阅读说明：本技术 电子束辅助真空电扫超音速沉积喷枪 (Electron beam assisted vacuum electric scanning supersonic speed deposition spray gun ) 是由 周留成 何卫锋 延黎 柳平 苗卓广 林敏� 罗思海 李玉琴 安志斌 于 2020-12-15 设计创作，主要内容包括：本发明公开了一种电子束辅助真空电扫超音速沉积喷枪,包括冷喷头、高能电子束发射器以及电子束控制装置,所述电子束控制装置安装于高能电子束发射器出射口处用于控制电子束的发射方向,以使得电子束与冷喷头喷射方向汇聚于一点。本发明通过高能电子束发射器可对基体和粉末束中的粉末粒子加热,通过温度控制可使得粉末粒子在固态状态下提高温度,提高固体粒子的塑性,使的基体表面温度提高甚至熔融,以降低固体粒子沉积需要的临界速度,或者可使得粉末粒子加热后在相变条件下沉积,实现热喷涂,同时粉末粒子沉积过程对基体形成夯实、强化效应,进一步提高沉积层结合强度；而且利于控制整个喷涂介质的方向,防止喷涂过程的飞溅和发散现象。(The invention discloses an electron beam assisted vacuum electro-sweeping supersonic deposition spray gun which comprises a cold spray head, a high-energy electron beam emitter and an electron beam control device, wherein the electron beam control device is arranged at the exit of the high-energy electron beam emitter and used for controlling the emission direction of an electron beam so as to enable the injection directions of the electron beam and the cold spray head to converge at one point. The invention can heat the base body and the powder particles in the powder beam through the high-energy electron beam emitter, can improve the temperature of the powder particles in a solid state through temperature control, improve the plasticity of the solid particles, improve the surface temperature of the base body and even melt the base body so as to reduce the critical speed required by the deposition of the solid particles, or can ensure that the powder particles are deposited under the phase change condition after being heated to realize thermal spraying, and simultaneously, the powder particle deposition process forms tamping and strengthening effects on the base body so as to further improve the bonding strength of the deposition layer; but also is beneficial to controlling the direction of the whole spraying medium and preventing the splashing and scattering phenomena in the spraying process.)

1. An electron beam assisted vacuum electro-sweeping supersonic deposition spray gun is characterized in that: the electron beam control device is arranged at an exit of the high-energy electron beam emitter and used for controlling the emission direction of the electron beams so as to enable the injection directions of the electron beams and the cold spray head to converge at one point.

2. The electron beam assisted vacuum electro-swept supersonic deposition lance of claim 1, wherein: the cold spray head comprises a powder feeding device, an electrostatic generating device, a Laval nozzle, a nozzle and a deflection coil I which are sequentially arranged, wherein the electrostatic generating device is used for enabling powder particles sent out from the powder feeding device to be charged, high-pressure gas is introduced into the Laval nozzle and used for accelerating the charged particles and enabling the accelerated particles to be sprayed out through the nozzle, and the deflection coil is arranged at the outlet end of the nozzle and used for controlling the spraying direction of charged particle beams.

3. The electron beam assisted vacuum electro-swept supersonic deposition lance of claim 2, wherein: the electron beam control device is a deflection coil II which is arranged at the exit of the high-energy electron beam emitter and is used for controlling the electron beam so that the electron beam is converged at one point with the charged particle beam sprayed by the nozzle in real time.

4. The electron beam assisted vacuum electro-swept supersonic deposition lance of claim 2, wherein: the cold spray head also comprises a heating device which is arranged on the outlet side of the powder feeding device and used for heating the particles.

5. The electron beam assisted vacuum electro-swept supersonic deposition lance of claim 4, wherein: the cold spray head further comprises an accelerating device, the accelerating device is arranged on the outlet side of the Laval nozzle, and the accelerating device is provided with an accelerating electric field and used for accelerating the charged particles and enabling the accelerated particles to be sprayed out through the nozzle.

