A composite soft magnetic material, its preparation method, and its applications

Abstract

This application discloses a composite soft magnetic material, comprising a soft magnetic material and a metal, wherein the metal includes copper and silver, and the metal is coated on the surface of the soft magnetic material; the soft magnetic material includes soft magnetic metals and soft magnetic alloys. This application further discloses a method for preparing the above-mentioned composite soft magnetic magnetic or filamentous material. Furthermore, an inductor coil is prepared using the above-mentioned composite soft magnetic magnetic or filamentous material. The inductor coil exhibits a very excellent quality factor under high-frequency operating conditions and a very low inductance under low-frequency operating conditions. Therefore, the inductor coil prepared using the composite soft magnetic magnetic or filamentous material described in this application has very low energy loss, making it particularly suitable for large-scale applications.

Description

Technical Field

[0001] This application relates to a method for preparing a composite soft magnetic material, belonging to the field of induction coils. Background Technology

[0002] Modern electronic devices extensively utilize System-on-Chip (SoC) technology to achieve high-frequency operation, miniaturization, lightweight design, high reliability, and multifunctionality. The normal operation of SoCs relies heavily on high-performance surface-mount inductors. Inductors are widely used in AC electronic equipment, especially in wireless devices, where, along with capacitors and resistors, they constitute the three major passive linear components of electronic circuits. The main applications of inductors include oscillators, chokes, filters, and, in combination with capacitors, tuning circuits and impedance matching. With the further development of electronic information technology, inductors, as key components, play a crucial role in the electronic information industry, especially in core power modules, sensors, and radio frequency circuits, where they are essential for system stability and reliability.

[0003] Amorphous (including nanocrystalline structures) soft magnetic materials are a new type of material that emerged in the 1970s. Due to their advantages such as low core loss, high resistivity, good frequency characteristics, high magnetic induction intensity, and strong corrosion resistance, they have attracted great attention and are hailed as a new type of green and energy-saving material for the 21st century. The excellent soft magnetic properties of amorphous and nanocrystalline alloys stem from their unique microstructure. Amorphous structures lack grains and grain boundaries, making them easy to magnetize; the grain size in nanocrystalline structures is smaller than the magnetic exchange interaction length, resulting in very small average magnetocrystalline anisotropy, and by adjusting the composition, their magnetostriction can be made close to zero.

[0004] Directly fabricating inductors using amorphous soft magnetic materials can significantly reduce the inductor area while effectively improving performance, which will further enhance the integration of electronic circuits. However, compared to ordinary metals or alloys, amorphous materials have a very high resistivity, resulting in significant ohmic losses when used directly as inductor coils, negatively impacting the inductor's quality factor (Q). For inductors, the quality factor (Q) is a crucial parameter. The Q is the ratio of stored energy to lost energy; a higher Q indicates lower power consumption and higher efficiency. However, using amorphous soft magnetic materials directly as the inductor coil conductors presents a significant challenge because the resistivity of amorphous materials is much higher than that of copper (approximately 1.75 × 10⁻⁶). -2 According to Ohm's law, when current flows, the ohmic losses generated by a high-resistivity metal coil are much greater than those of a low-resistivity metal coil, resulting in a very low Q value for the inductor.

[0005] The main measures reported so far to improve the Q value of inductor coils include using low resistivity metals to make thick metal coils to reduce ohmic losses. Thick metal coils do not affect the mechanical stability of the inductor, but they require thick photoresist lithography and thick metal electroplating processes, which are difficult to manufacture. At the same time, the increase in metal thickness will also lead to a more significant proximity effect and parasitic capacitance effect between coils, affecting the Q value of the inductor.

[0006] In addition, the quality factor Q of thin-film inductors can be improved by reducing substrate losses. High resistivity silicon can be used to suppress substrate-induced losses such as eddy currents. However, the charge accumulated at the interface between the silicon substrate and the dielectric (SiO2) layer makes the Q factor unsuitable for many high-frequency applications. Summary of the Invention

[0007] This application prepares an inductor coil by coating a soft magnetic surface with a layer of low resistivity metal, thereby reducing ohmic losses and improving the quality factor of the inductor.

