Combined direct-current arc plasma powder manufacturing device

Abstract

The utility model relates to a combined type direct-current arc plasma pulverizing device, which belongs to the technical field of plasma application and comprises a plasma torch, a plasma power supply, a powder feeding section and an atomization reactor which are sequentially mounted, the upper part of the atomization reactor is conical, and a plurality of supersonic plasma spray guns are arranged along the normal direction of a conical surface; and high-temperature and high-speed plasma jet flow generated by the supersonic plasma spray gun is used for secondarily heating and crushing molten powder particles entering the plasma torch from the powder inlet section, so that the superfine spherical powder material is prepared. The equipment is simple in structure, the plasma torch, the supersonic plasma spray gun and the powder feeding system are mutually independent, the controllability is good, and the preparation of powder with small particle size, uniform distribution and high sphericity degree is realized.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of plasma application technology, specifically relates to a combined direct current arc plasma powder preparation device. BACKGROUND

[0002] With the wide application of additive manufacturing, powder metallurgy, surface spraying and other technologies, the demand for spherical powder is increasing day by day, and higher requirements for its performance are also put forward, such as composition, particle size, sphericity, oxygen content, bulk density, etc. At present, the commonly used powder preparation technologies include water atomization, gas atomization, electrode induction atomization and plasma atomization, among which gas atomization occupies a dominant position, accounting for about 70-80% of the market share. However, the gas consumption is huge, the powder sphericity is poor, and hollow powder and satellite powder are easily produced. Water atomization is not suitable for powder with high oxygen content requirement. Electrode induction atomization is difficult to scale up and is not suitable for industrial production. Although plasma atomization can produce powder with high sphericity and high bulk density, the particle size is relatively large. Therefore, there is an urgent need for a powder preparation method to solve the above problems to meet the growing market demand.

[0003] The spheroidization of powder is a two-process, i.e. phase transition and fragmentation of powder. The solid-phase powder particles are heated to become molten liquid phase, which may also be accompanied by thermal decomposition reaction. Then, under the impact of gas flow, they are broken into small liquid droplet particles, which are solidified into spherical shape under the action of surface tension during the cooling process. Due to the differences in material properties, the temperature and time conditions in the two transformation processes are different. Currently, the commonly used powder particle size range in the field of additive manufacturing is 15-53um (fine powder) and 53-150um (coarse powder). In order to improve the fine powder yield, domestic and foreign research institutions have carried out a lot of research work.

[0004] The patent CN 114192090A of Hefei Institute of Material Science of Chinese Academy of Sciences discloses a device for preparing zirconia based on direct current plasma torch. The device adopts a three-rod cathode and a ring-shaped anode structure, and utilizes rotating gas to constrain the arc rotation, which can obtain a larger hot zone, but the plasma jet velocity is relatively low, the impact and fragmentation effect on molten powder particles are limited, and small particle size powder particles cannot be obtained. Moreover, the powder raw material passes through the plasma arc region, affecting the stability of the plasma arc.

[0005] Patent CN 115740471A of Zhejiang Bauton Welding Technology Co., Ltd. discloses a kind of ultrasonic auxiliary plasma-arc composite atomization powder making equipment and powder making method, the device utilizes arc power between two wire feeding arc device and gives arc, melts wire and decomposes into liquid drop, ultrasonic vibration is applied on the nozzle of wire feeding device, liquid is broken, further refined to metal liquid drop using plasma jet, obtains metal powder after cooling.The method although helps to improve fine powder yield, but it is difficult to maintain stable arc discharge between two consumable wires, liquid particle size, powder particle size uniformity are difficult to guarantee.