6. The electron beam assisted vacuum electro-swept supersonic deposition lance of claim 5, wherein: the outlet end of the Laval nozzle is provided with a primary magnetic lens used for focusing charged particle beams, and the accelerating device is arranged on the outlet end side of the primary magnetic lens.

7. The electron beam assisted vacuum electro-swept supersonic deposition lance of claim 2, wherein: the nozzle is externally connected with a secondary magnetic lens for focusing particle beams, and the deflection coil I is arranged at the outlet end of the secondary magnetic lens.

8. The electron beam assisted vacuum electro-swept supersonic deposition lance of claim 6, wherein: the cold spray head further comprises a shell, the powder feeding device is connected to the top of the shell and used for feeding powder into the shell, the nozzle is arranged at the bottom of the shell and is vertically opposite to the outlet end of the powder feeding device, and the shell is provided with an air inlet used for introducing high-pressure gas into the Laval nozzle.

9. The electron beam assisted vacuum electro-swept supersonic deposition lance of claim 8, wherein: the shell is also provided with an air pumping hole for pumping air so as to form a near vacuum environment in the shell.

10. The electron beam assisted vacuum electro-swept supersonic deposition lance of claim 8, wherein: the utility model discloses a particle beam of Laval spray tube, including shell, powder delivery device, accelerating device, nozzle, insulating board, upper chamber, lower chamber, Laval spray tube, upper chamber and lower chamber, the shell inner chamber is separated for upper chamber, middle part cavity and lower chamber through the insulating board, the Laval spray tube sets up in the middle part cavity and makes upper chamber and lower chamber intercommunication, powder delivery device bottom has the powder delivery pipe that is used for guiding the particle flow, powder delivery pipe extends to Laval spray tube entrance point through last chamber downwardly, heating device sets up in the upper chamber, accelerating device sets up to be used for making Laval spray tube spun particle beam with higher speed in the lower chamber, the nozzle sets up and makes the particle beam after accelerating.

Technical Field

The invention relates to the technical field of surface spraying, in particular to an electron beam assisted vacuum electric sweeping supersonic speed deposition spray gun.

Background

The existing supersonic cold spraying technology generally utilizes compressed gas to generate supersonic airflow through a convergent-divergent Laval tube, powder is axially conveyed into the supersonic airflow to form gas-solid dual-phase flow, and the gas-solid dual-phase flow is accelerated to impact a substrate in a completely solid state and generate large plastic deformation to deposit on the surface of the substrate to form a coating. In order to improve the deposition efficiency of the powder, the powder particles are usually heated by air heating, and the heating mode can only meet the heating requirement of the powder particles in a solid state and cannot adapt to different spraying working conditions.

Accordingly, there is a need for an electron beam assisted vacuum electro-swept supersonic deposition gun such that the powder can be switched between solid and molten states, thereby enabling switching between cold and thermal spraying.

Disclosure of Invention

In view of the above, the present invention provides an electron beam assisted vacuum electro-swept supersonic deposition spray gun, which uses a high-energy electron beam emitter as an auxiliary device for heating a substrate and a powder beam, so that powder can be deposited on the surface of the substrate at a higher temperature, thereby improving the deposition efficiency of spraying, even realizing thermal spraying and deposition based on phase change, further realizing the switching between cold spraying and thermal spraying, improving the application range of the spray gun, and simultaneously, high-speed powder jet forms tamping and strengthening effects on the substrate, and improves the deposition strength of materials, even integrally formed.

The electron beam auxiliary vacuum electric scanning supersonic deposition spray gun comprises a cold spray head, a high-energy electron beam emitter and an electron beam control device, wherein the electron beam control device is arranged at an exit of the high-energy electron beam emitter and used for controlling the emission direction of an electron beam so as to enable the injection directions of the electron beam and the cold spray head to converge at one point.

