A cobalt-based amorphous soft magnetic alloy material, its preparation, and a composite microwave absorbing structure based on the soft magnetic alloy.

Abstract

This invention discloses a cobalt-based amorphous soft magnetic alloy material, its preparation, and a composite microwave absorbing structure based on the soft magnetic alloy. Alloy material composition: Co a Fe b Ni c Si d B e Cr f Where 60≤a≤70, 2≤b≤6, 0.5≤c≤5, 10≤d≤20, 10≤e≤20, 0.5≤f≤5, a+b+c+d+e+f=100, the alloy material possesses low saturation magnetic induction, low coercivity, and high initial permeability, while also exhibiting excellent corrosion resistance and oxidation resistance. The composite absorbing structure obtained using the amorphous soft magnetic alloy material of this invention as the frequency-selective surface is simple in structure, has a simple frequency-selective surface pattern, and low manufacturing cost; it has a low total thickness, significantly improved effective absorption bandwidth, and combines the characteristics of being thin, light, and having wideband absorption, which is of great significance for promoting the development of thin, light, and wideband absorbing materials.

Description

Technical Field

[0001] This invention relates to the field of amorphous soft magnetic alloy materials and composite microwave absorbing structures, specifically to a cobalt-based amorphous soft magnetic alloy material, its preparation, and a composite microwave absorbing structure based on the soft magnetic alloy. Background Technology

[0002] With the advancement of communication and artificial intelligence technologies, the electromagnetic radiation problem generated by electronic devices has become increasingly serious, making the research of microwave absorbing materials crucial. Microwave absorbing materials can absorb electromagnetic waves and have wide applications in both military and civilian fields. Militarily, they are used for radar stealth and electromagnetic pulse protection to improve the battlefield survivability of weapons and equipment and protect personnel and equipment from radiation. In civilian applications, microwave absorbing materials are used to protect against electromagnetic radiation pollution and shield wireless communication equipment. As wireless communication technology continues to advance, the potential hazards of electromagnetic radiation increase, thus the research and development of microwave absorbing materials is receiving increasing attention.

[0003] However, traditional absorbing materials usually require a thicker absorption layer to achieve efficient absorption, resulting in greater material thickness and weight. In addition, traditional absorbing materials typically have a broad absorption range of electromagnetic waves within a certain frequency range, making it difficult to achieve selective absorption of specific frequencies, and thus they are generally difficult to apply in practical applications.

[0004] Therefore, frequency-selective surface (FSS) absorbing materials offer advantages over traditional absorbing materials, including thinner and lighter weight, stronger frequency selectivity, better thermal stability, and multifunctionality. These advantages make FSS absorbing materials promising for applications in communications, radar, and stealth technology. Among these, amorphous soft magnetic materials possess unique physical and chemical properties, such as high permeability, high strength, lightweight, corrosion resistance, flexibility, and ductility. These properties enable amorphous soft magnetic materials to play a crucial role in the field of electromagnetic wave absorption, facilitating the transition from traditional absorbing materials to novel FSS absorbing materials and bringing new possibilities to electromagnetic wave absorption and stealth technologies.

[0005] Chinese patent document CN113782975A discloses a composite material with deformed cross-shaped and square-ring fractal topological patterns. The thickness of this absorbing material reaches 10 mm, and the absorption bandwidth is approximately 10 GHz. Chinese patent document CN117578091A discloses a miniaturized frequency-selective surface composite absorbing device with a total absorbing material thickness of 7.05 mm or more and an absorption bandwidth potentially reaching 16 GHz.

[0006] Chinese patent document CN117748157A discloses a low-frequency bandwidth extended reconfigurable frequency selective surface composite absorbing device with a dipole array pattern. The total absorbing material thickness is between 5.025-40.8 mm, and the absorption bandwidth covers 6.0 GHz. Chinese patent document CN209843961U discloses a frequency selective surface pattern consisting of a double-ring metal patch, with a total absorbing material thickness of 6.75 mm and an absorption bandwidth of 14.2 GHz.

[0007] The aforementioned patents have improved the absorption performance of composite absorbing materials to varying degrees through frequency-selective surface design. However, these materials cannot simultaneously possess the comprehensive properties of being lightweight, thin, broadband, and easy to process, making it difficult to fabricate frequency-selective surface composite absorbing materials with broad applicability. Therefore, developing a frequency-selective surface composite absorbing material that combines lightweight, thinness, broadband, and simple processing is of great significance for promoting the development of frequency-selective surface substrates and the widespread application of cobalt-based amorphous soft magnetic alloy materials. Summary of the Invention

[0008] This invention addresses the poor overall performance of amorphous soft magnetic alloy materials and the difficulty of existing composite absorbing materials in simultaneously achieving thinness, wide bandwidth, and simple processing. It provides a cobalt-based amorphous soft magnetic alloy material, and uses this soft magnetic alloy material as a frequency selective surface to prepare a composite absorbing structure that has the advantages of being thin and having a significantly broadened absorption bandwidth.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A cobalt-based amorphous soft magnetic alloy material, wherein the composition of the cobalt-based amorphous soft magnetic alloy material has the following expression: Co a Fe b Ni c Si d B e Cr f In the formula, a, b, c, d, e, and f represent the atomic percentages of the corresponding components, where 60≤a≤70, 2≤b≤6, 0.5≤c≤5, 10≤d≤20, 10≤e≤20, 0.5≤f≤5, and a+b+c+d+e+f=100.

