Tungsten slurry atomizing nozzle and tungsten powder manufacturing method

Abstract

The invention provides a tungsten slurry atomizing nozzle. The tungsten slurry atomizing nozzle comprises a plurality of channels and nozzle openings, wherein the channels are coaxially arranged in the nozzle; the nozzle openings are formed in the tail ends of all the channels; the channels comprise at least one feeding channel and at least two rotational flow channels, tungsten slurry is introduced into the feeding channels, and argon is introduced into the rotational flow channels; and the argon shearing force formed by the rotational flow channel at the nozzle opening is used for crushing the tungsten slurry liquid drops sprayed out of the feeding channel, so that the liquid drops with the target particle size are obtained. Tungsten slurry is crushed through argon shearing force generated by all the rotational flow channels of the nozzle, the particle size of atomized liquid drops of the tungsten slurry is controlled to be about 500 nanometers, meanwhile, the tungsten slurry can be rotationally sprayed out, and therefore a large atomization area is formed, and the tungsten slurry can be highly dispersed and atomized; after the water in the liquid drops is evaporated, the irregular tungsten powder in the liquid drops is agglomerated together to form the spherical powder with the particle size of 0.5-5 microns, the spherical powder is uniformly dispersed, and the yield is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor materials, and in particular to a tungsten slurry atomizing nozzle and a method for manufacturing tungsten powder. Background Art

[0002] In the semiconductor industry, tungsten powder is an important high melting point material and plays an irreplaceable role. However, due to the high melting point of tungsten powder, when the particle size is small, the molecular force between tungsten powders plays a dominant role, and agglomeration is easy to occur, making it difficult to be used in industrial applications. Even after spheroidization by plasma and rotating electrode method, problems such as blockage and agglomeration still occur in the range of 0.5 to 5 microns, and this particle size range is currently the urgently needed tungsten powder use range in the semiconductor field.

[0003] Currently, for non-spherical tungsten powder, slurry is used to solve the problem of tungsten powder dispersion and fluidity. However, compared with spherical tungsten powder, it still has the problems of low yield and uneven product surface. Summary of the invention

[0004] Purpose of the invention: In view of the problems existing in the prior art, the present invention provides a tungsten slurry atomizing nozzle and a tungsten powder manufacturing method to form evenly dispersed spherical tungsten powder particles.

[0005] Technical solution: A tungsten slurry atomizing nozzle according to the present invention comprises a plurality of channels coaxially arranged in the nozzle and nozzle openings constructed at the ends of all the channels; The channel includes at least one feed channel and at least two cyclone channels, the feed channel is fed with tungsten slurry, and the cyclone channel is fed with argon gas; The argon shear force formed by the swirl channel at the nozzle port breaks up the tungsten slurry droplets sprayed from the feed channel to obtain droplets of target particle size.

[0006] Further, the feed channel is set as the first channel, and the swirl channel is set as the second channel and the third channel: The first channel runs through the axial direction of the nozzle; The second channel has a ring-shaped cross section and is sleeved on the outer periphery of the first channel; The third channel has a ring-shaped cross section and is sleeved on the outer periphery of the second channel.

[0007] Furthermore, the end position of the feed channel is adjustable relative to the end position of the swirl channel.

[0008] Furthermore, there is a cooling water channel surrounding all the channels in the nozzle, and the cooling water channel is spiral.

[0009] Furthermore, there is a gap between adjacent spiral circumferential pipes of the cooling water channel.

[0010] Furthermore, the target particle size is 500 nanometers.

[0011] Furthermore, the tungsten slurry atomizing nozzle is made of a high-hardness material, including ceramic or tungsten carbide.

