CN112935264A - Device and method for jetting and solidifying monodisperse micro-droplets based on giant magnetostriction drive - Google Patents

Device and method for jetting and solidifying monodisperse micro-droplets based on giant magnetostriction drive Download PDF

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CN112935264A
CN112935264A CN202110105860.1A CN202110105860A CN112935264A CN 112935264 A CN112935264 A CN 112935264A CN 202110105860 A CN202110105860 A CN 202110105860A CN 112935264 A CN112935264 A CN 112935264A
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crucible
micro
giant magnetostrictive
giant
rod
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CN112935264B (en
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许富民
董伟
李安平
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Dalian University of Technology
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Dalian University of Technology
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • 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
    • B22F9/082—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 atomising using a fluid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • 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
    • B22F9/082—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 atomising using a fluid
    • B22F2009/0892—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 atomising using a fluid casting nozzle; controlling metal stream in or after the casting nozzle

Abstract

The invention provides a device and a method for driving monodisperse micro-droplet injection and solidification based on giant magnetostriction. The method is based on the giant magnetostrictive principle, utilizes the unique performance of the giant magnetostrictive material, uses the giant magnetostrictive micro-displacement driver to drive the injection of micro liquid drops, and improves the stability, the precision and the injection efficiency of single liquid drops injected from micropores, thereby generating high-quality micron or even ultra-micron particles meeting the industrial requirements.

Description

Device and method for jetting and solidifying monodisperse micro-droplets based on giant magnetostriction drive
Technical Field
The invention relates to a device and a method for driving monodisperse micro-droplet injection and solidification based on giant magnetostriction.
Background
With the technological revolution, the demand of industry for spherical metal particles is increasing. The traditional particle preparation technology such as an atomization method, a tube dropping method and the like has the defects that the flying tracks of sprayed liquid drops are inconsistent, the thermal histories are different, the prepared particles are not high in sphericity and uneven in size, and can be used only by screening, so that the production efficiency is greatly reduced. Particularly, when the size is strictly required, the atomization method is easy to generate satellite droplets, so that the satellite droplets are adhered to the surface of the particles, the fluidity and the spreadability of the particles are reduced, and the requirement of the industry on high-quality particles cannot be met.
In the system for preparing monodisperse particles by droplet injection, a driver can drive a transmission rod to generate a longitudinal micro displacement to act on a melt at the bottom of a crucible, so that droplets are ejected from micropores at the bottom of the crucible. Therefore, the effect of the lifting driver is very important to improve the liquid drop spraying effect.
At present, a micro-droplet jetting system based on piezoelectric ceramics (PZT) as a driver can jet monodisperse droplets, but a piezoelectric ceramic micro-displacement actuator has small output power, small output displacement range and higher working voltage, and due to the laminated structure of the PZT, irregular strain and creep deformation are generated under the working load to cause a drift phenomenon, and the size is also increased. In addition, the operating temperature of the piezoelectric ceramic should be set to be less than half of the curie temperature thereof, and the polarization of the piezoelectric ceramic is permanently lost due to instantaneous overheating, so that the piezoelectric ceramic is not resistant to high temperature, and strict heat-shielding setting for PZT is necessary, so that the ejection effect of the droplets of the piezoelectric ceramic as the driving unit is affected, and the droplet ejection system is difficult to be miniaturized.
Disclosure of Invention
According to the existing micro-droplet ejection system based on piezoelectric ceramics (PZT) as a driver, monodisperse droplets can be ejected, but the piezoelectric ceramic micro-displacement actuator has small output power, small output displacement range and higher working voltage, and due to the laminated structure of the PZT, irregular strain and creep are generated under the working load to cause a drift phenomenon, and the size is also increased; in addition, the working temperature of the piezoelectric ceramic should be set to be less than half of the curie temperature, the polarization of the piezoelectric ceramic is permanently lost due to instant overheating, so the piezoelectric ceramic is not resistant to high temperature, and the PZT needs to be strictly heat-proof, so the ejection effect of the piezoelectric ceramic as the driving unit liquid drop is influenced, and the liquid drop ejection system is difficult to be miniaturized, and a device and a method for driving the ejection and solidification of the monodisperse micro liquid drop based on the giant magnetostriction are provided. Based on the giant magnetostrictive principle, the giant magnetostrictive micro-displacement driver is used for driving the injection of micro liquid drops by utilizing the unique performance of the giant magnetostrictive material, so that the stability, the precision and the injection efficiency of single liquid drops injected from micropores can be improved, and high-quality micron and even ultra-micron particles meeting the industrial requirements are generated.
