KR102143989B1 - Producing device of boron nitride nano tube - Google Patents

Abstract

The present invention relates to a device for producing boron nitride nanotubes. The device for producing boron nitride nanotubes of the present invention comprises: a reaction body providing a space in which thermal plasma jets and boron nitride nanotubes are formed; at least one plasma unit disposed at one end of the reaction body and generating thermal plasma; a precursor supply unit for supplying a precursor to a space in which the thermal plasma is formed; and a reaction gas supply unit for supplying a reaction gas to the space in which the thermal plasma is formed. The present invention has an effect of inducing a fast reaction rate by intensively applying plasma thermal energy.

Description

Boron nitride nanotube manufacturing apparatus {PRODUCING DEVICE OF BORON NITRIDE NANO TUBE}

The present invention relates to an apparatus for producing boron nitride nanotubes. More specifically, the present invention relates to an apparatus for manufacturing a boron nitride nanotube capable of easy plasma control, a continuous process, and capable of mass synthesis of boron nitride nanotubes.

Boron nitride nanotube (BNNT) is a material that forms a cylindrical tube by connecting three boron atoms and three nitrogen atoms in a single hexagon, and is a structural analogue of carbon nanotubes (CNTs).

BNNT and CNT have similar basic physical properties, but their thermal stability (oxidation resistance) is 800℃, which is more than twice as high as CNT (400℃), and has excellent thermal conductivity (3,000W/mk), and has a wide band gap of 5.5eV. Because it has, it has electrical insulation. Mechanical properties also have a very high level of 1.18TPa similar to CNT (~1.33TPa), so it has excellent applicability as a mechanical property enhancer. In addition, although BNNT is an insulator, since polarity exists, it has piezoelectricity due to the potential difference due to polarity change between the fillers in the composite material, so it can be applied as a piezoelectric material. In particular, the neutron absorption performance of BNNT is CNT (0.0035 Barn), which is about 200,000 times higher than 767 barns, it can be used as an effective radiation shielding agent in various fields including aerospace, defense facilities, space suits, medicine and power plants.

These excellent properties of BNNT are evaluated as a promising material that can be applied to various fields throughout the industry, such as electronic devices, optoelectronic devices, energy storage devices, nanoelectromechanical systems, and biomaterials, and IoT, wearable sensors, robots, and biomaterials. As it can be used industrially, its importance is highly evaluated as a core material that will lead the 4th industrial revolution.

Despite the excellent properties and industrial applicability of BNNT, the level of synthesis technology of BNNT up to now is in a state of fragility at almost no level. Recently, cases of successful BNNT synthesis using various synthesis methods have been reported, but the level of the amount synthesized is very low. There is an urgent need to secure technology for mass synthesis in a very small amount.

Conventional methods for synthesizing BNNT include gaseous reaction methods and chemical leaching methods, but the gaseous reaction method has disadvantages that it is difficult to handle the reaction gas used for gaseous reaction and the production rate is slow. When used, it must undergo a leaching process at a high temperature of 400 to 500K, and when CO(NH ₂ ) ₂ is used, the reaction must be proceeded by reduction of carbon, so it is difficult to precisely control the purity of the powder.

Currently, BNNT is entirely dependent on foreign imports, and the price is sold at a high price of over 700$ per gram. This puts a lot of burden on domestic BNNT application technology research and acts as an important factor limiting the industrial use of BNNT, so it is necessary to develop a production technology that can supply BNNT at a low price.

The present invention has been devised to solve the problems of the prior art as described above, and provides an apparatus for producing boron nitride nanotubes capable of inducing a fast reaction rate by intensively applying plasma thermal energy for the synthesis of high-purity and high-quality BNNTs. It aims to provide.

In addition, it is an object of the present invention to provide an apparatus for manufacturing boron nitride nanotubes that can easily control plasma, enable a continuous process, and enable mass synthesis of boron nitride nanotubes.

However, these problems are exemplary, and the scope of the present invention is not limited thereby.

According to an aspect of the present invention for solving the above problem, there is provided an apparatus for manufacturing a boron nitride nanotube, comprising: a reaction body providing a space in which a thermal plasma jet and a boron nitride nanotube are formed; At least one plasma unit disposed at one end of the reaction body and generating thermal plasma; A precursor supply unit supplying a precursor to a space in which a thermal plasma is formed; And there is provided a boron nitride nanotube manufacturing apparatus comprising a reaction gas supply unit for supplying a reaction gas to the space in which the thermal plasma is formed.

