C-c composite bracket surface conductive coating and preparation and application thereof

Abstract

The application discloses a C-C composite material bracket surface conductive coating and preparation and application thereof, and comprises the following steps: S1, obtaining a C-C composite material bracket with a clean surface; S2, performing sand blasting treatment on the surface of the C-C composite material bracket by using composite sand particles to obtain a roughened C-C composite material bracket, wherein the composite sand particles comprise fine sand with a particle size of 150-220 mesh and coarse sand with a particle size of 12-16 mesh; and S3, spraying a metal layer on the surface of the roughened C-C composite material bracket, and then performing shot blasting treatment on the surface of the metal layer to obtain the C-C composite material bracket surface conductive coating; the coating has good conductivity and strong bonding force.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite materials, and particularly relates to a C-C composite material bracket surface conductive coating and preparation and application thereof. BACKGROUND

[0002] Physical vapor deposition (PVD) technology refers to a technology that under vacuum conditions, a material source (solid or liquid) surface is vaporized into gaseous atoms or molecules, or partially ionized into ions, and through a low-pressure gas (or plasma) process, a thin film with certain special functions is deposited on the surface of a substrate bracket. It is an important technology in the field of chip manufacturing.

[0003] Therefore, the substrate bracket has certain conductivity requirements. In a vacuum coating chamber, a bracket is designed to support the sample. The bracket is generally made of metal material. Metal material is easy to conduct electricity. Applying a negative bias to the bracket is conducive to the deposition of thin film material and improves the quality of the thin film. However, the surface temperature of the bracket in the vacuum chamber during thin film deposition can reach 300 DEG C, which can easily cause thermal deformation of the metal bracket, resulting in a decrease in the quality of the thin film deposition and affecting the final performance of the product. The existing technology uses C-C composite material to make the bracket. The deformation of this material under the action of 300 DEG C high temperature is extremely low, and it is an ideal material for PVD coating bracket. The C-C composite material is made by weaving a carbon fiber preform, impregnating the resin, and then molding. The carbon fiber composite material molded by molding is sintered at high temperature to remove the organic resin. However, the material has poor conductivity, and a negative bias cannot be applied in the coating process. The surface of the C-C bracket needs to be treated to be conductive. Copper and aluminum are metal materials with excellent conductivity and low cost, and are widely used in the manufacture of electrical and circuit equipment. A copper or aluminum coating is prepared on the surface of the C-C composite material bracket to improve the conductivity of the C-C bracket and the stability of the quality of the prepared thin film.

[0004] In the related art, the copper or aluminum coating is prepared on the surface of the CC composite material bracket, and the commonly used methods are flame spraying, arc spraying, and cold spraying. The cold spraying particle velocity is high. Although the low porosity of the coating can improve the conductivity, the high particle velocity will cause the coating stress to be large, and the CC composite material has low hardness and high brittleness. Because the surface of the material is difficult to roughen, the thickness of the cold spray is difficult to make thick (less than 100μm). Otherwise, the coating will fall off or crack due to the weak bonding between the coating and the substrate, and the CC composite material will also be damaged. The spraying particle velocity of flame spraying and arc spraying is low. Compared with cold spraying, the thickness (less than 200μm) prepared by them is thick, which is conducive to the improvement of conductivity. However, the coating obtained by this method has larger pores, especially the large coating thickness will also increase the defect of large porosity, which makes the improvement of conductivity have certain limitations, and the higher the thickness (greater than 200μm), the more likely it is that the coating will fall off or crack. In summary, in the related art, the conductivity and bonding strength of the conductive coating on the surface of the CC composite material bracket need to be improved. Summary of the Invention

[0005] In view of this, the present application provides a CC composite material bracket surface conductive coating and its preparation and application, which has good conductivity and strong bonding force.

[0006] In order to achieve the above technical objectives, this application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a method for preparing a conductive coating on the surface of a CC composite material bracket, comprising the following steps:

[0008] S1. Obtain a clean surface CC composite bracket;

[0009] S2 using composite sand CC composite bracket surface sandblasting, rough CC composite bracket, composite sand including a particle size of 150-220 mesh fine sand and a particle size of 12-16 mesh coarse sand;

[0010] S3. Spraying a metal layer onto the roughened surface of the CC composite bracket, and then performing shot peening on the surface of the metal layer to obtain a conductive coating on the surface of the CC composite bracket.

