A nanocrystalline composite material, a preparation method and application thereof

Abstract

The application belongs to the technical field of magnetic material preparation, and particularly relates to a nanocrystalline composite material, a preparation method and application. The preparation method comprises the following steps: (1) mixing FeNi material with silane coupling agent, and obtaining pretreated FeNi material after one-time annealing; wherein the temperature of the one-time annealing is 650-750 DEG C, and the time is 0.5-2 h; (2) mixing the pretreated FeNi material obtained in the step (1) with FeSiNbBCu nanocrystalline to obtain a mixture, and then compressing and performing secondary annealing. The nanocrystalline composite material prepared by the method has high magnetic permeability and low loss in the medium frequency range of 300-3000 kHz.

Description

Technical Field

[0001] This invention belongs to the field of magnetic material preparation technology, specifically relating to a nanocrystalline composite material, its preparation method, and its application. Background Technology

[0002] Both nanocrystalline and iron-nickel materials are magnetic powder core materials, widely used in filters, transformers, inductors, capacitors, magnetic devices, medicine, aerospace, and other fields. Compared with traditional magnetic materials, the particle size of nanocrystalline and iron-nickel materials is closer to the magnetic domain size, resulting in lower hysteresis and eddy current losses. They can efficiently convert energy at high frequencies, possess high saturation magnetic induction, enabling designs with small size and high power density. They also exhibit good stability over a wide temperature range, maintaining high magnetic properties at high temperatures and covering a wide frequency range, meeting application requirements from low to high frequencies. With technological advancements and in-depth research, nanocrystalline and iron-nickel materials are expected to play an even greater role in future applications. Current techniques for preparing magnetic materials by mixing nanocrystalline and iron-nickel powders are relatively complex and suitable for low-frequency ranges below 300kHz. When applied to the mid-frequency range of 300-3000kHz, they exhibit higher losses and lower permeability. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defects of magnetic powder cores in the medium frequency range, such as high loss and low permeability, so as to provide a nanocrystalline composite material, its preparation method and application.

[0004] To this end, the present invention provides the following technical solution.

[0005] This invention provides a method for preparing nanocrystalline composite materials, comprising the following steps:

[0006] (1) FeNi material is mixed with silane coupling agent and then annealed once to obtain pretreated FeNi material; wherein, the temperature of the first annealing is 650-750℃ and the time is 0.5-2h;

[0007] (2) The pretreated FeNi material obtained in step (1) is mixed with FeSiNbBCu nanocrystals to obtain a mixture, which is then pressed and annealed twice.

[0008] The heating rate for the first annealing is 1-5℃ / min.

[0009] In step (1), the silane coupling agent includes at least one of vinyltriethoxysilane, trifluoropropyltriethoxysilane, and phenyltriethoxysilane;

[0010] Preferably, the mass ratio of the FeNi material to the silane coupling agent is (90-110):(0.5-4).

[0011] The particle size D50 of the FeNi material is 10-20 μm.

[0012] In step (2), the mass ratio of the pretreated FeNi material obtained in step (1) to FeSiNbBCu nanocrystals is (3-7):(3-7).

[0013] The general formula of the FeSiNbBCu nanocrystals is Fe a Si b Nb c B d Cu e Where a is 62-89, b is 5-15, c is 5-15, d is 0.5-4, and e is 0.5-4;

[0014] The particle size D50 of the FeSiNbBCu nanocrystals is 10-20 μm.

[0015] The pressing pressure is 10-15 T / cm. 2 ;

[0016] Preferably, the secondary annealing temperature is 550-650℃, the time is 0.5-4h, and the heating rate is 1-5℃ / min.

[0017] Step (2) further includes adding at least one of a silane coupling agent and a binder to the mixture before pressing;

[0018] Preferably, the silane coupling agent is at least one selected from vinyltriethoxysilane, trifluoropropyltriethoxysilane, and phenyltriethoxysilane;

[0019] Preferably, the amount of the silane coupling agent added is 0.5-1 wt% of the mixture;

[0020] Preferably, the adhesive is at least one selected from epoxy resin, phenolic resin, silicone resin, polyester resin and PVB;

[0021] Preferably, the amount of the binder added is 1-1.5 wt% of the mixture.

[0022] The present invention also provides a nanocrystalline composite material prepared by the above preparation method.

