A kind of preparation equipment and method of nano titanium nitride powder

Abstract

The present invention relates to the technical field of nano-metal powder manufacturing, and discloses a preparation device and method for nano-titanium nitride powder. The equipment includes a reactor, a titanium evaporation component arranged in the reactor, a nitrogen inlet opened at one end of the reactor, a powder discharge pipe opened at the other end of the reactor, a collector connected to the powder discharge pipe, and a powder collection port arranged at the bottom of the collector. The titanium evaporation component converts the titanium source into titanium vapor, and the ionized nitrogen at high temperature directly contacts the titanium vapor, thereby increasing the kinetics of the nitriding reaction and forming nano-scale titanium nitride powder. The titanium nitride powder enters the collector with the nitrogen gas flow, and the powder filter in the collector realizes gas-solid separation. The nano-scale titanium nitride powder is stably and continuously produced. The titanium nitride powder has a small particle size and a narrow particle size distribution range, and the product has high purity, high element conversion rate, and a simple process.

Description

Technical Field

[0001] The present invention relates to the technical field of metal powder manufacturing, and more particularly to a preparation device and method for nano titanium nitride powder. Background Art

[0002] Nano-titanium nitride powder is a new multifunctional cermet material with high hardness, a high melting point, good chemical stability, and high electrical and superconductivity. It is widely used in semiconductor devices, microelectronics, and porous ceramics. Nano-titanium nitride powder is generally required to have an average particle size below 100 nm, a narrow particle size distribution, and a well-defined spherical shape.

[0003] The current mainstream preparation methods for titanium nitride powder are direct nitridation, solvent thermal synthesis, thermal reduction, chemical vapor deposition and solid phase reaction synthesis. The direct nitridation method is a preparation method that uses metal titanium powder or TiH2 as raw material and reacts with nitrogen or nitride to produce TiN. U.S. Patent US5254359A discloses that titanium vapor is directly contacted with nitrogen and deposited on the substrate to form a coating. The defect of this method is that titanium nitride powder cannot be obtained. Another direct nitridation method is to press hydrogenated dehydrogenated titanium powder into a billet, and nitrogen contacts the titanium billet, but the transmission of nitrogen is hindered in the high-density titanium billet, resulting in insufficient reaction of the titanium nitride powder in the later stage, uneven particle size of the titanium nitride powder, and difficulty in obtaining nano-scale titanium nitride powder.

[0004] The solvothermal synthesis method uses sodium azide and titanium tetrachloride as raw materials and toluene as solvent to prepare cubic nano-titanium nitride powder. The powder is mostly flocculent, has serious agglomeration, unstable performance, and is easily oxidized to titanium dioxide at 600°C.

[0005] The thermal reduction method mainly uses titanium dioxide with an average particle size of 10μm as raw material and carbon powder as reducing agent. At high temperature, the carbon thermal reduction nitridation method easily forms a mixture of titanium nitride and titanium carbide, which is difficult to separate. In addition, the titanium nitride powder produced by this process has a high oxygen content. Removing oxygen from the powder requires several steps of purification operations, and the process is relatively cumbersome.

[0006] Chinese patent CN111620313A discloses a process for preparing nano-titanium nitride powder using chemical vapor deposition. The ammonia used in this process is highly irritating and corrosive, placing high safety requirements on equipment and operators. Secondly, elements such as Ar and H involved in the process do not participate in the reaction, which reduces the element conversion rate and increases the preparation cost. Finally, as the reaction proceeds, the nitrogen element in the mixed gas is consumed, which easily leads to uneven reaction.

[0007] Chinese patent CN109835875A uses a solid phase reaction synthesis method to synthesize titanium nitride powder. This method requires first mixing and submerging solid raw materials to achieve an ideal titanium-nitrogen ratio, and has high requirements on reaction temperature and reaction conditions, making it unsuitable for continuous production.