The technical means adopted by the invention are as follows:
a device based on super magnetostriction drives the little liquid droplet of monodispersion to spray and solidify, including: the device comprises an upper shell, a lower shell, a giant magnetostrictive micro-displacement driver arranged above the outer part of the upper shell, a crucible arranged in the upper shell and a micro-particle collecting region arranged at the bottom of the lower shell, wherein the crucible is arranged at the upper part of the micro-particle collecting region, and the giant magnetostrictive micro-displacement driver is positioned at the upper part of the crucible;
a crucible cavity is arranged in the crucible and used for containing a melt; a transmission rod connected with the giant magnetostrictive actuator is arranged in the crucible, the position where the transmission rod is connected with the top of the crucible is sealed by a dynamic sealing ring, the lower end of the transmission rod is opposite to a central hole at the bottom of the crucible, and a microporous gasket with a small hole is fixed at the bottom of the central hole through a screw; a heater is arranged outside the crucible;
the top of the upper shell is provided with a crucible air inlet pipe and a crucible exhaust pipe which extend into the crucible, the side wall of the upper shell is connected with the crucible and is provided with a diffusion pump and a mechanical pump, and the upper shell is also provided with a cavity air inlet valve and a cavity exhaust valve;
the micro-particle collecting region comprises an annular dropping pipe and a collecting disc, wherein two sides of the annular dropping pipe are respectively communicated with the upper shell and the lower shell and are used for dropping liquid drops sprayed from small holes on the microporous gasket, the lower end of the annular dropping pipe is opposite to the collecting disc, and the collecting disc can collect particles by rotating and replacing discs with different sizes;
the giant magnetostrictive micro-displacement driver is used for driving the injection of micro liquid drops, a giant magnetostrictive rod is arranged in the middle of the driver, the upper end of the transmission rod is connected with the giant magnetostrictive rod, a permanent magnet, a magnetic yoke, an excitation coil and a side magnetic wall are sequentially arranged outside the giant magnetostrictive rod, end magnetic conduction blocks are arranged on the upper part and the lower part of the driver, a pre-pressing block is arranged at the top of the end magnetic conduction block on the upper part, and the upper end of the transmission rod is connected with the end magnetic conduction block on the lower part; the upper part and the lower part of the excitation coil are respectively provided with an upper magnetizer and a lower magnetizer; the permanent magnet, the end part magnetic conduction block, the upper magnetizer, the lower magnetizer, the side magnetic conduction wall and the giant magnetostrictive rod form a closed magnetic circuit; the lower end cover of the giant magnetostrictive micro-displacement driver is provided with a spring set, so that the pre-pressure can be conveniently adjusted; a gasket is arranged between the top of the spring group and the bottom end of the top of the transmission rod, and a pressure sensor is arranged between the bottom of the spring group and the lower end cover.
Further, the microporous gasket is made of a high temperature and corrosion resistant material.
Furthermore, the diameter of the central hole of the crucible is larger than that of the small hole of the microporous gasket, and the diameter range of the small hole of the microporous gasket is between 0.5 and 500 microns;
the material of the microporous gasket has a wetting angle with a melt disposed within the crucible of greater than 90 °.