[0008] According to the first aspect of this application, a composite soft magnetic material is provided.

[0009] A composite soft magnetic material, the composite soft magnetic material comprising a soft magnetic material and a low resistivity metal;

[0010] The composite soft magnetic material is in the shape of a strip or a filament;

[0011] The low resistivity metal is selected from at least one of copper and silver;

[0012] The low resistivity metal is coated on the surface of the soft magnetic material.

[0013] Optionally, the ratio of the low resistivity metal to the soft magnetic material, by weight, is 1:10–1:300.

[0014] Optionally, the saturation magnetic induction of the composite soft magnetic material is 0.5–2.2T; the coercivity of the composite soft magnetic material is 0.01–100A / m.

[0015] Optionally, in the composite soft magnetic material, the soft magnetic material has the following chemical formula:

[0016] Fe a Co b Ni c M 100-a-b-c ; at.%; 60≦a+b+c≦100; M is selected from at least one of Si, B, P, C, Cu, Zr, Nb, Mo, Hf, Ag, Au, Cu, Ti, V, Zn, Ga, Sn, Pd, Y, W, Pt, and Al.

[0017] Optionally, when any one of a, b, and c is 100, the soft magnetic material does not contain the M element.

[0018] According to a second aspect of this application, a method for preparing the aforementioned composite soft magnetic material is provided.

[0019] A first method for preparing composite soft magnetic materials includes the following steps:

[0020] The soft magnetic material is immersed in a solution containing a copper source and reacted to obtain the composite soft magnetic material.

[0021] Optionally, the copper source is selected from at least one of copper sulfate, copper nitrate, and copper chloride.

[0022] Optionally, the copper ion concentration in the copper-containing solution is 0.05–0.5 mol / L.

[0023] Optionally, the reaction time is 15–120 s.

[0024] Alternatively, a voltage can be applied to the soft magnetic material before the reaction proceeds.

[0025] Optionally, the voltage is 1–2V.

[0026] According to a third aspect of this application, a second method for preparing the aforementioned composite soft magnetic material is provided.

[0027] A second method for preparing composite soft magnetic materials includes the following steps:

[0028] The composite soft magnetic material is obtained by coating the surface of a soft magnetic material with metallic copper.

[0029] Optionally, the coating is selected from one of thermal spraying, supersonic cold spraying, magnetron sputtering, and ion beam assisted deposition.

[0030] Based on the two methods described above, a low-resistivity metal layer can be coated onto the surface of the soft magnetic material. This coating metal layer can effectively reduce the resistivity of the soft magnetic material, thereby reducing the ohmic loss of the inductor coil and further obtaining an inductor coil with high inductance and high quality factor.

[0031] The composite soft magnetic material obtained by the above method has a high saturation magnetic induction intensity. The inductor coil made from this material has high power density output characteristics, which is beneficial to realizing high integration and miniaturization of devices in large-scale integrated circuits.

[0032] The composite soft magnetic material obtained by the above method has good flexibility and plasticity, can be prepared into various forms, the preparation process is simple, the obtained composite soft magnetic material has high uniformity and the electromagnetic performance of the inductor coil is stable.

[0033] According to the fourth aspect of this application, the above-mentioned composite soft magnetic material and the composite soft magnetic material obtained by the above two preparation methods are provided for use in inductor coils.

[0034] The quality factor of the inductor coil is 2–20 when the number of turns is 10.

[0035] The inductor coil has an inductance of 0.5–10 μH when the number of turns is 10.

[0036] The beneficial effects that this application can produce include:

[0037] 1) The method for preparing composite soft magnetic materials provided in this application is simple and efficient;

[0038] 2) The method for preparing composite soft magnetic materials provided in this application can reduce the resistivity of soft magnetic materials, thereby enabling inductors to simultaneously possess high power density output characteristics and high quality factor when using the composite soft magnetic materials to prepare inductors. This provides a solution to the bottleneck problem of the industry's inductors having difficulty achieving both excellent performance.