[0011] Preferably, the pressure of the sandblasting treatment is 0.4-0.6 MPa, and the sandblasting distance is 300-500 mm.

[0012] Preferably, the mass ratio of fine sand to coarse sand is 100:5-10.

[0013] Preferably, the particle size of the steel shot used in the shot peening treatment is 1.4-2.0 mm, the shot peening pressure is 0.4-0.6 MPa, and the shot peening distance is 100-300 mm.

[0014] Preferably, the spraying process of the sprayed metal layer is one or more of cold spraying, flame spraying, and arc spraying.

[0015] Preferably, the spraying path of the sprayed metal layer is transverse spraying overlapping longitudinal spraying.

[0016] Preferably, the metal layer is one or more of a metal aluminum layer, a metal copper layer, an aluminum alloy layer, and a copper alloy layer.

[0017] Preferably, the spraying thickness of the metal layer is 200-300 μm.

[0018] In a second aspect, the present application provides a C-C composite bracket surface conductive coating prepared by the preparation method.

[0019] In a third aspect, the present application provides a use of a C-C composite bracket surface conductive coating in the field of chips.

[0020] The beneficial effects of the present application are as follows:

[0021] The present scheme aims at the problems of low hardness, high brittleness of de-glued C-C composite material, and material damage caused by sand blasting. The composite sand particle mixing method is used for sand blasting, which ensures the sand blasting integrity of the C-C material, improves the material surface roughness and coating adhesion, is conducive to the preparation of a relatively high-thickness coating (200-300 μm) under cold spraying or thermal spraying conditions, and improves the electrical conductivity. On the basis of composite sand blasting-sprayed metal coating, the shot peening method is used to reduce the problem of increased resistivity caused by the increase of voids due to the increase of thickness of the high-porosity metal coating, further improve the electrical conductivity of the coating, and the shot peening produces a certain compressive stress on the coating, which is conducive to the bonding of the coating and the substrate, prevents the coating from falling off and reduces the electrical conductivity. The present scheme uses a mechanical hand to hold a spray gun, sets a spraying path, improves the uniformity of the coating spraying, reduces the risk of cracking and peeling of the coating, and is conducive to spraying a large-thickness coating. The C-C material bracket surface coating of the present application can be replaced regularly, which is convenient for the reuse of C-C composite material in the later stage, saves cost, and is convenient for industrialization. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The figure is a schematic diagram of the spraying path of the present scheme.

[0023] Figure 2 The figure is the surface roughness of the untreated blank C-C composite material substrate.

[0024] Figure 3 The figure is the surface morphology of the material after sand blasting according to the comparative example 1 scheme.

[0025] Figure 4 The figure is the surface morphology of the material after sand blasting according to the embodiment 1 scheme.

[0026] Figure 5 The surface roughness of the material after sand blasting for different particle size sand particles is measured;

[0027] Figure 6 The metallographic photos of the Al coating of the material before and after shot peening in the present scheme, wherein the before shot peening is Figure 6 (a), and the after shot peening is Figure 6 (b). DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application is further described in detail below in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0029] The present application provides a preparation method of a C-C composite bracket surface conductive coating, comprising the following steps:

[0030] S1. Obtain a C-C composite bracket with a clean surface;

[0031] S2. Use composite sand particles to perform sand blasting treatment on the surface of the C-C composite bracket to obtain a roughened C-C composite bracket, wherein the composite sand particles comprise fine sand with a particle size of 150-220 mesh and coarse sand with a particle size of 12-16 mesh;

[0032] S3. Spray a metal layer on the surface of the roughened C-C composite bracket, and then perform shot peening treatment on the surface of the metal layer to obtain a C-C composite bracket surface conductive coating.

