Fe-coated SiO2-coated CeO2 magnetic composite abrasive particle as well as preparation method and application thereof

Abstract

The invention discloses a Fe-coated SiO2-coated CeO2 magnetic composite abrasive particle and a preparation method and application thereof, and relates to the technical field of polishing abrasive particle production, the Fe-coated SiO2-coated CeO2 magnetic composite abrasive particle is prepared through a homogeneous precipitation method, a polishing solution prepared from the composite abrasive particle is good in dispersity, and the polishing efficiency and the polishing quality can be remarkably improved when the composite abrasive particle is applied to glass polishing.

Description

Technical Field

[0001] The present invention relates to the technical field of polishing abrasive production, and specifically to an Fe@SiO 2 @CeO 2 magnetic composite abrasive and its preparation method and application. Background Art

[0002] Glass materials are widely used in modern industry, especially in the fields of construction, electronics, optics, etc. The performance requirements for glass materials are becoming increasingly strict. High hardness, excellent light transmittance and wear resistance are key indicators, and the surface quality directly affects the final performance and use effect of glass products. Therefore, surface processing has become the core link in the glass preparation process, and polishing is an important step to improve surface flatness and smoothness. High-efficiency and precision polishing technology can significantly improve the surface performance of glass, making it meet the requirements of various high-end applications.

[0003] Magnetorheological polishing (MRP) is an efficient and precise surface processing technology. It suspends abrasives in a magnetorheological fluid and uses a magnetic field to control the distribution and movement of the abrasives to achieve high-precision polishing of the glass surface. The magnetorheological polishing fluid mainly consists of magnetic particles, non-magnetic abrasives, additives and solvents. Among them, carbonyl iron is widely used in magnetorheological polishing due to its high magnetic saturation intensity and good magnetic responsiveness, providing precise control over the movement of the abrasives. Cerium oxide, as a non-magnetic abrasive, has become an ideal material for glass polishing due to its excellent polishing ability and chemical stability.

[0004] In conventional magnetorheological polishing fluids, non-magnetic abrasives often have the problem of uneven distribution, which leads to instability in the polishing process and thus affects the final quality of the glass surface. Uneven abrasive distribution is likely to cause local under-polishing or over-polishing, resulting in an increase in surface roughness and failing to achieve the expected high-precision polishing effect. Therefore, improving the stability and uniform distribution of abrasives in the magnetorheological polishing process is of great significance for reducing the surface roughness of glass and improving the polishing quality. Summary of the Invention

[0005] In order to solve the problems of the existing technology, the purpose of the present invention is to overcome the deficiencies of the existing technology and provide a preparation method and application of Fe@SiO 2 @CeO 2 magnetic composite abrasives. Compared with the non-magnetic abrasives of the currently commonly used magnetorheological polishing fluids, it has a magnetic particle core to stably control the polishing behavior, thereby improving the overall stability of magnetorheological polishing. When this magnetorheological polishing fluid is applied to the field of glass surface processing, it can significantly improve the processing efficiency and surface processing quality to meet the increasingly stringent requirements for glass finishing.

[0006] One of the objectives of the present invention is to provide a method for preparing Fe@SiO 2 @CeO 2 magnetic composite abrasive grains, which is prepared by the homogeneous precipitation method, and the steps of the preparation method are as follows:

[0007] S1. Add the first raw materials into deionized water, mix and stir to obtain modified carbonyl iron powder. The first raw materials include carbonyl iron powder and a modifier;

[0008] S2. Add the second raw materials to the modified carbonyl iron powder, mix and heat and stir to obtain Fe@SiO

[0009] magnetic composite abrasive grains; the second raw materials include an organic solvent, a Si source material and a precipitating agent; 2 S3. Add the Fe@SiO

[0010] magnetic composite abrasive grains and the third raw materials into deionized water, mix and heat and stir to obtain a precipitate; the third raw materials include a Ce source material and a precipitating agent. 2 Preferably, the organic solvent is absolute ethanol.

[0011] Preferably, the molar ratio of the precipitating agent in step S2 to the second raw materials is 1:(1-15); the molar ratio of the precipitating agent in step S3 to the third raw materials is 1:(1-15).

