Composite coating, method for producing the same, and composite conductor

Abstract

The application discloses a composite coating, a preparation method thereof and a composite conductor. The composite coating comprises metal and carbon material, and the carbon material comprises graphene. The graphene comprises graphene sheets distributed at different angles with a plane where the composite coating is located. The graphene sheets at least comprise first graphene sheets and second graphene sheets. An angle beta1 of the first graphene sheets with the plane where the composite coating is located is 0 degree, and an angle beta2 of the second graphene sheets with the plane where the composite coating is located is 0 degree < beta2 <= 20 degrees. The graphene in the composite coating is uniformly and orderly distributed, and the composite conductor comprising the composite coating has excellent electrical conductivity and thermal conductivity.

Description

Technical Field

[0001] This invention relates to a composite coating, its preparation method, and a composite conductor. Background Technology

[0002] Graphene possesses numerous advantages, such as high electrical and thermal conductivity, high strength, high flexibility, strong chemical inertness, and excellent gas barrier properties, making it a promising material for many applications. Incorporating graphene into metal coatings can provide high-performance composite graphene conductors.

[0003] Existing technologies typically employ electroplating, vapor deposition, or powder mixing to prepare composite graphene-copper conductors, where graphene and copper are uniformly mixed to form a composite material. However, all existing preparation methods involve some degree of damage to the graphene layer structure. Although electroplating involves less external force during the preparation process, it cannot avoid the presence of agglomerated graphene in the plating solution, resulting in agglomerated graphene in the plating layer.

[0004] CN118957712A discloses an electroplating apparatus and method. By incorporating an energized coil in the electroplating apparatus, the uniform distribution of graphene in the electroplating solution is promoted. When energized, the first coil generates a first magnetic field approximately parallel to the current direction. During electroplating, the current flow in the electroplating solution relies on ion transfer. When ions encounter obstacles such as graphene during their movement, the local direction of ion movement changes, generating a current that is not parallel to the original current direction. Under the influence of the first magnetic field, new magnetic field lines are generated. Under the influence of the Lorentz force, eddy currents are generated near the graphene obstacle, achieving local stirring of the electroplating solution near the graphene. This stirring not only disperses the graphene but also promotes its uniform distribution in the electroplating solution, improving the dispersion stability of graphene in the electroplating solution. Furthermore, a third coil (perpendicular to the current direction and perpendicular to the bottom of the tank) is set near the cathode. The third coil generates a magnetic field during the energization process. During the process of metal ions gaining electrons to reduce metal, the magnetic field is applied from different directions of the cathode. This not only further refines the metal grains, but also allows the metal ions to gain electrons and reduce the metal to arrange the metal in the optimal conductivity order.

[0005] However, the aforementioned method results in a significant shift in the distribution angle between the graphene sheets and the cathode after migration, leading to a rather chaotic arrangement of the graphene sheets in the coating. Furthermore, the time lag in migration causes a large angular distribution between the graphene sheets and the workpiece to be coated, preventing the graphene from maximizing its advantages. Therefore, how to prepare graphene copper coatings using electroplating with a uniform and orderly distribution of graphene remains a challenging research problem. The randomness of graphite distribution in the coating also results in unstable performance of the graphene conductors obtained using this method, with significant batch-to-batch variations. Summary of the Invention

[0006] To address the problem of achieving a uniform and orderly distribution of graphene in the coating when preparing graphene composite conductors using electroplating methods in the prior art, this invention provides a composite coating, its preparation method, and a composite conductor. The composite coating of this invention exhibits a uniform and orderly distribution of graphene.

[0007] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0008] The present invention also provides a composite coating comprising: a metal and a carbon material, wherein the carbon material includes graphene;

[0009] The graphene comprises graphene sheets distributed at different angles to the plane of the composite coating. The graphene sheets include at least a first graphene sheet and a second graphene sheet. The angle β1 between the first graphene sheet and the plane of the composite coating is 0°, and the angle β2 between the second graphene sheet and the plane of the composite coating is 0° < β2 ≤ 20°.

