阅读说明：本技术 一种基于NaF形状调节剂的纳米碳化硅颗粒的制备方法 (Preparation method of nano silicon carbide particles based on NaF shape regulator ) 是由 王志江 于 2020-06-22 设计创作，主要内容包括：一种基于NaF形状调节剂的纳米碳化硅颗粒的制备方法,它属于碳化硅制备、半导体材料制备技术领域,它要解决现有碳化硅粉体的制备存在成本高、反应温度高、过程不易控制、工艺复杂、产率低、纯度较低和粒径分布不均匀的问题。方法：一、碳前驱体的制备；二、碳前驱体、NaF、纳米硅微粉和乙醇溶液球磨后喷雾干燥,得混合物料；三、混合物料高温烧结炉,得到预产物；四、除杂处理。本发明通过NaF、硅源以及碳源的相互作用,有效抑制碳化硅的过饱和的线状生长,控制粒子形貌与粒径。本发明的制备方法简单,反应温度适中、过程易控制,从而提高了生产效率,并且产品纯度高,粒径分布均匀。本发明应用于纳米级碳化硅颗粒的制备。(A preparation method of nano silicon carbide particles based on a NaF shape regulator belongs to the technical field of silicon carbide preparation and semiconductor material preparation, and aims to solve the problems of high cost, high reaction temperature, difficulty in controlling the process, complex process, low yield, low purity and uneven particle size distribution of the existing silicon carbide powder preparation. The method comprises the following steps: firstly, preparing a carbon precursor; secondly, ball-milling the carbon precursor, NaF, the nano-silicon micro-powder and an ethanol solution, and then spray-drying to obtain a mixed material; thirdly, mixing the materials in a high-temperature sintering furnace to obtain a pre-product; and fourthly, impurity removal treatment. According to the invention, through the interaction of NaF, a silicon source and a carbon source, the supersaturated linear growth of silicon carbide is effectively inhibited, and the morphology and the particle size of particles are controlled. The preparation method is simple, the reaction temperature is moderate, the process is easy to control, the production efficiency is improved, the product purity is high, and the particle size distribution is uniform. The method is applied to the preparation of the nano silicon carbide particles.)

1. A preparation method of nano silicon carbide particles based on a NaF shape regulator is characterized by comprising the following steps:

firstly, preparing a carbon precursor:

placing glucose in a tube furnace, heating to 400-800 ℃ under the protection of nitrogen, and carbonizing for 1-4 hours to obtain a carbon precursor;

secondly, placing the carbon precursor, NaF, nano-silicon micro powder and an ethanol solution with the mass concentration of 20-30% in a ball mill for ball milling, taking out, and performing spray drying to obtain a mixed material;

thirdly, placing the mixed material obtained in the second step into a high-temperature sintering furnace, heating to 1200-1800 ℃ under the protection of nitrogen, reacting for 1-8 h, and then cooling to room temperature to obtain a pre-product;

fourthly, impurity removal treatment:

and (3) soaking the pre-product obtained in the third step in hydrofluoric acid for 10-20 min, taking out, placing in a muffle furnace, heating to 500-800 ℃ in air, igniting for 1-6 h, washing, filtering and drying to complete the preparation of the nano silicon carbide particles based on the NaF shape regulator.

2. The method for preparing nano silicon carbide particles based on NaF shape regulator as claimed in claim 1, wherein the diameter of the glucose in step one is 10-100 nm.

3. The preparation method of nano silicon carbide particles based on NaF shape regulator as claimed in claim 1, wherein in step one, the temperature is raised to 600 ℃ and the nano silicon carbide particles are carbonized for 2 h.

4. The method for preparing nano silicon carbide particles based on NaF shape regulator as claimed in claim 1, wherein the mixture in step two comprises 10-50 parts by mass of carbon precursor, 0.5-10 parts by mass of NaF and the balance of nano silicon powder per 100 parts by mass of the mixture.

5. The method for preparing nano silicon carbide particles based on the NaF shape regulator as claimed in claim 1, wherein the ethanol solution with the mass concentration of 20-30% in the second step accounts for 40-50% of the weight of the mixture.

6. The method for preparing nano silicon carbide particles based on NaF shape regulator according to claim 1, wherein the rotation speed of the ball mill in the second step is 150-300 r/min, the ball milling time is 1-4 h, the ball-to-material ratio is (1-2): 1, and the material of the grinding balls is cemented carbide.

7. The method for preparing nano silicon carbide particles based on NaF shape regulator as claimed in claim 1, wherein the temperature increase in the third step is: heating to 1000 ℃ at the speed of 5-10 ℃/min, and then continuously heating to 1200-1800 ℃ at the speed of 2.5-5 ℃/min.

