Shielding material for electromagnetic waves and method for producing the same

Abstract

The present invention relates to an electromagnetic wave shielding material and a method for producing the same, which comprises a base material and a Zn-NiCr shielding layer applied to the surface of the base material, wherein electromagnetic waves flowing in from the outside can be blocked and thereby malfunctions of electrical components can be prevented, and the emission of electromagnetic waves generated from electrical components to the outside can be blocked and thereby damage to the human body can be minimized.

Description

Electromagnetic shielding material and its manufacturing method

[0001] The present invention relates to an electromagnetic shielding material and a method for manufacturing the same, and more particularly, to an electromagnetic shielding material and a method for manufacturing the same that can block electromagnetic waves generated inside and outside a vehicle and prevent abnormal operation of vehicle electrical components.

[0002]

[0003] Electromagnetic shielding refers to preventing noise generated inside electronic components from radiating to the outside, or blocking electromagnetic noise from sunlight or the electromagnetic fields of pedestrians.

[0004] In particular, electronic components that are sensitive to external electromagnetic waves must be shielded from electromagnetic waves to prevent malfunction, and various electromagnetic shielding technologies have been developed for this purpose.

[0005] In addition, as the automobile industry becomes more sophisticated, the number of electrical components installed inside automobiles is increasing. However, research and development of electromagnetic wave blocking technology that can prevent malfunction of electrical components that can lead to safety accidents for drivers and pedestrians is still insufficient.

[0006] These electrical components include automotive controllers, automotive motor housings, and hydrogen vehicle air control valves (ACVs).

[0007] Currently, domestic and international vehicle manufacturers have developed technologies to block electromagnetic waves generated inside and outside the vehicle by incorporating metal wires such as iron or aluminum, carbon-based materials such as carbon nanotubes or pitch, into the housing. However, these technologies increase the overall weight of the housing and require processing to prevent corrosion.

[0008] In addition, when manufacturing a composite capable of blocking electromagnetic waves by dispersing a conductive filler within a polymer matrix, there is a problem in that it is difficult to uniformly disperse the filler within the polymer matrix and the strength of the composite increases due to the filler, making subsequent processing difficult.

[0009]

[0010] The present invention was created to improve the problems of the above-mentioned conventional electromagnetic shielding materials being heavy and difficult to manufacture, and the purpose is to provide an electromagnetic shielding material that is lightweight and has excellent compatibility with other materials, and a method for manufacturing the same.

[0011]

[0012] In order to achieve the above-mentioned purpose, the electromagnetic shielding material according to the present invention includes a base material and a shielding layer coated on the surface of the base material.

[0013] The above shielding layer may include at least one selected from the group consisting of zinc (Zn), nickel (Ni), and chromium (Cr).

[0014] The above shielding layer may be configured to include zinc in an amount of 53 atomic% or more and 63 atomic% or less relative to the total atoms.

[0015] The above shielding layer may be configured to include nickel and chromium in an amount of 37 atomic% or more and 47 atomic% or less relative to the total atoms, and the atomic ratio of the nickel and the chromium may be 1:1.

[0016] The thickness of the above shielding layer can be configured to be 0.1 ㎛ or more and 5 ㎛ or less.

[0017] The above shielding layer can exhibit electromagnetic wave shielding of 40 dB / ㎛ or more and 55 dB / ㎛ or less at an electromagnetic wave wavelength of 0.5 GHz.

[0018] In addition, the method for manufacturing an electromagnetic wave shielding material according to the present invention for laminating a shielding layer for shielding electromagnetic waves on the surface of a base material includes a base material placing step for placing the base material inside a reaction chamber, and a shielding layer forming step for laminating a shielding layer on the outer surface of the base material.

[0019] The above shielding layer forming step may include a first metal deposition step of sputtering a material from a first target containing zinc toward the base material, and a second metal deposition step of sputtering a material from a second target containing nickel and chromium toward the base material.

[0020] The above second target can be configured so that the atomic ratio of nickel and chromium is 1:1.

[0021] The above shielding layer may be configured to include zinc in an amount of 53 atomic% or more and 63 atomic% or less relative to the total atoms.

[0022] The above shielding layer contains nickel and chromium in an amount of 37 atomic% or more and 47 atomic% or less based on the total atoms, and the atomic ratio of the nickel and the chromium may be 1:1.

