Preparation method of high-thermal-conductivity flaky metal soft magnetic composite material with sandwich structure

Abstract

The invention discloses a preparation method of a high-thermal-conductivity flaky metal soft magnetic composite material with a sandwich structure, which belongs to the technical field of high-frequency integrated inductors, and particularly comprises the following steps: mixing phosphatized flaky FeSiAl powder, nano MnZn ferrite powder, flaky GO dispersion liquid, nano AlN and PVB powder in absolute ethyl alcohol, and carrying out vacuum defoaming, film casting, heating curing and laminated pressing on the obtained slurry to obtain the high-thermal-conductivity flaky metal soft magnetic composite material with the sandwich structure. The high-thermal-conductivity sheet-shaped metal soft magnetic composite material of the sandwich structure is obtained. The sheet GO-nano AlN mixed heat conduction system is utilized to construct a heat conduction path, rapid conduction of heat is achieved, and the heat dissipation capacity of the high-frequency integrated inductor is improved.

Description

Technical Field

[0001] This invention belongs to the field of high-frequency integrated inductor technology, specifically relating to a method for preparing a sandwich-structured, high thermal conductivity sheet-like soft magnetic metal composite material. Background Technology

[0002] With the rapid rise of fields such as artificial intelligence (AI), new energy, mobile communications, and consumer electronics, the high-frequency, integrated, and miniaturized nature of electronic systems has become a core direction for performance breakthroughs. Currently, the rapid development of microelectronics technology is driving a continuous improvement in integration levels. In addition to the large-scale integration of basic components such as resistors, capacitors, and transistors, high-power inductors are also gradually moving towards silicon-based or printed circuit board (PCB) integration. This trend is not only crucial for meeting system miniaturization requirements but also a core need for adapting to high-frequency operating conditions. However, the integration process significantly increases the component density per unit area of ​​integrated circuits, leading to a sharp increase in heat flux density. Increased device temperature severely affects system performance and energy efficiency, creating a vicious cycle: on the one hand, high temperatures deteriorate the performance and stability of device materials, further increasing power consumption and exacerbating heat generation, even leading to device failure; on the other hand, the high temperature of a single device spreads to its surroundings, disrupting the normal operating environment of neighboring devices. It is particularly noteworthy that magnetic devices such as inductors and transformers are among the main heat sources in electronic systems and often occupy a large area. Their integrated nature further exacerbates heat generation, becoming a bottleneck restricting the overall performance improvement of electronic systems. Therefore, in response to the core heat dissipation challenge faced by electronic systems under the trend of integration, developing integrated inductors with both high thermal conductivity and high frequency adaptability has become a key requirement for ensuring system reliability and performance breakthroughs.

[0003] High-frequency integrated inductors are mainly composed of a soft magnetic composite material, a binder, and an external coil. On one hand, under high-frequency operating conditions, the inductor core generates magnetic losses, and the coil windings experience copper losses due to current flow; these two factors together constitute the main sources of heat generation in integrated inductors. On the other hand, the addition of a large amount of low thermal conductivity organic binder increases the thermal resistance of the soft magnetic composite material, making it difficult for the heat generated by the losses to be quickly conducted outwards. The combined effect of increased heat generation and impaired heat dissipation causes a large amount of heat to accumulate inside the inductor, leading to a sharp rise in device temperature. Simultaneously, the increased temperature deteriorates the inductor's performance, causing a further rise in temperature, which in turn affects the performance and stability of the inductor itself and surrounding components.

[0004] Currently, the heat dissipation methods used in the field of high-frequency integrated inductor devices are still mainly external auxiliary heat dissipation, such as copper plating, air cooling, and water cooling. However, since heat is generated inside the material, external auxiliary heat dissipation cannot dissipate the heat generated inside the material in a timely manner. Therefore, improving the thermal conductivity of metal soft magnetic composite materials is particularly important. Summary of the Invention

[0005] To address the technical problems existing in the prior art, the present invention provides a method for preparing a sandwich-structured, high thermal conductivity sheet-like metal soft magnetic composite material. By constructing a thermally conductive path, rapid heat conduction is achieved, thereby improving the heat dissipation capability of high-frequency integrated inductors.