[0008] Based on the above situation, there is an urgent need in this field to develop a new technology that can stably and continuously produce nano-scale titanium nitride powder. Summary of the Invention

[0009] In order to solve the difficulty of stable and continuous production of nano-scale titanium nitride powder, the present application provides a preparation device and method for nano-scale titanium nitride powder. The nano-scale titanium nitride powder obtained by this method has a uniform reaction degree, a small particle size and a narrow particle size distribution range, a high product purity, a high element conversion rate, and a simple process.

[0010] In a first aspect, the present application provides an apparatus for preparing nano-titanium nitride powder, which adopts the following technical solution:

[0011] A device for preparing nano titanium nitride powder, comprising:

[0012] reactor;

[0013] a titanium evaporation assembly, located in the reactor, for generating titanium vapor;

[0014] a nitrogen inlet, located at one end of the reactor, wherein the nitrogen gas flow from the nitrogen inlet passes through the titanium evaporation assembly;

[0015] a powder discharge pipe, located at an end of the reactor away from the nitrogen inlet;

[0016] a collector, connected to the powder discharge pipe, wherein a powder filter is provided in the collector;

[0017] A powder collecting port is located at the bottom of the collector and collects nano-sized titanium nitride powder;

[0018] The gas reflux port is located at the top of the collector and is connected to the nitrogen inlet. The nitrogen gas flows through the powder filter element and refluxes to the nitrogen inlet.

[0019] By adopting the above technical solution, pure titanium is used as the reaction raw material, and the titanium evaporation component provides a high-temperature electric field, which can directly convert the titanium source into titanium vapor. Nitrogen replaces the air in the reactor and also serves as a reaction gas. Under the action of the high-temperature electric field, nitrogen becomes an ionized state with strong chemical activity and directly contacts the titanium vapor to form nano-scale titanium nitride powder. No pollutants and by-products are generated during the reaction process. Nano-scale titanium nitride powder is transported to the powder discharge pipe along with nitrogen, and then enters the collector. Nano-scale titanium nitride powder flows through the powder filter and flows out of the powder collection port. The entrained nitrogen is filtered through the powder filter and re-enters the reactor from the gas reflux port. Nano-titanium nitride powder can react and produce continuously.

[0020] Furthermore, the titanium evaporation assembly includes an arc generator, a feeding pipe and a conductive crucible, the conductive crucible is fixed at the bottom of the reactor, the feeding pipe is arranged at the top of the reactor, the bottom of the feeding pipe is located above the conductive crucible, and the arc generating end of the arc generator is aligned with the inside of the conductive crucible.

[0021] By adopting the above technical solution, titanium powder can directly enter the conductive crucible through the feeding pipe, and the arc generating end of the arc generator excites a high-temperature arc. The high-temperature arc causes the titanium powder raw material in the conductive crucible to directly evaporate into titanium vapor. The ionized nitrogen and titanium vapor can directly react with nitridation to obtain nano-titanium nitride powder, which facilitates the continuous production of titanium nitride.

[0022] Furthermore, the titanium evaporation components are provided in a plurality of groups, and the plurality of groups of titanium evaporation components are distributed in an array.

[0023] By adopting the above technical solution, a plurality of titanium evaporation components are arranged in a matrix or annular array on a horizontal plane, so that nitrogen can fully contact with titanium vapor, thereby improving reaction efficiency.

[0024] Furthermore, the arc generating end of the arc generator is lower than the center height of the nitrogen inlet.

[0025] By adopting the above technical solution, the lateral nitrogen gas flow is not likely to disturb the arc.

[0026] Furthermore, an air flow channel is arranged around the arc generator.

[0027] By adopting this technical solution, nitrogen is ejected from the airflow channel, protecting the arc-generating end from nitrogen and preventing titanium nitride powder from adhering to the arc-generating end. The airflow channel forms a protective barrier, preventing the nitrogen inlet from negatively impacting arc stability.

[0028] Furthermore, the reactor is in a sealed state, an air pressure detector is provided in the reactor, a supplementary nitrogen source is connected to the outside of the reactor, and the supplementary nitrogen source is communicated with the nitrogen inlet.

