between copper ions and cerium ions, by forming a redox pair, reduces part of the tetravalent cerium ions to trivalent cerium ions, improving the polishing performance of cerium oxide. Continuously stir for 1 h, raise the temperature to 90 °C and stir the solution to dryness. Put the product into a muffle furnace and calcine it at 500 °C in an air atmosphere for 2 h. The obtained copper oxide is loaded on the surface of the modified hexagonal boron nitride@cerium oxide composite core to form a wear-resistant and efficiency-enhancing protective layer, further reducing the loss and breakage of cerium oxide during the polishing process, improving the wear resistance. This sandwich-like structure also reduces the agglomeration phenomenon of cerium oxide polishing powder. In addition, it significantly increases the concentration of oxygen vacancies in the abrasive, promotes the combination of Ce-O-Si bonds, enhances the reaction activity, and thus improves the polishing efficiency and polishing effect, obtaining wear-resistant composite polishing powder.

[0082] Comparative Example 1

[0083] This comparative example provides a wear-resistant composite polishing powder, which is different from Example 1 in that the wear-resistant composite polishing powder does not contain a modified hexagonal boron nitride carrier; the modified hexagonal boron nitride carrier is not included in step S1 of the preparation method of the wear-resistant composite polishing powder, and other contents are the same as those in Example 1.

[0084] Comparative Example 2

[0085] This comparative example provides a wear-resistant composite polishing powder, which is different from Example 1 in that the wear-resistant composite polishing powder does not contain samarium oxide; the preparation method of the modified hexagonal boron nitride carrier is the same as that in Example 1; samarium nitrate hexahydrate is not included in step S1 of the preparation method of the wear-resistant composite polishing powder, and other contents are the same as those in Example 1.

[0086] Comparative Example 3

[0087] This comparative example provides a wear-resistant composite polishing powder, which is different from Example 1 in that the wear-resistant composite polishing powder does not contain a wear-resistant efficiency protection layer; the preparation method of the modified hexagonal boron nitride carrier is the same as that in Example 1; the preparation method of the wear-resistant composite polishing powder does not include step S2.

[0088] Experimental Example 1

[0089] Wear Resistance Experiment

[0090] Test samples: The wear-resistant composite polishing powders prepared in Examples 1-4 and Comparative Examples 1-3.

[0091] Test method: Disperse the test samples in deionized water respectively to prepare a suspension with a mass fraction of 1%, adjust the pH value of the suspension to 9.0 with 0.1 mol / L NaOH solution, ultrasonically disperse the above polishing liquid for 5 min before use, and conduct a polishing test on a 2 cm × 2 cm thermal silicon oxide wafer using a Shenyang Kejing UNIPOL-1200S automatic pressure grinding and polishing machine. The polishing parameters are set as follows: the upper disk rotation speed is 80 r / min, the lower disk rotation speed is 120 r / min, the pressure is 1 kg, the polishing time is 3 min, and the polishing liquid flow rate is 100 mL / min. Statistically analyze the central particle size (μm) before and after polishing, and calculate the particle size reduction rate (%) according to the following formula as a reference for the wear resistance of the polishing powder. The larger the reduction rate, the more obvious the particle size change and the poorer the wear resistance:

[0092] Particle size reduction rate (%) = (particle size before polishing - particle size after polishing) / particle size before polishing × 100%

[0093] Figure 3Results graph of particle size reduction rate for Examples 1-4 and Comparative Examples 1-3; as shown in the figure, the particle size reduction rates of Examples 1-4 are 5-9%, all < 10%, indicating relatively strong wear resistance; the particle size reduction rates of Comparative Examples 1-3 are 14-20%, all > 10%, indicating relatively weak wear resistance; the wear-resistant composite polishing powder of Comparative Example 1 does not contain a modified hexagonal boron nitride carrier, and cerium oxide cannot grow on the carrier to form a coating, lacking the support of the internal carrier, which is not conducive to improving hardness and results in relatively weak wear resistance; the wear-resistant composite polishing powder of Comparative Example 2 does not contain samarium oxide, lacking the doping addition of samarium oxide, which is not conducive to improving the compactness and defects of the cerium oxide polishing powder and results in relatively weak wear resistance; the wear-resistant composite polishing powder of Comparative Example 3 does not contain a wear resistance enhancement protection layer, and copper oxide cannot be loaded on the surface of the modified hexagonal boron nitride@cerium oxide composite core, which is not conducive to reducing the breakage of cerium oxide during polishing and results in relatively weak wear resistance.