[0023] The present invention also provides an electronic inductor device comprising the nanocrystalline composite material prepared by the above-described preparation method.

[0024] The technical solution of this invention has the following advantages:

[0025] 1. The present invention provides a method for preparing nanocrystalline composite materials, comprising: (1) mixing FeNi material with a silane coupling agent and annealing it once to obtain pretreated FeNi material; wherein the temperature of the first annealing is 650-750℃ and the time is 0.5-2h; (2) mixing the pretreated FeNi material obtained in step (1) with FeSiNbBCu nanocrystals to obtain a mixture, pressing it, and annealing it a second time. The nanocrystalline composite material prepared by this method has high permeability and low loss in the mid-frequency range of 300-3000kHz. Adding a silane coupling agent to FeNi materials can prevent agglomeration, improve dispersibility and stability, enhance surface energy, and improve the magnetic permeability and loss performance of FeNi materials. Further annealing the FeNi material mixed with the silane coupling agent removes internal stress, resulting in more uniform and finer grain sizes in the nanocrystalline composite material, thus improving its magnetic permeability and reducing losses. Annealing temperatures below 650℃ lead to inconsistent grain sizes and poor grain size uniformity; annealing temperatures above 750℃ cause abnormal grain growth, which also reduces grain size uniformity. Uniform grain size helps improve the densification effect during annealing, shortens particle spacing, lowers the annealing temperature, reduces porosity and defects, improves the magnetic permeability of the composite material, and reduces losses. This nanocrystalline composite material can be used in transformers, instrument transformers, filter inductors, switching power supplies, photovoltaic inverters, etc.

[0026] 2. The method for preparing nanocrystalline composite materials provided by the present invention can further balance loss performance and magnetic permeability by controlling the amount of iron-nickel material and FeSiNbBCu nanocrystals. If the amount of iron-nickel material is too large, the magnetic permeability will increase but it will affect the loss performance. When the amount of nanocrystals is increased, the loss will be reduced but the magnetic permeability will be affected.

[0027] 3. The preparation method of the nanocrystalline composite material provided by this invention involves annealing the iron-nickel material and the silane coupling agent at 650-750℃ once, which allows the iron-nickel material to fully exert its performance and gives the composite material high magnetic permeability. A second annealing at 550-650℃ allows the FeSiNbBCu nanocrystals to achieve their higher loss performance, resulting in a composite material with low loss. This ensures that the composite material possesses both high magnetic permeability and low loss. However, excessively high second annealing temperatures can negatively impact the performance of the FeSiNbBCu nanocrystals. Detailed Implementation

[0028] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0029] Where specific experimental steps or conditions are not specified in the examples, they can be performed according to the conventional experimental steps or conditions described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0030] To address the shortcomings of existing magnetic powder core materials in achieving both low loss and high permeability in the mid-frequency range, this invention provides the following technical solution.

[0031] In a first aspect, the present invention provides a method for preparing a nanocrystalline composite material, comprising the following steps:

[0032] (1) FeNi material is mixed with silane coupling agent and then annealed once to obtain pretreated FeNi material; wherein, the temperature of the first annealing is 650-750℃ and the time is 0.5-2h;

[0033] (2) The pretreated FeNi material obtained in step (1) is mixed with FeSiNbBCu nanocrystals to obtain a mixture, which is then pressed and annealed twice.

[0034] This invention first adds a silane coupling agent to the iron-nickel material and then performs a first annealing to prevent agglomeration, improve dispersibility and stability, enhance surface energy, increase magnetic permeability, and reduce losses. If the first annealing temperature is too low, it will affect the grain size and uniformity; if it is too high, it will cause abnormal grain growth and reduce uniformity. Improving the uniformity of grain size helps to enhance the densification effect of the annealing process, thereby increasing magnetic permeability and reducing losses.

[0035] As an example, the temperature for one annealing step is 650℃, 660℃, 670℃, 680℃, 690℃, 700℃, 710℃, 720℃, 730℃, 740℃, 750℃, or any combination of two values. The annealing time for one annealing step is 0.5h, 0.8h, 1h, 1.3h, 1.6h, 2h, or any combination of two values.

[0036] As an optional implementation, the heating rate for the first annealing is 1-5°C / min. For example, the heating rate can be 1°C / min, 2°C / min, 3°C / min, 4°C / min, 5°C / min, or any combination of two of these values.

