Meltallizing process method for increasing surface roughness and application

Abstract

The invention belongs to the technical field of surface processing. The invention provides a meltallizing process method for increasing surface roughness and application. The meltallizing process method comprises the steps that the vertical distance between a meltallizing nozzle and a surface to be treated is controlled to be 20-35 cm, the flow of meltallizing working gas is controlled to be 250-350 L / min, meltallizing is conducted, and a meltallizing layer with the average roughness Ra larger than or equal to 22 micrometers is formed. According to the invention, the vertical distance between the specific nozzle and the surface to be treated, namely the height of the nozzle, is matched with the flow of the specific working gas, so that the average roughness of the surface of the meltallizing layer after meltallizing can be up to more than 28 microns, the value of meltallizing is fully exerted, and the upper limit of the roughness of meltallizing is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of surface processing and relates to a thermal spraying process method for increasing surface roughness and an application thereof. Background Art

[0002] Spraying is an important surface treatment technology. Its basic principle is to heat powder or filament materials to a molten or semi-molten state and spray them onto the substrate surface through a high-speed airflow to form a coating. The sprayed layer (coating) has the advantages of good bonding strength, wear resistance and corrosion resistance, and plays an important role in extending the service life of parts and improving material properties.

[0003] Spraying technology is mainly divided into flame spraying, arc spraying, plasma spraying and other types. Among them, plasma spraying is widely used due to its high operating temperature, good thermal efficiency and ability to melt various high melting point materials. With the development of technology, new spraying technologies such as supersonic spraying (HVOF) and cold spraying are gradually emerging. They can achieve denser and more uniform coating deposition without significantly changing the properties of the base material.

[0004] Due to its unique process characteristics, melt spraying technology has found a wide range of application scenarios in multiple industries. For example, in the aerospace field, in order to improve the high-temperature oxidation and wear resistance of engine blades, melt spraying is often used to prepare protective coatings on their surfaces; in the energy industry, melt spraying technology is used to repair worn parts or enhance the corrosion resistance of parts; and in the biomedical field, melt spraying technology is used to give implants good biocompatibility and bone integration capabilities.

[0005] Surface roughness is an important parameter to measure the microscopic geometric characteristics of the surface of an object, and has a direct impact on the physical and chemical properties of the material. In many cases, appropriate surface roughness can improve the bonding between the coating and the substrate. In certain specific applications, such as manufacturing friction pairs, improving lubrication effects, or enhancing coating adhesion, increasing surface roughness is particularly important. For example, when manufacturing high-performance metal sputtering targets, in order to ensure that the target is not prone to peeling during long-term use, the substrate surface is usually pre-treated through a spraying process to increase its roughness. However, in actual operation, how to accurately control the spraying process to obtain the expected surface roughness is a complex and challenging task.

[0006] Although the spraying technology has shown great potential in increasing surface roughness, the quality of the sprayed coating is affected by many factors, including but not limited to the spraying angle, speed, temperature and the properties of the material itself, which means that it is not easy to achieve highly controllable roughness adjustment. At present, the existing technology for treating the surface of the device using the spraying process can only achieve a surface roughness of less than 22μm. For roughness values ​​≥22μm, there is currently a lack of mature and stable solutions.

[0007] In view of the existence of the above problems, it is particularly urgent to develop a new spraying process that can effectively improve the surface roughness while ensuring the coating quality. Summary of the invention

[0008] In view of the problems existing in the prior art, the purpose of the present invention is to provide a melt spraying process method and application for increasing surface roughness. The melt spraying process method adopts a specific vertical distance between the nozzle and the surface to be treated, that is, the nozzle height, and cooperates with the flow rate of a specific working gas. The average roughness of the surface of the melt sprayed layer after melt spraying Ra ≥ 22μm, and can reach up to 28μm or more.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In the first aspect, the present invention provides a melt spraying process method for increasing surface roughness, the melt spraying process method comprising: controlling the vertical distance between the melt spraying nozzle and the surface to be treated to be 20 to 35 cm, controlling the flow rate of the melt spraying working gas to be 230 to 400 L / min, performing melt spraying, and forming a melt spraying layer with an average roughness Ra ≥ 22 μm.

