Preparation method of flexible high-temperature-resistant magnetic shielding film and film

Abstract

The application belongs to the technical field of low-noise magnetic shielding and specifically relates to a flexible high-temperature-resistant magnetic shielding film preparation method and the film, which comprises the following steps: pasting PI double-sided adhesive tape on one side of a glass slide and pasting a PTFE / PDMS film thereon as a substrate for silver nanowire net spraying; configuring silver nanowire solution and adopting a spray gun to spray the silver nanowire solution on the PTFE / PDMS film to obtain a silver nanowire net; spin-coating, curing and transferring the silver nanowire net to obtain a flexible substrate of the cured silver nanowire net; and magnetron sputtering FeCoNiZr0.4 medium-entropy alloy film on the flexible substrate to obtain the flexible high-temperature-resistant magnetic shielding film. The application utilizes the electromagnetic shielding performance of the silver nanowire net, sputters soft magnetic films on both sides of the silver nanowire net, further improves the shielding efficiency of the traditional single-layer shielding film, and obtains a lightweight film that meets the flexible application requirements of the magnetic shielding film and has a complex application space. The flexible shielding film is light in weight, good in flexibility and excellent in shielding performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of low-noise magnetic shielding, and in particular relates to a preparation method of a flexible high-temperature resistant magnetic shielding film and the film. Background Art

[0002] In recent years, the application of electronic equipment in various research fields, such as industry, medicine, and communications, has brought numerous benefits to human development. However, this has also led to an increasing number of electromagnetic interference sources, making the local geomagnetic field increasingly complex. Applications such as material structure analysis, mineral exploration, and biomagnetic field measurement are increasingly demanding of the external magnetic field. Some sophisticated electrical and electronic equipment cannot function properly in the presence of interfering magnetic fields, making magnetic shielding technology essential to eliminate or reduce external interfering magnetic fields.

[0003] CN116867255A discloses a magnetic shielding device with low magnetic noise and high shielding performance based on Permalloy-ferrite-superconducting coils. The shielding device uses a multi-layer structure for material splicing. Permalloy and ferrite do not have flexible characteristics, so there are problems such as difficulty in splicing, many pores, and heavy weight. CN116033731A discloses an electromagnetic silver paste shielding film and its preparation process. By improving the insulating layer raw materials and the ratio of each raw material, as well as the adhesive coating process, the bending resistance, wear resistance, and high reflective performance of the electromagnetic shielding film are improved. However, the shielding effectiveness of the silver paste is limited and the shielding effect is poor. The 5-layer film structure has limited bendability, making it difficult to use in precision measuring instruments and equipment that require high-performance magnetic shielding. CN112080050B discloses a flexible magnetic shielding material and its preparation method. By limiting the mixing order of magnetic powder, binder, and auxiliary materials in the preparation process, the magnetic permeability and saturation magnetization intensity of the flexible magnetic shielding sheet are improved. However, the magnetic permeability of a flexible magnetic sheet in good condition is only 46.3, which makes it difficult to use in the field of high-precision magnetic noise shielding.

[0004] In summary, traditional shielding materials using an outer layer of Permalloy can effectively shield against the Earth's magnetic field due to their excellent magnetic shielding properties. However, on the one hand, block materials are large in size and density, resulting in high cost. The gaps and welding between block materials change the properties of the material at the joints, which reduces the magnetic shielding effectiveness. On the other hand, due to the increasing shortcomings of device miniaturization and integration, traditional sheet materials can no longer meet the demand for flexible and portable magnetic shielding materials. Summary of the Invention

[0005] The present invention aims to overcome the shortcomings of the prior art and provides a method for preparing a three-layer magnetic shielding film that combines a flexible nano-silver mesh electromagnetic shielding film with an FeCoNiZr soft magnetic film. By magnetron sputtering the film with elements such as Fe, Co, Ni, and Zr, the flexible nano-silver mesh is fully utilized, with its inherent high electrical conductivity, good air stability, high temperature stability, and high shielding effectiveness. Furthermore, the material has low roughness and strong bonding with the magnetic shielding film. This material can better meet the application requirements of lightweight, highly enclosed, miniaturized, and flexible wearable weak magnetic shielding.