[0039] 3) The method for fabricating a high-quality factor inductor coil provided in this application allows for control of the coating thickness and uniformity by adjusting the solution concentration and reaction time. This method forms a low-resistivity copper or silver coating on the surface of soft magnetic materials, significantly reducing the ohmic loss of the inductor coil and ultimately improving its quality factor. This method is simple, the metal (copper / silver) coating is controllable and can be maintained at the micro-nano scale, avoiding the degradation of overall inductor performance due to coil proximity effects and parasitic capacitance effects. Attached Figure Description

[0040] Figure 1 For Examples 1–4 of this application, (Fe6Co) 94 ) 0.725 Si 12.5 B 15 The X-ray diffraction (XRD) images of the bands of the soft magnetic material after reacting with 0.2 mol / L CuSO4 solution for 15 s, 30 s, 45 s and 60 s are shown in the figure. To show the difference between the treated sample and the untreated sample, the sample of the soft magnetic material reacting with CuSO4 for 0 s is shown as Comparative Example 1 in this figure.

[0041] Figure 2 For Examples 1–4 of this application, (Fe6Co) 94 ) 0.725 Si 12.5 B 15Resistivity plots of the soft magnetic material after reacting with CuSO4 solution for 15 s, 30 s, 45 s, and 60 s. To show the difference between the treated and untreated samples, the sample of soft magnetic material reacting with CuSO4 for 0 s (as-spun) is shown as Comparative Example 1 in this figure.

[0042] Figure 3 For Examples 1–4 of this application, (Fe6Co) 94 ) 0.725 Si 12.5 B 15 The graph shows the inductance of the composite soft magnetic material wound into an inductor coil after reacting with 0.2 mol / L CuSO4 solution for 15 s, 30 s, 45 s, and 60 s, as a function of frequency. To illustrate the difference between the treated and untreated samples, a sample with the soft magnetic material reacting with CuSO4 for 0 s and a sample prepared from pure Cu material are presented as Comparative Example 1 in this graph.

[0043] Figure 4 For Examples 1–4 of this application, (Fe6Co) 94 ) 0.725 Si 12.5 B 15 The quality factor Q of the composite soft magnetic material after reacting with 0.2 mol / L CuSO4 solution for 15 s, 30 s, 45 s, and 60 s is shown in the figure when wound into inductor coils. To illustrate the difference between the treated and untreated samples, a sample with the soft magnetic material reacting with CuSO4 for 0 s and a sample prepared from pure Cu material are presented as Comparative Example 1.

[0044] Figure 5 Fe for Examples 5–8 of this application 73.5 Si 13.5 XRD patterns of the composite soft magnetic material after reacting B9Cu1Nb3 soft magnetic material with 0.2 mol / L CuSO4 solution for 15 s, 30 s, 45 s, and 60 s. To show the difference between the treated and untreated samples, the sample in which the soft magnetic material reacted with CuSO4 for 0 s is shown as Comparative Example 2 in this figure.

[0045] Figure 6 Fe for Examples 5–8 of this application 73.5 Si 13.5 The graph shows the inductance of the composite soft magnetic material (B9Cu1Nb3) wound into an inductor coil after reacting with 0.2 mol / L CuSO4 solution for 15 s, 30 s, 45 s, and 60 s, as a function of frequency. To illustrate the difference between the treated and untreated samples, a sample with the soft magnetic material reacting with CuSO4 for 0 s and a sample prepared from pure Cu material are presented as Comparative Example 2 in this graph.

[0046] Figure 7 Fe for Examples 5–8 of this application 73.5 Si 13.5 The quality factor Q of the composite soft magnetic material B9Cu1Nb3 reacted with 0.2 mol / L CuSO4 solution for 15 s, 30 s, 45 s, and 60 s, and then wound into inductor coils. To show the difference between the treated and untreated samples, the sample in which the soft magnetic material reacted with CuSO4 for 0 s is shown as Comparative Example 2 in this figure.

[0047] Figure 8 Fe for Examples 9–12 of this application 73.5 Si 13.5 The graph shows the inductance of the composite soft magnetic material (B9Cu1Nb3) wound into an inductor coil after reacting with AgNO3 in a 1.5V, 0.4mol / L solution for 15s, 30s, 45s, and 60s, as a function of frequency. To illustrate the difference between the treated and untreated samples, a sample with the soft magnetic material reacting with AgNO3 for 0s and a sample prepared from pure Cu material are presented as Comparative Example 3 in this graph.

