Method for preparing ceramic microsphere precursor and ceramic microsphere with internal network structure

Abstract

This invention discloses a method for preparing a ceramic microsphere precursor and ceramic microspheres with an internal network structure. The method for preparing the ceramic microsphere precursor includes the following steps: preparing an emulsifier solution; mixing a ceramic substrate component with the emulsifier solution to prepare a ceramic microsphere precursor solution; separating the powder from the solvent in the ceramic microsphere precursor solution to obtain the ceramic microsphere precursor; the ceramic substrate component includes one or more of aluminates, metal chlorides, metal nitrates, and metal sulfates; the emulsifier includes a solvent, an emulsifier, and a surfactant, wherein the solvent is water, and the mass ratio of water, emulsifier, and surfactant is (75-85):(0.45-1.25):(0.0075-0.0325). This method achieves high strength and high temperature resistance in the prepared ceramic microspheres with an internal network structure, and the preparation process does not require the use of large amounts of organic solvents.

Description

Technical Field

[0001] This invention relates to the field of ceramic microsphere technology, specifically to a method for preparing ceramic microspheres with an internal mesh structure and their precursors. Background Technology

[0002] Ceramic microspheres are a special type of structural and functional material, widely researched and applied in piezoelectric fields, aerospace, and marine engineering. Ceramic microspheres are typically prepared using precursors, which are then fabricated via liquid-phase template methods or hydrothermal methods. The resulting ceramic microspheres suffer from low strength and short lifespan, making industrial production difficult and costly. Furthermore, the liquid-phase template method requires large amounts of organic solvents that cannot be recycled, leading to high production costs and severe environmental pollution. Notably, it also results in an amorphous structure for the ceramic microspheres, leading to lower high-temperature resistance during use, thus hindering their widespread application.

[0003] Therefore, how to prepare high-strength, high-temperature resistant ceramic microspheres has become a pressing problem to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing ceramic microsphere precursors, which achieves high strength and high temperature resistance of the prepared ceramic microspheres with internal network structure. The preparation process does not require the use of a large amount of organic solvents, thus avoiding environmental pollution, reducing production costs, and facilitating industrial production.

[0005] According to one aspect of the present invention, a method for preparing a ceramic microsphere precursor is provided, comprising the following steps:

[0006] Prepare emulsifier solutions;

[0007] The ceramic substrate component is mixed with the emulsifier solution to prepare a ceramic microsphere precursor solution.

[0008] The powder in the ceramic microsphere precursor solution is separated from the solvent to obtain the ceramic microsphere precursor;

[0009] The ceramic substrate component includes aluminate and one or more of metal chloride, metal nitrate and metal sulfate.

[0010] The emulsifier solution includes a solvent, an emulsifier, and a surfactant. The solvent is water, and the mass ratio of water, emulsifier, and surfactant is (75-85):(0.45-1.25):(0.0075-0.0325).

[0011] The advantages of this invention over the prior art are that, since the ceramic substrate composition includes one or more of aluminates, metal chlorides, metal nitrates, and metal sulfates, but does not include organic components, it is beneficial for the internally networked ceramic microspheres obtained after subsequent sintering to withstand high temperatures, and the amount of volatiles released during the sintering process is small, which helps to avoid the reduction in the strength of the internally networked ceramic microspheres.

[0012] By using water as the solvent in the emulsifier solution, the environmental pollution and high cost associated with organic solvents are avoided. The emulsifier comprises a solvent, an emulsifier, and a surfactant, with water as the solvent. This results in the vesicles formed in the prepared emulsifier solution having a negatively charged outer surface and a positively charged inner surface. The vesicles contain a mesh-like structure, thus enabling the ceramic microsphere precursor solution to include oxide ceramic microcapsules. These oxide ceramic microcapsules include ceramic substrate components attached to the outer and inner surfaces of the vesicles, with the ceramic substrate components on the inner surface forming a network structure. This results in the final ceramic microspheres with an internal mesh structure, which in turn provides high strength. Furthermore, the preparation process does not require the use of large amounts of organic solvents, avoiding environmental pollution, reducing production costs, and facilitating industrial production.

[0013] Furthermore, the preparation of the emulsifier solution follows these steps:

[0014] At room temperature, emulsifier and surfactant are added to water and stirred at a speed of 1250-1450 r / min to obtain an emulsifier solution.

[0015] The prepared emulsifier solution includes spherical vesicles;

[0016] The outer surface of the vesicle is negatively charged, and the inner surface of the vesicle is positively charged; the interior of the vesicle contains a mesh-like structure.

