Method for producing deformed particles of radio-absorbing powder

Abstract

FIELD: powder metallurgy.SUBSTANCE: invention relates to production of deformed particles of radio-absorbing powders. It can be used in mechanical engineering, aerospace engineering, automotive industry, energy, construction, oil and gas industry and other areas of the economy. Particles of the original radio-absorbing powder are introduced into a flow of carrier gas, the temperature of which is 40-50% lower than the melting temperature of the original radio-absorbing powder material. The heterogeneous flow is accelerated to supersonic speed and directed towards the substrate. The particles are decelerated against the substrate surface at a temperature and speed lower than that required to form the coating, resulting in flattening and the production of deformed particles.EFFECT: increase in magnetic permeability and a decrease in the dielectric constant of particles of radio-absorbing powders.1 cl, 1 dwg

Description

[0001] The invention relates to the technology of gas-dynamic application of coatings from powder materials and can be used in mechanical engineering, aerospace engineering, the automotive industry, energy, construction, the oil and gas industry and other areas of the economy.

[0002] The “Method for applying coatings” is known (RU Patent No. 2306368, IPC C23C 23 / 03, published: 09.20.2007, Bulletin No. 26).

[0003] A method for applying a coating to cast iron parts, which includes treating the part with an abrasive powder material with a particle size of 30-300 μm, heating compressed air, feeding it into a supersonic nozzle, forming a supersonic air flow in the nozzle, feeding a powder material intended for forming a coating into the flow and directing it to the surface of the workpiece, wherein before treating the part with an abrasive powder material, a flux with an activity time of 0.2-0.25 h is applied to the surface of the part, containing up to 30% ammonium chloride NH4Cl, up to 70% zinc chloride ZnCl2 and up to 2% potassium permanganate KMnO4, and heating the surface over the flux with a burner with an oxidizing flame to a temperature of (0.14-0.2) Tpl, where Tpl is the melting point of cast iron.

[0004] The disadvantage of this method is the impossibility of obtaining particles of radio-absorbing powders with high magnetic permeability.

[0005] The prototype of the claimed method is the “Method for applying coatings” (Application for invention No. 95110652 dated 06 / 28 / 1995, IPC C23C 4 / 00).

[0006] A method for applying coatings, including introducing a powder of a sprayed material into a formed gas flow, accelerating the formed two-phase flow in a gas-dynamic nozzle and depositing particles from the accelerated flow onto the surface being treated at a particle temperature in the flow lower than the melting temperature of the sprayed material, during the deposition of particles, the possibility of a shock wave occurring in the accelerated two-phase flow is prevented.

[0007] In this case, the occurrence of a shock wave in a two-phase flow is prevented by selecting the particle size, their concentration in the gas flow, the gas or gas mixture used in such a way that the speed of the gas flow between the nozzle exit and the surface being processed is less than the speed of sound in the two-phase flow.

[0008] In this case, when accelerating a two-phase flow to a supersonic speed, the occurrence of a shock wave in the flow is prevented by its preliminary shock-free braking between the nozzle exit and the surface being processed to a speed less than or equal to the speed of sound in the two-phase flow.

[0009] In this case, shock-free braking of the two-phase flow is carried out by selecting the distance between the nozzle cut and the surface being processed.

[0010] In this case, a powder consisting of particles ranging in size from 1 to 200 microns is used.

[0011] In this case, copper is used as the sprayed material.

[0012] In this case, the relative mass content of copper particles in the gas flow is maintained at no more than 0.2.

[0013] In this case, helium with a temperature of 300 K is used as gas, while the speed of the gas flow at the outlet of the nozzle is maintained at no more than 800 m / s.

[0014] In this case, air with a temperature of 700 K is used as the gas, while the speed of the gas flow at the outlet of the nozzle is maintained at no more than 440 m / s.

[0015] In this case, the workpiece is moved relative to the accelerated flow.