Further, the cold spray head comprises a powder feeding device, an electrostatic generating device, a laval nozzle, a nozzle and a deflection coil I which are sequentially arranged, the electrostatic generating device is used for enabling powder particles sent out from the powder feeding device to be charged, high-pressure gas is introduced into the laval nozzle and used for enabling the charged particles to be accelerated and enabling the accelerated particles to be sprayed out through the nozzle, and the deflection coil is arranged at the outlet end of the nozzle and used for controlling the spraying direction of charged particle beams.

Furthermore, the electron beam control device is a deflection coil II which is arranged at the exit of the high-energy electron beam emitter and is used for controlling the electron beam so that the electron beam is converged at one point with the charged particle beam sprayed by the nozzle in real time.

Further, the cold spray head also comprises a heating device which is arranged on the outlet side of the powder feeding device and used for heating the particles.

Further, the cold spray head further comprises an accelerating device, the accelerating device is arranged on the outlet side of the Laval nozzle, and the accelerating device is provided with an accelerating electric field and used for accelerating the charged particles and enabling the accelerated particles to be sprayed out through the nozzle.

Further, a first-order magnetic lens for focusing the charged particle beams is arranged at the outlet end of the laval nozzle, and the accelerating device is arranged on the outlet end side of the first-order magnetic lens.

Furthermore, a secondary magnetic lens for focusing the particle beams is externally connected with the nozzle, and the deflection coil I is arranged at the outlet end of the secondary magnetic lens.

Further, the cold spray head further comprises a shell, the powder feeding device is connected to the top of the shell and used for feeding powder into the shell, the nozzle is arranged at the bottom of the shell and is vertically opposite to the outlet end of the powder feeding device, and an air inlet used for introducing high-pressure gas into the Laval nozzle is formed in the shell.

Furthermore, the shell is also provided with an air pumping hole for pumping air so as to form a near vacuum environment in the shell.

Further, the casing inner chamber is separated for last cavity, middle part cavity and lower cavity through the insulation board, the laval spray tube sets up in the middle part cavity and makes last cavity and lower cavity intercommunication, it has the powder delivery pipe that is used for guiding the particle flow to send powder device bottom, send the powder pipe to extend to laval spray tube entrance point downwards through last cavity, heating device sets up in last cavity, accelerating device sets up to be used for making laval spray tube spun particle beam with higher speed in lower cavity, the nozzle sets up and makes the particle beam after accelerating spout through the nozzle in lower cavity bottom, the air inlet communicates in middle part cavity or lower part cavity.

The invention has the beneficial effects that:

the invention can heat the powder particles in the matrix and the powder beam through the high-energy electron beam emitter, and further control the heating temperature of the matrix material and the powder particles by controlling the energy of the high-energy electron beam so as to control the deposition state of the powder particles on the surface of the matrix material; or the powder particles can be heated to form a molten state, so that thermal spraying is realized, and the application range of the spray gun is improved; in the thermal spraying process, solid powder particles can be heated to be in a molten state at the surface of the substrate or close to the surface of the substrate, and in addition, the direction of the whole spraying medium can be controlled by utilizing the magnetic focusing effect, so that the splashing and divergence phenomena caused by direct spraying are prevented; in addition, the structure can also realize the expanded function of welding or additive manufacturing, the powder and the base material can be heated simultaneously when in work, so that the powder is deeply and densely combined under the action of kinetic energy and partially or completely changed in structure under the action of total energy in the process of bombarding the base material, a micro-layer integrated structure is formed, and meanwhile, the high-energy bombardment effect of the micro-powder forms the tamping and micro-shot blasting strengthening effect, so that the bonding surface of a deposition layer and the performance of the whole are further enhanced;