[0033] The present application uses composite sand particles for sand blasting treatment, and the impact of fine sand with a size of 150-220 mesh on the C-C composite bracket is weak, so as to ensure the integrity of the surface of the C-C material and enhance the mechanical properties, and the impact of coarse sand with a size of 12-16 mesh on the surface of the material makes the surface of the C-C composite material have a certain roughness, so as to improve the bonding strength of the coating, and the combination of sand particles with different sizes is beneficial to the subsequent continuous spraying of a thick metal coating; it is worth noting that, due to the low hardness and large brittleness of the C-C composite material, sand particles with too large a size cannot be used, and sand particles with a large size and high pressure can damage the substrate by knocking off the C-C composite material during sand blasting, but sand particles with too small a size can make the roughness of the material surface small, and when a high-thickness coating is needed to be sprayed, the bonding ability of the coating and the substrate can cause the coating to fall off, so the size of the sand particles is selected in the range of 12-16 mesh for large-size sand particles and in the range of 150-220 mesh for small-size sand particles. After steps S1 and S2, the subsequent shot blasting treatment is beneficial to reducing the porosity of the thick metal coating (200-300 μm) and further improving the conductivity of the coating, and the shot blasting makes the coating produce a certain compressive stress, which is beneficial to the bonding of the coating and the substrate; and the problems of poor conductivity and low bonding force of the conductive coating on the surface of the C-C composite bracket prepared by cold spraying or thermal spraying of metal are solved.

[0034] The pressure of the sand blasting treatment is 0.4-0.6 MPa, and the sand blasting distance is 300-500 mm. The C-C composite bracket is a large flat plate structure, and can only be slightly sandblasted, otherwise the material will be knocked off due to the impact of the sand particles, and the pressure and distance range defined in the present application can ensure the effectiveness of the sand blasting and will not cause excessive sand blasting.

[0035] The mass ratio of fine sand to coarse sand is 100:5-10, and in this range, the obtained substrate roughness is moderate, which is beneficial to the high-strength bonding of the coating, and if too much coarse sand is used, sand blasting pits will appear, the bracket will be scrapped, and if too much fine sand is used, the roughness will not be enough, which will not obviously enhance the bonding force of the coating.

[0036] The steel shot used for shot blasting has a size of 1.4-2.0 mm, the shot blasting pressure is 0.4-0.6 MPa, and the shot blasting distance is 100-300 mm; when the size of the steel shot is too large, the impact on the coating is large, which can cause the coating to deform and fall off. The impact on the coating is small when the size of the steel shot is small, and the porosity is not obviously reduced.

[0037] The spraying process of the metal layer is one or more of cold spraying, flame spraying and arc spraying, and more preferably, the spraying process of the metal layer is flame spraying and arc spraying, i.e. thermal spraying.

[0038] The spraying path of the metal layer is transverse spraying overlapping longitudinal spraying, and the implementation manner is mechanical hand operation, and the spraying path of the mechanical hand is as shown in Figure 1As shown, the C-C bracket is divided into three regions, and each region is sprayed to avoid coating debonding caused by stress due to continuous spraying of large flat surfaces. First, the robot moves transversely along the C-C composite plate to spray the part, and the coating covers the surface of the part. The next pass uses a longitudinal movement to spray the part, and the coating covers the part twice until the designed thickness is sprayed. The robot is held, and the spraying path is planned to make the coating thickness and structure more uniform. The transverse and longitudinal spraying method reduces the stress of the coating, which is beneficial to the bonding of the coating and the spraying of a higher thickness coating.

[0039] The metal layer is one or more of a metal aluminum layer, a metal copper layer, an aluminum alloy layer, and a copper alloy layer, and the material oxidation amount is low. More preferably, the metal layer is a metal aluminum layer, which provides the coating with electrical conductivity.

[0040] The spraying thickness of the metal layer is 200-300 μm. Below this range, the electrical conductivity continues to improve. Because of the existence of the thermal spraying coating gap, when the coating thickness exceeds 300 μm, the higher the coating thickness, the lower the resistivity. For cold spraying, when the coating thickness exceeds 300 μm, the coating is easily peeled off from the substrate, and the metal layer is easily peeled off.

[0041] The application provides a C-C composite bracket surface conductive coating obtained by the preparation method, and the thickness of the coating is 200-300 μm.

[0042] The application provides an application of the C-C composite bracket surface conductive coating in the chip field.