[0023] In the first metal deposition step, a power of 240 W or more and 250 W or less can be applied to the first target.

[0024] In the second metal deposition step, a power of 160 W or more and 190 W or less can be applied to the second target.

[0025]

[0026] As described above, the electromagnetic shielding material and the manufacturing method thereof according to the present invention have the effect of blocking electromagnetic waves radiated to the outside from an electric component or introduced from the outside, while reducing the overall weight and being applicable to various materials.

[0027]

[0028] Figure 1 is a schematic diagram showing a state in which a conductive filler material is dispersed in a polymer matrix in a conventional electromagnetic shielding material.

[0029] Figure 2 is a schematic diagram showing a cross-section of an electromagnetic shielding material according to a first embodiment of the present invention.

[0030] FIG. 3 is a photograph of a cross-section of an electromagnetic shielding material according to the first embodiment of the present invention, taken using a scanning electron microscope (SEM).

[0031] Figure 4 is a flowchart for explaining a method for manufacturing an electromagnetic shielding material according to a second embodiment of the present invention.

[0032]

[0033] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0034] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail in the detailed description. This is not intended to limit the invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0035] When describing the present invention, terms such as "first" and "second" may be used to describe various components. However, these components may not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, the first component could be referred to as the "second component," and similarly, the second component could also be referred to as the "first component."

[0036] The term "and / or" may include any combination of multiple related listed items or any one of multiple related listed items.

[0037] When a component is referred to as being "connected" or "connected" to another component, it can be understood that it is directly connected or connected to that other component, but that there may be other components in between. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it can be understood that there are no other components in between.

[0038] The terminology used in this application is solely for the purpose of describing specific embodiments and is not intended to limit the present invention. Singular expressions may include plural expressions, unless the context clearly indicates otherwise.

[0039] In this application, terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, and can be understood as not excluding in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0040] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries, such as those defined in the present application, may be interpreted to have a meaning consistent with their meaning in the context of the relevant technology, and, unless explicitly defined herein, may not be interpreted in an idealized or overly formal sense.

[0041] In addition, the following examples are provided to more completely explain to a person having average knowledge in the art, and the shapes and sizes of elements in the drawings may be exaggerated for clearer explanation.

[0042] Figure 1 is a schematic diagram showing a state in which a conductive material filler is dispersed in a polymer matrix in a conventional electromagnetic shielding material.

[0043] Referring to Fig. 1, a conventional electromagnetic shielding material is filled with a filler material (2) such as a metal nanowire, carbon black, or carbon nanotube inside a polymer matrix (1) such as polyethylene (PP), polypropylene (PP), or polycarbonate (PC).

[0044] However, it is difficult to uniformly disperse the filler (2) inside the polymer matrix (1), and there is a problem that the processability of the polymer matrix (1) is reduced when the filler (2) is added to the polymer matrix (1).

[0045] FIG. 2 is a schematic diagram showing a cross-section of an electromagnetic shielding material according to a first embodiment of the present invention, and FIG. 3 is a SEM (Scanning Electron Microscope) photograph showing a cross-section of an electromagnetic shielding material according to a first embodiment of the present invention.

[0046] Referring to FIG. 2, an electromagnetic shielding material according to one embodiment of the present invention includes a base material (10) and a shielding layer (20) coated on the surface of the base material (10).

[0047] The above shielding layer (20) includes at least one from the group consisting of zinc (Zn), nickel (Ni), and chromium (Cr), and most preferably, Zn-NiCr, which includes all of zinc, nickel, and chromium and is lightweight and has excellent shielding properties, can be used as the shielding layer (20).

[0048] To explain in detail, in order to prevent electromagnetic waves from entering from the outside toward the inside of the above-mentioned parent material (10) or from escaping from the inside of the above-mentioned parent material (10) to the outside, a shielding layer (20) is coated on one side of the above-mentioned parent material (10) to provide a multi-layered electromagnetic shielding material.

[0049] The above-mentioned parent material (10) is shown as a flat surface in the first embodiment, but is not limited thereto and may include all shapes formed in various forms, such as curved surfaces, in response to the formation of automobile electrical components.

[0050] The material of the above-mentioned parent material (10) may be, but is not limited to, plastics such as polyethylene (PE), polypropylene (PP), and polycarbonate (PC), or ceramics such as glass, alumina, and zeolite, or composite materials thereof.