Furthermore, the framework of the excitation coil is designed into an annular hollow form, an annular closed cavity in the framework is used as a cooling chamber, and both the giant magnetostrictive rod and the excitation coil exchange heat with the framework;
cooling water enters the cooling chamber from the water inlet, directly exchanges heat with the framework, takes away heat transferred by the giant magnetostrictive rod and the magnet exciting coil, and then is discharged from the water outlet;
the framework is arranged between the giant magnetostrictive rod and the magnet exciting coil, and the heat generated by the magnet exciting coil is isolated from transferring the giant magnetostrictive rod, so that the magnet exciting coil and the giant magnetostrictive rod are rapidly and sufficiently cooled, and the deformation of the giant magnetostrictive rod is effectively controlled.
Further, the giant magnetostrictive rod, the transmission rod, the central hole of the crucible, the small hole of the microporous gasket and the annular descending pipe are positioned on the same axis.
Furthermore, at least one thermocouple is arranged in the upper shell, and a probe used for monitoring the temperature on the thermocouple extends into the melt in the crucible during the experiment to measure the temperature of the melt in the crucible.
The invention also provides a method for driving the jetting and solidification of the monodisperse micro-droplet based on the giant magnetostriction, which comprises the following steps:
s1, charging: putting a metal material to be melted into a crucible cavity of a crucible arranged in an upper shell and then sealing; wherein the loading amount of the metal material loaded into the crucible cavity is about two thirds of the volume of the crucible cavity;
s2, vacuumizing and washing gas: vacuumizing the crucible, the upper shell and the lower shell by using a mechanical pump and a diffusion pump, starting the mechanical pump to pump low vacuum to be below 5Pa, filling high-purity inert protective gas, and then pumping to be below 5Pa, and repeating the operation for 3 times to ensure that the oxygen content in the shell is lower than 10 ppm;
s3, vacuumizing and washing gas: the diffusion pump is turned on to pump high vacuum to 5X 10-3Below Pa, and filling high-purity inert protective gas;
s4, induction heating: setting heating parameters of a heater according to the melting point of the raw material to be heated, monitoring the temperature in the crucible in real time through a thermocouple arranged in the crucible, and preserving the heat for about 20 minutes after the metal material is completely melted;
s5, particle preparation: introducing high-purity inert protective gas through a crucible gas inlet pipe arranged on the upper shell and extending into the crucible, and generating back pressure in the crucible to promote molten metal to fill a central hole at the bottom of the crucible; cooling circulating water is introduced into the giant magnetostrictive actuator, an excitation current signal with a certain frequency is input, the giant magnetostrictive rod generates downward displacement, and the downward displacement is transmitted to molten metal in an area near a central hole by a transmission rod connected with the giant magnetostrictive rod and a microporous gasket arranged below the transmission rod, so that the molten metal is sprayed out from the bottom of the central hole to form uniform liquid drops;
s6, particle collection: the liquid drops drop through the annular descending pipe, and the uniform spherical metal particles are collected by a collecting disc arranged at the bottom of the lower shell.
Compared with the prior art, the invention has the following advantages:
1. the invention provides a device and a method for driving monodisperse micro-droplet ejection and solidification based on giant magnetostriction, and provides a method and a device for applying a giant magnetostriction micro-displacement driver to micro-droplet ejection based on the giant magnetostriction (GMM) principle. And need not strict heat protection and high pressure resistant setting, output dynamics is big in addition, so be convenient for miniaturized design, be favorable to improving the precision of three-dimensional printing equipment based on little liquid drop. Compared with other drivers, the giant magnetostrictive micro-displacement driver has the advantages of simple structure, high response speed, high precision, large output force, low working voltage, almost no fatigue limit and the like. Therefore, the present invention can improve the stability, precision and jetting efficiency of single-beam liquid drops jetted from the micropores, thereby generating high-quality micron and even ultra-micron particles meeting industrial requirements.