[0006] The technical solution adopted in this invention is as follows:

[0007] A method for preparing a sandwich-structured, highly thermally conductive sheet-like soft magnetic metal composite material includes the following steps:

[0008] Step 1: Prepare nano-MnZn ferrite powder with extremely wide temperature range and ultra-low loss;

[0009] Step 2: Phosphate the flaky FeSiAl powder to obtain phosphated flaky FeSiAl powder;

[0010] Step 3: Add phosphated flake FeSiAl powder, nano MnZn ferrite powder, thermal conductive material and polyvinyl butyral (PVB) powder in anhydrous ethanol at a mass ratio of 1:0.01:0.05:0.18, and stir to obtain a slurry; wherein, the thermal conductive material is composed of flake graphene oxide (GO) dispersion and nano aluminum nitride (AlN);

[0011] Step 4: After vacuum degassing, the slurry is cast into a film and dried to obtain a composite film;

[0012] Step 5: Cut the composite film into a ring shape, heat and cure it, and then stack and press it into a ring-shaped sample to obtain a sandwich structure of high thermal conductivity sheet-like metal soft magnetic composite material, which is suitable for the preparation of high frequency integrated inductors.

[0013] Furthermore, the particle size D of the nano-MnZn ferrite powder 50 The average aspect ratio of the flake-shaped FeSiAl powder is 43.08, the flake-shaped GO has a diameter of 50-200 nm, and the particle size D of the nano-AlN is 150 nm. 50 It is 100 nm.

[0014] Furthermore, the specific preparation process of the nano-MnZn ferrite powder described in step 1 is as follows:

[0015] Step 1.1: Calculate and weigh the raw materials according to the main components of 52.7 mol% Fe2O3, 11.6 mol% ZnO and 35.7 mol% MnO, ball mill at 241 rpm for 2 h, and pre-calcine at 900 ℃ for 1 h to obtain pre-calcined material;

[0016] Step 1.2: Based on the mass of the pre-fired material, weigh 0.03 wt% CaO, 0.01 wt% Sb2O3, 0.01 wt% HfO2 and 0.015 wt% ZrO2 as auxiliary components, add them to the pre-fired material, ball mill at 241 rpm for 2 h, pre-fire at 1250 ℃ for 2 h, and sieve to obtain mixed powder;

[0017] Step 1.3: Ball mill the mixed powder to its particle size D. 50 The nanometer size was 150 nm, resulting in nano-MnZn ferrite powder.

[0018] Furthermore, the magnetic properties of the nano-MnZn ferrite powder described in step 1 are as follows: high permeability of up to 3500, and loss of less than 420 kW / m under conditions of -40℃, 100 kHz, and 200 mT. 3 The loss is less than 230 kW / m under the conditions of 25℃, 100 kHz, and 200 mT. 3 The loss is less than 340 kW / m under the conditions of 160℃, 100 kHz, and 200 mT. 3 .

[0019] Furthermore, the specific process of the phosphating treatment described in step 2 is as follows:

[0020] Prepare a phosphoric acid solution with a concentration of 0.25~2.5 wt%, add the flake FeSiAl powder to the phosphoric acid solution and phosphate for 30 min to form a phosphoric acid passivation layer, thereby obtaining the phosphated flake FeSiAl powder.

[0021] Furthermore, the flake GO dispersion in step 3 is obtained by dispersing flake GO in anhydrous ethanol.

[0022] Furthermore, in step 3, the mass ratio of the sheet-like GO dispersion to the nano-AlN in the thermally conductive material is 1~3:1~3.

[0023] Furthermore, the mass of anhydrous ethanol in the slurry described in step 3 is twice the mass of the phosphated flaky FeSiAl powder.

[0024] Furthermore, the stirring speed in step 3 is 400 rpm, and the duration is 8 h.

[0025] Furthermore, the vacuum degassing process described in step 4 lasts for 30 minutes.

[0026] Furthermore, in step 4, the casting speed is 10 cm / min, and the temperature of the casting machine chamber is 30 ℃.

[0027] Furthermore, the heating and curing temperature in step 5 is 90 ℃, and the holding time is 2 h; the pressing pressure is 20 MPa, and the holding time is 15 min.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. This invention proposes a method for preparing a sandwich-structured, high thermal conductivity sheet-like soft magnetic composite material. It employs a mixed thermally conductive system of sheet-like GO and nano-AlN, forming a thermally conductive layer on the surface of sheet-like FeSiAl powder, thus creating a sandwich structure of thermally conductive layer-magnetic material layer-thermally conductive layer. The sheet-like GO not only improves the thermal conductivity of the composite material but also helps reduce eddy current losses. Because the oxygen-containing functional groups of the sheet-like GO form hydrogen bonds with PVB molecules, they restrict the evaporation path of anhydrous ethanol solvent, inducing the formation of pores. Nano-AlN fills these pores, further enhancing the thermal conductivity of the composite material. Thus, through the synergistic effect of sheet-like GO and nano-AlN, a high thermal conductivity pathway is constructed within the composite material, enabling rapid heat conduction. This method improves the thermal conductivity of the soft magnetic composite material with less thermally conductive filler, enhancing its heat dissipation capacity.