[0011] The spraying process has unique advantages in adjusting the surface roughness. In the prior art, the morphology of the spraying material sprayed onto the target is too flat and not sharp enough, which makes it difficult to improve the roughness. By controlling the spraying parameters, such as the powder particle size of the molten material, the melting temperature, the working gas injection speed, the injection direction, etc., the microstructure of the coating surface can be adjusted in a wide range, thereby achieving effective regulation of the surface roughness. However, the present invention finds that the change in surface roughness does not show a strict linear relationship with all parameters. Due to the complexity of the spraying parameters, the actual spraying effect after the matching of each parameter is affected, and the change in roughness cannot be easily predicted or accurately controlled. In general, the function of the parameter of the distance between the nozzle and the processing surface is to control the temperature of the spraying material reaching the surface of the material. If the distance is too far, the spraying material has solidified when it reaches the surface, so the spraying material cannot adhere well to the surface to be processed; if the distance is too close, the spraying material is still in a liquid state when it reaches the surface to be processed, which makes it impossible to obtain a sharper spraying surface. The role of the gas flow rate parameter is to control the force of the sprayed material hitting the surface to be treated. If the force is too large, the morphology of the sprayed material will become a "pancake" shape after hitting the surface to be treated, and the roughness will be very low; if the force is too small, the sprayed material cannot be well adhered to the surface to be treated. Of course, the gas flow rate will also affect the cooling rate of the sprayed material, so the above two parameters must complement each other. The present invention unexpectedly discovered that when the vertical distance between the nozzle and the surface to be treated (i.e., the nozzle height) and the flow rate of the working gas are controlled within a certain range, the average surface roughness of the sprayed layer formed after spraying is unexpectedly improved, which can reach more than 22μm, and the spraying effect can reach up to more than 28μm.

[0012] The following are preferred technical solutions of the present invention, but are not intended to be limitations of the technical solutions provided by the present invention. Through the following technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0013] As a preferred technical solution of the present invention, the vertical distance between the nozzle for controlling the spraying and the surface to be treated is 20 to 35 cm, for example, 20 cm, 21 cm, 22 cm, 23 cm, 24 cm, 25 cm, 26 cm, 27 cm, 28 cm, 29 cm, 30 cm, 31 cm, 32 cm, 33 cm, 34 cm or 35 cm, etc., preferably 20 to 30 cm, more preferably 25 to 28 cm, most preferably 25 cm, but it is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0014] As a preferred technical solution of the present invention, the flow rate of the working gas for controlling the spraying is 230-400 L / min, for example, 230 L / min, 240 L / min, 250 L / min, 260 L / min, 270 L / min, 280 L / min, 290 L / min, 300 L / min, 310 L / min, 320 L / min, 330 L / min, 340 L / min, 350 L / min, 360 L / min, 370 L / min, 380 L / min, 390 L / min or 400 L / min, preferably 270-330 L / min, more preferably 290-310 L / min, most preferably 300 L / min, but it is not limited to the listed values, and other unlisted values ​​within the above numerical range are equally applicable.

[0015] As a preferred technical solution of the present invention, the sprayed layer having an average roughness Ra ≥ 22 μm is formed, for example, 22 μm, 22.5 μm, 23 μm, 23.5 μm, 24 μm, 24.5 μm, 25 μm, 25.5 μm, 26 μm, 26.5 μm, 27 μm, 27.5 μm, 28 μm, 28.1 μm, 28.2 μm, 28.3 μm or 28.4 μm, but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0016] As a preferred technical solution of the present invention, the material for the spraying includes aluminum or aluminum alloy.

[0017] As a preferred technical solution of the present invention, the voltage and current of the melt spraying are controlled to adjust the temperature of the melting area so that the melt sprayed material reaches a viscosity level that does not clog the nozzle before the melt spraying is performed.

[0018] As a preferred technical solution of the present invention, the angle between the spraying direction of the spraying and the surface to be treated is controlled to be 60-90°, for example, 60°, 62°, 65°, 68°, 70°, 73°, 75°, 78°, 80°, 82°, 85°, 88° or 90°, etc., preferably 80-90°, more preferably 90°, but not limited to the listed values, other values ​​not listed within the above numerical range are also applicable.

[0019] As a preferred technical solution of the present invention, the pressure of the working gas for controlling the spraying is 0.5-1 MPa, for example, 0.5 MPa, 0.52 MPa, 0.55 MPa, 0.58 MPa, 0.6 MPa, 0.63 MPa, 0.65 MPa, 0.68 MPa, 0.7 MPa, 0.73 MPa, 0.75 MPa, 0.78 MPa, 0.8 MPa, 0.83 MPa, 0.85 MPa, 0.88 MPa, 0.9 MPa, 0.93 MPa, 0.95 MPa, 0.98 MPa or 1 MPa, etc., preferably 0.6-0.7 MPa, more preferably 0.8 MPa, but not limited to the listed values, other values ​​not listed within the above numerical range are equally applicable.