[0051] At this time, the shielding layer (20) can be formed using a physical deposition method, and preferably, a physical vapor deposition method (PVD, Physical Vapor Deposition) can be utilized.

[0052] The above physical vapor deposition method can be formed using various methods such as arc ion plating (AIP), sputtering, pulsed laser deposition (PLD), etc. In this embodiment, magnetron sputtering is used, but it is not limited thereto, and the shielding layer (20) can be formed using a conventionally known physical vapor deposition method.

[0053] For example, as in the embodiment of the present invention, a sputtering voltage is applied to a zinc target through PVD equipment using magnetron sputtering, and sputtered zinc atoms are deposited on the base material (10).

[0054] After the zinc atoms are deposited on the base material (10), a sputtering voltage is applied to a nickel-chromium target through PVD equipment using the magnetron sputtering, so that the sputtered nickel atoms and chromium atoms are deposited on the base material (10), thereby forming a Zn-NiCr shielding layer (20).

[0055] The above nickel-chromium target is composed of nickel and chromium in an atomic ratio of 1:1.

[0056] The above shielding layer (20) contains zinc in an amount of 53 atomic% or more and 63 atomic% or less relative to the total atoms.

[0057] If the above shielding layer (20) contains less than 53 atomic% of zinc compared to the total atoms, the shielding performance of the shielding layer (20) is reduced, and thus it cannot sufficiently block electromagnetic waves incident from the outside, which may cause malfunction of internal electrical components.

[0058] In addition, when the shielding layer (20) contains zinc exceeding 63 atomic% of the total atoms, the shielding performance of the shielding layer (20) is improved, but corrosion resistance due to external factors is reduced, so there is a problem that long-term shielding stability is lowered.

[0059] The above shielding layer (20) contains nickel and chromium in an amount of 37 atomic% or more and 47 atomic% or less based on the total atoms, and the atomic ratio of the nickel and the chromium is 1:1.

[0060] When the above shielding layer (20) contains less than 37 atomic% of nickel and chromium relative to the total atoms, the corrosion potential decreases, the tendency to corrode in an external environment increases, and the long-term electromagnetic shielding properties decrease.

[0061] Additionally, when nickel and chromium exceed 47 atomic percent of the total atoms, the corrosion potential increases, improving corrosion resistance but reducing the ability to shield electromagnetic waves from the outside.

[0062] The above shielding layer (20) is formed with an optimal thickness range that can maintain weight reduction while shielding electromagnetic waves from the outside, with a thickness of 0.1 ㎛ or more and 5 ㎛ or less.

[0063] If the thickness of the above shielding layer (20) is less than 0.1㎛, the attenuation of electromagnetic waves flowing in from the outside or electromagnetic waves moving from the inside to the outside may decrease, causing internal electrical components to malfunction.

[0064] In addition, when the thickness of the shielding layer (20) exceeds 5㎛, the additional effect of blocking electromagnetic waves is minimal, the coating time required for forming the shielding layer (20) increases, and the residual stress within the layer increases as a brittle columnar structure is formed.

[0065] The above shielding layer (20) exhibits electromagnetic wave shielding of 40 dB / ㎛ or more and 55 dB / ㎛ or less at 0.5 GHz.

[0066] According to the specific absorption rate (SAR) standard stipulated in the Ministry of Science and ICT Notice No. 2019-4, the general public is stipulated to receive radio waves of 0.08 W / kg for the whole body, 1.6 W / kg for the head and torso, and 4 W / kg for the limbs in the range of 100 kHz to 10 GHz, and measurements were made at an arbitrary value of 0.5 GHz within the range.

[0067] If the above shielding layer (20) exhibits a shielding performance of less than 40 dB / ㎛ at 0.5 GHz, it may cause malfunction of electrical components existing inside the electromagnetic shielding material, and electromagnetic waves emitted from the electrical components may not be sufficiently attenuated, which may have a negative effect on the health of the general public.

[0068] In addition, if the above shielding layer (20) exhibits a performance exceeding 55 dB / ㎛ at 0.5 GHz, the additional electromagnetic wave blocking effect is minimal, and the amount of material consumed for the electromagnetic wave shielding material increases, thereby reducing economic feasibility.