[0006] Patent CN 116352096A applied by Nuclear Industry Southwest Physics Research Institute discloses a kind of plasma atomization and spheroidization device for preparing refractory metal spherical powder, the device utilizes multiple plasma torches arranged in circumferential direction to generate plasma jet as heat source to atomize and spheroidize wire entering guide pipe.The device process flow is simple, controllability is good, but only one melting and breaking process is completed for wire, spheroidization rate is not high enough. Practical new type content

[0007] To overcome the instability of prior art, poor uniformity, low fine powder yield and other deficiencies, the utility model provides a kind of combined direct current arc plasma powder making device, by supersonic plasma torch to the raw material that is melted in the descending process by plasma torch jet for secondary heating and breaking, realize the preparation of superfine spherical powder.

[0008] The technical scheme adopted by the utility model is: a kind of combined direct current arc plasma powder making device, including plasma torch, plasma power supply, powder inlet section, atomization reactor are sequentially connected from top to bottom, characterized by: the upper part of atomization reactor is conical, is provided with several supersonic plasma torches along the normal direction of conical surface, high-temperature high-speed plasma jet generated by supersonic plasma torch is used to melt the powder entering plasma torch jet from powder inlet section for secondary heating and breaking, to prepare superfine spherical powder material.

[0009] The combined direct current arc plasma powder making device, a working gas inlet and a rotating gas passage are provided on the cathode insulating seat.

[0010] The combined direct current arc plasma powder making device, the plasma torch includes a water-cooled anode electrode and a cathode electrode, and a cavity is formed between the anode electrode and the cathode electrode, which is in communication with the rotating gas passage and the gas inlet of the working gas.

[0011] The combined direct current arc plasma powder making device, the working gas of the plasma torch is one or any combination of argon, nitrogen, helium and hydrogen, and the gas flow is 2-10m 3 / h.

[0012] The powder feeding section center hole is conical, the included angle is α, -30°≤α≤30°; a plurality of powder feeding ports are arranged along the circumferential direction, the distance between the inlet end of the powder feeding port and the plasma torch anode electrode is A, 0≤A≤50mm, and the included angle with the horizontal plane is β, -10°≤β≤10°.

[0013] The powder feeding section center hole is conical, the included angle is α, -30°≤α≤30°; a plurality of powder feeding ports are arranged along the circumferential direction, the distance between the inlet end of the powder feeding port and the plasma torch anode electrode is A, 0≤A≤50mm, and the included angle with the horizontal plane is β, -10°≤β≤10°.

[0014] The powder feeding section center hole is conical, the included angle is α, -30°≤α≤30°; a plurality of powder feeding ports are arranged along the circumferential direction, the distance between the inlet end of the powder feeding port and the plasma torch anode electrode is A, 0≤A≤50mm, and the included angle with the horizontal plane is β, -10°≤β≤10°.

[0015] The powder feeding section center hole is conical, the included angle is α, -30°≤α≤30°; a plurality of powder feeding ports are arranged along the circumferential direction, the distance between the inlet end of the powder feeding port and the plasma torch anode electrode is A, 0≤A≤50mm, and the included angle with the horizontal plane is β, -10°≤β≤10°. 3 / h. Advantages

[0016] The combined direct current arc plasma powder preparation device has the advantages that the device structure is simple, the plasma torch, the supersonic plasma spray gun and the powder feeding system are independent of each other and have good controllability, the preparation of small-particle-size, uniformly distributed and high-sphericity powder can be realized through secondary crushing of the once-melted particle droplets. BRIEF DESCRIPTION OF DRAWINGS

[0017] Fig. 1 is a schematic view of a combined direct current arc plasma powder preparation device;

[0018] Figure 2 Fig. 2 is a schematic view of a powder feeding section structure;

[0019] Figure 3 Fig. 3 is a schematic view of a supersonic plasma spray gun installation;

[0020] Figure 4 Fig. 4 is a schematic view of a quenching device structure.

