CN113263181A - Method for efficiently preparing spherical metal microparticles with uniform and controllable particle size and preparation device thereof - Google Patents
Method for efficiently preparing spherical metal microparticles with uniform and controllable particle size and preparation device thereof Download PDFInfo
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- CN113263181A CN113263181A CN202110476958.8A CN202110476958A CN113263181A CN 113263181 A CN113263181 A CN 113263181A CN 202110476958 A CN202110476958 A CN 202110476958A CN 113263181 A CN113263181 A CN 113263181A
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- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
- B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
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- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
- B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
- B22F2009/0816—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying by casting with pressure or pulsating pressure on the metal bath
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Abstract
The invention provides a method and a device for preparing micron-sized spherical metal microparticles with uniform and controllable particle sizes, wherein the preparation method comprises the following steps: at vacuum degree lower than 10‑3Under the condition of Pa, melting the metal in the crucible into a liquid state; protective gas is introduced into the crucible and the vacuum chamber, a constant forward pressure difference is formed between the crucible and the vacuum chamber under the control of a differential pressure controller, meanwhile, a certain pulse signal is applied to the piezoelectric ceramic to drive the transmission rod below to generate micro displacement, the pulse signal acts on a melt near the micropore at the bottom of the crucible to enable a certain volume of micro liquid to be ejected from the micropore at the bottom of the crucible, and after metal liquid drops are formed, the metal liquid drops are subjected to radiation heat exchange and convection heat exchange with the surrounding environment in the falling process and are rapidly solidified to form spherical metal microparticles. The particles prepared by the method have high sphericity, consistent thermal history, controllable particle size and high preparation efficiency, and the problem of preparation of micro particles in the prior art is solvedThe sphericity of the meter-level particles is low, the particle size distribution is uneven, and the like.
Description
Technical Field
The invention relates to the technical field of spherical metal particle preparation, in particular to a method for efficiently preparing micron-sized spherical metal microparticles with uniform and controllable particle sizes and a preparation device thereof.
Background
The micron-sized uniform spherical metal particles are special spherical powder particles with the size ranging from nanometer to millimeter and uniform particle size. The upper limit of mechanical processing is supported, the lower limit of nano processing is supported, and the method has the advantages of having no alternative status and function in the aspects of size connection and performance requirements, and is widely applied to the fields of 3D electronic packaging, additive manufacturing based on a droplet forming technology and the like.
In the 3D electronic packaging technology, the multilayer packaging needs to be subjected to multiple thermal processes, and if a common solder ball is used, remelting occurs after heating for multiple times, and in addition, the dead weight of the upper chip often causes a crushing phenomenon, which leads to a short circuit of the chip or affects the flatness of the chip, thereby greatly damaging the quality of the product. To solve this problem, solder balls of core (copper)/shell (solder) structure have been produced.
At present, the most key technical bottleneck in the preparation of the core (copper)/shell (soldering tin) structure soldering tin ball is the preparation of the copper core with high-precision grain diameter, and the preparation method is not completely established.
In the droplet formation technology, uniform and stable preparation and high-precision deposition of metal droplets are important prerequisites for practical application of droplet formation technology. In order to ensure the precision and various performances of the prepared product, how to continuously and stably prepare uniform micro-droplets according to needs becomes a core problem of the technology.
The methods for preparing spherical metal microparticles on the market at present mainly come from atomization methods, including gas atomization methods, water atomization methods and centrifugal atomization methods. The powder prepared by the method contains a large amount of satellite droplets, namely small particle powder is attached to powder particles, and meanwhile, the powder also has the defects of hollow powder and the like, so that the flowability, the powder laying performance and the compactness of the powder are seriously influenced. The powder obtained by atomization must be screened for many times to obtain the powder meeting the requirements, and the yield is low, which seriously affects the quality of the finished piece. Therefore, the conventional atomization method is difficult to satisfy the requirements of 3D packaging technology and additive manufacturing technology economically and technically. In addition, the uniformity of the droplets is difficult to ensure in the process of preparing the droplets by the traditional method, the change of experimental parameters is difficult to control, and the production continuity is poor.
In view of the above, it is desirable to provide a method and an apparatus for preparing uniform, stable and controllable micro-droplet spherical metal particles, so as to solve the problems in the prior art.
