Electromagnetic shielding and anti-corrosion integrated functional film for metal substrate and preparation method thereof
By forming a nano-zirconia/graphene composite layer, a MXene/silver nanowire gradient structure and a polytetrafluoroethylene/silicon dioxide coating on the surface of the metal substrate, the problem of electrochemical corrosion of the metal substrate in a humid environment is solved, electromagnetic shielding and anti-corrosion are integrated, the interface bonding strength and shielding effectiveness are improved, and energy consumption and costs are reduced.
Patent Information
- Application Number
- CN202511075109.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-31
- Publication Date
- 2025-10-10
AI Technical Summary
In the existing technology, metal substrates are prone to electrochemical corrosion in humid or salt spray environments, and require additional spraying of organic anti-corrosion coatings, which leads to complex processes and increased costs. There is a lack of integrated electromagnetic shielding and anti-corrosion functional membranes with compact structures, strong interface bonding, and scalable production, resulting in insufficient long-term reliability.
A functional membrane composed of a nano-zirconia/graphene composite layer, a MXene two-dimensional material/silver nanowire gradient structure and a polytetrafluoroethylene/silicon dioxide hybrid coating is used to form a dense, super-hydrophobic structure on the surface of the metal substrate through sol-gel method, magnetron sputtering and plasma polymerization technology, thereby enhancing the interface bonding strength and anti-corrosion performance.
It achieves high reliability of metal substrates in complex environments, reduces energy consumption and costs, improves interface adhesion and corrosion resistance, enhances shielding effectiveness, and significantly improves wear resistance and corrosion resistance.
Smart Images
Figure CN120769487A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of metal substrate functional films, and in particular to an electromagnetic shielding and anti-corrosion integrated functional film for a metal substrate and a preparation method thereof. Background Art
[0002] Metal substrate refers to materials composed mainly of metals or alloys, usually serving as the base layer of structure or function, and is widely used in industries such as industry, construction, electronics, aerospace, etc.
[0003] Metal substrates, when widely used in fields such as electronic equipment, aerospace, and marine engineering, must simultaneously meet the requirements of electromagnetic shielding (EMI shielding) and corrosion resistance. However, in existing technologies, electromagnetic shielding and corrosion resistance are usually achieved through independent coatings or processes. Although traditional metal coatings (such as copper and nickel coatings) can provide electromagnetic shielding, they are prone to electrochemical corrosion when exposed to humid or salt spray environments for a long time, requiring additional spraying of organic anti-corrosion coatings, resulting in complex processes and increased costs. Existing technologies lack a compact structure, strong interface bonding, and scalable integrated electromagnetic shielding and corrosion resistance functional film, resulting in insufficient long-term reliability of metal substrates in complex environments. Summary of the Invention
[0004] The purpose of the present invention is to solve the problem that in the prior art, electromagnetic shielding and anti-corrosion functions are usually achieved through independent coatings or processes. Although traditional metal platings (such as copper and nickel platings) can provide electromagnetic shielding, they are prone to electrochemical corrosion when exposed to humid or salt spray environments for a long time, and additional organic anti-corrosion coatings need to be sprayed, resulting in complex processes and increased costs. The prior art lacks an electromagnetic shielding and anti-corrosion integrated functional film with a compact structure, firm interface bonding and scalable preparation, resulting in insufficient long-term reliability of metal substrates in complex environments. Therefore, an electromagnetic shielding and anti-corrosion integrated functional film for metal substrates and a preparation method thereof are proposed.
[0005] To achieve the above-mentioned object, the present invention adopts the following technical solution: an electromagnetic shielding and anti-corrosion integrated functional film for a metal substrate and a preparation method thereof, comprising a film body, the film body consisting of a bottom layer, an electromagnetic shielding layer, and an anti-corrosion layer, the electromagnetic shielding layer covering the top of the bottom layer, and the anti-corrosion layer covering the top of the electromagnetic shielding layer, wherein:
[0006] The bottom layer is a composite layer formed by nano-zirconia / graphene with a thickness of 10-50nm. A dense zirconia network is formed on the surface of the metal substrate through the sol-gel method, and graphene is evenly dispersed in it to enhance the interface bonding strength;
[0007] The electromagnetic shielding layer is a MXene two-dimensional material / silver nanowire gradient structure with a thickness of 50-200nm. The MXene nanosheets are vertically arranged to form conductive channels, and the silver nanowires are interspersed to form a three-dimensional conductive network.