[0021] Reference numerals: 1 Plasma torch, 1-1 Plasma torch cathode, 1-2 Cathode insulation seat, 1-3 Working gas inlet, 1-4 Rotating gas channel, 1-5 Plasma torch anode, 1-6 Plasma torch jet, 1-7 Anode cooling jacket, 2 Plasma power supply, 3 Powder inlet section, 4 Atomizing reactor, 5 Supersonic plasma spray gun, 6 Spray gun power supply, 7 Spray gun jet, 8 Secondary atomized powder, 9 Insulation layer, 10 Primary atomized powder, 11 Powder inlet, 12 Quenching device, 13 Cavity, 14 Nozzle, 15 Cooling medium inlet. Detailed Implementation

[0022] To more clearly explain the technical solution of this utility model and enable those skilled in the art to accurately understand the technical solution and beneficial effects of this utility model, detailed explanations and descriptions will be provided below by way of embodiments. However, this utility model is not limited to these embodiments. The utility model will be further described below with reference to the accompanying drawings:

[0023] Example 1, refer to Appendix Figure 1 A combined DC arc plasma powder-making device includes a plasma torch 1, a plasma power supply 2, a powder inlet section 3, an atomizing reactor 4, a supersonic plasma spray gun 5, and a spray gun power supply 6. The plasma torch 1 consists of a plasma torch cathode 1-1, a cathode insulating base 1-2, a plasma torch anode 1-5, and an anode cooling jacket 1-7. The plasma torch cathode 1-1 and plasma torch anode 1-5 are respectively connected to the cathode and anode of the plasma power supply 2. A working gas inlet 1-3 is provided on the outer side of the cathode insulating base 1-2, and several rotating gas channels 1-4 are arranged axially inside, serving as the working gas flow channels for the plasma torch 1. A cavity 13 is formed between the plasma torch cathode 1-1 and the plasma torch anode 1-5, which, together with the rotating gas channels 1-4 on the cathode insulating base 1-2 and the working gas inlet 1-3, constitutes the working gas channel for the plasma torch 1. The working gas is one or a combination of argon, nitrogen, helium, and hydrogen, with a gas flow rate of 2-10 m³ / s. 3 / h. Working gas is introduced through working gas inlets 1-3. The plasma power supply 2 is turned on, with a working voltage of 20-200V and a working current of 50-800A. This generates a plasma jet 1-6 between the plasma torch cathode 1-1 and plasma torch anode 1-5, penetrating the working gas channel of the plasma torch and forming a high-energy fluid with high temperature, high speed, and high chemical activity at 2000-20000K. The powder inlet section 3 is located below the plasma torch 1, with a conical channel at its center and an included angle of α, -30°≤α≤30°, effectively preventing molten raw material particles from adhering to the inner wall of the channel. Several powder inlets 11 are distributed along the circumference of the powder inlet section 3, with the centerline of the powder inlet 11 forming an angle β with the horizontal plane, -10°≤β≤10° (e.g., ...). Figure 2The distance between the inlet of powder inlet 11 and the anode 1-5 of the plasma torch is A, 0≤A≤50mm, preferably 0≤A≤20mm. The raw material to be processed can be metallic or non-metallic, with a conveying rate of 20-500g / min. It is carried by a carrier gas from powder inlet 11 into the central cavity of the powder inlet section 3. The carrier gas is the same as or one of the working gases of the plasma torch 1, and the gas flow rate is 1-5m³ / min. 3 / h. Mixed with the downward-flowing plasma jets 1-6, the material is heated above its melting point. During this melting process, the raw material may also undergo pyrolysis or other chemical reactions, forming a primary atomized powder 10, which enters the inner cavity of the atomizing reactor 4. The atomizing reactor 4 adopts a jacketed water-cooled structure and has an internal insulation layer 9. The upper part of the atomizing reactor 4 has a conical structure, with several supersonic plasma nozzles 5 arranged along the normal direction of the conical surface. Each supersonic plasma nozzle 5 is connected to a nozzle power supply 6, with a working voltage of 1... The operating voltage is 0-100V, the working current is 50-500A, the angle between the axis of the supersonic plasma spray gun 5 and the center line of the primary atomized powder 10 is θ, 5°≤θ≤90°, preferably 10°≤θ≤45°, the distance between the center of the outlet of the supersonic plasma spray gun 5 and the center plane of the powder inlet 10 is B, 10mm≤B≤150mm, preferably 30mm≤B≤100mm, 10mm≤B*tanθ≤100mm, preferably 10mm≤B*tanθ≤60mm (e.g., ...). Figure 3 The working gas of the supersonic plasma spray gun 5 is one or a combination of argon, nitrogen, helium, and hydrogen, with a gas flow rate of 2-6 m³ / s. 3 At / h, working gas is introduced, and the spray gun power supply 6 is turned on, generating a high-temperature, high-speed supersonic jet 7 that impacts the primary atomized powder 10 from multiple directions. This secondary heating and crushing of the molten liquid powder particles in the primary atomized powder 10 produces smaller-diameter liquid particles 8. These particles cool during their descent and gradually solidify under surface tension, forming spherical solid particles, which can then be collected to obtain the product. In this process, the plasma torch 1, the supersonic plasma spray gun 5, and the powder feeding system are independent of each other, offering good controllability. Through the secondary crushing of the primary molten particle droplets, materials with small particle size, uniform distribution, and high sphericity can be prepared.

