Method for preparing composite material by vibration-assisted cold spraying of multi-path powder feeding spray gun

Abstract

The invention relates to a method for preparing a composite material by vibration-assisted cold spraying of a multi-path powder feeding spray gun, which comprises the following steps: mounting a vibrator on the upstream of the outer wall of the spray gun, preparing a plurality of powder feeders according to the components of the target composite material, and enabling one powder feeder to correspond to one component; the high-pressure gas source is divided into a powder feeding branch and a spraying branch, gas in the powder feeding branch feeds different types of powder materials into the corresponding powder feeders respectively, and then the powder materials are fed into the premixing chamber through the powder feeders; gas of the spraying branch is preheated by a heater and then enters a premixing chamber to mix and heat powder materials in the premixing chamber; and the powder material in the premixing chamber is fed into the spray gun, the vibrator is started to work, the spray gun moves and sprays the base body, and powder particles collide with the base body to form a composite coating or a block material. The device can greatly improve the uniformity of a composite material coating or block, is economical and practical, is simple to operate, can realize whole-process automation, and is wide in application range.

Description

Technical Field

[0001] The invention belongs to the technical field of material surface engineering and additive manufacturing. Background Art

[0002] With the continuous breakthrough of technology and the development of high-tech industries, the increasingly harsh working conditions make it difficult for single-structure materials to meet the use requirements. Composite materials are composed of two or more materials. Through their combination, they can combine the advantages of each material to make up for the disadvantages, thereby achieving the purpose of optimizing the overall performance of the material.

[0003] At present, the traditional methods for preparing composite materials include powder metallurgy, electromagnetic stirring, laser melting additive manufacturing and thermal spraying. However, the above methods have the characteristics of high temperature, which can easily cause adverse effects such as oxidation, element burning and segregation. Cold spraying is a new solid-state forming technology based on aerodynamics. Micron-sized powder particles are carried by high-pressure airflow and accelerated by Laval nozzles, and then hit the substrate at a very high speed. The metal particles undergo strong plastic deformation. When the particle speed exceeds the critical value, they can be effectively deposited on the substrate surface to form a coating or deposited body.

[0004] Since the temperature of cold spraying is always lower than the melting point of the powder, a series of problems such as pores, segregation, phase change, etc. caused by the melting-solidification process can be avoided. In recent years, cold spraying has also shown great advantages in the field of preparing composite materials. Powders of different proportions and different compositions are simply mechanically mixed and fed into the powder feeder, and a composite coating or deposited body can be obtained after cold spraying. However, when preparing composite materials with different compositions, it is necessary to redesign and mix new powders, and it is necessary to clean the old powder in the previous powder feeder before putting in the new powder, and then start cold spraying. This process is relatively complicated and reduces work efficiency.

[0005] The use of dual (multiple) powder feeders can avoid this procedure, and can also achieve online control of composite materials with different proportions, which is also conducive to the preparation of gradient composite materials. However, when using dual (multiple) powder feeders, when the speed of the non-main phase powder feeder is low, the prepared composite material has the problem of unevenness, which has an adverse effect on the use of structural parts in harsh environments.

[0006] Therefore, how to obtain composite materials with more uniform composition through regulation to meet the use requirements of structural parts is an urgent problem to be solved. Summary of the invention

[0007] The purpose of the present invention is to avoid the shortcomings of the prior art and provide a method for preparing composite materials by vibration-assisted cold spraying of a multi-channel powder feeding spray gun, which can obtain composite materials with more uniform composition in the simplest way at the lowest cost.

[0008] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing composite materials by vibration-assisted cold spraying of a multi-channel powder feeding spray gun, comprising the following steps:

[0009] The high-pressure gas source is divided into a powder delivery branch and a spraying branch;

[0010] Different types of powder materials are sent into the corresponding powder feeder through the high-pressure air source of the powder feeding branch, and then sent into the premixing chamber by the powder feeder; at the same time, the high-pressure air source of the spraying branch also enters the premixing chamber after being preheated by the heater; different types of powder materials are mixed and heated in the premixing chamber, and then the powder materials are sent into the spray gun;

[0011] Among them, multiple powder feeders are equipped according to the components of the target composite material, and each powder feeder corresponds to one powder material;

[0012] Before the powder material is fed into the spray gun, a vibrator installed upstream of the spray gun and nested with the outer wall of the spray gun is started, and then powder is fed to the spray gun. The vibrator causes the spray gun to vibrate in situ in a plane perpendicular to the axis of the spray gun, so that the powder is evenly mixed and then sprayed on the substrate. The particles of the powder material collide with the substrate to form a composite coating or a block material;

[0013] The vibrator has a working amplitude of 100 to 500 μm and a vibration frequency of 1000 to 5000 Hz, which is used to prevent the powder from hitting the inner wall of the spray gun and causing blockage due to excessive amplitude during the entire powder feeding and spraying process of the spray gun.

