A method of obtaining a coating of powder materials and device for its implementation

 

(57) Abstract:

The invention can be used in metallurgical, machine-building, electronic industries. The method includes forming the accelerating flow of carrier gas, the introduction of particles of the powder material, the supply of gas-powder mixture obtained in accelerating supersonic nozzle and applying the powder material on the surface of the product. Before the introduction of the powder into the flow of the working gas, it was subjected to preliminary acceleration inert with respect to the source of powder material gas to a velocity determined by the number 0,M,0, gas-powder mixture in accelerating supersonic nozzle is introduced into the core of accelerating the flow of the working gas, and before applying the powder material on the surface of the conducting Department of the powder particles from the gas. The device comprises a spray site, made in the form of accelerating supersonic nozzle subsonic narrowing and expanding supersonic parts and the intermediate nozzle, means for supplying compressed working gas carrier, means entering the gas-powder mixture in the spray site and the feeder-hopper, means for supplying additional pressurized inert in respect to the about with the possibility of axial translational movement in its subsonic part, and accelerating supersonic nozzle is out of the supersonic part of the linear region followed by a section with a curved surface of radius R. the Method allows to extend the technological capabilities to produce coatings of different powder materials, to increase the efficiency of the application process. 2 C. and 15 C.p. f-crystals, 2 Il.

The invention relates to the field of application and coatings from powder materials and can be used in metallurgical, machine-building, electronic and other industries to improve the technological and physico-chemical properties of the products, recovery of various worn parts and make the surface of product specific properties.

A method of obtaining coatings of powder materials, including the introduction of the source of powder material in the accelerating particle material gas flow, the formation of a high-speed gas-powder jet and the application of the powder material on the surface [1].

The disadvantages of this method are: the inability to disperse the gas stream, the particles of the coating material to speeds close to the speed of the accelerating their gas, and implement 10105h/m2.

These drawbacks limit the technological capabilities of the method and require substantial resources.

Also known is a method of obtaining coatings of powder materials on the surface of the product, the material of which is selected from the group consisting of metals, alloys or dielectrics, including the formation of accelerating the flow of carrier gas, the introduction of particles of the powder material, the supply of gas-powder mixture obtained in accelerating supersonic nozzle and applying the powder material on the surface of the product gas stream [2].

To implement this method, you use the device containing the spray site, made in the form of a supersonic nozzle with subsonic tapering and supersonic parts and the intermediate nozzle, means for supplying compressed working gas of the carrier and the means of entering gas-powder mixture in the spray site [2].

The disadvantages of the known method and device is the limited access to quality of the coating material due to the presence of the particles used powder materials of the surface oxide film and, as a result, the presence of oxides in the structure the atom parietal layer of gas near the surface of the workpiece, not high enough physico-chemical properties of the obtained coatings limited speed control the gas flow and particles of the powder material from which the coating is formed, the presence of friction and deceleration of particles along the walls of the accelerating tract supersonic nozzle, resulting in reduced efficiency of the coating process and resource spray system. The known device is rather complicated in construction execution. These shortcomings do not allow to obtain coatings with excellent physical and mechanical properties, narrow technological capabilities of producing high-quality coverage of powder materials and do not provide the high efficiency of the coating process and high resource spray system.

The basis of the described invention is the task of creating a method of producing coatings of powder materials and devices for its implementation, which would expand the technological capabilities to produce coatings of different powder materials and their mechanical mixtures, to improve the physicochemical properties of the obtained coating material, to increase the efficiency of the process caused the t is achieved through the use of the method of producing a coating of powder materials and devices for its implementation, the essence of which consists in the following.

In the process for coating of powder materials, including the formation of accelerating the flow of carrier gas, the introduction of particles of the powder material, the supply of gas-powder mixture obtained in accelerating supersonic nozzle and applying the powder material on the surface of the product gas stream, is provided before the filing of the gas-powder mixture in the upper nozzle pre-acceleration inert with respect to the source of powder material gas to a velocity determined by the number of 0.3 M and 1.0, where M is the Mach number, and additional acceleration by entering a gas-powder mixture in the core of accelerating the flow of carrier gas, and before application of the powder coating material on the surface of the product provides for the separation of powder particles from the gas.