2. Compared with nickel, PZT and the like, the device and the method for driving the jetting and solidification of the monodisperse micro-droplet based on the giant magnetostriction have the following performance characteristics by taking the Terfenol-D giant magnetostriction material as an example: (1) large magnetostrictive strain value: 40-50 times larger than nickel and 3-8 times larger than PZT piezoelectric ceramic. At the resonant frequency, the dynamic strain is several times higher than the static strain. A larger magnetostriction coefficient can generate larger displacement output; (2) the energy density is high: can reach 14kJ/m3-25kJ/m3The piezoelectric ceramic is 500 times larger than nickel and 10-14 times larger than PZT piezoelectric ceramic, and the electromechanical coupling coefficient is large, thereby being beneficial to the broadband high-efficiency work of the driver; (3) large input force, low sound velocity: the size of the piezoelectric ceramic is 3 times smaller than that of nickel, which is about 1/2 of PZT piezoelectric ceramic, and the miniaturization design of the driver is facilitated; (4) curie point temperatureThe degree is high, and the reliability is high: transient overheating will cause the polarization of the PZT piezoelectric ceramic to permanently disappear. When the Terfenol-D works to the Curie temperature, the magnetostriction characteristic disappears only temporarily, and when the Terfenol-D is cooled to the Curie temperature, the magnetostriction characteristic can be completely recovered; (5) the response speed is high: the giant magnetostrictive material has extremely high response speed and good repeatability. The response time of Terfenol-D is less than 1 mus.
3. The device and the method for driving the jetting and the solidification of the monodisperse micro liquid drop based on the giant magnetostriction have the advantages that the structure of the giant magnetostriction material based micro displacement driver is simple, and the response time only depends on the excitation time of the driving coil. The GMM rod is driven by applying excitation current to the driving coil to generate an excitation magnetic field. The magnetic energy is converted into mechanical energy by utilizing the physical properties of the material, and the mechanical energy is externally represented as the output of mechanical stress and displacement through the transmission rod. In addition, a bias coil is arranged or a permanent magnet is arranged in the magnetic circuit structure and used for providing a bias magnetic field for GMM work so as to eliminate the frequency doubling phenomenon of materials; the design of the pre-pressing mechanism mainly provides proper pre-pressing stress for the GMM, increases the strain capacity of the GMM and improves the energy conversion efficiency of the GMM; the cooling mechanism is applied primarily to control the temperature rise in the GMM to reduce the effect of temperature changes on GMM control performance. Based on the advantages, the giant magnetostrictive micro-displacement driver is used for micro-droplet jetting, so that the droplet jetting technology is greatly improved.
In conclusion, the technical scheme of the invention can solve the problems that the existing micro-droplet injection system based on piezoelectric ceramics (PZT) as a driver can inject monodisperse droplets, but the piezoelectric ceramic micro-displacement actuator has small output power, small output displacement range and higher working voltage, and due to the laminated structure of the PZT, irregular strain and creep are generated under the working load to cause a drift phenomenon, and the size is also increased; in addition, the working temperature of the piezoelectric ceramic should be set to be less than half of the curie temperature thereof, and the polarization of the piezoelectric ceramic is permanently lost due to instantaneous overheating, so that the piezoelectric ceramic is not resistant to high temperature, and strict heat-shielding setting for PZT is necessary, so that the ejection effect of the droplets of the piezoelectric ceramic as the driving unit is affected, and the droplet ejection system is difficult to be miniaturized.
For the reasons mentioned above, the present invention can be widely applied to the field of particle preparation and the like.
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 view of a giant magnetostrictive driving monodisperse micro-droplet jetting and solidifying device according to the present invention.
FIG. 2 is a schematic diagram of the giant magnetostrictive micro-displacement actuator according to the present invention.
In the figure: 1. pre-tightening a pressing block; 2. an end part magnetic conduction block; 3. an upper magnetizer; 4. a giant magnetostrictive rod; 5. a field coil; 6. a side magnetic wall; 7. a lower magnetizer; 8. a water inlet; 9. a gasket; 10. a spring set; 11. a pressure sensor; 12. a transmission rod; 13. a water outlet; 14. a magnetic yoke; 15. a permanent magnet; 16. melt 17, crucible; 18. a heater; 19. a droplet; 20. an annular drop tube; 21. a collection tray; 22. an upper housing; 23. a microporous gasket; 24. a cavity air inlet valve; 25. a mechanical pump; 26. a diffusion pump; 27. a cavity exhaust valve; 28. a crucible cavity; 29. a crucible exhaust pipe; 30. and (4) feeding gas into the crucible.