In addition, according to an embodiment of the present invention, the plasma unit may be a DC plasma torch.

In addition, according to an embodiment of the present invention, the precursor includes boron, the reaction gas includes nitrogen, and ammonia or hydrogen may be further supplied to the reaction gas supply unit.

Further, according to an embodiment of the present invention, boron nitride nanotubes may be formed by thermal plasma at a temperature of 3,000K to 6,000K.

In addition, according to an embodiment of the present invention, when a DC plasma torch is used in the plasma unit, argon is not used as a reactive gas, and boron nitride nanotubes are used at a lower temperature than the RF plasma torch. Can be manufactured.

In addition, according to an embodiment of the present invention, a graphite liner part may be installed on the inner wall of the reaction body.

In addition, according to an embodiment of the present invention, the reaction body includes a first path and a second path communicating at an angle to an end of the first path, and a plasma unit is formed in each of the first path and the second path. And the precursor supply unit may be connected to the first path.

In addition, according to an embodiment of the present invention, the reaction body includes a plurality of first paths and a second path communicating at an angle to ends of the plurality of first paths, each of the first path and the second path Plasma units are disposed one by one, and a precursor supply unit may be connected to the first path.

In addition, according to an embodiment of the present invention, the three plasma units are radially disposed at one end of the reaction body at a predetermined distance from each other, and the plasma unit is arranged so that an arbitrary straight line extending from the three plasma units contacts the inner space of the reaction body. It may be arranged to be inclined at a predetermined angle with respect to the horizontal plane.

In addition, according to an embodiment of the present invention, a precursor and a reaction gas may be supplied to a space in which an arbitrary straight line extending from the three plasma units contacts the inner space of the reaction body.

According to the present invention configured as described above, there is an effect of inducing a fast reaction rate by intensively applying plasma thermal energy for the synthesis of high-purity and high-quality BNNTs.

In addition, according to the present invention, there is an effect that plasma control is easy, a continuous process is possible, and mass synthesis of boron nitride nanotubes is possible.

1 is a schematic diagram showing a mechanism for synthesizing boron nitride nanotubes according to an embodiment of the present invention.
2 is a schematic diagram showing an apparatus for manufacturing boron nitride nanotubes according to an embodiment of the present invention.
3 is a schematic diagram showing an apparatus for manufacturing boron nitride nanotubes according to another embodiment of the present invention.
4 is a side cross-sectional and plan schematic view showing an apparatus for manufacturing boron nitride nanotubes according to another embodiment of the present invention.
5 shows a photo of a boron nitride nanotube synthesis and an SEM photo according to an embodiment of the present invention.
6 shows a TEM photograph of the synthesized boron nitride nanotubes according to an embodiment of the present invention.

For a detailed description of the present invention described below, reference is made to the accompanying drawings that illustrate specific embodiments in which the present invention may be practiced. These embodiments are described in detail sufficient to enable a person skilled in the art to practice the present invention. It is to be understood that the various embodiments of the present invention are different from each other but need not be mutually exclusive. For example, specific shapes, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the present invention in relation to one embodiment. In addition, it is to be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the present invention. Accordingly, the detailed description to be described below is not intended to be taken in a limiting sense, and the scope of the present invention, if appropriately described, is limited only by the appended claims, along with all scopes equivalent to those claimed by the claims. In the drawings, similar reference numerals refer to the same or similar functions over several aspects, and the length, area, thickness, and the like may be exaggerated and expressed for convenience.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to enable those of ordinary skill in the art to easily implement the present invention.

1 is a schematic diagram showing a mechanism for synthesizing boron nitride nanotubes according to an embodiment of the present invention.

Referring to FIG. 1, the process of synthesizing the boron nitride nanotubes 20 may be performed by injecting precursors P1 and P2, which are raw material powders, into a space in which a thermal plasma jet P is formed. The precursors (P1, P2) are preferably boron, but BN including boron may be used.

In addition to the precursors P1 and P2, a reaction gas for inducing the efficient synthesis of the boron nitride nanotubes 20 may be added. The reaction gas contains nitrogen, H ₂ , NH ₃ It may contain more. Since the reaction gas induces the formation of NH and converts it to an N radical by decomposing it again, it may be due to the improvement in productivity of the boron nitride nanotube 20 by facilitating bonding with B included in the precursor.

