Composite dispersing type nanometer aluminum oxide slurry with good dispersity in aqueous solution and preparation method of composite dispersing type nanometer aluminum oxide slurry

Abstract

The invention relates to composite dispersing type nanometer aluminum oxide slurry with good dispersity in an aqueous solution and a preparation method thereof.The composite dispersing type nanometer aluminum oxide slurry is obtained by adding nanometer aluminum oxide powder into dispersion liquid, the dispersion liquid is prepared from a composite dispersing agent, the composite dispersing agent comprises a dispersing agent A and a dispersing agent B, wherein the dispersing agent A is a mixture of bentonite and deionized water; the dispersing agent B is a mixture of a high-molecular polymer and deionized water. Through multiple dispersion effects of the composite dispersant, the prepared nanometer alumina slurry has the advantages of good dispersibility, stable solution system, short time and energy consumption and the like.

Description

Technical Field

[0001] The present invention relates to the fields of new materials and dispersion technology. Specifically, it particularly relates to a composite dispersion type nano-aluminum oxide slurry with good dispersibility in aqueous solution and a preparation method thereof. Background Art

[0002] Nanomaterials can be nanoparticles with extremely small sizes. The proportion of surface atoms in the total atoms is relatively large, making the nanoparticles have a very high surface energy. Due to their extremely small particle size and high specific surface area, nanomaterials have a strong tendency to agglomerate. This agglomeration phenomenon will not only affect the excellent properties of nanomaterials, such as reducing their chemical reaction activity, optical properties, electrical properties, etc., but also hinder their uniform dispersion and effective utilization in practical applications. Therefore, how to effectively solve the agglomeration problem of nano-aluminum oxide and achieve its stable dispersion in different media has become one of the key challenges in the development of aluminum oxide materials in the nano field, which has also promoted the in-depth research and wide application of dispersants in this field.

[0003] Patent CN112812288B discloses a preparation method of a nano-aluminum oxide dispersant and a nano-aluminum oxide dispersant. In this invention, a highly dispersible amorphous nano-aluminum oxide dispersant is added to the nano-aluminum oxide solution, and the cationic monomer in the dispersant is used as a hydrophilic group for reaction, making it easier for the dispersant to adsorb on the nanoparticle surface to improve the dispersibility and stability of nano-aluminum oxide in aqueous solution.

[0004] Patent CN112194915A discloses a preparation method of an alumina pre-dispersant. In this preparation method, high-purity alumina powder is added to a dispersion liquid, the immersion time is 300 - 600 min and it is ground in a sand mill to obtain an alumina aqueous solution, and through demagnetization and adjusting the viscosity of the alumina aqueous solution, an alumina pre-dispersion liquid is prepared. This method has a long immersion time and requires the use of a sand mill, having the problems of time-consuming and energy-consuming. Summary of the Invention

[0005] Aiming at the problems existing in the existing nano-aluminum oxide dispersion process, such as complex process, time-consuming and energy-consuming, and poor dispersion stability, the present invention provides a composite dispersion type nano-aluminum oxide slurry with good dispersibility in aqueous solution and a preparation method thereof.

[0006] Different from the prior art, the present invention uses a composite dispersion technology in which two dispersants act together. The preparation process of the dispersant is relatively simple and less time-consuming and energy-consuming.

[0007] The technical means adopted by the present invention are as follows:

[0008] A composite dispersed nano-aluminum oxide slurry with good dispersibility in aqueous solution, which is obtained by adding nano-aluminum oxide powder into a dispersion liquid. The dispersion liquid is prepared from a composite dispersant, and the composite dispersant includes dispersant A and dispersant B. Among them, dispersant A is a mixture of bentonite and deionized water; dispersant B is a mixture of a high molecular polymer and deionized water.

[0009] Further, dispersant A and deionized water are mixed at a mass ratio of 1:1 - 1:20.

[0010] Further, dispersant B and deionized water are mixed at a mass ratio of 1:1 - 10:1.