[0012] A method for manufacturing tungsten powder based on a tungsten slurry atomizing nozzle comprises the following steps: S1. Mix irregular tungsten powder of 100-500 nanometers with water, and coat the surface of the tungsten powder particles with inorganic compounds through ultrasonic waves; S2. Introduce plasma torch argon gas into the swirl channel of the tungsten slurry atomizing nozzle for ignition. When the power gradually increases to the specified power, open the valve; S3, passing the tungsten slurry prepared in step S1 into the feed channel, and at the nozzle port, the argon shear force formed by the swirl channel breaks up the tungsten slurry droplets sprayed from the feed channel to obtain droplets of target particle size; S4. The liquid droplets obtained in step S3 are sprayed along with the high-temperature plasma, melted into spherical liquid by gasification, and formed into spherical tungsten powder after rapid cooling.

[0013] Furthermore, in step S1, the mixing ratio of tungsten powder to water is 1:5-3:1, and the inorganic compound includes tartaric acid or a hyperdispersant.

[0014] Further, in step S3, tungsten slurry is pumped into the feed channel at a pressure value of 0.3-1.0 MPaG.

[0015] Beneficial effects: The present invention uses the argon shear force generated by each swirl channel of the nozzle to break up the tungsten slurry, and controls the particle size of the atomized droplets to be about 500 nanometers. At the same time, the tungsten slurry can be rotated and sprayed out to form a larger atomization area, which can make the tungsten slurry highly dispersed and atomized; when the water in the droplets evaporates, the irregular tungsten powder in the droplets will agglomerate together to form spherical powder with a particle size of 0.5 to 5 microns. The spherical powder is evenly dispersed, and the yield rate is effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of the nozzle of the present invention; Figure 2 is a structural schematic diagram of the first casing; Figure 3 is a schematic diagram of the structure of the second casing; Figure 4 It is a schematic diagram of the structure of the third casing. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the embodiments.

[0018] In order to make the purpose and implementation of the present application clearer, the exemplary implementation of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, rather than all of the embodiments. It should be noted that the brief description of the terms in this application is only for the convenience of understanding the implementation described below, and is not intended to limit the implementation of the present application. Unless otherwise specified, these terms should be understood according to their common and usual meanings.

[0019] Generally, tungsten powder with a particle size of less than 5mm cannot enter the plasma torch smoothly, and is prone to blockage in the powder feeding channel. Or when entering the plasma torch, the tungsten powder agglomerates to form larger agglomerates, which ultimately makes it impossible for the tungsten powder to be dispersed into the high-temperature plasma.

[0020] Based on this, the present invention proposes a tungsten slurry atomizing nozzle, such as Figure 1 As shown, it includes multiple coaxial channels arranged in the nozzle and nozzle openings constructed at the ends of all the channels, at least two of the channels are used to introduce argon gas, and at least one channel is used to introduce tungsten slurry; at the nozzle opening, the argon shear force formed by at least two channels breaks the tungsten slurry droplets ejected from at least one channel to obtain droplets of target particle size. The target particle size here is defined as 500 nanometers.

[0021] The channel for introducing tungsten slurry is called the first channel 1, and the channels for introducing argon are called the second channel 2 and the third channel 3. The first channel 1, the second channel 2 and the third channel 3 are coaxially sleeved in order from the inside to the outside, and the end outlets of all channels are unified as nozzle openings. Specifically, the first channel 1 is an axial channel that passes through the nozzle, and the cross section is circular; the cross sections of the second channel 2 and the third channel 3 are annular, the second channel 2 is sleeved on the outer periphery of the first channel 1, and the third channel 3 is sleeved on the outer periphery of the second channel 2.

[0022] In some embodiments, the first channel 1, the second channel 2 and the third channel 3 may be implemented by three coaxially stacked hollow sleeves. Figures 2~4As shown, a first sleeve 101 is arranged along the axis of the nozzle, and the first sleeve 101 is provided with a through hole, which can be used as a first channel 1. Secondly, a second sleeve 201 is coaxially arranged on the outer periphery of the first sleeve 101. Since the second sleeve 201 also has a through hole, the space between the outer wall of the first sleeve 101 and the inner wall of the second sleeve 201 can form a second channel 2. Similarly, the third channel 3 can be realized by a third sleeve 301 sleeved outside the second sleeve 201, and the third sleeve 301 is also the outer wall of the nozzle. With this structural design, the tungsten slurry channel can be coaxial with the inner ring argon gas and the outer ring argon gas, and there is an angle between the cyclonic directions of the inner and outer ring argon gases rushing out of the nozzle mouth, and a shear force is formed at the outlet, thereby breaking the tungsten slurry droplets to obtain droplets of target particle size.