according to the invention, the spraying powder is converted into the charged particle beam and accelerated by the accelerating electric field, the whole device can accelerate the particles to a preset speed through a smaller space, the size of the spray gun is reduced, the structural compactness of the spray gun is improved, higher spraying speed and energy can be obtained under the condition of lower spraying air pressure, and the focusing and accurate control of the spraying powder are realized, so that the spraying operation environment is improved, the spraying operation efficiency is improved, the acceleration process of the particle beam is more constant, the final speed of the particle beam is constant, the consistency of a coating sprayed on the surface of a substrate is better, and the spraying quality is improved; in addition, because the particle beams are charged, the adhesion performance of the particles is improved by applying opposite charges to the surface of the matrix, and the movement direction of the particle beams is changed by applying acting force to the particle beams through an electric field or a magnetic field, so that the jet direction of the charged particle beams is convenient to control;

according to the invention, the critical speed required by particle deposition is reduced by heating the particles, and when the temperature of the cold-sprayed particles is increased, the critical speed of deposition is reduced, the deposition efficiency is improved, the bonding strength is also increased, and a compact coating is favorably formed; and the direction of the charged particle beam can be accurately controlled by matching with the deflection coil so as to control the spraying direction, and the structure is simple, and the control on the particle beam is simple and accurate.

Drawings

The invention is further described below with reference to the figures and examples.

FIG. 1 is a schematic perspective view of a showerhead;

FIG. 2 is a schematic cross-sectional view of the showerhead;

FIG. 3 is a schematic view of a deflection yoke structure (horizontal deflection yoke);

FIG. 4 is a schematic structural view of a second embodiment of a cold spray head;

Detailed Description

As shown in the drawings, the electron beam assisted vacuum electro-swept supersonic deposition spray gun in the embodiment includes a cold spray head, a high-energy electron beam emitter 91, and an electron beam control device, where the electron beam control device is installed at an exit of the high-energy electron beam emitter for controlling an emission direction of an electron beam, so that the electron beam and a spray direction of the cold spray head converge at one point. As shown in fig. 1 and 2, the cold spray head is used for realizing cold spraying, so that the powder impacts the substrate in a complete solid state after being accelerated, and is subjected to large plastic deformation to be deposited on the surface of the substrate to form a coating; the high-energy electron beam emitter is the existing equipment which can be used for emitting high-energy electron beams, wherein the high-energy electron beams are formed by collecting electrons, have high energy density, are accelerated to a high speed under the action of a high-voltage accelerating electric field between a cathode and an anode in an electron gun, and form dense high-speed electron flow after the convergence of the lenses; the electron beam control device is used for controlling the emission direction of the high-energy electron beam, so that the high-energy electron beam and the powder beam sprayed by the cold spray head are always converged at a certain point, the powder particles in the powder beam can be heated through the structure, the heating temperature of the powder particles is controlled by controlling the energy of the high-energy electron beam, the state of the powder particles is controlled, the temperature of the powder particles can be increased in a solid state through temperature control, the plasticity of the solid particles is improved, the critical speed required by the deposition of the solid particles is reduced, or the powder particles can be heated to form a molten state, thermal spraying is realized, the solid powder particles can be heated to be in the molten state at the surface of the base body or close to the surface of the base body in the thermal spraying process, the direction of the whole spraying medium is favorably controlled, and the splashing and divergence phenomena caused; in addition, the structure can also realize the expansion function of welding, and can heat the powder and the base material simultaneously when in work, so that the powder is deeply and densely combined under the action of kinetic energy and realizes partial or complete tissue transformation under the action of total energy in the process of bombarding the base material to form a micro-layer integrated structure, and simultaneously, the micro-powder is subjected to high-energy bombardment effect to form tamping and micro-shot blasting strengthening effect, thereby further strengthening the bonding surface of a deposition layer and the performance of the whole;