[0011] This invention is based on CoFeSiB material. A small amount of Ni is used to improve the soft magnetic properties of the material, and a small amount of transition metal is added to improve the corrosion resistance and physical properties. However, the addition of transition metal leads to a decrease in the permeability of some parts of the material and a decrease in the ability to form amorphous materials. Different elements have different effects on different properties of the material, and they also influence each other. The inventors found that the amorphous soft magnetic alloy with the above composition can have low saturation magnetic induction, low coercivity, and high initial permeability, while also having excellent corrosion resistance and oxidation resistance.

[0012] In some embodiments, the atomic percentage of Co in the cobalt-based amorphous soft magnetic alloy material is 60 ≤ a ≤ 68. Values ​​such as 60.5, 61, 61.5, 62, 62.5, 63, 63.5, 64, 64.5, 65, 65.5, 66, 66.5, 67, 67.5, or any value between them are preferred in some embodiments; more preferably, 62 ≤ a ≤ 67.5; further preferably, 63 ≤ a ≤ 67; and even more preferably, 64 ≤ a ≤ 66.5. The cobalt-based amorphous alloy has lower saturation magnetic induction and loss, and higher permeability at high frequencies, thus it is easier to saturate, has a high rectangularity ratio, and good high-frequency magnetic properties.

[0013] In some embodiments, the atomic percentage of Fe in the cobalt-based amorphous soft magnetic alloy material is 3 ≤ b ≤ 5. Values ​​such as 3.25, 3.5, 3.75, 4, 4.25, 4.5, 4.75, or any value between them are preferred in some embodiments; more preferably, 3.5 ≤ b ≤ 4.5; and even more preferably, 3 ≤ b ≤ 4. An appropriate iron content can reduce the coercivity of the amorphous alloy, increase its permeability and saturation magnetic induction, thereby improving its soft magnetic properties.

[0014] In some embodiments, the atomic percentage of Ni in the cobalt-based amorphous soft magnetic alloy material is 1 ≤ c ≤ 3. Values ​​such as 1.2, 1.25, 1.4, 1.5, 1.6, 1.75, 1.8, 2, 2.2, 2.4, 2.5, 2.6, 2.8, or any value between them are preferred in some embodiments; more preferably, 1.5 ≤ c ≤ 2.5; and even more preferably, 1 ≤ c ≤ 2. The addition of Ni can reduce the saturation magnetic induction intensity of the material to a certain extent, reducing the vacuum requirements for sprayed strips and the oxidation phenomenon caused by vacuum during heat treatment. However, the addition of this precious metal also increases the cost of raw materials.

[0015] In some embodiments, the atomic percentage of Si in the cobalt-based amorphous soft magnetic alloy material is 14 ≤ d ≤ 17. Values ​​such as 14.25, 14.5, 14.75, 15, 15.25, 15.5, 15.75, 16, 16.25, 16.5, 16.75, or any value between them are preferred in some embodiments; more preferably, 14.5 ≤ d ≤ 16.5; even more preferably, 15 ≤ d ≤ 16. Si can lower the melting point of the amorphous alloy, thus making it easier to form an amorphous structure during rapid cooling or rapid solidification. Furthermore, Si can change the viscosity of the alloy, further promoting amorphous formation and improving the alloy's amorphous forming ability.

[0016] In some embodiments, the atomic percentage of B in the cobalt-based amorphous soft magnetic alloy material is 10 ≤ e ≤ 15. Values ​​such as 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, or any value between them are preferred in some embodiments; preferably, 10 ≤ d ≤ 14.

[0017] In some embodiments, the atomic percentage of Cr in the cobalt-based amorphous soft magnetic alloy material is 0.5 ≤ f ≤ 3.5, such as 0.75, 1, 1.25, 1.75, 2, 2.25, 2.5, 2.75, 3, 3.25, or any value between them;

[0018] In this invention, a small amount of transition metal is used to improve the corrosion resistance of the material, making it suitable for a wider range of application environments. In some embodiments, the atomic percentage of Cr in the cobalt-based amorphous soft magnetic alloy material is 0.5 ≤ f ≤ 3, preferably 0.5 ≤ f ≤ 2. Within this range, the material exhibits good soft magnetic properties and strong overall amorphous forming ability. More preferably, it is 0.155 ≤ f ≤ 1.5.

[0019] In some embodiments, the total atomic percentage of Co and Fe in the cobalt-based amorphous soft magnetic alloy material is 65 ≤ a + b ≤ 70.

[0020] Compared to other elements, the addition of Cr gives the alloy material a better amorphous forming ability, a zero magnetostriction coefficient, excellent soft magnetic properties at high temperatures, and improved corrosion resistance.

[0021] In some embodiments, the purity of the Fe, Co, Ni, B, Si, and Cr raw materials is all above 99 wt.%. Preferably, the purity of all raw materials is above 99.5 wt.%.

[0022] The cobalt-based amorphous soft magnetic alloy material of this invention has the advantages of low saturation magnetic induction, low coercivity, high initial permeability and high rectangularity ratio, and has excellent soft magnetic properties.

[0023] The present invention also provides a method for preparing the cobalt-based amorphous soft magnetic alloy material, comprising the following steps: Step 1, weighing each element raw material according to the alloy composition and melting it into a master alloy ingot; Step 2, making the master alloy ingot into an amorphous soft magnetic alloy strip.

[0024] In some embodiments, step 1, when melting the master alloy ingot, includes the following steps: placing the weighed alloy raw material in a melting device and melting it under an inert atmosphere; holding the melted material at a temperature of 5-20 minutes, and then pouring the molten alloy ingot into a prepared copper mold and cooling it for more than 30 minutes to obtain the master alloy ingot.