[0008] The anti-corrosion layer is a polytetrafluoroethylene / silica hybrid coating with a thickness of 200-500nm. A super-hydrophobic structure (contact angle ≥ 150°) is formed on the surface of the shielding layer through plasma polymerization technology, and silica nanoparticles are evenly embedded in the PTFE matrix to enhance mechanical strength.
[0009] Furthermore, in the MXene / silver nanowire gradient structure, the lateral size of the MXene nanosheets is 1-5 μm, the diameter of the silver nanowires is 50-200 nm, and the mass ratio of the two is (3:1)-(5:1).
[0010] Furthermore, in the polytetrafluoroethylene / silicon dioxide hybrid coating, the particle size of the silicon dioxide nanoparticles is 20-50 nm, accounting for 10% to 20% of the total mass of the coating, and the coating surface is modified by fluoroalkyl silane to form a low surface energy interface.
[0011] A method for preparing a functional film comprises the following steps:
[0012] S1. Preparation of bottom layer: immersing the metal substrate in an ethanol solution containing 0.1-0.5 mol / L zirconium oxychloride and 0.01-0.05 mol / L graphene dispersion, spin coating at 60-80°C to form a film, and then calcining at 300-400°C for 2-4 hours to form a nano zirconium oxide / graphene composite layer;
[0013] S2. Preparation of electromagnetic shielding layer: MXene target and silver target are alternately deposited on the bottom surface by magnetron sputtering method, wherein the MXene sputtering power is 100-200W, the silver sputtering power is 50-100W, and the deposition rate is 0.1-0.5nm / s to form a gradient structure;
[0014] S3. Preparation of anti-corrosion layer: Place the shielding layer sample in a plasma reactor, introduce a mixed gas of tetrafluoroethylene monomer and ethyl orthosilicate (volume ratio 1:1), and polymerize it at a radio frequency power of 100-200W for 10-30 minutes to form a polytetrafluoroethylene / silicon dioxide hybrid coating.
[0015] Furthermore, the graphene dispersion in step 1 is prepared by ultrasonic exfoliation, the graphene concentration is 0.5-1.0 mg / mL, and 0.1-0.3 wt % of 3-aminopropyltriethoxysilane is added to the solution as a coupling agent.
[0016] Furthermore, the magnetron sputtering process in step 2 is carried out in an argon atmosphere (purity ≥ 99.999%), with a gas pressure of 0.5-1.0 Pa and a substrate temperature controlled at 50-80°C.
[0017] Furthermore, the plasma polymerization process in step 3 further comprises spraying 0.1-0.5 wt % fluoroalkylsilane ethanol solution on the coating surface, and curing at 80-100° C. for 1-2 hours after spraying.
[0018] Compared with the prior art, the advantages and positive effects of the present invention are:
[0019] (1) The nano-zirconia / graphene bottom layer is tightly bonded to the metal substrate through chemical bonding (Si-O-Zr bond). At the same time, the two-dimensional structure of graphene can inhibit the penetration of corrosive media and improve the interface adhesion (pulling strength ≥ 50MPa);
[0020] (2) MXene is vertically arranged to form an efficient carrier transmission channel, and silver nanowires are interspersed in it to form a three-dimensional conductive network, which enables the shielding layer to achieve a multi-level attenuation mechanism of "reflection-absorption-re-reflection" in the high-frequency band, and the shielding effectiveness is improved compared with a single MXene coating;
[0021] (3) The polytetrafluoroethylene / silica hybrid coating forms a dense structure through plasma polymerization, combined with fluoroalkyl silane modification, so that the surface contact angle is ≥150°, effectively preventing water and oxygen corrosion, and the surface impedance change rate after salt spray test is ≤5%; both the sol-gel method and plasma polymerization are carried out at low temperature, the energy consumption is lower than that of traditional electroplating processes, and there is no heavy metal pollution. In summary, the functional membrane in this application has higher reliability and practicality than the functional membrane in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 It is a schematic diagram of a partial cross-sectional three-dimensional structure of the membrane body of the present invention;
[0023] Figure 2 This is a flowchart of the method for preparing the functional membrane of the present invention.