The decomposition temperature of nitrogen is about 4,000 K or higher and recombination at 3,000 K or lower, so it is difficult to exist in a radical state below 3,000 K, making the synthesis of boron nitride nanotubes difficult, whereas in the case of NH, the decomposition temperature is 2,000 K or higher. Through the addition of a compound including hydrogen and a hydrogen atom, it is possible to easily synthesize the boron nitride nanotubes 20 even in the 2,000 ~ 3,000 K section and increase the synthesis efficiency.

It is preferable to use a DC plasma torch as an apparatus for forming the thermal plasma jet P. Since the DC plasma can use nitrogen as a discharge gas, nitrogen radicals for synthesizing the boron nitride nanotubes 20 can be abundantly generated. In the case of using an RF plasma torch, argon (Ar) is used as a discharge gas due to a discharge principle, and a large amount of nitrogen gas cannot be added, so it is difficult to generate abundant nitrogen radicals. In addition, the cost of the RF plasma torch is 10 times higher than that of the DC plasma torch, so the economy is poor

Therefore, the present invention can perform the synthesis of the boron nitride nanotubes 20 by forming a thermal plasma jet P using a DC plasma torch, including nitrogen as a reaction gas, and further adding ammonia and hydrogen. .

After the precursors (P1, P2) materials are vaporized by the thermal plasma jet (P), saturated vapor generates B nucleons in a rapidly cooled environment, and as nitrogen atoms in the surroundings bind to B nucleons and grow, boron nitride nanoparticles Particles 10 or boron nitride nanotubes 20 may be synthesized.

2 is a schematic diagram showing an apparatus 100: 100a for manufacturing a boron nitride nanotube according to an embodiment of the present invention. Hereinafter, the manufacturing apparatuses 100 (100a, 100b, and 100c) of FIGS. 2 to 4 may be understood as an apparatus for performing the mechanism for synthesizing the boron nitride nanotubes 20 described above in FIG. 1.

Referring to FIG. 2, the boron nitride nanotube manufacturing apparatus 100: 100a may include a reaction body 110, a plasma unit 120, a reaction gas supply unit 130, and a precursor supply unit 140.

The reaction body 110 constitutes the exterior of the boron nitride nanotube manufacturing apparatus 100, and the space where the thermal plasma jet P is formed from the plasma unit 120 and the reaction gases S1 and S2 and the precursor P1, A space in which the boron nitride nanotubes 20 are formed may be provided according to the supply of P2). This space corresponds to a reaction region in which the BN powder is sufficiently vaporized and grows into the boron nitride nanotubes 20, and may include a path in which the thermal plasma jet P is formed.

A graphite liner unit 115 may be installed on the inner wall of the reaction body 110. The synthesis of the boron nitride nanotubes 20 requires maintaining a temperature of 3,000° C. or higher, and the graphite liner unit 115 may serve as an insulating material for the reaction body 110. In addition, as the graphite liner unit 115 is installed along the inner wall of the reaction body 110 to correspond to the shape of the reaction body 110, a reaction gas passing through the high temperature region by forming turbulence in the plasma region P ( It may contribute to improving the vaporization and synthesis efficiency by increasing the residence time of S1, S2) and the precursors P1, P2.

The plasma unit 120 may be disposed at one end of the reaction body 110. At least one plasma unit 120 may be disposed. In FIG. 2, the plasma unit 120 is disposed at one end (top left) of the inclined first path of the reaction body 110, and the second path extends horizontally at the other end (bottom right) of the first path. The plasma unit 120 is arranged at one end (left end) of the second path. The precursor supply unit 140 may be connected near the plasma unit 120 to the first path. The other end (right end) of the second path may be connected to a cyclone, a filter part, a collection part, etc. from which the synthesized boron nitride nanotubes 20 are recovered.

It is preferable that the plasma unit 120 includes a DC plasma torch. As described above in FIG. 1, RF plasma can evaporate raw materials at an ultra-high temperature of 10,000 K or higher, but it is required to perform high-frequency matching and use argon (Ar) as a discharge gas, so there are many restrictions on the use environment and high cost. have. On the other hand, DC plasma does not use argon as a discharge gas, and its temperature is 3,000~6,000K, which is lower than RF plasma, but it can be mass-produced at low cost due to its easy use environment and expandability, and nitrogen is used as a discharge gas even when the temperature range is low. Therefore, it is possible to generate abundant nitrogen radicals, and there is an easy effect in synthesizing the boron nitride nanotubes 20 in large quantities through addition of hydrogen and ammonia.