[0025] The melting method for the aforementioned pure metals is arbitrary; for example, it may involve melting the metal by high-frequency heating after evacuating a chamber. Furthermore, the master alloy and the final soft magnetic alloy typically have the same composition.

[0026] In some embodiments, the raw materials are heated to melt them, resulting in molten metal (metal melt). There are no particular limitations on the temperature of the molten metal, as long as it is sufficient to melt all the raw materials, for example, 1300–1500°C.

[0027] Preferably, the smelting process is carried out 1-3 times to ensure that the components in each alloy ingot are evenly distributed.

[0028] In some embodiments, the preparation of amorphous soft magnetic alloy strip in step 2 includes, but is not limited to, at least one of the following: single-roll rapid quenching method, vacuum spray casting method, and medium-frequency induction melting method;

[0029] Preferably, the amorphous soft magnetic alloy strip is prepared by single-roll rapid quenching in step 2.

[0030] In this invention, the "single-roller rapid quenching method" refers to melting an ingot and pouring it onto the surface of a rotating water-cooled copper roller, which is then rapidly cooled to obtain a thin strip in an amorphous to microcrystalline state. The preparation process involves using a high-speed rotating roller to rapidly cool the molten liquid column into a thin strip.

[0031] In some embodiments, when the method for preparing the amorphous soft magnetic alloy strip in step 2 is a single-roll rapid quenching method, the process parameters of the single-roll rapid quenching method are: spray pressure of 0.01-0.03 MPa and copper roller rotation speed of 3000-5000 r / min. In some embodiments, the preferred process parameters of the single-roll rapid quenching method are: spray pressure of 0.01-0.03 MPa and copper roller rotation speed of 3500-4500 r / min.

[0032] Preferably, the process parameters for the single-roller rapid quenching method are: spray pressure of 0.02 MPa and copper roller rotation speed of 4000 r / min.

[0033] In some embodiments, the preparation of amorphous soft magnetic alloy strip by single-roll rapid quenching specifically includes the following steps: crushing the master alloy ingot and placing it in a quartz tube with a nozzle at the bottom; placing the quartz tube into a strip spinning machine to remelt the alloy ingot therein, and using the single-roll rapid quenching method to prepare continuous alloy amorphous strip.

[0034] The present invention also provides the application of the cobalt-based amorphous soft magnetic alloy material as a frequency selective surface layer material in a composite absorbing device.

[0035] This invention also provides a composite absorbing structure based on an amorphous soft magnetic alloy frequency selective surface. The composite absorbing structure comprises, from top to bottom, a first dielectric substrate layer, a frequency selective surface layer, and a second dielectric substrate layer. The frequency selective surface layer is made of the aforementioned cobalt-based amorphous soft magnetic alloy material. All layers are bonded together with adhesive.

[0036] There are relatively few reports on the use of cobalt-based amorphous soft magnetic magnetic materials as frequency selective surface materials in the prior art. The cobalt-based amorphous soft magnetic alloy of the present invention is used to prepare frequency selective surface layers. Under the premise of ultra-thin thickness and simple pattern, it has low processing difficulty, good forming performance, can achieve extremely high wave absorption performance, and has a wide effective absorption bandwidth, making it suitable for space-constrained occasions.

[0037] The frequency selection surface layer has a thickness of 0.02-0.05mm and includes multiple FSS units arranged in a row and column period of 10-90mm. The FSS units are equal-length cross patterns with a spacing of 45-60mm.

[0038] The cross pattern has an arm length of 30-80mm and an arm width of 15-25mm.

[0039] Preferably, the thickness of the first dielectric substrate layer is 1-2 mm, the real part of the complex dielectric constant ε' is 5.5-7.5, the imaginary part of the complex dielectric constant ε” is 0.1-1, the real part of the complex permeability μ' is 2.3-3.1, the imaginary part of the complex permeability μ” is 0.4-0.7, and the loss factor is 0.03-0.13.

[0040] Preferably, the thickness of the second dielectric substrate layer is 1-2 mm, the real part of the complex dielectric constant ε' is 15.5-17, the imaginary part of the complex dielectric constant ε” is 0.2-0.4, the real part of the complex permeability μ' is 3.1-4.3, the imaginary part of the complex permeability μ” is 0.6-1.9, and the loss factor is 0.02-0.03.

[0041] The first dielectric substrate layer is made of one or more of nickel-zinc ferrite, carbon fiber, and carbonyl iron, mixed with one or more of silicone, epoxy resin, and polyurethane.

[0042] The material of the second dielectric substrate layer includes one or more of nickel-zinc ferrite, carbon fiber, and carbonyl iron, which are mixed with one or more of silicone, epoxy resin, and polyurethane.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) The cobalt-based amorphous soft magnetic alloy material with the specific composition of the present invention has excellent soft magnetic properties such as low saturation magnetic induction intensity, low coercivity and high initial permeability. It still maintains high amorphous formation ability without the addition of P element, and has excellent comprehensive performance.

[0045] (2) The cobalt-based amorphous soft magnetic alloy material of the present invention also has good corrosion resistance and long-term stability, is suitable for a variety of harsh environments, and has a wide range of adaptability.

[0046] (3) The cobalt-based amorphous soft magnetic alloy material of the present invention does not contain rare earth metal elements and volatile elements, is inexpensive and has stable performance; it also does not contain harmful substances such as cadmium, lead and mercury, and is friendly to human health and the environment.