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.
Since piezoelectric ceramics (PZT) has various defects in a micro-droplet jetting system using the PZT as an actuator, the prepared micro-particles have a minimum particle size of about 100 μm, and the PZT is difficult to be miniaturized and has a limited lifetime. Therefore, the invention provides a device and a method for jetting and solidifying monodisperse micro liquid drops based on giant magnetostriction drive, wherein the driving force of the giant magnetostriction drive is larger, micron and even ultramicro particles with smaller particle size can be prepared, which is difficult to realize in the past, and the structure can be miniaturized, so that the precision can be improved if the device is used for 3D printing, and for a larger structure, the influence of factors such as inertia and the like is difficult to overcome, in addition, the service life of the giant magnetostriction drive is very long, and the cost can be saved in the realization of industrialization.
Example 1
As shown in fig. 1-2, the present invention provides a device for driving the jetting and solidification of monodisperse microdroplets based on giant magnetostriction, comprising: the device comprises an upper shell 22, a lower shell, a giant magnetostrictive micro-displacement driver arranged above the outer part of the upper shell 22, a crucible 17 arranged in the upper shell 22 and a micro-particle collecting region arranged at the bottom of the lower shell, wherein the crucible 17 is arranged at the upper part of the micro-particle collecting region, and the giant magnetostrictive micro-displacement driver is positioned at the upper part of the crucible 17.
A crucible cavity 28 is arranged in the crucible 17 and is used for containing the melt 16; a transmission rod 12 connected with a giant magnetostrictive driver is arranged in the crucible 17, the position where the transmission rod 12 is connected with the top of the crucible 17 is sealed by a dynamic sealing ring, the lower end of the transmission rod 12 is opposite to a central hole at the bottom of the crucible 17, a microporous gasket 23 with a small hole is fixed at the bottom of the central hole, the microporous gasket 23 can be made of high-temperature-resistant and corrosion-resistant materials, and the microporous gasket 23 with the small hole is fixed at the bottom of the crucible 17 through screws; the crucible 17 is externally provided with a heater 18. Wherein, the diameter of the central hole of the crucible 17 is larger than the diameter of the small hole of the microporous gasket 23, and the diameter range of the small hole of the microporous gasket 23 is between 0.5 and 500 mu m; the wetting angle of the material of microporous gasket 23 with melt 16 placed in crucible 17 is greater than 90 °.
The top of the upper shell 22 is provided with a crucible air inlet pipe 30 and a crucible air outlet pipe 29 which extend into the crucible 17, the side wall of the upper shell is connected with the crucible 17 and is provided with a diffusion pump 26 and a mechanical pump 25, and the upper shell 22 is also provided with a cavity air inlet valve 24 and a cavity air outlet valve 27. In addition, a thermocouple is provided inside the upper housing 22, and a probe for monitoring the temperature of the thermocouple can be extended into the melt 16 inside the crucible 17 during the experiment to measure the temperature of the melt 16 inside the crucible 17.
The particle collecting area comprises an annular drop tube 20 and a collecting tray 21, two sides of the annular drop tube 20 are respectively communicated with an upper shell 22 and a lower shell, and are used for dripping liquid drops 19 sprayed from small holes on a microporous gasket 23 in the annular drop tube, the lower end of the annular drop tube 20 is opposite to the collecting tray 21, and the collecting tray 21 can collect particles by rotating and replacing trays with different sizes.