[0020] As a preferred technical solution of the present invention, the working gas includes compressed air.

[0021] As a preferred technical solution of the present invention, the thickness of the sprayed layer is 1 to 3 mm, for example, 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2 mm, 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm or 3 mm, but is not limited to the listed values, and other unlisted values ​​within the above numerical range are also applicable.

[0022] As a preferred technical solution of the present invention, the spraying process method includes: using aluminum or aluminum alloy as the spraying material, controlling the voltage and current of the spraying to adjust the temperature of the molten area, so that the sprayed material reaches a viscosity level that does not clog the nozzle; controlling the vertical distance between the spraying nozzle and the surface to be treated to be 20 to 35 cm, controlling the angle between the spraying direction of the spraying and the surface to be treated to be 60 to 90°, controlling the pressure of the working gas of the spraying to be 0.5 to 1 MPa, and controlling the flow rate of the working gas of the spraying to be 230 to 400 L / min, performing spraying to form a spraying layer with a thickness of 0.01 to 3 mm and an average roughness Ra ≥ 22 μm.

[0023] In a second aspect, the present invention provides a metal target material, wherein the surface of the metal target material is subjected to spraying treatment using the spraying process method described in the first aspect.

[0024] Compared with the prior art solutions, the present invention has at least the following beneficial effects:

[0025] The spraying process method of the present invention adopts a specific vertical distance between the nozzle and the surface to be processed, that is, the nozzle height, and cooperates with the flow rate of a specific working gas, so that the average roughness Ra of the surface of the sprayed layer after spraying can reach 22μm or more, and can reach up to 28μm or more, which gives full play to the value of spraying and greatly improves the upper limit of the roughness of spraying. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0027] It should be clear to those skilled in the art that the embodiments are only intended to help understand the present invention and should not be considered as specific limitations of the present invention.

[0028] In some specific embodiments, the present invention provides a spraying process method for increasing surface roughness, the spraying process method comprising: controlling the vertical distance between the spraying nozzle and the surface to be treated to be 20 to 35 cm, controlling the flow rate of the spraying working gas to be 230 to 400 L / min, performing spraying to form a spraying layer with an average roughness Ra ≥ 22 μm.

[0029] In one embodiment, the spraying process further comprises: controlling the vertical distance between the spraying nozzle and the surface to be processed to be 20 to 30 cm, preferably 25 to 28 cm, and more preferably 25 cm.

[0030] In one embodiment, the spraying process further comprises: controlling the flow rate of the spraying working gas to be 270 to 330 L / min, preferably 290 to 310 L / min, and more preferably 300 L / min.

[0031] In one embodiment, the sprayed material includes aluminum or an aluminum alloy.

[0032] In one embodiment, the melt spraying process further includes: controlling the voltage and current of the melt spraying to adjust the temperature of the melting area so that the melt sprayed material reaches a viscosity level that does not clog the nozzle, and then performing the melt spraying.

[0033] In one embodiment, the thermal spraying process further comprises: controlling the angle between the spraying direction of the thermal spraying and the surface to be processed to be 60 to 90°, preferably 80 to 90°, and more preferably 90°.

[0034] In one embodiment, the spraying process further comprises: controlling the pressure of the spraying working gas to be 0.5 to 1 MPa, preferably 0.6 to 0.7 MPa, and more preferably 0.8 MPa.

[0035] In one embodiment, the thickness of the sprayed layer is 0.01 to 3 mm.

[0036] In some specific embodiments, the present invention provides a metal target material, the surface of which is subjected to spraying treatment using the spraying process method provided in the above embodiments.

[0037] Example 1

[0038] The present embodiment provides a thermal spraying process method for increasing surface roughness, and the thermal spraying process method includes: using one side of a metal target as a surface to be processed; using aluminum as a material for thermal spraying, controlling the voltage and current of the thermal spraying to adjust the temperature of the molten area to 660°C, so that the thermal spraying material reaches a viscosity level that does not clog the nozzle; controlling the vertical distance between the thermal spraying nozzle and the surface to be processed to be 20 cm (i.e., the nozzle height), controlling the angle between the spraying direction of the thermal spraying and the surface to be processed to be 90°, controlling the pressure of the thermal spraying working gas to be 0.8 MPa, and controlling the flow rate of the thermal spraying working gas to be 400 L / min, performing thermal spraying to form a thermal spraying layer with a thickness of 2 mm.