The formation of the accelerating flow of carrier gas is performed in the square-law changes to the profile of the square of the accelerating supersonic nozzle. This allows for more efficient use of energy gas stream.

It is advisable to supply gas-powder mixture in the upper nozzle when the amount is poured in accordance with the calculated mode of the accelerating nozzle.

The method involves the use as a working carrier gas of air or mixture of gases, and as inert with respect to the powder material gas charge gas or mixture of gases, which are not entering into a chemical reaction with the powder components of this material.

Prior to acceleration of the powder material is subjected to mechanical, electrochemical or chemical treatment in inert to the source of powder material gas environment and in the flow of this medium served in the feeder-hopper.

Preferably in an inert relative to the powder material gas use gas with temperature T 300 K.

Supply of gas-powder mixture in the core of accelerating the flow from the feeder-dispenser can be carried out in a pulsed mode.

When applying the powder material on the surface of the latter may undergo oscillatory movement coaxially of the rolling two-phase supersonic flow.

To increase the plasticity of the substrate product is subjected to surface heating.

In the coating process for the covered product may be submitted potential, opposite seropositive device is the device for producing coatings from powder materials containing the spray site, made in the form of accelerating supersonic nozzle subsonic tapering and supersonic parts and the intermediate nozzle, means for supplying compressed working gas carrier, means entering the gas-powder mixture in the spray site and the feeder-hopper, provided with a means for supplying additional pressurized inert with respect to the powder material gas, an intermediate nozzle made supersonic diameter of cut dcfless than the diameter of the critical section Dkrthe accelerating nozzle and coaxially installed with the possibility of translational movement in its subsonic tapering part and accelerating supersonic nozzle is out of the supersonic part of the linear region followed by a section with a curved surface of radius R

The device has a node for processing the powder material to activate and clean the surface of the particles of the coating material, the pulsator gas, connected with the input tool gas-powder mixture, vibrator for a message fluctuations of the coated product and a power source for supplying potential to the product.

The device comprises a means 1 compressed inert to the coating material (powder mixture components) gas shut-off valve 2, node 3 pre-treatment of the powder material to remove the oxide film and the activation of the particles, the node 4 collection oxide film and the fine fraction of the powder, the node 5 feed treated powder material in the feeder-hopper 6, the shutoff valve 7, the pulsator 8 is inert with respect to the powder material gas, the tool 9 supply of operating a carrier gas (e.g. air), the system 10 workflow control coating the heater 11 of the working gas carrier, the node 12 translational axial movement of the intermediate supersonic nozzle 13, a camera 14, the alignment of the flow of carrier gas, the centering profile sleeve 15, accelerating supersonic nozzle 16 with a linear plot 17, passing in the area with a curved surface 18 for changing the direction of movement of the gas stream, means 19 of the exhaust gas flow from the covered unit 20, the tool 21 mounting and rotating the source 24 power the outlet 25 of the feed gas-powder mixture outlet 26 of the gas feed carrier.

Implementation of the described method and device is as follows.

Inert to the coating material (powder mixture components) gas pressure from 1 filing with the open shut-off valve 7 is supplied to the node 3 pre-treatment of the powder coating material, pre-filled with the required amount of powder (mixture of powders). When the node 3 pre-treatment of the powder material in it mechanical or other means removes the oxide film from the surface of the particles of the powder coating material. Waste pre-treatment in the form of particles of the oxide film and uncalibrated fine fraction of the powder received in the node 4. This is followed by activation of the particles of the powder coating material of the electromagnetic, thermal, chemical or other means, depending on the chemical composition and physical properties of the powder material (a mixture of powdered components) coverage. Activated particles through node 5 supply of powder material are supplied to the feeder-hopper 6. After filling po close the shutoff valve 2, stopping the supply of inert with respect to the powder material gas.