[0024] Legend: 1. Membrane body; 2. Bottom layer; 3. Electromagnetic shielding layer; 4. Anti-corrosion layer. DETAILED DESCRIPTION
[0025] Example 1, as Figure 1-2As shown, the electromagnetic shielding and anti-corrosion integrated functional film for metal substrates includes a film body 1, which is characterized in that: the film body 1 is composed of a bottom layer 2, an electromagnetic shielding layer 3 and an anti-corrosion layer 4, the electromagnetic shielding layer 3 is covered on the top of the bottom layer 2, and the anti-corrosion layer 4 is covered on the top of the electromagnetic shielding layer 3, wherein: the bottom layer 2 is a composite layer formed by nano-zirconium oxide / graphene with a thickness of 10-50nm, and a dense zirconium oxide network is formed on the surface of the metal substrate by a sol-gel method, and graphene is uniformly dispersed therein to enhance the interface bonding force; the electromagnetic shielding layer 3 is a MXene two-dimensional material / silver nanowire gradient structure with a thickness of 10-50nm. The thickness of the shielding layer is 50-200nm, in which MXene nanosheets are arranged vertically to form conductive channels, and silver nanowires are interspersed to form a three-dimensional conductive network; the anti-corrosion layer 4 is a polytetrafluoroethylene / silicon dioxide hybrid coating with a thickness of 200-500nm. A super-hydrophobic structure (contact angle ≥ 150°) is formed on the surface of the shielding layer through plasma polymerization technology, and silicon dioxide nanoparticles are evenly embedded in the PTFE matrix to enhance mechanical strength. The nanoporous structure of zirconium oxide (10-50nm) is formed into a dense barrier through the sol-gel method, which can reduce the corrosion current density of the metal substrate to 10 -7 A / cm 2 Below. Two-dimensional graphene sheets (lateral size 1-5μm) are interspersed in the zirconia network, forming chemical bonds (Si-O-Zr bonds) with the metal surface through π-π stacking, which increases the interfacial adhesion to over 50MPa. MXene nanosheets are vertically arranged to form "conductive channels", and silver nanowires (diameter 50-200nm) are interspersed to form a three-dimensional network. A multi-level attenuation mechanism gradient design (MXene content decreases from the bottom layer to the surface) is implemented in the 1-18GHz frequency band, making the current density distribution more uniform and avoiding local overheating problems. The PTFE / SiO2 composite layer (contact angle ≥150°) formed by plasma polymerization can extend the water contact time to roll off within 0.1 seconds. After 1000 hours of salt spray testing, the corrosion rate is ≤0.01mm / a. The addition of silica nanoparticles (20-50nm) increases the coating hardness from 2H to 4H, and the wear resistance exceeds 100,000 times, making it suitable for high-friction scenarios and improving the functionality of the functional membrane.
[0026] Reference Figure 1-2As shown in this embodiment, the MXene / silver nanowire gradient structure has a lateral size of 1-5μm for the MXene nanosheets and a diameter of 50-200nm for the silver nanowires, with a mass ratio of (3:1) to (5:1). When the MXene content is too high (5:1), the silver nanowire network is squeezed, resulting in a decrease in shielding effectiveness at high frequencies (such as 28GHz for 5G). If the silver content is too high (<3:1), the vertically aligned MXene structure is destroyed, reducing reflection loss at low frequencies (1-3GHz). At the optimal ratio (4:1), the composite material achieves an average shielding effectiveness of 52dB from 1-18GHz while maintaining a low surface impedance of 0.5Ω / sq.
[0027] Reference Figure 1-2 As shown in this embodiment, the silica nanoparticles in the polytetrafluoroethylene / silica hybrid coating have a particle size of 20-50 nm and constitute 10% to 20% of the total coating mass. The coating surface is modified with fluoroalkylsilane to form a low-surface-energy interface. This nanoparticle-filling effect optimizes the mechanical properties of the PTFE substrate. A coating with a content of less than 10% exhibits insufficient hardness, while a content of 20% leads to increased brittleness. Experiments show that a coating with a 15% content remains crack-free after 1,000 bending cycles, while its surface energy decreases from 40 mN / m to 12 mN / m, significantly improving its hydrophobicity.
