阅读说明：本技术 一种利用粉石英加工碳化硅重结晶烧结高纯陶瓷磨料的方法 (Method for processing silicon carbide recrystallization sintering high-purity ceramic abrasive by using powdered quartz ) 是由 朱忠铜 李若普 李业平 廖述斌 于 2019-12-06 设计创作，主要内容包括：本发明公开了一种利用粉石英加工碳化硅重结晶烧结高纯陶瓷磨料的方法,将粉石英、石墨粉按重量比1:0.7混合均匀,通过焙烧炉中进行加热至1700-1800℃,保温进行碳化生成立方碳化硅粉体；然后将步骤一的碳化硅粉体和未反应的粉石英及石墨粉混合物再次进行搅拌混合,混合均匀后,再放入石墨化炉中进行加热,加热至2900-3000℃,保温进行重结晶烧结生成碳化硅颗粒；然后清洗、干燥、破碎并分级得到碳化硅磨料。本发明利用粉石英与石墨混合进行碳化来合成碳化硅粉体,然后再通过对碳化硅粉体与粉石英及石墨粉混合再进行重结晶烧结,制作成高纯碳化硅陶瓷磨料,可以极大的提高碳化硅陶瓷磨料的硬度和强度。(The invention discloses a method for processing silicon carbide recrystallization sintering high-purity ceramic abrasive by using powdered quartz, which comprises the steps of uniformly mixing the powdered quartz and graphite powder according to the weight ratio of 1:0.7, heating the mixture to 1800 ℃ in a roasting furnace, preserving heat and carbonizing the mixture to generate cubic silicon carbide powder; then stirring and mixing the silicon carbide powder obtained in the step one with the unreacted powder quartz and graphite powder mixture again, uniformly mixing, then putting the mixture into a graphitization furnace for heating to 2900-3000 ℃, preserving heat and carrying out recrystallization sintering to generate silicon carbide particles; and then cleaning, drying, crushing and grading to obtain the silicon carbide abrasive. According to the invention, the silicon carbide powder is synthesized by mixing and carbonizing the powdered quartz and the graphite, and then the silicon carbide powder, the powdered quartz and the graphite powder are mixed and recrystallized and sintered to prepare the high-purity silicon carbide ceramic abrasive, so that the hardness and the strength of the silicon carbide ceramic abrasive can be greatly improved.)

1. A method for processing silicon carbide recrystallization sintering high-purity ceramic abrasive by using powdered quartz is characterized by comprising the following steps:

the method comprises the following steps: uniformly mixing quartz powder and graphite powder according to the weight ratio of 1:0.7, heating to 1700-1800 ℃ in a roasting furnace, preserving heat and carbonizing to generate cubic silicon carbide powder;

step two: then stirring and mixing the silicon carbide powder obtained in the step one with the unreacted powder quartz and graphite powder mixture again, uniformly mixing, then putting the mixture into a graphitization furnace for heating to 2900-3000 ℃, preserving heat and carrying out recrystallization sintering to generate silicon carbide particles;

step three: screening and separating the silicon carbide particles, unreacted quartz powder and graphite powder in the step two, and collecting large-particle silicon carbide particles;

step four: washing the large-particle silicon carbide particles collected in the third step with water to remove attachments on the surfaces, and then drying the washed silicon carbide particles;

step five: crushing the silicon carbide particles obtained in the fourth step by using a ball mill, screening and grading, and collecting to prepare silicon carbide abrasive particles;

step six: crushing and grading the silicon carbide micro powder left after screening in the fifth step by using an airflow crushing and grading system to prepare the silicon carbide superfine abrasive;

step seven: and C, preparing the silicon carbide micro powder left after screening in the step six or preparing the silicon carbide nano powder by utilizing the screened silicon carbide micro powder and then passing the silicon carbide micro powder through a nano sand mill to prepare the silicon carbide nano abrasive.

2. The method for processing the silicon carbide recrystallization sintered high-purity ceramic abrasive by using the powdered quartz as claimed in claim 1, which is characterized in that: in the first step, the quartz powder and the graphite powder are mechanically stirred and mixed, the stirring speed is not less than 100r/min, and the stirring time is not less than 10 h.

3. The method for processing the silicon carbide recrystallization sintered high-purity ceramic abrasive by using the powdered quartz as claimed in claim 1, which is characterized in that: in the first step, the carbonization time is not less than 10 h.

4. The method for processing the silicon carbide recrystallization sintered high-purity ceramic abrasive by using the powdered quartz as claimed in claim 1, which is characterized in that: and in the second step, mechanically stirring and mixing the quartz powder and the graphite powder, wherein the stirring speed is not less than 100r/min, and the stirring time is not less than 10 h.