[0030] 2. This invention uses ultra-wide temperature range and ultra-low loss soft magnetic nano-MnZn ferrite powder, which improves the permeability of the metal soft magnetic composite material while reducing hysteresis loss.

[0031] 3. This invention utilizes the shear force provided during the casting process to more tightly adhere the sheet-like GO-nano AlN mixed thermally conductive layer to the surface of the sheet-like FeSiAl metal powder. This allows the thermally conductive layer to tightly wrap the surface of the metal powder, thereby reducing the thermal resistance of the powder contact surface and the thermal resistance of the binder, improving the thermal conductivity and heat dissipation capacity of the composite material, and solving the heat dissipation problem of the material from the inside. Attached Figure Description

[0032] Figure 1 A schematic diagram of the simulation of the magnetic core surface temperature of the integrated inductor built using the sheet-like soft magnetic composite material obtained in Comparative Example 1.

[0033] Figure 2 This is a simulation diagram of the magnetic core surface temperature of an integrated inductor constructed using the sandwich structure of the high thermal conductivity sheet-like soft magnetic metal composite material obtained in Example 1. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0035] Comparative Example 1

[0036] This comparative example prepared a sheet-like metal soft magnetic composite material, specifically including the following steps:

[0037] Step 1: Add 3 g of phosphoric acid to 200 g of deionized water, stir evenly, then add 100 g of flaky FeSiAl powder with an average aspect ratio of 43.08, stir for 30 min, filter and dry to obtain phosphated flaky FeSiAl powder.

[0038] Step 2: Weigh 50 g of phosphated flaky FeSiAl powder and 9 g of PVB solid powder, add 100 g of anhydrous ethanol, and stir for 8 h to obtain a uniform and stable slurry.

[0039] Step 3: Place the slurry in a defoamer and vacuum defoam for 30 minutes;

[0040] Step 4: Cast the slurry into a film using a casting machine. Set the casting speed to 10 cm / min and the drying temperature to 30 ℃ to obtain a composite film.

[0041] Step 5: Cut the composite film into a ring shape, heat and cure it, and then stack and press it into a ring-shaped sample. The heating temperature is 90℃, the holding time is 2 h, the forming pressure is 20 MPa, and the holding time is 15 min, thus obtaining a sheet-like metal soft magnetic composite material.

[0042] Example 1

[0043] This embodiment prepares a sandwich-structured, highly thermally conductive sheet-like soft magnetic metal composite material, specifically including the following steps:

[0044] Step 1: Prepare nano-MnZn ferrite powder with extremely wide temperature range and ultra-low loss, specifically as follows:

[0045] Step 1.1: Calculate and weigh the raw materials according to the main components of 52.7 mol% Fe2O3, 11.6 mol% ZnO and 35.7 mol% MnO, ball mill at 241 rpm for 2 h, and pre-calcine at 900 ℃ for 1 h to obtain pre-calcined material;

[0046] Step 1.2: Based on the mass of the pre-fired material, weigh 0.03 wt% CaO, 0.01 wt% Sb2O3, 0.01 wt% HfO2 and 0.015 wt% ZrO2 as auxiliary components, add them to the pre-fired material, ball mill at 241 rpm for 2 h, pre-fire at 1250 ℃ for 2 h, and sieve to obtain mixed powder;

[0047] Step 1.3: Ball mill the mixed powder to a particle size of 150 nm to obtain nano-MnZn ferrite powder;

[0048] Step 2: Add 3 g of phosphoric acid to 200 g of deionized water, stir evenly, then add 100 g of flaky FeSiAl powder with an average aspect ratio of 43.08, stir for 30 min, filter and dry to obtain phosphated flaky FeSiAl powder.

