Rapid method for producing transition metal borides

Abstract

The present invention relates to a method for the rapid preparation of transition metal borides, which comprises the steps of: using a tungsten rod as a cathode, and using a mixture of boron powder and metal oxide pressed into a lump as an anode, placing the lump mixture and the tungsten rod in an arc furnace; filling the arc furnace with a buffer gas after evacuating the arc furnace and controlling the arc to start an arc, and controlling the arc furnace to close the arc immediately after igniting the lump mixture, so that the lump mixture undergoes a continuous combustion reaction to obtain transition metal borides. The present invention uses a direct current arc plasma method to prepare the transition metal borides, which has the advantages of simple operation, low cost, environmental friendliness, and controllable reaction atmosphere, and the preparation process is simple, rapid, and has no impact on the environment.

Description

Technical Field

[0001] The present invention relates to a rapid manufacturing method of transition metal boride and belongs to the field of nanomaterials by the DC arc method.

Background Art

[0002] In recent years, transition metal borides (TMBs) have attracted great interest due to their unique mechanical and electrical properties. This compound has excellent properties such as a large bulk modulus of elasticity, high hardness, ultra-high melting point, good thermal stability, strong oxidation resistance, and excellent electrical transmission performance. Therefore, it is widely used in fields such as super combustion press engines, rocket propulsion, hypersonic flight, atmospheric reentry, electro-mechanical system hard coats, studded claws, and cutting tools. For example, titanium diboride, as one of the emerging engineering ceramic materials, has characteristics such as high hardness, high modulus of elasticity, high melting point, excellent wear resistance, and excellent thermal conductivity and conductivity. Baharvandi et al. synthesized a B4C-TiB2 composite ceramic material by using B4C and TiB2 as raw materials and sintering at a temperature of 2050 / 2150 °C under no pressure. The addition of TiB2 can reduce the porosity and suppress the grain growth. At the same TiB2 content, the higher the synthesis temperature, the better the density.

[0003] Common methods for producing transition metal borides include reducing a mixture of boron halide and metal halide with hydrogen gas, reducing a mixture of boron trioxide and metal oxide with carbon, and reducing metal oxides with electrolytic molten salts and monoboron. While these methods are widely used for producing metal borides, they have several drawbacks. For example, reducing a mixture of boron halide and metal halide with hydrogen gas, or thermally decomposing a mixture of boron halide and volatile metal halide on a wire in hydrogen gas, can produce small amounts of pure metal boride. Reducing a mixture of diboron trioxide and metal oxide with carbon allows for the production of relatively large quantities of metal boride. However, at high temperatures, the different volatility of the various oxides can cause changes in chemical composition, and the product is highly susceptible to contamination by boron, boron carbide, and carbon generated in the process. Regarding the electrolytic molten salt method, this method can produce many metal borides, some of which have already reached industrial production levels. However, the current efficiency is low, and the material phases and products that may generate several borides are difficult to separate purely from the molten salt. Moreover, some of the above methods have long manufacturing times, and impurities generated during the manufacturing process may require additional processing.

[0004] Therefore, there is still room for improvement and development in the prior art. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In light of the shortcomings of the prior art described above, the object of this application is to provide a rapid method for producing transition metal borides, which aims to solve the technical problems of conventional production processes for transition metal borides, such as their complexity and significant environmental impact.

[0006] The present invention provides a rapid method for producing transition metal borides, employing the following technical solutions.

[0007] A tungsten rod and a lump mixture of boron powder and metal oxide are prepared, and the lump mixture and the tungsten rod are placed in the arc furnace as the anode and cathode, respectively. The arc furnace is evacuated, then filled with buffer gas, the arc furnace is controlled to start the arc, the lumpy mixture is ignited, and then the arc furnace is immediately controlled to close the arc, allowing the lumpy mixture to undergo a continuous combustion reaction to obtain a transition metal boride.

[0008] In the above implementation, by providing a heat source using the arc furnace, the arc can be closed by igniting one end of the anode, and the reaction proceeds in the form of a combustion wave until the entire anode is completely reacted. The arc plasma method has advantages such as being easy to operate, low cost, environmentally friendly, and allowing control of the reaction atmosphere, and since the transition metal borides are produced rapidly, the manufacturing process is simple and does not affect the environment.

