Cu-based alloy having electromagnetic shielding function and electromagnetic shielding member using same

Abstract

An alloy for shielding electromagnetic waves, proposed in one aspect of the present invention, comprises: a Cu-based first phase; and a second precipitated phase comprising spherical particles or fragmented dendrites separated and precipitated from the first phase, wherein the second precipitated phase is rich in ferromagnetic elements such as Fe.

Description

Cu matrix alloy having electromagnetic shielding function and electromagnetic shielding member using the same

[0001] The present invention relates to a Cu-based alloy having an electromagnetic shielding function, a method for manufacturing the same, and an electromagnetic shielding member using the same. The present invention claims the benefit of the filing date of Korean Patent Application No. 10-2025-0036016 filed with the Korean Intellectual Property Office on March 20, 2025, and the entire contents thereof are incorporated into the present invention.

[0002] Electromagnetic shielding is performed to protect internal components of a device and to block external interference, and it is generally achieved by using materials that prevent electromagnetic interference. Such shielding is often formed by constructing a metal screen to surround the interior of a device susceptible to electromagnetic interference, thereby absorbing interference transmitted through the air. Metal materials such as copper (Cu), aluminum (Al), or iron (Fe) have been used for these metal screens.

[0003] Among these metallic materials, non-ferrous metals, represented by Cu, are known to be effective at shielding electrical noise but relatively weak at shielding magnetic noise. On the other hand, although Fe is effective at shielding magnetic noise, it generates heat during electromagnetic wave interactions and has the problem of being susceptible to corrosion.

[0004] To overcome these problems, a method of alternately stacking Cu and Fe foils was considered, but this method is very cumbersome and incurs high costs, limiting its commercialization.

[0005] As a method to effectively implement the aforementioned electromagnetic shielding, recent research has been conducted to approach such shielding through the development of alloy compositions.

[0006] In particular, active development of alloys to achieve effective electromagnetic shielding has recently been underway by alloying Cu and Fe to finely and uniformly distribute particles with high Fe content within the Cu matrix. However, to date, particle precipitation within the cast structure has resulted in the growth of columnar dendritic forms, which limits isotropic properties and restricts the ability to achieve fine and uniform particle distribution. Consequently, there is a need to develop alloy compositions and manufacturing methods capable of finely and uniformly distributing spherical precipitates within the Cu matrix.

[0007] The present invention aims to propose a composition in which a ferromagnetic element is added to Cu, which has ferromagnetism at room temperature and has a positive heat of mixing with Cu to form a second precipitated phase through phase separation, and wherein the second precipitated phase rich in the ferromagnetic element can be precipitated as spherical or fragmented dendritic particles by utilizing the negative heat of mixing relationship and solid solubility between the ferromagnetic element and Si.

[0008] The present invention is also intended to identify a compositional region in which a solid solution containing the ferromagnetic element can be formed as a fine precipitate on a Cu matrix when different processes are used, and to identify the optimal combination of composition and process conditions for an alloy that can be used as an electromagnetic shielding member.

[0009] Another objective of the present invention is to propose a composition for forming spherical precipitates within a casting structure by additionally including elements that influence the sphericity of the precipitate phase.

[0010] Furthermore, the objective of the present invention is to solve the aforementioned problems by proposing an alloy of a new composition that possesses excellent electromagnetic shielding capabilities, excellent processability, mechanical properties, and price competitiveness, and an electromagnetic shielding member manufactured as a composite material using this alloy.

[0011] However, the problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned problems will be clearly understood by those skilled in the art from the description below.

[0012] In order to solve the above-mentioned problem, an electromagnetic shielding alloy proposed in one aspect of the present invention comprises: a first phase consisting of a Cu matrix; and a second precipitate phase rich in one or more ferromagnetic elements selected from Fe, Co, and Ni; wherein the second precipitate phase comprises spherical or fragmented dendritic precipitate particles.

[0013] According to one embodiment, the second precipitated phase may further include Si.

[0014] According to one embodiment, the alloy may have a composition represented by Formula 1.

[0015] [Equation 1]

[0016] Cu x TM 100-x-y Si y

[0017] In the above Equation 1,

[0018] TM must include at least one selected from Fe, Co, and Ni, and optionally includes at least one selected from Cr, Mn, V, Mg, Zn, Ta, and Bi, and

[0019] x is 51 to 94 wt. % and y is 0.1 to 5 wt. %.

[0020] According to one embodiment, in Formula 1, TM may contain a total content of Fe, Ni, and Co of 50 at. % or more.

[0021] According to one embodiment, the alloy may be obtained by performing only a casting process without a thermal-mechanical processing (TMT) method.

[0022] According to one embodiment, the alloy may be obtained by performing a casting process and a thermomechanical process (TMT) together.

[0023] According to one embodiment, the alloy may include an FCC structure of a first phase of a Cu matrix.

[0024] According to one embodiment, the second precipitate rich in one or more ferromagnetic elements selected from Fe, Co, and Ni may have a total content of Fe, Co, and Ni among the metal elements included in the second precipitate that is 50 at.% or more.

[0025] According to one embodiment, the second precipitate phase may not include columnar dendrite (CD) precipitate particles having an equivalent original diameter of more than 10 μm.

[0026] According to one embodiment, the precipitated particles of the second precipitated phase may have an equivalent original diameter of 10 μm or less.

[0027] According to one embodiment, the TM may be Fe. That is, the alloy is Cu x Fe 100-x-y Si y It has a composition expressed as, where x is 51 to 94 wt. % and y is 0.1 to 5 wt. %.

[0028] According to one embodiment, when the TM is Fe, the second precipitated phase may include one or more phases of Fe solid solution, FeSi, Fe2Si, Fe3Si, and Fe5Si3.

[0029] According to one embodiment, when the TM is Fe, the x may be 70 to 92 wt. % and the y may be 0.2 to 3.4 wt. %.

[0030] According to one embodiment, when TM is Fe, the electromagnetic shielding alloy is △T (liquid temperature (T L) - Fe precipitate formation temperature (T Fe )) may be 150 K or less.

[0031] According to one embodiment, the types of elements constituting the TM are three or more, and the three or more elements may constitute a Complex Concentrated Alloy (CCA).

[0032] According to one embodiment, when the TM is composed of three or more elements, the second precipitated phase may include one or more phases among FCC CCA solid solution, (CCA)Si, (CCA)2Si, (CCA)3Si, and (CCA)5Si3.

[0033] According to one embodiment, when the TM includes one or more of Mg, Zn, Ta, and Bi, the total content of Mg, Zn, Ta, and Bi may be 5 wt.% or less with respect to the total weight of the TM.

[0034] A method for manufacturing an electromagnetic shielding alloy proposed in another aspect of the present invention comprises: a step of melting a Cu metal; a step of adding a metal element including one or more ferromagnetic elements selected from Fe, Co, and Ni and Si to the molten Cu metal; and a step of casting and cooling the molten alloy.

[0035] According to one embodiment, the metal elements may further include one or more elements selected from Cr, Mn, V, Mg, Zn, Ta, and Bi.

[0036] According to one embodiment, the alloy manufactured above may be an electromagnetic shielding alloy according to one embodiment of the present invention described above.

[0037] According to one embodiment, the step of cooling the molten alloy after casting may be a step of cooling after casting in a single liquid phase region greater than the solubility gap, and more specifically, the cooling may be through the solubility gap. In addition, for an alloy that is melted in a single liquid phase region and has a sufficiently uniform compositional distribution, if a cooling process through the solubility gap is performed, it may be separated into two liquid phases rich in Cu and Fe, respectively, and then the liquid phase rich in Cu may be formed as the matrix phase and the liquid phase rich in Fe may be formed as the precipitate phase.