5. The method for processing the silicon carbide recrystallization sintered high-purity ceramic abrasive by using the powdered quartz as claimed in claim 1, which is characterized in that: in the second step, the recrystallization time is not less than 72 h.

6. The method for processing the silicon carbide recrystallization sintered high-purity ceramic abrasive by using the powdered quartz as claimed in claim 1, which is characterized in that: in the sixth step, the silicon carbide micro powder refers to silicon carbide particles with the particle size of less than 40 microns.

7. The method for processing the silicon carbide recrystallization sintered high-purity ceramic abrasive by using the powdered quartz as claimed in claim 1, which is characterized in that: in the sixth step, the granularity of the silicon carbide superfine abrasive is 40-0.5 microns.

8. The method for processing the silicon carbide recrystallization sintered high-purity ceramic abrasive by using the powdered quartz as claimed in claim 1, which is characterized in that: and step seven, preparing the rest silicon carbide micro powder with the grain size less than 0.5 micron after screening in the step six, or preparing silicon carbide nano powder with the grain size of 5-0.5 micron by utilizing the screened silicon carbide micro powder, and preparing the silicon carbide nano abrasive with the grain size of 50-20 nanometers by a nano sand mill.

Technical Field

The invention belongs to the technical field of silicon carbide abrasive materials, and particularly relates to a method for processing silicon carbide, recrystallizing and sintering a high-purity ceramic abrasive material by using powdered quartz.

Background

The cubic silicon carbide has high chemical stability, high hardness, high thermal conductivity, low thermal expansion coefficient, wide energy band gap, high electron drift velocity, high electron mobility, special resistance temperature characteristics and the like, so the cubic silicon carbide has excellent performances of wear resistance, high temperature resistance, thermal shock resistance, corrosion resistance, radiation resistance, good semi-conductive characteristics and the like, and is widely applied to the fields of electrons, information, precision processing technology, war industry, aerospace, high-grade refractory materials, special ceramic materials, high-grade grinding materials, reinforcing materials and the like.

In the production of silicon carbide abrasive, quartz sand or vein quartz and petroleum coke are generally used as raw materials, and are smelted in a smelting furnace at the high temperature of 2000-2500 ℃ to form a silicon carbide block, and the silicon carbide block is required to be acid-washed and purified, and then is crushed, ball-milled and graded to form the abrasive with required granularity. However, in the production mode, the purity of the quartz sand or vein quartz and petroleum coke seriously affects the quality of the silicon carbide, and in consideration of the cost problem, the quartz sand or vein quartz and petroleum coke are difficult to purify in advance, so that the strength and hardness of the produced silicon carbide abrasive are unstable, the microhardness of the silicon carbide generally fluctuates between 2800 and 3300, the microhardness fluctuation under the same process conditions is large, and the ball-milling toughness of the silicon carbide generally ranges from 50 to 60 percent; and the pickling purification process is not friendly to the environment and is more and more restricted and influenced by the environmental policy.

According to the invention, the powder quartz is used as a raw material for carbonization, because the natural powder quartz has high SiO2 content and less impurities, and the purity of the silicon carbide generated by carbonization is high, the requirement of generating the grinding material can be met without an acid washing link; and the silicon carbide abrasive produced by the method has comprehensive performance superior to that of silicon carbide abrasives produced by other methods. The invention provides a method for producing high-performance abrasive materials in a large scale with environmental protection and low cost.

Disclosure of Invention

In order to improve the strength and hardness of the silicon carbide abrasive, the invention provides a method for processing silicon carbide recrystallization sintering high-purity ceramic abrasive by using powdered quartz, wherein the powdered quartz and graphite powder are used as raw materials, and the silicon carbide recrystallization sintering high-purity ceramic abrasive with high hardness and high strength is obtained by adopting a recrystallization process.

In order to achieve the purpose, the invention adopts the following technical scheme. A method for processing silicon carbide recrystallization sintering high-purity ceramic abrasive by using powdered quartz comprises the following steps:

the method comprises the following steps: uniformly mixing quartz powder and graphite powder according to the weight ratio of 1:0.7, heating to 1700-1800 ℃ in a roasting furnace, preserving heat and carbonizing to generate cubic silicon carbide powder;

step two: then stirring and mixing the silicon carbide powder obtained in the step one with the unreacted powder quartz and graphite powder mixture again, uniformly mixing, then putting the mixture into a graphitization furnace for heating to 2900-3000 ℃, preserving heat and carrying out recrystallization sintering to generate silicon carbide particles;

step three: screening and separating the silicon carbide particles, unreacted quartz powder and graphite powder in the step two, and collecting large-particle silicon carbide particles;

step four: washing the large-particle silicon carbide particles collected in the third step with water to remove attachments on the surfaces, and then drying the washed silicon carbide particles;

step five: crushing the silicon carbide particles obtained in the fourth step by using a ball mill, screening and grading, and collecting to prepare silicon carbide abrasive particles;

step six: crushing and grading the silicon carbide micro powder left after screening in the fifth step by using an airflow crushing and grading system to prepare the silicon carbide superfine abrasive;

step seven: and C, preparing the silicon carbide micro powder left after screening in the step six or preparing the silicon carbide nano powder by utilizing the screened silicon carbide micro powder and then passing the silicon carbide micro powder through a nano sand mill to prepare the silicon carbide nano abrasive.