[0009] In some embodiments, the buffer gas is argon gas.

[0010] In some embodiments, the metal oxide is one of the following: tricobalt tetroxide, triiron tetroxide, high nickel oxide, titanium dioxide, and vanadium dioxide.

[0011] In some embodiments, the distance between the lump mixture and the tungsten rod within the arc furnace is 1 to 3 mm.

[0012] In some embodiments, the discharge current of the arc is 12 to 50 A, and the discharge time of the arc is 1 to 30 s.

[0013] In some embodiments, the vacuum level after evacuating the arc furnace is 3 Pa or less.

[0014] In some embodiments, the gas pressure after the buffer gas has been filled is 40 to 80 kPa.

[0015] In some embodiments, the transition metal boride includes one of nickel boride, cobalt boride, vanadium diboride, and titanium diboride.

[0016] The spacing range between the above-mentioned lump mixture and the above-mentioned tungsten rod, and the range of gas pressure in the arc furnace, can make the arc more stable. The discharge current and discharge time of the arc can be adjusted to match the above-mentioned spacing range and pressure range to improve the efficiency of metal boride production. [Brief explanation of the drawing]

[0017] [Figure 1] This is a flowchart of the rapid production method for transition metal borides according to the present invention. [Figure 2] This is a schematic diagram of an arc furnace used in the rapid production method for transition metal borides of the present invention. [Figure 3] This is the X-ray diffraction pattern of nickel boride nanoparticles prepared in Example 1 of the present invention. [Figure 4] This is a transmission electron microscope image of nickel boride nanoparticles prepared in Example 1 of the present invention. [Figure 5] This is the X-ray diffraction pattern of vanadium diboride nanoparticles prepared in Example 2 of the present invention. [Figure 6] This is a transmission electron microscope image of vanadium diboride nanoparticles prepared in Example 2 of the present invention. [Figure 7] This is the X-ray diffraction pattern of titanium diboride nanoparticles prepared in Example 3 of the present invention. [Figure 8] This is a transmission electron microscope image of titanium diboride nanoparticles prepared in Example 3 of the present invention. [Figure 9] This is the X-ray diffraction pattern of cobalt boride nanoparticles prepared in Example 4 of the present invention. [Figure 10] This is a transmission electron microscope image of cobalt boride nanoparticles prepared in Example 4 of the present invention. [Modes for carrying out the invention]

[0018] The present invention will be described in more detail below with reference to the accompanying drawings and specific examples, but the protection scope of the present invention is not limited to the above.

[0019] As shown in FIGS. 1 and 2, the rapid manufacturing method of transition metal boride provided by the present invention includes step S1 and step S2.

[0020] In step S1, a massive mixture of tungsten rod, boron powder and metal oxide is prepared, and the massive mixture and the tungsten rod are respectively placed as the anode and the cathode in an arc furnace.

[0021] In step S2, the arc furnace is evacuated, and then filled with buffer gas to control the arc furnace to start the arc. After igniting the massive mixture, the arc furnace is controlled to close the arc, and the massive mixture is continuously subjected to a combustion reaction to obtain a transition metal boride.

[0022] In the above embodiment, by using the arc furnace to provide a heat source, the arc can be closed by igniting one end of the anode, and the reaction is carried out in the form of a combustion wave until the entire anode completely reacts. Using the arc plasma method with advantages such as simple operation, low cost, environmental friendliness, and controllable reaction atmosphere, the transition metal boride is rapidly manufactured, and the manufacturing process is simple and does not affect the environment.

[0023] Optionally, the buffer gas is argon gas.

[0024] Optionally, the metal oxide is one of cobalt tetroxide, iron tetroxide, nickelous oxide, titanium dioxide, and vanadium dioxide.

[0025] Optionally, the distance between the massive mixture and the tungsten rod in the arc furnace is 1-3 mm.

[0026] Optionally, the discharge current of the arc is 12 to 50 A, and the discharge time of the arc is 1 to 30 s.

[0027] As an option, the vacuum level after evacuating the arc furnace is 3 Pa or less.

[0028] Optionally, the gas pressure after the buffer gas has been filled is 40-80 kPa.