Disclosure of Invention
According to the technical problems of low sphericity and uneven particle size distribution of the micron-sized particles, a method for efficiently preparing the micron-sized spherical metal particles with uniform and controllable particle sizes and a preparation device thereof are provided. Under the protection of Ar gas or He gas, metal melt in a molten state is filled in a crucible and a molten pool, the pressure difference between the inside and the outside of the crucible is stabilized between 0-100kPa, and a transmission rod below piezoelectric ceramics acts on the metal melt below the crucible under the driving of a pulse signal, so that micro liquid drops are ejected from a single or a plurality of micropores at the bottom of the crucible. The metal droplets solidify without a container in the falling process to form metal microparticles. The invention uses the diameter information of the falling metal liquid drop collected by the image collecting system and feeds the diameter information back to the differential pressure controller through the control of the computer program to automatically adjust the parameters such as differential pressure, pulse waveform and the like, so that the particle diameter of the prepared particles is always in a set value, meanwhile, the liquid level control system is additionally arranged to adjust the liquid level in the crucible to be always constant, and the continuous production can also be realized by additionally arranging the feeding device to supply raw materials.
The technical means adopted by the invention are as follows:
a method for efficiently preparing micron-sized spherical metal microparticles with uniform and controllable particle sizes is characterized by comprising the following steps:
at vacuum degree lower than 10-3Under the condition of Pa, melting the metal in the crucible into a liquid state; protective gas is introduced into the crucible and the vacuum chamber, a positive pressure difference which is constant at 0-100kPa is formed between the crucible and the vacuum chamber under the control of a differential pressure controller, meanwhile, a certain pulse signal is applied to the piezoelectric ceramic to drive a transmission rod below the piezoelectric ceramic to generate micro displacement, the piezoelectric ceramic acts on a melt near a micropore at the bottom of the crucible, a certain volume of micro liquid is ejected from the micropore at the bottom of the crucible, after a metal liquid drop is formed, the metal liquid drop performs radiation heat exchange and convection heat exchange with the surrounding environment in the falling process, and the metal liquid drop is rapidly solidified to form spherical metal microparticles.
And further, a pre-collection step is set, the pre-collected metal droplet image is collected through an image collection device, the collected metal droplet diameter data is processed and then fed back to a differential pressure controller to adjust differential pressure, and the diameter of the metal droplet is always in a set value.
Further, a raw material supply and liquid level control step is arranged, liquid level height in the crucible and the molten pool is controlled and adjusted according to the preset particle size of the prepared metal particles through a liquid level control program, liquid metal in the molten pool is supplied to the crucible, the liquid level height is kept unchanged, and continuous production is realized.
Further, the metal is melted into a liquid state, then the heat preservation operation is carried out, and the heating temperature is monitored in real time.
The method comprises the following specific steps:
s1, raw material loading: fixing a microporous sheet with micropores at the bottom of a crucible, adding a metal raw material into the crucible and a molten pool, and fixing the metal raw material in a vacuum chamber.
S2, vacuumizing: opening balance valve on the communicating pipe, communicating the crucible with the vacuum chamber, and vacuumizing the crucible and the vacuum chamber to less than 10 ℃ by using a mechanical pump and a molecular pump-3Pa, filling inert protective gas Ar or He, repeating for several times, and finally making the pressure in the vacuum chamber reach one atmosphere.
S3, heating to melt the raw materials: heating by using a heating coil to melt the metal in the crucible and the molten pool, monitoring the heating temperature in real time by using an infrared thermometer, and preserving the heat for 10-25 minutes after the metal is melted.
S4, preparing spherical metal microparticles by a pulse micropore injection method: closing a balance valve on a communicating pipe, opening a pre-collecting disc, adjusting a differential pressure controller to enable the differential pressure between the crucible and the vacuum chamber to be stabilized at 0-100kPa (preferably 1-50kPa), editing a pulse signal by using a signal generator and applying the pulse signal to piezoelectric ceramics, wherein the piezoelectric ceramics generate micro displacement under the driving action of the pulse signal, and the micro displacement is acted on the metal melt at the bottom of the crucible by a transmission rod, so that the liquid is ejected from micropores to form metal liquid drops.
