Preparation method of nitride ceramic microsphere precursor and nitride ceramic microsphere

Abstract

The invention discloses a preparation method of a nitride ceramic microsphere precursor and a nitride ceramic microsphere, the preparation method of the nitride ceramic microsphere precursor comprises the following steps: preparing a nitrogen-based emulsifier solution, the nitrogen-based emulsifier solution comprises a solvent and an emulsifier, the solvent is water, and the ratio of the water to the emulsifier is (55-75): (0.3-0.45); adding a ceramic base material component into the nitrogen-based emulsifier, and mixing to prepare a nitride ceramic microsphere precursor solution; the ceramic base material component comprises one or more of metal chlorate, metal nitrate and metal sulfate; in a negative pressure environment, powder in the nitride ceramic microsphere precursor solution is separated from a solvent, and a nitride ceramic microsphere precursor is obtained; the prepared nitride ceramic microspheres are small in particle size and resistant to high temperature, and a large number of organic solvents do not need to be adopted in the preparation process.

Description

Technical Field

[0001] The invention relates to the technical field of nitride ceramic microspheres, and in particular to a nitride ceramic microsphere precursor and a preparation method thereof. Background Art

[0002] Hollow nitride ceramic microspheres are widely used in aerospace, stealth and other fields due to their small particle size, large specific surface area, strong surface adsorption, light weight and high temperature resistance.

[0003] Due to the characteristics of their application fields, nitride ceramic microspheres are required to have high temperature resistance. However, at present, nitride ceramic microspheres are usually obtained by sintering precursors prepared by methods such as liquid phase template method and hydrothermal method. The hydrothermal method introduces the problems of high pressure reaction, difficulty in industrial production and high cost to nitride ceramic microspheres. The liquid phase template method requires a large amount of organic solvents. On the one hand, the organic solvents cannot be recycled, resulting in high production costs and serious environmental pollution. On the other hand, the ceramic in the nitride ceramic microspheres is an amorphous structure, and the high temperature resistance is low during use, which affects the application.

[0004] Therefore, there is an urgent need in the art for a method of producing nitride ceramic microspheres that is low in difficulty, low in cost, has little or no pollution to the environment, and is resistant to high temperatures. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing nitride ceramic microspheres and their precursors, so that the prepared nitride ceramic microspheres have small particle size and high temperature resistance, do not need to use a large amount of organic solvents during the preparation process, avoid environmental pollution and have low cost, thereby realizing industrial production.

[0006] According to one aspect of the present invention, a method for preparing a nitride ceramic microsphere precursor is provided, comprising the following steps:

[0007] A nitrogen-based emulsifier solution is prepared from raw materials including water, an emulsifier and a nitrogen-containing compound, wherein the mass ratio of water, the emulsifier and the nitrogen-containing compound is (55-75): (0.3-0.45): (15-30);

[0008] Adding ceramic substrate components to the nitrogen-based emulsifier and mixing them to prepare a nitride ceramic microsphere precursor solution;

[0009] The ceramic substrate component includes one or more of metal chlorides, metal nitrates, and metal sulfates;

[0010] The powder in the nitride ceramic microsphere precursor solution is separated from the solvent to obtain the nitride ceramic microsphere precursor.

[0011] The beneficial effects of the present invention over the prior art are that the nitrogen-based emulsifier solution includes a solvent and an emulsifier, and the solvent is water, thereby avoiding the problem of environmental pollution and high cost caused by the organic solvent; the nitride ceramic microsphere precursor solution is prepared, and the added ceramic substrate component includes one or more of metal chlorides, metal nitrates, and metal sulfates, and the ceramic base component does not include organic salts, thereby helping to avoid the problem of reduced strength of the ceramic microspheres caused by non-volatilization of organic matter in the subsequent sintering process, and most importantly, it is beneficial for the ceramic in the nitride ceramic microspheres obtained after sintering to have a crystalline phase structure, thereby increasing the use temperature of the nitride ceramic microspheres.

[0012] Further, the preparation of the nitrogen-based emulsifier solution comprises the following steps:

[0013] Heat water to 40-75°C, then add an emulsifier, stir at a speed of 1250-1450 r / min for 12-20 minutes to form emulsified vesicles with a stable hollow spherical structure, add a nitrogen-containing compound and continue stirring, then adjust the pH to pH=8-9 to obtain a transparent white emulsified nitrogen-containing emulsified vesicle solution; stop stirring, let stand, and obtain the nitrogen-based emulsifier solution after primary pre-reaction.