[0028] Reference Figure 1-2 As shown, a method for preparing a functional film comprises the following steps:
[0029] S1. Preparation of the bottom layer: Immerse the metal substrate in an ethanol solution containing 0.1-0.5 mol / L zirconium oxychloride and 0.01-0.05 mol / L graphene dispersion, spin-coat at 60-80°C to form a film, and then calcine at 300-400°C for 2-4 hours to form a nano-zirconium oxide / graphene composite layer; the 60-80°C spin-coating + 300-400°C calcination process reduces energy consumption by 60% compared to traditional electroplating (800°C) and avoids heavy metal pollution. 3-Aminopropyltriethoxysilane (0.1-0.3wt%) is added to the graphene dispersion to achieve chemical bonding between graphene and zirconium oxide through Si-O-Zr bonds, and the interfacial bonding strength is increased to 45MPa;
[0030] S2. Preparation of electromagnetic shielding layer: MXene target and silver target are alternately deposited on the bottom surface by magnetron sputtering method, wherein the MXene sputtering power is 100-200W, the silver sputtering power is 50-100W, and the deposition rate is 0.1-0.5nm / s to form a gradient structure; argon atmosphere (purity ≥99.999%) and substrate temperature control of 50-80℃ can avoid MXene oxidation (Ti3 + →Ti4 +) to ensure stable conductive performance. Gradient deposition (MXene sputtering power 100-200W, silver 50-100W) achieves a coating density of 98% and a porosity of <2%, a 50% improvement over traditional evaporation processes;
[0031] S3. Preparation of the Anticorrosion Layer: The shielding layer sample is placed in a plasma reactor and introduced with a mixture of tetrafluoroethylene monomer and tetraethyl orthosilicate (1:1 by volume). Polymerization is carried out at a radio frequency power of 100-200W for 10-30 minutes to form a polytetrafluoroethylene / silica hybrid coating. Under a radio frequency power of 100-200W, the mixture of tetrafluoroethylene and tetraethyl orthosilicate (1:1 by volume) forms a uniform coating within 30 minutes, with a deposition rate of 0.5nm / s, which is 10 times more efficient than traditional spray coating. This process does not require solvents.
[0032] Reference Figure 1-2 As shown, in this embodiment: the graphene dispersion in step 1 is prepared by ultrasonic exfoliation, the graphene concentration is 0.5-1.0 mg / mL, and 0.1-0.3 wt% of 3-aminopropyltriethoxysilane is added to the solution as a coupling agent, and the magnetron sputtering process in step 2 is carried out in an argon atmosphere (purity ≥99.999%), the gas pressure is 0.5-1.0 Pa, and the substrate temperature is controlled at 50-80°C. The particle energy and deposition rate are balanced by setting this gas pressure range: too low gas pressure (<0.5 Pa) leads to excessive particle energy, destroying the MXene structure; too high gas pressure (1.0 Pa) reduces the deposition rate. Experiments show that the coating achieves its highest density at 0.8 Pa, improving shielding effectiveness by 12%. A reasonable temperature range also prevents cracking during sputtering. The plasma polymerization process described in step 3 also involves spraying a 0.1-0.5wt% fluoroalkylsilane ethanol solution on the coating surface, followed by curing at 80-100°C for 1-2 hours. This concentration range was optimized through contact angle testing: too low a concentration (<0.1wt%) prevented the formation of a complete hydrophobic layer; too high a concentration (0.5wt%) resulted in excessive surface roughness. At the optimal concentration (0.3wt%), the coating's surface energy dropped to 6mN / m, and it maintained superhydrophobic properties after 100 cycles of temperature cycling from -40°C to 150°C.
[0033] Working principle: When preparing the functional membrane, the metal substrate is immersed in an ethanol solution containing 0.1-0.5 mol / L zirconium oxychloride and 0.01-0.05 mol / L graphene dispersion, and spin-coated at 60-80°C to form a film, which is then calcined at 300-400°C for 2-4 hours to form a nano-zirconium oxide / graphene composite layer. Subsequently, a magnetron sputtering method is used to alternately deposit MXene targets and silver targets on the surface of the bottom layer 2, wherein the MXene sputtering power is 100-200W, the silver sputtering power is 50-100W, and the deposition rate is 0.1-0.5nm / s to form a gradient structure. Finally, the shielding layer sample is placed in a plasma reactor, and a mixed gas of tetrafluoroethylene monomer and ethyl orthosilicate (volume ratio 1:1) is introduced. It is polymerized at a radio frequency power of 100-200W for 10-30 minutes to form a polytetrafluoroethylene / silicon dioxide hybrid coating, completing the preparation of the membrane body 1.
[0034] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification of the above embodiment based on the technical essence of the present invention that does not deviate from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
Claims
1. Electromagnetic shielding and anti-corrosion integrated functional film for metal substrates, characterized by: The invention comprises a membrane body (1), wherein the membrane body (1) is composed of a bottom layer (2), an electromagnetic shielding layer (3) and an anti-corrosion layer (4), wherein the electromagnetic shielding layer (3) covers the top of the bottom layer (2), and the anti-corrosion layer (4) covers the top of the electromagnetic shielding layer (3).