[0016] A method for applying coatings, which includes introducing powder of the material to be sprayed into a formed gas flow, accelerating the formed two-phase flow in a gas-dynamic nozzle and depositing particles from the accelerated flow onto a surface to be treated at a temperature of the particles in the flow lower than the melting temperature of the material to be sprayed, characterized in that the two-phase flow is accelerated until a supersonic speed is achieved, at which the magnitude of the velocity of the particles of the material to be sprayed behind the front of the shock wave arising between the nozzle exit and the surface to be treated does not exceed the magnitude of the velocity of the gas flow in the corresponding region of the two-phase flow.

[0017] In addition, shock-free braking of the two-phase flow between the nozzle exit and the surface being processed is carried out.

[0018] In this case, shock-free braking of the two-phase flow is carried out by selecting the distance between the nozzle cut and the surface being processed.

[0019] In this case, a powder consisting of particles ranging in size from 1 to 200 microns is used.

[0020] In this case, copper is used as the sprayed material.

[0021] In this case, the relative mass content of copper particles in the gas flow is maintained at no more than 0.2.

[0022] In this case, air with a temperature of 700 K is used as the gas, while the speed of the gas flow at the outlet of the nozzle is maintained at no more than 600 m / s.

[0023] In this case, helium with a temperature of 300 K is used as gas, while the speed of the gas flow at the outlet of the nozzle is maintained at no more than 1050 m / s.

[0024] In this case, the workpiece is moved relative to the accelerated flow.

[0025] The disadvantage of this method is the impossibility of obtaining particles of radio-absorbing powders with high magnetic permeability.

[0026] The objective of the invention is to create a method for producing particles of radio-absorbing powders.

[0027] The technical result is an increase in magnetic permeability and a decrease in the dielectric constant of particles of radio-absorbing powders.

[0028] The technical result is achieved in that in the method for producing particles of radio-absorbing powders, which consists in the fact that particles of radio-absorbing powder are introduced into a gas flow, as a result of which the heterogeneous flow, accelerated and exiting the nozzle apparatus, is slowed down against the substrate, while the temperature of the carrier gas and the speed are determined so that deformation of the particles of radio-absorbing powders occurs, while the particles hit a special surface at their temperature and speed less than that necessary for the formation of the coating, as a result of which the necessary deformation of the particles of radio-absorbing powders occurs.

[0029] Fig. 1 shows a block diagram of the installation for producing particles of radar-absorbing powders. The following designations are used in the block diagram: 1 - compressed air cylinder; 2 - carrier gas heater; 3 - carrier gas parameter and mass flow control system; 4 - powder dispenser; 5 - mixing chamber with accelerator; 6 - heterogeneous supersonic flow; 7 - impact surface.

[0030] Carrier gas from a compressed air cylinder (1) is fed through a heater (4) into a mixing chamber and accelerator (5), where it is accelerated to the required speed. Another portion of the carrier gas, regulated by the control system (3), feeds powder through a dispenser (4) into the mixing chamber and accelerator (5), from which a heterogeneous stream (6) emerges, striking the surface (7).

[0031] The initial temperature of the carrier gas is 40-50% lower than the melting point of the starting powder. Additional energy is imparted to the particle in a special accelerator (5) to accelerate the heterogeneous mixture (gas + powder) to the required supersonic speed. When high-speed particles collide with a solid surface, the dissipation of their kinetic energy results in flattening and the particles fail to fuse due to insufficient carrier gas temperature.

Claims

A method for producing deformed particles of a radio-absorbing powder, which includes introducing the original radio-absorbing powder into a carrier gas flow to produce a heterogeneous flow, accelerating the heterogeneous flow and braking it against a substrate, characterized in that the particles of the original radio-absorbing powder are introduced into a carrier gas flow, the temperature of which is 40-50% less than the melting temperature of the material of the original radio-absorbing powder, the acceleration of the heterogeneous flow is carried out to supersonic speed, and the braking of the particles against the surface of the substrate occurs at a temperature and speed lower than that necessary for the formation of a coating, ensuring flattening and the production of deformed particles.

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