The giant magnetostrictive micro-displacement driver is used for driving the injection of micro liquid drops, a giant magnetostrictive rod 4(GMM rod) is arranged in the middle of the driver, the upper end of a transmission rod 12 is connected with the giant magnetostrictive rod 4, a permanent magnet 15, a magnetic yoke 14, an excitation coil 5 and a side magnetic wall 6 are sequentially arranged outside the giant magnetostrictive rod 4, end part magnetic conduction blocks 2 are arranged on the upper part and the lower part of the driver, a pre-compaction block 1 is arranged at the top of the end part magnetic conduction block 2 on the upper part, and the upper end of the transmission rod 12 is connected with the end part magnetic conduction block 2 on the lower part; the upper part and the lower part of the excitation coil 5 are respectively provided with an upper magnetizer 3 and a lower magnetizer 7; wherein, the permanent magnet 15, the end part magnetic conduction block 2, the upper magnetizer 3, the lower magnetizer 7, the side magnetic conduction wall 6 and the giant magnetostrictive rod 4 form a closed magnetic circuit; the lower end cover of the giant magnetostrictive micro-displacement driver is provided with a spring group 10, so that the pre-pressure can be conveniently adjusted; a gasket 9 is arranged between the top of the spring group 10 and the bottom end of the top of the transmission rod 12, and a pressure sensor 11 is arranged between the bottom and the lower end cover.
The framework of the excitation coil 5 is designed into an annular hollow form, an annular closed cavity in the framework is used as a cooling chamber, and both the giant magnetostrictive rod 4 and the excitation coil 5 exchange heat with the framework. Cooling water enters the cooling chamber from the water inlet 8, directly exchanges heat with the framework, takes away heat transferred by the giant magnetostrictive rod 4 and the magnet exciting coil 5, and then is discharged from the water outlet 13. The framework is positioned between the giant magnetostrictive rod 4 and the excitation coil 5, and the transmission of heat generated by the excitation coil 5 to the giant magnetostrictive rod 4 is isolated, so that the excitation coil 5 and the giant magnetostrictive rod 4 are rapidly and fully cooled, and the deformation of the giant magnetostrictive rod 4 is effectively controlled.
The giant magnetostrictive rod 4, the transmission rod 12, the central hole of the crucible 17, the small hole of the microporous gasket 23 and the annular descent tube 20 are positioned on the same axis.
Example 2
On the basis of embodiment 1, the invention also provides a method for driving the jetting and solidification of monodisperse micro liquid drops based on giant magnetostriction, which comprises the following steps:
s1, charging: the metal material to be melted is put into a crucible cavity 28 of the crucible 17 arranged in the upper shell 22 and then sealed; wherein the loading amount of the metal material into the crucible cavity 28 is about two thirds of the volume of the crucible cavity 28;
s2, vacuumizing and washing gas: vacuumizing the crucible 17, the upper shell 22 and the lower shell by using a mechanical pump 25 and a diffusion pump 26, starting the mechanical pump 25, vacuumizing to be below 5Pa, filling high-purity inert protective gas, and vacuumizing to be below 5Pa, and repeating the operation for 3 times to ensure that the oxygen content in all the shells is lower than 10 ppm; the vacuumizing and the gas washing are used for reducing the oxygen content and preventing the metal from being heated and oxidized;
s3, high vacuum pumping and air inflation: turn on the diffusion pump 26 and pump high vacuum to 5X 10-3Below Pa, and filling high-purity inert protective gas;
s4, induction heating: setting heating parameters of a heater 18 (adopting an induction heater) according to the melting point of the raw material to be heated, monitoring the temperature in the crucible 17 in real time through a thermocouple arranged in the crucible 17, and preserving the heat for about 20 minutes after the metal material is completely melted;
s5, particle preparation: introducing high-purity inert protective gas through a crucible gas inlet pipe 30 arranged on the upper shell 22 and extending into the crucible 17, and generating back pressure in the crucible 17 to promote the molten metal to fill the central hole at the bottom of the crucible 17; cooling circulating water is introduced into the giant magnetostrictive actuator, an excitation current signal with a certain frequency is input, the giant magnetostrictive rod 4 generates downward displacement, and the molten metal is transmitted to the area near the central hole by the transmission rod 12 connected with the giant magnetostrictive rod 4 and the microporous gasket 23 arranged below the transmission rod 12, so that the molten metal is sprayed out from the bottom of the central hole to form uniform liquid drops 19;
s6, particle collection: the droplets 19 are dropped through an annular drop tube 20 and the uniform spherical metal particles are collected by a collecting tray 21 provided at the bottom of the lower housing.