in this embodiment, the cold spray head includes a powder feeding device 10, an electrostatic generating device 20, a laval nozzle 81, a nozzle 40, and a deflection coil i 60, which are sequentially disposed, the electrostatic generating device is configured to charge powder particles sent out from the powder feeding device, a high-pressure gas is introduced into the laval nozzle to accelerate the charged particles and eject the accelerated particles through the nozzle, and the deflection coil is disposed at an outlet end of the nozzle to control an ejection direction of the charged particle beam. Referring to fig. 2, the powder feeding device has a cylindrical housing, a powder feeding port is formed in the top of the housing, a powder outlet is formed in the bottom of the housing opposite to the powder feeding port, the electrostatic generating device is installed in an inner cavity of the powder feeding device, the electrostatic generating device mainly generates static electricity, outputs a single polarity, such as positive or negative polarity, and can adjust output voltage, in this embodiment, the electrostatic generating device includes a high-voltage discharge electrode arranged in the inner cavity of the powder feeding device and an insulator arranged below the electrode, a plurality of vertical holes are arranged on the insulator in an array manner, and the electrostatic generating device has an existing structure, which is not described in detail; the Laval nozzle is matched with high-pressure airflow for use, wherein the high-pressure airflow can be synchronously sent into the nozzle through the powder sending device or can be independently fed into the nozzle, the Laval nozzle is made of an insulating material, the front half part of the Laval nozzle is contracted to a narrow throat from big to small in the middle, the narrow throat is outwards expanded from small to big, and the gas in the nozzle flows into the front half part of the nozzle under high pressure and escapes from the rear half part after passing through the narrow throat. The structure can change the speed of the gas flow due to the change of the jet cross section area, so that the particle beam is accelerated to reach sonic speed or supersonic speed; referring to fig. 2 and 3, the deflection yoke is composed of a pair of horizontal coils and a pair of vertical coils, each pair of coils is composed of two windings connected in series or in parallel with each other with the same number of turns and the same shape. When certain currents are respectively supplied to the horizontal coil and the vertical coil, the two pairs of coils respectively generate certain magnetic fields. The horizontal coil generates a pincushion field, the vertical coil generates a barrel-shaped field, the jetting direction of the charged particle beam is controlled by the cooperation of the horizontal coil and the barrel-shaped field, so that the particle beam realizes horizontal scanning and vertical scanning on the surface of the matrix, the direction of the charged particle beam is accurately controlled, controllable scanning and spraying are realized, and the production efficiency is greatly improved; powder particles are fed in through a powder feeding device in the structure, the powder particles form charged particles after passing through an electrostatic generating device, the charged particles are accelerated through a Laval nozzle to enable the particle beam speed to quickly reach the critical speed of the particles, particularly to reach the sonic speed or the supersonic speed, the sonic speed or the supersonic speed particle beam is sprayed out through a nozzle to impact the surface of a base body and generate larger plastic deformation to be deposited on the surface of the base body to form a coating, the structure converts spraying powder into the charged particle beam, and a deflection coil applies acting force to the particle beam to change the motion direction of the particle beam, so that the precise control of the spraying direction is realized, and the controllability of the distribution of the coating is improved; the control structure is simple, the control on the particle beams is simple and accurate, the control precision is high, and the scanning speed is high; in addition, since the particle beam is charged, the adhesion property of the particles can be improved by applying an opposite charge to the surface of the substrate.

In this embodiment, the electron beam control device is a deflection coil ii 92 installed at the exit of the high-energy electron beam emitter, and the deflection coil ii is used for controlling the electron beam so that the electron beam converges with the charged particle beam ejected from the nozzle at one point in real time. The deflection coil II is similar to the deflection coil I in structure, the deflection coil I is used for controlling powder particle scanning, and the deflection coil II controls electron beams to follow the powder particle dynamic scanning, so that the powder particle beams and the electron beams are converged at one point all the time, and preferably the powder particle beams and the electron beams are converged at the surface of the substrate.