[0048] Figure 9 Fe for Examples 9–12 of this application 73.5 Si 13.5 The quality factor Q of the composite soft magnetic material B9Cu1Nb3 after reacting in a 0.4 mol / L AgNO3 plating bath at 1.5 V for 15 s, 30 s, 45 s, and 60 s, when wound into inductor coils, is shown in the figure. To illustrate the difference between the treated and untreated samples, a sample with the soft magnetic material reacting with AgNO3 for 0 s and a sample prepared from pure Cu material are presented as Comparative Example 3. Detailed Implementation

[0049] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0050] Unless otherwise specified, the raw materials used in the embodiments of this application were purchased commercially, and copper sulfate pentahydrate was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with a purity of 99%.

[0051] Among them, the amorphous alloy soft magnetic material is prepared in the laboratory. The specific preparation process is as follows: the raw materials are prepared according to the atomic fraction of each element in the required composition and then prepared into a master alloy ingot by induction melting. The desired amorphous soft magnetic tape alloy is then obtained by single-roller spinning.

[0052] Metals and other alloy-type strip and wire soft magnetic materials (iron, cobalt, nickel metals) were purchased from the market. Iron metals, cobalt metals, nickel metals, etc. were all purchased from Zhongnuo New Materials (Beijing) Technology Co., Ltd.

[0053] The analysis method in the embodiments of this application is as follows:

[0054] XRD analysis was performed using a Bruker D8 DISCOVER X-ray diffractometer.

[0055] Resistivity was measured using the RTS-9 dual-electric four-probe tester with a four-probe method.

[0056] Inductance values ​​were measured using an Agilent 4294A precision impedance analyzer.

[0057] The quality factor (Q value) was tested using an Agilent 4294A precision impedance analyzer.

[0058] Examples 1–4

[0059] (Fe6Co 94 ) 0.725 Si 12.5 B 15 Preparation of composite soft magnetic materials.

[0060] (Fe6Co) 94 ) 0.725 Si 12.5 B 15 The soft magnets were placed in a 0.2 mol / L CuSO4 solution and reacted for 15 s, 30 s, 45 s, and 60 s, respectively, and labeled as Examples 1–4; the resulting strip-shaped materials (strips) were subjected to XRD, as shown in the figure. Figure 1 As shown, characteristic peaks of Cu appeared after calibration.

[0061] The resistivity of the composite soft magnetic materials described in Examples 1–4 was tested using the four-probe method. Figure 2 As shown, the resistivity of the composite soft magnetic material decreases with increasing reaction time.

[0062] The (Fe6Co) reacted with CuSO4 solution 94 ) 0.725 Si 12.5 B 15 A 10-turn air-core inductor coil was wound using composite soft magnetic material. The inductance of the amorphous soft magnetic inductor coil in this embodiment was measured using an Agilent 4294A precision impedance analyzer. The results are as follows: Figure 3 As shown, the inductance of the inductor coil wound from the Cu-plated strip is lower than that of the inductor coil wound from the original strip. The Q value of the amorphous soft magnetic inductor coil in this embodiment was measured using an Agilent 4294A precision impedance analyzer, and the results are as follows. Figure 4 The Q value of the inductor coil wound from the Cu-plated strip is significantly higher than that of the original strip-wound inductor coil.

[0063] Examples 5–8

[0064] Fe 73.5 Si 13.5 Preparation of B9Cu1Nb3 composite soft magnetic materials.

[0065] Fe 73.5 Si 13.5 B9Cu1Nb3 soft magnetic material was placed in a 0.2 mol / L CuSO4 solution and reacted for 15 s, 30 s, 45 s, and 60 s, respectively, corresponding to Examples 5–8; the resulting composite soft magnetic material was subjected to XRD, as shown below. Figure 5 As shown, characteristic peaks of Cu appeared after calibration.