[0017] Furthermore, the preparation process of the ceramic microsphere precursor solution is as follows: Under negative pressure, ceramic substrate components are added to the emulsifier solution and mixed and stirred for ≥30 min to obtain the ceramic microsphere precursor solution; the pressure of the negative pressure environment is -0.1 MPa to -0.01 MPa;

[0018] The ceramic microsphere precursor solution obtained includes oxide ceramic microcapsules, which include a ceramic substrate component attached to the outer surface of the microcapsule and a ceramic substrate component attached to the inner surface of the microcapsule. The ceramic substrate component attached to the inner surface of the microcapsule has a network structure.

[0019] The beneficial effect of adopting the above technical solution is that by preparing the ceramic microsphere precursor solution under negative pressure, it is beneficial to achieve that the ceramic components in the obtained ceramic microspheres have a crystalline phase structure, which further helps to ensure that the ceramic microspheres with internal network structure can withstand high temperatures during use.

[0020] By rapidly stirring the emulsifier in water, emulsifier vesicles are formed in the water; negatively charged surfactants adhere to the surface of the emulsifier vesicles, and positively charged surfactants adhere to the inside of the emulsifier vesicles; thus, spherical vesicles are included in the emulsifier solution.

[0021] The vesicles have a negatively charged outer surface and a positively charged inner surface; the vesicles contain a mesh-like structure, thereby enabling the positively charged ceramic substrate components to adhere to the outer surface and the inner surface of the vesicles, forming a network structure. The negative pressure environment facilitates the rapid hydrolysis of the positively and negatively charged ceramic substrate components after they adhere to the inner and outer surfaces of the vesicles, forming a cross-linked structure on these surfaces.

[0022] Furthermore, during the preparation of the ceramic microsphere precursor solution, the mixing process of the emulsifier solution and the ceramic substrate components under negative pressure is as follows:

[0023] In a mixing device, the ceramic substrate component is added to the emulsifier solution and stirred. The mixing device is evacuated to achieve a negative pressure state. The gas extracted from the mixing device is condensed by a condenser, and the resulting condensate is added to the mixing device.

[0024] The temperature of the condensate in the condensation device is 5-10℃.

[0025] The beneficial effect of adopting the above technical solution is that the negative pressure device is connected to the mixing device, and the gas is extracted from the mixing device through the negative pressure device to achieve a negative pressure state in the reaction environment of the device; by condensing the gas extracted from the mixing device through the condensing device and adding the resulting condensate to the mixing device, the problem of changes in the material composition in the ceramic microsphere precursor solution caused by negative pressure during the preparation of the ceramic microsphere precursor solution is avoided, thereby avoiding the problem of uneven composition of the ceramic substrate after hydrolysis on the surface of the vesicles.

[0026] Furthermore, the emulsifier includes two or three of the following: octylbenzyl alcohol, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, and polyoxyethylene polyoxypropylene ether block copolymer.

[0027] The beneficial effect of adopting the above technical solution is that the emulsifier molecule chain is long and does not contain polar functional groups, thereby realizing the formation of emulsifier vesicles in water, and the inner surface of the emulsifier vesicle is bound with a positively charged surfactant, and the outer surface is bound with a negatively charged surfactant.

[0028] Furthermore, the surfactant includes sodium dodecylbenzenesulfonate, and also includes hexadecyltrimethylammonium bromide and / or octadecyltrimethylammonium bromide.

[0029] The beneficial effect of adopting the above technical solution is that sodium dodecylbenzenesulfonate adheres to the outer surface of the emulsifier vesicles, and hexadecyltrimethylammonium bromide and / or octadecyltrimethylammonium bromide adhere to the outer surface of the emulsifier vesicles.

[0030] Furthermore, the aluminate includes one of sodium aluminate and potassium aluminate; the metal chloride includes one of aluminum trichloride and calcium chloride; the metal nitrate includes one of aluminum nitrate and calcium nitrate; and the metal sulfate includes one of aluminum sulfate and magnesium sulfate.

[0031] The beneficial effect of adopting the above technical solution is that metal chlorides, metal nitrates, metal sulfates, and metal acetates can combine with the negative charge on the outer surface of the vesicle, while aluminates combine with the negative charge on the inner surface of the vesicle, and form a network structure ceramic within the vesicle.

[0032] Furthermore, the mass ratio of the ceramic substrate component to water is (10-25):(75-85).

[0033] According to another aspect of the present invention, a ceramic microsphere with an internal mesh structure is provided, which is obtained by sintering a ceramic microsphere precursor, wherein the ceramic microsphere precursor is prepared by a method for preparing a ceramic microsphere precursor.