[0010] In this invention, the first graphene sheet accounts for 20%-40% of the mass percentage of the graphene, for example, 20%, 27%, 30%, 32%, 33%, 34%, 35%, 38% or 40%.

[0011] In this invention, the second graphene sheet accounts for 30%-50% of the mass percentage of the graphene, for example, 30%, 37%, 38%, 39%, 40%, 41%, 42%, 48% or 50%.

[0012] In this invention, preferably, the graphene further includes a third graphene sheet, and the angle β3 between the plane of the third graphene sheet and the plane of the composite coating is 70°≤β2≤90°.

[0013] The third graphene sheet accounts for 10%-25% of the total mass of the graphene, preferably 10%-15%; for example, 10%, 12%, 13%, 14%, 15%, 18%, 20% or 25%.

[0014] In some preferred embodiments of the present invention, the graphene includes a first graphene sheet, a second graphene sheet, and a third graphene sheet, wherein the first graphene sheet accounts for 20%-40% of the mass percentage of the graphene, the second graphene sheet accounts for 30%-50% of the mass percentage of the graphene, and the third graphene sheet accounts for 10%-15% of the mass percentage of the graphene.

[0015] In this invention, preferably, the carbon material accounts for 1.0%-5.0% of the mass percentage of the composite coating, for example, 4.0%.

[0016] In this invention, preferably, the graphene accounts for 50%-95% of the mass percentage of the carbon material, for example, 92%.

[0017] In this invention, preferably, the metal includes copper, nickel, silver, or a copper-tin alloy.

[0018] The present invention provides a method for preparing the composite coating, which includes the following steps: placing the part to be plated in an electroplating solution for electroplating, the electroplating solution including metal salt and graphene; applying a first magnetic field and a second magnetic field during the electroplating process, the first magnetic field and the second magnetic field having opposite directions; and applying the first magnetic field and the second magnetic field intermittently and complementaryly in a cyclic manner.

[0019] In some preferred embodiments of the present invention, the composite coating is applied using an electroplating apparatus, the electroplating apparatus comprising:

[0020] Electroplating tank;

[0021] An anode and a cathode are located in the electroplating tank and are arranged opposite to each other along a first direction;

[0022] A first coil, located in the electroplating tank, generates a first magnetic field whose direction makes an angle of 0-10° with the first direction when energized; and

[0023] The second coil is located in the electroplating tank and is located on the side closer to the cathode. The second magnetic field generated by the second coil after being energized at least partially covers the cathode. The magnetic field direction of the second magnetic field generated by the second coil after being energized is at an angle of 0-10° with the second direction, wherein the second direction is perpendicular to the first direction and parallel to the bottom surface of the electroplating tank.

[0024] In this invention, the magnetic field direction of the first magnetic field generated after the first coil is energized is at an angle of, for example, 5° with the first direction.

[0025] Optionally, in this invention, the first coil is located between the anode and the cathode.

[0026] Optionally, in this invention, the first coil is located on the side of the anode away from the cathode.

[0027] Optionally, the number of the first coils in this invention may be one or more.

[0028] In some embodiments of the present invention, there are multiple first coils, and the multiple first coils are arranged along the first direction.

[0029] In some embodiments of the present invention, there are multiple first coils, and the multiple first coils are arranged along the second direction.

[0030] Optionally, in this invention, the first coil is located on the same plane as the anode and the cathode.

[0031] Optionally, in this invention, the ratio of the vertical distance between the center of the first coil and the anode to the vertical distance between the center of the first coil and the cathode is 1:(0.5-0.9), for example, 1:0.8. Here, the center of the first coil refers to a position on the axis of the cylinder formed by the winding of the first coil that is equidistant from both sides of the first coil.

[0032] Optionally, in this invention, the ratio of the depth of the center of the first coil to the depth of the bottom of the anode is (1-2):1, for example, 1.5:1. The depth of the center of the first coil refers to the vertical distance from the center of the first coil to the bottom surface of the electroplating tank, and the depth of the bottom of the anode refers to the vertical distance from the bottom of the anode to the bottom surface of the electroplating tank.

