Vanadium carbides having oxygen content of 4000 ppm or less and carbon content of less than 15 weight percent

Abstract

The present invention provides a vanadium carbide having an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt.%, which can implement a MAX and MXene production process excluding expensive metal vanadium, the oxygen content of the vanadium carbide being as low as 4000 ppm or less and the carbon content being less than 15 wt.%, and the crystal system being a mixture of the trigonal system and the cubic system.

Description

Technical Field

[0001] The present invention relates to a vanadium carbide having an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%, which can realize a process for preparing MAX and MXene excluding expensive metallic vanadium. The vanadium carbide has an oxygen content as low as 4000 ppm or less and a carbon content of less than 15 wt%, and its crystal system exhibits a mixture of trigonal and cubic crystal systems. Background Art

[0002] MXene, a two-dimensional carbide, is composed of a transition metal and carbon and is prepared by selectively etching MAX, a ternary crystalline carbide.

[0003] The chemical formula of MAX is M n+1 AX n , and when the A layer is removed by selective etching, two-dimensional MXene of Mn+1Xn is obtained. The transition metals included in M are generally Ti, V, Cr, Mo, Nb, etc., the elements corresponding to A include Al, Si, and C and N as non-metallic elements are located at the X position.

[0004] Among them, when Al and Si at the A position in MAX are removed using hydrofluoric acid or hydrochloric acid, the crystalline MAX is transformed into two-dimensional MXene.

[0005] Generally, crystalline MAX is synthesized by the reaction of a metal (M, A) and a non-metallic element (X), but there is a problem in that the cost of the transition metal is high.

[0006] Therefore, through long-term painstaking efforts and various studies by the applicant, a vanadium carbide having an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% has been obtained, which can realize a process for preparing MAX and MXene excluding expensive metallic vanadium. The vanadium carbide has an oxygen content as low as 4000 ppm or less and a carbon content of less than 15 wt%, and its crystal system exhibits a mixture of trigonal and cubic crystal systems, thus completing the present invention.

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Korean Patent No. 10-0430701 (authorized on April 27, 2004) Summary of the Invention

[0010] Technical Problem

[0011] Accordingly, an object of the present invention is to provide a vanadium carbide having an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%, which can achieve the MAX and MXene preparation processes excluding expensive metallic vanadium. The vanadium carbide has an oxygen content as low as 4000 ppm or less and a carbon content of less than 15 wt%, and the crystal system exhibits a mixture of trigonal and cubic crystal systems.

[0012] The problems to be solved by the present invention are not limited to the above problems, and those of ordinary skill in the art can clearly understand other problems not mentioned through the following description.

[0013] Technical solution

[0014] To solve the above problems, according to one aspect of the present invention, there is provided a vanadium carbide having an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%, with the chemical formula V 2 C x and VC y , where the range of x is 0.5 ≤ x ≤ 0.75, the range of y is 0.5 ≤ y ≤ 0.75, and the crystal system exhibits a mixture of trigonal crystal system (V 2 C x ) and cubic crystal system (VC y ).

[0015] According to an embodiment of the present invention, the oxygen content of the vanadium carbide having an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% can be 10 ppm to 4000 ppm.

[0016] According to an embodiment of the present invention, the total carbon content of the vanadium carbide having an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% can be 10.5 - 15 wt%.

[0017] According to an embodiment of the present invention, the particle size of the vanadium carbide having an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% can be 2 nm to 50 μm.

[0018] Advantages of the invention

[0019] According to the present invention, there is provided a vanadium carbide having an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%, which can achieve the MAX and MXene preparation processes excluding expensive metallic vanadium. The vanadium carbide has an oxygen content as low as 4000 ppm or less and a carbon content of less than 15 wt%, and the crystal system exhibits a mixture of trigonal and cubic crystal systems. Therefore, the vanadium carbide can be used as a raw material to achieve low-cost MAX and MXene preparation processes, and the prepared MAX and MXene have a low oxygen content and excellent electrical conductivity.

[0020] Moreover, the present invention provides a method for preparing vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%, which can achieve the MAX and MXene preparation processes excluding expensive metallic vanadium. The vanadium carbide has an oxygen content as low as 4000 ppm or less and a carbon content of less than 15 wt%, and its crystal system shows a mixture of trigonal and cubic crystal systems. Therefore, it has excellent process stability and is economical due to large-scale production.