[0029] By adopting the above technical solution, since the reactor is sealed internally, only nitrogen is present in the reactor, and the air pressure within the reactor is the nitrogen pressure. The present application can determine the nitrogen remaining in the reactor based on the displayed reading of the pressure detector. When the nitrogen pressure in the system falls below the set value, the opening of the supplementary nitrogen source is adjusted to adjust the nitrogen replenishment amount in the reactor to maintain the system pressure, thereby simplifying process monitoring and control.

[0030] Furthermore, a circulation fan is connected to the outside of the reactor, the air inlet of the circulation fan is communicated with the gas reflux port, and the air outlet of the circulation fan is communicated with the nitrogen inlet.

[0031] By adopting the above technical solution, the circulating fan is connected to the nitrogen replenishment pipeline, and the nitrogen transported into the nitrogen replenishment pipeline is mixed with the reflux circulating nitrogen in the circulating fan, and then re-enters the reactor to replenish the nitrogen concentration in the reactor.

[0032] Furthermore, a cooling jacket and a cooling air flow input pipe are sequentially provided on the outer shell of the powder discharge pipe, and the cooling air flow input pipe extends into the powder discharge pipe, and the flow rate of the cooling air flow input pipe is lower than the nitrogen flow rate at the powder discharge pipe.

[0033] By adopting the above technical solution, the cooling jacket generally discharges the airflow in the powder discharge pipe by liquid cooling. At the same time, the cooled airflow exchanges heat with the nitrogen mixed with titanium nitride powder through the cooling airflow input pipe, which helps to further cool the temperature of the titanium nitride powder, which can not only facilitate the rapid cooling of the titanium nitride powder, but also extend the service life of the collector.

[0034] Furthermore, the powder filter is provided with several.

[0035] By adopting the above technical solution, multiple powder filters intercept the nano-titanium nitride powder, preventing the nano-scale titanium nitride powder from flowing back from the gas reflux port, which would increase the particle size of the titanium nitride powder.

[0036] Furthermore, an air outlet is provided at the powder discharge pipe.

[0037] By adopting the above technical solution, since the temperature inside the reactor is much higher than that outside, the air flow at the outlet is discharged to the outside, forming a unidirectional airflow at the outlet, and the air pressure at the outlet is reduced, guiding the nitrogen in the reactor to flow toward the powder discharge pipe, thereby accelerating the collection of nano-scale titanium nitride powder.

[0038] In a second aspect, the present application provides a method for preparing nano-titanium nitride powder, which adopts the following technical solution:

[0039] A method for preparing nano titanium nitride powder, implemented in the aforementioned nano titanium nitride powder preparation equipment, comprises the following steps:

[0040] Open the nitrogen inlet to replace the air in the reactor and the collector;

[0041] Starting the titanium evaporation assembly and simultaneously opening the powder collection port and the gas reflux port;

[0042] Collect nano-titanium nitride powder.

[0043] By adopting the above technical solution, the method has simple implementation steps, is easy to produce, and reduces the difficulty of process monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a schematic cross-sectional view of a device for preparing nano-titanium nitride powder disclosed in Example 1.

[0045] Figure 2 This is a schematic diagram of the cross-sectional structure of an arc generator in the equipment for preparing nano-titanium nitride powder disclosed in Example 1.

[0046] Figure 3 This is a schematic diagram of a rectangular array arrangement of titanium evaporation components in a nano-titanium nitride powder preparation device disclosed in Example 1.

[0047] Figure 4 This is a schematic diagram of the annular array arrangement of titanium evaporation components in the equipment for preparing nano-titanium nitride powder disclosed in Example 1.

[0048] Figure 5 This is the SEM image of the nano-titanium nitride powder produced in Example 1.

[0049] Figure 6 This is the XRD pattern of the nano-titanium nitride powder produced in Example 1.