[0033] In this invention, the angle between the magnetic field direction of the second magnetic field generated after the second coil is energized and the second direction is, for example, 5°.

[0034] Optionally, the number of the second coils in this invention may be one or more.

[0035] In some embodiments of the present invention, there are multiple second coils, and the multiple second coils are arranged in parallel along the cathode extension direction.

[0036] In some embodiments of the present invention, there are multiple second coils, and the multiple second coils are arranged in parallel along the first direction.

[0037] In some embodiments of the present invention, there are multiple second coils, which are arranged opposite each other on both sides of the cathode along the second direction.

[0038] Optionally, in this invention, the second coil and the cathode are located on the same plane.

[0039] Optionally, in this invention, the depth ratio of the center of the second coil to the bottom of the cathode is (0.5-1.5):1, for example, 0.8:1. The depth of the center of the second coil refers to the vertical distance from the center of the second coil to the bottom surface of the electroplating tank, and the depth of the bottom of the cathode refers to the vertical distance from the bottom of the cathode to the bottom surface of the electroplating tank.

[0040] In this invention, the electroplating apparatus may further include a first power source, which is used to connect to the first coil.

[0041] In this invention, the electroplating apparatus may further include a second power source, which is used to connect to the second coil.

[0042] In this invention, the electroplating apparatus may further include a third power source, which is used to connect the anode and the cathode.

[0043] Optionally, in this invention, the anode includes a consumable component. The consumable component can be conventional in the art, such as one or more of copper, nickel, silver, tin, palladium, and chromium. The consumable component reacts during the electroplating process to form cations that dissolve in the electroplating solution. These cations then migrate to the cathode and react to form an element. The consumable component ensures a stable cation concentration in the electroplating solution during the electroplating process.

[0044] In some specific embodiments of the present invention, the anode further includes an inert anode, which does not react during the electroplating process. The inert anode may be conventional in the art.

[0045] Optionally, the workpiece to be plated can be conventional in the art, and can be a metal, non-metal, or composite material, such as one or more of copper, aluminum, iron, copper alloys, aluminum alloys, and iron alloys.

[0046] In some specific embodiments of the present invention, the cathode further includes an inert cathode, which does not react during the electroplating process. The inert cathode may be conventional in the art.

[0047] In some preferred embodiments of the present invention, the electroplating method using the above-described electroplating apparatus includes the following steps:

[0048] S1. An electroplating solution is placed in an electroplating tank, and the anode, the cathode, the first coil, and the second coil are immersed in the electroplating solution; wherein, the cathode includes the workpiece to be plated; the electroplating solution includes a metal salt and graphene;

[0049] S2. A first magnetic field is generated by energizing the first coil, a second magnetic field is generated by energizing the second coil, and a third magnetic field is generated by energizing the anode and the cathode to form a composite coating on the surface of the workpiece to be plated; wherein the first and second energizing are intermittently complementary and cyclical, the voltage of the first energizing is a pulse voltage and the magnitude of the first energizing voltage is 250-260V; the voltage of the second energizing is a constant current voltage and the magnitude of the second energizing voltage is 260-280V.

[0050] In this invention, when energized, the magnetic fields generated at adjacent ends of the first coil and the second coil are in opposite directions.

[0051] In this invention, the magnitude of the first energized voltage is, for example, 255V.

[0052] Optionally, in this invention, the magnetic field strength of the first magnetic field is 3-5T, for example, 4T.

[0053] Optionally, in this invention, the frequency of the pulse voltage is 4-6 Hz, for example, 5 Hz.

[0054] In this invention, optionally, the duration of a single energization of the first energization is 3-5 seconds, for example, 4 seconds; the interval duration of the first energization is 3-5 seconds, for example, 4 seconds. The interval duration refers to the time interval between two consecutive energizations.

[0055] In this invention, the magnitude of the second energized voltage is, for example, 270V.

[0056] Optionally, in this invention, the magnetic field strength of the second magnetic field is 4-6T, for example, 5T.