[0011] Further, the mass concentration of dispersant A in the dispersion liquid is 0.1% - 20%, and the mass concentration of dispersant B is 0.1% - 20%.

[0012] Further, the particle size of the nano-aluminum oxide powder is 200 - 800 nm.

[0013] Further, the purity of aluminum oxide in the nano-aluminum oxide powder is 99.9% - 99.99%. The mass concentration of nano-aluminum oxide powder in the nano-aluminum oxide solution is 5% - 20%.

[0014] Further, the bentonite is an organically modified flaky silicate. The organic modification material can be one or several of γ-aminopropyltriethoxysilane, epoxy resin, polyurethane, polymethyl methacrylate, cetyltrimethylammonium bromide, sodium dodecyl sulfate, polyethylene glycol.

[0015] Further, the high molecular polymer is sodium polyacrylate.

[0016] The present invention also discloses a preparation method of the above composite dispersed nano-aluminum oxide slurry, which includes the following steps:

[0017] Step 1: Mix bentonite and deionized water, and stir with a high-speed centrifuge for 40 - 60 min at room temperature (15 - 25 °C) to obtain the activated dispersant A;

[0018] Step 2: Mix the high molecular polymer and deionized water, and stir magnetically for 5 - 20 min at room temperature (15 - 25 °C) to obtain the activated dispersant B;

[0019] Step 3: Add the activated dispersant A and dispersant B to deionized water, and mix to obtain a dispersion liquid;

[0020] Step 4: Add the nano-aluminum oxide powder to the dispersion liquid, and adjust the pH of the aluminum oxide solution to 8.0 - 11.0;

[0021] Step 5: Stir and shake in an ultrasonic oscillation device at room temperature for 10 - 20 min to ensure that the nano-aluminum oxide powder is evenly suspended in the aqueous solution, and prepare a well-dispersed aluminum oxide dispersion.

[0022] Further, in Step 1, the rotational speed of the high-speed centrifuge is 3000 - 10000 r / min.

[0023] The present invention provides a method for preparing a composite-dispersed nano-aluminum oxide slurry with good dispersibility in an aqueous solution. On the one hand, through the interaction between the layered structure of dispersant A and nano-aluminum oxide particles, a network structure relationship is gradually formed to improve the dispersion stability; on the other hand, a large number of negative charges are generated by the ionization of dispersant B and adsorbed on the surface of nano-aluminum oxide, resulting in an electrostatic repulsive force between the particles. At the same time, as a high molecular polymer, the molecular chain of dispersant B extends in the solution and forms a steric hindrance layer around the particles after adsorption on the particle surface, causing the particles to be far away from each other.

[0024] Through the multiple dispersion effects of the composite dispersant, the prepared nano-aluminum oxide slurry has the advantages of good dispersibility, stable solution system, short time and energy consumption. Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is a columnar comparison chart of the absolute value of the zeta potential of the nano-aluminum oxide slurry in each embodiment.

[0027] Figure 2 It is a broken-line comparison chart of the particle size distribution of the nano-aluminum oxide slurry in each embodiment. Detailed Embodiments

[0028] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The following will refer to the drawings and combine the embodiments to detail the present invention.

[0029] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are only a part rather than all of the embodiments of the present invention. The description of at least one exemplary embodiment below is actually only illustrative and in no way limits the present invention and its application or use. 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 scope of protection of the present invention.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments of the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0031] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for the sake of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods and devices should be regarded as part of the description. In all the examples shown and discussed herein, any specific values should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, further discussion thereof is not required in subsequent drawings.