[0038] According to one embodiment, cooling through the solubility gap is △T (=liquid-liquid phase separation temperature (T L ) - Fe precipitate formation temperature (T Fe It may pass so as to satisfy 150 K or less.

[0039] According to one embodiment, after the step of cooling the molten alloy after casting, the method may further include the step of performing a post-processing step using a thermal-mechanical (TMT) method.

[0040] An electromagnetic shielding member proposed in another aspect of the present invention comprises an alloy and a polymer resin according to one embodiment of the present invention.

[0041] By proposing an alloy with a novel composition not previously presented, the present invention enables the fine and uniform distribution of spherical or fragmented dendritic precipitates in a Cu matrix, and provides an alloy with excellent processability and mechanical properties while improving electromagnetic shielding ability through a second precipitate phase with excellent magnetic shielding ability.

[0042] Specifically, the above Cu matrix has high electrical conductivity and can contribute to the electromagnetic shielding ability of the alloy by effectively reflecting radio waves, and the second precipitate phase rich in ferromagnetic elements can contribute to the electromagnetic shielding ability of the alloy by absorbing magnetic waves that are not reflected from the surface of the Cu matrix.

[0043] In the present invention, an appropriate compositional region in a Cu-Fe-Si alloy in which spherical or fragmented dendritic precipitates are formed was identified, and by including one or more ferromagnetic elements selected from Fe, Co, and Ni to appropriately control the particle distribution and shape of a second precipitate with excellent magnetic shielding ability, it was possible to achieve an excellent electromagnetic shielding effect. In addition, since the spherical or fragmented dendritic precipitates are finely and uniformly distributed within the matrix, not only is the isotropy of the electromagnetic shielding ability excellent, but the limitations of processability and mechanical properties caused by stress concentration due to columnar dendritic particles can also be overcome.

[0044] In addition, by using the alloy composition proposed in the present invention, it is possible to provide various electromagnetic shielding members with excellent high-conductivity electromagnetic shielding capabilities.

[0045] However, the effects of the present invention are not limited to those described above, but include all effects naturally realized through the various configurations proposed in the present invention.

[0046] Figure 1 shows the Cu-Fe, Fe-Si, and Si-Cu binary phase diagrams based on three elements Cu, Fe, and Si according to one embodiment of the present invention, plotted on the Cu-Fe-Si ternary Gibbs triangle.

[0047] Figure 2 shows Cu x Fe 100-x-y Si y This is a pseudo-binary phase diagram for x=94, 90, 80, 60, and 50 wt. % in a ternary alloy system.

[0048] FIG. 3 is a phase diagram showing the phase change behavior in alloy systems with various other metal elements (Co, Ni, Cr, Mn and Si) added to a Cu-Fe-based composition, and is a pseudo-binary phase diagram of multi-component alloy systems (a) Cu-(FeCoNi), (b) Cu-(FeCoNiCr), (c) Cu-(FeCoNiMn), (d) Cu-(FeCoNiCrMn), (e) Cu-(FeCoNiCrSi) and (f) Cu-(FeCoNiMnSi).

[0049] Figure 4 shows the microstructure of Comparative Example 1 composition, in which the second precipitate phase within the Cu matrix is ​​formed as (a) dendritic, and Example 1 composition, in which it is formed as (b) spherical, and the results of analysis using a backscattered electron (BSE) detector in a scanning electron microscope (SEM).

[0050] FIG. 5 is an SEM image showing the shape of the second precipitate formed in the Cu matrix as the microstructure after casting of (a) Example 4, (b) Example 5, (c) Example 6, (d) Example 8, (e) Example 11, and (f) Example 14.

[0051] Figure 6 shows Cu 90 Fe 10-y Si y This is a pseudo-binary phase diagram of a ternary alloy system.

[0052] FIG. 7 is an SEM image showing the shape of a second precipitate formed in a Cu matrix in experimental examples (Comparative Examples 5 to 8, Examples 19 to 21) containing a Complex Concentrated Alloy (CCA) with an equiatomic ratio in a Cu matrix.

[0053] Figure 8 shows the XRD analysis results of (a) Example 5, (b) Example 8, and (c) Comparative Example 2.

[0054] Figure 9 shows Cu x Fe 99-x Si 1.0 and Cu x Fe 98.6-x Si 1.4 The solidification behavior and microstructural differences and final microstructures during cooling in the liquid phase of (a) Example 4 and (b) Example 5, which are compositions on the pseudo-binary phase diagram of a ternary alloy system, are shown.

[0055] FIG. 10 is △T (liquid temperature (T) of Examples 4, 5, 6, 8, 11, 12, 14, and 15. L ) - Fe precipitate formation temperature (T Fe )) represented.

[0056] Figure 11 is a graph showing the influence of each element on (a) the nucleation behavior affecting grain size and (b) the relative columnar growth restriction factor (G) for each element added to the Cu matrix as a criterion for additionally adding a third element to control the nucleation and growth rate of the second precipitate phase in Cu-Fe-Si or Cu-CCA-Si alloys.

[0057] Figure 12 is a low-magnification SEM image showing the microstructure of Example 30.

[0058] Figure 13 is a high-magnification SEM image of Example 30 and an SEM-EDS elemental mapping image that can identify the constituent elements of the precipitate formed on the Cu matrix for the corresponding microstructure.

[0059] Figure 14 is an elemental line scan image of SEM-EDS that can confirm the concentration distribution of the second phase precipitated on the Cu matrix of Example 30.

[0060] The embodiments of the present invention are illustrative for the purpose of explaining the technical concept of the present invention. The scope of rights according to the present invention is not limited to the embodiments presented below or the specific description thereof.

[0061] All technical and scientific terms used in this invention, unless otherwise defined, have the meaning generally understood by those skilled in the art to which this invention pertains. All terms used in this invention are selected for the purpose of further explaining this invention and are not selected to limit the scope of rights according to this invention.

[0062] Expressions such as "comprising," "having," "having," etc. used in the present invention should be understood as open-ended terms implying the possibility of including other embodiments, unless otherwise stated in the phrase or sentence containing such expressions.

[0063] Unless otherwise stated, singular expressions described in the present invention may include the meaning of the plural form, and this applies likewise to singular expressions described in the claims.

[0064] Embodiments of the present invention will be described below with reference to the attached drawings. Furthermore, in the description of the following embodiments, the description of identical or corresponding components may be omitted. However, even if a description of a component is omitted, it is not intended that such component is not included in any embodiment.

[0065] Among the various methods of achieving electromagnetic shielding through alloys, the importance of research on alloys that utilize the combined advantages of Cu and Fe has recently been highlighted.

[0066] Through multiple experiments and studies, the inventors noted that when a Cu-10Fe alloy is cast among alloys using Cu and Fe, a material is formed in which a secondary Fe precipitate phase is precipitated in the Cu matrix through the solubility gap, and that this material is effective for electromagnetic shielding. The alloy of this composition has excellent electromagnetic shielding performance and economic advantages. However, in the alloy of this composition, the formation of columnar dendrites of the secondary Fe precipitate phase separated in the Cu matrix reduces the processability of the alloy due to localized stress concentration during deformation, which makes severe plastic deformation—an essential requirement in the application process of electromagnetic shielding materials—difficult.