[0014] Furthermore, the vibrator is sleeved on the outer wall of the spray gun and fixedly connected to the outer wall of the spray gun by screws, and the vibrator is an electromagnetic vibrator or a pneumatic vibrator.

[0015] Furthermore, the rotation speed of the powder feeder is 0.1-5 rpm.

[0016] Furthermore, the powder material is metal-metal or metal-non-metal; the metal is Al, Cu, Ti, Mg, Fe, Ni and their alloys, and the non-metal is SiC, TiN, Al2O3, or WC ceramics.

[0017] Furthermore, the powder material has a particle size of 5 to 100 μm and a spherical or irregular shape.

[0018] Furthermore, the high-pressure gas source is compressed air, nitrogen, helium, argon or a mixture thereof.

[0019] Furthermore, the pressure of the high-pressure gas source is 1.0-5.0 MPa; the gas pressure of the powder delivery branch is 0.01-0.1 MPa higher than the gas pressure of the spraying branch.

[0020] Furthermore, the preheating temperature of the heater is lower than the melting point of the powder material.

[0021] Furthermore, the shape of the interior of the spray gun in the spraying direction is a cone or trumpet-shaped spray gun that first contracts and then expands, and the vibrator is completely installed upstream of the spray gun, and the upstream length of the spray gun is not shorter than 1 / 3 of the downstream length.

[0022] Furthermore, the shape of the interior of the spray gun in the spraying direction is a cone or trumpet-shaped spray gun that first contracts and then expands, and the vibrator is installed upstream of the spray gun in the contraction section with the largest cross-sectional area, and the upstream length of the spray gun is not shorter than 1 / 3 of the downstream length.

[0023] The beneficial effects of the present invention are as follows: by using multiple powder feeders to feed heterogeneous powders, a vibrator with simple harmonic motion characteristics is arranged on the outer wall of the spray gun, which is conducive to the common deposition of heterogeneous powder particles, and can greatly improve the uniformity of composite material coatings or blocks, thereby improving the mechanical properties of cold-sprayed composite material structures, solving the problem of uneven composition of cold-sprayed composite materials, being economical and practical, simple to operate, fully automated, and having a wide range of applications, providing a new method for the efficient repair of composite material parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is the working principle diagram of the present invention;

[0025] Figure 2 This is a schematic diagram of the assembly structure of the vibrator and the spray gun of the present invention;

[0026] Figure 3 A schematic cross-sectional structure diagram of the assembly of the vibrator and the spray gun of the present invention;

[0027] Figure 4 Another cross-sectional structural schematic diagram of the assembly of the vibrator and the spray gun of the present invention;

[0028] Figure 5 This is the cross-sectional electron microscopic structure of the Al-SiC composite coating prepared in Example 1 of the present invention;

[0029] Figure 6 This is the cross-sectional electron microscope structure of the Al-SiC composite coating prepared in Control Example 1 of the present invention.

[0030] In the figure: 1-spray gun, 2-vibrator, 3-screw. DETAILED DESCRIPTION

[0031] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0032] In order to achieve the above object, the present invention provides the following specific implementation methods:

[0033] Example 1: Figure 1 , Figure 2 , Figure 3 As shown, a method for preparing composite materials by vibration-assisted cold spraying of a multi-channel powder feeding spray gun comprises the following steps:

[0034] like Figure 1 As shown, the high-pressure gas source is divided into a powder delivery branch and a spraying branch;

[0035] Different types of powder materials are fed into the corresponding powder feeder through the high-pressure air source of the powder feeding branch, and then fed into the premixing chamber by the powder feeder; at the same time, the high-pressure air source of the spraying branch also enters the premixing chamber after being preheated by the heater, and the preheating temperature of the heater is lower than the melting point of the powder material; different types of powder materials are mixed and heated in the premixing chamber, and then the powder materials are fed into the spray gun;