S5, obtaining liquid drops with uniform and controllable particle size: the computer calculates the diameter of the liquid drop according to the metal micro-liquid drop image shot by the high-speed camera by using image analysis software, and feeds back the diameter of the liquid drop to the differential pressure controller and the signal generator for parameter adjustment so that the diameter of the liquid drop is always in a set value.
S6, container-free rapid solidification: and closing the pre-collecting disc, and performing radiation heat exchange and convection heat exchange on the uniform spherical metal liquid drops formed by spraying and the surrounding environment in the falling process, and finally solidifying without a container to form spherical metal micro-particles with uniform and controllable particle sizes.
S7, raw material supply and liquid level control: the liquid level regulator of the liquid level control system can control the liquid level height in the crucible and the molten pool according to the particle size of the prepared particles; the feeding device automatically controls the supply of raw materials according to the change condition of the metal melt in the crucible and the molten pool fed back by the computer, thereby realizing continuous production. In the existing device, the liquid level is constantly changed, and the liquid level height has influence on the preparation of particles, so that the device can keep the liquid level unchanged and continuously produce. The required liquid level height is different when preparing particles of different particle size. The liquid level regulator regulates the height of the liquid level according to the particle size of the prepared particles.
The invention also discloses a preparation device for efficiently preparing the micron-sized spherical metal microparticles with uniform and controllable particle sizes, which is characterized by comprising the following steps:
the vacuum system is used for vacuumizing a vacuum cavity in the device;
the liquid drop spraying system is arranged at the top of the vacuum chamber and used for spraying liquid drops, and the piezoelectric ceramic inside the liquid drop spraying system applies pressure to the transmission rod and controls the dropping frequency of the liquid drops in cooperation with the differential pressure controller; the vibration frequency of the piezoelectric ceramic is between 1Hz and 2kHz, and the crucible and the microporous sheet are made of high-purity graphite, BN and ZrO2Or Al2O3(ii) a The transmission rod is made of Al2O3、BN、ZrO2；
The image acquisition system is arranged on the inner wall of the vacuum chamber and is used for acquiring a pre-collected metal droplet image and feeding the pre-collected metal droplet image back to the differential pressure controller to adjust the differential pressure;
the particle collector is arranged at the bottom of the vacuum chamber, is positioned on the same axis with the liquid drop spraying system, and is used for collecting the metal particles;
and the liquid level control system is arranged on one side of the liquid drop injection system and is used for adjusting the liquid level height in the crucible and the molten pool of the feeding device according to the set pressure difference parameter, wherein the feeding device is used for supplying liquid metal in the crucible.
Further, the device also comprises a pre-collecting disc movably arranged between the liquid drop spraying system and the particle collector and used for pre-collecting the metal liquid drops.
Further, vacuum system includes vacuum chamber, mechanical pump and molecular pump, the molecular pump is installed on the vacuum chamber lateral wall, the mechanical pump is connected with the molecular pump, still is equipped with cavity intake pipe and communicating pipe in the vacuum chamber, install the balanced valve on the one side that communicating pipe links to each other with the vacuum chamber, the communicating pipe opposite side links to each other with the crucible, still be equipped with the crucible intake pipe that links to each other with the crucible in the vacuum chamber, the other end of crucible intake pipe links to each other with differential pressure controller.
Furthermore, the liquid drop spraying system adopts a crucible fixed in a vacuum chamber as a bearing container, a micro-porous sheet provided with one or more circular micro-pores is fixed at the bottom of the crucible, the lower end of a transmission rod is positioned at the upper end of the micro-porous sheet, the transmission rod sequentially penetrates through the top of the crucible and the top of the vacuum chamber to be connected with piezoelectric ceramics, a heating coil is arranged on the periphery of the crucible, and an infrared thermometer is arranged on the inner wall of the vacuum chamber.
Further, when the number of the micropores is one, the hole center of the micropore is positioned at the center of the micropore sheet; when the micropore is a plurality of micropores, the hole center of each micropore is positioned on the circumference taking the micropore sheet as the center of the circle, the included angle of the connecting line between the hole center and the center of the micropore sheet is equal, and the diameter range of the micropore is 0.020-1.000 mm.