[0006] The complete technical solution of the present invention includes:

[0007] A method for preparing a flexible high-temperature resistant magnetic shielding film comprises the following steps:

[0008] Step (1) Substrate preparation: Select a glass slide, stick PI double-sided tape on one side of the glass slide, stick a layer of PTFE / PDMS film on the double-sided tape as the substrate for silver nanobeam spraying, cut off a part of the substrate around the periphery and expose the glass slide;

[0009] Step (2) preparing the silver nanowire solution: weighing a solvent and the first silver nanowire solution and mixing them to obtain a second silver nanowire solution;

[0010] Step (3) spraying the silver nanobeam network: using a spray gun, spraying the second nanosilver wire solution on the PTFE / PDMS film to obtain the silver nanobeam network;

[0011] Step (4) spin coating, curing, and transferring the silver nanobeam network: spin coating the silver nanobeam network with a polyimide solution in a coating machine, then drying and curing the silver nanobeam network and transferring the solution to an adhesive tape to obtain a flexible substrate with a cured silver nanobeam network;

[0012] Step (5) magnetron sputtering a FeCoNiZr medium-entropy alloy film on a flexible substrate: placing the flexible substrate with the solidified silver nanobeam network on a magnetron sputtering sample disk, and sputtering a first medium-entropy alloy film and a second medium-entropy alloy film on both sides of the flexible substrate, respectively, to obtain a flexible high-temperature resistant magnetic shielding film.

[0013] Furthermore, in step (1), the size of the slide is 2.5 cm × 2.5 cm.

[0014] Furthermore, in step (2), the solvent is anhydrous methanol, and the concentration of the second nanosilver wire solution is 0.4 mg / ml to 0.7 mg / ml.

[0015] Furthermore, in step (3), the spray gun is connected to a high-purity nitrogen source to control the argon pressure, spray gun spray speed and spray gun distance during the spraying process.

[0016] Furthermore, the argon pressure is 0.1-0.3 MPa, the spray gun speed is 0.1-0.3 ml / min, and the spray gun distance is 10-15 cm.

[0017] Furthermore, in step (4), the speed of the glue spreader is 700-1000 r / min, and the time is 80s-120s.

[0018] Furthermore, in step (4), the curing process is specifically as follows: the spin-coated substrate is placed in a drying oven for the first curing. After the curing is completed, the PI film embedded with the silver nanobeam network is removed, the silver nanobeam network side is facing outward, and the PI film is fixed on a glass slide with a high-temperature tape for the second curing. After the curing is completed, the high-temperature tape is removed and fixed with a new high-temperature tape for the third curing.

[0019] Furthermore, the first curing temperature is 80°C~100°C, and the time is 1 hour; the second curing temperature is 140°C~160°C, and the time is 40 minutes; the third curing temperature is 180°C~240°C, and the time is 1 hour.

[0020] Furthermore, in step (4), the spacing of the solidified silver nanobeam network is 8-13 μm, and the beam width is 1-2 μm.

[0021] Furthermore, the component contents of the first FeCoNiZr mesenteroy alloy film and the second FeCoNiZr mesenteroy alloy film are determined by a high-throughput screening composition design method.

[0022] Furthermore, the high-throughput screening component design method is as follows: first, the preset range of the content of each component element is determined, and high-purity Fe, high-purity Co, high-purity Ni, and high-purity Zr targets are used and placed in a magnetron sputtering chamber. A sample holder is placed between the four targets, and multiple high-resistivity non-magnetic material substrates are placed on the sample holder. Each target uses an independent target gun, and magnetron sputtering is used to sputter-coat the substrate surface to obtain multiple thin film samples with component content gradients;

[0023] Subsequently, the desorption rate of each element at different sputtering powers is obtained through experiments. Based on the desorption rate of each element at different sputtering powers and the preset range of the content of each component element, the sputtering power of each target material and the placement parameters of the thin film samples are determined so that the component content of multiple thin film samples meets the preset range of the content of each component element;

[0024] The sputtering power of each target is determined by determining the sputtering power of the Fe target and the desorption rate of Fe at this power, and then selecting the corresponding power for other components so that their desorption rates at the corresponding sputtering power meet the following conditions:

[0025]

[0026] Where: For components The desorption rate at the selected corresponding power is, is the desorption rate of Fe component at the reference sputtering power, For components The minimum atomic percentage content, For components The maximum atomic percentage content of is the minimum atomic percentage content of Fe, is the maximum atomic percentage content of Fe.

[0027] The obtained multiple film samples were tested, and the component content of the medium-entropy alloy target was screened according to the saturation magnetization intensity, coercive force, and resistivity performance requirements.