Further preferably, in the step one, the quartz powder and the graphite powder are mechanically stirred and mixed, the stirring speed is not less than 100r/min, and the stirring time is not less than 10 hours.

Further preferably, in the first step, the carbonization time is not less than 10 h.

Further preferably, in the second step, the quartz powder and the graphite powder are mechanically stirred and mixed, the stirring speed is not less than 100r/min, and the stirring time is not less than 10 h.

Further preferably, in the second step, the recrystallization time is not less than 72 h.

Further preferably, in the sixth step, the silicon carbide fine powder refers to silicon carbide particles with a particle size of less than 40 microns.

Further preferably, in the sixth step, the particle size of the silicon carbide superfine abrasive is 40-0.5 microns.

Further preferably, in step seven: and C, preparing the silicon carbide micro powder with the particle size of less than 0.5 micrometer, which is left after the sieving in the sixth step, or preparing silicon carbide nano powder with the particle size of 5-0.5 micrometer by using the sieved silicon carbide micro powder and then using a nano sand mill to prepare the silicon carbide nano abrasive with the particle size of 50-20 nanometers.

The invention has the technical effects that: the powder quartz ore has the structural characteristics of microcrystal and ball-like structure, and has the characteristics of super hardness, strength and the like after carbonization, the invention utilizes the mixing of the powder quartz and graphite to carry out carbonization to synthesize the silicon carbide powder, and then the silicon carbide powder, the powder quartz and the graphite powder are mixed and then are recrystallized and sintered to prepare the high-purity silicon carbide ceramic abrasive, so that the hardness and the strength of the silicon carbide ceramic abrasive can be greatly improved, and the obtained silicon carbide has the microhardness of 3100 and 3200 and stable quality. The ball milling toughness of the silicon carbide obtained by the invention reaches 70%, and the ball milling toughness detection data of the silicon carbide obtained by the invention is the highest in common ceramic (including alumina, silicon carbide and the like) grinding materials (the ball milling toughness of the common silicon carbide is about 50-60%, and the ball milling toughness of the grinding material with the highest ball milling toughness in the current market is 68%).

Drawings

FIG. 1 is a scanning electron micrograph of silicon carbide particles obtained in example 1.

Fig. 2 is an energy spectrum of the identified location in fig. 1.

FIG. 3 is a scanning electron micrograph of the abrasive obtained in example 1.

Detailed Description

For the sake of understanding, the present invention will be explained in further detail below with reference to the drawings and examples.

A method for processing silicon carbide recrystallization sintering high-purity ceramic abrasive by using powdered quartz comprises the following steps:

the method comprises the following steps: mixing quartz powder and graphite powder according to a weight ratio of 1:0.7, mechanically stirring and mixing uniformly (stirring speed is not less than 100r/min, stirring time is not less than 10h), heating in a roasting furnace (heating to 1700 plus materials 1800 ℃, heat preservation is not less than 10h), and carbonizing to generate cubic silicon carbide powder;

step two: then stirring and mixing the silicon carbide powder obtained in the step one with the unreacted powder quartz and graphite powder mixture again (the stirring speed is not less than 100r/min, and the stirring time is not less than 10 hours), uniformly mixing, and then putting the mixture into a graphitization furnace for heating (heating to 2900-;

step three: screening and separating the silicon carbide particles, unreacted quartz powder and graphite powder in the step two, and collecting large-particle silicon carbide particles;

step four: washing the large-particle silicon carbide particles collected in the third step with water to remove attachments on the surfaces, and then drying the washed silicon carbide particles;

step five: crushing the silicon carbide particles obtained in the fourth step by using a ball mill, screening and grading, and collecting to prepare silicon carbide abrasive grain materials with the grain size of 2000-40 micrometers;

step six: crushing and grading the remaining silicon carbide micro powder with the particle size of less than 40 micrometers after screening in the fifth step by using an airflow crushing and grading system to prepare the silicon carbide superfine abrasive with the particle size of 40-0.5 micrometers;

step seven: and C, preparing the silicon carbide micro powder with the particle size of less than 0.5 micrometer, which is left after the sieving in the sixth step, or preparing silicon carbide nano powder with the particle size of 5-0.5 micrometer by using the sieved silicon carbide micro powder and then using a nano sand mill to prepare the silicon carbide nano abrasive with the particle size of 50-20 nanometers.