[0012] Preferably, the precipitating agent selected in S2 is ammonia water, and the precipitating agent selected in S3 is urea.

[0013] Preferably, the Si source material is tetraethyl orthosilicate, and the Ce source material is ammonium cerium nitrate.

[0014] Preferably, the mixture in step S3 is mechanically stirred at a speed of 300 rpm and reacted at 80 °C for 24 hours.

[0015] Preferably, the precipitate obtained in step S3 is purified by magnetic separation to obtain Fe@SiO

[0016] @CeO 2 @CeO 2 magnetic composite abrasive grains; the magnetic separation includes transferring the precipitate to a centrifuge tube, using an external magnet to attract magnetic particles outside, separating the cerium source and non-magnetic precipitate, and washing repeatedly 3-5 times until the solution is colorless and transparent.

[0017] Another objective of the present invention is to provide Fe@SiO 2 @CeO 2 magnetic composite abrasive grains prepared by the above preparation method. The coating amount of cerium oxide, i.e., CeO 2and Fe@SiO 2 The molar ratio is (20 - 80):(80 - 20).

[0018] The third object of the present invention is to provide an application of the above-prepared Fe@SiO 2 @CeO 2 magnetic composite abrasive grains, and the Fe@SiO 2 @CeO 2 magnetic composite abrasive grains are applied to the polishing field of glass materials.

[0019] The steps for preparing a polishing liquid with the Fe@SiO 2 @CeO 2 magnetic composite abrasive grains are as follows: adding the Fe@SiO 2 @CeO 2 magnetic composite abrasive grains, carbonyl iron powder and an additive into deionized water to prepare a Fe@SiO 2 @CeO 2 magnetorheological polishing liquid.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] The present invention prepares Fe@SiO 2 @CeO 2 magnetic composite abrasive grains with abrasive grains driven by a magnetic core by successively using the co-precipitation method and the homogeneous precipitation method to coat silicon oxide and cerium oxide layers on the surface of carbonyl iron powder. The preparation method of the abrasive grains is simple and can be scaled up for industrial production.

[0022] The Fe@SiO 2 @CeO 2 magnetic composite abrasive grains prepared by the present invention can improve the stability of the magnetorheological polishing process due to the presence of a magnetic core drive, can perform high-precision machining on glass materials, achieve the purpose of high-precision machining, can significantly reduce the surface roughness, and improve the polishing quality.

[0023] The Fe@SiO 2 @CeO 2 magnetic composite abrasive grain polishing liquid prepared by the present invention is applied to the magnetorheological polishing of glass materials, and can effectively improve the surface roughness of the substrate glass. Description of the Drawings

[0024] Figure 1 Scanning electron microscope image of the prepared Fe@SiO 2 @CeO 2 magnetic composite abrasive grains. Specific Embodiment Methods

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention 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. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0027] A preparation method of Fe@SiO 2 @CeO 2 magnetic composite abrasive grains is prepared by the homogeneous precipitation method, and the steps of the preparation method are as follows:

[0028] S1. Add the first raw materials into deionized water, mix and stir to obtain modified carbonyl iron powder. The first raw materials include carbonyl iron powder and a modifier;

[0029] S2. Add the second raw materials to the modified carbonyl iron powder, mix and heat and stir to obtain Fe@SiO 2 magnetic composite abrasive grains; the second raw materials include an organic solvent, an Si source substance and a precipitating agent; the organic solvent is anhydrous ethanol. In this step, ammonia water is selected as the precipitating agent, and the molar ratio of the precipitating agent to the second raw materials is 1:(1-15). The Si source substance is tetraethyl orthosilicate. The Fe@SiO 2 magnetic composite abrasive grains are magnetically separated. Specifically, after transferring the precipitate to a centrifuge tube, use an external magnet to attract magnetic particles outside to separate non-magnetic precipitates, and wash repeatedly 3-5 times until the solution is colorless and transparent.