[0023] In some embodiments, the first channel 1 is retractable, and the atomization effect can be changed by adjusting the relative position of its terminal outlet and the outlets of other channels to obtain the desired target particle size of the tungsten slurry droplets.

[0024] In some embodiments, there is a spiral cooling water channel 4 surrounding all channels in the nozzle, such as Figure 1 As shown, the cooling water channel 4 is a spiral pipe that is arranged around the third sleeve 301, and therefore surrounds the outer periphery of the third channel 3 in structure. The inlet 401 and the outlet 402 of the cooling water channel 4 extend out of the nozzle to facilitate the circulation of cooling water in the cooling water channel 4. In order to prevent the cooling water of the adjacent pipes in the spiral cooling water channel 4 from generating heat transfer and affecting the cooling effect, there is a gap between the adjacent spiral circumferential pipes of the cooling water channel 4.

[0025] Furthermore, the tungsten slurry atomizing nozzle is made of high hardness materials, including ceramic or tungsten carbide, which is more wear-resistant to ensure the normal operation of the nozzle for a long time.

[0026] A method for manufacturing tungsten powder based on a tungsten slurry atomizing nozzle comprises the following steps: S1. Select irregular tungsten powder of 100-500 nanometers as raw material, add high-purity water, mix in a certain proportion, add inorganic compounds such as tartaric acid, superdispersant, etc. to physically coat the surface, place it in an ultrasonic pool, and fully disperse it through high-frequency vibration, so that the inorganic compound fully wraps the tungsten powder particles, thereby weakening the agglomeration between the particles.

[0027] The mixing ratio of irregular tungsten powder and water is 1:5-3:1. In this embodiment, 2:1 can be used as the mixing ratio. Conventional commercially available hyperdispersants can be used. The concentrations of inorganic compounds and hyperdispersants are not limited here. As long as the inorganic compounds can be fully diffused to be wrapped by the tungsten powder, the concentration here can be determined according to the wrapping effect. Complete coating can produce the best effect of avoiding agglomeration.

[0028] S2. After ionization, argon gas has conductivity. As the airflow increases, a certain length of plasma will be blown out. The greater the plasma airflow, the longer the plasma flame. After the plasma torch argon and cooling gas are introduced, ignition is performed. When the power gradually increases to the specified power, the switch for introducing the slurry is turned on.

[0029] Ignition refers to turning on the RF power supply. The high-frequency induction current generated by the RF power supply ionizes the argon gas in the torch tube and energizes it, thereby generating high temperature. The specified power here generally refers to a rise to more than 30kw. The specific value needs to be determined according to the process, that is, the specified power is determined according to the combustion process, such as the amount of slurry introduced, temperature, pressure and other factors.

[0030] S3. After sufficient mixing, the uniform tungsten powder slurry is pumped into the first channel 1 of the nozzle through a water tungsten slurry pump at a certain pressure (0.3~1.0) MPaG. The pumping speed is determined by the technical indicators that can be achieved after the tungsten slurry is sprayed out, such as the spheroidization rate, water content, and impurity content of the tungsten powder. After the above indicators are determined, the pumping speed of the tungsten slurry can be controlled by pressure.

[0031] By adjusting the length of the first channel 1, the argon cyclone gas ejected from the second channel 2 and the third channel 3 forms a shear force at the end of the first channel 1, which breaks up the tungsten slurry after crossing, forming droplets of about 500 nanometers, which are dispersed and sprayed.

[0032] S4. Atomized droplets are ejected into the reaction chamber along with high-temperature plasma. At a high temperature of 10,000°C, the water in the droplets is rapidly vaporized and melted to form spherical metal droplets, which can be quickly cooled by high-pressure argon gas in the cooling chamber to form spherical powder of about 500 nanometers.