[0029] Optionally, the transition metal boride includes one of nickel boride, cobalt boride, vanadium diboride, and titanium diboride.

[0030] The spacing range between the lump mixture and the tungsten rod, and the gas pressure range within the arc furnace, can make the arc more stable. The discharge current and discharge time of the arc can be adjusted to match the spacing range and pressure range to improve the effectiveness of metal boride production.

[0031] The rapid production method for transition metal borides provided by the present invention will be described in detail below using specific examples 1 to 5.

[0032] <Example 1> (1) Manufacturing of discharge anodes A mixture of boron powder and high nickel oxide in a 6:1 ratio is placed in a mortar, and the two substances are uniformly mixed to obtain a mixture. Next, the mixture is placed in a hydraulic press and pressed into a lump.

[0033] (2) A tungsten rod was used as the cathode and the lumpy mixture as the anode. The tungsten rod and the lumpy mixture were placed in an arc furnace with a distance of 1 mm between the two electrodes. The arc furnace was then vacuumed to 3 Pa, the DC arc discharge current was set to 12 A, and the arc was started after filling with argon gas at 70 kPa. The discharge time was set to 1 s, and the reactants on the inner wall of the reaction chamber were collected as nickel boride particles.

[0034] <Example 2> (1) Manufacturing of discharge anodes A mixture of boron powder and vanadium dioxide in a ratio of 8:1 was placed in a mortar and pestle, and the two substances were uniformly mixed to obtain the mixture. Next, the mixture was placed in a hydraulic press and pressed into a lump.

[0035] (2) A tungsten rod is used as the cathode and the lumpy mixture as the anode. The tungsten rod and the lumpy mixture are placed in the arc furnace with a distance of 2 mm between the electrodes. After the arc furnace is vacuumed to 2 Pa, the DC arc discharge current is set to 20 A, and the arc is started after filling with argon gas at 80 kPa. The discharge time is set to 10 s, and the reactants on the inner wall of the reaction chamber are collected as vanadium diboride particles.

[0036] <Example 3> (1) Manufacturing of discharge anodes A mixture of boron powder and titanium dioxide in a 4:1 ratio was placed in a mortar and pestle, and the two substances were uniformly mixed to obtain the mixture. Next, the mixture was placed in a hydraulic press and pressed into a lump.

[0037] (2) A tungsten rod is used as the cathode and the lumpy mixture as the anode. The tungsten rod and the lumpy mixture are placed in the arc furnace with a distance of 3 mm between the electrodes. After the arc furnace is vacuumed to 3 Pa, the DC arc discharge current is set to 50 A, and the arc is started after filling with argon gas at 40 kPa. The discharge time is set to 5 s, and the reactants on the inner wall of the reaction chamber are collected as titanium boride particles.

[0038] <Example 4> (1) Manufacturing of discharge anodes A mixture of boron powder and tricobalt tetroxide in a ratio of 10:1 was placed in a mortar and pestle, and the two substances were uniformly mixed to obtain a mixture. Next, the mixture was placed in a hydraulic press and pressed into a lump.

[0039] (2) A tungsten rod is used as the cathode and the lumpy mixture as the anode. The tungsten rod and the lumpy mixture are placed in the arc furnace with a distance of 1 mm between the two electrodes. The arc furnace is then vacuumed until the vacuum level reaches 3 Pa. After setting the DC arc discharge current to 12 A and filling with argon gas at 70 kPa, the arc is started. The discharge time is set to 30 s, and the reactants on the inner wall of the reaction chamber are collected as cobalt boride particles.

[0040] <Example 5> (1) Manufacturing of discharge anodes A mixture of boron powder and triiron tetroxide in a ratio of 10:1 was placed in a mortar and pestle, and the two substances were uniformly mixed to obtain the mixture. Next, the mixture was placed in a hydraulic press and pressed into a lump.

[0041] (2) A tungsten rod is used as the cathode and the lump mixture as the anode. The tungsten rod and lump mixture are placed in the arc furnace with a distance of 1 mm between the two electrodes. After the arc furnace is vacuumed to 3 Pa, the DC arc discharge current is set to 12 A, and the arc is started after filling with argon gas at 70 kPa. The discharge time is set to 5 s, and the reactants on the inner wall of the reaction chamber are collected as iron boride particles.

