KR20140118459A - Silicon carbide powder - Google Patents

Abstract

A method for manufacturing a silicon carbide powder according to an embodiment of the present invention comprises the steps of: heat treating a mixture including a silicon carbide powder of beta phase and a carbon source at a first temperature, and obtaining a silicon carbide powder of alpha phase by heat treating the mixture at a second temperature higher than the first temperature.

Description

Silicon Carbide Powder {SILICON CARBIDE POWDER}

The present invention relates to a silicon carbide powder, and more particularly to an alpha-phase silicon carbide powder.

Silicon carbide (SiC) has high high temperature strength, and is excellent in abrasion resistance, oxidation resistance, corrosion resistance and creep resistance. Silicon carbide has a β-phase having a cubic crystal structure and an α-phase having a hexagonal crystal structure. The? phase is stable in the temperature range of 1400-1800 占 폚, and the? phase is formed in 2000 占 폚 or more.

Silicon carbide is widely used as a structural material for industry, and recently it has also been applied to semiconductor devices. For this purpose, the β-phase silicon carbide powder is treated at a high temperature to grow a single crystal. However, the β-phase silicon carbide powder can be phase-transformed to the α-phase silicon carbide powder at the single crystal growth temperature. As a result, the evaporation condensation becomes active, and the height of the growth surface changes, thereby controlling the temperature gradient control.

Therefore, research is being conducted on the technology of using? -Phase silicon carbide powder as a raw material for single crystal growth. The? -phase silicon carbide powder does not cause phase transition even at a high temperature, so that it can stably grow single crystals.

For this purpose, α-phase silicon carbide powders of various particle sizes are required. the growth conditions of the single crystal may vary depending on the particle size of the α-phase silicon carbide powder. However, research on the method of controlling the particle size of the? -Phase silicon carbide powder has been hardly conducted. phase silicon carbide powder can be obtained by treating the silicon carbide powder at a high temperature to obtain an α-phase silicon carbide powder. However, when the treatment time is short, there is a problem that the β phase and the α phase are mixed together. If the treatment time is long, . The α-phase silicon carbide powder having the desired particle size can be recovered through the pouring, but it is difficult to obtain a high-purity powder.

SUMMARY OF THE INVENTION The present invention provides a high purity α-phase silicon carbide powder and a method for producing the same.

The method of manufacturing a silicon carbide powder according to an embodiment of the present invention includes the steps of: heat treating a mixture containing a? -Phase-based silicon carbide powder and a carbon source to a first temperature, and heating the mixture to a second temperature higher than the first temperature Thereby obtaining an? -Phase-based silicon carbide powder.

The particle size of the α-phase silicon carbide powder can be controlled according to the content of the carbon source contained in the mixture.

The carbon source may be included in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the mixture.

The particle size (D ₅₀ ) of the α-phase silicon carbide powder may be 20 μm to 300 μm.

In the step of heat-treating at the first temperature, the carbon source may be decomposed into organic substances and carbon, and then the organic substances may be discharged and the carbon may be left.

The first temperature may be 1300 ° C to 1700 ° C, and the second temperature may be 2000 ° C to 2200 ° C.

The carbon source may be selected from the group consisting of graphite, carbon black, carbon nanotubes (CNT), fullerene, phenol resin, franc resin, xylene resin, And is made of a polyimide resin, a polyurethane resin, a polyvinyl alcohol resin, a polyacrylonitrile resin, a polyvinyl acetate resin, a cellulose, and a mixture thereof Can be selected from the group.

The silicon carbide powder according to an embodiment of the present invention includes an alpha-phase silicon carbide powder having a particle size (D ₅₀ ) of 20 to 300 μm and a scattering (D ₉₀ / D ₁₀ ) of more than 1 and less than 9.

According to the embodiment of the present invention, a high purity α-phase silicon carbide powder can be obtained. Particularly, an α-phase silicon carbide powder having a desired particle size can be obtained. As a result, it is possible to obtain a high-quality single crystal grown at a uniform speed without worrying about the phase transition.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow chart of a method for manufacturing silicon carbide according to one embodiment of the present invention. FIG.
Fig. 2 is a β-phase silicon carbide powder used in Comparative Examples and Examples.
FIG. 3 is an X-ray diffraction (XRD) peak of the β-phase silicon carbide powder in FIG.
4 is a silicon carbide powder according to the result of Comparative Example 1. Fig.
5 is a silicon carbide powder according to the result of Comparative Example 2. Fig.
6 is an XRD peak of the? -Phase-based silicon carbide powder of FIG.
FIGS. 7 to 11 show silicon carbide powders according to the results of Examples 1 to 5, respectively.
12 is an XRD peak of a silicon carbide powder according to the results of Examples 1 to 5. Fig.