[0050] In the accompanying drawings:

[0051] 1. Reactor; 11. Anode base; 12. Air pressure detector; 2. Titanium evaporation assembly; 21. Arc generator; 211. Air flow channel; 22. Feeding pipe; 23. Conductive crucible; 3. Nitrogen inlet; 4. Powder discharge pipe; 41. Cooling air flow input pipe; 42. Cooling jacket; 43. Gas outlet; 5. Collector; 51. Powder filter; 52. Powder collection port; 53. Gas reflux port; 6. Circulation fan; 7. Nitrogen supplement source. DETAILED DESCRIPTION

[0052] Example 1

[0053] Figure 1 This is a schematic cross-sectional view of a device for preparing nano-titanium nitride powder disclosed in Example 1. Figure 1 , a preparation device for nano titanium nitride powder, includes a reactor 1. A titanium evaporation component 2 is arranged inside the reactor 1, and the titanium evaporation component 2 includes an arc generator 21, a feeding pipe 22 and a conductive crucible 23. An anode base 11 is fixedly connected to the bottom of the reactor 1, and the conductive crucible 23 is fixed on the anode base 11. The feeding end of the feeding pipe 22 is located above the conductive crucible 23, and titanium powder enters the conductive crucible 23 from the feeding pipe 22. The arc generator 21 acts as an arc cathode, and the arc generating end of the arc generator 21 releases a high-temperature arc, which causes the titanium powder in the conductive crucible 23 to evaporate rapidly to form titanium vapor.

[0054] See also Figure 1 A nitrogen inlet 3 is provided at one end of the reactor 1. Nitrogen replaces the air within the reactor 1, reducing the gas-phase oxygen content within the reactor 1 to less than 0.01 vol%. Nitrogen serves as both a protective gas and a reactive gas. The nitrogen flow rate at the nitrogen inlet 3 is controlled at 20 to 500 SLPM, and the pressure within the reactor 1 is maintained at 5 to 10 kPa. The center height of the nitrogen inlet 3 is higher than the arc generator 21 to prevent the nitrogen flow from disrupting the arc. Simultaneously, the nitrogen flow is delivered directly to the titanium vapor. Due to the high-temperature electric field, the nitrogen becomes a highly chemically active ionized state, directly contacting the titanium vapor. This increases the kinetics of the nitridation reaction and forms nano-sized titanium nitride powder. A powder discharge pipe 4 is provided at the other end of the reactor 1. The nano-sized titanium nitride powder is discharged from the reactor 1 through the powder discharge pipe 4 along with the nitrogen.

[0055] See also Figure 2 The arc generator 21 is surrounded by an airflow channel 211, which emits nitrogen. This nitrogen flow protects the discharge tip of the arc generator 21, preventing molten titanium from adhering to it. The airflow channel 211 also forms a protective barrier, preventing the nitrogen flow from the inlet 3 from negatively impacting arc stability. The arc generator 21 is set to a current of 200-300A, and the height of the arc generator 21 is adjusted to maintain a voltage of 50V.

[0056] See also Figure 1The outer wall of the powder discharge pipe 4 is sequentially covered with a cooling air flow input pipe 41 and a cooling jacket 42. The cooling jacket 42 adopts liquid cooling, generally using water as a coolant. The cooling jacket 42 cools the nitrogen and nano-titanium nitride powder in the powder discharge pipe 4, so that the nitrogen and nano-titanium nitride powder discharged from the reactor 1 are cooled. The air inlet end of the cooling air flow input pipe 41 is externally connected to a nitrogen gas source, and the air outlet end of the cooling air flow input pipe 41 extends into the powder discharge pipe 4. The nitrogen temperature of the cooling air flow input pipe 41 is relatively low, and it can exchange heat with the high-temperature nitrogen in the powder discharge pipe 4, which helps to further cool the temperature of the titanium nitride powder, which can not only facilitate the rapid cooling of the titanium nitride powder, but also extend the service life of the collector 5. At the same time, in order to prevent the cooling air flow from disturbing the discharge of the nano-titanium nitride powder, the flow rate of the cooling air flow input pipe 41 is controlled to be lower than the nitrogen flow rate at the powder discharge pipe 4. An air outlet 43 is provided at the powder discharge pipe 4. Since the temperature inside the reactor 1 is much higher than the outside, the air flow at the air outlet 43 is discharged to the outside, forming a unidirectional airflow at the air outlet 43. The air pressure at the air outlet 43 is reduced, guiding the nitrogen in the reactor 1 to flow toward the powder discharge pipe 4, thereby accelerating the collection of nano-scale titanium nitride powder.