[0069]

[0070] Referring to FIG. 4 below, a method for manufacturing an electromagnetic shielding material according to a second embodiment of the present invention will be described step by step.

[0071] Referring to FIG. 4, a method for manufacturing an electromagnetic shielding material according to the second embodiment of the present invention for laminating a shielding material (20) on the surface of a base material (10) includes a base material placing step (S10) of placing the base material (10) inside a reaction chamber, and a shielding layer forming step (S50) of laminating a shielding layer (20) on the outer surface of the base material (10).

[0072] In the above-mentioned base material mounting step (S10), the base material (10) is mounted inside the reaction chamber of the PVD equipment using magnetron sputtering, and the base material (10) can be mounted using a fixture (not shown in the drawing) for mounting the base material (10).

[0073] In detail, the base material (10) formed of a metal material can be fixed by applying an attractive force due to a magnetic field to the base material (10) using a fixture equipped with a magnet.

[0074] The above shielding layer forming step (S50) includes a first metal deposition step (S51) of sputtering a material from a first target containing zinc toward the base material (10), and a second metal deposition step (S52) of sputtering a material from a second target containing nickel and chromium toward the base material (10).

[0075] The above second target has an atomic ratio of nickel and chromium of 1:1.

[0076] The above shielding layer (20) contains zinc in an amount of 53 atomic% or more and 63 atomic% or less relative to the total atoms.

[0077] If the above shielding layer (20) contains less than 53 atomic% of zinc compared to the total atoms, the shielding performance of the shielding layer (20) is reduced, and thus it cannot sufficiently block electromagnetic waves incident from the outside, which may cause malfunction of internal electrical components.

[0078] In addition, when the shielding layer (20) contains more than 63 atomic% of zinc compared to the total atoms, the shielding performance of the shielding layer (20) is improved, but corrosion resistance due to external factors is reduced, so there is a problem that long-term shielding stability is reduced.

[0079] The above shielding layer (20) contains nickel and chromium in an amount of 37 atomic% or more and 47 atomic% or less based on the total atoms, and the atomic ratio of the nickel and the chromium is 1:1.

[0080] When the above shielding layer (20) contains less than 37 atomic% of nickel and chromium relative to the total atoms, the corrosion potential decreases, the tendency to corrode in an external environment increases, and the long-term electromagnetic shielding properties decrease.

[0081] Additionally, when nickel and chromium exceed 47 atomic percent of the total atoms, the corrosion potential increases, improving corrosion resistance but reducing the ability to shield electromagnetic waves from the outside.

[0082] In the first metal deposition step (S51), power of 240 W or more and 250 W or less is applied to the first target.

[0083] When the amount of power applied to the first target is less than 240 W, the amount of zinc sputtered from the first target decreases, thereby reducing the amount of electromagnetic waves blocked from the outside of the shielding material (20).

[0084] When the amount of power applied to the first target exceeds 250 W, the amount of zinc sputtered from the first target increases, increasing the electromagnetic shielding ability of the shielding material (20), but weakening the corrosion resistance.

[0085] Additionally, in the second metal deposition step (S52), power of 160 W or more and 190 W or less is applied to the second target.

[0086] When the amount of power applied to the second target is less than 160 W, there is a problem in that the amount of nickel and chromium sputtered from the second target decreases, thereby lowering the corrosion resistance of the shielding material (20).

[0087] When the amount of power applied to the second target exceeds 190 W, the amount of nickel and chromium sputtered from the second target increases, thereby increasing the corrosion resistance of the shielding material (20), but reducing the amount of electromagnetic waves blocked from the outside.

[0088]

[0089] In addition, the method for manufacturing an electromagnetic shielding material according to the second embodiment of the present invention further includes a vacuum forming step (S20) of maintaining the internal atmosphere of the reaction chamber in a vacuum state while the base material (10) is placed inside the reaction chamber after the base material placing step (S10), a plasma forming step (S30) of injecting Ar gas into the interior of the reaction chamber and increasing the temperature of the chamber to form a plasma state in which Ar ions are generated, and a cleaning step (S40) of cleaning the surface of the base material (10) by colliding the Ar ions with the surface of the base material (10).