[0039] Example 2

[0040] This embodiment provides a spraying process method for increasing surface roughness. The spraying process method adjusts the vertical distance between the nozzle and the surface to be processed from 20 cm to 25 cm. Except for the above, other conditions are exactly the same as those in Example 1.

[0041] Example 3

[0042] This embodiment provides a spraying process method for increasing surface roughness. The spraying process method adjusts the vertical distance between the nozzle and the surface to be processed from 20 cm to 30 cm. Except for the above, other conditions are exactly the same as those in Example 1.

[0043] Example 4

[0044] This embodiment provides a spraying process method for increasing surface roughness. The spraying process method adjusts the vertical distance between the nozzle and the surface to be processed from 20 cm to 35 cm. Except for the above, other conditions are exactly the same as those in Example 1.

[0045] Example 5

[0046] This embodiment provides a thermal spraying process method for increasing surface roughness. The thermal spraying process method adjusts the flow rate of the working gas from 400 L / min to 300 L / min. Except for the above, other conditions are exactly the same as those in Example 1.

[0047] Example 6

[0048] This embodiment provides a spraying process method for increasing surface roughness. The spraying process method adjusts the vertical distance between the nozzle and the surface to be processed from 20 cm to 25 cm, and adjusts the flow rate of the working gas from 400 L / min to 300 L / min. Except for the above, other conditions are exactly the same as those in Example 1.

[0049] Example 7

[0050] This embodiment provides a spraying process method for increasing surface roughness. The spraying process method adjusts the vertical distance between the nozzle and the surface to be treated from 20 cm to 30 cm, and adjusts the flow rate of the working gas from 400 L / min to 300 L / min. Except for the above, other conditions are exactly the same as those in Example 1.

[0051] Example 8

[0052] This embodiment provides a spraying process method for increasing surface roughness. The spraying process method adjusts the vertical distance between the nozzle and the surface to be processed from 20 cm to 35 cm, and adjusts the flow rate of the working gas from 400 L / min to 300 L / min. Except for the above, other conditions are exactly the same as those in Example 1.

[0053] Example 9

[0054] This embodiment provides a thermal spraying process method for increasing surface roughness. The thermal spraying process method adjusts the thickness of the thermal spraying layer from 2 mm to 0.5 mm. Except for the above, other conditions are exactly the same as those in Example 6.

[0055] Example 10

[0056] This embodiment provides a thermal spraying process method for increasing surface roughness. The thermal spraying process method adjusts the thickness of the thermal spraying layer from 2 mm to 1 mm. Except for the above, other conditions are exactly the same as those in Example 6.

[0057] Embodiment 11

[0058] This embodiment provides a thermal spraying process method for increasing surface roughness. The thermal spraying process method adjusts the thickness of the thermal spraying layer from 2 mm to 3 mm. Except for the above, other conditions are exactly the same as those in Example 6.

[0059] Example 12

[0060] This embodiment provides a thermal spraying process method for increasing surface roughness. The thermal spraying process method adjusts the thickness of the thermal spraying layer from 2 mm to 5 mm. Except for the above, other conditions are exactly the same as those in Example 6.

[0061] Embodiment 13

[0062] This embodiment provides a melt spraying process method for increasing surface roughness. The melt spraying process method adjusts the angle between the spraying direction of the melt spraying and the surface to be processed from 90° to 45°. Except for the above, other conditions are exactly the same as those in Example 6.

[0063] Embodiment 14

[0064] This embodiment provides a spraying process method for increasing surface roughness. The spraying process method adjusts the angle between the spraying direction of the spraying and the surface to be processed from 90° to 60°. Except for the above, other conditions are exactly the same as those in Example 6.

[0065] Embodiment 15

[0066] This embodiment provides a spraying process method for increasing surface roughness. The spraying process method adjusts the angle between the spraying direction of the spraying and the surface to be processed from 90° to 75°. Except for the above, other conditions are exactly the same as those in Example 6.

[0067] Comparative Example 1-Comparative Example 28

[0068] Comparative Examples 1 to 28 respectively provide a spraying process method, in which the vertical distance between the nozzle and the surface to be processed is adjusted, and the flow rate of the working gas is adjusted at the same time, as shown in Table 1.

[0069] The surface roughness of the sprayed layer after spraying of the embodiment and the comparative example was tested using a Mitutoyo (SJ-210) roughness meter; the detection parameters were set as follows: λc was 0.8, the detection distance was 5 mm, the detection was performed at 25°C and 70% humidity, and the detection needle was placed on the sprayed surface for detection. The results are shown in Table 1.