[0057] In this invention, optionally, the duration of a single energization of the second energization is 3-5 seconds, for example, 4 seconds; the interval duration of the second energization is 3-5 seconds, for example, 4 seconds. The interval duration refers to the time interval between two consecutive energizations.

[0058] In some specific embodiments of the present invention, the first energized voltage is a pulse voltage with a frequency of 5Hz, the magnitude of the first energized voltage is 255V, the magnetic field strength of the first magnetic field is 4T, the duration of a single energization is 4s, and the interval between energizations is 4s; the second energized voltage is a constant current voltage, the magnitude of the second energized voltage is 270V, the magnetic field strength of the second magnetic field is 5T, the duration of a single energization is 4s, and the interval between energizations is 4s.

[0059] Optionally, in this invention, the current density generated by the third energization is 0.1-2 A.dm. -2 Preferably, it is 0.3-0.8 A.dm. -2 For example, 0.4A.dm -2 .

[0060] Optionally, the metal salt in this invention includes one or more of copper salt, nickel salt, silver salt, tin salt, palladium salt, and chromium salt.

[0061] Optionally, the copper salt includes one or more of cuprous cyanide, copper sulfate, copper chloride, and copper amine sulfate.

[0062] Optionally, the nickel salt includes one or more of nickel sulfate, nickel chloride, and nickel nitrate.

[0063] Optionally, the silver salt includes one or more of silver nitrate, silver chloride, and aminosilver nitrate.

[0064] Optionally, the tin salt includes one or more of tin chloride, tin sulfate, and tin aminosulfate.

[0065] Optionally, the palladium salt includes one or more of palladium chloride, palladium sulfate, palladium nitrate, and palladium acetate.

[0066] Optionally, the chromium salt includes sodium chromate and / or chromic anhydride.

[0067] In this invention, optionally, the mass concentration of the graphene is 0.5-3 g / L, more preferably 0.5-1.5 g / L, for example 1.0 g / L.

[0068] In some preferred embodiments of the present invention, the metal salt includes a copper salt.

[0069] In the above embodiments, the mass concentration of the copper salt is 5-380 g / L, preferably 50-70 g / L, for example 60 g / L.

[0070] In the above embodiments, the electroplating solution further includes an anodic activator, which is preferably sodium potassium tartrate; the mass concentration of the anodic activator is preferably 15-30 g / L, for example 20 g / L.

[0071] In the above embodiment, the electroplating solution also includes KCN, and the mass concentration of KCN is preferably 100-130 g / L, for example 120 g / L.

[0072] In the above embodiment, the electroplating solution also includes KOH, and the mass concentration of the KOH is preferably 10-20 g / L, for example 15 g / L.

[0073] In the above embodiments, the pH of the electroplating solution can be 8.2-8.8, for example, 8.5.

[0074] In the above embodiments, the temperature of the electroplating solution is 20-30°C, for example, 25°C.

[0075] In some specific embodiments of the present invention, the electroplating solution includes cuprous cyanide, potassium sodium tartrate, KCN, and KOH.

[0076] In a more specific embodiment of the present invention, the electroplating solution comprises graphene at a mass concentration of 1 g / L, cuprous cyanide at a mass concentration of 60 g / L, KCN at a mass concentration of 120 g / L, KOH at a mass concentration of 15 g / L, and sodium potassium tartrate at a mass concentration of 20 g / L, and has a pH of 8.5.

[0077] The present invention also provides a composite coating, which is prepared by the electroplating method described above.

[0078] The present invention also provides a composite conductor comprising a substrate layer and a composite plating layer located on at least one surface of the substrate layer, wherein the composite plating layer is as described above.

[0079] In this invention, the substrate layer can be conventional in the art, such as copper, aluminum, iron, copper alloy, aluminum alloy or iron alloy.

[0080] In this invention, the substrate layer can be the workpiece to be plated as described above.

[0081] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0082] The reagents and raw materials used in this invention are all commercially available.

