阅读说明：本技术 一种SiC纳米粉体颗粒的制备方法 (Preparation method of SiC nano powder particles ) 是由 王志江 于 2020-07-31 设计创作，主要内容包括：一种SiC纳米粉体颗粒的制备方法,它属于碳化硅制备、陶瓷粉体、纳米材料制备技术领域,它要解决现有碳化硅粉体的制备存在产率低、粒径分布不均匀和纯度较低的问题。方法：一、大分子多糖胶体溶液的制备；二、反应前驱体干凝胶粉体的制备；三、纳米SiC颗粒初产物的制备；四、纳米SiC粉体颗粒的调控制备；五、除杂,即完成SiC纳米粉体颗粒的制备。本发明中根据反应物的比例以及形状调节剂的添加量可以调控生成SiC颗粒的尺寸；本发明制备的SiC纳米粉体颗粒的具有纳米尺度且粒度均匀、纯度高、产率高,可批量工业化生产的优点。本发明应用于SiC纳米粉体颗粒的制备。(A preparation method of SiC nano powder particles belongs to the technical field of silicon carbide preparation, ceramic powder and nano material preparation, and aims to solve the problems of low yield, uneven particle size distribution and low purity of the existing silicon carbide powder preparation. The method comprises the following steps: firstly, preparing a macromolecular polysaccharide colloidal solution; secondly, preparing a reaction precursor xerogel powder; thirdly, preparing a primary product of the nano SiC particles; fourthly, regulating and controlling preparation of nano SiC powder particles; and fifthly, removing impurities to finish the preparation of the SiC nano powder particles. The size of the generated SiC particles can be regulated and controlled according to the proportion of reactants and the addition amount of the shape regulator; the SiC nano powder particles prepared by the method have the advantages of nano scale, uniform granularity, high purity, high yield and batch industrial production. The method is applied to the preparation of SiC nano powder particles.)

1. A preparation method of SiC nano powder particles is characterized by comprising the following steps:

firstly, preparing a macromolecular polysaccharide colloidal solution:

preparing cetyl trimethyl ammonium bromide into a cationic surfactant solution with the concentration of 0.1-1 mol/L by using deionized water or absolute ethyl alcohol, then sequentially adding alkaline substances, ammonia water and anthraquinone under an ultrasonic dispersion condition, standing for 1-3 h to obtain an alkaline dissolving agent, then adding biomass macromolecular polysaccharide, and stirring for 1-5 h at the rotating speed of 3000-8000 r/min to obtain a macromolecular polysaccharide colloidal solution;

secondly, preparing a reaction precursor xerogel powder:

adding tetraethoxysilane and hexamethyldisilane into the macromolecular polysaccharide colloidal solution obtained in the step one to prepare a precursor solution, then uniformly stirring the precursor solution under constant-temperature heating in a water bath at the temperature of 60-90 ℃ to obtain a gel system, standing and drying the gel system to obtain a dry gel block, and grinding the dry gel block into powder to obtain a reaction precursor dry gel powder; the mass ratio of the macromolecular polysaccharide colloidal solution to the total mass of the ethyl orthosilicate and the hexamethyldisilane is 10: 1;

thirdly, preparing a primary product of the nano SiC particles:

placing the dry gel powder of the reaction precursor obtained in the step two in the center of a covered graphite crucible, and carrying out carbonization treatment under the protection of inert gas to obtain a primary product of nano SiC particles;

fourthly, regulating and preparing the nano SiC powder particles:

uniformly mixing the primary nano SiC particle product obtained in the step three with a shape regulator according to the mass ratio of (10-50): 1, then placing the mixture in the center of a covered graphite crucible, and carrying out sintering reaction under the protection of inert gas to complete the regulation and control of nano SiC powder particles;

fifthly, removing impurities: and (4) removing impurities from the nano SiC powder particles regulated and controlled in the fourth step to complete the preparation of the SiC nano powder particles.