[0030] S3. Add the Fe@SiO 2 magnetic composite abrasive grains and the third raw materials into deionized water, mechanically stir the mixture at a speed of 300 rpm, and react at 80 °C for 24 hours to obtain a precipitate; the obtained precipitate is purified by magnetic separation to obtain Fe@SiO 2 @CeO 2 magnetic composite abrasive grains; the magnetic separation includes transferring the precipitate to a centrifuge tube, using an external magnet to attract magnetic particles outside to separate the cerium source and non-magnetic precipitates, and washing repeatedly 3-5 times until the solution is colorless and transparent.

[0031] The third raw materials include a Ce source substance and a precipitating agent. In this step, urea is selected as the precipitating agent, and the molar ratio of the precipitating agent to the third raw materials is 1:(1-15). The Ce source substance is ammonium cerium nitrate.

[0032] The Fe@SiO 2 @CeO 2 magnetic composite abrasive grains prepared by this application contain CeO 2and Fe@SiO 2 The molar ratio of them is (20-80):(80-20); it is applied to the polishing field of glass materials.

[0033] For easy understanding, first, the English nouns mentioned in the following text are explained

[0034] Sa: Abbreviation of surface roughness

[0035] Fe: Iron carbonyl

[0036] CeO 2 : Cerium oxide

[0037] SiO 2 : Silicon oxide

[0038] SDS: Sodium dodecyl sulfate

[0039] FSC-X: x = 1-5, representing Fe@SiO with different coating amounts 2 @CeO 2 Magnetic composite abrasive grains, where CeO 2 : Fe@SiO 2 = x:1 (x = 0.25, 0.5, 1, 2, 4).

[0040] Example 1

[0041] This example provides a preparation method of Fe@SiO 2 @CeO 2 Magnetic composite abrasive grains. Among them, the formula is: iron carbonyl powder (20 g), tetraethyl orthosilicate (TOES, 58 ml), ammonium cerium nitrate (6.16 g), urea (5.32 g), sodium dodecyl sulfate (SDS, 3 g)

[0042] The preparation steps are as follows:

[0043] (1) Add the iron carbonyl powder and SDS in the formula to a flask containing 50 ml of deionized water, and mechanically stir at a speed of 300 rpm at room temperature for 30 min to obtain SDS-modified iron carbonyl powder.

[0044] (2) Add 90 ml of absolute ethanol (V 无水乙醇 :V 去离子水 = 9:5) to the solution in step (1), and then add 10 ml of TOES and 20 ml of ammonia water. Continue to mechanically stir at a speed of 300 rpm for 2 h.

[0045] (3) During the stirring process in step (2), add 4 ml of TEOS to the flask every 10 min, and a total of 48 ml is added.

[0046] (4) Transfer the solution obtained in step (3) to a centrifuge bottle. The precipitate obtained by magnetic separation is Fe@SiO 2 , and wash it 3 times repeatedly with deionized water in a centrifuge tube.

[0047] (5) Place the pure Fe@SiO 2 abrasives obtained in step (4) in an oven at 60 °C to dry and obtain Fe@SiO 2 powder.

[0048] (6) Take 32 g of the Fe@SiO 2 composite abrasives obtained in step (5), place them in a 500 m three-necked flask, add 200 ml of deionized water, then place the three-necked flask in an 80 °C oil bath, and carry out mechanical stirring at a rotation speed of 300 rpm.

[0049] (7) Then add ammonium cerium nitrate solution and urea solution to the flask in step (6), and carry out mechanical stirring at a rotation speed of 300 rpm for 24 h.

[0050] (8) After the reaction in step (7) ends, stop mechanical stirring, and remove the flask from the oil bath and let it return to room temperature.

[0051] (9) Transfer the solution in step (8) to a centrifuge bottle, and magnetically separate to obtain pure Fe@SiO 2 @CeO 2 magnetic composite abrasives. Then place the precipitate in an oven at 60 °C to dry and obtain FSC-1 powder.

[0052] Add the prepared FSC-1 composite abrasives to an alkaline solution to prepare a magnetorheological polishing fluid. Among them, the mass fraction of Fe@SiO 2 @CeO 2 composite abrasives is 4 wt%, the mass fraction of carbonyl iron powder is 64.5 wt%, the mass fraction of sodium hexametaphosphate is 2 wt%, and the mass fraction of deionized water is 29.4%. The prepared Fe@SiO 2 @CeO 2 composite abrasive magnetorheological polishing fluid is FSC-1 polishing fluid (polishing fluid 1).