[0066] Fe after reacting with CuSO4 solution 73.5 Si 13.5 A 10-turn air-core inductor coil was wound using B9Cu1Nb3 composite soft magnetic material. The inductance of the amorphous soft magnetic inductor coil in this embodiment was measured using an Agilent 4294A precision impedance analyzer. The results are as follows: Figure 6 As shown, the inductance of the inductor coil wound from the Cu-plated strip is lower than that of the original strip-wound inductor coil, but the effect of different response times on the inductance is not significant. The Q value of the amorphous soft magnetic inductor coil in this embodiment was measured using an Agilent 4294A precision impedance analyzer, and the results are as follows. Figure 7 As shown, the Q value of the inductor coil wound from the Cu-plated strip is significantly higher than that of the original strip-wound inductor coil.

[0067] Examples 9–12

[0068] Fe 73.5 Si 13.5 Preparation of B9Cu1Nb3 composite soft magnetic materials.

[0069] Fe 73.5 Si 13.5 The B9Cu1Nb3 composite soft magnetic material was reacted in a 0.4 mol / L AgNO3 plating solution at a voltage of 1.5 V for 15 s, 30 s, 45 s and 60 s, respectively, corresponding to Examples 9–12.

[0070] Electroplated Fe 73.5 Si 13.5 A 10-turn air-core inductor coil was wound using B9Cu1Nb3 composite soft magnetic material. The inductance of the amorphous soft magnetic inductor coil in this embodiment was measured using an Agilent 4294A precision impedance analyzer. The results are as follows: Figure 8 As shown, the inductance of the inductor coil wound from the Ag-plated strip is lower than that of the inductor coil wound from the original strip, but the effect of different response times on the inductance is not significant. The Q value of the amorphous soft magnetic inductor coil in this embodiment was measured using an Agilent 4294A precision impedance analyzer, and the results are as follows. Figure 9 As shown, the Q value of the inductor coil wound from the Ag-plated strip is significantly improved compared to the inductor coil wound from the original strip.

[0071] Comparative Examples 1-3

[0072] (Fe6Co) 94 ) 0.725 Si 12.5 B 15 Soft magnetic materials and Fe 73.5 Si 13.5 The B9Cu1Nb3 soft magnetic material was directly subjected to XRD and resistivity tests. Furthermore, the material was wound into 10-turn coils for Q-value and inductance testing. The test results are presented below. Figure 1 –9. See the attached diagram for details.

[0073] This application provides a method for preparing a high-inductance, high-Q inductor coil based on soft magnetic materials, which significantly improves the quality factor Q of the inductor coil. The raw materials used in this application are of moderate cost, the experimental method is simple and feasible, the process is easy to control, and it is easy to obtain an inductor coil with both high inductance and high Q value, which is conducive to its widespread application and large-scale mass production.

[0074] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing a composite soft magnetic material, characterized in that, The preparation method is as follows: The soft magnetic material is immersed in a copper source solution and reacted to obtain the composite soft magnetic material; The copper source is selected from at least one of copper sulfate, copper nitrate, and copper chloride. The copper source solution has a copper ion concentration of 0.05 – 0.5 mol / L; The reaction time is 15–120 s; The composite soft magnetic material includes soft magnetic materials and low resistivity metals; The composite soft magnetic material is in the shape of a strip or a filament; The low resistivity metal is selected from copper; The low resistivity metal is coated on the surface of the soft magnetic material; The ratio of the low resistivity metal to the soft magnetic material, by weight, is 1:10 – 1:

300.

2. The preparation method according to claim 1, characterized in that, The saturation magnetic induction of the composite soft magnetic material is 0.5 – 2.2 T; the coercivity of the composite soft magnetic material is 0.01 – 100 A / m.

3. The preparation method according to claim 1, characterized in that, The composite soft magnetic material has the following chemical formula: Feb a Co b Ni c M 100-a-b-c ; at.%; 60≦a+b+c<100; M is selected from at least one of Si, B, P, C, Cu, Zr, Nb, Mo, Hf, Ag, Au, Cu, Ti, V, Zn, Ga, Sn, Pd, Y, W, Pt, and Al.

4. The composite soft magnetic material obtained by the preparation method according to any one of claims 1–3, in the application of inductor coils; The inductor coil has a quality factor of 2-20 when the number of turns is 10. The inductor coil has an inductance of 0.5 – 10 μH when the number of turns is 10.

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