[0028] Furthermore, the component content of the medium-entropy alloy target material screened out is specifically: Fe:Co:Ni:Zr=1:1:1:0.4, and the above is the atomic ratio.

[0029] Furthermore, a flexible high-temperature resistant magnetic shielding film is prepared using the method.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) Lightweight and flexible, it meets the application requirements of magnetic shielding films, and its application space is complex and varied: Flexible shielding films are lightweight, flexible, and have excellent shielding performance. Not only can they be used in large shielding chambers, but also, due to their excellent flexibility, they can meet the requirements of complex and varied shielding spaces.

[0032] (2) Three-layer structure design to enhance shielding effect: A three-layer structure of soft magnetic film / flexible film / soft magnetic film is adopted, and the flexible substrate of the cured silver nanobeam network has the characteristics of electromagnetic shielding performance. At the same time, soft magnetic film is sputtered on both sides of the flexible substrate to further improve the shielding effectiveness of the traditional single-layer shielding film. Experimental data shows that the film has excellent shielding performance and is suitable for weak magnetic shielding scenarios.

[0033] (3) Small gaps in the joints, low processing difficulty, and good shielding effect: Compared with traditional Permalloy, it does not require additional heat treatment and does not have the characteristics of high processing equipment requirements and high difficulty. At the same time, it is light in weight and simple to process. It can be cut according to needs. The gaps at the joints are small and no welding is required. The film performance is stable and the shielding effect is good.

[0034] (4) Stable properties and excellent temperature stability: The film layer has the advantages of corrosion resistance, stable performance, high air stability, and strong bonding strength. The prepared flexible shielding film can maintain stable performance below 250°C without reducing the soft magnetic properties. It can better cope with the temperature increase caused by the heat generated by the application environment of magnetic shielding films and has a wide range of application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the structure of the magnetic shielding film of the present invention.

[0036] Figure 2 The topography of the substrate with silver nanobeam network.

[0037] Figure 3 Schematic diagram of the cross section of the silver nanobeam network.

[0038] In the figure, 1 is a flexible substrate of a solidified silver nanobeam network, 2 is a first medium-entropy alloy film, and 3 is a second medium-entropy alloy film. DETAILED DESCRIPTION

[0039] The present invention is described in detail below with reference to the embodiments and accompanying drawings. However, it should be understood that the embodiments and accompanying drawings are merely exemplary descriptions of the present invention and do not constitute any limitation on the scope of protection of the present invention. All reasonable variations and combinations within the scope of the inventive concept of the present invention fall within the scope of protection of the present invention.

[0040] Compared to traditional unitary and binary alloys, medium-entropy alloys exhibit greater mixing entropy and lattice distortion, increasing the scattering of metallic conductive phonons and significantly increasing the material's resistivity. Soft magnetic medium-entropy alloy films (HEATFs) exhibit superior resistivity compared to other soft magnetic films, along with excellent magnetic properties, high thermal stability, corrosion resistance, and robust mechanical properties. They also exhibit good adhesion to substrates, making them promising films for diverse applications.

[0041] In order to obtain high-performance soft magnetic medium-entropy alloys and to obtain high-quality soft magnetic films, the present invention designs the component types of medium-entropy alloys. The elements selected as alloy components are Zr, Fe, Co, and Ni atoms. Due to their similar sizes, they tend to form simple cubic and body-centered cubic structures, which are called base elements. Among them, Fe has the characteristics of high magnetic moment and high Curie temperature, and low magnetocrystalline anisotropy. Co has a medium magnetic moment, and FeCo alloys have higher saturation magnetization than pure Fe and pure Co, and have a high Curie temperature. However, FeCo alloys have a positive magnetostriction coefficient λs, which will result in a larger coercive force. Ni has the lowest magnetic moment, and the saturation magnetic induction intensity of pure Ni is very low, with a negative magnetostriction coefficient. Adding Ni can neutralize the magnetostriction coefficient of FeCo alloy, and can have high magnetic permeability and lower coercive force. The mixing enthalpy between Zr and Fe, Co, and Ni elements is very low. The addition of Zr is beneficial to the formation of amorphous structure in the multi-principal element alloy system, thereby eliminating the influence of grain boundaries on magnetic properties; enhancing the scattering effect on free electrons, thereby increasing the resistivity of the film and further optimizing the soft magnetic properties.

[0042] In the present invention, the optimal components of the medium-entropy alloy are determined by a high-throughput screening composition design method. In order to illustrate the alloy component optimization process of the present invention, the high-throughput screening method adopted is further described.