2. The method for preparing SiC nano powder particles according to claim 1, wherein in the first step, the mass fraction of the alkaline substance in the alkaline dissolving agent is 1-20 w%, the volume fraction of the ammonia water is 1-10 w%, and the mass fraction of the anthraquinone is 0.05-1 w%.

3. The method of claim 1, wherein the alkaline substance is one or more of LiOH, NaOH, and KOH.

4. The method for preparing SiC nano powder particles according to claim 1, wherein in the first step, the biomass macromolecular polysaccharide is one or a combination of more of plant cellulose, bacterial cellulose, lignin and gelatin.

5. The method for preparing SiC nano powder particles according to claim 1, wherein the addition amount of the biomass macromolecular polysaccharide in the first step is 5-30 w% of the mass of the alkaline dissolving agent.

6. The method for preparing SiC nano powder particles according to claim 1, wherein the adding proportion of the tetraethoxysilane and the hexamethyldisilane in the step two is 1ml (1-10) ml; the standing time is 1-2 h; the drying temperature is 100-160 ℃.

7. The method for preparing SiC nano powder particles according to claim 1, wherein the temperature of the carbonization treatment in the third step is 500-800 ℃, the time is 1-6 h, and the temperature rise rate is 1-5 ℃/min.

8. The method according to claim 1, wherein the shape modifier is MgCl₂The purity was analytical grade.

9. The method for preparing SiC nano powder particles according to claim 1, wherein the sintering reaction in the fourth step comprises: and (3) performing high-temperature reaction for 1-4 h at 1400-1700 ℃ in a high-temperature sintering furnace under the protection of argon, and then cooling to room temperature at the heating and cooling rates of 2.5-10 ℃/min.

10. The method for preparing SiC nano powder particles according to claim 1, wherein the impurity removal treatment in the fifth step comprises: soaking the regulated nano SiC powder particles in hydrofluoric acid with the mass fraction of 40% for 2-8 h, taking out the nano SiC powder particles, repeatedly washing the nano SiC powder particles with distilled water to be neutral, soaking the nano SiC powder particles in hydrogen peroxide solution with the mass fraction of 10-30% for 1-4 h, soaking the nano SiC powder particles in the distilled water for 2-6 h, filtering and drying the nano SiC powder particles, placing the nano SiC powder particles in a muffle furnace, heating the nano SiC powder particles to 500-800 ℃ in air, firing the nano SiC powder particles for 1-6 h, washing, filtering and drying the nano SiC powder particles, placing the nano SiC powder particles in an oxygen atmosphere with the vacuum degree of 0.06-0.09 MPa and the purity of 99.9% in a near infrared heat source, and heating the nano SiC powder.

Technical Field

The invention belongs to the technical field of silicon carbide preparation, ceramic powder and nano material preparation, and particularly relates to a preparation method of SiC nano powder particles.

Background

The silicon carbide has the characteristics of large forbidden band width, stable chemical property, strong acid resistance, strong alkali resistance, oxidation resistance, high thermal conductivity, strong thermal stability, high electron saturation mobility, high critical breakdown voltage and the like, and has wide application prospect in the aspects of high-temperature, high-frequency, high-power and anti-irradiation semiconductor devices. The silicon carbide nano powder particle material becomes a research hotspot in the field of materials by the unique physical properties of light, electricity, machinery and the like. The macro-quantitative and large-scale preparation of silicon carbide nanoparticles with uniform nanoscale size is still an important problem in the current industry. Carbothermic reduction using conventional sources of carbon silicon is a commonly used industrial method for the preparation of silicon carbide. Such as carbon black, graphite, silicon dioxide, silicon powder and the like as carbon silicon sources, compared with crystalline solid granular carbon and silicon sources, the sol-state carbon source and the silicon source dispersion system are liquid phases, and the mixing degree is uniform. Because the sol-gel method adopts the compound with high chemical activity component as the precursor to form uniform and stable sol, the preparation of the nano silicon carbide particles is facilitated.

By researching the thermodynamic nucleation and the kinetic growth behavior in the sol-gel method, the growth mechanism for controlling the micro-morphology of the powder is mastered, the bottleneck problem of industrialization of the silicon carbide nano powder is broken through, and the research of the domestic high-end silicon carbide nano powder has important significance.