[0083] The positive and progressive effects of this invention are as follows:

[0084] In the composite coating described in this invention, the graphene sheets are mostly uniformly and regularly distributed within the coating, resulting in a composite conductor with excellent electrical and thermal conductivity. Furthermore, the graphene conductor obtained by this invention exhibits stable performance with minimal batch-to-batch variation. Attached Figure Description

[0085] Figure 1 This is a schematic diagram of the electroplating apparatus of the present invention.

[0086] Figure label:

[0087] 10-Electroplating tank, 11-Electroplating solution, 12-Plastering solution surface, 21-Anode, 22-Cathode, 31-First coil, 32-Second coil, 41-First power supply, 42-Second power supply, 43-Third power supply. Detailed Implementation

[0088] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0089] Example 1

[0090] A schematic diagram of the electroplating apparatus used in Example 1 is shown below. Figure 1 As shown, the electroplating apparatus includes:

[0091] Electroplating tank 10, which is used to hold electroplating solution 11;

[0092] Anode 21 and cathode 22, and a third power supply 43 connecting the anode and cathode; anode 21 and cathode 22 are located in electroplating tank 10 and are arranged opposite to each other along a first direction; anode 21 is a consumable copper electrode, and cathode 22 is a copper rod to be plated;

[0093] A first coil 31 and a first power supply 41 connected to the first coil 31; the first coil 31 is located in the electroplating tank 10 and between the anode 21 and the cathode 22. The magnetic field direction of the first magnetic field generated by the first coil 31 after being energized is parallel to the first direction (i.e., the angle between the first coil 31 and the first direction is 0°, and the first direction is the current direction); the ratio of the vertical distance between the center of the first coil 31 and the anode 21 to the vertical distance between the center of the first coil 31 and the cathode 22 is 1:0.8, and the ratio of the depth of the center of the first coil 31 to the depth of the bottom of the anode 21 is 1.5:1.

[0094] A second coil 32 and a second power supply 42 connected to the second coil 32; the second coil 32 is located in the electroplating tank 10, on the side close to the cathode 22, and on the same plane as the cathode 22; the second magnetic field generated by the second coil 32 after being energized at least partially covers the cathode 22, and the magnetic field direction of the second magnetic field is parallel to the second direction (i.e., the angle between the second magnetic field and the second direction is 0°, the second direction is perpendicular to the first direction and parallel to the bottom surface of the electroplating tank 10 and the plating liquid surface 12); the depth ratio of the center of the second coil 32 to the bottom depth of the cathode 22 is 0.8:1.

[0095] The electroplating solution used in this embodiment includes: graphene with a mass concentration of 1 g / L, cuprous cyanide with a mass concentration of 60 g / L, KCN with a mass concentration of 120 g / L, KOH with a mass concentration of 15 g / L, and potassium sodium tartrate with a mass concentration of 20 g / L, and a pH of 8.5.

[0096] The electroplating method using this electroplating apparatus includes the following steps:

[0097] S1. An electroplating solution 11 at 25°C is placed in an electroplating tank 10, and the anode 21, cathode 22, first coil 31 and second coil 32 are immersed in the electroplating solution 11.

[0098] S2. When current is applied to anode 21 and cathode 22, the resulting current density is 0.4 A·dm³. -2 The first coil 31 is energized for the first time, and the second coil 32 is energized for the second time. The first and second energizations are performed intermittently and in a complementary cycle to form a graphene-copper composite coating on the surface of the workpiece to be plated.

[0099] Among them, the voltage of the first energization is a pulse voltage with a frequency of 5Hz, the magnitude of the voltage of the first energization is 255V, the magnetic field strength of the first magnetic field generated by the first coil 31 is 4T, the duration of the first energization is 4s, and the interval duration of the first energization is 4s.

[0100] The second energizing voltage is a constant current voltage, the magnitude of the second energizing voltage is 270V, the magnetic field strength of the second magnetic field generated by the second coil 32 is 5T, the duration of a single energizing is 4s, and the interval between energizing is 4s.

[0101] The composite conductor prepared by this electroplating method includes a substrate layer (i.e., copper to be plated) and a graphene-copper composite coating on one surface of the substrate layer, wherein the graphene is uniformly and orderly distributed in the graphene-copper composite coating.