[0034] Furthermore, the internally embedded mesh-structured ceramic microspheres have a submicron-sized spherical structure; the spherical structure contains a mesh-structured ceramic; the internally embedded mesh-structured ceramic microspheres have a heat resistance temperature ≥1800℃; preferably, the internally embedded mesh-structured ceramic microspheres have a heat resistance temperature ≥1850℃.

[0035] The internally embedded mesh-structured ceramic microspheres have a particle size of 0.05-2 μm, a wall thickness of 10-20 nm, and a bulk density of 0.25-0.4 g / cm³. 3 The crushing strength of the ceramic microspheres with internal mesh structure accounting for 5% of the volume is 65-100 MPa; the meaning of the crushing strength of the ceramic microspheres with internal mesh structure accounting for 5% of the volume is the pressure intensity when 5% of the internal mesh structure ceramic microspheres are crushed during the testing of the internal mesh structure ceramic microspheres.

[0036] The advantages of this invention over the prior art are that by using water as the solvent for the emulsifier solution, the environmental pollution and high cost caused by organic solvents are avoided; and the ceramic substrate components do not contain organic components, which is beneficial to the high strength of the obtained ceramic microspheres. At the same time, by combining the preparation of the precursor solution of ceramic microspheres with internal network structure under negative pressure, the ceramic components of the ceramic microspheres with internal network structure are made into a crystalline phase structure, thereby achieving high temperature resistance during use.

[0037] The internally designed ceramic microspheres with a mesh structure contain ceramic with a mesh structure, thereby achieving high strength. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be described below.

[0039] Figure 1 This is a 2µm scanning electron microscope image of the ceramic microspheres with the internal mesh structure of the present invention.

[0040] Figure 2 This is a 200µm electron microscope image of the ceramic microspheres with a built-in mesh structure in this invention. Detailed Implementation

[0041] To better understand the technical solution of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings.

[0042] Example 1:

[0043] In one aspect of this embodiment, a method for preparing a ceramic microsphere precursor is provided, comprising the following steps:

[0044] Prepare an emulsifier solution, wherein the emulsifier solvent includes a solvent, an emulsifier, and a surfactant, wherein the solvent is water, and the mass ratio of water, emulsifier, and surfactant is 80:0.85:0.02;

[0045] The specific steps for preparing an emulsifier solution are as follows: at room temperature, emulsifier and surfactant are added to water and stirred at 1350 r / min to obtain an emulsifier solution, wherein the emulsifier solution includes spherical vesicles;

[0046] The outer surface of the vesicle is negatively charged, and the inner surface of the vesicle is positively charged; the interior of the vesicle contains a mesh-like structure.

[0047] The emulsifiers include octylbenzyl alcohol and polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer;

[0048] The surfactant comprises sodium dodecylbenzenesulfonate and hexadecyltrimethylammonium bromide; the mass ratio of sodium dodecylbenzenesulfonate to hexadecyltrimethylammonium bromide is 1:0.8.

[0049] Preparation of ceramic microsphere precursor solution;

[0050] Under negative pressure, a ceramic substrate component is added to an emulsifier solution and stirred for 32 minutes to obtain a ceramic microsphere precursor solution. The ceramic microsphere precursor solution includes oxide ceramic microcapsules, which contain a ceramic substrate component attached to the outer surface of the microcapsule and a ceramic matrix component attached to the inner surface of the microcapsule. The ceramic substrate component attached to the inner surface of the microcapsule forms a network structure. The pressure of the negative pressure environment is -0.051 MPa. When preparing the ceramic microsphere precursor solution, the mixing process of the emulsifier solution and the ceramic substrate component under negative pressure is as follows: the ceramic substrate component is added to the emulsifier solution and stirred in a mixing device. The mixing device is evacuated to achieve a negative pressure state. The gas extracted from the mixing device is condensed by a condenser, and the resulting condensate is added to the mixing device. The temperature of the condensate in the condenser is 7°C.

[0051] The ceramic substrate component includes aluminate, metal chloride, and metal nitrate; specifically, the aluminate is sodium aluminate; the metal chloride is aluminum trichloride; the metal nitrate is aluminum nitrate; the mass ratio of the ceramic substrate component to water is 20:80; and the mass ratio of potassium aluminate, aluminum trichloride, and aluminum nitrate added is 1:0.8:1.

[0052] The ceramic microsphere precursor solution was centrifuged to obtain the ceramic microsphere precursor.

[0053] In another aspect of this embodiment, a ceramic microsphere with an internal mesh structure is provided, which is obtained by sintering a ceramic microsphere precursor. The ceramic microsphere precursor is prepared by a method for preparing ceramic microsphere precursors.