[0021] The effects of the present invention are not limited to the above effects, and it should be understood to include all effects that can be inferred from the structure of the invention described in the detailed description or the scope of the invention claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 FIG. 1 is a process flow chart showing a method for preparing vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% according to an embodiment of the present invention.

[0023] FIG. 2 is a graph showing (a) the carbon content and (b) the oxygen content of vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% according to an embodiment of the present invention.

[0024] Figure 3 FIG. 3 is a phase diagram showing vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% according to an embodiment of the present invention.

[0025] Figure 4 FIG. 4 is an XRD crystal structure graph showing vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] Preferred embodiments of the present invention will be described in detail with reference to the following drawings.

[0027] The advantages, features, and implementation methods of the present invention will be made clear by referring to the embodiments described in detail below together with the Figure 1 accompanying drawings.

[0028] However, the present invention is not limited to the embodiments disclosed below and can be implemented in various different forms. These embodiments are only used to fully disclose the present invention and are provided to fully inform those of ordinary skill in the art to which the present invention pertains of the scope of the invention. The present invention is only defined by the scope of the claims.

[0029] Moreover, in the process of describing the present invention, when it is determined that related well-known technologies may obscure the gist of the present invention, detailed descriptions thereof will be omitted.

[0030] Hereinafter, the present invention will be described in detail.

[0031] Vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%

[0032] The present invention provides a vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%, which can achieve the MAX and MXene preparation processes excluding expensive metallic vanadium. The oxygen content of the vanadium carbide is as low as 4000 ppm or less and the carbon content is less than 15 wt%, and the crystal system exhibits a mixture of trigonal and cubic crystal systems.

[0033] The vanadium carbide of the present invention with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% has a chemical formula of V 2 C x and VC y , where the range of x is 0.5 ≤ x ≤ 0.75, the range of y is 0.5 ≤ y ≤ 0.75, and the crystal system exhibits a mixture of trigonal (V 2 C x ) and cubic (VC y ) crystal systems.

[0034] The present invention provides a vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%, which can achieve the MAX and MXene preparation processes excluding expensive metallic vanadium. The oxygen content of the vanadium carbide is as low as 4000 ppm or less and the carbon content is less than 15 wt%, and the crystal system exhibits a mixture of trigonal and cubic crystal systems. Therefore, the vanadium carbide can be used as a raw material to achieve low-cost MAX and MXene preparation processes, and the prepared MAX and MXene have a low oxygen content and excellent electrical conductivity.

[0035] MXene, as a two-dimensional carbide, is composed of transition metals and carbon and is prepared by selectively etching MAX, a ternary crystalline carbide.

[0036] The chemical formula of MAX is M n+1 AX n , and when the A layer is removed by selective etching, two-dimensional MXene of M n+1 X n is obtained. The transition metals included in M are generally Ti, V, Cr, Mo, Nb, etc., the elements corresponding to A include Al, Si, and the non-metallic elements C, N are located at the X position.

[0037] Among them, when Al and Si at the A position in MAX are removed using hydrofluoric acid or hydrochloric acid, the crystalline MAX is transformed into two-dimensional MXene.

[0038] Generally, crystalline MAX is synthesized by the reaction of metals (M, A) with non-metal elements (X), but there is a problem of high cost of transition metals.

[0039] Therefore, through long-term hard work and various researches, the applicant has obtained vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%, and its preparation method, which can realize the MAX and MXene preparation processes excluding expensive metal vanadium. The oxygen content of the vanadium carbide is as low as 4000 ppm or less and the carbon content is less than 15 wt%, and the crystal system shows a mixture of trigonal and cubic crystal systems, thus completing the present invention.

[0040] Among them, the present invention can be vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%, which can realize the MAX and MXene preparation processes excluding expensive metal vanadium. The oxygen content of the vanadium carbide is as low as 4000 ppm or less and the carbon content is less than 15 wt%, and the crystal system shows a mixture of trigonal and cubic crystal systems.

[0041] That is, the crystal system of the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% can show a trigonal crystal system (V 2 C x ) and a cubic crystal system (VC y ).