[0047] (4) The cobalt-based amorphous soft magnetic alloy material in this invention is used to prepare frequency selective surfaces. The resulting composite absorbing device has a simple structure, a simple frequency selective surface pattern, and low manufacturing cost. It has a low total thickness and a significantly improved effective absorption bandwidth. It also has the characteristics of being thin, light and wideband absorption, which is of great significance for promoting the development of thin, light and wideband absorbing materials. Attached Figure Description

[0048] Figure 1 The XRD diffraction patterns are those of the cobalt-based amorphous alloy materials in Examples 1, 2, 3 and Comparative Example 1.

[0049] Figure 2 The curves showing the saturation magnetic induction intensity changes of the cobalt-based amorphous alloy materials prepared in Examples 1, 2, 3 and Comparative Example 1 are shown.

[0050] Figure 3 Electrochemical curves of the cobalt-based amorphous alloy materials prepared in Examples 1, 2, 3 and Comparative Example 1.

[0051] Figure 4 This is a schematic diagram of the modeling of the composite absorbing structures based on frequency-selective surfaces prepared in Examples 4-13 and Comparative Examples 2-3.

[0052] Figure 5 The graph shows the variation of reflection loss with frequency for Examples 4-13 and Comparative Examples 2-3.

[0053] Figure 6 This is a schematic diagram of the composite absorbing device prepared for an application example.

[0054] Figure 7 The diagram shows the absorption performance of the composite absorbing device as an application example. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should be covered within the protection scope of this invention.

[0056] Before further describing specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the respective manufacturers.

[0057] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. In addition to the specific methods, apparatus, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description of this invention, any prior art methods, apparatus, and materials similar to or equivalent to those described, apparatus, and materials in the embodiments of this invention may be used to implement the present invention.

[0058] This invention provides the following specific embodiments and all possible combinations thereof. For the sake of brevity, this application only describes a few representative components to represent all possible combinations of the described technical solutions.

[0059] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application's specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0060] As used herein, the terms "and / or," "or / and," and "and / or" encompass any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected using at least two conjunctions selected from "and / or," "or / and," and "and / or," it should be understood that, in this application, the technical solution undoubtedly includes solutions connected by "logical AND," and also undoubtedly includes solutions connected by "logical OR."

[0061] For example, "A and / or B" includes three parallel solutions: A, B, and A+B. Another example is the technical solution "A, and / or, B, and / or, C, and / or, D," which includes any one of A, B, C, and D (i.e., all connected by "logical OR"), any and all combinations of A, B, C, and D, including combinations of any two or three of A, B, C, and D, and combinations of all four of A, B, C, and D (i.e., all connected by "logical AND").

[0062] The terms “containing,” “comprising,” and “including” as used in this invention are synonyms and are inclusive or open-ended, not excluding additional, uncited members, elements, or method steps.

[0063] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0064] In this invention, terms such as "preferred," "better," "more suitable," and "ideal" merely describe implementation methods or embodiments that yield better results and should be understood not to limit the scope of protection of this invention. If multiple "preferred" terms appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "preferred" term shall be independent.

[0065] In this invention, terms such as "further," "even more," and "particularly" are used for descriptive purposes and to indicate differences in content, but should not be construed as limiting the scope of protection of this invention.

[0066] All raw materials used in the following specific implementation methods were purchased from the market.

[0067] Example 1

[0068] In this embodiment, the molecular formula of the cobalt-based amorphous soft magnetic alloy material is Co. 65.07 Fe 3.94 Ni 0.99 Si 15B 14 The specific preparation method of Cr1 alloy material is as follows:

[0069] Step 1: Mix raw materials Co, Fe, Ni, Si, B, and Cr with a purity greater than 99.5% according to the compositional relationship Co 65.07 Fe 3.94 Ni 0.99 Si 15 B 14 Cr1 is used for batching, and the weighing error is controlled within 0.0005g;

[0070] Step 2: Place the pre-prepared raw materials into a clean alumina crucible, put it into an induction melting furnace, and evacuate to below -0.002 Pa under an argon atmosphere. After melting, hold at the temperature for more than 10 minutes, then pour the molten alloy into a copper mold and cool in the furnace for 25 minutes to obtain a homogeneous master alloy ingot.

[0071] Step 3: After crushing the master alloy ingot obtained in Step 2, load it into a quartz tube with a nozzle of approximately 60mm. Adjust the distance between the tube opening and the roller surface to approximately 0.25mm, then evacuate to less than 0.02Pa. Adjust the pressure difference between the inside and outside of the quartz tube to 0.02MPa, and use a single-roller rapid quenching spinning process under an argon protective atmosphere, spinning the strip at a speed of 40m / s. That is, set the copper roller speed to 4000r / min and connect the heating current. When the solenoid heats and melts the master alloy ingot until it is completely melted and a white light and shaking phenomenon is observed, turn off the heating current and press the spray button simultaneously to obtain a continuous amorphous alloy strip. The strip width is 60mm and the thickness is 30μm.

[0072] Example 2

[0073] In this embodiment, the molecular formula of the cobalt-based amorphous soft magnetic alloy material is Co. 64.14 Fe 3.89 Ni 0.97 Si 15 B 14 The specific preparation method of Cr2 alloy material is as follows:

[0074] Step 1: Mix raw materials Co, Fe, Ni, Si, B, and Cr with a purity greater than 99.5% according to the compositional relationship Co 64.14 Fe 3.89 Ni 0.97 Si 15 B 14 Cr2 is used for batching, and the weighing error is controlled within 0.0005g;

[0075] Step 2: Place the pre-prepared raw materials into a clean alumina crucible, put it into an induction melting furnace, and evacuate to below -0.002 Pa under an argon atmosphere. After melting, hold at the temperature for more than 10 minutes, then pour the molten alloy into a copper mold and cool in the furnace for 25 minutes to obtain a homogeneous master alloy ingot.