The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated and described in the drawings. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms including ordinal, such as second, first, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the second component may be referred to as a first component, and similarly, the first component may also be referred to as a second component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings, wherein like or corresponding elements are denoted by the same reference numerals, and redundant description thereof will be omitted.

In the embodiment of the present invention, the particle size of the? -Phase silicon carbide powder is controlled by mixing a? -Phase-phase silicon carbide powder with a carbon source and then heat-treating it.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow chart of a method for manufacturing silicon carbide according to one embodiment of the present invention. FIG.

Referring to FIG. 1, a β-phase silicon carbide powder is mixed with a carbon source (S100). The carbon source may be a solid carbon source or a liquid resin. The solid carbon source may be selected from the group consisting of, for example, graphite, carbon black, carbon nanotubes (CNT), fullerene, and mixtures thereof. The liquid resin may be, for example, phenol resin, franc resin, xylene resin, polyimide resin, polyurethane resin, polyvinyl alcohol resin, Polyacrylonitrile resins, polyvinyl acetate resins, cellulose, and mixtures thereof. The term " polymer "

Here, the silicon carbide powder and the carbon source on the? -Phase may be wet-mixed. When a liquid resin is used as the carbon source, the silicon carbide powder on the? Phase and the carbon source can be mixed more uniformly.

On the other hand, the carbon source may be included in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the mixture of the silicon carbide powder and the carbon source on the β phase. The particle size of the α-phase silicon carbide powder to be produced can be controlled according to the content of the carbon source contained in the mixture. If the carbon source is contained in an amount less than 0.1 part by weight, the particle size can not be controlled. Can be changed.

Next, a mixture of the silicon carbide powder and the carbon source on? Phase is heat-treated in a chamber (S110). At this time, heat treatment may be performed at a temperature of 1300 ° C to 1700 ° C for a predetermined time. Preferably, it can be heat-treated at 1350 ° C to 1450 ° C for 3 hours. Accordingly, the carbon source contained in the mixture is decomposed into organic matter and carbon. At this time, organic matter is discharged using a vacum pump, so that only carbon can remain in the chamber. When the carbon source is a phenol resin and treated at 1400 ° C for 3 hours, about 50 parts by weight of the phenol resin is discharged into the organic material, and the remaining about 50 parts by weight of the phenol resin may remain in the chamber.

Next, the silicon carbide powder of? Phase and the residual carbon are heat-treated at a temperature higher than the step S110, that is, at a temperature at which the phase shifts from the? -Phase-phase silicon carbide powder to the? -Phase silicon carbide powder for a predetermined time to obtain? ). At this time, heat treatment may be performed at 2200 ° C to 2200 ° C for 4 hours or more. The chamber may be filled with an inert gas (e.g., Ar). After proceeding to step S110, the temperature may be gradually raised to the level of 2200 to 2200 DEG C in the same chamber, or may be transferred to another chamber previously set to 2000 to 2200 DEG C, and then step S120 may be performed.

Here, the residual carbon serves to retard the phase transition from the? -Phase-phase silicon carbide powder to the? -Phase silicon carbide powder. That is, during the phase transition of the β-phase silicon carbide powder to the α-phase silicon carbide powder, there exists a region where the β-phase silicon carbide powder and the α-phase silicon carbide powder are mixed. In order to obtain only the silicon carbide powder on? phase, the heat treatment should be maintained for a predetermined time (for example, 4 hours). However, when the β-phase silicon carbide powder is maintained at a high temperature for 4 hours or more, an excess granular silicon carbide powder can be obtained.

The heat treatment of the silicon carbide powder and the residual carbon together with the β-phase powder reduces the vapor pressure of the carbon, thereby preventing the evaporation condensation mechanism, which is the phase transition mechanism of the silicon carbide powder, and preventing the rapid grain growth of the α-phase silicon carbide powder. Accordingly, the particle size of the α-phase silicon carbide powder may vary depending on the amount of the residual carbon, that is, the amount of the carbon source. For example, the larger the amount of carbon source added, the smaller the particle size of the α-phase silicon carbide powder. Therefore, it is possible to control the amount of the carbon source added depending on the desired particle size.

As described above, the α-phase silicon carbide powder having the desired particle size can be obtained by mixing and heating the β-phase silicon carbide powder with the carbon source and adjusting the amount of the carbon source.

Particularly, when a liquid resin is used as the carbon source, the? -Phase-based silicon carbide powder and the resin are uniformly mixed to obtain an α-phase silicon carbide powder having a uniform particle size, ie, a low dispersion (D ₉₀ / D ₁₀ ).