[0032] In the description of the present invention, it should be understood that the orientation terms such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom", etc. generally refer to the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description. Without contrary description, these orientation terms do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus cannot be construed as limiting the scope of protection of the present invention. The orientation terms "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0033] For ease of description, spatial relative terms, such as "above", "over", "on the upper surface", "upper", etc., may be used herein to describe the spatial positional relationship of one device or feature to other devices or features as shown in the figures. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, a device described as "above" or "over" other devices or structures will then be positioned "below" or "under" the other devices or structures. Thus, the exemplary term "above" can include both orientations of "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the corresponding explanations for the spatial relative descriptions used herein will be made accordingly.

[0034] In addition, it should be noted that the use of terms such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. Without further statement, the above terms have no special meaning, and thus should not be construed as limiting the protection scope of the present invention.

[0035] An embodiment of the present invention discloses a composite dispersion type nano-aluminum oxide slurry with good dispersibility in an aqueous solution, which is obtained by adding nano-aluminum oxide powder to a dispersion liquid. The dispersion liquid is prepared from a composite dispersant, and the composite dispersant includes dispersant A and dispersant B. Among them, dispersant A is a mixture of bentonite and deionized water; dispersant B is a mixture of a high molecular polymer and deionized water.

[0036] The present invention belongs to the field of manufacturing polishing liquids in chemical mechanical polishing. By effectively mixing the common suspending agent bentonite in coatings with a high molecular polymer as a new composite dispersant suitable for the polishing liquid system, a nano-aluminum oxide slurry with good dispersibility is prepared, which has the advantages of low cost, good dispersibility, less time and energy consumption, and stable solution system.

[0037] Further, dispersant A and deionized water are mixed in a mass ratio of 1:9.

[0038] Further, dispersant B and deionized water are mixed in a mass ratio of 5:1.

[0039] Further, the mass concentration of dispersant A in the dispersion liquid is 0.1%-20%. When the mass concentration of the dispersant is lower than 0.1%, the dispersion effect is not obvious. When the concentration of the dispersant is higher than 20%, the content of the dispersant is relatively high, and the viscosity of the nano-aluminum oxide slurry increases.

[0040] In the embodiments of the present invention, dispersant A exchanges or adsorbs ions on the surface of the flaky silicate with organic molecules through organic modification, introducing organic groups into the silicate structure. The flaky silicate gradually forms a continuous and interconnected network structure, which can effectively disperse the alumina powder. When dispersant B adsorbs on the surface of nano-alumina, it generates an electrostatic repulsive force and at the same time forms a steric hindrance to keep the slurry having good suspension.

[0041] The mass concentration of dispersant B is 0.1%-20%. When the mass concentration of the dispersant is lower than 0.1% or higher than 20%, the dispersion effect is not obvious.

[0042] Furthermore, the particle size of the nano-alumina powder is 200-800 nm.

[0043] Furthermore, the purity of alumina in the nano-alumina powder is 99.9%-99.99%. The mass concentration of nano-alumina powder in the nano-alumina solution is 5%-20%.

[0044] Furthermore, the bentonite is an organically modified flaky silicate.

[0045] Furthermore, the polymer is sodium polyacrylate.

[0046] The present invention also discloses a preparation method of the above composite dispersed nano-alumina slurry, including the following steps:

[0047] Step 1: Mix the bentonite with deionized water and stir with a high-speed centrifuge at room temperature of 20°C for 40-60 min to obtain the activated dispersant A;

[0048] Step 2: Mix the polymer with deionized water and stir magnetically at room temperature of 20°C for 5-20 min to obtain the activated dispersant B;

[0049] Step 3: Add the activated dispersant A and dispersant B to deionized water and mix to obtain a dispersion;

[0050] Step 4: Add the nano-alumina powder to the dispersion and adjust the pH of the alumina solution to 8.0-11.0;

[0051] Step 5: Stir and shake in an ultrasonic oscillation device at room temperature for 10-20 min to ensure that the nano-alumina powder is evenly suspended in the aqueous solution and prepare a well-dispersed alumina dispersion.

[0052] Furthermore, in step 1, the speed of the high-speed centrifuge is 3000-10000 r / min.