[0014] The beneficial effect of adopting the technical solution in the previous step is that by adding a small amount of emulsifier to water and stirring quickly, the emulsifier forms emulsified vesicles with stable hollow spherical structures, and the nitrogen-containing compound is evenly attached to the surface of the emulsified vesicles. The pH value of the solution is adjusted to 8-9, so that the nitrogen-containing compound has a high binding strength on the surface of the emulsified vesicles. Then, by standing, the nitrogen-containing compound is combined with the emulsifier and undergoes primary pre-reaction to obtain a nitrogen-based emulsifier. Then, after the emulsifier vesicles are broken, the nitrogen-based emulsifier is evenly dispersed in water, and finally a nitrogen-based emulsifier solution is obtained.

[0015] Further, the preparation of the nitride ceramic microsphere precursor solution includes the following steps: adding the ceramic substrate component to the nitrogen-based emulsifier solution under a negative pressure environment, stirring at a speed of 1250-1450r / min to form nitrogen-based emulsified vesicles, adjusting the pH to obtain ceramic-based composite nitrogen element emulsified vesicles after a secondary pre-reaction, adding a surfactant to obtain a nitride ceramic microsphere precursor solution; the pressure of the negative pressure environment is -0.1MPa to -0.01MPa. Preferably, after the nitrogen-based emulsified vesicles are formed, the pH is adjusted to 6.5-7.5.

[0016] The beneficial effect of adopting the previous technical solution is that by preparing the ceramic microsphere precursor solution under a negative pressure environment, it is beneficial to promote the efficient hydrolysis of the ceramic-based components to form metal hydroxides attached to the surface of the nitrogen-based emulsified vesicles, and under negative pressure, the nitrogen-containing elements can more effectively react with the ceramic-based components to shorten the reaction time, which is beneficial to the ceramic in the nitride ceramic microspheres obtained after subsequent sintering to have a crystalline phase structure; at the same time, it improves production efficiency.

[0017] The ceramic substrate component is added to the nitrogen-based emulsifier solution and then stirred at a high speed, thereby obtaining nitrogen-containing emulsified vesicles in water, wherein the ceramic substrate component is evenly distributed on the surface of the nitrogen-containing emulsified vesicles, and the pH is adjusted to achieve a higher bonding strength between the nitrogen-containing compound and the ceramic substrate component than between the nitrogen-containing compound and the emulsifier; and a surfactant is added to form surfactant microspheres with a non-polar interior and a non-polar exterior in water, thereby achieving uniform dispersion of the ceramic-based composite nitrogen element emulsified vesicles between the surfactant microspheres, which is further beneficial to achieving the strength of the ceramic-based composite nitrogen element emulsified vesicles. The ceramic-based composite nitrogen emulsified vesicles include ceramic-based composite nitrogen microcapsules and emulsifier vesicles attached to the inside of the ceramic-based composite nitrogen microcapsules. The surfactant microspheres are beneficial to avoiding the rupture of the ceramic-based composite nitrogen microcapsules, improving their strength, and are beneficial to achieving small and uniform ceramic-based composite nitrogen microcapsules, and achieving partial or complete rupture of the emulsifier vesicles and dispersion into water, but the ceramic-based composite nitrogen microcapsules are not damaged and remain intact, which is also beneficial to avoiding the problem of increased surface porosity of the nitride ceramic microspheres caused by the large-scale volatilization of the emulsifier during subsequent drying and sintering, thereby avoiding the reduction of the surface density of the nitride ceramic microspheres.

[0018] Furthermore, a nitride ceramic microsphere precursor solution is prepared. When preparing the nitride ceramic microsphere precursor solution, the mixing process of the nitrogen-based emulsifier solution and the ceramic substrate component under a negative pressure environment is as follows: the ceramic substrate component is added to the nitrogen-based emulsifier solution in a mixing device and stirred, the mixing device is evacuated by a negative pressure device to achieve a negative pressure state, 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°C.

[0019] The beneficial effect of adopting the previous technical solution is that the negative pressure device is connected to the mixing device, and the negative pressure device is used to extract gas from the mixing device to achieve a negative pressure state of the reaction environment in the mitigation device; the gas extracted from the mixing device is condensed through a condensing device and the obtained condensate is added to the mixing device, thereby avoiding the problem of changes in the material components of the nitride ceramic microsphere precursor solution due to negative pressure during the preparation of the nitride ceramic microsphere precursor solution, thereby avoiding the problem of uneven ceramic substrate components after hydrolysis attached to the surface of the ceramic-based composite nitrogen element microcapsule.