[0053] Example 2

[0054] The ratio of each substance in the formula is changed. Specifically:

[0055] Carbonyl iron powder (20 g), tetraethyl orthosilicate (TOES, 58 ml), ammonium cerium nitrate (12.32 g), urea (10.64 g), sodium dodecyl sulfate (SDS, 3 g)

[0056] The steps are the same as those in Example 1.

[0057] FSC-2 and FSC-2 polishing liquid (polishing liquid 2) were prepared.

[0058] There are still several points to note in the above embodiments:

[0059] ① The raw materials selected are small crystal particles with a particle size of about 2 mm, and they are prepared into a powder state by manual grinding, that is, in steps (1) and (5), the raw materials are crushed into a powder. In actual implementation, powder raw materials can be directly selected for preparation. Of course, it is also better to appropriately grind to break up the agglomerates first;

[0060] ② In step (6), deionized water ensures that Fe@SiO 2 The magnetic composite abrasive grains can be stably dispersed during the reaction. In the above several embodiments, it is 200 ml.

[0061] ③ Centrifugal separation is a method for solid-liquid separation. In actual operation, according to the different particle sizes and quantities of the materials, the rotation speed and time can be adjusted;

[0062] ④ The drying method is drying in an air environment. For the washed Fe 3 O 4 @CeO 2 particles, a drying condition of 60 °C is adopted. However, in actual operation, according to the physical and chemical properties of the material, it can be known that the material can be dried under the conditions from room temperature to 120 °C without causing changes in the material properties, and with the change of conditions such as the quantity of the material,

[0063] the drying time can also be appropriately adjusted;

[0064] ⑤ In this embodiment, the Fe 3 O 4 @CeO 2 composite abrasive grains are configured into a polishing liquid with a mass fraction of 4 wt%, but in actual operation, the concentration of the abrasive grains can be changed to adjust the polishing rate.

[0065] Comparative Example 1

[0066] This comparative example provides a preparation method of pure CeO 2 abrasive grains. Among them,

[0067] the composition in the formula changes. Specifically, it is ammonium cerium nitrate (18.42 g) and urea (16 g). The steps are the same as those in Example 1, except that Fe@SiO 2 magnetic composite abrasive grains are not added.

[0068] CeO 2 abrasive grains were prepared, and pure CeO 2 magnetorheological polishing liquid (Comparative Example 1).

[0069] Comparative Example 2

[0070] This comparative example provides a method for preparing a polishing liquid of Fe@SiO 2 composite abrasive grains, and the steps are basically the same as those in Example 2. The difference lies in that:

[0071] Fe@SiO 2 @CeO 2 The composite abrasive grains are replaced with Fe@SiO 2 abrasive grains, and Fe@SiO 2 magnetorheological polishing liquid (Comparative Example 2) is prepared.

[0072] Polishing experiments were carried out using Polishing Liquid 1, Polishing Liquid 2, Comparative Example 1, and Comparative Example 2 respectively, as follows:

[0073] Polishing object: ordinary soda-lime glass sheet, Sa 0 = 2.25nm;

[0074] The polishing conditions for the polishing test are as follows:

[0075] Polishing machine: friction and wear tester modified with an external magnetic field;

[0076] Workpiece: an ordinary soda-lime glass sheet with a diameter of 50 mm and a thickness of 2 mm;

[0077] Polishing pressure: 5 N;

[0078] Workpiece rotation speed: 80 rpm;

[0079] Polishing time: 60 min.

[0080] After polishing, the ordinary soda-lime glass sheet was washed and dried in the order of cleaning solution, deionized water, and ethanol, and the surface roughness of the substrate glass sheet before and after polishing was measured by a 3D surface profiler.

[0081] The polishing effects of each polishing liquid on the ordinary soda-lime glass sheet are shown in Table 1,

[0082] Compared with the unpolished soda-lime glass sheet, the surface roughness of the polished sample Among them, Sa is the surface roughness corresponding to the sample treated with the polishing liquid represented by its subscript.