[0053] To further illustrate the present invention, the following describes in detail a method for preparing a composite dispersed nano-alumina slurry with good dispersibility in an aqueous solution provided by the present invention in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0054] Example 1

[0055] Step 1: Mix the organically modified flaky silicate and deionized water at a mass ratio of 1:9, and stir with a high-speed centrifuge at 3600 r / min for 50 min at room temperature of 20°C to obtain the activated dispersant A;

[0056] Step 2: Mix the polymer and deionized water at a mass ratio of 5:1, and stir magnetically for 10 min at room temperature of 20°C to obtain the activated dispersant B;

[0057] Step 3: Add the activated dispersant A with a mass concentration of 0.5% and dispersant B with a mass concentration of 0.5% to 890 g of deionized water, and mix to obtain a dispersion;

[0058] Step 4: Add nano-alumina powder with a particle size of 300 nm and a mass fraction of 10% to the dispersion obtained in Step 3, and adjust the pH of the alumina solution to 9;

[0059] Step 5: Stir and shake in an ultrasonic oscillation device at room temperature for 15 min to ensure that the nano-alumina powder is uniformly suspended in the aqueous solution, and prepare 1 L of alumina dispersion.

[0060] The absolute value of the zeta potential of the nano-alumina slurry is 50.33 mV, and the D50 measured by the particle size distribution is 315 nm.

[0061] Example 2

[0062] Step 1: Mix the organically modified flaky silicate and deionized water at a mass ratio of 1:9, and stir with a high-speed centrifuge at 10000 r / min for 60 min at room temperature of 20°C to obtain the activated dispersant A;

[0063] Step 2: Mix the polymer and deionized water at a mass ratio of 5:1, and stir magnetically for 20 min at room temperature of 20°C to obtain the activated dispersant B;

[0064] Step 3: Add the activated dispersant A with a mass concentration of 20% and dispersant B with a mass concentration of 20% to 400 g of deionized water, and mix to obtain a dispersion;

[0065] Step 4: Add nano-alumina powder with a particle size of 300 nm and a mass fraction of 20% to the dispersion obtained in Step 3), and adjust the pH of the alumina solution to 11;

[0066] Step 5: Stir and oscillate in an ultrasonic oscillation device at room temperature for 20 min to ensure that the nano-aluminum oxide powder is evenly suspended in the aqueous solution, and prepare 1 L of aluminum oxide dispersion liquid.

[0067] The absolute value of the zeta potential of the nano-aluminum oxide slurry is 42.68 mV, and the D50 measured by the particle size distribution is 387 nm.

[0068] Example 3

[0069] Step 1: Mix the organically modified flaky silicate and deionized water at a mass ratio of 1:9, and stir at 3000 r / min in a high-speed centrifuge for 40 min at room temperature of 20 °C to obtain the activated dispersant A;

[0070] Step 2: Mix the polymer and deionized water at a mass ratio of 5:1, and stir magnetically for 5 min at room temperature of 20 °C to obtain the activated dispersant B;

[0071] Step 3: Add the activated dispersant A with a mass concentration of 0.1% and dispersant B with a mass concentration of 0.1% to 948 g of deionized water, and mix to obtain a dispersion liquid;

[0072] Step 4: Add nano-aluminum oxide powder with a particle size of 300 nm and a mass fraction of 5% to the dispersion liquid obtained in step 3), and adjust the pH of the aluminum oxide solution to 8;

[0073] Step 5: Stir and oscillate in an ultrasonic oscillation device at room temperature for 10 min to ensure that the nano-aluminum oxide powder is evenly suspended in the aqueous solution, and prepare 1 L of aluminum oxide dispersion liquid.

[0074] The absolute value of the zeta potential of the nano-aluminum oxide slurry is 45.46 mV, and the D50 measured by the particle size distribution is 392 nm.