[0042] Among them, the trigonal crystal system (V 2 C x ; R-3m) is a rhombohedral crystal system, the lengths of its three vectors are all the same, and the angles formed by each axis are all non-right-angled shapes, showing a form of stretching the cube in the diagonal direction.

[0043] Moreover, the cubic crystal system (VC y ; Fm-3m) is a cubic crystal system, its unit cell is in the shape of a cube, and the three crystal axes are perpendicular to each other.

[0044] And, the oxygen content of the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% can be 10 ppm to 4000 ppm.

[0045] Among them, when the oxygen content is within the above range, it may not be easy to form oxygen carbide in the form of V(C x O 1-x ) with a large amount of oxygen.

[0046] Moreover, when the oxygen content is greater than 4000 ppm, there is a problem that aluminum oxide as an oxide may be formed during the MAX synthesis process, and VC may be formed due to the lack of aluminum, resulting in a decrease in the MAX phase fraction.

[0047] In this case, preferably, the oxygen content may be 30 ppm to 4000 ppm, and more preferably, it may be 100 ppm to 4000 ppm.

[0048] Moreover, the chemical formula of the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% may be V 2 C x and VC y , where the range of x may be 0.5 ≤ x ≤ 0.75, and the range of y may be 0.5 ≤ y ≤ 0.75.

[0049] Among them, when the ranges of x and y are within the above ranges, the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% may not easily form an oxycarbide in the form of V(C x O 1-x ).

[0050] Specifically, the MAX synthesis cost can be reduced by using transition metal carbides instead of transition metals.

[0051] And, the reaction formula of vanadium-based MAX is as follows.

[0052] Reaction formula 1: 2VC 0.5 + Al → V 2 AlC

[0053] Reaction formula 2: 4VC 0.75 + Al → V 4 AlC 3

[0054] Reaction formula 3: 12VC 0.67 + 3Al → V 12 Al 3 C 8

[0055] And, the total carbon content of the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% may be 10.5 to 15 wt%.

[0056] Among them, when the total carbon content of the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% is less than 10.5 wt%, there is a problem of adding carbon during the MAX synthesis process, and when it is greater than 15 wt%, there is a problem of adding metallic vanadium during the MAX synthesis process.

[0057] Moreover, the particle size of the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% can be 2 nm to 50 μm.

[0058] Among them, preferably, the particle size of the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% can be 100 nm to 50 μm, and more preferably, it can be 500 nm to 50 μm.

[0059] Method for preparing vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%

[0060] The present invention provides a method for preparing vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%, which can achieve the MAX and MXene preparation processes excluding expensive metallic vanadium. The vanadium carbide has an oxygen content as low as 4000 ppm or less and a carbon content of less than 15 wt%, and the crystal system shows a mixture of trigonal and cubic crystal systems.

[0061] The present invention relates to a method for preparing vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%, and the method comprises:

[0062] Step (a-1), preparing a mixed powder by mixing a vanadium oxide and a carbon compound;

[0063] Step (a-2), putting the mixed powder and steel balls into a rotating container in a high-energy grinding device;

[0064] Step (a-3), inputting high energy of 0.6 J / g·s to 2.4 J / g·s in an atmosphere of air, vacuum, nitrogen or argon, and performing high-energy grinding by rotating the rotating shaft and the rotating container in opposite directions to each other to prepare a fine powder; and

[0065] Step (a-4), preparing vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% by performing vacuum heat treatment on the fine powder to carry out a carbothermal reduction reaction.

[0066] The present invention provides a method for preparing vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%, which can achieve the MAX and MXene preparation processes excluding expensive metallic vanadium. The vanadium carbide has an oxygen content as low as 4000 ppm or less and a carbon content of less than 15 wt%, and the crystal system shows a mixture of trigonal and cubic crystal systems. Therefore, it has excellent process stability and is economical due to large-scale production.

[0067] Moreover, in the step (a-1) of preparing the mixed powder by mixing vanadium oxide and carbon compound,

[0068] the mixing ratio of the vanadium oxide to the carbon compound may be 1:0.2 to 1:0.7 by weight.

[0069] Among them, when the mixing ratio of the vanadium oxide to the carbon compound is within the above range by weight, it may not be easy to form an oxycarbide in the form of V(C x O 1-x ) with a large amount of oxygen.