[0076] Step 3: After crushing the master alloy ingot obtained in Step 2, load it into a quartz tube with a nozzle of approximately 60mm. Adjust the distance between the tube opening and the roller surface to approximately 0.25mm, then evacuate to less than 0.02Pa. Adjust the pressure difference between the inside and outside of the quartz tube to 0.02MPa, and use a single-roller rapid quenching spinning process under an argon protective atmosphere, spinning the strip at a speed of 40m / s. That is, set the copper roller speed to 4000r / min and connect the heating current. When the solenoid heats and melts the master alloy ingot until it is completely melted and a white light and shaking phenomenon is observed, turn off the heating current and press the spray button simultaneously to obtain a continuous amorphous alloy strip. The strip width is 60mm and the thickness is 30μm.

[0077] Example 3

[0078] In this embodiment, the molecular formula of the cobalt-based amorphous soft magnetic alloy material is Co. 63.21 Fe 3.83 Ni 0.96 Si 15 B 14 The specific preparation method of Cr3 alloy material is as follows:

[0079] Step 1: Mix raw materials Co, Fe, Ni, Si, B, and Cr with a purity greater than 99.5% according to the compositional relationship Co 63.21 Fe 3.83 Ni 0.96 Si 15 B 14 Cr3 is used for batching, and the weighing error is controlled within 0.0005g;

[0080] Step 2: Place the pre-prepared raw materials into a clean alumina crucible, put it into an induction melting furnace, and evacuate to below -0.002 Pa under an argon atmosphere. After melting, hold at the temperature for more than 10 minutes, then pour the molten alloy into a copper mold and cool in the furnace for 25 minutes to obtain a homogeneous master alloy ingot.

[0081] Step 3: After crushing the master alloy ingot obtained in Step 2, load it into a quartz tube with a nozzle of approximately 60mm. Adjust the distance between the tube opening and the roller surface to approximately 0.25mm, then evacuate to less than 0.02Pa. Adjust the pressure difference between the inside and outside of the quartz tube to 0.02MPa, and use a single-roller rapid quenching spinning process under an argon protective atmosphere, spinning the strip at a speed of 40m / s. That is, set the copper roller speed to 4000r / min and connect the heating current. When the solenoid heats and melts the master alloy ingot until it is completely melted and a white light and shaking phenomenon is observed, turn off the heating current and press the spray button simultaneously to obtain a continuous amorphous alloy strip. The strip width is 60mm and the thickness is 30μm.

[0082] Comparative Example 1

[0083] In this embodiment, the molecular formula of the cobalt-based amorphous soft magnetic alloy material is Co. 66 Fe4NiSi 15 B 14 The specific preparation method of this alloy material is as follows:

[0084] Step 1: Combine raw materials Co, Fe, Ni, Si, and B with a purity greater than 99.5% according to the compositional relationship Co 66 Fe4NiSi 15 B 14 During ingredient preparation, the weighing error should be controlled within 0.0005g;

[0085] Step 2: Place the pre-prepared raw materials into a clean alumina crucible, put it into an induction melting furnace, and evacuate to below -0.002 Pa under an argon atmosphere. After melting, hold at the temperature for more than 10 minutes, then pour the molten alloy into a copper mold and cool in the furnace for 25 minutes to obtain a homogeneous master alloy ingot.

[0086] Step 3: After crushing the master alloy ingot obtained in Step 2, load it into a quartz tube with a nozzle of approximately 60mm. Adjust the distance between the tube opening and the roller surface to approximately 0.25mm, then evacuate to less than 0.02Pa. Adjust the pressure difference between the inside and outside of the quartz tube to 0.02MPa, and use a single-roller rapid quenching spinning process under an argon protective atmosphere, spinning the strip at a speed of 40m / s. That is, set the copper roller speed to 4000r / min and connect the heating current. When the solenoid heats and melts the master alloy ingot until it is completely melted and a white light and shaking phenomenon is observed, turn off the heating current and press the spray button simultaneously to obtain a continuous amorphous alloy strip. The strip width is 60mm and the thickness is 30μm.

[0087] Performance testing

[0088] Figure 1The XRD patterns obtained by structural characterization of the alloy strips prepared in Examples 1, 2, 3 and Comparative Example 1 using an X-ray diffractometer of model D8 ADVANCE are shown. The patterns show that all alloy materials exhibit only one broadened diffuse diffraction peak at 45 degrees, which is a typical amorphous diffuse scattering peak, indicating that the obtained alloy materials have a completely amorphous structure and possess excellent amorphous forming ability.

[0089] Figure 2 The images shown are obtained by testing the saturation magnetic induction intensity of the alloy materials prepared in Examples 1, 2, 3, and Comparative Example 1 using a vibrating sample magnetometer (VSM, LakeShore: 7410). As can be seen from the images, the saturation magnetic induction intensity of the alloy materials in the examples is significantly lower than that in the comparative example, and is below 0.55T, while maintaining a high aspect ratio. This indicates that the alloy composition in this invention can effectively improve the soft magnetic properties of the alloy materials, and the low saturation magnetic induction intensity enables the materials to possess better low-frequency magnetic properties, thereby increasing the effective absorption bandwidth of the absorbing material.