Hereinafter, the method for producing silicon carbide powder according to the present invention will be described in detail with reference to comparative examples and examples.

≪ Comparative Example 1 &

5N of β-phase silicon carbide powder having an average particle size of 1.7 μm was put into a chamber, heated to 1450 ° C. in a vacuum atmosphere, raised to 2150 ° C. in an argon atmosphere, maintained for 3 hours and cooled naturally.

≪ Comparative Example 2 &

5N of β-phase silicon carbide powder having an average particle size of 1.7 μm was put in a chamber, heated to 1450 ° C. in a vacuum atmosphere, raised to 2150 ° C. in an argon atmosphere, held for 5 hours and cooled naturally.

≪ Example 1 >

5N of β-phase silicon carbide powder having an average particle size of 1.7 μm and 2 parts by weight of phenol resin as a whole were put in a chamber and heated up to 1450 ° C. in a vacuum atmosphere. The temperature was raised to 2150 ° C. in an argon atmosphere, Naturally cooled.

≪ Example 2 >

5N of β-phase silicon carbide powder having an average particle size of 1.7 μm and 4 parts by weight of phenol resin as a whole were put in a chamber and heated up to 1450 ° C. in a vacuum atmosphere. The temperature was raised to 2150 ° C. in an argon atmosphere, Naturally cooled.

≪ Example 3 >

5N of β-phase silicon carbide powder having an average particle size of 1.7 μm and 6 parts by weight of phenol resin were put into a chamber and heated up to 1450 ° C. in a vacuum atmosphere. The temperature was raised to 2150 ° C. in an argon atmosphere and maintained for 5 hours. Naturally cooled.

<Example 4>

5N of β-phase silicon carbide powder having an average particle size of 1.7 μm and 10 parts by weight of phenol resin as a whole were placed in a chamber and heated up to 1450 ° C. in a vacuum atmosphere. The temperature was raised to 2150 ° C. in an argon atmosphere, Naturally cooled.

&Lt; Example 5 >

5N of β-phase silicon carbide powder having an average particle size of 1.7 μm and 12 parts by weight of phenol resin were placed in a chamber and heated up to 1450 ° C. in a vacuum atmosphere. The temperature was raised to 2150 ° C. in an argon atmosphere, Naturally cooled.

FIG. 2 is a β-phase silicon carbide powder used in Comparative Examples and Examples, and FIG. 3 is an X-ray diffraction (XRD) peak of a β-phase silicon carbide powder in FIG. And the vertical axis indicates the intensity at which the light is diffracted. Thus, the crystal phase can be analyzed based on the intensity of light diffracted at a specific angle.

FIG. 4 is a silicon carbide powder according to the result of Comparative Example 1, FIG. 5 is a silicon carbide powder according to a result of Comparative Example 2, and FIG. 6 is an XRD peak of an α phase silicon carbide powder of FIG. In FIG. 6, the abscissa indicates the angle of the light source, and the ordinate indicates the intensity that the light is diffracted and detected.

Referring to FIG. 4, it can be seen that when the β-phase silicon carbide powder is not heated for a sufficient time, a silicon carbide powder in which β phase and α phase are mixed is obtained.

Referring to FIGS. 5 and 6, when the β-phase silicon carbide powder is heated for a sufficient time, it is possible to obtain a high-purity α-phase silicon carbide powder, but it can be seen that an excessive granule is formed.

Figs. 7 to 11 show silicon carbide powders according to the results of Examples 1 to 5, Fig. 12 shows XRD peaks of the silicon carbide powder according to the results of Examples 1 to 5, The particle size and dispersion of the silicon carbide powder according to the results of Examples 1 to 5 are shown.

7 to 12, it can be seen that the particle size of the α-phase silicon carbide powder to be produced decreases with an increase in the amount of carbon source added. In particular, it can be seen that a high-purity α-phase silicon carbide powder can be obtained even if the particle size is as small as several tens of μm.

Table 1 shows the particle size and dispersion of the alpha phase silicon carbide powder to the content of the carbon source added.

Content of carbon source (wt%) Particle size (D ₅₀ , μm) Scatter (D ₉₀ / D ₁₀ ) 2 268 6.71 6 155 8.4 12 64 5.28

As shown in Table 1, according to the embodiment of the present invention, the content of the carbon source is controlled so that the particle size is 20 to 300 占 퐉, preferably 60 to 270 占 퐉, the scattering amount is 1 to 10, it is understood that an α-phase silicon carbide powder can be obtained.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

Claims (1)

A silicon carbide powder comprising an alpha-phase silicon carbide powder having a particle size (D ₅₀ ) of 20 to 300 μm and a scattering (D ₉₀ / D ₁₀ ) of more than 1 and less than 9.

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