Furthermore, the feeding device comprises a molten pool, a liquid level regulator arranged in the molten pool and a U-shaped connecting pipe connected with the crucible, wherein the liquid level regulator is used for regulating the liquid level height of the molten pool and the liquid level height of the crucible so as to control the liquid pressure near the micropores. The molten pool is made of materials which do not react with metal at high temperature and contains metal melt; the U-shaped connecting pipe is connected with the molten pool and the crucible to form a communicating vessel, so that the liquid levels of the crucible and the molten pool are always at the same height. The feeding device is connected with the computer, and gives an instruction to the feeding device according to the reduction information of the quality of the metal melt in the crucible and the molten pool fed back by the computer, so as to automatically convey and supply raw materials.
Compared with the prior art, the invention has the following advantages:
1. the key points of the POEM (pulse micropore injection method) for preparing the micron-sized spherical metal microparticles with uniform and controllable particle sizes are that the pressure difference between the inside and the outside of the crucible is kept stable and the piezoelectric ceramics generate the consistency of micro displacement, so that the POEM is easier to realize compared with other forming methods and is not influenced by external disturbance, and therefore the thermal histories of the particles are consistent, and the sizes, the sphericity and the microstructure of the microparticles are necessarily consistent.
2. Compared with low-temperature equipment, the high-temperature equipment is more complex, the heating mode is changed from simple resistance heating to induction heating, and the materials for manufacturing the crucible and the microporous sheet are high-purity graphite, BN and Al with good mechanical property and high melting point2O3、ZrO2The material of the transmission rod is selected from high-purity graphite and Al with high-temperature strength2O3BN, meeting the requirement of preparing high-melting-point particles.
3. The aperture of the micropores in the device is in the range of 0.020-1.000mm, the vibration frequency of the piezoelectric ceramic is in the range of 1Hz-2kHz, and spherical metal particles can be prepared according to the required size and preparation frequency. The range of the grain diameter of the prepared material is expanded, the preparation frequency is controllable in a wider range, in addition, the stable differential pressure between the crucible and the vacuum chamber is 0-100kPa, the range of the differential pressure is increased, and the range of the grain diameter of the prepared particles is also expanded.
4. The invention adopts an automatic means, realizes the regulation and control of differential pressure and liquid level by executing a computer program, analyzes the particle size data in the image transmitted by a high-speed camera by utilizing the computer program, and regulates the dynamic parameters of a pulse generator and a differential pressure controller, so that the particle size of the prepared particles is always in a set value; the liquid level control system is used for controlling and adjusting the liquid level in the crucible and the molten pool according to the particle size of the prepared particles, the feeding device automatically supplies raw materials, the liquid level is kept unchanged, and continuous production is realized.
In conclusion, the particles prepared by the method and the device have uniform and controllable particle size, high sphericity and strong process controllability, the preparation accuracy is improved, the requirement of continuous industrial production can be met, and the production efficiency is doubled compared with that of the prior preparation method.
Based on the reasons, the invention can be widely popularized in the field of spherical metal particle preparation.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic diagram of an apparatus for efficiently preparing micron-sized spherical metal particles with uniform and controllable particle size.
Fig. 2 is a schematic structural view of the microporous sheet of fig. 1.
FIG. 3 is a scanning electron microscope image of copper particles of uniform and controllable particle size prepared by the pulsed microjet method in example 1.
FIG. 4 is a scanning electron microscope image of uniform and controllable diameter aluminum particles prepared by the pulsed microjet method in example 2.
In the figure: 1. piezoelectric ceramics; 2. a transmission rod; 3. a communicating pipe; 4. a balancing valve; 5. a molten pool; 6. a liquid level regulator; 7. a feeding device; 8. an infrared thermometer; 9. a U-shaped connecting pipe; 10. a microporous sheet; 11. micropores; 12. a molecular pump; 13. a mechanical pump; 14. a chamber air inlet pipe; 15. a particle collector; 16. a droplet; 17. metal microparticles; 18. a vacuum chamber; 19. a pre-collection tray; 20. a support; 21. a high-speed camera; 22. a crucible; 23. a heating coil; 24. a differential pressure controller; 25. a computer; 26. a crucible air inlet pipe; 27. a signal generator; 28. and (4) melting the melt.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. Any specific values in all examples shown and discussed herein are to be construed as exemplary only and not as limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
In the description of the present invention, it is to be understood that the orientation or positional relationship indicated by the directional terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc., are generally based on the orientation or positional relationship shown in the drawings, and are used for convenience of description and simplicity of description only, and in the absence of any contrary indication, these directional terms are not intended to indicate and imply that the device or element so referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore should not be considered as limiting the scope of the present invention: the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.
Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of the present invention should not be construed as being limited.
Example 1
As shown in FIGS. 1 and 2, the device for efficiently preparing spherical metal particles with uniformly controllable particle diameters, according to the present invention, comprises a vacuum system, a droplet spraying system, an image capturing system and a particle collector.
The vacuum system comprises a vacuum chamber 18, a particle collector 15 is arranged at the bottom of the vacuum chamber 18, a liquid drop spraying system is arranged at the top of the vacuum chamber 18 and is positioned right above the particle collector 15, an image acquisition system is connected onto the vacuum chamber 18 of the vacuum system, a pre-collecting disc 19 is movably arranged between the liquid drop spraying system and the particle collector 15 through a support 20, and the pre-collecting disc 19 is arranged for removing particles which have inconsistent sizes or have oxide layers formed on the surfaces in the initial stage and improving the yield of products; on the other hand, the particles with different particle sizes prepared under different parameters can not be mixed together, specifically, the pre-collecting tray 19 is opened at the initial stage of collecting the particles, the prepared particles fall into the pre-collecting tray 19, and the prepared particles are not subjected to various feedback adjustments, so that the particle sizes are not uniform. When the parameters are feedback-adjusted to the optimum parameters, the pre-collector tray 19 is closed and the particles of uniform size fall into the collection tank below.
The vacuum system comprises a vacuum chamber 18, a mechanical pump 13 and a molecular pump 12, wherein the molecular pump 12 is arranged on the side wall of the vacuum chamber 18, the mechanical pump 13 is connected onto the molecular pump 12, a chamber air inlet pipe 14 and communicating pipes 3 are further arranged on the vacuum chamber 18, a balance valve 4 is arranged between the communicating pipes 3, a crucible air inlet pipe 26 controlled by a differential pressure controller 24 is arranged on a crucible 22, the balance valve 4 is opened during vacuumizing, and the crucible 22 and the vacuum chamber 18 can be vacuumized simultaneously. The balance valve 4 is closed, and the differential pressure between the crucible 22 and the vacuum chamber 18 can be controlled by the differential pressure controller 24.
The liquid drop spraying system adopts a crucible 22 to be fixedly arranged inside a vacuum chamber 18, a micro-porous sheet 10 provided with circular micro-pores 11 is fixedly arranged at the bottom of the crucible 22, the lower end of a transmission rod 2 is positioned on the upper surface of the micro-porous sheet 10, the upper end of the transmission rod 2 sequentially penetrates through the top of the crucible 22 and the top of the vacuum chamber 18 to be connected with piezoelectric ceramics 1, the piezoelectric ceramics 1 is connected with a signal generator 27, and the signal generator 27 is connected with a computer 25; the heating coil 23 is installed on the periphery of the crucible 22, the infrared thermometer 8 is located inside the vacuum chamber 18, and the other end is connected with the computer 25.
The micro-pores 11 are single pores only in the center of the micro-porous sheet 10, and have a pore diameter of 0.350 mm.
The vibration frequency of the piezoelectric ceramic 1 is 100Hz, the crucible 22 and the microporous sheet 10 are made of high-purity graphite, and the transmission rod 2 is made of Al2O3Meanwhile, the selection of the materials of the crucible 22 and the transmission rod 2 improves the stability and the precision of the preparation process.
The particle collector 15 is fixedly installed at the bottom of the vacuum chamber 18, and is hermetically connected to the vacuum chamber 18.
The image acquisition system is mounted on the side wall of the vacuum chamber 18 using a high speed camera 21 and is connected to a computer 25.