To obtain coatings of powder materials work carrier gas (e.g. air, nitrogen) under pressure from the means 9 of the feed is fed into the system 10 workflow control coating, where the pressure is reduced to the desired operating values. Reduced to the desired pressure gas enters the heater 11 of the gas, where it is heated to a temperature corresponding to the calculated mode of operation. The heated working gas medium flows through the pipe 26 to the supply of operating a carrier gas into the chamber 14 of the alignment of the flow of carrier gas and then through a shaped hole in the centering sleeve 15 enters the accelerating supersonic nozzle 16, where can accelerate to its desired application and formation of the coating speed. When reaching the required parameters of the working gas carrier open shut-off valve 7, through the supply of inert with respect to the powder material gas, which first enters the pulsator 8, which takes the appropriate frequency pulsation component. From the pulsator 8 is inert with respect to the powder material gas with the required frequency enters the PI forms a gas-powder mixture, in which powder particles are in the form of mist. The obtained gas-powder mixture in the form of two-phase flow is fed through the pipe 25 into the intermediate supersonic nozzle 13 and then in the core of accelerating the flow of carrier gas into the region of the critical section of the accelerating supersonic nozzle 16. To achieve the required calculation of thermodynamic parameters for the operation of carrier gas and a pulsating gas-powder mixture in the area of critical sections accelerating supersonic nozzle 16 is moved intermediate supersonic nozzle 13. This movement is carried out progressively along the axis of the nozzle through node 12 axial movement by an amount dependent on the velocity of the expiration and frequency of the pulsations of the gas-powder mixture in the critical region of the upper section of a supersonic nozzle 16. After reaching the desired value of the displacement produced off site 12 axial movement of the intermediate supersonic nozzle 13. Flowing from the intermediate supersonic nozzle 13 pulsing the mixture of particles with inert for them gas having an initial axial velocity of 0.3 M to 1.0 (where M is the Mach number), mixed in the area of critical sections accelerating supersonic nozzle 16 with a work carrier gas, where PR is the necessary speed, the flow of the gas-powder mixture aligns the direction of its motion at a linear section 17 and then the main part of the gas flow turns in the plot, having a curved surface 18, getting into the inlet pipe means 19 of the exhaust gas stream. Powder particles of the coating material, having greater mass and inertia, continue straight motion before the collision with the surface of the coated product. Upon reaching the desired thermal and gas-dynamic modes for coating the lead in the movement (reciprocating, rotary) covered product 20, mounted in the tool 21 of fastening products. Then turn the vibrator 23 is connected to the node 22 travel products, and a power source 24, the feed opposite to the moving particle potential on the workpiece 20. Thus, the process of application and formation of the coating on the surface of the product.

As a gas, inert with respect to the powder material can be selected gas (mixture of gases), which are not entering into a chemical reaction with the powder coating material, such as nitrogen, argon, helium, krypton, etc. the Choice of gas is determined by the specific requirements to the properties of the obtained proszkowych particles of the coating material, their activation, transportation and pre-acceleration inert for them gas prevents oxidation of the coating material and allow for application and formation of the coating to obtain chemically pure, without oxides in their structure materials, to improve their structure, physical-chemical and technological properties.

Utilization of coating material coating, adhesion, cohesion and its structure depend on the speed of the collision damage of the coating particles on the surface of the material. Preliminary acceleration of the particles of the coating material inert to them gas at temperature T 300 K, the speed of the accelerating their gas 0.3 M to 1.0 and commissioning of gas-powder mixture in the engine accelerating their carrier gas can significantly increase the speed of particles of the coating material to a speed close to the speed of the accelerating their gas, thereby maximizing use of energy accelerating their gas jet. Enter gas-powder mixture in the core of accelerating the flow of carrier gas removes the braking effect of the particles on the walls of the flow part accelerating supersonic nozzle, increases the resource use device, the utilization ratio of the applied coating material. To resolve effecf gas on the surface of the product, in the described method produces a rotation of the gas stream and its removal from the surface of workpiece.