In addition, the boron nitride nanotube 20 is important to create a high-temperature environment sufficient for the boron nitride to grow into a tube. DC plasma has excellent expandability and a structure or multi-stage extending the first and second paths as in the present invention. Since it is composed of the structure of the raw material to sufficiently stay in the high temperature region, there is an advantage of easy vaporization or nanotube growth.

The reactive gas supply unit 130 may supply reactive gases S1 and S2 to a space in which thermal plasma is formed. The reactive gas supply unit 130 may be integral with the plasma unit 120. As the reactive gas supply unit 130 is installed through the interior of the plasma unit 120, the reactive gases S1 and S2 may be discharged from the ends of the plasma unit 120. The reaction gas S1 may contain nitrogen, and H ₂ or NH ₃ as the reaction gas S2 may be further supplied to the reaction gas supply unit 130. Nitrogen, ammonia, or hydrogen induces the formation of NH and decomposes it again to convert it into an N radical, so that bonding with B contained in the precursor can be facilitated.

The precursor supply unit 140 may supply precursors P1 and P2 to a space in which thermal plasma is formed. The precursor supply unit 140 is installed at a location separate from the plasma unit 120 and the reaction gas supply unit 130 to supply the precursors P1 and P2 into the reaction body 110. The precursor supply unit 140 is preferably installed near the initial region where the thermal plasma jet P is formed. The precursor P1 may be B, the precursor P2 may be BN, or the like, and the precursors P1 and P2 may be injected into the initial space in which the thermal plasma jet P is formed in the reaction body 110. Accordingly, since the precursors P1 and P2 are synthesized with the reaction gases S1 and S2 over a wide plasma jet P region, there is an advantage that the efficiency of synthesis may be improved.

3 is a schematic diagram showing an apparatus for manufacturing boron nitride nanotubes 100 (100b, 100c) according to another embodiment of the present invention.

Referring to FIG. 3, the boron nitride nanotube manufacturing apparatus 100: 100b is a structure in which productivity is further improved in the embodiment of FIG. 2. In FIG. 3, there may be a plurality (eg, three) of the first inclined paths of the reaction body 110. The plasma unit 120 may be disposed at one end (top left) of the plurality of inclined first paths, and the second path may extend horizontally at the other end (bottom right) of the first path. The second path communicates with the other end (lower right) of each of the first paths, and the plasma unit 120 may be further disposed at one end (left end) of the second path. The precursor supply unit 140 may be connected to each of the first paths near the plasma unit 120. The other end (right end) of the second path may be connected to a cyclone, a filter part, a collection part, etc. from which the synthesized boron nitride nanotubes 20 are recovered.

4 is a side cross-sectional view (a) and a plan schematic view (b) showing an apparatus for manufacturing boron nitride nanotubes according to another embodiment of the present invention.

Referring to FIG. 4, the boron nitride nanotube manufacturing apparatus 100: 100c is a structure in which productivity and efficiency of synthesis are further improved. 4 shows a form in which three plasma units 120 are radially disposed at one end of the reaction body 110 at predetermined intervals from each other. Any straight line extending from the three plasma units 120 may be in contact with each other in the inner space of the reaction body 110. To this end, the three plasma units 120 may be arranged to be inclined at a predetermined angle with respect to the horizontal plane. Accordingly, the thermal plasma jets P generated by the three plasma units 120 are concentrated in one place to increase the vaporization rate of the raw material. Although three plasma units 120 are illustrated in FIG. 4 as an example, the number of plasma units 120 can be increased or decreased within a range for the purpose of concentrating the thermal plasma jet P in one place of the plurality of plasma units 120. .

In particular, precursors (P1, P2) and reactive gases in a space where an arbitrary straight line extending from the three plasma units 120 is in contact with the inner space of the reaction body 110, that is, a portion where the thermal plasma jet (P) is concentrated. It is preferable to supply (S1, S2). Accordingly, the precursor supply unit 140 may be disposed directly above the thermal plasma jet P to supply the precursors P1 and P2.