The method for preparing the metal copper powder by adopting the equipment comprises the following specific steps:
(1) charging: fixing a microporous sheet 10 with a micropore 11 at the center at the bottom of a crucible 22, and adding oxygen-free copper (brand TU2) to be prepared into the crucible 22 and a molten pool 5;
(2) vacuumizing: the balance valve 4 is opened, the crucible 22 is communicated with the vacuum chamber 18, and the crucible 22 and the vacuum chamber 18 are vacuumized to 10 degrees by the mechanical pump 13 and the molecular pump 12-3Below Pa, filling inert protective gas Ar or He, repeating for several times, and finally making the pressure in the vacuum chamber 18 reach one atmosphere;
(3) melting metal: heating and melting the metal copper in the crucible 22 by using a heating coil 23, monitoring the temperature of the crucible 22 in real time by using an infrared thermometer 8, and preserving the heat for 10 minutes after the metal copper is completely melted;
(4) preparing copper particles by a pulse micropore spraying method: closing the balance valve 4, isolating the crucible 22 from the vacuum chamber 18, opening the pre-collecting disc 19, controlling a crucible air inlet pipe 26 through a differential pressure controller 24 to introduce inert gas into the crucible 22, enabling the differential pressure between the crucible 22 and the vacuum chamber 18 to reach 3kPa, editing a pulse signal by using a signal generator 27 and applying the pulse signal to the piezoelectric ceramic 1, wherein the piezoelectric ceramic 1 generates micro displacement under the driving of the pulse signal and drives the transmission rod 2 to move, and the micro displacement is acted on the metal copper melt 28 at the bottom of the crucible 22 by the transmission rod 2, so that micro metal copper droplets 16 are ejected from the micropores 11 to form metal copper microparticle droplets;
(5) uniform droplets were obtained: the computer 25 calculates the diameter of the metal copper particle droplet 16 from the image of the droplet 16 captured by the high-speed camera 21 by using image analysis software, compares the diameter with diameter data stored in a database established by a large number of experiments in the computer 25, feeds back the diameter data to the differential pressure controller 24 and the signal generator 27, and adjusts parameters (controls differential pressure by the differential pressure controller, controls waveform t of the pulse generator by the differential pressure controller)up，tup100-;
(6) container-free rapid solidification: the pre-collecting disc 19 is closed, the sprayed uniform metal droplets 16 are subjected to radiation heat exchange and convection heat exchange with the surrounding environment in the falling process, and the containerless uniform metal droplets are solidified to form spherical metal copper particles and finally fall into the particle collector 15.
(7) The raw material is supplemented and the liquid level is controlled, the feeding device 7 supplements the raw material according to the quantity information of the prepared particles fed back by the computer 25, the liquid level is kept unchanged, and the continuous production is realized. The level controller 6 of the level control system controls the levels of the molten pool 5 and the crucible 22 according to the set values. In the existing device, the liquid level is constantly changed, and the liquid level height has influence on the preparation of particles, so that the device can keep the liquid level unchanged and continuously produce. The required liquid level height is different when preparing particles of different particle size. The liquid level adjuster 6 adjusts the liquid level height according to the particle size of the prepared particles.
The picture of the prepared metal copper microparticles observed by a scanning electron microscope is shown in figure 3, and the micro morphology shows that the prepared particles have uniform particle size, high sphericity and average particle size of 350 microns.
Example 2
Example 2 the same apparatus and preparation as in example 1, the apparatus and method of this example have the following different relevant parameters:
(1) the pore diameter of the micropores 11 is 0.250 mm.
(2) The vibration frequency of the piezoelectric ceramic 1 is 150Hz, and the vibration waveform tup230 μ s; the crucible 22 and the microporous sheet 10 are made of Al2O3(ii) a The transmission rod 2 is made of BN.
(3) Step (1) charging: the metal to be prepared is added as aluminum.
(4) Step (2), vacuumizing: the crucible 22 and the vacuum chamber 18 are evacuated to 10 by the mechanical pump 13 and the molecular pump 12-4Pa or less.
(5) Step (3) melting metal: and preserving the heat for 20 minutes after the metal aluminum is completely melted.
(6) Step (4), preparing metal aluminum particles by a pulse micropore injection method: an inert gas is introduced into the crucible 22 through a crucible inlet pipe 26 controlled by a differential pressure controller 24 so that the differential pressure between the crucible 22 and the vacuum chamber 18 becomes 4 kPa.
The picture of the prepared metal aluminum micro-particle observed by a scanning electron microscope is shown in figure 4, and the micro-morphology shows that the prepared particle has uniform particle size, high sphericity and average particle size of 250 μm.