[0036] Wherein, a plurality of powder feeders are provided according to the components of the target composite material, and each powder feeder corresponds to a powder material; the rotation speed of the powder feeder is 0.1 to 5 rpm;

[0037] The powder material is metal-metal or metal-nonmetal; the metal is Al, Cu, Ti, Mg, Fe, Ni and their alloys, the nonmetal is SiC, TiN, Al2O3, WC ceramics, the particle size of the powder material is 5 to 100 μm, and the shape is spherical or irregular.

[0038] The high-pressure gas source is compressed air, nitrogen, helium, argon or a mixture thereof. The pressure of the high-pressure gas source is 1.0-5.0 MPa; the gas pressure of the powder feeding branch is 0.01-0.1 MPa higher than the gas pressure of the spraying branch.

[0039] Before the powder material is fed into the spray gun, a vibrator installed upstream of the spray gun and nested with the outer wall of the spray gun is started, and then powder is fed to the spray gun. The vibrator causes the spray gun to vibrate in situ in a plane perpendicular to the axis of the spray gun, so that the powder is evenly mixed and then sprayed on the substrate. The particles of the powder material collide with the substrate to form a composite coating or a block material;

[0040] The vibrator has a working amplitude of 100 to 500 μm and a vibration frequency of 1000 to 5000 Hz, which is used to prevent the powder from hitting the inner wall of the spray gun and causing blockage due to excessive amplitude during the entire powder feeding and spraying process of the spray gun.

[0041] like Figure 2 and Figure 3As shown, the vibrator 2 is sleeved on the outer wall of the spray gun 1 and fixedly connected to the outer wall of the spray gun 1 by screws 3. The vibrator 2 is an electromagnetic vibrator or a pneumatic vibrator. The shape of the inside of the spray gun 1 in the spraying direction is a cone or trumpet-shaped spray gun that contracts first and then expands. The vibrator 2 is completely covered on the upstream of the spray gun, and the upstream length of the spray gun is not shorter than 1 / 3 of the downstream length.

[0042] Example 2: Figure 1 , Figure 2 , Figure 3 As shown, it is the same as Example 1, except that: the shape of the interior of the spray gun 1 in the spraying direction is a conical or trumpet-shaped spray gun that first contracts and then expands, and the vibrator 2 is coated on the upstream of the spray gun in the contraction section with the largest cross-sectional area, and the upstream length of the spray gun is not shorter than 1 / 3 of the downstream length.

[0043] In order to further illustrate the technical effects of the present invention, Figure 5 , Figure 6 As shown, the present invention also provides the following specific operation examples and comparative examples:

[0044] Specific operation examples:

[0045] Step 1: Use eight screws 3 to firmly assemble the vibrator 2 and the outer wall of the spray gun 1 upstream.

[0046] Step 2: There are two components of the target composite material: spherical Al powder and SiC powder with a particle size of 15-45 μm; equipped with two powder feeders.

[0047] Step 3: Use nitrogen as the high-pressure gas source to enter the powder feeding branch and the spraying branch respectively. The gas pressure of the powder feeding branch is 3.05MPa; the gas pressure of the spraying branch is 3MPa; the gas in the powder feeding branch sends spherical Al powder into powder feeder No. 1 and SiC powder into powder feeder No. 2. Subsequently, powder feeder No. 1 sends Al powder into the premixing chamber at a speed of 5rpm, and powder feeder No. 2 sends SiC powder into the premixing chamber at a speed of 1rpm. The gas in the spraying branch is preheated by the heater and then enters the premixing chamber to mix and heat the powder materials therein, and then the powder materials are sent to the spray gun; the temperature of the heater is 500℃.

[0048] Step 4: Start the vibrator 2 to start working. The amplitude of the vibrator 2 is set to 500μm and the frequency is 1000Hz. The spray gun 1 moves at a rate of 250mm / s while vibrating in a plane perpendicular to the axis of the spray gun and sprays the substrate. The powder particles collide with the substrate to form a composite coating. Figure 5 , it can be seen that Al and SiC are evenly distributed in the cross section of the composite material.