[0037] As an optional implementation, in step (1), the silane coupling agent includes at least one of vinyltriethoxysilane, trifluoropropyltriethoxysilane, and phenyltriethoxysilane;

[0038] Preferably, the mass ratio of the FeNi material to the silane coupling agent is (90-110):(0.5-4). As an example, the mass ratio of the FeNi material to the silane coupling agent is 90:0.5, 95:0.5, 100:0.5, 105:0.5, 110:0.5, 90:1, 90:2, 90:3, 100:1, 100:3, 105:2, 105:4, or any range of two such values.

[0039] As an optional implementation, the particle size D50 of the FeNi material is 10-20 μm.

[0040] As an optional implementation, in step (2), the mass ratio of the pretreated FeNi material obtained in step (1) to the FeSiNbBCu nanocrystals is (3-7):(3-7). As an example, the mass ratio of the pretreated FeNi material obtained in step (1) to the FeSiNbBCu nanocrystals is 1:1, 3:5, 3:7, 4:7, 5:3, 5:7, 6:3, 6:7, 7:3, or any range of two values.

[0041] As an optional implementation, the FeSiNbBCu nanocrystals have the general formula Fe. a Si b Nb c B d Cu e Where a is 62-89, b is 5-15, c is 5-15, d is 0.5-4, and e is 0.5-4.

[0042] It should be noted that a%, b%, c%, d%, and e% are the mass percentages of each element, and a + b + c + d + e = 100.

[0043] The particle size D50 of the FeSiNbBCu nanocrystals is 10-20 μm;

[0044] As an optional implementation, the pressing pressure is 10-15 T / cm. 2 ;

[0045] Preferably, the secondary annealing temperature is 550-650℃, the time is 0.5-4h, and the heating rate is 1-5℃ / min.

[0046] It should be noted that excessively high secondary annealing temperatures can affect the performance of FeSiNbBCu nanocrystals. A first annealing of the iron-nickel material and silane coupling agent at 650-750℃ allows the iron-nickel material to fully utilize its properties, resulting in a composite material with high magnetic permeability. A second annealing at 550-650℃ then allows the FeSiNbBCu nanocrystals to achieve their higher loss characteristics, resulting in a composite material with low loss. This ensures that the composite material combines the advantages of high magnetic permeability and low loss.

[0047] As an optional implementation, step (2) further includes adding at least one of a silane coupling agent and a binder to the mixture before pressing;

[0048] Preferably, the silane coupling agent is at least one selected from vinyltriethoxysilane, trifluoropropyltriethoxysilane, and phenyltriethoxysilane;

[0049] Preferably, the amount of the silane coupling agent added is 0.5-1 wt% of the mixture;

[0050] Preferably, the adhesive is at least one selected from epoxy resin, phenolic resin, silicone resin, polyester resin and PVB;

[0051] Preferably, the amount of the binder added is 1-1.5 wt% of the mixture.

[0052] Secondly, the present invention provides a nanocrystalline composite material prepared by the above method.

[0053] Thirdly, the present invention provides an electronic inductor device comprising the nanocrystalline composite material prepared by the above method. It should be noted that, as is known in the art, electronic inductor devices include transformers, current transformers, filter inductors, switching power supplies, photovoltaic inverters, etc.

[0054] Example 1

[0055] This embodiment provides a method for preparing nanocrystalline composite materials, including the following steps:

[0056] (1) Iron-nickel material with D50 of 15 μm was mixed with vinyltriethoxysilane coupling agent at a mass ratio of 100:1. Under nitrogen atmosphere, the mixture was heated to 720℃ at a heating rate of 3℃ / min and held for 1h for annealing to obtain pretreated iron-nickel material.