[0067] To solve this problem, the inventors have devised a composition control method to ensure machinability in the Cu-Fe alloy composition, wherein the Fe-rich secondary precipitate precipitates as uniform, nearly spherical particles instead of forming a dendritic structure during casting, and have completed the present invention.

[0068] In addition, the embodiments of the present invention propose a composition combination that exhibits optimal electromagnetic shielding performance by moving away from the conventional Cu-10Fe alloy composition and adjusting the ratio of Cu to Fe or mixing in other metal elements. Through this, it is possible to minimize heat generation and corrosion problems that occur during the process of Fe-based alloys shielding electromagnetic waves, while simultaneously achieving excellent shielding performance. In particular, electromagnetic shielding performance can be maximized by controlling the microstructure of Cu and Fe and ensuring they are uniformly distributed within the matrix.

[0069] The combination of metal components for such specialized alloy design can start from the enthalpy relationship between the metals.

[0070]

[0071] The table above shows the mixing heat relationships between each heterogeneous element (unit: kJ / mol). Through this, it can be confirmed that Cu and Fe have a positive mixing heat relationship (+13 kJ / mol), and the mixing heat relationships between various other metals—for example, Cu and Fe with V, Cr, Mb, Mo, Ta, Mn, etc.—can also be confirmed. Meanwhile, it can be confirmed that Fe and Si have a particularly high level of negative mixing heat (-35 kJ / mol, about twice the mixing heat between Cu and Si).

[0072] Considering these points, when alloying with Si, a relatively inexpensive element, the difference in mixing heat between Si and the phase-separating element from Cu is much greater than the difference between Cu and Si; therefore, Si may prefer to bond with the phase-separating element (e.g., Fe) rather than with the Cu matrix. Accordingly, the addition of Si is expected to play a role in controlling the stable alloying of other alloy components, including Fe, which will form a precipitate phase in the alloy of the present invention.

[0073]

[0074] By paying attention to the mixing heat relationships of each of these elements, it is possible to design an alloy composition capable of achieving the aforementioned goal. For example, among the group of elements having a positive mixing heat of a binary system with Cu, the ferromagnetic elements Fe, Co, and Ni can be primarily selected.

[0075] In addition, in some embodiments, by noting the large negative heat of mixing relationship between Fe and Si, the addition of Si can induce Fe to form a precipitate phase together with Si through casting. That is, in some embodiments, the second precipitate phase may further include Si.

[0076] In the alloy design described above, adding Si elements, which possess a large negative heat of mixing in relation to the phase-separating elements (particularly Fe), has the effect of inhibiting the growth of the precipitates of the phase-separating elements. This can induce the formation of small dendrites or completely fragmented dendrites. Alternatively, by inducing a preferred bond between the phase-separating elements and Si, Fe-rich precipitates can be directly precipitated as spherical particles. These spherical, Fe-rich precipitates may have a relatively slower growth rate.

[0077] Next, in order to ensure sufficient electromagnetic shielding within the precipitate phase among the above elements, the range of 50 at. % or more of the TM (Transition Metal) can be limited to ferromagnetic elements such as Fe, Ni, and Co.

[0078] The inventors confirmed that precipitated particles of various shapes can be produced during casting in Cu-Fe-Si alloys depending on the difference in composition, and classified the regions where an Fe-rich second precipitate phase is formed in Cu-Fe-Si alloys according to the shape of the precipitated particles and showed them in FIG. 1. Here, the Fe content in the Fe-rich second precipitate phase is preferably 50 at. % or more to ensure magnetic shielding ability, and Fe can be substituted with Co or Ni, which are ferromagnetic elements.

[0079] Hereinafter, with reference to the images shown in FIGS. 1 to 3, the composition proposed in the present invention and the experimental examples from which these compositions were derived will be described in detail.

[0080] FIG. 1 is a Cu-Fe, Fe-Si, and Si-Cu binary phase diagram based on three elements, Cu, Fe, and Si, according to one embodiment of the present invention, plotted on a Cu-Fe-Si ternary Gibbs triangle. The inventors indicated a compositional region forming a second precipitate phase containing Fe-rich and completely fragmented dendritic precipitates during casting on a Cu matrix as a hatched area, and a compositional region forming a second precipitate phase containing Fe-rich and spherical precipitates during casting as a black filled area.

[0081] More specifically, the shaded area within the Cu-Fe-Si ternary Gibbs triangle of FIG. 1 represents a region where the precipitation of an Fe-rich solid solution alloy occurs predominantly without the precipitation of other Fe-Si intermetallic compounds, and includes each of the regions described below according to one embodiment of the present invention. The shaded composition range, i.e., Cu 51 wt.% or more and 94 wt.% or less, and Si 0.1 wt.% or more and 5 wt.% or less, is a region where spherical or fragmented dendritic precipitate particles with an equivalent diameter of 10 μm or less are formed. The black-filled area, i.e., the composition range of Cu 70 wt.% or more and 92 wt.% or less, and Si 0.2 wt.% or more and 3.4 wt.% or less, is a region where a spherical second precipitate phase is predominantly formed.

[0082] Figure 2 shows Cu x Fe 100-x-y Si yThis is a pseudo-binary phase diagram for x=94, 90, 80, 60, and 50 wt / % in a ternary alloy system. The calculated phase diagram indicates the regions where Fe-rich solid solution second precipitates are expected to form, regions where M(Fe,Cu)-Si intermetallic compounds are expected to form, and regions where liquid-liquid phase separation is expected to occur. Specifically, the region where Fe-rich solid solution second precipitates are expected to form is indicated by a square dotted line, the region where M(Fe,Cu)-Si intermetallic compounds are expected to form is indicated by a dashed line, and the region where liquid-liquid phase separation is expected to occur is indicated by a hatch. For the compositions represented by the square dotted lines, Fe-rich solid solution second precipitates form first upon solidification, and among them, the compositions included in the hatched region are highly likely to form spherical Fe-rich solid solution second precipitates. The compositions in the dashed regions are the areas where M(Fe,Cu)-Si intermetallic compounds are formed first during solidification.

[0083] The inventors designed the alloy composition of the present invention based on the pseudo-binary phase diagrams shown in FIG. 2.

[0084] Cu of Fig. 2 x Fe 100-x-y Si y By looking at the pseudo-binary phase diagram of the ternary alloy system, the appropriate Si content that can be dissolved in Fe can be determined, and the characteristics of the precipitated phases in each compositional region can be predicted based on the Si content.

[0085] First, in the region where the Cu content (x) is 51 to 94 wt.%, a composition in which the Si content (y) is 0.1 or more and 5 wt.% or less may form a second solid solution precipitate phase rich in Fe content suitable for electromagnetic shielding. At this time, when the Cu content (x) is less than 51 wt.%, a phase inversion between the first and second phases occurs, which is undesirable as it may cause the precipitate composition to change from a composition rich in Fe to a composition rich in Cu. In addition, when the Cu content (x) is 94 wt.% or more, the electromagnetic shielding ability may be reduced due to the insufficient fraction of Fe precipitates. Finally, when the Si content (y) exceeds 5 wt.%, an Fe-Si compound phase is mainly formed, which may cause the magnetic shielding ability to decrease rapidly.