[0090] The soft magnetic properties test results of the amorphous alloy materials prepared in the examples and comparative examples are summarized in Table 1. It can be seen that by adjusting the ratio of Co, Fe, and Ni elements and adding different amounts of Cr, the magnetic properties of the alloy can be significantly affected. When the Co content decreased from 65.07% to 63.21%, the Fe content from 3.94% to 3.83%, and the Ni content from 0.99% to 0.96%, the saturation magnetization of the alloy showed a significant upward trend with the gradual increase of the Cr content, increasing from 43.37 emu / g to 54.58 emu / g. Although the saturation magnetic induction decreased slightly (from 0.52T to 0.39T), compared with the control sample without added Cr, this invention, by precisely controlling the ratio of each element, can maintain good magnetic properties while potentially achieving superior overall performance through the introduction of Cr.

[0091] Table 1: Soft magnetic properties of amorphous alloy materials prepared in the examples and comparative examples

[0092]

[0093] Figure 3The image shows the potential polarization curves obtained from corrosion resistance tests of the alloy materials prepared in Examples 1, 2, 3, and Comparative Example 1 using a Chenhua CHI660E electrochemical workstation. To better simulate actual conditions and obtain accurate test results, a three-electrode system was used in this experiment. A saturated calomel electrode served as the reference electrode, a platinum electrode as the auxiliary electrode, and a 3.5 wt.% NaCl solution (pH = 7) was selected as the electrolyte solution. The experimental design specifically considered similarity to practical applications, with the alloy strip directly immersed in the electrolyte solution as the working electrode. Before the formal testing began, the surface of the alloy samples needed to be polished to remove the surface oxide film. Furthermore, to ensure the smooth progress of the experiment, additional precautions were taken, namely, wrapping the sharp corners of the samples with paraffin wax to prevent unnecessary discharge phenomena in these areas. These detailed considerations contribute to improving the reliability and practical value of the experimental data.

[0094] Figure 3 The polarization curve test results show that, compared with the comparative example, the corrosion potential (Ecorr) of the embodiment shifts positively, the corrosion current density decreases, and a clear passivation region appears. This indicates that the addition of Cr improves the corrosion resistance of the alloy, and the formed passivation film further inhibits corrosion. This improvement not only enhances the stability of the alloy during preparation and use but also reduces the requirements for a vacuum environment, thereby helping to reduce production costs.

[0095] Using the cobalt-based amorphous soft magnetic alloy material prepared in Example 1 as the frequency selective surface, a composite absorbing structure was fabricated using CST STUDIOSUITE 2019 simulation to obtain the performance of the composite absorbing structure.

[0096] Example 4

[0097] Step 1: Launch CST STUDIO SUITE 2019 software; select the "Microwave & RF" module on the main interface to enter the electromagnetic simulation settings interface;

[0098] Step 2:

[0099] 2-1. Modeling the upper dielectric substrate: In the modeling window, select "Create" - "Brick" to create a rectangle; set the size parameters of the rectangle: length = 90mm, width = 90mm, height = 2mm; define the material properties, select "New Material" in the "Material" menu, enter the electromagnetic parameters of the material, and name it "Absorber1"; apply the material properties to the created rectangle;

[0100] 2-2. Modeling the lower dielectric substrate: In the modeling window, repeat the steps to create the rectangle, setting its dimensions: length = 90mm, width = 90mm, height = 1.5mm; set its position parameters to maintain a certain distance from the upper dielectric substrate; define the material properties, select "New Material" in the "Material" menu, enter the electromagnetic parameters of the material, and name it "Absorber2"; apply the material properties to the created rectangle.

[0101] 2-3. Frequency Selective Surface (FSS) Modeling: In the modeling window, select "Create"—"Polygon"—"Cross" to draw a cross-shaped pattern; set the pattern's dimensions (arm length = 35mm, arm width = 25mm, thickness = 0.03mm), defining it in the center of the dielectric substrate; define the material properties by selecting "New Material" from the "Material" menu, entering the material's electromagnetic parameters (S = 7.14E7, M = 1.5), and naming it "FSS Material"; apply the material properties to the created cross-shaped pattern, arranging them as follows... Figure 4 As shown, the rows and columns are arranged in a periodic extension pattern, and the spacing between the cross patterns is 55mm; the position parameters of the patterns relative to the upper and lower dielectric substrates are set so that they are located in the middle.

[0102] Step 3:

[0103] 3-1. Boundary Conditions: In the "Boundary Conditions" menu, Z... min Select "electric (Et=0)" to simulate a perfect conductor; Z max Select "Open (add space)" to simulate an open space; set the min and max boundaries of X and Y to "unit cell";

[0104] 3-2. Excitation Source: In the "Simulation" menu, select "Waveguide Port" to define the excitation source; set the frequency range of the excitation source (1GHz to 18GHz); locate the position of the excitation port so that it coincides with the incident surface of the model;

[0105] 3-3. Mesh Generation: The mesh generation is set to automatically generate tetrahedral meshes.

[0106] Step 4: In the "Solver" menu, select "Transient Solver" or "Frequency DomainSolver"; set the simulation frequency step size to 0.017GHz; click the "Start" button to start the simulation calculation;

[0107] Step 5: Select “S-Parameters” to view the curve of scattering parameter S11 as a function of frequency; export the simulation results and organize and analyze them.

[0108] Comparative Example 2

[0109] Step 1: Launch CST STUDIO SUITE 2019 software; select the "Microwave & RF" module on the main interface to enter the electromagnetic simulation settings interface;

[0110] Step 2:

[0111] 1. Modeling the upper dielectric substrate: In the modeling window, select "Create" - "Brick" to create a rectangle; set the size parameters of the rectangle: length = 90mm, width = 90mm, height = 2mm; define the material properties, select "New Material" in the "Material" menu, enter the electromagnetic parameters of the material, and name it "Absorber2"; apply the material properties to the created rectangle;

[0112] 2. Modeling the lower dielectric substrate: In the modeling window, repeat the steps to create the rectangle, setting its dimensions: length = 90mm, width = 90mm, height = 1.5mm; set its position parameters to maintain a certain distance (0.03mm) from the upper dielectric substrate; define the material properties, select "New Material" in the "Material" menu, enter the electromagnetic parameters of the material, and name it "Absorber1"; apply the material properties to the created rectangle.