[0090] In the above vacuum forming step (S20), a fixture on which the above-mentioned parent material (10) is placed is placed inside the reaction chamber, and the internal atmosphere of the reaction chamber is formed and maintained in a vacuum state.

[0091] Next, in the plasma formation step (S30), Ar gas is supplied as a process gas, and a temperature control device is used to increase the temperature to form a plasma state in which Ar ions are formed inside the reaction chamber.

[0092] Thereafter, in the above cleaning step (S40), a bias voltage is applied to the bias electrode, and Ar ions are accelerated to collide with the surface of the base material (10), thereby cleaning the surface of the base material (10).

[0093] This is to first perform an etching process to remove the oxide layer and impurities naturally formed on the surface of the above-mentioned base material (10), thereby increasing the adhesive strength between the electromagnetic shielding layer (20) and the base material (10).

[0094] In addition, in this case, the bias voltage can be maintained in the range of 200 V or more and 400 V or less. If the bias voltage is less than 200 V, the acceleration voltage of Ar ions decreases, which reduces the hardness of the shielding material. If the bias voltage exceeds 400 V, the lattice arrangement may become irregular, which may cause a problem of reduced adhesion of the shielding material.

[0095]

[0096] Below, the results of a comparison of physical property evaluations between examples manufactured by applying the manufacturing method of an electromagnetic shielding material according to the present invention will be described.

[0097]

[0098] Example

[0099] First, a flat plate-shaped base material (10) was placed inside a reaction chamber of a sputtering device, and while the inside of the reaction chamber was in a vacuum, a plasma state was created using Ar gas, and the inside of the chamber was heated to 80°C to activate the surface of the base material made of SUS440C stainless steel, and then a bias voltage of 300 V was applied to cause Ar ions to collide with the surface, thereby cleaning the surface of the base material (10).

[0100] After cleaning the surface of the above-mentioned parent material (10), a first metal deposition step (S51) was performed by applying a predetermined output to a first target containing zinc through magnetron sputtering to sputter metal atoms containing zinc toward the above-mentioned parent material (10).

[0101] After the first metal deposition step (S51) was performed, a second metal deposition step (S52) was performed to apply a predetermined power to a second target containing nickel and chromium (atomic ratio of nickel and chromium is 1:1) by magnetron sputtering to sputter metal atoms containing nickel and chromium toward the base material (10), thereby manufacturing Examples 1 to 7.

[0102] The power applied to form and accelerate plasma in the first target and the second target and the composition of the shielding layer (20) (Zn-NiCr) are as shown in Table 1.

[0103]

[0104] Classification Approved Power (W) Atomic Ratio 1st Target 2nd Target Zn-NiCr Example 1 250 200 52:48 Example 2 240 190 53:47 Example 3 250 210 56:44 Example 4 240 240 59:41 Example 5 250 170 61:39 Example 6 240 160 63:37 Example 7 250 160 64:36

[0105]

[0106] Shielding performance evaluation

[0107] First, to evaluate the surface resistance of the shielding layer (20), a four-point probe was used to measure it.

[0108] In general, sheet resistance can be determined by measuring the current flowing through the sample after applying a certain voltage to the sample. Sheet resistance is proportional to the applied voltage (V) and the length of the sample (L), and inversely proportional to the current flowing through the sample (I) and the width of the sample (W). Detailed measurement methods can be referenced from known technologies, so a detailed explanation is omitted.

[0109] Thereafter, in order to evaluate the shielding performance of the shielding layer, the shielding performance of the shielding layer (20) according to Examples 1 to 7 was compared at 0.5 GHz according to the International Standard for Automotive Narrowband Radiation (CISPR 25) established by the International Special Committee on Radio Interference (CISPR).

[0110]

[0111] Corrosion resistance evaluation

[0112] In addition, in order to evaluate the corrosion resistance of the shielding layer (20), the corrosion potential and corrosion current density were evaluated using a potentiostat / constant current device (AMETEK PARSTAT 4000A).

[0113] Specifically, an AgCl / KCl electrode was used as a reference electrode, and Pt was used as a counter electrode, and measurements were made in the range of -0.8 V to 0.4 V at a scan rate of 1 mV / s in a 3.5 mass% sodium chloride solution.