[0086] Meanwhile, in the region where the Cu content (x) is 70 wt.% to 92 wt.% and the Si content (y) is 0.2 wt.% to 3.4 wt.%, spherical precipitates rich in Fe content can be precipitated as a second precipitate phase in the region filled in black in FIG. 1. In the alloy compositions of the present invention, the Fe-rich second precipitate phase passes through a limited solidification range near the solubility gap due to the addition of Si during cooling, making it easy to control the spherical shape. Furthermore, the growth rate of precipitates with high Si content is significantly reduced compared to precipitates having an FCC / BCC structure that precipitate in alloys that do not contain Si. Therefore, in this composition range, spherical second phase precipitation is possible with only a single casting process, thereby enabling superior processability and electromagnetic shielding capabilities. The second precipitate phase may include spherical particles with a diameter of 5 μm or less or completely fragmented dendritic precipitates with a length of 5 μm or less. Therefore, the composition of this region may be the most desirable region in a Cu-Fe-Si ternary alloy. When the Cu content (x) is 70 wt.% or less, coarse precipitates with an equivalent diameter exceeding 10 μm may be formed due to the excessive Fe content. In addition, when the Cu content (x) is 92 wt.% or more, as shown in FIG. 2, there is no liquid-liquid phase separation region, so it may be difficult to form precipitates with an equivalent diameter of 10 μm or less.

[0087] According to one embodiment, if the spherical precipitated particles are not perfectly spherical or have a fragmented dendritic shape, the size of the precipitated particles can be evaluated by the Equivalent Circle Diameter (ECD). The Equivalent Circle Diameter and the diameter can be measured through microscopic observation. In this specification, the Equivalent Circle Diameter of a particle refers to a value converted into the diameter of a circle having an area equal to the actual area of ​​the particle, regardless of its shape.

[0088] According to one embodiment, the precipitated particles of the second precipitated phase may have an equivalent circular diameter of 10 μm or less. More specifically, the equivalent circular diameter of the second precipitated phase may be 0.1 μm, 0.5 μm or more, or 1 μm or more, and independently thereof, may be 10 μm or less, 9 μm or less, 8 μm or less, 7 μm or less, 6 μm or less, or 5 μm or less.

[0089] As such, embodiments of the present invention can produce alloys having second precipitates of various shapes in each region while providing compositions of Cu matrix alloys with excellent electromagnetic shielding ability.

[0090] FIG. 3 is a phase diagram showing phase changes in alloy systems in which various other metal elements (Co, Ni, Cr, Mn and Si) are added to a Cu-Fe-based composition, and is a pseudo-binary phase diagram of multi-component alloy systems (a) Cu-(FeCoNi), (b) Cu-(FeCoNiCr), (c) Cu-(FeCoNiMn), (d) Cu-(FeCoNiCrMn), (e) Cu-(FeCoNiCrSi) and (f) Cu-(FeCoNiMnSi).

[0091] Through the phase diagrams of each alloy composition in Figures 3 (a) to (f) above, it can be confirmed that the shape of the phase diagram is similar to the Cu-Fe binary phase diagram in Figure 3 when a Complex Concentrated Alloy (CCA) is formed by replacing at least a portion of Fe with one or more elements selected from Co, Ni, Cr, and Mn, and when Si is additionally added thereto. These results suggest that control of precipitated phases based on phase separation is possible in the corresponding compositions, similar to that in the Cu-Fe binary alloy system. Even when Fe is replaced with the aforementioned elements, it is desirable that Fe, Ni, and Co, as ferromagnetic elements, account for at least 50 at.% of the elements excluding Cu and Si.

[0092] The embodiment corresponding to the Cu matrix alloy in which spherical precipitate particles proposed in the present invention are formed as a second precipitate phase is not necessarily limited to a Cu-Fe-Si ternary alloy. According to one embodiment, in addition to the Cu-Fe-Si ternary alloy, the alloy may be composed by replacing the Fe with a complex supersolid solution alloy (CCA) containing three or more components selected from the group of alloy elements consisting of Fe, Co, Ni, V, Cr, and Mn as third-period transition elements (TM) having an atomic radius similar to Fe. In this case, to prevent inferiority in magnetic shielding ability, it is preferable to include a content of 50 at. % or more of the ferromagnetic elements Fe, Co, and Ni. When a CCA containing three or more components selected from the group of alloy elements consisting of Fe, Co, Ni, V, Cr, and Mn is added instead of Fe in this manner, the stability of the second precipitate phase is improved due to the increase in constitutive entropy, which is desirable as it suppresses the precipitation of intermetallic compounds such as silicides. In this case as well, the additionally included compositions form particles of a second precipitate phase precipitated together with Fe and Si, and results similar to those in Cu-Fe-Si ternary alloys in a similar compositional range can be obtained.

[0093] In order to solve the above-mentioned problem, an electromagnetic shielding alloy proposed in one aspect of the present invention comprises: a first phase consisting of a Cu matrix; and a second precipitate phase rich in one or more ferromagnetic elements selected from Fe, Co, and Ni; wherein the second precipitate phase comprises spherical or fragmented dendritic precipitate particles.

[0094] In one embodiment, the second precipitate may further include Si.

[0095] In the present specification, the second precipitate rich in ferromagnetic elements may be understood as satisfying a total content of Fe, Co, and Ni among the metal elements included in the second precipitate of 50 at.% or more.

[0096] Specifically, the alloy may have a composition expressed by Formula 1.

[0097] [Equation 1]

[0098] Cu x TM 100-x-y Si y

[0099] In the above Equation 1,

[0100] TM necessarily includes one or more selected from Fe, Co, and Ni, and optionally includes one or more from Cr, Mn, V, Mg, Zn, Ta, and Bi, x is 51 to 94 wt. %, and y is 0.1 to 5 wt. %.

[0101] In one embodiment, the TM may contain a total content of Fe, Ni, and Co of 50 at.% or more. By satisfying a total content of the ferromagnetic elements of 50 at.% or more in the TM, the second precipitate phase may be rich in the ferromagnetic elements. Since the second precipitate phase maintains a precipitate phase rich in ferromagnetic (Fe, Co, Ni) elements, an alloy in which the second precipitate phase is evenly distributed may exhibit high magnetism. In the present invention, by controlling the second precipitate phase into spherical precipitate particles and dispersing them uniformly across the entire alloy region, an alloy having a high electromagnetic shielding effect can be manufactured.

[0102] The above composition is a composition in which one or more ferromagnetic elements selected from Fe, Co, and Ni combine with Si within a Cu matrix at room temperature to form spherical or fragmented dendritic precipitates within Cu. In the above composition, fragmented dendritic (FD) or spherical (S) precipitates with an equivalent diameter of 10 μm or less can be precipitated as a second precipitate, and thus an alloy with high electromagnetic shielding ability can be realized.

[0103] In the above embodiment, if Si is not added to the composition of the alloy, a second precipitate phase of columnar dendrites with an equivalent diameter exceeding 10 μm may be precipitated together. In this case, as described above, due to localized stress concentration during alloy processing, a problem may arise in which severe plastic deformation, which is mainly used for use as an electromagnetic shielding member, becomes difficult.

[0104] In some experimental examples of specific compositions described below, it can be observed that spherical precipitates are not evenly distributed but may form intensively in certain areas. In this case, the Fe-rich precipitates possessing electromagnetic shielding capabilities are not formed evenly, which may lead to a decline in the alloy's properties. Furthermore, in some experimental examples of specific compositions, precipitates may not be dispersed in a spherical shape but instead form columnar dendrites (CD). In this case as well, processing and molding the specimens become difficult, which may result in a decline in performance and applicability as an electromagnetic shielding material.

