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CN-115635092-B - Method and device for preparing ultrafine powder by taking strip as pulse discharge electrode

CN115635092BCN 115635092 BCN115635092 BCN 115635092BCN-115635092-B

Abstract

The invention provides a method and a device for preparing ultrafine powder by taking a strip as a pulse discharge electrode. The device specifically comprises a pulse power supply generator, a first electrode, a second electrode, an electrode driving assembly and a discharge medium, wherein the first electrode is a strip-shaped consumable electrode, the second electrode is a consumable electrode or a non-consumable electrode, and the first electrode and the second electrode are in driving connection through the electrode driving assembly so as to form a powder making space. The invention adopts the metal strip or the alloy strip as the discharge electrode, and realizes the continuous preparation of the powder by the stable strip feeding of the component. In the process of preparing the powder by the pulse discharge of the strip, the recast layer which is repeatedly melted and solidified is not existed, and the powder is formed completely, so the energy utilization rate, the powder yield and the production efficiency are greatly improved. Further, the composition of the strip material is more uniform than that of the bulk electrode, so that powder having a uniform composition can be prepared. The superfine metal powder obtained by the invention has high sphericity, uniform shape and smooth surface, and no obvious satellite powder, special-shaped powder and impurities.

Inventors

  • ZHANG TAO
  • LI RAN
  • Liu Chekai

Assignees

  • 北京航空航天大学

Dates

Publication Date
20260512
Application Date
20221104

Claims (4)

  1. 1. The device for continuously preparing ultrafine powder by using the strip pulse discharge electrode is characterized by comprising a pulse power supply generator, a first electrode, a second electrode, an electrode driving assembly and a discharge medium, wherein the pulse power supply generator is arranged outside a cavity, the first electrode, the second electrode, the electrode driving assembly and the discharge medium are arranged in the cavity, the first electrode is a consumable electrode, the second electrode is a consumable electrode or a non-consumable electrode, the consumable electrode and the non-consumable electrode are connected with the pulse power supply generator, the electrode driving assembly is in driving connection with the first electrode and/or the second electrode so as to form a powder preparation space between the first electrode and the second electrode, the powder preparation space is filled with the discharge medium, and the consumable electrode is subjected to the action of pulse plasma generated by the pulse power supply generator so as to form ultrafine metal powder; The first electrode is made of strip metal or strip alloy, and the second electrode is made of rod-shaped or block-shaped conductive material; the strip-shaped first electrode has a width of 1-200mm and a thickness of 10-100 μm, the rod-shaped second electrode has a diameter of 1-100mm, and the block-shaped second electrode has a length of 1-100mm, a width of 1-50mm and a thickness of 1-10mm; when the electrode driving assembly drives the first electrode and the second electrode to form a powder making space, the distance between the two electrodes is 0-3mm; the pulse power supply parameters are that the frequency is 500-10000000 Hz, the discharge current is 0.1-1000A, and the pulse width is 0.1-50 mu s; The device utilizes the motion effect between the electrodes to make the pulse plasma generated by the pulse power supply bombard the electrodes, And simultaneously, impact force generated when the discharge medium breaks down causes physical explosion of a melting area, and molten metal drops of the strip-shaped consumable electrode are completely thrown out of the melting tank without forming a recast layer.
  2. 2. The apparatus for continuously preparing ultra-fine powder using a pulse discharge electrode for strip material as set forth in claim 1, wherein the driving form of the electrode driving assembly comprises feeding, horizontal rotation, vibration or reciprocal translation.
  3. 3. The apparatus for continuously preparing ultra-fine powder using a pulsed discharge electrode for strip material as claimed in claim 1, wherein the discharge medium comprises a liquid and/or a gas.
  4. 4. A method for continuously preparing ultrafine powder by using the device of any one of claims 1-3, which is characterized by comprising the following steps of setting pulse power supply parameters, driving a first electrode and/or a second electrode to move by using an electrode driving assembly, bombarding the surface of a consumable electrode by pulse plasmas generated by a pulse power supply generator to enable the consumable electrode to be molten to form a molten pool, and simultaneously, enabling a discharge medium between the electrodes to be broken down by pulse voltages applied to the electrodes, and enabling metal liquid drops melted by the consumable electrode to be thrown out of the molten pool through physical explosion caused by discharge points when the interelectrode pressure and the temperature of the electrodes are suddenly increased, and then enabling the metal liquid drops to be cooled and solidified in the discharge medium to form spherical powder under the action of surface tension.