[0114]

[0115] Shielding performance (350 nm thickness) Corrosion resistance evaluation Resistivity (Ω / sq.) Shielding effectiveness (dB) Corrosion potential E corr (V vs Ag / AgCl) Corrosion current density I corr (V vs Ag / AgCl) Example 1 2.7 37 - 0.38 30.59 Example 2 1.64 2 - 0.39 50.63 Example 3 1.14 6 - 0.40 84.77 Example 4 0.84 9 - 0.41 29.52 Example 5 0.75 0 - 0.43 711.31 Example 6 0.65 51 - 0.47 214.28 Example 7 0.65 2 - 0.48 114.93

[0116]

[0117] According to the shielding performance evaluation results in Table 2 above, it can be confirmed that as the zinc ratio in the shielding layer (20) increases, the resistivity decreases from 2.7Ω / sq. (Example 1) to 0.6Ω / sq. (Example 7) and the shielding performance increases from 37dB (Example 1) to 52dB (Example 7).

[0118] In addition, as a result of the corrosion resistance evaluation, it can be confirmed that as the zinc ratio in the shielding layer (20) increases, the corrosion potential decreases from -0.383 V (Example 1) to -0.481 V (Example 7) compared to the reference potential (Ag / AgCl), and the corrosion current density increases from 0.59 μA (Example 1) to 14.93 μA (Example 7).

[0119] As a result, it was confirmed that the shielding layer (20) containing 52 mass% or more and 64 mass% or less of zinc and 36 mass% or more and 48 mass% of nickel-chromium (the mass ratio of nickel and chromium is 1:1) has sufficient shielding performance while also having the effect of improving corrosion resistance.

[0120]

[0121] Although the present invention has been described in detail through specific examples, this is for the purpose of specifically explaining the present invention, and the present invention is not limited thereto, and it is clear that the present invention can be modified or improved by a person having ordinary knowledge in the relevant field within the technical spirit of the present invention.

[0122] All simple modifications or changes of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be made clear by the appended claims.

Claims

1. Parent material; and A shielding layer coated on the surface of the above-mentioned parent material; Including, The above shielding layer is, An electromagnetic shielding material comprising at least one element from the group consisting of zinc (Zn), nickel (Ni) and chromium (Cr).

2. In claim 1, The above shielding layer is, Electromagnetic shielding material containing zinc in an amount of 53 to 63 atomic% of total atoms.

3. In claim 1, The above shielding layer is, An electromagnetic shielding material comprising nickel and chromium in an amount of 37 atomic% or more and 47 atomic% or less based on the total atoms, wherein the atomic ratio of the nickel and the chromium is 1:

1.

4. In claim 1, The above shielding layer is, Electromagnetic shielding material with a thickness of 0.1㎛ or more and 5㎛ or less.

5. In claim 1, The above shielding layer is, Electromagnetic shielding material that exhibits electromagnetic shielding of 40 dB / ㎛ or more and 55 dB / ㎛ or less at 0.5 GHz.

6. A method for laminating a shielding layer that shields electromagnetic waves on the surface of a base material, A base material mounting step of mounting the base material inside the reaction chamber; and A shielding layer forming step of laminating a shielding layer on the outer surface of the above-mentioned parent material; A method for manufacturing an electromagnetic shielding material including:

7. In claim 6, The above shielding layer formation step is, A first metal deposition step of sputtering a material from a first target containing zinc toward the base material; and A second metal deposition step of sputtering a material from a second target containing nickel and chromium toward the base material; A method for manufacturing an electromagnetic shielding material including:

8. In claim 7, The second target above is, A method for manufacturing an electromagnetic shielding material characterized in that the atomic ratio of nickel and chromium is 1:

1.

9. In claim 6, The above shielding layer is, A method for manufacturing an electromagnetic shielding material containing zinc in an amount of 53 to 63 atomic% of total atoms.

10. In claim 6, The above shielding layer is, A method for manufacturing an electromagnetic shielding material comprising nickel and chromium in an amount of 37 atomic% or more and 47 atomic% or less based on total atoms, wherein the atomic ratio of the nickel and the chromium is 1:

1.

11. In claim 7, In the above first metal lamination step, A method for manufacturing an electromagnetic shielding material in which a power of 240 W or more and 250 W or less is applied to the above first target.

12. In claim 7, In the second metal lamination step, A method for manufacturing an electromagnetic shielding material in which a power of 160 W or more and 190 W or less is applied to the second target.

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