Example 3
The apparatus and the method of the present example, which are the same as those of the apparatus and the method of the present example 1, have the following parameters:
(1) the micropores 11 of the device are 6 holes distributed on an arc with the center of the microporous sheet 10 as the center, the angle between every two holes is 60 degrees, the diameter of the micropore is 0.350mm, and the speed of preparing particles is 6 times of that of the embodiment 1.
(2) The vibration frequency of the piezoelectric ceramic 1 is 200Hz, and the vibration waveform tup300 mus, the crucible 22 and the microporous sheet 10 are made of high purity graphite, and the transmission rod 2 is made of Al2O3。
(3) Step (1) charging: the metal to be prepared is added to the copper metal.
(4) Step (2), vacuumizing: the crucible and vacuum chamber 18 were evacuated to 10-3Pa by mechanical pump 13 and molecular pump 12.
(5) Step (3) melting metal: and keeping the temperature for 15 minutes after the copper is completely melted.
(6) Step (4), preparing copper particles by a pulse micropore injection method: an inert gas is introduced into the crucible 22 through a crucible inlet pipe 26 controlled by a differential pressure controller 24 so that the differential pressure between the crucible 22 and the vacuum chamber 18 becomes 2 kPa.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A method for efficiently preparing micron-sized spherical metal microparticles with uniform and controllable particle sizes is characterized by comprising the following steps: in thatVacuum degree lower than 10-3Under the condition of Pa, melting the metal in the crucible into a liquid state; protective gas is introduced into the crucible and the vacuum chamber, a positive pressure difference which is constant at 0-100kPa is formed between the crucible and the vacuum chamber under the control of a differential pressure controller, meanwhile, a certain pulse signal is applied to the piezoelectric ceramic to drive a transmission rod below the piezoelectric ceramic to generate micro displacement, the piezoelectric ceramic acts on a melt near a micropore at the bottom of the crucible, a certain volume of micro liquid is ejected from the micropore at the bottom of the crucible, after a metal liquid drop is formed, the metal liquid drop performs radiation heat exchange and convection heat exchange with the surrounding environment in the falling process, and the metal liquid drop is rapidly solidified to form spherical metal microparticles.
2. The method according to claim 1, wherein the pre-collecting step is performed by collecting the pre-collected metal droplet image with an image collecting device, processing the collected metal droplet diameter data and feeding the processed data back to a differential pressure controller to adjust the differential pressure, so that the diameter of the metal droplet is always at a predetermined value.
3. The method for efficiently preparing micron-sized spherical fine metal particles with uniform and controllable particle sizes according to claim 2, wherein a raw material supply and liquid level control step is provided, the liquid level in the crucible and the molten bath is controlled and adjusted according to the preset particle sizes of the prepared fine metal particles through a liquid level control program, liquid metal in the molten bath is supplied to the crucible, and the liquid level is kept constant, so that continuous production is realized.
4. The method of claim 1, wherein the metal is melted into a liquid state, and then the heat-insulating operation is performed, and the heating temperature is monitored in real time.
5. A preparation device for efficiently preparing micron-sized spherical metal microparticles with uniform and controllable particle sizes is characterized by comprising the following components:
the vacuum system is used for vacuumizing a vacuum cavity in the device;
the liquid drop spraying system is arranged at the top of the vacuum chamber and used for spraying liquid drops, and the piezoelectric ceramic inside the liquid drop spraying system applies pressure to the transmission rod and controls the dropping frequency of the liquid drops in cooperation with the differential pressure controller;
the image acquisition system is arranged on the inner wall of the vacuum chamber and is used for acquiring a pre-collected metal droplet image and feeding the pre-collected metal droplet image back to the differential pressure controller to adjust the differential pressure;
the particle collector is arranged at the bottom of the vacuum chamber, is positioned on the same axis with the liquid drop spraying system, and is used for collecting the metal particles;
and the liquid level control system is arranged on one side of the liquid drop injection system and is used for adjusting the liquid level height in the crucible and the molten pool of the feeding device according to the set pressure difference parameter, wherein the feeding device is used for supplying liquid metal in the crucible.
6. The apparatus of claim 5, further comprising a pre-collecting tray movably installed between the droplet spraying system and the particle collector for pre-collecting the metal droplets.