[0094] Experimental Example 2

[0095] Polishing performance experiment

[0096] Test samples: Wear-resistant composite polishing powders prepared in Examples 1-4 and Comparative Examples 1-3.

[0097] Test method: The test samples were respectively dispersed in deionized water to prepare a suspension with a mass fraction of 1%, and the pH value of the suspension was adjusted to 9.0 with 0.1 mol / L NaOH solution. Before use, the above polishing liquid was ultrasonically dispersed for 5 min. A 2 cm × 2 cm thermal silicon oxide wafer was polished using a Shenyang Kejing UNIPOL-1200S automatic pressure grinding and polishing machine. The polishing parameters were set as follows: the upper disk rotation speed was 80 r / min, the lower disk rotation speed was 120 r / min, the pressure was 1 kg, the polishing time was 3 min, and the polishing liquid flow rate was 100 mL / min; the material removal rate (MRR) was defined by the change in film thickness per unit time. To ensure the accuracy of the data, the mass of the workpiece before and after polishing was weighed three times with an analytical balance with a precision of one ten-thousandth and the average value was taken. The calculation formula is as follows;

[0098] Then, 150 thermal silicon oxide wafers were polished using different test samples for detection. Those with scratches were classified as defective products, and the yield rate (%) was statistically obtained;

[0099] MRR (nm / min) = m 差值 / (ρ × S × t)

[0100] where, m 差值 is the mass difference (g) of the workpiece before and after polishing, ρ is the density of the silicon oxide film (taking the value of 2.2 g / cm 3 ), S is the area of the Si wafer (cm 2 ), and t is the polishing time (min).

[0101] Figure 4 Graphs showing the polishing performance results of Examples 1-4 and Comparative Examples 1-3; as shown in the figure, the removal rates and good product rates of Examples 1-4 are 219.5-235.2 nm / min and 96.6-99.3% respectively, indicating good polishing performance, high polishing removal rate and good product rate; the removal rates and good product rates of Comparative Examples 1-3 are 174.5-201.3 nm / min and 90.0-93.3% respectively, indicating poor polishing performance, low polishing removal rate and good product rate; the wear-resistant composite polishing powder of Comparative Example 1 does not contain modified hexagonal boron nitride carrier, and cannot improve the dispersion of cerium oxide in the form of carrier, increasing the agglomeration in water, thus limiting the polishing efficiency and polishing quality, resulting in poor polishing performance, low polishing removal rate and good product rate; the wear-resistant composite polishing powder of Comparative Example 2 does not contain samarium oxide, and cannot improve the dispersion of cerium oxide in the form of doping, nor can it play the role of promoting the reduction of cerium oxide by samarium oxide, thus unable to improve the polishing efficiency and surface flatness of cerium oxide polishing powder better, resulting in poor polishing performance, low polishing removal rate and good product rate; the wear-resistant composite polishing powder of Comparative Example 3 does not contain wear-resistant and efficiency-enhancing protective layer, and cannot play the active role of copper oxide on cerium oxide, resulting in poor polishing performance, low polishing removal rate and good product rate.

[0102] The above experimental results show that the wear resistance and polishing performance of Examples 1-4 of the present invention are significantly better than those of the samples of Comparative Examples 1-3. Among them, Example 1 using the modified hexagonal boron nitride@cerium oxide composite core and the wear-resistant and efficiency-enhancing protective layer has stronger wear resistance, higher polishing removal rate and good product rate. Cerium oxide grows on the modified hexagonal boron nitride carrier, completely covering the modified hexagonal boron nitride carrier, and doped with samarium oxide loaded on the modified hexagonal boron nitride carrier, improving the dispersion of cerium oxide in the form of doping and carrier, reducing the agglomeration phenomenon in water, improving the polishing uniformity and polishing efficiency. At the same time, the addition of the modified hexagonal boron nitride carrier and samarium oxide makes the cerium oxide polishing powder more dense, reduces defects, improves the hardness of the cerium oxide polishing powder, making it more wear-resistant. Then, the copper oxide obtained by calcination is loaded on the surface of the modified hexagonal boron nitride@cerium oxide composite core to form a sandwich-like inclusion structure, further reducing the loss and breakage of cerium oxide during polishing, improving the wear resistance. At the same time, it also promotes the reduction of some tetravalent cerium ions to trivalent cerium ions, increases the concentration of oxygen vacancies in the abrasive, and promotes the combination of Ce-O-Si bonds, thus improving the polishing efficiency and polishing effect of the cerium oxide polishing powder.