[0075] Example 4

[0076] Step 1: Mix the organically modified flaky silicate and deionized water at a mass ratio of 1:9, and stir at 3600 r / min in a high-speed centrifuge for 50 min at room temperature of 20 °C to obtain the activated dispersant A;

[0077] Step 2: Mix the polymer and deionized water at a mass ratio of 5:1, and stir magnetically for 10 min at room temperature of 20 °C to obtain the activated dispersant B;

[0078] Step 3: Add the activated dispersant A with a mass concentration of 3% and dispersant B with a mass concentration of 5% to 820 g of deionized water, and mix to obtain a dispersion liquid;

[0079] Step 4: Add nano-aluminum oxide powder with a particle size of 300 nm and a mass fraction of 10% to the dispersion liquid obtained in step 3, and adjust the pH of the aluminum oxide solution to 9;

[0080] Step 5: Stir and oscillate in an ultrasonic oscillation device at room temperature for 15 min to ensure that the nano-aluminum oxide powder is uniformly suspended in the aqueous solution, and prepare 1 L of aluminum oxide dispersion.

[0081] The absolute value of the zeta potential of the nano-aluminum oxide slurry is 45.34 mV, and the D50 measured by the particle size distribution is 365 nm.

[0082] Example 5

[0083] Step 1: Mix the organically modified flaky silicate and deionized water at a mass ratio of 1:9, and stir at 10,000 r / min in a high-speed centrifuge for 60 min at room temperature of 20 °C to obtain the activated dispersant A;

[0084] Step 2: Mix the polymer and deionized water at a mass ratio of 5:1, and stir magnetically for 20 min at room temperature of 20 °C to obtain the activated dispersant B;

[0085] Step 3: Add the activated dispersant A with a mass concentration of 10% and dispersant B with a mass concentration of 7% to 630 g of deionized water, and mix to obtain a dispersion;

[0086] Step 4: Add nano-aluminum oxide powder with a particle size of 300 nm and a mass fraction of 20% to the dispersion obtained in step 3), and adjust the pH of the aluminum oxide solution to 11;

[0087] Step 5: Stir and oscillate in an ultrasonic oscillation device at room temperature for 20 min to ensure that the nano-aluminum oxide powder is uniformly suspended in the aqueous solution, and prepare 1 L of aluminum oxide dispersion.

[0088] The absolute value of the zeta potential of the nano-aluminum oxide slurry is 39.87 mV, and the D50 measured by the particle size distribution is 401 nm.

[0089] Example 6

[0090] Step 1: Mix the organically modified flaky silicate and deionized water at a mass ratio of 1:9, and stir at 3,000 r / min in a high-speed centrifuge for 40 min at room temperature of 20 °C to obtain the activated dispersant A;

[0091] Step 2: Mix the polymer and deionized water at a mass ratio of 5:1, and stir magnetically for 5 min at room temperature of 20 °C to obtain the activated dispersant B;

[0092] Step 3: Add the activated dispersant A with a mass concentration of 16% and dispersant B with a mass concentration of 11% to 680 g of deionized water, and mix to obtain a dispersion;

[0093] Step 4: Add nano-aluminum oxide powder with a particle size of 300 nm and a mass fraction of 5% into the dispersion obtained in step 3), and adjust the pH of the aluminum oxide solution to 8.

[0094] Step 5: Stir and oscillate in an ultrasonic oscillation device at room temperature for 10 min to ensure that the nano-aluminum oxide powder is evenly suspended in the aqueous solution, and prepare 1 L of aluminum oxide dispersion.

[0095] The absolute value of the zeta potential of the nano-aluminum oxide slurry is 38.75 mV, and the D50 measured by the particle size distribution is 407 nm.

[0096] Comparative Example 1

[0097] The method used is the same as that in Example 1. The difference from Example 1 is that only dispersant A with a mass concentration of 1% is added in step 3).

[0098] The absolute value of the zeta potential of the nano-aluminum oxide slurry is 33.69 mV, and the D50 measured by the particle size distribution is 457 nm.