[0020] Furthermore, the emulsifier includes two or three of octoxynol, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, and polyoxyethylene polyoxypropylene ether block copolymer.

[0021] The beneficial effect of adopting the previous technical solution is that the emulsifier vesicles are formed in water by the emulsifier, and the emulsifier vesicles are conducive to having a strong binding strength with the nitrogen-containing compound under certain conditions, and after adjusting the conditions, the binding strength between the emulsifier vesicles and the nitrogen-containing compound is lower than the binding strength between the ceramic-based composite nitrogen element microcapsules and the nitrogen-containing compound.

[0022] Furthermore, the surfactant includes one or more of hexadecyltrimethylammonium bromide, octadecyltrimethylammonium bromide, and sodium dodecylbenzenesulfonate.

[0023] The beneficial effect of adopting the above technical solution is that surfactant microspheres with non-polar interior and polar exterior are formed in the aqueous solution.

[0024] Furthermore, the nitrogen-containing compound is one or more of urea, melamine, dimethylaminonitrogen, and ethylenediamine.

[0025] Furthermore, the preparation of the nitride ceramic microsphere precursor solution also includes the following steps:

[0026] After adding the surfactant, graphite and / or carbon powder are added to obtain a nitride ceramic microsphere precursor solution; preferably, the mass ratio of graphite and / or carbon powder to the ceramic substrate component is (10-15): (1-5).

[0027] The beneficial effect of adopting the above technical solution is that by adding graphite and / or carbon powder, it adheres to the surface of the ceramic-based composite nitrogen element emulsified vesicles, and then adheres to the surface of the ceramic-based composite nitrogen element microcapsules, which helps to avoid the oxidation of nitrogen-containing compounds during the sintering process.

[0028] Further, the mass ratio of the ceramic substrate component to water is (10-15): (55-75);

[0029] The surfactant accounts for 0.05%-0.25% of the mass of the ceramic substrate component.

[0030] The beneficial effect of adopting the above technical solution is that the preparation of nitride microspheres is achieved while reducing the addition of organic matter.

[0031] According to another aspect of the present invention, a nitride ceramic microsphere is provided, wherein the nitride ceramic microsphere is obtained by sintering a nitride ceramic microsphere precursor, and the nitride ceramic microsphere precursor is prepared by the preparation method of the nitride ceramic microsphere precursor; preferably, the nitride ceramic microsphere precursor is calcined in a nitrogen or inert gas atmosphere to obtain the nitride ceramic microsphere; the calcination temperature is 1300-1600°C.

[0032] The nitride ceramic microspheres have a submicron hollow spherical structure; the nitride ceramic microspheres include nitrogen;

[0033] The nitride ceramic microspheres can withstand high temperatures of over 1965°C during use, and preferably, the use temperature can reach over 1980°C.

[0034] The particle size of the nitride ceramic microspheres is 0.05-20 μm, the wall thickness of the nitride ceramic microspheres is 10-25 nm, and the packing density of the nitride ceramic microspheres is 0.25-0.4 g / cm 3 ; The crushing strength of nitride ceramic microspheres that account for 5% of the volume is 58-75MPa; Preferably, the particle size of the nitride ceramic microspheres is 0.05-0.09μm, and the crushing strength of nitride ceramic microspheres that account for 5% of the volume is 58-68MPa. The crushing strength of nitride ceramic microspheres that account for 5% of the volume means the pressure strength when nitride ceramic microspheres are crushed when 5% of the volume is tested.

[0035] The beneficial effects of the present invention over the prior art are that the nitrogen-based emulsifier solution includes a solvent and an emulsifier, and the solvent is water, thereby avoiding the problem of environmental pollution and high cost caused by the organic solvent; the nitride ceramic microsphere precursor solution is prepared, and the added ceramic substrate component includes one or more of metal chlorides, metal nitrates, and metal sulfates, and the ceramic base component does not include organic salts, thereby helping to avoid the problem of reduced strength of the ceramic microspheres caused by non-volatilization of organic matter in the subsequent sintering process, and most importantly, it is beneficial for the ceramic in the nitride ceramic microspheres obtained after sintering to have a crystalline structure, thereby increasing the use temperature of the nitride ceramic microspheres.