[0057] See also Figure 1 The powder discharge end of the powder discharge pipe 4 is connected to a collector 5, and several groups of powder filters 51 are arranged in the collector 5. The powder filter 51 can be made of a porous ceramic filter element. The mesh aperture of the powder filter 51 is ≤100nm. The powder filter 51 can intercept a large amount of nano-titanium nitride powder. Multiple powder filters 51 can efficiently intercept titanium nitride powder and prevent nano-scale titanium nitride powder from flowing back into the reactor 1, resulting in an increase in the particle size of the nano-titanium nitride powder. A vibration or back-blowing device (not shown in the figure) can be installed on the top of the powder filter 51. The vibration or back-blowing device can enable the powder filter 51 to discharge the titanium nitride powder mixed in the filter pores. A powder collection port 52 is provided at the bottom of the collector 5, and the separated nano-titanium nitride powder is discharged from the powder collection port 52.

[0058] See also Figure 1 A gas reflux port 53 is located at the top of the collector 5. Nitrogen separated by the powder filter 51 is discharged from the gas reflux port 53. The gas reflux port 53 is connected to the circulation fan 6. The air inlet of the circulation fan 6 is connected to the gas reflux port 53, and the air supply main of the circulation fan 6 is connected to the nitrogen inlet 3. Unreacted nitrogen can be recycled into the reactor 1, saving energy. At the same time, the air supply branch of the circulation fan 6 is connected to the feeding pipe 22 to maintain the nitrogen atmosphere in the reactor 1.

[0059] See also Figure 1The reactor 1 is also connected to a supplemental nitrogen source 7 externally, which is in communication with the nitrogen inlet 3. The connections between the reactor 1 and the various components are sealed. A pressure gauge 12 is provided within the reactor 1. Since only nitrogen is present within the reactor 1, the pressure within the reactor 1 is the nitrogen pressure. Nitrogen consumption can be reflected by changes in the reading of the pressure gauge 12. When the nitrogen pressure within the system falls below the set value, the opening of the supplemental nitrogen source 7 is adjusted to fill the system with nitrogen to maintain a stable system pressure, simplifying process monitoring and control.

[0060] See also Figure 3 and Figure 4 Several titanium evaporation components 2 are installed in the reactor 1. The titanium evaporation components 2 can be distributed in a rectangular array or a ring array in the same horizontal direction. Figure 3 This is a top view of the rectangular array arrangement of the titanium evaporation components 2 in Example 1. Figure 4 This is a top view of the annular array arrangement of titanium evaporation assemblies 2 in Example 1. In this embodiment, the number of titanium evaporation assemblies 2 is generally set to 4, and multiple titanium evaporation assemblies 2 work together to improve the production efficiency of nano-scale titanium nitride powder.

[0061] The specific working method of this embodiment is as follows:

[0062] Turn on the circulating fan 6 and the nitrogen inlet 3, adjust the nitrogen flow rate, empty the air in the reactor 1 and the collector 5, and maintain the air pressure in the reactor 1 within the set pressure range;

[0063] Open the feeding pipe 22 and add the titanium source, which falls into the conductive crucible 23;

[0064] Turn on the arc generator 21 and simultaneously open the powder collection port 52, the gas return port 53, the cooling jacket 42, the cooling air flow input pipe 41 and the gas outlet 43;

[0065] Adjust the gas flow rate of nitrogen inlet 3;

[0066] Collect nano-titanium nitride powder at the powder collection port.

[0067] Figure 5 This is the SEM image of the nano-titanium nitride powder produced in Example 1. Figure 5 The titanium nitride powder can be nanometer-sized. Figure 6 This is the XRD image of the nano titanium nitride powder produced in this embodiment 1. Figure 6 It can be seen that the appearance and crystal form of the titanium nitride powder are both cubic. The titanium nitride powder produced in Example 1 was sampled and the titanium nitride content was measured to be 94.66wt%.