8. The method for preparing nano silicon carbide particles based on NaF shape regulator as claimed in claim 1, wherein the cooling in step three is: and cooling to 700 ℃ at the speed of 5-10 ℃/min, and then cooling to room temperature along with the furnace.

9. The method for preparing nano silicon carbide particles based on NaF shape regulator as claimed in claim 1, wherein the concentration of hydrofluoric acid in step four is 40-44% by mass.

10. The preparation method of nano silicon carbide particles based on NaF shape regulator as claimed in claim 1, characterized by the steps of washing, filtering and drying: washing with distilled water for 1-3 times, screening with a screen of 10-30 meshes, and drying at 80 ℃ for 20-40 min.

Technical Field

The invention belongs to the technical field of silicon carbide preparation and semiconductor material preparation, and particularly relates to a preparation method of nano silicon carbide particles based on a NaF shape regulator.

Background

The silicon carbide ceramic has the advantages of good mechanical property, oxidation resistance, wear resistance, thermal stability, thermal shock resistance, chemical corrosion resistance, small thermal expansion coefficient, large thermal conductivity and the like. In order to meet the use requirements of some silicon carbide ceramic products with specific structures, such as silicon carbide ceramic membranes and the like, the grain size of raw materials is required to be small enough, and the sphericity is required to be high enough. The preparation of the nano-scale silicon carbide powder is more and more favored, a great deal of intensive research is already carried out on the preparation of SiC powder, but the research on the preparation of the silicon carbide powder with controllable granularity and morphology, especially the preparation of the nano-scale powder with uniform granularity is very lacked, and the preparation technology of the silicon carbide powder has the defects of high cost, high reaction temperature (above 2000 ℃), difficult process control, complex process, low yield, lower purity of synthesized powder, uneven particle size distribution of powder particles, easy agglomeration of the powder particles and the like.

Disclosure of Invention

The invention aims to solve the problems of high cost, high reaction temperature, difficult process control, complex process, low yield, low purity and uneven particle size distribution in the existing preparation of silicon carbide powder, and provides a preparation method of nano silicon carbide particles based on a NaF shape regulator.

A preparation method of nano silicon carbide particles based on a NaF shape regulator is realized by the following steps:

firstly, preparing a carbon precursor:

placing glucose in a tube furnace, heating to 400-800 ℃ under the protection of nitrogen, and carbonizing for 1-4 hours to obtain a carbon precursor;

secondly, placing the carbon precursor, NaF, nano-silicon micro powder and an ethanol solution with the mass concentration of 20-30% in a ball mill for ball milling, taking out, and performing spray drying to obtain a mixed material;

thirdly, placing the mixed material obtained in the second step into a high-temperature sintering furnace, heating to 1200-1800 ℃ under the protection of nitrogen, reacting for 1-8 h, and then cooling to room temperature to obtain a pre-product;

fourthly, impurity removal treatment:

and (3) soaking the pre-product obtained in the third step in hydrofluoric acid for 10-20 min, taking out, placing in a muffle furnace, heating to 500-800 ℃ in air, igniting for 1-6 h, washing, filtering and drying to complete the preparation of the nano silicon carbide particles based on the NaF shape regulator.

The reaction principle of the invention is as follows: under high temperature, a carbon source and a silicon source generate SiO and CO gases to generate silicon carbide, NaF is used as a shape regulator, wherein, the F element has extremely strong electronegativity, free fluoride ions and sodium ions are introduced into the NaF in a molten state to inhibit the growth of silicon carbide particles, a crystal face is modified, and the supersaturation degree of a gaseous intermediate product generated in the molten state is controlled to control the particle appearance and particle size, so that the prepared boron carbide nano particles have uniform and stable size which is far smaller than the particle size of silicon carbide particles prepared without adding the NaF shape regulator.

The invention has the beneficial effects that: by adopting NaF as a shape regulator, the supersaturated linear growth of silicon carbide is effectively inhibited through the interaction between the NaF, a silicon source and a carbon source, and the morphology and the particle size of the particles are controlled. The preparation method is simple, the reaction temperature is moderate, the process is easy to control, the production efficiency is improved, the product purity is high, the particle size distribution is uniform, and the method is suitable for large-scale industrial production.

The method is applied to the preparation of the nano silicon carbide particles.

Drawings

FIG. 1 is an XRD spectrum of nano silicon carbide particles based on NaF shape regulator prepared in the example;

fig. 2 is a micro-topography of nano silicon carbide particles based on NaF shape modifiers 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.