[0043] (1) Multi-component gradient thin film sputtering: Using the magnetron sputtering process, the chamber atmosphere conditions are controlled, and the various component elements of the high entropy alloy target are deposited on the surface of each substrate by magnetron sputtering to obtain multiple thin film samples with different component contents. Specifically including:

[0044] First, the preset range of the content of each component element is determined as: Zr: 10.2~15.3at%, Fe: 20.7~46.2at%, Co: 15.7~51.1at%, Ni: 14.5~33.6at%.

[0045] To ensure that the component content of the thin film samples is within a preset range and that the content of each component in each sample varies as evenly as possible, facilitating subsequent high-throughput screening, the present invention analyzes the spatial distribution of atoms from each target after detachment (the concentration of target element atoms in space decreases as the distance from the target increases) based on the different atomic binding forces of each target during sputtering. The main influencing factors (the total number of samples, the horizontal and vertical spacing of each sample) were analyzed, and the following experimental method was selected:

[0046] High-purity Fe, high-purity Co, high-purity Ni, and high-purity Zr targets are used and evenly placed at four positions in the chamber. The angles of the four target positions are adjusted so that they form a 45° angle with the horizontal. The sample holder is placed in the middle of the four targets, and multiple high-resistivity non-magnetic material substrates are placed on the sample holder.

[0047] Firstly, fixed sputtering time t0 and the same sample with fixed distance d0 of target material are selected, and the deposition thickness of each target element on the sample surface under different power is measured to characterize the desorption speed under different power. Then, taking Fe component as the reference, the reference sputtering power (250 W) of Fe target and the desorption speed of Fe under this power are determined, and then the corresponding power is selected for other components to make the desorption speed under the corresponding sputtering power meet:

[0048]

[0049] In the formula: is the component the desorption speed under the selected corresponding power, is the desorption speed of Fe component under the reference sputtering power, is the component the minimum atomic percentage content in the preset range, is the component the maximum atomic percentage content in the preset range, is the minimum atomic percentage content of Fe in the preset range, is the maximum atomic percentage content of Fe in the preset range.

[0050] Then the placement parameters (horizontal distance, vertical distance and number) of the sample are determined. Fe target and Zr target are selected, and the deposition rate (the ratio of deposition thickness to deposition time) of the sample closest to the target and the deposition rate of the sample farthest from the target are measured under different sample distances (horizontal distance, vertical distance) and sample numbers, and the attenuation degree is counted. The relationship between the attenuation degree and the sample horizontal distance, vertical distance and sample number is obtained by multiple linear regression. According to the obtained relationship, the corresponding sample distance and number are selected to make:

[0051]

[0052]

[0053] In the formula, is the maximum value of the atomic percentage content ratio of Fe component to Zr component in the preset range in high-throughput test, is the maximum value of the atomic percentage content ratio of Zr component to Fe component in the preset range in high-throughput test. is the deposition rate of Fe atoms on the sample closest to the Fe target, is the deposition rate of Fe atoms on the sample farthest from the Fe target; is the deposition rate of Zr atoms on the sample closest to the Zr target, is the deposition rate of Zr atoms on the sample farthest from the Zr target.

[0054] (2) Sample testing and target component design: The obtained multiple thin film samples were tested. According to the performance requirements of saturation magnetization, coercive force, and resistivity, the component content of the medium-entropy alloy was screened and converted into an atomic ratio of Fe:Co:Ni:Zr=1:1:1:0.4.

[0055] According to the determined component content of the medium-entropy alloy, corresponding raw materials are selected for target preparation.

[0056] After the target material is prepared, it is cut and then heat treated. In terms of the target cutting size and heat treatment process, a response surface model is constructed for experimental design, and the optimized parameter combination is obtained based on the experimental results. The selected controllable variables include: target cutting thickness X1, with a value range of 10~20mm; target cutting diameter X2, with a value range of 100~150mm; number of heat treatments X3, with a value range of 1~3 times; heat treatment temperature X4, with a value range of 700~1000℃; heat treatment time X5, with a value range of 1~15 hours.

