阅读说明：本技术 一种高纯碳化硅粉制备方法 (Preparation method of high-purity silicon carbide powder ) 是由 不公告发明人 于 2020-06-29 设计创作，主要内容包括：本发明涉及一种高纯碳化硅粉制备方法,属于碳化硅粉制备方法技术领域。为解决现有制备方法所得碳化硅粉纯度低的问题,本发明提供了一种高纯碳化硅粉制备方法,以晶体硅为硅源制备硅微粉,以葡萄糖为碳源制备葡萄糖溶液,将硅微粉与葡萄糖溶液混合均匀,经干燥、碳化、真空烧结、灼烧和酸洗除杂得到高纯碳化硅粉。本发明制备过程中葡萄糖溶液与硅微粉混合球磨过程中,碳源和硅源反应较为充分,提高了原料利用率；由于所用硅源晶体硅和碳源葡萄糖本身纯度较高,制备过程中引入杂质少,且本发明能将硼、铝、钛、铁、钒等杂质元素有效去除,因此本发明所制备的碳化硅粉纯度可达99.999％。(The invention relates to a preparation method of high-purity silicon carbide powder, belonging to the technical field of preparation methods of silicon carbide powder. The invention provides a preparation method of high-purity silicon carbide powder, aiming at solving the problem of low purity of the silicon carbide powder obtained by the existing preparation method. In the preparation process, in the mixing and ball-milling process of the glucose solution and the silicon micropowder, the carbon source and the silicon source react more fully, so that the utilization rate of the raw materials is improved; because the silicon source crystalline silicon and the carbon source glucose have high purity, less impurities are introduced in the preparation process, and the silicon carbide powder prepared by the method can effectively remove impurity elements such as boron, aluminum, titanium, iron, vanadium and the like, the purity of the silicon carbide powder can reach 99.999 percent.)

1. The preparation method of the high-purity silicon carbide powder is characterized by comprising the following steps:

step one, taking crystalline silicon for crushing and ball-milling to obtain silicon micro powder, taking glucose for dissolving in ultrapure water, adding the silicon micro powder into the obtained glucose solution according to a certain mass ratio of the silicon micro powder to the glucose, and placing the obtained mixed system in a planetary ball mill for uniformly mixing at a certain rotating speed;

step two, drying the mixed system obtained in the step one at a certain temperature, putting the dried sample in an anaerobic condition, and cracking glucose into simple substance carbon at a certain carbonization temperature to obtain a precursor;

thirdly, placing the precursor obtained in the second step at a certain temperature for vacuum sintering to obtain silicon carbide, then placing the obtained silicon carbide sample at a certain temperature for burning treatment to remove unreacted C, and oxidizing the unreacted Si into SiO₂；

And step four, cooling the silicon carbide sample obtained in the step three, washing the silicon carbide sample by using hydrofluoric acid to remove impurities, washing the silicon carbide sample by using ultrapure water, filtering and drying to obtain the high-purity silicon carbide powder.

2. The method for preparing high-purity silicon carbide powder according to claim 1, wherein the particle size of the silicon micropowder in the step one is less than 38 μm.

3. The preparation method of high-purity silicon carbide powder according to claim 1 or 2, wherein the mass ratio of the silicon micropowder to the glucose in the step one is 7: 8-16.

4. The preparation method of high-purity silicon carbide powder according to claim 3, wherein the rotation speed of the planetary ball mill in the first step is 120-240 r/min, and the ball milling time is not less than 2 h.

5. The method for preparing high-purity silicon carbide powder according to claim 4, wherein the drying temperature in the second step is 100-120 ℃, and the drying time is not less than 12 hours.

6. The method for preparing high-purity silicon carbide powder according to claim 5, wherein the anaerobic condition in the second step is a nitrogen or argon atmosphere, the carbonization temperature is 550-850 ℃, and the carbonization time is 2-5 hours.

7. The preparation method of high-purity silicon carbide powder according to claim 6, wherein the vacuum sintering temperature in the third step is 1200-1500 ℃, and the vacuum sintering time is not less than 1 h.

8. The method for preparing high-purity silicon carbide powder according to claim 7, wherein the firing temperature in the third step is 650-800 ℃, and the firing time is 2 hours.

9. The method for preparing high-purity silicon carbide powder according to claim 8, wherein the powder particle size of the high-purity silicon carbide powder obtained in the fourth step is 0.5-2.5 μm.

10. The method for preparing high-purity silicon carbide powder according to claim 9, wherein the purity of the high-purity silicon carbide powder obtained in the fourth step is 99.999%.