[0057] (2) Pretreated iron-nickel materials and Fe with a D50 of 15μm 83Si8Nb7B1Cu1 nanocrystals were mixed at a mass ratio of 1:1 to obtain a mixture. Zirconium balls (20 wt% of the mixture) were added, and the mixture was dry-milled for 10 minutes. Nitrogen gas was purged throughout the process to prevent oxidation caused by heat generated during milling. Trifluoropropyltriethoxysilane coupling agent (0.5 wt% of the mixture) was added to anhydrous ethanol to prepare a mixture, which was then added to the milled mixture and milled for another 15 minutes. The mixture was then drained until the anhydrous ethanol had completely evaporated and passed through a 100-mesh sieve. A binder solution was then added and stirred until the solvent evaporated, and then passed through a 60-mesh sieve. The binder was epoxy resin, and the solvent was acetone. The amount of epoxy resin binder added was 1 wt% of the mixture. The mixture was then subjected to a 12 T / cm... 2 The ring was pressed to obtain a ring; then, under a nitrogen atmosphere, the temperature was raised to 620℃ at a heating rate of 3℃ / min and held for 2 hours to obtain a nanocrystalline composite material.

[0058] Example 2

[0059] This embodiment provides a method for preparing a nanocrystalline composite material, which differs from Embodiment 1 in that the annealing temperature in this embodiment is 680℃.

[0060] Example 3

[0061] This embodiment provides a method for preparing nanocrystalline composite materials, which differs from Example 1 in that: the pretreated iron-nickel material in this embodiment is combined with Fe... 83 The mass ratio of Si8Nb7B1Cu1 nanocrystals is 7:3.

[0062] Example 4

[0063] This embodiment provides a method for preparing nanocrystalline composite materials, which differs from Example 1 in that: the pretreated iron-nickel material in this embodiment is combined with Fe... 83 The mass ratio of Si8Nb7B1Cu1 nanocrystals is 3:7.

[0064] Example 5

[0065] This embodiment provides a method for preparing a nanocrystalline composite material, which differs from Embodiment 1 in that: in step (2) of this embodiment, the amount of silane coupling agent added is 1 wt% of the mixture.

[0066] Example 6

[0067] This embodiment provides a method for preparing a nanocrystalline composite material, which differs from Embodiment 1 in that: in step (2) of this embodiment, the amount of silane coupling agent added is 0.8 wt% of the mixture.

[0068] Example 7

[0069] This embodiment provides a method for preparing nanocrystalline composite materials. The difference from Embodiment 1 is that the ball milling time after adding silane coupling agent in step (2) of this embodiment is 10 min, instead of 15 min in Embodiment 1.

[0070] Example 8

[0071] This embodiment provides a method for preparing nanocrystalline composite materials. The difference from Embodiment 1 is that the ball milling time after adding silane coupling agent in step (2) of this embodiment is 20 min, instead of 15 min in Embodiment 1.

[0072] Example 9

[0073] This embodiment provides a method for preparing nanocrystalline composite materials. The difference from Embodiment 1 is that the temperature of the secondary annealing in step (2) of this embodiment is 550°C.

[0074] Example 10

[0075] This embodiment provides a method for preparing nanocrystalline composite materials. The difference from Embodiment 1 is that the temperature of the secondary annealing in step (2) of this embodiment is 580°C.

[0076] Example 11

[0077] This embodiment provides a method for preparing nanocrystalline composite materials. The difference from Embodiment 1 is that the temperature of the secondary annealing in step (2) of this embodiment is 650°C.

[0078] Comparative Example 1

[0079] This comparative example provides a method for preparing a nanocrystalline composite material, which differs from Example 1 in that: this comparative example does not perform a first annealing treatment on the iron-nickel material, but directly combines it with Fe... 83 Si8Nb7B1Cu1 nanocrystal mixture.

[0080] Comparative Example 2

[0081] This comparative example provides a method for preparing a nanocrystalline composite material, which differs from Example 1 in that the annealing temperature in this comparative example is 640°C.

[0082] Comparative Example 3

[0083] This comparative example provides a method for preparing a nanocrystalline composite material, which differs from Example 1 in that the annealing temperature in this comparative example is 760°C.

[0084] Comparative Example 4

[0085] This comparative example provides a method for preparing a nanocrystalline composite material. The difference between this method and Example 1 is that in step (1) of this comparative example, no silane coupling agent is added when the iron-nickel material is annealed once.

[0086] Test case

[0087] The permeability and loss at 500 kHz / 50 Mt of the nanocrystalline composite materials prepared in each example and comparative example were tested using a WK-6500B analyzer and a SY-8218B-H analyzer, respectively. The results are shown in Table 1. The pretreated iron-nickel material obtained in Example 1 was used as control group 1, and the Fe raw material from Example 1 was used as control group 1. 83 Si8Nb7B1Cu1 nanocrystals served as control group 2.