Disclosure of Invention

The invention aims to solve the problems of low yield, uneven particle size distribution and low purity of the existing preparation of silicon carbide powder, and provides a preparation method of SiC nano powder particles.

A preparation method of SiC nano powder particles is realized according to the following steps:

firstly, preparing a macromolecular polysaccharide colloidal solution:

preparing cetyl trimethyl ammonium bromide into a cationic surfactant solution with the concentration of 0.1-1 mol/L by using deionized water or absolute ethyl alcohol, then sequentially adding alkaline substances, ammonia water and anthraquinone under an ultrasonic dispersion condition, standing for 1-3 h to obtain an alkaline dissolving agent, then adding biomass macromolecular polysaccharide, and stirring for 1-5 h at the rotating speed of 3000-8000 r/min to obtain a macromolecular polysaccharide colloidal solution;

secondly, preparing a reaction precursor xerogel powder:

adding tetraethoxysilane and hexamethyldisilane into the macromolecular polysaccharide colloidal solution obtained in the step one to prepare a precursor solution, then uniformly stirring the precursor solution under constant-temperature heating in a water bath at the temperature of 60-90 ℃ to obtain a gel system, standing and drying the gel system to obtain a dry gel block, and grinding the dry gel block into powder to obtain a reaction precursor dry gel powder; the mass ratio of the macromolecular polysaccharide colloidal solution to the total mass of the ethyl orthosilicate and the hexamethyldisilane is 10: 1;

thirdly, preparing a primary product of the nano SiC particles:

placing the dry gel powder of the reaction precursor obtained in the step two in the center of a covered graphite crucible, and carrying out carbonization treatment under the protection of inert gas to obtain a primary product of nano SiC particles;

fourthly, regulating and preparing the nano SiC powder particles:

uniformly mixing the primary nano SiC particle product obtained in the step three with a shape regulator according to the mass ratio of (10-50): 1, then placing the mixture in the center of a covered graphite crucible, and carrying out sintering reaction under the protection of inert gas to complete the regulation and control of nano SiC powder particles;

fifthly, removing impurities: and (4) removing impurities from the nano SiC powder particles regulated and controlled in the fourth step to complete the preparation of the SiC nano powder particles.

The reaction principle of the invention is as follows: the biomass macromolecular polysaccharide is treated and dissolved by an alkaline solution system to be used as a reaction carbon source, the surface tension of alkaline dissolving liquid is reduced by utilizing a surfactant to promote the permeation effect and accelerate the dissolution of the biomass macromolecules, and the biomass material contains a large amount of active groups which are dissolved and then are beneficial to the interaction and the uniform dispersion with a silicon source in the solution system. Ethyl orthosilicate and hexamethyldisilane are subjected to a series of operations to provide a carbon source and a silicon source in the reaction. In a liquid phase dispersion system by a sol-gel method, the mixing degree of the carbon source and the silicon source is more uniform than that of the solid reaction raw material which is mechanically mixed. In the form of MgCl as a shape regulator₂Under the action, the carbon and silicon sources which are completely mixed at high temperature uniformly enter the interior of molten metal salt ions, the growth process of SiC is effectively controlled to grow along the (111) crystal face with the lowest accumulated energy of the silicon carbide crystals, and the supersaturated linear growth is inhibited in the reaction process, so that the preparation of nano-scale particles is realized; and according to the reactionThe proportion of the compound and the addition amount of the shape regulator can regulate and control the size of the generated SiC particles.

The invention has the beneficial effects that: the prepared SiC nano powder particles have the advantages of nano scale, uniform granularity, high purity, high yield and batch industrial production.

The method is applied to the preparation of SiC nano powder particles.

Drawings

FIG. 1 is an XRD spectrum of SiC nanopowder particles prepared in the examples;

FIG. 2 is a microscopic morphology of SiC nanopowder particles prepared in the examples.

Detailed Description

The technical solution of the present invention is not limited to the following specific embodiments, but includes any combination of the specific embodiments.