[0102] Example 2

[0103] The electroplating apparatus of Example 2 differs from that of Example 1 only in that the magnetic field direction of the first magnetic field generated after the first coil 31 is energized is 5° with the first direction; the other conditions are the same as those of Example 1.

[0104] The electroplating solution and electroplating method in Example 2 are the same as in Example 1. A composite conductor is prepared by this electroplating method, which includes a substrate layer (i.e., copper to be plated) and a graphene-copper composite coating on one surface of the substrate layer, wherein the graphene is uniformly and orderly distributed in the graphene-copper composite coating.

[0105] Example 3

[0106] The electroplating apparatus of Example 3 differs from that of Example 1 only in that the magnetic field direction of the first magnetic field generated after the first coil 31 is energized is 10° with the first direction; the other conditions are the same as in Example 1.

[0107] The electroplating solution and electroplating method in Example 3 are the same as in Example 1. A composite conductor is prepared by this electroplating method, which includes a substrate layer (i.e., copper to be plated) and a graphene-copper composite coating on one surface of the substrate layer, wherein the graphene is uniformly and orderly distributed in the graphene-copper composite coating.

[0108] Example 4

[0109] The electroplating apparatus of Example 4 differs from that of Example 1 only in that the angle between the magnetic field direction of the second magnetic field generated after the second coil 32 is energized and the second direction is 5°; the other conditions are the same as those of Example 1.

[0110] The electroplating solution and electroplating method in Example 4 are the same as in Example 1. A composite conductor is prepared by this electroplating method, which includes a substrate layer (i.e., copper to be plated) and a graphene-copper composite coating on one surface of the substrate layer, wherein the graphene is uniformly and orderly distributed in the graphene-copper composite coating.

[0111] Example 5

[0112] The electroplating apparatus of Example 5 differs from that of Example 1 only in that the angle between the magnetic field direction of the second magnetic field generated after the second coil 32 is energized and the second direction is 10°; the other conditions are the same as those of Example 1.

[0113] The electroplating solution and electroplating method in Example 5 are the same as in Example 1. A composite conductor is prepared by this electroplating method, which includes a substrate layer (i.e., copper to be plated) and a graphene-copper composite coating on one surface of the substrate layer, wherein the graphene is uniformly and orderly distributed in the graphene-copper composite coating.

[0114] Comparative Example 1

[0115] The electroplating apparatus of Comparative Example 1 differs from that of Example 1 in that the angle between the direction of the first magnetic field generated after the first coil 31 is energized and the first direction is 15°. The other conditions are the same as in Example 1.

[0116] The electroplating solution and electroplating method of Comparative Example 1 are the same as those of Example 1.

[0117] Comparative Example 2

[0118] The electroplating apparatus of Comparative Example 2 differs from that of Example 1 in that the angle between the direction of the second magnetic field generated by the second coil 32 after energization and the second direction is 15°. All other conditions are the same as in Example 1.

[0119] The electroplating solution and electroplating method of Comparative Example 2 are the same as those of Example 1.

[0120] Comparative Example 3

[0121] In Comparative Example 3, a conventional electroplating apparatus was used, i.e., the first coil 31 and the second coil 32 were not set; the other conditions were the same as in Example 1.

[0122] The electroplating solution of Comparative Example 3 is the same as that of Example 1.

[0123] The electroplating method using this electroplating system includes the following steps:

[0124] S1. An electroplating solution at 25°C is placed in an electroplating tank, and the anode and cathode are immersed in the electroplating solution.

[0125] S2. When current is applied to the anode and cathode, the resulting current density is 0.4 A·dm³. -2 To form a graphene-copper composite coating on the surface of the part to be plated.

[0126] Comparative Example 4

[0127] In Comparative Example 4, in step S2 of the electroplating method, the voltage of the second energization is 240V, and the magnetic field strength of the second magnetic field generated by the second coil is 0.5T; the other conditions are the same as in Example 1.

[0128] Comparative Example 5

[0129] In Comparative Example 5, in step S2 of the electroplating method, the second energized voltage is a pulse voltage; the other conditions are the same as in Example 1.