[0103] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made in these embodiments without departing from the principles and spirit of the present invention.

[0104] The present invention and its embodiments have been described above. Such description is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual application is not limited thereto. Generally speaking, if those of ordinary skill in the art are inspired by it and, without departing from the spirit of the present invention, design similar methods and embodiments to this technical solution without creative efforts, they shall fall within the protection scope of the present invention.

Claims

1. A method for preparing a wear-resistant composite polishing powder, characterized in that: The preparation method of the wear-resistant composite polishing powder specifically comprises the following steps: S1. Add 1.0-2.0 g of modified hexagonal boron nitride carrier to 100 mL of deionized water, add 0.8-1.2 g of samarium nitrate hexahydrate, stir to mix evenly, and set aside. Weigh 3.0-5.0 g of cerium nitrate hexahydrate and 1.0-2.0 g of polyvinyl pyrrolidone powder and dissolve them in a mixed solution of 150 mL of ethylene glycol and 10 mL of deionized water, stir for 1 hour, and then add the mixed solution of modified hexagonal boron nitride carrier and samarium nitrate hexahydrate. Stir evenly, transfer the solution to a 400mL polytetrafluoroethylene-lined stainless steel reactor, and place it in a microwave hydrothermal reaction tank. After the reaction is completed, cool it naturally to room temperature, centrifuge the product, wash it with deionized water and anhydrous ethanol solution for 3-5 times, then place it in an oven, dry it at 50-60°C for 12h, and calcine it in a muffle furnace at 400-500°C in an air atmosphere for 2-3h to obtain a modified hexagonal boron nitride@cerium oxide composite core; S2, dissolving the modified hexagonal boron nitride @ cerium oxide composite core material described in step S1 in 100-200 mL of deionized water, ultrasonically dispersing for 10-20 min, adding copper nitrate powder, stirring continuously for 1-2 h, heating to 90 ° C, stirring and evaporating the solution to dryness, placing the product in a muffle furnace, calcining at 400-500 ° C in an air atmosphere for 2-3 h to form a wear-resistant synergistic protective layer, and obtaining a wear-resistant composite polishing powder; The preparation method of the modified hexagonal boron nitride carrier specifically comprises the following steps: (1) Add 20 mL of 5 mol / L sodium hydroxide solution and zirconium oxide grinding balls and hexagonal boron nitride powder in a mass ratio of 20:1 into a ball mill, control the speed to 300-400 rpm, grind for 12-24 h, sieve, centrifuge the obtained hexagonal boron nitride slurry, centrifuge at a speed of 1000-2000 rpm, centrifuge for 5-10 min, take the upper suspension, centrifuge again, centrifuge at a speed of 9000-10000 rpm, centrifuge for 5-10 min, freeze-dry the precipitate to obtain hexagonal boron nitride nanosheet powder; (2) 1.0-2.0 g of the hexagonal boron nitride nanosheet powder described in step (1) is added to 150 mL of 5 mol / L sodium hydroxide solution, mixed evenly with a magnetic stirrer, and then subjected to ultrasonic dispersion treatment. The mixed solution is poured into a three-necked flask and refluxed in an oil bath at 100-120° C. for 24 h. The resulting solution is cooled and filtered, washed with 1 mol / L hydrochloric acid solution and deionized water respectively until the solution is neutral, and then freeze-dried to obtain a modified hexagonal boron nitride carrier.

2. The method for preparing the wear-resistant composite polishing powder according to claim 1, characterized in that: In step S1, during the microwave hydrothermal reaction, the temperature is controlled to be kept at 70-80°C for 0.5-1h, and then kept at 150-160°C for 6-7h.

3. The method for preparing the wear-resistant composite polishing powder according to claim 2, characterized in that: In step S2, the amount of copper nitrate added is 0.2-0.5 g.

4. The method for preparing the wear-resistant composite polishing powder according to claim 3, characterized in that: In step (2), during the ultrasonic dispersion process, the ultrasonic power is 600-800 W and the ultrasonic time is 20-30 min.

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