[0033] S5. The collection tank at the bottom of the reaction chamber collects 500 nanometer spherical powder particles; smaller powders will enter the lower-level cyclone dust collector with the airflow, and after dust removal, they will be captured and collected in the fine powder particle tank.

[0034] The manufacturing method of the present invention liquefies tungsten powder and water, and changes the original tungsten powder particle feeding method into a liquid powder feeding method, which effectively reduces the blockage caused by powder fluidity, and the liquid slurry can also increase the service life of the equipment. At the same time, because the temperature in the plasma is very high, exceeding 10,000°C, when the melting point of the powder is low, or the particles are too fine (0.5-5 microns), the fine powder will be quickly vaporized when the powder passes through the plasma, and will form nanopowders <500nm after rapid cooling downstream, and the spherical powder yield in the target range is very low. In the present invention, by adding water to form a slurry, the residence time of the fine powder in the plasma can be effectively increased, which helps to better control the process of spherical powder formation.

[0035] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims

1. A tungsten slurry atomizing nozzle, characterized in that: It includes a plurality of channels coaxially arranged in the nozzle and a nozzle opening constructed at the ends of all the channels; The channel includes at least one feed channel and at least two cyclone channels, the feed channel is fed with tungsten slurry, and the cyclone channel is fed with argon gas; The argon shear force formed by the swirl channel at the nozzle port breaks up the tungsten slurry droplets sprayed from the feed channel to obtain droplets of target particle size.

2. The tungsten slurry atomizing nozzle according to claim 1, characterized in that: The feed channel is set as the first channel, and the swirl channel is set as the second channel and the third channel: The first channel runs through the axial direction of the nozzle; The second channel has a ring-shaped cross section and is sleeved on the outer periphery of the first channel; The third channel has a ring-shaped cross section and is sleeved on the outer periphery of the second channel.

3. The tungsten slurry atomizing nozzle according to claim 1, characterized in that: The end position of the feed channel is adjustable relative to the end position of the swirl channel.

4. The tungsten slurry atomizing nozzle according to claim 1, characterized in that: There is a cooling water channel surrounding all the channels in the nozzle, and the cooling water channel is spiral.

5. The tungsten slurry atomizing nozzle according to claim 4, characterized in that: There is a gap between adjacent spiral circumferential pipes of the cooling water channel.

6. The tungsten slurry atomizing nozzle according to claim 1, characterized in that: The target particle size is 500 nanometers.

7. The tungsten slurry atomizing nozzle according to claim 1, characterized in that: The tungsten slurry atomizing nozzle is made of a high-hardness material, including ceramic or tungsten carbide.

8. A method for manufacturing tungsten powder based on a tungsten slurry atomizing nozzle, characterized in that: The following steps are involved: S1. Mix irregular tungsten powder of 100-500 nanometers with water, and coat the surface of the tungsten powder particles with inorganic compounds through ultrasonic waves; S2. Introduce plasma torch argon gas into the swirl channel of the tungsten slurry atomizing nozzle for ignition. When the power gradually increases to the specified power, open the valve; S3, passing the tungsten slurry prepared in step S1 into the feed channel, and at the nozzle port, the argon shear force formed by the swirl channel breaks up the tungsten slurry droplets sprayed from the feed channel to obtain droplets of target particle size; S4. The liquid droplets obtained in step S3 are sprayed along with the high-temperature plasma, melted into spherical liquid by gasification, and formed into spherical tungsten powder after rapid cooling.

9. The method for producing tungsten powder based on a tungsten slurry atomizing nozzle according to claim 8, characterized in that: In step S1, the mixing ratio of tungsten powder to water is 1:5-3:1, and the inorganic compound includes tartaric acid or a hyperdispersant.

10. The method for producing tungsten powder based on a tungsten slurry atomizing nozzle according to claim 8, characterized in that: Step S3: The tungsten slurry is pumped into the feed channel at a pressure of 0.3-1.0 MPaG.

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