[0024] Example 2, see attached document Figure 4The difference between this embodiment and embodiment 1 is that a rapid cooling device 12 is provided below the atomizing reactor 4. The rapid cooling device 12 is a jacketed water-cooled structure, forming a cavity 13, which is connected to the cooling medium inlet 15. The cooling medium is a gaseous or liquid substance that does not chemically react with the raw material to be processed. Several cooling medium nozzles 14 are distributed along the circumference on the inner side of the cavity 13 for rapidly cooling the secondary atomized powder 8. The cooling rate is one million degrees per second. This is used to prepare materials with special requirements for cooling speed, such as the process of preparing zirconium oxide by plasma decomposition of zirconium silicate. A reverse reaction occurs during the cooling process, so rapid cooling is necessary.

[0025] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading this application specification, they can still modify or make equivalent substitutions to the specific implementation of this utility model, but these modifications or changes do not depart from the protection scope of the claims of this utility model application.

Claims

1. A combined direct current arc plasma powder production device, comprising a plasma torch, a plasma power supply, a powder feeding section, and an atomization reactor connected in sequence from top to bottom, characterized in that: The upper part of the atomization reactor is provided with several supersonic plasma torches, and the plasma torches are arranged above the powder feeding section.

2. A combined DC arc plasma powder production device according to claim 1, characterized in that The cathode insulation seat is provided with a working gas inlet and a rotating gas channel.

3. The combined DC arc plasma powder production device according to claim 1, characterized in that The plasma torch comprises a water-cooled anode electrode and a cathode electrode, and a cavity is formed between the anode electrode and the cathode electrode, and the cavity is communicated with the rotating gas channel and the gas inlet of the working gas.

4. The combined DC arc plasma powder production device according to claim 1, characterized in that The central hole of the powder feeding section is conical, and the included angle is α, -30°≤α≤30°; a plurality of powder feeding ports are arranged in the circumferential direction, the distance between the inlet end of the powder feeding port and the anode electrode of the plasma torch is A, 0≤A≤50mm, and the included angle with the horizontal plane is β, -10°≤β≤10°.

5. The combined DC arc plasma powder production device according to claim 1, characterized in that The atomization reactor adopts a jacket water cooling structure, and the upper part is conical; a plurality of supersonic plasma torch mounting holes are arranged on the conical surface along the normal direction, the axis of the mounting hole is consistent with the normal direction of the conical surface, and the included angle between the axis of the mounting hole and the jet axis of the plasma torch is θ, 5°≤θ≤90°; the distance between the center of the outlet of the supersonic plasma torch and the center plane of the powder feeding port is B, 10mm≤B≤150mm, and 10mm≤B×tanθ≤100mm.

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