[0068] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] Furthermore, the above-described embodiments merely represent several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent. It should be noted that a person of ordinary skill in the art can make a number of variations and improvements without departing from the concept of the present invention, and these variations and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be based on the appended claims.

Claims

1. A method for preparing nano titanium nitride powder, characterized in that: The method comprises the following steps: replacing the air in the reactor and the collector with nitrogen; starting the titanium evaporation component, evaporating the titanium powder to form titanium vapor, and sending the nitrogen gas directly to the titanium vapor, so that the nitrogen gas becomes an ionized state with strong chemical activity and directly contacts the titanium vapor to form nano-scale titanium nitride powder; synchronously opening the powder collection port and the gas reflux port, allowing the unreacted nitrogen gas to re-enter the reactor for recycling and maintain the nitrogen atmosphere in the reactor. The air pressure in the reactor is the nitrogen air pressure, and the nitrogen consumption can be reflected by the change in the reading of the air pressure detector; collecting the nano-titanium nitride powder; the preparation method of the nano-titanium nitride powder is carried out in the nano-titanium nitride powder preparation equipment; the nano-titanium nitride powder preparation equipment comprises a reactor (1); A titanium evaporation assembly (2) is located in the reactor (1) and is used to generate titanium vapor; the titanium evaporation assembly (2) includes an arc generator (21), a feeding pipe (22) and a conductive crucible (23), the conductive crucible (23) is fixed to the bottom of the reactor (1), the feeding pipe (22) is arranged on the top of the reactor (1), the bottom of the feeding pipe (22) is located above the conductive crucible (23), and the arc generating end of the arc generator (21) is aligned with the inside of the conductive crucible (23); a nitrogen inlet (3) is located at one end of the reactor (1), the nitrogen gas flow of the nitrogen inlet (3) passes through the titanium evaporation assembly (2) and the arc generating end of the arc generator (21) is lower than the center height of the nitrogen inlet (3); the reactor The reactor (1) is in a sealed state. A pressure detector (12) is provided in the reactor (1). A supplementary nitrogen source (7) is connected to the outside of the reactor (1), and the supplementary nitrogen source (7) is in communication with the nitrogen inlet (3). A circulating fan (6) is connected to the outside of the reactor (1), an air inlet of the circulating fan (6) is in communication with the gas reflux port (53), and an air outlet (43) of the circulating fan (6) is in communication with the nitrogen inlet (3). An air supply branch of the circulating fan (6) is in communication with a feeding pipe (22). A powder discharge pipe (4) is located at one end of the reactor (1) away from the nitrogen inlet (3). A collector (5) is in communication with the powder discharge pipe (4), and a powder filter (51) is provided in the collector (5). A powder collecting port (52) is located at the bottom of the collector (5) and collects nano-sized titanium nitride powder; a gas reflux port (53) is located at the top of the collector (5) and is connected to the nitrogen inlet (3); nitrogen flows through the powder filter (51) and refluxes to the nitrogen inlet (3).

2. The method for preparing nano titanium nitride powder according to claim 1, wherein: The titanium evaporation components (2) of the reactor (1) are provided in a plurality of groups, and the plurality of groups of titanium evaporation components (2) are distributed in an array.

3. The method for preparing nano titanium nitride powder according to claim 1, wherein: An air flow channel (211) is arranged around the arc generator (21).

4. The method for preparing nano titanium nitride powder according to claim 1, wherein: A cooling jacket (42) and a cooling air flow input pipe (41) are sequentially provided on the outer shell of the powder discharge pipe (4), and the cooling air flow input pipe (41) extends into the powder discharge pipe (4), and the flow rate of the cooling air flow input pipe (41) is lower than the nitrogen flow rate at the powder discharge pipe (4).

5. The method for preparing nano titanium nitride powder according to claim 1, wherein: The powder discharge pipe (4) is provided with an air outlet (43).

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