Technical Field

The invention belongs to the technical field of a preparation method of silicon carbide powder, and particularly relates to a preparation method of high-purity silicon carbide powder.

Background

Silicon carbide (SiC) is an important synthetic material, and its single crystal is used as a semiconductor substrate material, and its polycrystalline state is widely used as a structural material, and is generally prepared by using silicon carbide powder as a raw material. Industrially, the silicon carbide powder is generally prepared by taking high-purity quartz sand, coke, sodium chloride, wood chips and the like as raw materials through direct high-temperature reaction, and then the procedures of manual selection, crushing, magnetic separation, screening and the like are needed, so that the process is complicated and the process conditions are harsh. Moreover, the process requires treatment temperatures as high as 2200-.

Disclosure of Invention

The invention provides a preparation method of high-purity silicon carbide powder, aiming at solving the problem of low purity of the silicon carbide powder obtained by the existing preparation method.

The technical scheme of the invention is as follows:

a preparation method of high-purity silicon carbide powder comprises the following steps:

step one, taking crystalline silicon for crushing and ball-milling to obtain silicon micro powder, taking high-purity glucose for dissolving in ultrapure water, adding the silicon micro powder into the obtained glucose solution according to a certain mass ratio of the silicon micro powder to the glucose, and placing the obtained mixed system in a planetary ball mill for uniformly mixing at a certain rotating speed;

step two, drying the mixed system obtained in the step one at a certain temperature, putting the dried sample in an anaerobic condition, and cracking glucose into simple substance carbon at a certain carbonization temperature to obtain a precursor;

thirdly, placing the precursor obtained in the second step at a certain temperature for vacuum sintering to obtain silicon carbide, then placing the obtained silicon carbide sample at a certain temperature for burning treatment to remove unreacted C, and oxidizing the unreacted Si into SiO₂；

And step four, cooling the silicon carbide sample obtained in the step three, washing the silicon carbide sample by using hydrofluoric acid to remove impurities, washing the silicon carbide sample by using ultrapure water, filtering and drying to obtain the high-purity silicon carbide powder.

Further, the particle size of the silicon micropowder in the step one is less than 38 microns.

Further, the mass ratio of the silicon micropowder to the glucose in the step one is 8-16: 7.

Further, the rotating speed of the planetary ball mill in the step one is 120-240 r/min, and the ball milling time is not less than 2 h.

Further, in the second step, the drying temperature is 100-120 ℃, and the drying time is not less than 12 hours.

Further, in the second step, the anaerobic condition is a nitrogen or argon atmosphere, the carbonization temperature is 550-850 ℃, and the carbonization time is 2-5 hours.

And further, in the third step, the vacuum sintering temperature is 1200-1500 ℃, and the vacuum sintering time is not less than 1 h.

Further, in the third step, the ignition temperature is 650-800 ℃, and the ignition time is 2 hours.

And furthermore, the powder particle size of the high-purity silicon carbide powder obtained in the fourth step is 0.5-2.5 microns.

Further, the purity of the high-purity silicon carbide powder obtained in the fourth step is 99.999%.

The invention has the beneficial effects that:

the preparation method of the high-purity silicon carbide powder provided by the invention utilizes crystalline silicon as a silicon source, the purity of the crystalline silicon can reach more than 6N generally, the purity of electronic grade crystalline silicon can reach more than 9N, and the crystalline silicon is used as a carbon source and is compared with quartz Sand (SiO)₂) Less impurities are introduced. According to the invention, glucose is selected as a carbon source, and in the process of mixing and ball-milling the glucose solution and the silicon micropowder, the carbon source and the silicon source react sufficiently, so that the utilization rate of the raw materials is improved, the glucose has the advantage of high purity, few introduced impurities are generated, and the purity of the prepared silicon carbide powder is higher. Through detection, the preparation method provided by the invention can effectively remove impurity elements such as boron, aluminum, titanium, iron, vanadium and the like, and finally the purity of the silicon carbide powder reaches 5-6N, namely 99.999%.

The preparation method of the high-purity silicon carbide powder provided by the invention has the advantages of simple process, greatly reduced treatment temperature compared with the traditional method, energy consumption saving, low cost and easy obtainment of the used raw materials. The method has higher economic value and is suitable for the industrial production of the high-purity silicon carbide powder.

Detailed Description

The technical solutions of the present invention are further described below with reference to the following examples, but the present invention is not limited thereto, and any modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention. The process equipment or apparatus not specifically mentioned in the following examples are conventional in the art, and if not specifically mentioned, the raw materials and the like used in the examples of the present invention are commercially available; unless otherwise specified, the technical means used in the examples of the present invention are conventional means well known to those skilled in the art.