Turn the gas flow due to the physical effect that occurs when the flow plane-parallel gas flow curved surface of radius R. Thus, the rotation of the gas stream and its removal from the surface of workpiece eliminates the appearance of parietal compressed gas layer on the surface of the product and the particles of the coating, continuing its rectilinear movement, reach the surface of the product with the speed they gained while interacting with accelerating their gas flow. This allows for less energy parameters of the gas stream to cause the particles of the coating material with a higher speed collision with the surface of the material, resulting in lower energy consumption, increase the utilization of the coating material, to improve the structure, quality and properties of the coating material.

The establishment of the total consumption of the accelerating flow of carrier gas and inert with respect to the powder coating material gas in accordance with the calculated mode of the expiration of the accelerating nozzle is because calc is correspond to ambient pressure. Under this condition, the flow rate of the gas flow from the supersonic nozzle is maximum. Any change in the parameters of a carrier gas, such as temperature, pressure, race gas, result in off-design mode expires, i.e., the loss of gas flow speed and hence the speed of the particles of coating material coating.

Oscillatory movement of the workpiece when the synchronous input pulsed gas-powder mixture in the engine accelerating their flow of carrier gas is conducted in such a way that the supply of gas-powder mixture is carried out at the time when the movement of workpiece occurs towards the flow of particles of coating material coating. In this case, is the sum of the velocities of moving particles of the coating material and the speed of movement of workpiece. As a result, the speed of collision of particles with the surface increases. This increases the depth of penetration of the particles into the surface of the material, the degree of plastic deformation, increase the utilization rate of the coating material, to improve the structure of the coating and its technological properties.

To intensify the flow IU is offset from the surface of the product in the described method produces a surface heated product to a temperature in which the plasticity of the surface material close to the plasticity of the coating material. This allows you to apply a coating having a lower hardness on a more solid and less plastic surface. In this case dramatically change the properties of the transition zone (material particles and the material of the product), improves its structure and, consequently, the adhesion of the coating. In the transition zone also forms the intermetallic compound in the coating metal on metal, consisting of a material damage of the coating particles and the material of the product. Solid particles during its movement in the gas stream become defined by the size and sign of the charge due to the friction of the gas, each other and against the walls of the flow of the gas path. The magnitude and sign of the charge depends on the material particles. When applying the inverse of the sign of the potential in the described manner on the surface of the coated product is to increase the speed of the charged particles when approaching the surface of the product and the occurrence of microarc discharge at impact.

Acting on a moving stream of charged particles of various electromagnetic methods and the amount of supplied potential product, it is possible to manage the process of Napsauta and the quality of the coating. Design features of the input device, gas-powder mixture allow axial input of the coating particles with initial velocity in the core work of accelerating their flow of carrier gas, avoiding the interaction of particles of the coating material with the walls of the accelerating supersonic nozzle 16 under the condition of dcfDkr.

This allows you to increase the resource use device, the maximum use of the energy of the gas stream to increase the kinetic energy of the particles of the coating material, to implement the process of forming a coating with a relatively low input parameters carrier gas, to increase the utilization rate of coating material.

The described invention can be used for multifunctional coatings and materials from various powder components selected from the group comprising metals, alloys, or of mechanical mixture, as well as dielectrics and organic compounds.

By creating conditions that activate and exclude on the surface of particles of the oxide film, the area used for coating materials described by the invention can be significantly enhanced.

1. A method of obtaining a coating of powder materials, including the formation of accelerating the flow of carrier gas, the introduction of particles of the powder material, the supply of gas-powder mixture obtained in accelerating supersonic nozzle and applying the powder material on the surface of the product, characterized in that before the introduction of the powder into the flow of carrier gas it is subjected to preliminary acceleration inert with respect to the source of powder material gas to a velocity determined by the number of

0,3 1,0 M,

where M is the Mach number,

gas-powder mixture in accelerating supersonic nozzle is subjected to additional acceleration by entering it into the kernel uskorea separation of powder particles from the gas.