[0057] The degree of deviation of component content Y is selected as the response variable. Factor level coding is performed, and actual experimental parameters are constructed according to the coded values ​​of each designed experiment. Designs that do not meet actual requirements are removed, and a central composite experimental design is performed. Multiple groups of experiments are conducted, and the degree of deviation of component content Y in each group of experiments is measured and calculated. A second-order polynomial regression model based on the degree of deviation of component content and controllable variables is established, and the coefficient estimate of the regression model is obtained by fitting using the least squares method. The predicted degree of deviation of component content Y obtained by the regression model is used as the objective function, and the goal is to minimize Y. The initial solution is set and iterative optimization is performed. When the set maximum number of iterations is reached, the current solution at this time is the optimized parameter combination. Specifically, the target cutting diameter processing size is 142mm, the cutting thickness is preferably 16mm, and a two-stage heat treatment process is adopted, wherein the first-stage heat treatment temperature is 820℃, and the heat treatment holding time is 10h; the second-stage heat treatment temperature is 980℃, and the heat treatment holding time is 1.5h.

[0058] After the target material is heat-treated, magnetron sputtering is used to prepare a flexible, high-temperature resistant magnetic shielding film. Specifically, a three-layer magnetic shielding film is a combination of a flexible nano-silver mesh electromagnetic shielding film and a FeCoNiZr soft magnetic film. The main steps of the preparation method include:

[0059] S1. Substrate preparation:

[0060] Cut a 7.5×2.5cm glass slide into 2.5×2.5cm slides (providing a flat, temperature-resistant base for the PTFE / PDMS film), stick PI high-temperature-resistant double-sided tape on one side of the slide (to fix the PTFE / PDMS film), and then stick a layer of PTFE / PDMS film on the PI high-temperature-resistant double-sided tape (PDMS is more flat and smooth) as the base for spraying the silver nanobeam network. Use a knife to cut about 2mm around the base to expose the glass slide (taking advantage of the hydrophilicity of the glass slide to prevent the PI solution from agglomerating and causing an uneven base during spin coating).

[0061] S2. Silver nanowire solution preparation:

[0062] Use a measuring cylinder to weigh the solvent (anhydrous methanol or anhydrous ethanol) into a brown bottle, then use a plastic dropper to weigh the nanosilver wire solution into the brown bottle, shake well, and prepare the nanosilver wire solution.

[0063] S3. Silver nanobeam mesh spraying:

[0064] Open a fume hood, connect a manual spray gun to high-purity nitrogen, adjust the air valve pressure, spray gun speed, and spray gun distance, and spray the silver wire solution onto one side of the PTFE / PDMS film. Utilizing the coffee ring effect, a silver nanobeam network can be formed. The micromorphology of the sprayed silver nanobeam network is observed using a metallographic microscope, and the square resistance of the silver nanobeam network is measured using a four-probe tester.

[0065] S4. Silver nanobeam network spin coating, curing, and transfer:

[0066] Place the substrate with the silver nanobeam network after spraying on a coater, turn on the vacuum pump, fix one side of the glass slide on the coater, then drop-coat the polyimide (PI) solution on one side of the silver nanobeam network, adjust the coater speed for spin coating, place the spin-coated substrate in a drying oven, and cure it three times. After the first curing is completed, use tweezers to remove the resulting PI film embedded with the silver nanobeam network, turn the silver nanobeam network side outward, and use high-temperature tape to fix the PI film on the glass slide for the second curing. After the completion, remove the high-temperature tape (to reduce the internal stress caused by high temperature), and fix it again with high-temperature tape for the third curing. Its surface morphology and cross-sectional structure are shown in Figure 2. Figure 2 and Figure 3 shown.

[0067] S5. Magnetron sputtering of FeCoNiZr0.4 medium entropy alloy thin films on flexible substrates:

[0068] The obtained flexible substrate 1 with the solidified silver nanobeam network is attached to a magnetron sputtering sample plate, and the first medium entropy alloy film 2 and the second medium entropy alloy film 3 are sputtered on both sides of the substrate using the aforementioned heat-treated target material to obtain a three-layer flexible magnetic shielding film, such as Figure 1 shown.

[0069] Preferably, in the PTFE / PDMS film in step S1, the flexible substrate prepared by PDMS is smoother and has lower roughness.

[0070] Preferably, the concentration of the silver nanowire solution in step S2 is 0.4 mg / ml to 0.7 mg / ml, and anhydrous methanol is selected as the solvent because it evaporates faster and has a better silver nanowire network ringing effect.

[0071] Preferably, in step S3, the air valve pressure is 0.1-0.3 MPa, the spray gun speed is 0.1-0.3 ml / min, the spray gun distance is 10-15 cm, the silver nanobeam network square resistance is 10-15 ohms / square, the silver nanobeam network spacing is 8-13 μm, and the beam width is 1-2 μm.