[0049] Step 3: Add 50 g of phosphated flake FeSiAl powder, 9 g of PVB solid powder, 0.5 g of nano-MnZn ferrite powder, 0.625 g of flake GO dispersion, and 1.875 g of nano-AlN to 100 g of anhydrous ethanol, and stir for 8 h to obtain a uniform and stable slurry; wherein, the flake GO dispersion is obtained by dispersing flake GO with a particle size of 50 ~ 200 nm in anhydrous ethanol; the particle size D of nano-AlN is... 50 100 nm;

[0050] Step 4: Place the slurry in a defoamer and vacuum defoam for 30 minutes;

[0051] Step 5: Cast the slurry into a film using a casting machine. Set the casting speed to 10 cm / min and the drying temperature to 30 ℃ to obtain a composite film.

[0052] Step 6: Cut the composite film into a ring shape, heat and cure it, and then stack and press it into a ring-shaped sample. The heating temperature is 90℃, the holding time is 2 h, the forming pressure is 20 MPa, and the holding time is 15 min, thus obtaining a sandwich structure high thermal conductivity sheet-like metal soft magnetic composite material.

[0053] Example 2

[0054] This embodiment prepares a sandwich-structured, highly thermally conductive sheet-like soft magnetic metal composite material. The preparation process is the same as in Example 1, except that the "0.625 g sheet-like GO dispersion and 1.875 g nano-AlN" in step 3 is changed to "1.25 g sheet-like GO dispersion and 1.25 g nano-AlN"; the other steps remain unchanged.

[0055] Example 3

[0056] This embodiment prepares a sandwich-structured, highly thermally conductive sheet-like soft magnetic metal composite material. The preparation process is the same as that in Example 1, except that "0.625 g of sheet-like GO dispersion and 1.875 g of nano-AlN" in step 3 is changed to "1.875 g of sheet-like GO dispersion and 0.625 g of nano-AlN"; the other steps remain unchanged.

[0057] Comparative Example 2

[0058] This comparative example prepared a sheet-like metal soft magnetic composite material. The preparation process was the same as that in Example 1, except that "0.625 g of sheet-like GO dispersion and 1.875 g of nano-AlN" in step 3 was changed to "2.5 g of nano-AlN"; the other steps remained the same.

[0059] Comparative Example 3

[0060] This comparative example prepared a sheet-like metal soft magnetic composite material. The preparation process was the same as that in Example 1, except that "0.625 g of sheet-like GO dispersion and 1.875 g of nano-AlN" in step 3 was changed to "2.5 g of sheet-like GO dispersion"; the other steps remained the same.

[0061] The magnetic losses of the metal soft magnetic composite material samples prepared in Comparative Examples 1-3 and Examples 1-3 were tested using a SY-8218 BH analyzer under the following conditions: 25 °C, 5 MHz, 5 mT. The resistivity was tested using an LCR digital bridge, and the thermal conductivity was tested using a DRL-V thermal conductivity meter. The test results are shown in Table 1.

[0062] Table 1 Performance of Comparative and Example Samples

[0063]

[0064] As shown in Table 1, in Examples 1-3, the addition of 5% (by total mass) of thermally conductive material (sheet GO dispersion + nano-AlN) to the phosphated sheet FeSiAl powder slightly increased the loss of the soft magnetic composite material, but significantly improved the thermal conductivity. For example, in Example 1, the thermal conductivity increased by 19.5%, but the loss only increased by 6.7%. Furthermore, the composite material of the mixed thermally conductive system of sheet GO and nano-AlN showed better loss and thermal conductivity than the composite material using only sheet GO, and better resistivity than the composite material using only nano-AlN, resulting in improved overall performance.

[0065] Based on the performance parameters of the FeSiAl soft magnetic composite material in Comparative Example 1 and Example 1, an integrated inductor model was built using Ansys Maxwell simulation software. The ambient temperature was set to 25 ℃, and a sinusoidal excitation voltage of 1 V was used for thermal simulation at a frequency of 5 MHz. The simulation results are as follows: Figure 1 and Figure 2 As shown.

[0066] according to Figure 1 As shown, when the thermal conductivity of the material is 4.583 W / (m·K), the highest surface temperature of the magnetic core during operation of the integrated inductor is 26.710 ℃, with a temperature rise of 1.710 ℃; according to Figure 2As shown, when the thermal conductivity of the material is 5.479 W / (m·K), the highest surface temperature of the magnetic core during operation of the integrated inductor is 26.392 ℃, representing a temperature increase of 1.392 ℃. Compared to Comparative Example 1, the temperature rise is relatively reduced by 18.6%, demonstrating excellent heat dissipation performance.