[0036] The nitride ceramic microspheres have small particle sizes and high crushing strength when crushed to account for 5% of the volume of the ceramic microspheres. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required to be used in the embodiments of the present invention will be described below.

[0038] Figure 1 This is an electron microscope image of the nitride ceramic microspheres of the present invention. DETAILED DESCRIPTION

[0039] In order to better understand the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments and the accompanying drawings of the specification.

[0040] Embodiment 1:

[0041] In one aspect of the present embodiment, a method for preparing a nitride ceramic microsphere precursor is provided, comprising the following steps: preparing a nitrogen-based emulsifier solution, wherein the nitrogen-based emulsifier solution comprises a solvent, an emulsifier, and a nitrogen-containing compound, wherein the solvent is water, and the mass ratio of water, the emulsifier, and the nitrogen-containing compound is 63:0.36:26; the emulsifier comprises octoxynol and a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer;

[0042] The method for preparing a nitrogen-based emulsifier solution comprises the following steps: heating water to 56°C, then adding an emulsifier, stirring at a rotation speed of 1350 r / min for 16 minutes to form emulsified vesicles with a stable hollow spherical structure, adding a nitrogen-containing compound and continuing to stir, and then adjusting the pH to obtain a transparent white emulsified nitrogen-containing emulsified vesicle solution; when the pH value of the solution is 8.5, stopping stirring and standing the solution to obtain a nitrogen-based emulsifier solution after a primary pre-reaction; the nitrogen-containing compounds are urea and melamine.

[0043] The method comprises the following steps:

[0044] The ceramic substrate component is added to the nitrogen-based emulsifier solution, and the mixture is stirred at a speed of 1350 r / min to form nitrogen-based emulsified vesicles. The pH is adjusted to obtain ceramic-based composite nitrogen element emulsified vesicles after a secondary pre-reaction; a surfactant is added to obtain a nitride ceramic microsphere precursor solution; the pH is adjusted to 7.2 after the nitrogen-based emulsified vesicles are formed; specifically, the ceramic substrate component is added to the nitrogen-based emulsifier solution in a mixing device and stirred, the mixing device is evacuated by a negative pressure device to achieve a negative pressure state, the gas extracted from the mixing device is condensed by a condensing device, and the obtained condensate is added to the mixing device; the temperature of the condensate in the condensing device is 8° C.; and the pressure of the negative pressure environment is -0.051 MPa.

[0045] The surfactant includes hexadecyltrimethylammonium bromide; the ceramic substrate component includes metal chloride and metal nitrate; specifically calcium chloride and aluminum nitrate (aluminum nitrate nonahydrate);

[0046] The mass ratio of the ceramic substrate component, the nitrogen-containing compound and water is 12:64; the surfactant accounts for 0.15% of the mass of the ceramic substrate component.

[0047] The powder and the solvent in the nitride ceramic microsphere precursor solution are separated by filtering to obtain the nitride ceramic microsphere precursor.

[0048] In another aspect of the present embodiment, a nitride ceramic microsphere is provided, wherein the nitride ceramic microsphere is obtained by sintering a nitride ceramic microsphere precursor, and the nitride ceramic microsphere precursor is prepared by the preparation method of the nitride ceramic microsphere precursor; and the nitride ceramic microsphere precursor is also washed and then calcined in a nitrogen atmosphere to obtain the nitride ceramic microsphere; the calcination temperature is 1400°C.

[0049] The nitride ceramic microspheres have a submicron hollow spherical structure; the nitride ceramic microspheres include nitrogen;

[0050] The nitride ceramic microspheres can withstand high temperatures of over 1965° C. during use.

[0051] The particle size of the nitride ceramic microspheres is 0.08 μm, the wall thickness of the nitride ceramic microspheres is 17 nm, and the bulk density of the nitride ceramic microspheres is 0.32 g / cm 3 ; The crushing strength of nitride ceramic microspheres that account for 5% by volume is 66MPa.