[0054] After washing, the ceramic microsphere precursor is calcined at 1450°C to obtain the ceramic microspheres with the internal network structure.

[0055] The internally embedded mesh-structured ceramic microspheres have a heat resistance temperature of 1850℃; the internally embedded mesh-structured ceramic microspheres have a submicron-level spherical structure; the spherical structure contains a mesh-structured ceramic.

[0056] The internally embedded mesh-structured ceramic microspheres have a particle size of 0.18 μm, a wall thickness of 15 nm, and a bulk density of 0.32 g / cm³. 3The crushing strength of the ceramic microspheres with a mesh structure, which comprise 5% of the volume, is 85 MPa.

[0057] Example 2:

[0058] The same content as in Example 1 will not be repeated here; the different aspects of this embodiment compared to Example 1 are as follows:

[0059] In one aspect of this embodiment, a method for preparing a ceramic microsphere precursor is provided, comprising the following steps:

[0060] The solvent is water, and the mass ratio of water, emulsifier, and surfactant is 78:0.65:0.0165.

[0061] The specific steps for preparing an emulsifier solution are as follows: at room temperature, add the emulsifier and surfactant to water and stir at 1400 r / min to obtain an emulsifier solution;

[0062] The emulsifier includes octylbenzyl alcohol and polyoxyethylene polyoxypropylene ether block copolymer;

[0063] The surfactant includes sodium dodecylbenzenesulfonate and octadecyltrimethylammonium bromide; the mass ratio of sodium dodecylbenzenesulfonate to octadecyltrimethylammonium bromide is 1:0.75.

[0064] Under a negative pressure environment of -0.021 MPa, ceramic substrate components are added to the emulsifier solution and mixed and stirred for 35 minutes to obtain a ceramic microsphere precursor solution; the temperature of the condensate in the condensation device is 6℃.

[0065] The ceramic substrate components include aluminates, metal chlorides, and metal sulfates; specifically, the aluminate is potassium aluminate; the metal chloride is aluminum trichloride; and the metal sulfate is aluminum sulfate; the mass ratio of added potassium aluminate, aluminum trichloride, and aluminum sulfate is 1:0.6:0.7.

[0066] The mass ratio of the ceramic substrate component to water is 12:78.

[0067] In another aspect of this embodiment, a ceramic microsphere with an internal mesh structure is provided; the ceramic microsphere precursor is calcined at a temperature of 1350°C to obtain the ceramic microsphere with the internal mesh structure.

[0068] The internally embedded mesh-structured ceramic microspheres have a heat resistance temperature of 1800℃; the particle size of the internally embedded mesh-structured ceramic microspheres is 0.85μm, the wall thickness of the internally embedded mesh-structured ceramic microspheres is 16nm, and the bulk density of the internally embedded mesh-structured ceramic microspheres is 0.35g / cm³. 3 The crushing strength of the ceramic microspheres with a mesh structure that comprise 5% of the volume is 95 MPa.

[0069] Example 3:

[0070] The same content as in Example 1 will not be repeated here; the different aspects of this embodiment compared to Example 1 are as follows:

[0071] In one aspect of this embodiment, a method for preparing a ceramic microsphere precursor is provided, comprising the following steps:

[0072] The solvent is water, and the ratio of water, emulsifier, and surfactant is 82:0.55:0.0085;

[0073] The specific steps for preparing an emulsifier solution are as follows: at room temperature, add the emulsifier and surfactant to water and stir at 1300 r / min to obtain an emulsifier solution;

[0074] The emulsifiers include octylbenzyl alcohol, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, and polyoxyethylene polyoxypropylene ether block copolymer;

[0075] The surfactant includes sodium dodecylbenzenesulfonate and octadecyltrimethylammonium bromide; the mass ratio of sodium dodecylbenzenesulfonate to octadecyltrimethylammonium bromide is 1:0.78.

[0076] Under a negative pressure environment of -0.091 MPa, ceramic substrate components are added to the emulsifier solution and mixed and stirred for 35 minutes to obtain a ceramic microsphere precursor solution; the temperature of the condensate in the condensation device is 8℃.

[0077] The ceramic substrate component includes aluminate and metal chloride; specifically, the aluminate is sodium aluminate; the metal chloride is aluminum trichloride; the mass ratio of potassium aluminate, aluminum trichloride, and zirconium acetate added is 1:1.2. The mass ratio of the ceramic substrate component to water is 18:82.

[0078] In another aspect of this embodiment, a ceramic microsphere with an internal mesh structure is provided; the ceramic microsphere precursor is calcined at a temperature of 1400°C to obtain the ceramic microsphere with an internal mesh structure.