[0043] The application is further described below through specific examples.

[0044] Example 1

[0045] A preparation method of a C-C composite bracket surface conductive coating, comprising the following steps:

[0046] S1. Cleaning the surface of the C-C composite bracket with alcohol or acetone to remove oil stains and other impurities and obtain a clean C-C composite bracket surface;

[0047] S2. Using composite sand particles to sand blast the surface of the C-C composite bracket to obtain a roughened C-C composite bracket, wherein the composite sand particles include 150-mesh aluminum oxide fine sand and 16-mesh coarse sand; the sand blasting pressure is 0.6 MPa, the sand blasting distance is 500 mm, the mass ratio of the fine sand to the coarse sand is 100:5, and compressed air is used to blow off the residual sand particles and dust on the coating surface after sand blasting. After sand blasting, the sand blasted surface morphology is as shown in Figure 4As shown, the C-C matrix surface is uniform and fully roughened, and no abnormal defects of the material are found; the surface roughness of the untreated blank C-C composite material is as follows Figure 2 As shown, it is shown that the C-C matrix surface has a "steamed bun" shaped fiber weaving morphology, and the "gully" is the lap joint part of the fiber bundle.

[0048] S3. A metal layer 200 μm is sprayed on the roughened C-C composite bracket surface by using a mechanical hand holding a flame or arc spray gun, and the spraying is in a transverse and longitudinal lap joint manner, and then a shot blasting treatment is performed on the surface of the metal layer, the steel shot particle size used for the shot blasting treatment is 1.4 mm, the shot blasting pressure is 0.6 MPa, and the shot blasting distance is 300 mm, thereby obtaining a C-C composite bracket surface conductive coating.

[0049] Example 2

[0050] A preparation method of a C-C composite bracket surface conductive coating is basically the same as that of Example 1, except that a mechanical hand cold spraying method is used in step S3.

[0051] Example 3

[0052] A preparation method of a C-C composite bracket surface conductive coating is basically the same as that of Example 1, except that the surface sprayed metal layer has a thickness of 300 μm in step S3.

[0053] Example 4

[0054] A preparation method of a C-C composite bracket surface conductive coating is basically the same as that of Example 1, except that the surface sprayed metal layer has a thickness of 350 μm in step S3.

[0055] Example 5

[0056] A preparation method of a C-C composite bracket surface conductive coating is basically the same as that of Example 1, except that the composite sand particles include fine sand with a particle size of 220 mesh and coarse sand with a particle size of 12 mesh.

[0057] Example 6

[0058] A preparation method of a C-C composite bracket surface conductive coating is basically the same as that of Example 1, except that the pressure of the sand blasting treatment is 0.4 MPa, the sand blasting distance is 300 mm, the mass ratio of the fine sand to the coarse sand is 100:10, the steel shot particle size used for the shot blasting treatment is 2.0 mm, the shot blasting pressure is 0.4 MPa, and the shot blasting distance is 100 mm.

[0059] Comparative Example 1

[0060] A method for preparing a conductive coating on the surface of a C-C composite bracket is substantially the same as that of Example 1, except that the sand used in the sandblasting treatment is fine sand having a particle size of 150 mesh, and the sandblasted surface morphology is as shown in FIG. 2. Due to the impact of the sand particles, the "steamed bun" shaped protrusions of the fiber bundle are eliminated, the C-C matrix surface is roughened and continuous and uniform, and the depth of the sandblasting "pits" is significantly lower than that when coarse sand is used. Figure 3

[0061] Comparative Example 2

[0062] A method for preparing a conductive coating on the surface of a C-C composite bracket is substantially the same as that of Example 1, except that the sand used in the sandblasting treatment is coarse sand having a particle size of 16 mesh.

[0063] Comparative Example 3

[0064] A method for preparing a conductive coating on the surface of a C-C composite bracket is substantially the same as that of Example 1, except that the composite sand particles include fine sand having a particle size of 320 mesh and coarse sand having a particle size of 8 mesh.