[0105] In the case of the composition of the black-filled region in FIG. 1, where x is 70 wt.% to 92 wt.% and y is 0.2 wt.% to 3.4 wt.%, a microstructure in which spherical (S) precipitated particles are uniformly dispersed is formed, which may be more desirable. Therefore, in this compositional region, an alloy having superior processability and electromagnetic shielding ability can be realized. The second precipitated phase in this composition may include spherical particles with a diameter of 5 μm or less or fragmented dendrites (FD) with an equivalent circular diameter of 5 μm or less. In this compositional region, the second precipitated phase may be directly precipitated during the casting process. Therefore, in this compositional region, no separate post-processing may be required after the second precipitated phase is formed.

[0106] According to one embodiment, the alloy may include spherical precipitates separated into a second precipitate phase. Through the SEM images described later, it can be confirmed that when the second precipitate phase is separated within the solubility gap, some of these are formed as dendrites and some of these are formed as spherical precipitates. In other embodiments, irregularly shaped particles may also be formed. If the second precipitate phase is precipitated in a columnar dendrite (CD) shape with an equivalent diameter of more than 10 μm, a problem may arise in that it becomes difficult to form and process it as an electromagnetic shielding member.

[0107]

[0108] According to one embodiment, TM in Formula 1 may be Fe. That is, the alloy is Cu x Fe 100-x-y Si y It has a composition expressed as, where x is 51 to 94 wt. % and y is 0.1 to 5 wt. %. The alloy is Cu x Fe 100-x-y Si y When having a composition expressed as such, it is possible to provide an alloy with excellent electromagnetic shielding performance and excellent price competitiveness.

[0109] When the above TM is Fe, the above second precipitated phase may include one or more phases among Fe solid solution, FeSi, Fe2Si, Fe3Si, and Fe5Si3.

[0110] In some embodiments of the present invention, the composition of the alloy may have a portion of the total content of Fe, Co, and Ni replaced with elements of Co, Ni, V, Cr, and Mn that facilitate the formation of a Complex Concentrated Alloy (CCA). In these embodiments as well, the shape control of the precipitate phase within the Cu matrix may be achieved to the intended level in a similar compositional range. Specifically, the types of elements constituting the TM may be three or more, and the three or more elements may constitute a Complex Concentrated Alloy (CCA).

[0111] When a Cu-TM-Si multicomponent alloy is manufactured, the three or more TM elements can form a second precipitate phase together with Si, and can be precipitated as a second precipitate phase while maintaining the CCA state without forming individual compounds such as silicide.

[0112] When the types of elements constituting the above TM are three or more, and the three or more elements constitute a complex supersolid solution alloy, the second precipitated phase may include one or more phases among a CCA solid solution with an FCC structure, (CCA)Si, (CCA)2Si, (CCA)3Si, and (CCA)5Si3.

[0113] The composition of the above complex over-solid solution alloy may have an equiatomic ratio or a non-equiatomic ratio.

[0114] According to one embodiment, the spherical precipitated particles may have a diameter of 5 μm or less. If the diameter exceeds 5 μm, homogeneous dispersion in the first phase may be difficult. The diameter of the spherical precipitated particles may be 0.1 μm or more.

[0115] According to one embodiment, when the TM includes one or more of Mg, Zn, Ta, and Bi, the total content of Mg, Zn, Ta, and Bi may be 5 wt.% or less relative to the total weight of the TM. These elements are expected to simultaneously promote nucleation and inhibit precipitate growth when a second precipitate phase is formed within the Cu matrix.

[0116] In the above examples, the metals other than Fe and Si in the Cu matrix may serve as dopants or inoculants introduced for a specific purpose.

[0117] A method for manufacturing an electromagnetic shielding alloy proposed in another aspect of the present invention comprises: a step of melting a Cu metal; a step of adding a metal element including one or more ferromagnetic elements selected from Fe, Co, and Ni and Si to the molten Cu metal; and a step of casting and cooling the molten alloy.

[0118] The step of cooling the alloy after casting may involve arc heating to a single-phase region greater than the solubility gap of the alloy, followed by solidification through drop casting and cooling of the copper mold to precipitate a second precipitate phase.

[0119] At this time, the metal elements may further include one or more elements selected from Cr, Mn, V, Mg, Zn, Ta, and Bi.

[0120] The ferromagnetic element, Si, and additional metal element added to the molten Cu metal can be added to the electromagnetic shielding alloy in an amount that satisfies the compositional formula described above.

[0121] According to one embodiment, the alloy may be an alloy according to one embodiment of the present invention described above.

[0122] According to one embodiment, after the step of casting the alloy, the method may further include the step of performing a post-processing step of a thermal-mechanical method.

[0123] However, the alloy casting method proposed in the present invention is not limited to the drop casting method after arc melting as described above, and any general alloy casting method that forms spherical precipitates containing Fe on a Cu matrix as described above may fall under the technical concept of the present invention.

[0124] An electromagnetic shielding member proposed in another aspect of the present invention may comprise an alloy according to one embodiment of the present invention; and a polymer resin.

[0125] In one embodiment of the present invention, the polymer resin may comprise one or more of a photocurable resin, a thermocurable resin, and a thermoplastic resin, and the polymer resin that can be introduced into the present invention is not specifically limited in its composition as long as it is a material that can be mixed with the alloy to form a member. The electromagnetic shielding member may be manufactured in the form of a film or a cable, for example, but the shape of the member is not specifically limited in the present invention.

[0126] The matters mentioned in the electromagnetic shielding alloy, the method for manufacturing the electromagnetic shielding alloy, and the electromagnetic shielding member of the present invention shall apply equally unless they contradict one another.

[0127] The alloys of all embodiments described below were prepared using an arc melting apparatus that has a purity of 99.9% or higher, a rapid cooling rate, and a high vacuum to minimize the effects of defects such as oxidation and porosity. Commercial casting methods capable of corresponding to this can all be applied to the manufacture of Cu-TM-Si-based casting alloys to be developed in this invention.

[0128] For example, it may be possible to manufacture the aforementioned alloy through various commercial casting processes, such as induction melting, which facilitates the production of alloys with a homogeneous microstructure; resistance heating, which enables precise temperature control; rapid solidification, which is advantageous for the formation of a complete solid solution; spark plasma sintering, which facilitates precise microstructure control and the production of parts of a desired shape; and hot isostatic pressing.

[0129] All embodiments described below were fabricated using only a simple casting process. However, commercial thermomechanical processing (TMT) methods for optimizing the mechanical and electromagnetic properties of the alloy can be applied to all Cu-TM-Si cast alloys proposed in this invention.

[0130] For example, processes such as hot working, which facilitates recrystallization and minimizes internal defects and stress by performing rolling, forging, or extrusion at high temperatures above 900°C, and rolling or wire drawing at room temperature to improve strength through work hardening can be applied. In addition, various commercial thermomechanical processing methods can be applied, such as cold working, which optimizes microstructure and mechanical properties in conjunction with stepwise strain control and subsequent heat treatment as needed; annealing and aging processes, which improve mechanical properties by removing internal stress and inducing a uniform distribution of fine precipitates in the temperature range between 300°C and 900°C; multi-stage thermomechanical processing, which forms a uniform microstructure through repetitive heat treatment and deformation processes; and severe plastic deformation (SPD) processes, which form ultrafine grains.

[0131] Hereinafter, experimental examples having each composition tested by the inventors of the present invention are described in detail along with images showing the results of phase precipitation observed on the surface and drawings showing the results of testing the crystal structure. The experimental examples described below are the results of the inventors preparing various alloys ranging from binary alloys to multi-component alloys and observing the crystal structure and the shape of the second precipitate phase appearing in each composition through X-ray diffraction analysis and scanning electron microscopy.