[0070] In this case, preferably, the mixing ratio of the vanadium oxide to the carbon compound may be 1:0.4 to 1:0.6 by weight, and more preferably, it may be 1:0.45 to 1:0.55 by weight.

[0071] Moreover, the vanadium oxide may be at least one selected from pentavanadium oxide (V 2 O 5 ), sodium metavanadate (NaVO 3 ), trivanadium oxide (V 2 VO 3 ), vanadyl chloride (VOCl 3 ), and ammonium metavanadate (H 4 NVO 3 ).

[0072] Among them, when using vanadium oxide (V 2 O 5 ) as the raw material for synthesizing vanadium carbide, through the reaction of vanadium oxide with carbon, that is, through carbothermal reduction, vanadium carbide as shown in the following reaction formula 4 is formed.

[0073] Reaction formula 4: V 2 O 5 +7C→2VC+5CO

[0074] In this process, theoretically, if the carbon content is adjusted to less than 7 moles relative to 1 mole of vanadium oxide, vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% in the form of VC x can be synthesized.

[0075] However, in the actual process, when reducing the carbon content acting as a reducing agent, since the reduction reaction rate decreases, it is easy to form an oxycarbide in the form of V(C x O 1-x ) with a large amount of oxygen.

[0076] Moreover, in order to form vanadium carbide, not only the carbon content needs to be adjusted, but also a treatment for increasing the rate of the carbothermal reduction reaction is required.

[0077] In the present invention, the particle size of the mixed powder of vanadium oxide and carbon as raw materials is reduced to the above range through a high-energy milling process to increase the reaction rate, thereby synthesizing vanadium carbide with a low oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%.

[0078] And the carbon compound is at least one selected from industrial carbon powder, coke, coal, coal tar, activated carbon, graphite, natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, pyrolytic carbon black, industrial diamond, and carbon fiber.

[0079] Among them, the carbon compound may further include at least one biomass selected from coffee grounds, fallen leaves, and waste wood.

[0080] And the carbon compound may further include at least one carbon-containing reducing gas selected from carbon monoxide, methane, and hydrocarbons.

[0081] Moreover, the mixed powder after mixing the vanadium oxide and the carbon compound is placed together with steel balls into a rotating container in a high-energy milling device, and then the high-energy milling is carried out in an atmosphere of air, vacuum, nitrogen, or argon. At this time, a high energy of 0.6 J / g·s to 2.4 J / g·s is input, the rotating shaft rotates at 150 to 300 rpm, and the rotating container rotates at 300 to 600 rpm in a direction opposite to the rotation direction of the rotating shaft, and high-energy milling can be carried out for 1 to 20 hours.

[0082] And in the step (a-2) of placing the mixed powder together with steel balls into a rotating container in a high-energy milling device, the high-energy milling device may be a planetary ball mill, a Spex ball mill, or a grinder.

[0083] Among them, the planetary ball mill can reduce the particle size of the mixed powder of the vanadium oxide and the carbon compound to the above range by loading steel balls and raw materials into a container together and making the container perform rotational and orbital motions at high speed.

[0084] And the Spex ball mill can reduce the particle size of the mixed powder of the vanadium oxide and the carbon compound to the above range by loading steel balls and raw materials into a container together and making the container perform up-and-down and left-and-right vibration motions at high speed.

[0085] Moreover, the grinder can reduce the particle size of the mixed powder of the vanadium oxide and the carbon compound to the range by loading steel balls and raw materials into a container and transferring energy through the rotational force of a rotor.

[0086] Furthermore, the high-energy grinding device can reduce the particle size of the mixed powder of the vanadium oxide and the carbon compound to the range by rotating a rotating container equipped with the mixed powder of the vanadium oxide and the carbon compound on a rotating disk in a direction opposite to the rotation direction of the rotation axis of the rotating disk.

[0087] Moreover, in the step (a-2) of putting the mixed powder and steel balls into the rotating container of the high-energy grinding device, the steel balls can be at least one selected from ceramic balls, metal balls, and cemented carbide balls.

[0088] Specifically, the material of the steel balls can be steel, tungsten, or zirconia.

[0089] Among them, the shape of the steel balls can be at least one selected from spherical, star-shaped, conical, and cylindrical.