2. The method according to p. 1, characterized in that the formation of the accelerating flow of carrier gas is performed in the square-law changes square profile accelerating supersonic nozzle.

3. The method according to any of paragraphs.1 and 2, characterized in that the supply of gas-powder mixture in accelerating supersonic nozzle is carried out at a total flow rate of the accelerating flow of carrier gas and inert in relation to the powder material gas, installed in accordance with the calculated mode of the accelerating supersonic nozzle.

4. The method according to any of paragraphs.1 to 3, characterized in that as a working carrier gas using the air and in an inert relative to the powder material gas charge gas or mixture of gases, which are not entering into a chemical reaction with the powder material.

5. The method according to any of paragraphs.1 to 4, characterized in that the pre-acceleration of the powder material is subjected to treatment in an inert towards him gaseous environment to enhance and removing the oxide film from the surface of the powder particles and the flow of this medium served in the feeder-hopper.

6. The method according to p. 5, characterized in that the processing of the powder material by conducting the same time, which is inert with respect to the powder material gas charge temperature T 300K.

8. The method according to any of paragraphs.1 to 7, characterized in that the input gas-powder mixture in the core of accelerating the flow of carrier gas is carried out in a pulsed mode.

9. The method according to any of paragraphs.1 to 8, characterized in that during application of the powder material on the surface of the latter is subjected to oscillatory movement coaxially of the rolling two-phase flow.

10. The method according to any of paragraphs.1 to 10, characterized in that during application of the powder material conducting surface heat products.

11. The method according to any of paragraphs.1 to 10, characterized in that the powder coating material on the coated surface of conduct when serving, the product capacity, opposite the particles flow gas-powder mixture.

12. Device for coating of powder materials containing spray site, made in the form of accelerating supersonic nozzle subsonic narrowing and expanding supersonic parts and the intermediate nozzle, means for supplying compressed working gas carrier, means entering the gas-powder mixture in the spray site and feeder-dotato the material of the coating gas, intermediate nozzle made supersonic diameter of cut dcfless than the diameter of the critical section Dkraccelerating supersonic nozzle and coaxially installed with the possibility of axial translational movement in its subsonic part, and accelerating supersonic nozzle is out of the supersonic part of the linear region followed by a section with a curved surface of radius R

13. The device according to p. 12, characterized in that it is provided with a processing unit of the powder material to activate and clean the surface of the particles, coupled with a means of entering the gas-powder mixture.

14. Device according to any one of paragraphs.12 and 13, characterized in that it is provided with a pulsator connected with a vehicle entering the gas-powder mixture.

15. The device according to p. 14, characterized in that the pulsator installed before the feeder-dispenser.

16. Device according to any one of paragraphs.12 to 15, characterized in that it is equipped with a vibrator for transmitting oscillatory movement of the coated product.

17. Device according to any one of paragraphs.12 to 16, characterized in that it is provided with a power source for supplying potential to the product.

 

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FIELD: portable apparatuses for applying coatings of powder materials by gasodynamic deposition.

SUBSTANCE: apparatus includes compressed gas source, powder meter, deposition unit in the form of portable manual tool with remote control having supersonic nozzle and gas heater rigidly connected with it. Gas heater includes metallic body inside which electric and heat insulation having through mutually parallel pneumatic ducts with inserted in them heating members. Apparatus also includes pneumatic duct for feeding powder from powder meter to supersonic nozzle, locking devices and unit for controlling deposition process, said units are mutually connected through flexible pneumatic ducts and electric connection wires. According to invention electric and heat insulation of gas heater includes inner and outer cylinders coaxially arranged one inside other. Inner cylinder has central through passage for placing pneumatic duct for feeding powder from meter to supersonic nozzle. Pneumatic ducts along its periphery are in the form of grooves. Inner and outer cylinders of electric heat insulation of gas heater are made of heat resistant material having electric and heat insulated coating on surfaces restricting pneumatic ducts.

EFFECT: enlarged manufacturing possibilities, simplified design, lowered mass, improved capability for repairing works, enhanced operational efficiency.

2 cl, 3 dwg

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