[0072] Preferably, the three curing temperatures and times in step S4 are 80°C-100°C for 1 hour, 140°C-160°C for 40 minutes, and 180°C-240°C for 1 hour. The speed of the glue roller is 700-1000 rpm, and the curing time is 80-120 seconds.

[0073] Preferably, the magnetron sputtering temperature in step S5 is 100°C to 250°C, the working gas is Ar gas, the working gas is 99.99% argon gas, and the vacuum degree is 3.0 to 4.0×10 -4 Pa, target sputtering power is 250W~350W, and sputtering time is 40~70min.

[0074] The present invention uses magnetron sputtering to deposit elements such as Fe, Co, Ni, and Zr onto a flexible nanosilver wire mesh substrate. This ensures the shielding film's flexibility. The three-layer structure of magnetic layer, highly conductive layer, and magnetic layer enhances the film's magnetic shielding effectiveness. Furthermore, the flexible substrate's unique mesh structure and high conductivity provide enhanced high-temperature resistance and shielding effectiveness. The flexible substrate's size and shape can be quickly adjusted, expanding the film's applicability.

[0075] Those skilled in the art will readily recognize other embodiments of the present disclosure after considering the disclosure in the specification and examples. The present invention is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the present disclosure being indicated by the claims.

Claims

1. A method for preparing a flexible high-temperature resistant magnetic shielding film, characterized in that: The steps include: (1) Select a glass slide and attach PI double-sided tape and PTFE / PDMS film on one side as the substrate; (2) Prepare silver nanowire solution; (3) Spraying silver nanowire solution on the PTFE / PDMS film to obtain a silver nanobeam network; (4) spin coating and curing the silver nanobeam network to obtain a flexible substrate of the cured silver nanobeam network; (5) A first FeCoNiZr medium-entropy alloy film and a second FeCoNiZr medium-entropy alloy film are magnetron sputtered on both sides of a flexible substrate to obtain a flexible high-temperature resistant magnetic shielding film.

2. The method for preparing a flexible high-temperature resistant magnetic shielding film according to claim 1, characterized in that: In step (2), the concentration of the silver nanowire solution is 0.4 mg / ml to 0.7 mg / ml.

3. The method for preparing a flexible high-temperature resistant magnetic shielding film according to claim 2, characterized in that: In step (3), a silver nanowire solution is sprayed with a spray gun to obtain a silver nanobeam network. The spray gun is connected to a high-purity nitrogen source, and the argon pressure, spray gun spray speed and spray gun distance are controlled during the spraying process.

4. The method for preparing a flexible high-temperature resistant magnetic shielding film according to claim 3, characterized in that: The argon pressure is 0.1-0.3 MPa, the spray gun speed is 0.1-0.3 ml / min, and the spray gun distance is 10-15 cm.

5. The method for preparing a flexible high-temperature resistant magnetic shielding film according to claim 4, characterized in that: In step (4), a spin coating is performed using a glue spreader, the speed of the glue spreader is 700-1000 r / min, and the time is 80s-120s.

6. The method for preparing a flexible high-temperature resistant magnetic shielding film according to claim 5, characterized in that: In step (4), the curing process is specifically as follows: the spin-coated substrate is placed in a drying oven for the first curing. After the curing is completed, the PI film embedded with the silver nanobeam network is removed, the silver nanobeam network side is facing outward, and the PI film is fixed on a glass slide with a high-temperature tape for the second curing. After the curing is completed, the high-temperature tape is removed and fixed with a new high-temperature tape for the third curing.

7. The method for preparing a flexible high-temperature resistant magnetic shielding film according to claim 6, characterized in that: The first curing temperature is 80℃~100℃, and the time is 1h; the second curing temperature is 140℃~160℃, and the time is 40 min; the third curing temperature is 180℃~240℃, and the time is 1h.

8. The method for preparing a flexible high-temperature resistant magnetic shielding film according to claim 7, characterized in that: In step (4), the spacing of the solidified silver nanobeam network is 8-13 μm, and the beam width is 1-2 μm.

9. The method for preparing a flexible high-temperature resistant magnetic shielding film according to claim 8, characterized in that: The component contents of the first FeCoNiZr mesorptive alloy film and the second FeCoNiZr mesorptive alloy film are determined by a high throughput screening composition design method.

10. A flexible high-temperature resistant magnetic shielding film prepared by the method according to claim 9.

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