In this embodiment, the cold spray head further includes a heating device 50 disposed at an outlet side of the powder feeding device for heating the particles. Heating device can set up in powder feeding device department, static electricity generating device or nozzle department, heating device's specific position that sets up can be adjusted according to actual structure, heating device can be electric heating device or laser heating device, the preferred electric heating device in this embodiment, electric heating device installs in the position of powder feeding device meal outlet, a heating for the particle, reduce the critical speed that particle deposit needs through the heating to the particle, when the particle temperature of cold spraying rises, realize that the critical speed of deposit reduces, deposition efficiency improves thereupon, bonding strength also increases, do benefit to and form fine and close coating.

In this embodiment, the outlet end of the laval nozzle is provided with a primary magnetic lens 82 for focusing the charged particle beam, and the accelerating device is provided on the outlet end side of the primary magnetic lens. The outlet end of the first-level magnetic lens is connected with the nozzle, the magnetic lens is provided with an axisymmetric magnetic field which can be generated by a solenoid, an electromagnet or a permanent magnet, the magnetic lens can converge the uniform-speed charged particle beams, the charged particle beams sprayed out of the Laval nozzle are converged and enter an accelerating electric field through the first-level magnetic lens, the precise centralized control of the jet direction of the charged particle beams is facilitated, and the spraying precision of the spray gun is improved.

In this embodiment, the powder feeding device has a powder feeding pipe 11 at the bottom for guiding the flow of particles, and the heating device is disposed around the powder feeding pipe. Referring to fig. 2, the heating device is a spiral heating resistance wire, and two groups of spiral resistance wires with different diameters are arranged around the inside and the outside of the powder feeding pipe, so that the air temperature at the periphery of the powder feeding pipe can be uniformly heated, the temperature of particles can be uniformly increased, and the critical speed required by particle deposition can be reduced.

In this embodiment, the inner cavity at the bottom of the powder feeding pipe 11 is gradually reduced downwards to form a conical outlet. This configuration facilitates the aggregation of the powder and allows the powder fed into the laval nozzle to form a powder bundle.

In this embodiment, the cold spray head further includes a housing 70, the powder feeding device is connected to the top of the housing and used for feeding powder into the housing, the nozzle is arranged at the bottom of the housing and vertically faces to the outlet end of the powder feeding device, and the housing is provided with an air inlet 83 for introducing high-pressure gas into the laval nozzle. The air inlet can also be arranged on the powder feeding device, and a powder feeding port on the powder feeding device is also used as the air inlet, wherein the shell is made of insulating materials, the whole shell is of a cylindrical structure, and gas introduced from the air inlet enters the shell and then passes through the Laval nozzle to be used for accelerating particle beams; the shell is divided into an upper cavity and a lower cavity, the heating device is arranged in the upper cavity, the Laval nozzle is arranged in the lower cavity, and the powder feeding pipe 11 extends to the air inlet end of the Laval nozzle through the upper cavity;

referring to fig. 4, fig. 4 is another embodiment of a cold spray head, the cold spray head in fig. 4 is different from the cold spray head in fig. 2 in that an accelerating device and a secondary magnetic lens and an air suction port are additionally provided in fig. 4, and a housing of the cold spray head in fig. 4 is different from that in fig. 2;