[0090] And, in the step (a-3) of preparing the fine powder by inputting high energy of 0.6 J / g·s to 2.4 J / g·s in an atmosphere of air, vacuum, nitrogen, or argon, and performing high-energy grinding by rotating the rotating shaft and the rotating container in opposite directions to each other,

[0091] the rotating shaft rotates at 150 - 300 rpm, the rotating container rotates at 300 - 600 rpm in a direction opposite to the rotation direction of the rotating shaft, and high-energy grinding can be performed for 1 - 20 hours.

[0092] Among them, the high-energy grinding can be the following process: inputting energy of 0.6 J / g·s to 2.4 J / g·s, making the rotation directions of the rotating shaft and the rotating container opposite to each other, and grinding the steel balls put into the rotating container and the mixed powder of the vanadium oxide and the carbon compound against each other to crush the particles of the mixed powder of the vanadium oxide and the carbon compound, so as to reduce the average particle size of the mixed powder to 2 nm to 50 μm.

[0093] Moreover, in the step (a-4) of preparing vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% by performing vacuum heat treatment on the fine powder to carry out a carbothermal reduction reaction,

[0094] the heat treatment temperature of the vacuum heat treatment can be 800°C to 1600°C, and the heat treatment time can be 10 minutes to 24 hours.

[0095] Among them, when the heat treatment temperature of the vacuum heat treatment is within the above range, vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% can have excellent oxygen reduction characteristics and preparation efficiency.

[0096] That is, the mixed powder of vanadium oxide and carbon compound generated by the high-energy grinding device can be subjected to vacuum heat treatment at the heat treatment temperature of the vacuum heat treatment to prepare vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%, which has excellent oxygen reduction characteristics and preparation efficiency.

[0097] In this case, preferably, the heat treatment temperature of the vacuum heat treatment can be 850°C to 1600°C, and more preferably, it can be 900°C to 1600°C.

[0098] Moreover, when the heat treatment time of the vacuum heat treatment is within the above range, vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% can have excellent oxygen reduction characteristics and preparation efficiency.

[0099] That is, the mixed powder of vanadium oxide and carbon compound generated by the high-energy grinding device can be subjected to vacuum heat treatment during the heat treatment time of the vacuum heat treatment to prepare vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%, which has excellent oxygen reduction characteristics and preparation efficiency.

[0100] In this case, preferably, the heat treatment time of the vacuum heat treatment can be 20 minutes to 24 hours, and more preferably, it can be 30 minutes to 24 hours.

[0101] Figure 1 The process flow chart shows a method for preparing vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% according to an embodiment of the present invention.

[0102] Reference Figure 1 , first, a mixed powder is prepared by mixing vanadium oxide and carbon compound (S110).

[0103] Then, the mixed powder and steel balls are placed together in a rotating container in a high-energy grinding device (S120).

[0104] Next, high energy of 0.6 J / g·s to 2.4 J / g·s is input under an atmosphere of air, vacuum, nitrogen or argon, and high-energy grinding is performed by rotating the rotating shaft and the rotating container in opposite directions to each other to prepare a fine powder (S130).

[0105] Then, the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% is prepared by subjecting the subdivision to vacuum heat treatment to carry out a carbonization reduction reaction (S140).

[0106] Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are for more specifically illustrating the present invention, and the scope of the present invention is not limited to the following examples. The following examples can be appropriately modified and changed by those of ordinary skill in the art within the scope of the present invention.

[0107] Example

[0108] Examples 1 to 7: Preparation of vanadium with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% carbide

[0109] A mixed powder of vanadium oxide and carbon compound is prepared using the components and contents shown in Table 1 below.

[0110] Then, the mixed powder and steel balls are placed in a rotating container in a high-energy grinding device.

[0111] Next, in the high-energy grinding device, high energy as shown in Table 1 below is input under an atmosphere of air, vacuum, nitrogen, or argon, which is the gas condition when pulverizing particles, and high-energy grinding is carried out by rotating the rotating shaft and the rotating container in opposite directions to each other to prepare a subdivision.

[0112] Then, the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% is prepared by subjecting the subdivision to vacuum heat treatment under the conditions shown in Table 1 below to carry out a carbonization reduction reaction.