7. The apparatus according to claim 5, wherein the vacuum system comprises a vacuum chamber, a mechanical pump and a molecular pump, the molecular pump is mounted on a sidewall of the vacuum chamber, the mechanical pump is connected to the molecular pump, a chamber air inlet pipe and a communicating pipe are further disposed in the vacuum chamber, a balance valve is mounted on one side of the communicating pipe connected to the vacuum chamber, the other side of the communicating pipe is connected to the crucible, a crucible air inlet pipe connected to the crucible is further disposed in the vacuum chamber, and the other end of the crucible air inlet pipe is connected to a differential pressure controller.
8. The apparatus of claim 5, wherein the droplet spraying system comprises a crucible fixed inside a vacuum chamber as a container, a micro-porous plate having one or more circular micro-pores is fixed at the bottom of the crucible, a lower end of a driving rod is located at an upper end of the micro-porous plate, the driving rod is connected to the piezoelectric ceramic sequentially passing through the top of the crucible and the top of the vacuum chamber, a heating coil is disposed around the crucible, and an infrared thermometer is installed on an inner wall of the vacuum chamber.
9. The apparatus for efficiently preparing micron-sized spherical metal microparticles with uniformly controllable particle diameters according to claim 8, wherein when there is one micropore, the center of the pore is located at the center of the microporous sheet; when the micropore is a plurality of micropores, the hole center of each micropore is positioned on the circumference taking the micropore sheet as the center of the circle, the included angle of the connecting line between the hole center and the center of the micropore sheet is equal, and the diameter range of the micropore is 0.020-1.000 mm.
10. The apparatus according to claim 5, wherein the feeding device comprises a molten pool, a liquid level regulator disposed in the molten pool, and a U-shaped connecting tube connected to the crucible, the liquid level regulator is used for regulating the liquid level in the molten pool and the crucible, and further controlling the liquid pressure near the micropores.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116160007A (en) * | 2023-04-24 | 2023-05-26 | 成都佩克斯新材料有限公司 | Gold-tin powder preparation device and preparation method |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020056950A1 (en) * | 2000-03-14 | 2002-05-16 | Koji Sato | Apparatus for producing fine metal balls |
| CN101138791A (en) * | 2007-10-16 | 2008-03-12 | 天津大学 | Even-sized particles producing device and method for preparing the same |
| CN101934374A (en) * | 2010-07-29 | 2011-01-05 | 大连理工大学 | Method and device for preparing low melting point solder balls |
| CN103008672A (en) * | 2012-12-14 | 2013-04-03 | 大连理工大学 | Method and device for efficiently preparing uniform spherical micro-particle through pulse small-hole multi-vibrating-rod injection process |
| CN107824793A (en) * | 2017-10-31 | 2018-03-23 | 中国科学院过程工程研究所 | A kind of device and method for preparing ultra-fine single dispersion metal microballoon |
-
2021
- 2021-04-29 CN CN202110476958.8A patent/CN113263181A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020056950A1 (en) * | 2000-03-14 | 2002-05-16 | Koji Sato | Apparatus for producing fine metal balls |
| CN101138791A (en) * | 2007-10-16 | 2008-03-12 | 天津大学 | Even-sized particles producing device and method for preparing the same |
| CN101934374A (en) * | 2010-07-29 | 2011-01-05 | 大连理工大学 | Method and device for preparing low melting point solder balls |
| CN103008672A (en) * | 2012-12-14 | 2013-04-03 | 大连理工大学 | Method and device for efficiently preparing uniform spherical micro-particle through pulse small-hole multi-vibrating-rod injection process |
| CN107824793A (en) * | 2017-10-31 | 2018-03-23 | 中国科学院过程工程研究所 | A kind of device and method for preparing ultra-fine single dispersion metal microballoon |
Non-Patent Citations (1)
| Title |
|---|
| 鲁栋: "脉冲微孔均匀金属液滴喷射沉积成型技术研究", 《中国优秀博硕士学位论文全文数据库(硕士)医药卫生科技辑》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116160007A (en) * | 2023-04-24 | 2023-05-26 | 成都佩克斯新材料有限公司 | Gold-tin powder preparation device and preparation method |
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