[0132] All of the following alloy samples of the examples and comparative examples were prepared by weighing each metal element by an appropriate weight according to the compositions listed in Tables 1 to 3 and then melting them together. Subsequently, the molten multi-component alloy was drop-cast and cooled to room temperature to precipitate a second precipitate phase. The degree of dispersion and the shape of the second precipitate phase were observed for the prepared alloy samples.

[0133] The experimental example samples presented in [Table 1] below may include not only samples included within the compositional range proposed in the embodiments of the present invention, but also comparative example samples of the control group that are not included. To elaborate, the sample compositions below are the results of observing the crystal structure and the particle shape of the second precipitate phase according to the composition while varying the content of other elements while fixing the Cu content at 90 wt.%. Depending on the particle shape of the second precipitate phase, columnar dendrites are indicated as CD (Columnar Dendrite), fragmented dendrites as FD (Fragmented Dendrite), and spherical particles as S (Spherical).

[0134] Sample composition Fe-Si element content (wt. %), remainder 90 wt. % Cu Crystal Structure 2 Comparison of Shapes of Precipitated Phase Particles Example 1 Fe10FCC+BCCCD Example 1 Fe8.33-Si1.67FCC+BCCS Example 2 Fe9.9-Si0.1FCC+BCCFD Example 3 Fe9.5-Si0.5FCC+BCCFD Example 4 Fe9.0-Si1.0FCC+BCCFD Example 5 Fe8.6-Si1.4FCC+BCCS Example 6 Fe8.4-Si1.6FCC+BCCS, FD Example 7 Fe8.3-Si1.7FCC+BCCS, FD Example 8 Fe8.2-Si1.8FCC+BCCS, FD Example 9 Fe8.1-Si1.9FCC+BCCS, FD Example 10 Fe8.0-Si2.0FCC+BCCS, FD Example 11 Fe7.9-Si2.1FCC+BCCS, FD Example 12 Fe7.7-Si2.3FCC+BCCS, FD Example 13 Fe7.2-Si2.8FCC+BCCS, FD Example 14 Fe6.7-Si3.4FCC+BCCFD, S Example 15 Fe6-Si4FCC+BCCFD Comparative Example 2 Fe4.6-Si5.4FCC+BCC+SilicideFD Comparative Example 3 Fe4-Si6FCC1+SilicideFD, CD Comparative Example 4 Fe3-Si7FCC1+SilicideCD

[0135] Comparative Example 1 is [Formula 1] Cu x TM 100-x-y Si y(In the case where TM=Fe) the alloy has an x ​​value of 10 wt.% and a y value of 0 wt.%, and Examples 1 to 15 and Comparative Examples 2 to 4 are compositions of alloys formed in the range of a y value of 0.1 wt.% to 7 wt.% according to one experimental example. Among these, Examples 1 to 15 are compositions of alloys formed in the range of a y value of 0.1 wt.% to 5 wt.%, and may be preferred embodiments having a microstructure composed of an FCC Cu matrix phase and an Fe-rich BCC precipitate phase in which the precipitation of silicide is suppressed. Furthermore, among these, Examples 1 and Examples 5 to 14 are compositions of alloys with a y value of 0.2 wt.% to 3.4 wt.%, and may be even more preferred embodiments having a microstructure in which a spherical (S) BCC Fe-rich precipitate phase is uniformly dispersed.

[0136] The examples and comparative examples presented in [Table 2] below are experimental results obtained by adding one or more of Co, Ni, V, Cr, and Mn to the Cu-Fe-Si ternary alloy of [Table 1] above. The examples and comparative examples presented in [Table 2] also consisted of 90 wt.% of a Cu base and 10 wt.% of other elements.

[0137] Sample composition based on total alloy 10 wt. Ratio of elements excluding Cu (at. %) occupied by % Crystal structure Shape of precipitated phase particles in the second Comparative Example 5 Fe33.34-Co33.33-Ni33.33FCC1+FCC2CD Comparative Example 6 Fe25-Co25-Ni25-Cr25FCC1+FCC2CD, Film at GB Comparative Example 7 Fe25-Co25-Ni25-Mn25FCC1+FCC2Irregular Comparative Example 8 Fe20-Co20-Ni20-Cr20-Mn20FCC1+FCC2CD, Irregular Example 16 Fe20-Co20-Ni20-Cr20-Si20FCC1+FCC2S, FD Example 17 Fe20-Co20-Ni20-Mn20-Si20FCC1+FCC2S Example 18Fe16.67-Co16.66-Ni16.66-Cr16.66-Mn16.66-Si16.66FCC1+FCC2FD

[0138] Through the experimental results of Comparative Examples 5 to 8, it was confirmed that when Si is not included, columnar dendrites (CD) or irregularly shaped particles larger than 10 μm are precipitated together as a second precipitate phase in Cu-CCA.

[0139] In the case of Cu-CCA-Si of Examples 16 to 18, Fe-rich second precipitates in the form of spherical particles (S) or fragmented dendrites (FD) were precipitated, and it was confirmed that the microstructure was formed similarly to the compositional range proposed in the examples of Table 1 for Cu-Fe-Si ternary alloys.

[0140] Meanwhile, FIGS. 4 to 9 are SEM images showing the microstructures of experimental example specimens prepared with their respective compositions according to the content proposed in the present invention. Some of these samples are example samples corresponding to the compositional range of the alloy proposed in the present invention, while some may be comparative example samples prepared for comparison, although they do not correspond to the compositional range of the alloy proposed in the present invention. Spherical precipitation or dendritic precipitation can be observed in the surface images of each sample.

[0141] Figure 4 shows the microstructures of Comparative Example 1, in which the second precipitate within the Cu matrix is ​​formed as (a) columnar dendrites (CD), and Example 1, in which it is formed as (b) spherical shapes, and the results of analysis using a backscattered electron (BSE) detector in a scanning electron microscope. To quantitatively evaluate the diameter of amorphous particles including spherical and fragmented dendrites, the analysis was performed using the Equivalent Circle Diameter (ECD), which is a value converted to the diameter of a circle having the same area as the actual area of ​​the particle. As shown in Figure 4, in Comparative Example 1, in which no Si was added, it can be confirmed that columnar dendrites (CD) with an equivalent circle diameter greater than 10 μm were precipitated as the main second precipitate. Meanwhile, in Example 1, it can be confirmed that the second precipitate, consisting of spherical shapes (S) with a diameter of 5 μm or less or fragmented dendrites (FD) with an equivalent circle diameter of 5 μm or less, was precipitated relatively uniformly.

[0142] FIG. 5 is an SEM image showing the shape of the Fe-rich second precipitate formed in the Cu matrix of (a) Example 4, (b) Example 5, (c) Example 6, (d) Example 8, (e) Example 11, and (f) Example 14. More specifically, in Examples 4 and 14, fragmented dendritic (FD) precipitates with an equivalent diameter of 10 μm or less are predominantly observed on the Cu matrix. In addition, in Examples 5 to 11, it can be confirmed that spherical precipitates (S) with an equivalent diameter of 5 μm or less are predominantly precipitated on the Cu matrix. Thus, Examples 5 to 11 are all alloys belonging to the black-filled region in FIG. 1, with an x ​​value of 70 wt.% to 92 wt.% and a y value of 0.2 wt.% to 3.4 wt.% in the composition proposed in one embodiment of the present invention.