[0049] Comparative Example 1:

[0050] The preparation method is the same as the specific operation example, except that the vibrator 2 is not started. The prepared composite coating has a cross-sectional structure under a scanning electron microscope. Figure 6 , it can be seen that the Al and SiC distribution in the composite material cross section is uneven.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing composite materials by vibration-assisted cold spraying of a multi-channel powder feeding spray gun, characterized in that: The steps include: The high-pressure gas source is divided into a powder delivery branch and a spraying branch; Different types of powder materials are fed into the corresponding powder feeder through the high-pressure air source of the powder feeding branch, and then fed into the premixing chamber by the powder feeder; at the same time, the high-pressure air source of the spraying branch also enters the premixing chamber after being preheated by the heater; Different types of powder materials are mixed and heated in the premixing chamber, and then the powder materials are fed into the spray gun; Among them, multiple powder feeders are equipped according to the components of the target composite material, and each powder feeder corresponds to one powder material; Before the powder material is fed into the spray gun, a vibrator installed upstream of the spray gun and nested with the outer wall of the spray gun is started, and then powder is fed to the spray gun. The vibrator causes the spray gun to vibrate in situ in a plane perpendicular to the axis of the spray gun, so that the powder is evenly mixed and then sprayed on the substrate. The powder particles collide with the substrate to form a composite coating or block material; The vibrator has a working amplitude of 100 to 500 μm and a vibration frequency of 1000 to 5000 Hz, which is used to prevent the powder from hitting the inner wall of the spray gun and causing blockage due to excessive amplitude during the entire powder feeding and spraying process of the spray gun.

2. The method for preparing composite materials by vibration-assisted cold spraying of a multi-channel powder feeding spray gun according to claim 1, characterized in that: The vibrator is sleeved on the outer wall of the spray gun and fixedly connected to the outer wall of the spray gun through screws. The vibrator is an electromagnetic vibrator or a pneumatic vibrator.

3. The method for preparing composite materials by vibration-assisted cold spraying of a multi-channel powder feeding spray gun according to claim 1, characterized in that: The rotation speed of the powder feeder is 0.1-5 rpm.

4. The method for preparing composite materials by vibration-assisted cold spraying of a multi-channel powder feeding spray gun according to claim 1, characterized in that: The powder material is metal-metal or metal-non-metal; the metal is Al, Cu, Ti, Mg, Fe, Ni and alloys thereof, and the non-metal is SiC, TiN, Al2O3, or WC ceramics.

5. The method for preparing composite materials by vibration-assisted cold spraying of a multi-channel powder feeding spray gun according to claim 1, characterized in that: The particle size of the powder material is 5 to 100 μm, and the shape is spherical or irregular.

6. The method for preparing composite materials by vibration-assisted cold spraying of a multi-channel powder feeding spray gun according to claim 1, characterized in that: The high-pressure gas source is compressed air, nitrogen, helium, argon or a mixture thereof.

7. The method for preparing composite materials by vibration-assisted cold spraying of a multi-channel powder feeding spray gun according to claim 1, characterized in that: The pressure of the high-pressure gas source is 1.0-5.0 MPa; the gas pressure of the powder delivery branch is 0.01-0.1 MPa higher than the gas pressure of the spraying branch.

8. The method for preparing composite materials by vibration-assisted cold spraying of a multi-channel powder feeding spray gun as claimed in claim 1, characterized in that: The preheating temperature of the heater is lower than the melting point of the powder material.

9. The method for preparing composite materials by vibration-assisted cold spraying of a multi-channel powder feeding spray gun according to any one of claims 1 to 8, characterized in that: The shape of the interior of the spray gun in the spraying direction is a cone or trumpet-shaped spray gun that first contracts and then expands. The vibrator is completely installed upstream of the spray gun, and the upstream length of the spray gun is not shorter than 1 / 3 of the downstream length.

10. The method for preparing composite materials by vibration-assisted cold spraying of a multi-channel powder feeding spray gun according to any one of claims 1 to 8, characterized in that: The interior of the spray gun is shaped like a cone or trumpet in the spraying direction, which contracts first and then expands. The vibrator is installed upstream of the spray gun at the contraction section with the largest cross-sectional area, and the upstream length of the spray gun is not shorter than 1 / 3 of the downstream length.

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