[0079] The internally embedded mesh-structured ceramic microspheres have a heat resistance temperature of 1820℃; the particle size of the internally embedded mesh-structured ceramic microspheres is 0.15μm, the wall thickness of the internally embedded mesh-structured ceramic microspheres is 12nm, and the bulk density of the internally embedded mesh-structured ceramic microspheres is 0.3g / cm³. 3 The crushing strength of the ceramic microspheres with a mesh structure, which comprise 5% of the volume, is 90 MPa.

[0080] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, the above-described features have similar functions to (but are not limited to) those disclosed in this application.

Claims

1. A method for preparing a ceramic microsphere precursor, characterized by, The method comprises the following steps: Preparation of an emulsifier solution; Mixing ceramic base material components with the emulsifier solution to prepare a ceramic microsphere precursor solution; Separating the powder in the ceramic microsphere precursor solution from the solvent to obtain the ceramic microsphere precursor; The ceramic base material components include a meta-aluminate and one or more of a metal chloride, a metal nitrate, and a metal sulfate; The emulsifier solution includes a solvent, an emulsifier, and a surfactant, wherein the solvent is water, and the mass ratio of water, the emulsifier, and the surfactant is (75-85):(0.45-1.25):(0.0075-0.0325); The emulsifier solution is prepared by the following steps: At room temperature, the emulsifier and the surfactant are added to water, and stirring is performed at a rotation speed of 1250-1450 r / min to obtain the emulsifier solution; The emulsifier solution prepared includes vesicles with a spherical structure; The outer surface of the vesicles is negatively charged, and the inner surface of the vesicles is positively charged; the vesicles contain a grid structure inside; The ceramic microsphere precursor solution is prepared by the following process: ceramic base material components are added to the emulsifier solution and mixed and stirred under a negative pressure environment for ≥30 min to obtain the ceramic microsphere precursor solution; the pressure of the negative pressure environment is -0.1 MPa to -0.01 MPa; The ceramic microsphere precursor solution prepared includes oxide ceramic microcapsules, which include ceramic base material components attached to the outer surface of the vesicles and ceramic base material components attached to the inner surface of the vesicles, and the ceramic base material components attached to the inner surface of the vesicles are in a network structure.

2. The method for preparing the ceramic microsphere precursor according to claim 1, characterized in that, When the ceramic microsphere precursor solution is prepared, the mixing process of the emulsifier solution and the ceramic base material components under a negative pressure environment is as follows: The emulsifier solution is stirred with the ceramic base material components in a mixing device, a negative pressure state is achieved by vacuumizing the mixing device through a negative pressure device, and the gas extracted from the mixing device is condensed through a condensing device, and the obtained condensate is added to the mixing device; The temperature of the condensate in the condensing device is 5-10℃.

3. The method for preparing the ceramic microsphere precursor according to claim 1, characterized in that, The emulsifier includes two or three of octoxinol, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, and polyoxyethylene polyoxypropylene ether block copolymer.

4. The method for preparing the ceramic microsphere precursor according to claim 1, characterized in that, The surfactant includes sodium dodecyl benzene sulfonate, and also includes cetyl trimethyl ammonium bromide and / or octadecyl trimethyl ammonium bromide.

5. The method for preparing the ceramic microsphere precursor according to claim 1, characterized in that, The meta-aluminate includes one of sodium meta-aluminate and potassium meta-aluminate; the metal chloride includes one of aluminum trichloride and calcium chloride; the metal nitrate includes one of aluminum nitrate and calcium nitrate; and the metal sulfate includes one of aluminum sulfate and magnesium sulfate.

6. The method for preparing the ceramic microsphere precursor according to claim 1, characterized in that, The mass ratio of the ceramic base material components to water is (10-25):(75-85).

7. A ceramic microsphere having a network structure inside, characterized by comprising a ceramic shell and a network structure inside the ceramic shell. The ceramic microsphere precursor is prepared by the method for preparing a ceramic microsphere precursor according to any one of claims 1-6.

8. The ceramic microspheres having a reticulated structure according to claim 7, wherein, The ceramic microsphere with the built-in network structure has a sub-micron spherical structure, and the spherical structure is provided with a network structure ceramic. The built-in net structure ceramic microsphere uses a heat-resistant temperature of ≥1800℃; The inner net structure ceramic microspheres have a particle size of 0.05-1 μm, a wall thickness of 10-20 nm, and a bulk density of 0.25-0.4 g / cm 3 The crushing strength of the inner net structure ceramic microspheres accounting for 5% in volume is 65-100 MPa.

Images