[0052] Embodiment 2:

[0053] The same contents as those in Example 1 are not described in detail here. The differences between this embodiment and Example 1 are as follows:

[0054] In one aspect of the present embodiment, a method for preparing a nitride ceramic microsphere precursor is provided. In the process of preparing the nitride ceramic microsphere precursor solution, the following steps are also included:

[0055] The ceramic substrate component is added to the nitrogen-based emulsifier solution and stirred, and the pH is adjusted to obtain ceramic-based composite nitrogen element emulsified vesicles after a secondary pre-reaction; after adding a surfactant, graphite is added to obtain a nitride ceramic microsphere precursor solution; the mass ratio of graphite to the ceramic substrate component is 14:3.

[0056] The mass ratio of water, emulsifier and nitrogen-containing compound is 72:0.32:20; the emulsifier includes octoxynol and polyoxyethylene polyoxypropylene ether block copolymer;

[0057] In the process of preparing the nitrogen-based emulsifier solution: water is heated to 45°C, then the emulsifier is added, stirred at a speed of 1300r / min for 18 minutes to form emulsified vesicles with stable hollow spherical structures, nitrogen-containing compounds are added and continued to be stirred, and then the pH is adjusted to 8.8; the nitrogen-containing compounds are urea and dimethylaminonitrogen.

[0058] In a negative pressure environment with a pressure of -0.085MP, during the preparation of a nitride ceramic microsphere precursor solution, a ceramic substrate component is added to the nitrogen-based emulsifier solution, and the solution is stirred at a speed of 1300r / min to form nitrogen-based emulsified vesicles, and the pH is adjusted to 6.8; after a secondary pre-reaction, ceramic-based composite nitrogen element emulsified vesicles are obtained; the surfactant includes hexadecyltrimethylammonium bromide and octadecyltrimethylammonium bromide; and the condensate temperature in the condensation device is 6°C.

[0059] The ceramic substrate components include metal nitrates and metal sulfates; specifically aluminum nitrate (aluminum nitrate nonahydrate) and calcium sulfate;

[0060] The mass ratio of the ceramic substrate component to water is 14:60; the surfactant accounts for 0.1% of the mass of the ceramic substrate component.

[0061] In another aspect of the present embodiment, a nitride ceramic microsphere is provided. After washing the nitride ceramic microsphere precursor, the nitride ceramic microsphere is calcined in an inert gas atmosphere to obtain the nitride ceramic microsphere; the calcination temperature is 1350°C.

[0062] The nitride ceramic microspheres can withstand high temperatures of more than 1975°C during use. The particle size of the nitride ceramic microspheres is 0.07 μm, the wall thickness of the nitride ceramic microspheres is 20 nm, and the bulk density of the nitride ceramic microspheres is 0.38 g / cm 3 ; The crushing strength of nitride ceramic microspheres that account for 5% by volume is 72MPa.

[0063] Embodiment 3:

[0064] The same contents as those in Example 1 are not described in detail here. The differences between this embodiment and Example 1 are as follows:

[0065] In one aspect of this embodiment, a method for preparing a nitride ceramic microsphere precursor is provided.

[0066] The mass ratio of water, emulsifier and nitrogen-containing compound is 70:0.35:28; the emulsifier includes octoxynol, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer and polyoxyethylene polyoxypropylene ether block copolymer;

[0067] In the process of preparing the nitrogen-based emulsifier solution: water is heated to 72°C, then the emulsifier is added, and the mixture is stirred at a speed of 1420 r / min for 15 minutes to form emulsified vesicles with stable hollow spherical structures, nitrogen-containing compounds are added and continued to be stirred, and then the pH is adjusted to 8.2; the nitrogen-containing compounds are dimethylaminonitrogen and ethylenediamine.

[0068] Under the condition that the pressure of the negative pressure environment is -0.035MPa, during the preparation of the nitride ceramic microsphere precursor solution, the ceramic substrate component is added to the nitrogen-based emulsifier solution, and the solution is stirred at a speed of 1420r / min to form nitrogen-based emulsified vesicles, and the pH is adjusted to 7.2; after a secondary pre-reaction, ceramic-based composite nitrogen element emulsified vesicles are obtained; the surfactant includes octadecyltrimethylammonium bromide and sodium dodecylbenzenesulfonate; the condensate temperature in the condensation device is 8.5°C.

[0069] The ceramic substrate components include nitrates and metal sulfates; specifically calcium nitrate and aluminum sulfate;

[0070] The mass ratio of the ceramic substrate component to water is 12:72; the surfactant accounts for 0.06% of the mass of the ceramic substrate component.