[0042] Furthermore, the transition metal boride prepared in Example 1 was analyzed. Figure 3 shows the X-ray diffraction pattern of the nickel boride particles prepared in Example 1. As shown in the measurement results, the diffraction peak of the product is in close agreement with the standard spectrum below. In other words, high-purity nickel boride particles were obtained by the DC arc method in Example 1. Furthermore, Figure 4 is a transmission electron microscope image of the nickel boride particles prepared in Example 1, and the planar spacing d of the nickel boride particles was measured to be 0.28 nm. This value corresponds to the (110) crystal plane of the nickel boride structure, indicating that the preparation of nickel boride was successful.

[0043] Furthermore, the vanadium diboride particles prepared in Example 2 were analyzed. Figure 5 shows the X-ray diffraction pattern of the vanadium diboride particles prepared in Example 2. As shown in the measurement results, the diffraction peak of the product is in close agreement with the standard spectrum below. In other words, high-purity vanadium diboride particles were obtained by the DC arc method in Example 2. Furthermore, Figure 6 is a transmission electron microscope image of the vanadium diboride particles prepared in Example 2, and the planar spacing d of the nickel boride particles was measured to be 0.12 nm. This value corresponds to the (201) crystal plane of the vanadium diboride structure, indicating that the preparation of vanadium diboride was successful.

[0044] Furthermore, the titanium diboride particles prepared in Example 3 were analyzed. Figure 7 shows the X-ray diffraction pattern of the titanium diboride particles prepared in Example 3. As shown in the measurement results, the diffraction peak of the product is in basic agreement with the standard spectrum below. In other words, high-purity titanium diboride particles were obtained by the DC arc method in Example 3. Furthermore, Figure 8 is a transmission electron microscope image of the titanium diboride particles prepared in Example 3, and the planar spacing d of the nickel boride particles was measured to be 0.12 nm. This value corresponds to the (201) crystal plane of the nickel boride structure, indicating that the production of titanium diboride was successful.

[0045] Furthermore, the titanium diboride particles prepared in Example 4 were analyzed. Here, Figure 9 shows the X-ray diffraction pattern of the cobalt boride particles prepared in Example 4. As shown in the detection results, the diffraction peak of the product is in essentially agreement with the standard spectrum below. In other words, high-purity cobalt boride particles were obtained by the DC arc method in Example 4. Furthermore, Figure 10 is a transmission electron microscope image of the cobalt boride particles prepared in Example 4, and the planar spacing d of the nickel boride particles was measured to be 0.12 nm. This value corresponds to the (111) crystal plane of the nickel boride structure, indicating that the preparation of cobalt boride was successful.

[0046] While the above embodiments represent preferred embodiments of the present invention, the embodiments of the present invention are not limited to these embodiments, and any other modifications, alterations, substitutions, combinations or simplifications made without departing from the spirit and principles of the present invention are all within the scope of protection of the present invention.

Claims

1. The steps include: preparing a tungsten rod and a lump mixture of boron powder and metal oxide, and placing the lump mixture and the tungsten rod in an arc furnace as the anode and cathode, respectively; A rapid method for producing a transition metal boride, comprising the steps of: evacuating the arc furnace to 3 Pa or less; then filling it with argon gas as a buffer gas; adjusting the pressure of the argon gas to 40 to 80 kPa; controlling the arc furnace to start the arc; igniting the lumpy mixture; and immediately controlling the arc furnace to close the arc, thereby allowing the lumpy mixture to undergo a continuous combustion reaction to obtain a transition metal boride, wherein the metal oxide is one of the following: tricobalt tetroxide, triiron tetroxide, titanium dioxide, and vanadium dioxide.

2. The rapid method for producing a transition metal boride according to claim 1, characterized in that the distance between the lump mixture and the tungsten rod in the arc furnace is 1 to 3 mm.

3. The rapid method for producing a transition metal boride according to claim 1, characterized in that the discharge current of the arc is 12 to 50 A and the discharge time of the arc is 1 to 30 s.

4. The rapid method for producing a transition metal boride according to claim 1, characterized in that the transition metal boride comprises one of cobalt boride, vanadium diboride, and titanium diboride.

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