The method is based on the giant magnetostrictive principle, and utilizes the unique performance of the giant magnetostrictive material to use the giant magnetostrictive micro-displacement driver for driving the ejection of micro liquid drops. The driver has the advantages of large expansion strain, high efficiency, accuracy, high response speed, long service life and the like, can eject liquid drops with smaller size and smaller particle size dispersity, and has better stability, thereby improving the production efficiency and quality of spherical microparticles.
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 (7)

1. A device based on super magnetostriction drive monodisperse micro-droplet sprays and solidifies characterized by, includes: the device comprises an upper shell (22), a lower shell, a giant magnetostrictive micro-displacement driver arranged above the outer part of the upper shell (22), a crucible (17) arranged in the upper shell (22) and a micro-particle collecting region arranged at the bottom of the lower shell, wherein the crucible (17) is arranged at the upper part of the micro-particle collecting region, and the giant magnetostrictive micro-displacement driver is positioned at the upper part of the crucible (17);
a crucible cavity (28) is arranged in the crucible (17) and is used for containing the melt (16); a transmission rod (12) connected with the giant magnetostrictive actuator is arranged in the crucible (17), the position where the transmission rod (12) is connected with the top of the crucible (17) is sealed by a dynamic sealing ring, the lower end of the transmission rod (12) is over against a central hole at the bottom of the crucible (17), and a microporous gasket (23) with a small hole is fixed at the bottom of the central hole through a screw; a heater (18) is arranged outside the crucible (17);
a crucible air inlet pipe (30) and a crucible air outlet pipe (29) which extend into the crucible (17) are arranged at the top of the upper shell (22), a diffusion pump (26) and a mechanical pump (25) are arranged on the side wall of the upper shell which is connected with the crucible (17), and a cavity air inlet valve (24) and a cavity air outlet valve (27) are also arranged on the upper shell (22);
the micro-particle collecting region comprises an annular drop tube (20) and a collecting disc (21), two sides of the annular drop tube (20) are respectively communicated with the upper shell (22) and the lower shell, and are used for allowing liquid drops (19) sprayed from small holes in the microporous gasket (23) to drop in the annular drop tube, the lower end of the annular drop tube (20) is over against the collecting disc (21), and the collecting disc (21) can collect particles by rotating discs with different sizes;
the giant magnetostrictive micro-displacement driver is used for driving the injection of micro liquid drops, a giant magnetostrictive rod (4) is arranged in the middle of the driver, the upper end of the transmission rod (12) is connected with the giant magnetostrictive rod (4), a permanent magnet (15), a magnetic yoke (14), an excitation coil (5) and a side magnetic wall (6) are sequentially arranged outside the giant magnetostrictive rod (4), end magnetic blocks (2) are arranged on the upper portion and the lower portion of the driver, a pre-compaction block (1) is arranged at the top of the end magnetic block (2) on the upper portion, and the upper end of the transmission rod (12) is connected with the end magnetic block (2) on the lower portion; the upper part and the lower part of the excitation coil (5) are respectively provided with an upper magnetizer (3) and a lower magnetizer (7); the permanent magnet (15), the end part magnetic conduction block (2), the upper magnetizer (3), the lower magnetizer (7), the side magnetic conduction wall (6) and the giant magnetostrictive rod (4) form a closed magnetic circuit; the lower end cover of the giant magnetostrictive micro-displacement driver is provided with a spring group (10) which is convenient for adjusting the pre-pressure; a gasket (9) is arranged between the top of the spring group (10) and the bottom end of the top of the transmission rod (12), and a pressure sensor (11) is arranged between the bottom of the spring group and the lower end cover.
2. The device for the giant magnetostrictive driving monodisperse micro-droplet jetting and solidification according to claim 1, wherein the microporous gasket (23) is made of a high temperature and corrosion resistant material.