Description

Method and device for preparing ultrafine powder by taking strip as pulse discharge electrode Technical Field The invention belongs to the technical field of metal powder materials, and particularly relates to a method and a device for preparing ultrafine powder by taking a strip as a pulse discharge electrode. Background With the continuous development of industrial technology, there is an increasing demand for metal powder materials. The existing method for preparing the metal powder material mainly comprises a mechanical method, a physical and chemical method and the like, but the powder preparation particle size of the metal powder material is limited, and the metal powder material is difficult to prepare any particle size powder within the range of 1-100 microns, and particularly ultrafine sphere powder with the particle size smaller than 10 microns is difficult to prepare. The pulse discharge method is a process for machining by using electric energy, and is commonly called as electric discharge machining. When the pulse discharge method is used for processing, the tool is not contacted with the workpiece, but the metal material is gradually etched away by utilizing the local and instantaneous high temperature generated during the discharge by the pulse spark discharge generated continuously between the tool and the workpiece, and the pulse discharge method can be used for preparing conductive materials such as aluminum alloy, copper alloy, stainless steel, nickel-based superalloy, iron-based amorphous alloy, silicon and the like. During pulse discharge processing, the etched material is cooled and solidified in a discharge medium, and fine powder is finally formed under the action of surface tension. The powder prepared based on the pulse discharge method has the characteristics of good sphericity, little or no satellite powder and the like, and promotes the wide application and rapid development of the powder in the field of preparing powder materials. In the prior art, the device for preparing the powder by the pulse discharge method mainly comprises a rod-shaped device and an oscillating barrel device. However, the rod-shaped electrode has low powder preparation efficiency of about 1g/h, and can not meet the requirements of industrial production, and is generally used for experimental research. The barreled oscillating device can improve production efficiency by increasing the discharge point at the same time, but the powder particle size distribution range is wide, the superfine powder proportion is low, and the requirement is difficult to meet. In addition, the powder making process of the device has some problems, such as that when the block metal is used as a pulse discharge electrode, more than 50% of molten metal is repeatedly melted and solidified to form a recast layer instead of powder, so that a large amount of energy is consumed, the discharge electrode material is in a block shape, the sizes of crystal grains/crystal boundaries of different components in the block are generally larger than the particle size of the superfine powder, and the prepared superfine powder is uneven in component. Therefore, how to improve the energy utilization rate in the pulverizing process and achieve the uniformity of the components of the superfine powder by continuous pulverizing is a technical problem that needs to be solved by those skilled in the art. Disclosure of Invention The invention aims to provide a method for continuously preparing ultrafine metal powder, which can continuously prepare ultrafine spherical metal powder by arranging a pulse power generator arranged outside a cavity, a first electrode, a second electrode, an electrode driving assembly and a discharge medium which are arranged in the cavity, and has the effects of simple equipment and low preparation safety and energy consumption. The superfine metal powder prepared by the device has high sphericity, uniform shape, smooth surface, particle size ranging from 0.5 to 30 mu m and high powder preparation efficiency reaching 80g/h. The invention provides a device for continuously preparing ultrafine powder by taking a strip as a pulse discharge electrode, which comprises a pulse power generator, a first electrode, a second electrode, an electrode driving assembly and a discharge medium, wherein the pulse power generator is arranged outside a cavity, the first electrode is a consumable electrode, the second electrode is a consumable electrode or a non-consumable electrode, the first electrode, the second electrode, the electrode driving assembly and the discharge medium are connected with the pulse power generator in a driving way, the electrode driving assembly is connected with the first electrode and/or the second electrode in a driving way so as to form a powder preparation space between the first electrode and the second electrode, the discharge medium is filled in the powder preparation space, and the consumable electrode acts on p