[0130] Example 1

[0131] The composite coating structures of the composite conductors prepared in the above embodiments and comparative examples were tested. The parameters of the graphene layer in the composite coating are listed in Table 1. The testing methods for each parameter are conventional in the art.

[0132] Table 1

[0133]

[0134] In Table 1, graphene sheets with an angle of 0° (β1) to the plane of the composite coating are designated as first graphene sheets; graphene sheets with an angle greater than 0° but not exceeding 20° (β2) to the plane of the composite coating are designated as second graphene sheets; and graphene sheets with an angle between 70° and 90° (β3) to the plane of the composite coating are designated as third graphene sheets. As shown in Table 1, Examples 1-5 of the present invention contain first graphene sheets, while Comparative Examples 1-5 do not. Furthermore, the sum of the contents of the first and second graphene sheets in Examples 1-5 is much higher than that in Comparative Examples 1-5, and the content of the third graphene sheet in Examples 1-5 is much lower than that in Comparative Examples 1-5, indicating that the graphene sheets in the composite coating of the present invention are uniformly and regularly distributed.

[0135] Example 2

[0136] The composite conductors prepared in the above embodiments and comparative examples were tested for electrical conductivity and thermal conductivity. The electrical conductivity was tested using the four-probe method, and the thermal conductivity was tested using the steady-state method (hot wire method).

[0137] The test results are listed in Table 2:

[0138] Table 2

[0139]

[0140] As shown in Table 2, the composite conductor of this invention exhibits excellent electrical conductivity (above 125% IACS) and thermal conductivity (above 415 W / (m•k)). In this invention, a first coil and a second coil are arranged in a specific manner within an electroplating apparatus. The first coil, positioned approximately parallel to the current direction, generates magnetic field lines, controlling the migration of graphene in the electroplating solution towards the cathode. When encountering migrating metal ions, the graphene sheets, having adsorbed some of the metal ions, migrate at a slower rate than the metal ions during migration. Upon collision with the metal ions, they deviate from the current direction. Under the influence of the strong magnetic field generated by the first coil, the graphene sheets are driven to return to the direction of current flow or a smaller angle of migration. The second coil generates a magnetic field on the cathode surface, with the magnetic field direction roughly perpendicular to the current flow direction and approximately parallel to the bottom of the electroplating tank. Metal ions are adsorbed on the graphene sheet surface. When a portion of the graphene sheet reaches the cathode surface of the workpiece to be plated first, while the remaining portion does not, the graphene sheet, cathode, and plating solution form a closed conductive circuit. Under the influence of the magnetic field of the second coil, this closed coil cuts the magnetic field lines, generating a weak voltage that drives the graphene sheet to move rapidly towards the cathode surface. This avoids a large angular distribution between the graphene sheet and the workpiece due to migration time differences. In summary, through the synergistic effect of the first and second coils, the graphene sheet can be mostly uniformly and regularly distributed in the plating layer, resulting in graphene conductors with excellent electrical and thermal conductivity.

[0141] Examples 1-5 of this invention demonstrate that when the angle between the direction of the magnetic field generated by the first coil after energizing and the first direction is 0-10°, and the angle between the direction of the magnetic field generated by the second coil after energizing and the second direction is 0-10°, copper composite conductors with high electrical conductivity (above 125% IACS) and high thermal conductivity (above 415 W / (m•k)) can be obtained, significantly higher than those obtained without coils (as in Comparative Example 3). In Example 1, the direction of the magnetic field generated by the first coil after energizing is parallel to the first direction (current direction), and the direction of the magnetic field generated by the second coil after energizing is parallel to the second direction; the copper composite conductor obtained under these conditions exhibits optimal electrical and thermal conductivity. Comparative Example 3, using a conventional electroplating apparatus without first and second coils, yields the composite conductor with the lowest electrical and thermal conductivity. Comparative Examples 1 and 2 show that if the direction of the magnetic field generated by the first coil after energizing deviates significantly from the first direction, or if the direction of the magnetic field generated by the second coil after energizing deviates significantly from the second direction, the high electrical and thermal conductivity of this invention cannot be obtained. Comparative Example 4 shows that when electroplating is performed using the electroplating apparatus of the present invention, if the second energized voltage is low, the electrical conductivity and thermal conductivity will also decrease significantly. Furthermore, Comparative Example 5 shows that when electroplating is performed using the electroplating apparatus of the present invention, it is necessary to control the second energized voltage to be a constant current voltage; if a pulsed voltage is used, the electrical conductivity and thermal conductivity will decrease significantly.