[0099] Comparative Example 2

[0100] The method used is the same as that in Example 1. The difference from Example 1 is that only dispersant B with a mass concentration of 1% is added in step 3.

[0101] The absolute value of the zeta potential of the nano-aluminum oxide slurry is 21.56 mV, and the D50 measured by the particle size distribution is 493 nm.

[0102] In the examples of the present invention, a nano particle size and zeta potential analyzer (ZS90) is used to detect the dispersibility of the nano-aluminum oxide slurry. The final results are as Figure 1 and Figure 2 shown. It can be seen that compared with a single dispersant, the effect of using a composite dispersant to disperse the nano-aluminum oxide slurry proposed by the present invention is better. Its zeta potential is significantly increased and in a good stable stage. The repulsion between nano-aluminum oxides is enhanced, and the dispersibility in the polishing liquid is improved. At the same time, the value of D50 in the particle size distribution is closer to the particle size of the nano-aluminum oxide itself, further proving that the dispersion effect of the composite dispersant is better than that of the single dispersant.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite dispersed nano-alumina slurry with good dispersibility in aqueous solution, characterized in that: The slurry is obtained by adding nano alumina powder into a dispersion liquid, wherein the dispersion liquid is prepared by a composite dispersant, and the composite dispersant comprises a dispersant A and a dispersant B, wherein the dispersant A is a mixture of bentonite and deionized water; and the dispersant B is a mixture of a high molecular polymer and deionized water.

2. The composite dispersed nano-alumina slurry with good dispersibility in aqueous solution according to claim 1, characterized in that: Dispersant A is mixed with deionized water in a mass ratio of 1:1-1:

20.

3. The composite dispersed nano-alumina slurry with good dispersibility in aqueous solution according to claim 1, characterized in that: Dispersant B is mixed with deionized water in a mass ratio of 1:1-10:

1.

4. The composite dispersed nano-alumina slurry with good dispersibility in aqueous solution according to claim 1, characterized in that: The mass concentration of dispersant A in the dispersion is 0.1%-20%, and the mass concentration of dispersant B is 0.1%-20%.

5. The composite dispersed nano-alumina slurry with good dispersibility in aqueous solution according to claim 1, characterized in that: The particle size of nano alumina powder is 200-800nm.

6. The composite dispersed nano-alumina slurry with good dispersibility in aqueous solution according to claim 1, characterized in that: The purity of alumina in the nano alumina powder is 99.9%-99.99%, and the mass concentration of the nano alumina powder in the nano alumina solution is 5%-20%.

7. The composite dispersed nano-alumina slurry with good dispersibility in aqueous solution according to claim 1, characterized in that: The bentonite is an organic modified sheet silicate.

8. The composite dispersed nano-alumina slurry with good dispersibility in aqueous solution according to claim 1, characterized in that: The high molecular polymer is polyacrylic acid sodium salt.

9. A method for preparing a composite dispersed nano-alumina slurry with good dispersibility in an aqueous solution, characterized in that: The steps include: Step 1, mixing bentonite with deionized water, stirring in a high-speed centrifuge for 40-60 minutes at 15-25° C., to obtain an activated dispersant A; Step 2, mixing the high molecular polymer with deionized water, and magnetically stirring for 5-20 minutes at 15-25° C. to obtain an activated dispersant B; Step 3, adding the activated dispersant A and dispersant B into deionized water, and mixing to obtain a dispersion; Step 4, adding nano alumina powder to the dispersion, and adjusting the pH of the alumina solution to 8.0-11.0; Step 5: Stir in an ultrasonic oscillation device at room temperature for 10-20 minutes to ensure that the nano-alumina powder is evenly suspended in the aqueous solution to prepare a nano-alumina dispersion with good dispersibility.

10. The composite dispersed nano-alumina slurry with good dispersibility in aqueous solution according to claim 1, characterized in that: In step 1, the speed of the high-speed centrifuge is 3000-10000 r / min.

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