referring to fig. 4, in this embodiment, the cold spray head further includes an accelerating device 30 disposed at an outlet side of the laval nozzle, and the accelerating device has an accelerating electric field for accelerating the charged particles and spraying the accelerated particles through the nozzle. The accelerating electric field is a uniform electric field which increases the speed of the charged particles after being shot into the accelerating device, the direction of the electric field is the same as the speed direction of the positively charged particles and is opposite to the speed direction of the negatively charged particles, and the accelerating device can be provided with a one-stage accelerating electric field or a multi-stage accelerating electric field, which is not described in detail; in the embodiment, the positive electrode and the negative electrode of the accelerating electric field are vertically opposite, through holes for particle beams to pass through are formed in the positive electrode and the negative electrode, the through holes are positioned right below the powder outlet of the powder feeding device, and the corresponding nozzles are opposite to the through holes in the positive electrode and the negative electrode; the initial speed of a particle beam entering an accelerating device is improved through the arrangement of a Laval nozzle, the charged particles are accelerated through the accelerating device, so that the particle beam speed quickly reaches the critical speed of the particles, particularly the supersonic speed or the hypersonic speed is achieved, the supersonic particle beam is sprayed out through a nozzle to impact the surface of a matrix, and large plastic deformation is generated to deposit on the surface of the matrix to form a coating, the spraying powder is converted into the charged particle beam by the structure and is accelerated through an accelerating electric field, the particles can be accelerated to the preset speed through a small space by the whole device, the size of a spray gun is reduced, the structural compactness of the spray gun is improved, the accelerating process of the particle beam is constant, the final speed of the particle beam is constant, the consistency of the coating sprayed on the surface of the matrix is; the final speed of particle beams is improved through the multi-stage acceleration of the Laval nozzle and the accelerating device, and higher spraying speed and energy can be obtained under the condition of lower spraying air pressure, so that the particle deposition efficiency and the bonding strength are improved.

In this embodiment, the nozzle is externally connected with a secondary magnetic lens 85 for focusing the particle beam, and the deflection coil i is mounted at an outlet end of the secondary magnetic lens. Referring to fig. 3, the nozzle is an opening formed at the bottom of the housing 70, and the outlet end of the nozzle is connected to a secondary magnetic lens 85, so that the particle beam accelerated by the electric field is converged again, and the particle beam is converged at one point precisely, thereby facilitating the direction control of the deflection coil.

In this embodiment, the housing further has a pumping hole 84 for pumping out gas to form a near vacuum environment inside the housing. The near vacuum environment is an approximately vacuum environment with a certain vacuum degree, gas introduced from the gas inlet of the near vacuum environment is accelerated by the particle beams through the Laval nozzle, wherein the air exhaust flow of the air exhaust opening is larger than the air intake flow of the gas inlet, the air exhaust opening can be arranged on the outlet side of the Laval nozzle and used for exhausting air flow sprayed out through the Laval nozzle, and the arrangement of the air exhaust opening can also provide the near vacuum environment for the accelerating device, so that the interference of the outside on the particle beams is reduced in the electric field accelerating process.

In this embodiment, the casing inner chamber is separated for upper chamber 71, middle part cavity 72 and lower cavity 73 through the insulation board, the laval nozzle sets up in the middle part cavity and makes upper chamber and lower cavity intercommunication, send the powder pipe to extend to laval nozzle entrance point downwards through the upper chamber, heating device sets up in the upper chamber, accelerating device sets up and is used for making laval nozzle spun particle beam with higher speed in the lower cavity, the nozzle sets up and makes the particle beam after accelerating spout through the nozzle in the lower cavity bottom, air inlet 83 communicates in middle part cavity or lower cavity. The shell can be an integrated cylindrical shell, an insulating plate is arranged in the shell to divide the internal space into a plurality of spaces, the shell in the embodiment is formed by axially splicing two split cylindrical shells, wherein the shell positioned below is divided into a middle cavity and a lower cavity through the insulating plate, the inner cavity of the shell positioned above is an upper cavity, the structure divides the interior of the shell into a plurality of functional areas through a plurality of cavities, each functional area is beneficial to independent installation of corresponding parts, functions of each area do not interfere with each other, and the stability and reliability of the spray gun are improved; the structure can heat the high-pressure gas introduced into the upper chamber through the heating device, improve the kinetic energy of the gas flow, and heat the powder particles by means of the gas, so that the effective heating of the powder particles is ensured and the overheating of the powder particles is also prevented; as shown in fig. 4, the gas introduced into the air inlet directly flows out through the laval nozzle and flows out through the air exhaust port, wherein the air exhaust flow of the air exhaust port should be greater than the air intake flow of the air inlet, wherein the air exhaust port is externally connected with a water ring vacuum pump, and the air inlet is externally connected with a compressor, so that a vacuum environment is formed in the casing.

Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.