[0142] Furthermore, the graphene conductors obtained by this invention exhibit stable performance and minimal batch-to-batch variation.

[0143] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A composite coating, characterized in that, It includes: Metals and carbon materials, wherein the carbon materials include graphene; The graphene comprises graphene sheets distributed at different angles to the plane of the composite coating. The graphene sheets include at least a first graphene sheet and a second graphene sheet. The angle β1 between the first graphene sheet and the plane of the composite coating is 0°, and the angle β2 between the second graphene sheet and the plane of the composite coating is 0° < β2 ≤ 20°.

2. The composite coating according to claim 1, characterized in that, The first graphene sheet accounts for 20%-40% of the total mass of the graphene.

3. The composite coating according to claim 1, characterized in that, The second graphene sheet accounts for 30%-50% of the total graphene mass.

4. The composite coating according to claim 1, characterized in that, The graphene sheet also includes a third graphene sheet, and the angle β3 between the third graphene sheet and the plane of the composite coating is 70°≤β2≤90°.

5. The composite coating according to claim 4, characterized in that, The third graphene sheet accounts for 10%-15% of the total mass of the graphene.

6. The composite coating according to any one of claims 1-5, characterized in that, The carbon material accounts for 1.0%-5.0% of the mass of the composite coating; And / or, the graphene accounts for 50%-95% of the mass percentage of the carbon material; And / or, the metal includes copper, nickel, silver, or a copper-tin alloy.

7. A method for preparing a composite coating as described in any one of claims 1-6, characterized in that, It includes the following steps: The part to be plated is placed in an electroplating solution for electroplating, the electroplating solution comprising metal salts and graphene; During the electroplating process, a first magnetic field and a second magnetic field are applied. The magnetic fields of the first magnetic field and the second magnetic field are in opposite directions and are applied intermittently and complementaryly in a cyclical manner.

8. The method for preparing the composite coating according to claim 7, characterized in that, The composite coating is applied using an electroplating apparatus, which includes: Electroplating tank; An anode and a cathode are located in the electroplating tank and are arranged opposite to each other along a first direction; A first coil, located in the electroplating tank, generates a first magnetic field whose direction makes an angle of 0-10° with the first direction when energized; and The second coil is located in the electroplating tank and is located on the side closer to the cathode. The second magnetic field generated by the second coil after being energized at least partially covers the cathode. The magnetic field direction of the second magnetic field generated by the second coil after being energized is at an angle of 0-10° with the second direction, wherein the second direction is perpendicular to the first direction and parallel to the bottom surface of the electroplating tank.

9. The method for preparing the composite coating according to claim 8, characterized in that, The electroplating method using the aforementioned electroplating apparatus includes the following steps: S1. An electroplating solution is placed in an electroplating tank, and the anode, the cathode, the first coil, and the second coil are immersed in the electroplating solution; wherein, the cathode includes the workpiece to be plated; the electroplating solution includes a metal salt and graphene; S2. A first magnetic field is generated by energizing the first coil, a second magnetic field is generated by energizing the second coil, and a third magnetic field is generated by energizing the anode and the cathode to form a composite coating on the surface of the workpiece to be plated; wherein the first and second energizing are intermittently complementary and cyclical, the voltage of the first energizing is a pulse voltage and the magnitude of the first energizing voltage is 250-260V; the voltage of the second energizing is a constant current voltage and the magnitude of the second energizing voltage is 260-280V.

10. A composite conductor, characterized in that, It includes a substrate layer and a composite coating on at least one surface of the substrate layer, the composite coating being the composite coating described in any one of claims 1-6.

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