Hereinafter, experimental examples for understanding the characteristics of the boron nitride nanotubes manufactured by the boron nitride nanotube manufacturing apparatus 100 of the present invention will be described. However, the following experimental examples are only for aiding understanding of the present invention, and embodiments of the present invention are not limited to the following experimental examples.

5 shows a composite photo (a) and an SEM photo (b) of boron nitride nanotubes according to an embodiment of the present invention.

The inside of the reaction body 110 is maintained at normal pressure, and h-BN powder (~1㎛m 98%, 255475, Sigma-Aldrich, Inc.) as a precursor, N _{2 8} slpm and H ₂ 8 slpm as discharge gas and reaction gas. Supplied. With the arc current fixed at 100A, the input power of each plasma torch was applied at about 6.9~7.5kW. Referring to FIG. 5A, it can be seen that boron nitride nanotubes are synthesized in a size of about 10 cm, and boron nitride nanotubes have a layered shape and are aggregated. Further, referring to (b) of FIG. 5, it can be seen that boron nitride has a tube shape and is synthesized.

6 shows a TEM photograph of the synthesized boron nitride nanotubes according to an embodiment of the present invention. Referring to FIG. 6, it can be seen that the boron nitride nanotubes have a diameter of about 2.7 to 4.9 nm smaller than 5 nm and are manufactured in a tube shape including 1 to 3 walls.

As described above, the present invention has advantages in that plasma control is easy, continuous process is possible, and mass synthesis of boron nitride nanotubes is possible. In addition, there is an advantage of inducing a fast reaction rate by intensively applying plasma thermal energy according to the arrangement of the plasma unit, and there is an effect that mass production can be performed at low cost using DC plasma.

Although the present invention has been illustrated and described with reference to a preferred embodiment as described above, it is not limited to the above embodiment, and within the scope not departing from the spirit of the present invention, various It can be transformed and changed. Such modifications and variations should be viewed as falling within the scope of the present invention and the appended claims.

100: boron nitride nanotube manufacturing apparatus
110: reaction body
115: graphite liner
120: plasma unit
130: reaction gas supply
140: precursor supply unit
P: thermal plasma jet
P1, P2: precursor
S1, S2: reaction gas

Claims (10)

As an apparatus for manufacturing boron nitride nanotubes,
A reaction body providing a space in which a thermal plasma jet and boron nitride nanotubes are formed;
A DC plasma torch, at least one plasma unit disposed at one end of the reaction body and generating thermal plasma;
A precursor supply unit supplying a precursor to a space in which a thermal plasma is formed; And
Reactive gas supply unit that supplies reactive gas to the space where thermal plasma is formed
Including,
The precursor contains boron, the reaction gas contains nitrogen,
Further supplying ammonia or hydrogen to the reaction gas supply,
Boron nitride nanotube manufacturing apparatus capable of manufacturing boron nitride nanotubes at a lower temperature than RF plasma torch without using argon as a reaction gas compared to the case of using a DC plasma torch in the plasma section and using an RF plasma torch . delete delete The method of claim 1,
Boron nitride nanotube manufacturing apparatus in which boron nitride nanotubes are formed by thermal plasma of 3,000K to 6,000K temperature. delete The method of claim 1,
An apparatus for manufacturing boron nitride nanotubes in which a graphite liner part is installed on the inner wall of the reaction body. The method of claim 1,
The reaction body includes a first path and a second path communicating at an angle to an end of the first path, and one plasma unit is disposed in each of the first path and the second path,
Boron nitride nanotube manufacturing apparatus, the precursor supply is connected to the first path. The method of claim 1,
The reaction body includes a plurality of first paths and a second path communicating at a predetermined angle to ends of the plurality of first paths, and one plasma unit is disposed in each of the first paths and the second paths,
Boron nitride nanotube manufacturing apparatus, the precursor supply is connected to the first path. The method of claim 1,
The three plasma units are radially arranged at one end of the reaction body at predetermined intervals,
The apparatus for manufacturing boron nitride nanotubes, wherein the plasma unit is disposed to be inclined at a predetermined angle with respect to a horizontal plane such that an arbitrary straight line extending from the three plasma units contacts the inner space of the reaction body. The method of claim 9,
An apparatus for manufacturing a boron nitride nanotube for supplying a precursor and a reaction gas to a space in which an arbitrary straight line extending from the three plasma units is in contact with the inner space of the reaction body.

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