[0083] Table 1 Polishing effects of each polishing liquid on the substrate glass

[0084]

[0085] As can be seen from Table 1, compared with Fe@SiO 2 , Fe@SiO 2@CeO 2 Due to the coating of CeO 2 , the ability to remove rough peaks during the polishing process is improved, making the surface roughness of the substrate after polishing with Fe@SiO 2 @CeO 2 lower. Compared with pure CeO 2 , Fe 3 O 4 @CeO 2 Due to the confinement of internal magnetic particles, the abrasive grains are evenly distributed on the surface of the glass substrate, further reducing the surface roughness of the substrate. And a glass substrate polished with FSC-1 has obtained a high-quality smooth surface (Sa = 1.18 nm).

[0086] In summary, the composite abrasive grains provided by the present invention, namely Fe@SiO 2 @CeO 2 , have higher polishing efficiency compared with non-magnetic CeO 2 . At the same time, they can maintain a good surface roughness while ensuring a relatively high material removal rate, achieving the purpose of high-efficiency precision machining.

[0087] 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, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing Fe@SiO2@CeO2 magnetic composite abrasive particles, characterized in that: The preparation is carried out by homogeneous precipitation method, and the steps of the preparation method are as follows: S1. Adding a first raw material into deionized water, mixing and stirring to obtain modified carbonyl iron powder, wherein the first raw material includes carbonyl iron powder and a modifier; S2, adding a second raw material to the modified carbonyl iron powder, mixing and heating and stirring to obtain Fe@SiO2 magnetic composite abrasive particles; the second raw material includes an organic solvent, a Si source material and a precipitant; S3, adding Fe@SiO2 magnetic composite abrasive and a third raw material into deionized water, mixing and heating and stirring to obtain a precipitate; the third raw material includes a Ce source material and a precipitant.

2. The method for preparing Fe@SiO2@CeO2 magnetic composite abrasive according to claim 1, characterized in that: The organic solvent is anhydrous ethanol.

3. The method for preparing Fe@SiO2@CeO2 magnetic composite abrasive according to claim 1, characterized in that: The molar ratio of the precipitant to the second raw material in step S2 is 1:(1-15); the molar ratio of the precipitant to the third raw material in step S3 is 1:(1-15).

4. The method for preparing Fe@SiO2@CeO2 magnetic composite abrasive particles according to claim 1, characterized in that: In step S2, the precipitant is ammonia water, and in step S3, the precipitant is urea.

5. The method for preparing Fe@SiO2@CeO2 magnetic composite abrasive according to claim 1, characterized in that: The Si source material is tetraethyl orthosilicate, and the Ce source material is ammonium cerium nitrate.

6. The method for preparing Fe@SiO2@CeO2 magnetic composite abrasive particles according to claim 1, characterized in that: In step S3, the mixture was mechanically stirred at 300 rpm and reacted at 80° C. for 24 hours.

7. The method for preparing Fe@SiO2@CeO2 magnetic composite abrasive according to claim 1, characterized in that: The precipitate obtained in step S3 is purified by magnetic separation to obtain Fe@SiO2@CeO2 magnetic composite abrasive; the magnetic separation includes transferring the precipitate to a centrifuge tube, using an external magnet to attract magnetic particles externally, separating the cerium source and non-magnetic precipitate, and repeatedly washing 3-5 times until the solution is colorless and transparent.

8. A Fe@SiO2@CeO2 magnetic composite abrasive, characterized in that: Prepared by the preparation method described in any one of claims 1-7; and the molar ratio of CeO2 and Fe@SiO2 in the Fe@SiO2@CeO2 magnetic composite abrasive is: (20-80): (80-20).

9. An application of Fe@SiO2@CeO2 magnetic composite abrasive, characterized in that: The Fe@SiO2@CeO2 magnetic composite abrasive is applied in the field of polishing of glass materials.

10. The use according to claim 9, characterized in that: The step of preparing the polishing liquid with the Fe@SiO2@CeO2 magnetic composite abrasive is as follows: adding the Fe@SiO2@CeO2 magnetic composite abrasive, carbonyl iron powder and additives into deionized water to prepare the Fe@SiO2@CeO2 magnetorheological polishing liquid.

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