2. The integrated electromagnetic shielding and anti-corrosion functional film for a metal substrate according to claim 1, characterized in that: in: The bottom layer (2) is a composite layer formed of nano-zirconia / graphene with a thickness of 10-50 nm. A dense zirconia network is formed on the surface of the metal substrate by a sol-gel method, and graphene is uniformly dispersed therein to enhance the interface bonding force.
3. The integrated electromagnetic shielding and anti-corrosion functional film for a metal substrate according to claim 2, characterized in that: in: The electromagnetic shielding layer (3) is a MXene two-dimensional material / silver nanowire gradient structure with a thickness of 50-200 nm, wherein the MXene nanosheets are vertically arranged to form a conductive channel, and the silver nanowires are interspersed therein to form a three-dimensional conductive network; The anti-corrosion layer (4) is a polytetrafluoroethylene / silicon dioxide hybrid coating with a thickness of 200-500 nm. A super hydrophobic structure (contact angle ≥ 150°) is formed on the surface of the shielding layer through plasma polymerization technology, and silicon dioxide nanoparticles are uniformly embedded in the PTFE matrix to enhance mechanical strength.
4. The integrated electromagnetic shielding and anti-corrosion functional film for a metal substrate according to claim 1, characterized in that: In the MXene / silver nanowire gradient structure, the lateral size of the MXene nanosheet is 1-5 μm, the diameter of the silver nanowire is 50-200 nm, and the mass ratio of the two is (3:1)-(5:1).
5. The integrated electromagnetic shielding and anti-corrosion functional film for a metal substrate according to claim 4, characterized in that: In the polytetrafluoroethylene / silicon dioxide hybrid coating, the particle size of silicon dioxide nanoparticles is 20-50 nm, accounting for 10% to 20% of the total mass of the coating, and the coating surface is modified by fluoroalkyl silane to form a low surface energy interface.
6. A method for preparing an integrated electromagnetic shielding and anti-corrosion functional film for a metal substrate, characterized by: The method of using the electromagnetic shielding and anti-corrosion integrated functional film for a metal substrate according to any one of claims 1 to 5 comprises the following steps: S1. Preparation of bottom layer: immersing the metal substrate in an ethanol solution containing 0.1-0.5 mol / L zirconium oxychloride and 0.01-0.05 mol / L graphene dispersion, spin coating at 60-80°C to form a film, and then calcining at 300-400°C for 2-4 hours to form a nano zirconium oxide / graphene composite layer; S2. Preparation of electromagnetic shielding layer: MXene target and silver target are alternately deposited on the bottom surface by magnetron sputtering method, wherein the MXene sputtering power is 100-200W, the silver sputtering power is 50-100W, and the deposition rate is 0.1-0.5nm / s to form a gradient structure; S3. Preparation of anti-corrosion layer: Place the shielding layer sample in a plasma reactor, introduce a mixed gas of tetrafluoroethylene monomer and ethyl orthosilicate (volume ratio 1:1), and polymerize it at a radio frequency power of 100-200W for 10-30 minutes to form a polytetrafluoroethylene / silicon dioxide hybrid coating.
7. The method for preparing an integrated electromagnetic shielding and anti-corrosion functional film for a metal substrate according to claim 6, characterized in that: The graphene dispersion described in step 1 is prepared by ultrasonic exfoliation.
8. The method for preparing an integrated electromagnetic shielding and anti-corrosion functional film for a metal substrate according to claim 7, characterized in that: The graphene concentration is 0.5-1.0 mg / mL, and 0.1-0.3 wt % of 3-aminopropyltriethoxysilane is added to the solution as a coupling agent.
9. The method for preparing an integrated electromagnetic shielding and anti-corrosion functional film for a metal substrate according to claim 8, characterized in that: The magnetron sputtering process in step 2 is carried out in an argon atmosphere (purity ≥ 99.999%), with a gas pressure of 0.5-1.0 Pa and a substrate temperature controlled at 50-80°C.
10. The method for preparing an integrated electromagnetic shielding and anti-corrosion functional film for a metal substrate according to claim 9, characterized in that: The plasma polymerization process in step 3 further includes spraying 0.1-0.5 wt % fluoroalkylsilane ethanol solution on the coating surface, and curing at 80-100° C. for 1-2 hours after spraying.