[0113] Step 3:

[0114] 1. Boundary conditions: In the “Boundary Conditions” menu, select “electric (Et=0)” for Zmin to simulate a perfect conductor; select “Open (add space)” for Zmax to simulate an open space; set the min and max boundaries of X and Y to “unit cell”.

[0115] 2. Excitation Source: In the "Simulation" menu, select "Waveguide Port" to define the excitation source; set the frequency range of the excitation source (1GHz to 18GHz); locate the position of the excitation port so that it coincides with the incident surface of the model;

[0116] 3. Mesh Generation: The mesh generation is set to automatically generate tetrahedral meshes;

[0117] Step 4: In the "Solver" menu, select "Transient Solver" or "Frequency DomainSolver"; set the simulation frequency step size to 0.017GHz; click the "Start" button to start the simulation calculation;

[0118] Step 5: Select “S-Parameters” to view the curve of scattering parameter S11 as a function of frequency; export the simulation results and organize and analyze them.

[0119] Examples 5-13 and Comparative Example 3

[0120] Following the steps of Example 4, the material parameters used in modeling the upper and lower dielectric plates were adjusted, as well as the arm length and arm width of the cross-shaped pattern in the frequency selection surface. The specific parameters changed and the absorption performance of the composite absorbing structure obtained from the simulation are shown in Table 2. The electromagnetic parameters corresponding to the dielectric plate materials in the example and comparative simulation are shown in Table 3.

[0121] Table 2 shows the absorption performance of the composite absorbing structure obtained from simulations of the embodiments and comparative examples.

[0122]

[0123] Table 3 shows the electromagnetic parameters of the dielectric substrate materials in the embodiments and comparative simulations.

[0124]

[0125] Table 2 shows the data that investigates the influence of different structural parameters on the absorption effect. Through a systematic study of parameters such as material, thickness, arm length, arm width, and spacing, it was found that using Absorber1 material in the upper layer results in a wider effective absorption bandwidth, increasing from 4.0 GHz to 14.7 GHz compared to Absorber4 material. This is because Absorber1 has a lower dielectric constant and moderate permeability. In contrast, although Absorber4 has a similar dielectric constant, its loss factor is significantly higher. This combination of material characteristics allows Absorber1 to achieve better impedance matching, thus obtaining a wider effective absorption bandwidth.

[0126] In terms of structural dimensions, the combination of an upper layer thickness of 2mm and a lower layer thickness of 1.5-2mm exhibits excellent wave absorption performance. When the lower layer thickness is increased from 1.5mm to 2mm, the maximum absorption can be increased from -22.6dB to -26.7dB. This is because when the lower layer thickness is increased, Absorber2's high dielectric properties provide stronger electromagnetic wave attenuation capabilities.

[0127] Regarding geometric parameters, research has found that a smaller arm width (5mm) can significantly improve the maximum absorption to -41.4dB. This is because a narrower arm width facilitates better impedance matching at specific frequencies, but it also limits the realization of wideband characteristics. Therefore, in practical applications, it is necessary to select an appropriate arm width parameter between bandwidth and absorption intensity based on specific requirements. An arm length of around 35mm is most suitable; excessive length can lead to a decrease in absorption performance. For example, when the arm length is increased to 65mm, the maximum absorption drops to -16.3dB because an excessively long arm length leads to impedance mismatch and reduces the absorption effect. At the same time, the spacing parameter also has an important impact on absorption performance. A larger spacing has a better absorption effect than a smaller spacing because a suitable spacing is conducive to the formation of effective electromagnetic coupling between adjacent elements.

[0128] By optimizing the combination of the above parameters, wide-bandwidth, strong absorption characteristics can be achieved, providing a reliable design basis for practical applications.

[0129] The reflection loss of Examples 4-13 and Comparative Examples 2-3 varies with frequency as follows: Figure 5 As shown, in improving the absorption performance of amorphous soft magnetic frequency-selective surface composite absorbing materials, we optimize the propagation path of electromagnetic waves in the material by adjusting the thickness of the upper and lower dielectric plates, thereby enhancing the absorption effect. In addition, by precisely controlling the dielectric constant and permeability of the upper and lower dielectric plates, we can change the propagation speed and attenuation characteristics of electromagnetic waves, effectively improving the absorption performance within a specific frequency range. Adjusting the arm length and arm width of the cross-shaped frequency-selective surface can respectively achieve selective absorption of specific frequencies and expand the absorption bandwidth, thereby significantly improving the overall absorption performance in multiple frequency bands.

[0130] Application examples

[0131] The cobalt-based amorphous soft magnetic alloy of this invention can be used to manufacture high-performance radar absorbing materials, and is particularly suitable for military equipment such as stealth fighters. The specific application process is as follows:

[0132] The amorphous soft magnetic material strip of Example 1 was cut into a cross pattern, and the geometric parameters are shown in Table 4. The cut alloy strips were arranged in a cross pattern on a dielectric plate. The first dielectric plate was carbonyl iron + silicone with a thickness of 2 mm, and the second dielectric plate was carbonyl iron + silicone with a thickness of 1.5 mm. The measured results of the dielectric plates represent the measured results of the first dielectric plate + the second dielectric plate without frequency selection. Figure 6 The diagram below shows the pattern arrangement in this application example. A multi-layered frequency-selective surface composite absorbing device was constructed, and the reflectivity of the resulting composite absorbing device was tested using a VNA and an Agilent N5234A vector network analyzer.