[0071] In another aspect of the present embodiment, a nitride ceramic microsphere is provided. After washing the nitride ceramic microsphere precursor, the nitride ceramic microsphere is calcined in an inert gas atmosphere to obtain the nitride ceramic microsphere; the calcination temperature is 1450° C.;

[0072] The nitride ceramic microspheres can withstand high temperatures of more than 1985°C during use; the particle size of the nitride ceramic microspheres is 0.05 μm, the wall thickness of the nitride ceramic microspheres is 16 nm, and the bulk density of the nitride ceramic microspheres is 0.30 g / cm 3 ; The crushing strength of nitride ceramic microspheres that account for 5% by volume is 60MPa.

[0073] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features have similar functions to those disclosed in the present application (but not limited to).

Claims

1. A method for preparing a nitride ceramic microsphere precursor, characterized in that: The following steps are involved: A nitrogen-based emulsifier solution is prepared from raw materials including water, an emulsifier and a nitrogen-containing compound, wherein the mass ratio of water, the emulsifier and the nitrogen-containing compound is (55-75): (0.3-0.45): (15-30); Adding ceramic substrate components to the nitrogen-based emulsifier solution and mixing them to prepare a nitride ceramic microsphere precursor solution; the ceramic substrate components include one or more of metal chlorides, metal nitrates, and metal sulfates; The powder in the nitride ceramic microsphere precursor solution is separated from the solvent to obtain the nitride ceramic microsphere precursor.

2. The method for preparing a nitride ceramic microsphere precursor according to claim 1, characterized in that: The preparation of the nitrogen-based emulsifier solution comprises the following steps: Heat water to 40-75°C, then add emulsifier, stir at a speed of 1250-1450r / min for 12-20min to form emulsified vesicles with stable hollow spherical structure, add nitrogen-containing compounds and continue stirring, then adjust the pH to pH=8-9 to obtain a transparent white emulsified nitrogen-containing emulsified vesicle solution; stop stirring, let stand, and obtain a nitrogen-based emulsifier solution after primary pre-reaction.

3. The method for preparing a nitride ceramic microsphere precursor according to claim 2, characterized in that: The preparation of a nitride ceramic microsphere precursor solution comprises the following steps: Under negative pressure, adding ceramic substrate components to the nitrogen-based emulsifier solution, stirring at a speed of 1250-1450 r / min to form nitrogen-based emulsified vesicles, adjusting the pH, obtaining ceramic-based composite nitrogen element emulsified vesicles after secondary pre-reaction, adding a surfactant, and obtaining a nitride ceramic microsphere precursor solution; The pressure of the negative pressure environment is -0.1 MPa to -0.01 MPa.

4. The method for preparing a nitride ceramic microsphere precursor according to claim 3, characterized in that: When preparing the nitride ceramic microsphere precursor solution, the mixing process of the nitrogen-based emulsifier solution and the ceramic substrate component under negative pressure is as follows: Adding the ceramic substrate component to the nitrogen-based emulsifier solution in a mixing device and stirring, evacuating the mixing device through a negative pressure device to achieve a negative pressure state, condensing the gas extracted from the mixing device through a condensing device, and adding the obtained condensate to the mixing device; The temperature of the condensate in the condensation device is 5-10°C.

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

6. The method for preparing a nitride ceramic microsphere precursor according to claim 3, characterized in that: The surfactant includes one or more of hexadecyltrimethylammonium bromide, octadecyltrimethylammonium bromide and sodium dodecylbenzenesulfonate.

7. The method for preparing a nitride ceramic microsphere precursor according to claim 2, characterized in that: The nitrogen-containing compound is one or more of urea, melamine, dimethylaminonitrogen, and ethylenediamine.

8. The method for preparing a nitride ceramic microsphere precursor according to claim 3, characterized in that: When preparing the nitride ceramic microsphere precursor solution, a surfactant is added, and then graphite and / or carbon powder is added to obtain the nitride ceramic microsphere precursor solution.

9. The method for preparing a nitride ceramic microsphere precursor according to claim 3, characterized in that: The mass ratio of the ceramic substrate component to water is (10-15): (55-75); The surfactant accounts for 0.05%-0.25% of the mass of the ceramic substrate component.

10. A nitride ceramic microsphere, characterized in that: The nitride ceramic microspheres are obtained by sintering a nitride ceramic microsphere precursor, and the nitride ceramic microsphere precursor is prepared by the method for preparing a nitride ceramic microsphere precursor according to any one of claims 1 to 9.

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