3. The device for injecting and solidifying monodisperse micro-droplets based on giant magnetostriction driving as claimed in claim 1, wherein the diameter of the central hole of the crucible (17) is larger than the diameter of the small hole of the microporous gasket (23), and the diameter of the small hole of the microporous gasket (23) ranges from 0.5 μm to 500 μm;
the material of the microporous gasket (23) has a wetting angle with a melt (16) disposed within the crucible (17) of greater than 90 °.
4. The device for injecting and solidifying monodisperse micro-droplets based on giant magnetostriction driving is characterized in that the framework of the excitation coil (5) is designed into an annular hollow form, an annular closed cavity in the framework is used as a cooling chamber, and the giant magnetostriction rod (4) and the excitation coil (5) are in heat exchange with the framework;
cooling water enters the cooling chamber from a water inlet (8), directly exchanges heat with the framework, takes away heat transferred by the giant magnetostrictive rod (4) and the magnet exciting coil (5), and then is discharged from a water outlet (13);
the skeleton is in super magnetostrictive rod (4) with between excitation coil (5), it is isolated excitation coil (5) produce the heat to the transmission of super magnetostrictive rod (4), make excitation coil (5) with super magnetostrictive rod (4) obtain quick abundant cooling, effective control the deformation of super magnetostrictive rod (4).
5. The device for the giant magnetostrictive driven monodisperse microdroplet spraying and solidification based on claim 1, characterized in that the giant magnetostrictive rod (4), the transmission rod (12), the central hole of the crucible (17), the small hole of the microporous gasket (23) and the annular drop tube (20) are located on the same axis.
6. The device for injecting and solidifying monodisperse micro-droplets based on giant magnetostriction driving is characterized in that at least one thermocouple is arranged inside the upper shell (22), a probe used for monitoring the temperature on the thermocouple extends into the melt (16) inside the crucible (17) during the experiment, and the temperature of the melt (16) in the crucible (17) is measured.
7. The method for the ejection and solidification of monodisperse microdroplets based on giant magnetostriction driving according to any one of claims 1 to 6, wherein the method comprises the following steps:
s1, charging: putting a metal material to be melted into a crucible cavity (28) of a crucible (17) arranged in an upper shell (22) and then sealing; wherein the loading amount of the metal material loaded into the crucible cavity (28) is two thirds of the volume of the crucible cavity (28);
s2, vacuumizing and washing gas: vacuumizing the crucible (17), the upper shell (22) and the lower shell by using a mechanical pump (25) and a diffusion pump (26), opening the mechanical pump (25) to vacuumize to below 5Pa, filling high-purity inert protective gas, and vacuumizing to below 5Pa, wherein the operation is repeated for 3 times to ensure that the oxygen content in all the shells is below 10 ppm;
s3, high vacuum pumping and air inflation: the diffusion pump (26) is turned on to pump high vacuum to 5 x 10-3Below Pa, and filling high-purity inert protective gas;
s4, induction heating: setting heating parameters of a heater (18) according to the melting point of the raw material to be heated, monitoring the temperature in the crucible (17) in real time through a thermocouple arranged in the crucible (17), and preserving the temperature for 20 minutes after the metal material is completely melted;
s5, particle preparation: introducing high-purity inert protective gas through a crucible gas inlet pipe (30) arranged on the upper shell (22) and extending into the crucible (17), and generating back pressure in the crucible (17) to promote molten metal to fill a central hole at the bottom of the crucible (17); cooling circulating water is introduced into the giant magnetostrictive actuator, an excitation current signal with a certain frequency is input, the giant magnetostrictive rod (4) generates downward displacement, and the molten metal in the area near the central hole is transmitted to the molten metal by a transmission rod (12) connected with the giant magnetostrictive rod (4) and a microporous gasket (23) arranged below the transmission rod (12), so that the molten metal is sprayed out from the bottom of the central hole to form uniform liquid drops (19);
s6, particle collection: the liquid drops (19) drop through an annular drop tube (20), and uniform spherical metal particles are collected by a collecting tray (21) arranged at the bottom of the lower shell.
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CN1899732A (en) * 2005-07-21 2007-01-24 北京有色金属研究总院 Method and device for preparing precision welding ball
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