[0133] Figure 7The results show that, according to tests, the composite material using the material of this invention increases the effective absorption (RL≤-10dB) bandwidth of the original dielectric substrate from 2.6GHz to 9.4GHz in the 1-18GHz range.

[0134] Table 4 shows the parameters and performance data for each aspect in the application examples.

[0135]

[0136] The embodiments described above provide a detailed explanation of the technical solution of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A cobalt-based amorphous soft magnetic alloy material, characterized in that, The composition of the cobalt-based amorphous soft magnetic alloy material has the following expression: Co a Fe b Ni c Si d B e Cr f In the formula, a, b, c, d, e, and f represent the atomic percentages of the corresponding components, where 60≤a≤70, 2≤b≤6, 0.5≤c≤5, 10≤d≤20, 10≤e≤20, 0.5≤f≤5, and a+b+c+d+e+f=100.

2. The cobalt-based amorphous soft magnetic alloy material according to claim 1, characterized in that, The atomic percentage of Co in the cobalt-based amorphous soft magnetic alloy material is 65 ≤ a ≤ 70. The atomic percentage of Fe in the cobalt-based amorphous soft magnetic alloy material is 3 ≤ b ≤ 5; The atomic percentage of Ni in the cobalt-based amorphous soft magnetic alloy material is 0.5 ≤ c ≤ 2; The atomic percentage of Si in the cobalt-based amorphous soft magnetic alloy material is 14 ≤ d ≤ 17. The atomic percentage of B in the cobalt-based amorphous soft magnetic alloy material is 10 ≤ e ≤ 15. The atomic percentage of Cr in the cobalt-based amorphous soft magnetic alloy material is 0.5 ≤ f ≤ 3.

5.

3. The cobalt-based amorphous soft magnetic alloy material according to claim 1, characterized in that, The atomic percentage of Cr in the cobalt-based amorphous soft magnetic alloy material is 0.5 ≤ f ≤ 3.

4. The method for preparing cobalt-based amorphous soft magnetic alloy material according to any one of claims 1-3, characterized in that, The process includes the following steps: Step 1, weighing and melting the raw materials according to the alloy composition to form a master alloy ingot; Step 2, making the master alloy ingot into an amorphous soft magnetic alloy strip.

5. The method for preparing cobalt-based amorphous soft magnetic alloy material according to claim 4, characterized in that, Step 2 involves preparing amorphous soft magnetic alloy strips using at least one of the following methods: single-roll rapid quenching, vacuum spray casting, and medium-frequency induction melting.

6. The method for preparing cobalt-based amorphous soft magnetic alloy material according to claim 4, characterized in that, When the method for preparing amorphous soft magnetic alloy strip in step 2 is single-roll rapid quenching, the process parameters of single-roll rapid quenching are: spray pressure of 0.01-0.03MPa and copper roller rotation speed of 3000-5000r / min.

7. The application of the cobalt-based amorphous soft magnetic alloy material according to any one of claims 1-3 as a material for the frequency selective surface layer in a composite absorbing device.

8. A composite absorbing structure based on a frequency-selective surface of an amorphous soft magnetic alloy, characterized in that, The composite absorbing structure comprises, from top to bottom, a first dielectric substrate layer, a frequency selective surface layer, and a second dielectric substrate layer; the frequency selective surface layer is made of the cobalt-based amorphous soft magnetic alloy material as described in any one of claims 1-3.

9. The composite absorbing structure based on a frequency-selective surface of an amorphous soft magnetic alloy according to claim 8, characterized in that, The frequency selection surface layer has a thickness of 0.02-0.05 mm and includes multiple FSS units arranged in a row and column period of 10-90 mm. The FSS units are equal-length cross patterns with a spacing of 5-60 mm.

10. The composite absorbing structure based on an amorphous soft magnetic alloy frequency-selective surface according to claim 9, characterized in that, The cross pattern has an arm length of 30-85mm and an arm width of 15-25mm.

11. The composite absorbing structure based on a frequency-selective surface of an amorphous soft magnetic alloy according to claim 8, characterized in that, The thickness of the first dielectric substrate layer is 1-2 mm, the real part of the complex dielectric constant ε' is 5.5-7.5, the imaginary part of the complex dielectric constant ε” is 0.1-1, the real part of the complex permeability μ' is 2.3-3.1, the imaginary part of the complex permeability μ” is 0.4-0.7, and the loss factor is 0.03-0.

13.

12. The composite absorbing structure based on an amorphous soft magnetic alloy frequency-selective surface according to claim 8, characterized in that, The thickness of the second dielectric substrate layer is 1-2 mm, the real part of the complex dielectric constant ε' is 15.5-17, the imaginary part of the complex dielectric constant ε” is 0.2-0.4, the real part of the complex permeability μ' is 3.1-4.3, the imaginary part of the complex permeability μ” is 0.6-1.9, and the loss factor is 0.02-0.

03.

13. The composite absorbing structure based on an amorphous soft magnetic alloy frequency-selective surface according to claim 8, characterized in that, The first dielectric substrate layer is made of one or more of nickel-zinc ferrite, carbon fiber, and carbonyl iron, mixed with one or more of silicone, epoxy resin, and polyurethane. The material of the second dielectric substrate layer includes one or more of nickel-zinc ferrite, carbon fiber, and carbonyl iron, which are mixed with one or more of silicone, epoxy resin, and polyurethane.

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