[0113] Comparative example: Preparation of vanadium carbide

[0114] Except for using a high-energy grinding device in Example 4, vanadium carbide of the comparative example is prepared in the same manner as in Example 4.

[0115] Table 1

[0116]

[0117] Referring to Table 1, the oxygen content of the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% in Examples 1 to 7 is 1440 ppm to 3870 ppm, which is significantly less than that of the vanadium carbide of the comparative example with an oxygen content of 12000 ppm.

[0118] Therefore, the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% in Examples 1 to 7 exhibits a small amount of oxygen.

[0119] Moreover, the average particle size of the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% in Examples 1 to 7 is 500 nm, which shows a very small average particle size compared to the vanadium carbide of the comparative example with an average particle size of 10 μm.

[0120] Therefore, it can be confirmed that the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% in Examples 1 to 7 is a vanadium carbide with a significantly lower oxygen content and a significantly lower average particle size compared to the comparative example.

[0121] Experimental example

[0122] Experimental example 1: Carbon content and oxygen content of vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% and oxygen content

[0123] The curves of the carbon content and the oxygen content of the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% prepared in Examples 1 to 7 are shown in Fig. 2.

[0124] Fig. 2 is a graph showing (a) the carbon content and (b) the oxygen content of the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% according to Examples 1 to 7.

[0125] Reference Figure 2a , the carbon content of the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% in Examples 1 to 7 is 10.5 wt% to 17.5 wt%.

[0126] And, reference Figure 2b , the oxygen content of the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% in Examples 1 to 7 is 1440 ppm to 3870 ppm, which is very low.

[0127] Experimental example 2: Analysis of the crystal structure of vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt%

[0128] The state diagrams of the vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% prepared in Examples 1 to 7 are shown in Figure 3 and the XRD crystal structures are shown in Figure 4 .

[0129] Figure 3To show the phase diagram of vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% according to Embodiments 1 to 7.

[0130] As Figure 3 shown in the V-C binary phase diagram, it is confirmed that vanadium carbide with an appropriate carbon content consists of two phases, V 2 C x (R-3m) and VC y (Fm-3m).

[0131] Figure 4 To show the XRD crystal structure curve of vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% according to Embodiments 1 to 7.

[0132] Referring to Figure 4 , it is confirmed that Embodiments 1 to 3 consist of two phases, V 2 C x (R-3m) and VC y (Fm-3m).

[0133] So far, specific embodiments related to vanadium carbide with an oxygen content of 4000 ppm or less and a carbon content of less than 15 wt% of the present invention have been described. However, it is obvious that various implementation modifications can be made without departing from the scope of the present invention.

[0134] Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the scope of the invention claimed hereinafter and its equivalents.

[0135] That is, it should be understood that the embodiments are exemplary in all aspects and not restrictive. The scope of the present invention is indicated by the scope of the invention claimed hereinafter rather than the detailed description, and should be interpreted to include all modifications or variations derived from the meaning, scope, and equivalent concepts of its claimed scope of the invention.

Claims

1. A vanadium carbide having an oxygen content of less than 4000 ppm and a carbon content of less than 15 weight percent, characterized in that: The chemical formula is V2C x and VC y , the range of x is 0.5≤x≤0.75, the range of y is 0.5≤y≤0.75, and the crystal system is trigonal V2C x and cubic VC y A mixture of.

2. The vanadium carbide having an oxygen content of less than 4000 ppm and a carbon content of less than 15 weight percent according to claim 1, characterized in that: The vanadium carbide having an oxygen content of less than 4000 ppm and a carbon content of less than 15 weight percent has an oxygen content of 10 ppm to 4000 ppm.

3. The vanadium carbide having an oxygen content of less than 4000 ppm and a carbon content of less than 15 weight percent according to claim 1, characterized in that: The vanadium carbide having an oxygen content of less than 4000 ppm and a carbon content of less than 15 weight percent has a total carbon content of 10.5 to 15 weight percent.

4. The vanadium carbide having an oxygen content of less than 4000 ppm and a carbon content of less than 15 weight percent according to claim 1, characterized in that: The vanadium carbide having an oxygen content of less than 4000 ppm and a carbon content of less than 15 weight percent has a particle size of 2 nm to 50 μm.

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