[0067] It should be noted that this is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for producing a high thermal conductive, laminated, sheet-like metal soft magnetic composite material, characterized in that Includes the following steps: Step 1: Prepare nano-MnZn ferrite powder with extremely wide temperature range and ultra-low loss; Step 2: Phosphate the flaky FeSiAl powder to obtain phosphated flaky FeSiAl powder; Step 3: Add phosphated flake FeSiAl powder, nano MnZn ferrite powder, thermally conductive material and PVB powder in anhydrous ethanol at a mass ratio of 1:0.01:0.05:0.18, and stir to obtain a slurry; wherein, the thermally conductive material is composed of flake GO dispersion and nano AlN. Step 4: After vacuum degassing, the slurry is cast into a film and dried to obtain a composite film; Step 5: Cut the composite film into a ring shape, heat and cure it, and then stack and press it into a ring-shaped sample to obtain a sandwich structure of high thermal conductivity sheet-like metal soft magnetic composite material, which is suitable for the preparation of high frequency integrated inductors.

2. The method for preparing the sandwich-structured, high thermal conductivity sheet-like soft magnetic metal composite material according to claim 1, characterized in that, The particle size D of the nano-MnZn ferrite powder is 150 nm 50 The average diameter-thickness ratio of the flaky FeSiAl powder is 43.08, the flake diameter of the flaky GO is 50-200 nm, and the particle size D of the nano-AlN is 100 nm. 50 The particle size D of the nano-MnZn ferrite powder is 150 nm 3. The method for preparing the sandwich-structured, high thermal conductivity sheet-like soft magnetic metal composite material according to claim 2, characterized in that, The specific preparation process of the nano-MnZn ferrite powder in step 1 is as follows: Step 1.1: Calculate and weigh the raw materials according to the main components of 52.7 mol% Fe2O3, 11.6 mol% ZnO and 35.7 mol% MnO, ball mill at 241 rpm for 2 h, and pre-calcine at 900 ℃ for 1 h to obtain pre-calcined material; Step 1.2: Based on the mass of the pre-fired material, weigh 0.03 wt% CaO, 0.01 wt% Sb2O3, 0.01 wt% HfO2 and 0.015 wt% ZrO2 as auxiliary components, add them to the pre-fired material, ball mill at 241 rpm for 2 h, pre-fire at 1250 ℃ for 2 h, and sieve to obtain mixed powder; Step 1.3, the mixed powder is ball milled to its particle size D 50 is 150 nm, obtaining nano-MnZn ferrite powder.

4. The method for preparing the sandwich-structured, high thermal conductivity sheet-like soft magnetic metal composite material according to claim 2, characterized in that, The specific process of the phosphating treatment in step 2 is as follows: Prepare a phosphoric acid solution with a concentration of 0.25~2.5 wt%, add the flake FeSiAl powder to the phosphoric acid solution and phosphate for 30 min to form a phosphoric acid passivation layer, thereby obtaining the phosphated flake FeSiAl powder.

5. The method for preparing the sandwich-structured, high thermal conductivity sheet-like soft magnetic metal composite material according to claim 2, characterized in that, In step 3, the flake GO dispersion is obtained by dispersing flake GO in anhydrous ethanol.

6. The method for preparing the sandwich-structured, high thermal conductivity sheet-like soft magnetic metal composite material according to claim 5, characterized in that, In step 3, the mass ratio of the sheet-like GO dispersion to the nano-AlN in the thermally conductive material is 1~3:1~3.

7. The method for preparing the sandwich-structured, high thermal conductivity sheet-like soft magnetic metal composite material according to claim 2, characterized in that, The mass of anhydrous ethanol in the slurry described in step 2 is twice the mass of the phosphated flaky FeSiAl powder.

8. The method for preparing the sandwich-structured, high thermal conductivity sheet-like soft magnetic metal composite material according to claim 2, characterized in that, The casting speed in step 4 is 10 cm / min, and the temperature of the casting machine chamber is 30 ℃.

9. The method for preparing the sandwich-structured, high thermal conductivity sheet-like soft magnetic metal composite material according to claim 2, characterized in that, The heating and curing temperature in step 5 is 90 ℃, and the holding time is 2 h; the pressing pressure is 20 MPa, and the holding time is 15 min.

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