[0065] Comparative Example 4

[0066] A method for preparing a conductive coating on the surface of a C-C composite bracket is substantially the same as that of Example 1, except that the composite sand particles include fine sand having a particle size of 320 mesh and coarse sand having a particle size of 16 mesh

[0067] Comparative Example 5

[0068] A method for preparing a conductive coating on the surface of a C-C composite bracket is substantially the same as that of Example 1, except that the composite sand particles include fine sand having a particle size of 150 mesh and coarse sand having a particle size of 8 mesh

[0069] Comparative Example 6

[0070] A method for preparing a conductive coating on the surface of a C-C composite bracket is substantially the same as that of Example 1, except that the sandblasting treatment is not included.

[0071] Comparative Example 7

[0072] A method for preparing a conductive coating on the surface of a C-C composite bracket is substantially the same as that of Example 2, except that the sandblasting treatment is not included.

[0073] Evaluation Test

[0074] ​The conductive coatings on the surfaces of the CC composite brackets prepared in Examples 1-6 and Comparative Examples 1-7 were subjected to performance testing, and their appearance (whether the CC composite material and coating were damaged) was observed. The conductivity was tested using an ST2263 digital four-probe tester. The coating porosity was calculated using Image-Pro Plus image analysis software. The bonding strength between the coating and the substrate was measured using the bonding tensile method on a universal testing machine at a tensile speed of 1 mm per minute to test the coating bonding strength. The results are shown in Table 1.

[0075] Table 1 Test results

[0076]

[0077] The roughness of the composite sand particles (150-220 mesh alumina sand mixed with 10% to 20% of 12-16 mesh coarse sand), 150-220 mesh alumina sand sandblasting and untreated CC composite material original matrix were tested. The results are as follows: Figure 5 As shown in FIG, when 150-220 mesh sand is used for sandblasting, the surface roughness Ra of the CC substrate is about 25 μm, which is slightly higher than the surface roughness Ra of the original substrate by 20 μm. When 150-220 mesh sand is mixed with 10% to 20% of 12-16 mesh coarse sand for sandblasting, the surface roughness Ra of the substrate increases to about 67 μm. The metallographic structure of the Al layer before and after shot blasting in step S3 of this scheme is tested, and the results are shown in FIG. Figure 6 As shown in the figure, it shows that the Al coating has uniformly distributed pores with a diameter of about 8-10 microns before shot peening; after shot peening, the number of pores in the coating is reduced by about 2 / 3.

[0078] The above are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method of preparing a surface conductive coating for a C-C composite bracket, characterized by, The method comprises the following steps: S1. obtaining a C-C composite bracket with a clean surface; S2. performing sand blasting treatment on the surface of the C-C composite bracket using composite sand particles to obtain a roughened C-C composite bracket, wherein the composite sand particles comprise fine sand with a particle size of 150-220 mesh and coarse sand with a particle size of 12-16 mesh; S3. spraying a metal layer with a thickness of 200-300 μm on the surface of the roughened C-C composite bracket, and then performing shot blasting treatment on the surface of the metal layer to obtain the conductive coating on the surface of the C-C composite bracket. The mass ratio of the fine sand to the coarse sand is 100:5-10; the particle size of the steel shot used in the shot blasting treatment is 1.4-2.0 mm, the shot blasting pressure is 0.4-0.6 MPa, and the shot blasting distance is 100-300 mm; and the spraying path of the metal layer is transverse spraying with longitudinal spraying overlapping.

2. The method of claim 1, wherein the C-C composite bracket surface conductive coating is prepared by the steps of: The pressure of the sand blasting treatment is 0.4-0.6 MPa, and the sand blasting distance is 300-500 mm.

3. The method of claim 1, wherein the C-C composite bracket surface conductive coating is prepared by, The spraying process of the metal layer is one or more of cold spraying, flame spraying and electric arc spraying.

4. The method of claim 1, wherein the C-C composite bracket surface conductive coating is prepared by, The metal layer is one or more of a metal aluminum layer, a metal copper layer, an aluminum alloy layer and a copper alloy layer.

5. A conductive coating on the surface of a C-C composite bracket obtained by the preparation method according to any one of claims 1-4.

6. Application of the conductive coating on the surface of a C-C composite bracket according to claim 5 in the field of chips.

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