[0143] Figure 6 shows Cu 90 Fe 10-y Si y This is a pseudo-binary phase diagram of a ternary alloy system. The equilibrium phase information according to temperature for the example compositions shown in FIG. 5 is shown within the figure. More specifically, Example 4 is included in the region where the Fe-rich second precipitate phase is formed first upon solidification. Examples 5 to 14 are included in the region where the Fe-rich second precipitate phase is formed after passing through the liquid-liquid phase separation region first upon solidification. Under the latter condition, if the solidification region after the liquid-liquid phase separation region is 150 K or lower, the spherical or fragmented dendritic second phase precipitation of the present invention is possible. Further details will be described later.

[0144] FIG. 7 is an SEM image showing the shape of the second precipitate phase formed in the Cu matrix in experimental examples (Comparative Examples 5 to 8, Examples 16 to 18) containing CCA (Concentrated Composition Alloy) with an equiatomic ratio in the Cu matrix. Through FIG. 7, the shapes of each second precipitate phase recorded in [Table 2] above can be confirmed.

[0145] Figure 8 shows the XRD analysis results of (a) Example 5, (b) Example 8, and (c) Comparative Example 2. In all three examples, Cu peaks of the matrix phase FCC structure and Fe peaks of the precipitate phase BCC structure were commonly observed, while in Comparative Example 2, an M(Cu-Fe)-Si intermetallic compound diffraction pattern was additionally confirmed.

[0146] Figure 9 shows Cu x Fe 99-x Si 1.0 and Cu x Fe 98.6-x Si 1.4The solidification behavior and microstructural differences upon cooling from the liquid phase, as well as the final microstructure, of (a) Example 4 and (b) Example 5, which are compositions on the pseudo-binary phase diagram of a ternary alloy system, are shown. More specifically, regarding the solidification behavior of Example 4, when solidifying in a single mixed liquid phase of a Cu-Fe-Si ternary alloy, Fe-rich precipitate phase nucleates first. Subsequently, due to diffusion behavior caused by the compositional difference between the precipitate phase and the liquid phase, preferential growth occurs on specific planes, resulting in the preferential growth of Fe-rich precipitate phases in a dendritic form. Afterward, the Cu-rich liquid phase region solidifies, and solidification concludes with the two phases coexisting. However, in Example 4, which corresponds to the compositional region of the present invention, the solidification region in which the second precipitate phase occurs is short, so it precipitates mainly in the form of fragmented dendrites (FD). In the solidification behavior of Example 5, when the Cu-Fe-Si ternary alloy solidifies in a single mixed liquid phase, it first reaches a liquid phase (Cu)-liquid phase (Fe) phase separation region where compositional separation occurs, and subsequently, the liquid phase (Fe) solidifies first. Since the composition in the liquid phase (Cu)-liquid phase (Fe) separation region is already separated to a composition close to equilibrium, and a stable interface with a large compositional deviation between the Cu-Fe liquid phases is formed, dendritic growth is suppressed, and spherical Fe-rich precipitates solidify first. At this time, if the liquid phase separation region is passed through relatively briefly, the growth of spherical precipitates with an equivalent diameter of 10 μm or less is suppressed. Subsequently, the Cu-rich liquid region solidifies, and the process concludes with the two phases coexisting.

[0147] FIG. 10 is △T (liquid temperature (T) of Examples 4, 5, 6, 8, 11, 12, 14, and 15. L ) - Fe precipitate formation temperature (T Fe )) was shown. In these embodiments, the liquid phase temperature (T L ) is the liquid phase separation temperature (T LL ) is. SEM images of the embodiments in FIG. 6 and Cu in FIG. 7. 90 Fe 10-ySi y Based on the pseudo-binary phase diagram of the ternary alloy system, the correlation between △T and microstructure according to y content was confirmed. When the liquid-liquid phase separation region is not passed during solidification, Fe-rich secondary precipitates are predominantly formed, and FD-shaped secondary precipitates with an equivalent diameter of 10 μm or less are formed (Examples 1 to 4). In addition, it was confirmed that spherical Fe-rich secondary precipitates can be predominantly formed in a compositional range where the liquid-liquid phase separation region is passed and △T satisfies 150 K or less (Examples 5 to 14). In contrast, when passing through the liquid-liquid phase separation region and having a △T range greater than 150 K and within 200 K, a second precipitate of the FD shape is formed again (Example 15), and when having a △T range greater than 200 K, it was confirmed that coarse Fe second precipitates of columnar dendritic (CD) shape are predominantly formed (Comparative Examples 2 to 4).

[0148] While [Table 2] above shows the results of confirming the difference between Cu-CCA multi-component alloys with equivalent elemental ratios and Cu-(CCA+Si) multi-component alloys by comparing comparative examples and examples, [Table 3] below presents examples examining cases where CCA is composed in non-equiatomic ratios, unlike cases where it is composed in equivalent elemental ratios. The examples presented in [Table 3] also consist of 90 wt.% Cu base and 10 wt.% other elements.

[0149] It was confirmed that the examples in [Table 3] also exhibited a microstructure of the precipitated phase similar to the case where only Fe and Si were included in the Cu matrix, without significant difference from the case where they were composed with the equivalent elemental ratios presented in [Table 2] above.

[0150] Sample Composition Ratio of elements excluding Cu (at. %) accounting for 10 wt. % based on the total alloy Crystal Structure Shape of 2nd precipitate phase particles Example 19 Fe45-Co20-Ni20-Mn10-Si5FCC1+FCC2S, FD Example 20 Fe45-Co20-Ni20-Cr10-Si5FCC1+FCC2S, FD Example 21 Fe35-Co24-Ni24-Mn12-Si5FCC1+FCC2S, FD Example 22 Fe35-Co22-Ni22-Mn11-Si10FCC1+FCC2(+Silicide)S, FD Example 23 Fe35-Co20-Ni20-Mn10-Si15FCC1+FCC2+SilicideS Example 24Fe40-Co22-Ni22-Mn11-Si5FCC1+FCC2S, FD Example 25Fe40-Co20-Ni20-Mn10-Si10FCC1+FCC2(+Silicide)S, FD Example 26Fe40-Co18-Ni18-Mn9-Si15FCC1+FCC2+SilicideS Example 27Fe45-Co20-Ni20-Mn10-Si5FCC1+FCC2S Example 28Fe45-Co18-Ni18-Mn9-Si10FCC1+FCC2(+Silicide)S, FD Example 29Fe45-Co16-Ni16-Mn8-Si15FCC1+FCC2+SilicideS Example 30Fe50-Co18-Ni18-Mn9-Si5FCC1+FCC2S, FD Example 31Fe50-Co16-Ni16-Mn8-Si10FCC1+FCC2(+Silicide)S, FD Example 32Fe50-Co14-Ni14-Mn7-Si15FCC1+FCC2+SilicideS Example 33Fe55-Co16-Ni16-Mn8-Si5FCC1+FCC2S, FD Example 34Fe55-Co14-Ni14-Mn7-Si10FCC1+FCC2(+Silicide)S, FD Example 35Fe55-Co12-Ni12-Mn6-Si15FCC1+FCC2+SilicideS

[0151] Figure 11 is a graph showing (a) the effect of each element on the nucleation behavior affecting grain size and (b) the relative columnar growth restriction factor (G) for each element added to the Cu matrix as a criterion for additionally adding a third element to control the nucleation and growth rate of the second precipitate phase in Cu-Fe-Si or Cu-CCA-Si alloys. Specifically, Figure 11 is excerpted from the document 'Grain refinement of DHP copper by elemental additions' published by Ballart, M. J. et al. in the International Journal of Cast Metals Research, 28(4), pp. 248-256. Through Figure 11(a), elements that promote the nucleation of the precipitate phase in the Cu matrix were examined. For example, elements such as Be, Mg, P, S, Ca, V, Mn, Zn, Sr, As, Se, Zr, Mo, In, Sn, Sb, Te, Ta, Tl, Pb, and Bi, which are shown to have grain sizes below the dotted line (650 μm) region, can be expected to promote nucleation of a second precipitate phase when additionally added to a Cu matrix. That is, the addition of these elements can be expected to have the effect of reducing the Cu grain size and delaying the growth of the second precipitate phase.