[0070] Table 1

[0071]

[0072]

[0073] It can be seen from Table 1 that:

[0074] Comparison of Comparative Examples 4, 10, 16, and 26 with Example 6 shows that the lower the air pressure of the melt spraying, the greater the surface roughness after the melt spraying, but too low air pressure (Comparative Example 26) is easy to clog the nozzle, which is not conducive to continuous processing. Low air pressure means that the impact force of the melt spraying material on the surface to be processed is smaller, the smaller the impact force, the sharper the melt spraying material, the greater the impact force, and the melt spraying material is easy to become a "pancake" shape after the collision, so the roughness is low.

[0075] Comparative Examples 21, 22, Examples 5, 6, 7, and 8 show that the roughness is higher when the nozzle is 25 mm away from the surface to be treated. If the nozzle is too close, the cooling time for the spray material is insufficient, so that the spray material is still in a liquid state when it hits the surface to be treated, so the spray material is more likely to form a "pancake" shape, so the roughness will be lower; the appropriate distance (meaning that the problem when the material hits the surface to be treated is appropriate) combined with the force provided by the air pressure can make the spray material form a sharp spray surface, so that the roughness can be significantly improved.

[0076] From the above, it can be seen that the spraying process method of the present invention can make the average roughness of the surface of the sprayed layer after spraying Ra ≥ 22μm, and can reach up to 28μm or more by adopting a specific vertical distance between the nozzle and the surface to be treated, that is, the nozzle height, and coordinating with a specific flow rate of working gas, thereby giving full play to the value of spraying and greatly improving the upper limit of the roughness of spraying.

[0077] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0078] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0079] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for increasing surface roughness by thermal spraying, characterized in that: The spraying process comprises: controlling the vertical distance between the spraying nozzle and the surface to be processed to be 20-35 cm, controlling the flow rate of the spraying working gas to be 230-400 L / min, performing spraying, and forming a spraying layer with an average roughness Ra≥22 μm.

2. A method for increasing surface roughness by thermal spraying according to claim 1, characterized in that: The vertical distance between the spray nozzle and the surface to be treated is controlled to be 20 to 30 cm, preferably 25 to 28 cm, and more preferably 25 cm.

3. A method for increasing surface roughness by thermal spraying according to claim 1 or 2, characterized in that: The flow rate of the working gas for controlling the thermal spraying is 270 to 330 L / min, preferably 290 to 310 L / min, and more preferably 300 L / min.

4. A method for increasing surface roughness by thermal spraying according to any one of claims 1 to 3, characterized in that: The material for the spraying includes aluminum or aluminum alloy.

5. A method for increasing surface roughness by thermal spraying according to any one of claims 1 to 4, characterized in that: The voltage and current of the spraying are controlled to adjust the temperature of the melting area so that the sprayed material reaches a viscosity level that does not clog the nozzle, and then the spraying is performed.

6. A method for increasing surface roughness by thermal spraying according to any one of claims 1 to 5, characterized in that: The angle between the spraying direction of the spraying and the surface to be processed is controlled to be 60 to 90°, preferably 80 to 90°, and more preferably 90°.

7. A method for increasing surface roughness by thermal spraying according to claim 1, characterized in that: The pressure of the working gas for controlling the thermal spraying is 0.5 to 1 MPa, preferably 0.6 to 0.7 MPa, and more preferably 0.8 MPa.

8. A method for increasing surface roughness by thermal spraying according to claim 1, characterized in that: The thickness of the sprayed layer is 1 to 3 mm.

9. A method for increasing surface roughness by thermal spraying according to claim 1, characterized in that: The spraying process method comprises: using aluminum or aluminum alloy as the spraying material, controlling the voltage and current of the spraying to adjust the temperature of the melting area, so that the sprayed material reaches a viscosity level that does not clog the nozzle; controlling the vertical distance between the spraying nozzle and the surface to be processed to be 20-35 cm, controlling the angle between the spraying direction of the spraying and the surface to be processed to be 60-90°, controlling the pressure of the working gas of the spraying to be 0.5-1 MPa, controlling the flow rate of the working gas of the spraying to be 230-400 L / min, performing spraying, and forming a spraying layer with a thickness of 0.01-3 mm and an average roughness Ra ≥ 22 μm.

10. A metal target material, characterized in that: The surface of the metal target is subjected to spraying treatment using the spraying process method described in any one of claims 1 to 9.

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