[0088] Table 1. Test results for each embodiment and comparative example.

[0089]

[0090]

[0091] Based on the above results, this invention first adds a silane coupling agent to the iron-nickel material, then performs a first annealing at 650-750℃, and then mixes it with FeSiNbBCu nanocrystals. The resulting composite material after a second annealing exhibits both high permeability and low loss. Comparative Examples 1-3 show that directly mixing the iron-nickel material with FeSiNbBCu nanocrystals or using an excessively low first annealing temperature results in insufficient grain growth and crystallization, failing to completely eliminate internal stress and causing severe agglomeration. Excessively high first annealing temperatures lead to abnormal grain growth, affecting performance. Comparative Example 4 shows that without the addition of a silane coupling agent before the first annealing, the permeability decreases and the loss increases. This is because the silane coupling agent can enable particles to form an interactive structure, improving interfacial forces and bonding strength, increasing dispersion, and thus improving the material's permeability and loss performance. Control Groups 1-2 demonstrate that this invention, by combining the first-annealed iron-nickel material with FeSiNbBCu nanocrystals, can obtain a composite material that balances high permeability and low loss.

[0092] Based on the above results, the present invention can obtain composite materials with satisfactory performance under different ball milling times and different amounts of silane coupling agent. The magnetic permeability of the nanocrystalline composite material prepared by the present invention is not less than 50 H / m, and the loss is not higher than 900 mW / cm. 3 Based on the principle of cost reduction and efficiency improvement, this invention can obtain high-performance magnetic powder core composite materials in a shorter time and with a lower amount of silane coupling agent.

[0093] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a nanocrystalline composite material, characterized in that, Includes the following steps: (1) FeNi material is mixed with silane coupling agent and then annealed once to obtain pretreated FeNi material; wherein the temperature of the first annealing is 650-750℃ and the time is 0.5-2h; (2) The pretreated FeNi material obtained in step (1) is mixed with FeSiNbBCu nanocrystals to obtain a mixture, which is then pressed and annealed twice. The mass ratio of the FeNi material to the silane coupling agent is (90-110):(0.5-4).

2. The preparation method according to claim 1, characterized in that, The heating rate for the first annealing is 1-5℃ / min.

3. The preparation method according to claim 1 or 2, characterized in that, In step (1), the silane coupling agent includes at least one of vinyltriethoxysilane, trifluoropropyltriethoxysilane, and phenyltriethoxysilane.

4. The preparation method according to claim 1, characterized in that, The particle size D50 of the FeNi material is 10-20 μm.

5. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of the pretreated FeNi material obtained in step (1) to FeSiNbBCu nanocrystals is (3-7):(3-7).

6. The preparation method according to claim 1, characterized in that, The general formula of the FeSiNbBCu nanocrystals is Fe a Si b Nb c B d Cu e Where a is 62-89, b is 5-15, c is 5-15, d is 0.5-4, and e is 0.5-4.

7. The preparation method according to claim 1, characterized in that, The particle size D50 of the FeSiNbBCu nanocrystals is 10-20 μm.

8. The preparation method according to claim 1, characterized in that, The pressing pressure is 10-15 T / cm. 2 .

9. The preparation method according to claim 1, characterized in that, The secondary annealing temperature is 550-650℃, the time is 0.5-4h, and the heating rate is 1-5℃ / min.

10. The preparation method according to claim 1, characterized in that, Step (2) further includes adding at least one of a silane coupling agent and a binder to the mixture before pressing.

11. The preparation method according to claim 1, characterized in that, The silane coupling agent is at least one of vinyltriethoxysilane, trifluoropropyltriethoxysilane, and phenyltriethoxysilane.

12. The preparation method according to claim 10, characterized in that, The amount of the silane coupling agent added is 0.5-1 wt% of the mixture.

13. The preparation method according to claim 10, characterized in that, The adhesive is at least one of epoxy resin, phenolic resin, silicone resin, polyester resin and PVB.

14. The preparation method according to claim 10, characterized in that, The amount of the binder added is 1-1.5 wt% of the mixture.

15. The nanocrystalline composite material prepared by the preparation method according to any one of claims 1-14.

16. An electronic inductor device, characterized in that, Including the nanocrystalline composite material prepared by the preparation method according to any one of claims 1-14.

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