[0152] Meanwhile, through Fig. 11(b), elements capable of relatively inhibiting the growth of the second phase were examined based on the relative columnar growth restriction factor (G) representing the inhibitory power of the columnar microstructure growth for each element. For example, elements such as Li, Mg, Al, Fe, Mn, Cr, V, Zn, Ce, Ba, W, Ta, Au, and Bi, which are elements below the dotted line (G value is 12), can be expected to inhibit the growth of columnar crystals in the Cu matrix and delay the growth of the second precipitated phase.

[0153] Elements located below the dotted line in both graphs of Fig. 11 indicate that they can simultaneously promote nucleation and inhibit growth, and this applies to the elements Mg, V, Mn, Zn, Ta, and Bi. Among these elements, excluding V and Mn which are FCC stabilizing elements, Mg, Zn, Ta, and Bi are not desirable when added in amounts exceeding 5 wt.% as they form intermetallic compounds.

[0154] Based on this analysis, the inventors prepared the composition of Example 27 by additionally adding Mn, an element capable of simultaneously performing two roles of promoting nucleation and inhibiting growth, to the Cu-TM-Si alloy, and observed the second precipitate phase through SEM in the same way as the examples in [Table 1] and [Table 2] above.

[0155] The composition of Example 27 is Cu, containing Fe, Co, Ni, and Si in a Cu base of 90 wt. % under the same conditions, as well as 10 at. % Mn added relative to the elements excluding Cu. 90wt.% (Fe 0.45 Co 0.2 Ni 0.2 Mn 0.1 Si 0.05 ) 10wt.% It was designed to have the composition of.

[0156] FIG. 12 is a low-magnification SEM image observing the shape of the second precipitate phase of Example 27.

[0157] In addition, FIG. 13 is a high-magnification SEM image of Example 27 and an SEM-EDS elemental mapping image that can identify the constituent elements of the precipitate formed on the Cu matrix for the microstructure.

[0158] Through the images in Figures 12 and 13, it was confirmed that when a small amount of Mn is added, a second precipitate phase of more uniform and fine spherical particles is precipitated, just as predicted in the design. In addition, it was confirmed that the precipitate phase within the Cu matrix consists of Fe, Co, Ni, and Si, and that the additionally added Mn element performed its role as an inoculant as intended.

[0159] Figure 14 is an elemental line scan image from SEM-EDS showing the elemental distribution of the phase precipitated in the Cu matrix of Example 30. EDS elemental line scan analysis was performed in the direction indicated by the arrow within the SEM microstructure in Figure 14, and as can be seen from the line scan profile below Figure 14, the concentration of each metal included in the precipitated phase contrasting with the Cu matrix can be confirmed. In addition, it can be confirmed that in the precipitated phase region, the proportion of Cu composition decreases, while the concentrations of Fe, Co, Ni, etc., relatively increase, forming a CCA solid solution.

[0160] The foregoing description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are intended to explain, not limit, the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by these embodiments. The scope of protection of the present invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention.

Claims

1. A first phase composed of a Cu matrix; and a second precipitated phase rich in one or more ferromagnetic elements selected from Fe, Co, and Ni; comprising The above second precipitate phase comprises spherical or fragmented dendritic precipitates, an electromagnetic shielding alloy.

2. In Paragraph 1, The above second precipitate phase is an electromagnetic shielding alloy that further contains Si.

3. In Paragraph 1, The above alloy is an electromagnetic shielding alloy having a composition expressed by Formula 1: [Equation 1] The x ™ 100-x-y Be y In the above Equation 1, TM must include at least one selected from Fe, Co, and Ni, and optionally includes at least one selected from Cr, Mn, V, Mg, Zn, Ta, and Bi, and x is 51 to 94 wt. % and y is 0.1 to 5 wt. %.

4. In Paragraph 3, The above TM is an electromagnetic shielding alloy containing a total content of Fe, Ni, and Co of 50 at. % or more.

5. In Paragraph 3, The above TM is an electromagnetic shielding alloy in which Fe.

6. In Paragraph 5, The above second precipitated phase comprises one or more phases selected from Fe solid solution, FeSi, Fe2Si, Fe3Si, and Fe5Si3, for an electromagnetic shielding alloy.

7. In Paragraph 3, An electromagnetic shielding alloy in which x is 70 to 92 wt. % and y is 0.2 to 3.4 wt. %.

8. In Paragraph 3, An electromagnetic shielding alloy in which the types of elements constituting the above TM are three or more, and the three or more elements constitute a Complex Concentrated Alloy (CCA).

9. In Paragraph 8, The above second precipitated phase comprises one or more phases selected from FCC CCA solid solution, (CCA)Si, (CCA)2Si, (CCA)3Si, and (CCA)5Si3, for an electromagnetic shielding alloy.

10. In Paragraph 3, If the above TM includes one or more of Mg, Zn, Ta, and Bi, An electromagnetic shielding alloy having a total content of Mg, Zn, Ta, and Bi of 5 wt.% or less relative to the total weight of TM.

11. In Paragraph 1, The above alloy is an electromagnetic shielding alloy obtained by performing only a casting process.

12. In Paragraph 1, The above second precipitate phase is an electromagnetic shielding alloy that does not contain columnar dendrite precipitates with an equivalent diameter of more than 10 μm.

13. In Paragraph 1, The above-mentioned second precipitate phase precipitate particles have an equivalent circular diameter of 10 μm or less, and is an electromagnetic shielding alloy.

14. In Paragraph 7, △T(=liquid-liquid phase separation temperature(T L ) - Fe precipitate formation temperature (T Fe Electromagnetic shielding alloy having a value of 150 K or less.

15. Step of melting Cu metal; A step of adding one or more ferromagnetic elements selected from Fe, Co, and Ni and metal elements including Si to the molten Cu metal; and A method for manufacturing an electromagnetic shielding alloy comprising the step of casting and then cooling the molten alloy.

16. In Paragraph 15, A method for manufacturing an electromagnetic shielding alloy, wherein the above metal elements further include one or more elements selected from Cr, Mn, V, Mg, Zn, Ta, and Bi.

17. In Paragraph 15, The manufactured alloy is, A first phase composed of a Cu matrix; and a second precipitated phase rich in one or more ferromagnetic elements selected from Fe, Co, and Ni; comprising A method for manufacturing an electromagnetic shielding alloy, wherein the second precipitate phase comprises spherical or fragmented dendritic precipitates.

18. In Paragraph 15, The step of cooling the molten alloy after casting is Casting is performed in a single liquid phase region greater than the solubility gap of the above alloy, and △T (=liquid-liquid phase separation temperature (T L ) - Fe precipitate formation temperature (T Fe A method for manufacturing an electromagnetic shielding alloy, wherein the alloy is cooled by passing through a solubility gap to satisfy a solubility of 150 K or less.

19. In Paragraph 15, After the step of cooling the molten alloy after casting, The step of performing a post-processing step using a thermal-mechanical processing (TMT) method; further comprising Method for manufacturing an electromagnetic shielding alloy.

20. An alloy of any one of claims 1 to 14; and Electromagnetic shielding member comprising a polymer resin.

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