A silsesquioxane-coated amorphous soft magnetic material with low dielectric properties and a preparation method thereof

Abstract

This invention discloses a silsesquioxane-coated amorphous soft magnetic material with low dielectric properties and a preparation method thereof. The invention involves in-situ coating of the amorphous powder with silsesquioxane via emulsion polymerization. The introduction of the silsesquioxane coating significantly reduces the dielectric constant and increases the resistivity of the material. The method is simple, easy to operate, provides uniform coating, and exhibits good coating stability. It is amenable to industrialization and has great application prospects in the high-frequency field of inductors.

Description

Technical Field

[0001] The present invention belongs to the field of soft magnetic composite materials, and in particular relates to a silsesquioxane-coated amorphous soft magnetic material with low dielectric properties and a preparation method thereof. Background Art

[0002] Today, miniaturization, microfabrication, and high-frequency electronics are the mainstream of electronic product development, placing increasing demands on the performance of inductors, a key component of these products. Because amorphous powder, the raw material for inductor manufacturing, has a high dielectric constant, low resistivity, and poor stability, inductors made from it can cause heating in integrated circuits due to the high dielectric constant. Furthermore, its low resistivity results in losses when operating in alternating magnetic fields. This loss causes the powder core to heat up at high frequencies, resulting in poor electromagnetic conversion. Insulating the amorphous powder surface with a coating can mitigate these effects. Coating methods include organic and inorganic coatings. Organic coating materials, primarily phenolic resins and epoxy resins, have low melting points, resulting in coating layers with poor heat resistance and chemical stability. Inorganic coating materials, primarily non-magnetic oxides and phosphates, offer excellent insulation and thermal stability, but require complex high-temperature processing during preparation. Furthermore, loose coatings can easily break during pressing. Furthermore, the resulting coating layer is weak and heavy, making it difficult to achieve lightweight inductors. Therefore, the insulating films prepared by the above methods cannot achieve the ideal effect. Summary of the Invention

[0003] Based on the problems existing in the above-mentioned prior art, the present invention provides a silsesquioxane-coated amorphous soft magnetic material with low dielectric properties, aiming to obtain amorphous powder with low dielectric properties and high frequency resistance.

[0004] To achieve the purpose, the present invention adopts the following technical solutions:

[0005] A silsesquioxane-coated amorphous soft magnetic material with low dielectric properties is characterized in that the silsesquioxane-coated amorphous soft magnetic material is obtained by in-situ coating silsesquioxane on the surface of an amorphous powder material through an emulsion polymerization method.

[0006] Furthermore, the silsesquioxane is prepared using silane coupling agents such as KH-560, KH-580, KH-590, and ND-42 as raw materials.

[0007] The preparation method of the silsesquioxane-coated amorphous soft magnetic material of the present invention comprises the following steps: adding 100-500 g of amorphous powder, 5-30% of the amorphous powder by weight of a silane coupling agent, and 0-2 g of a surfactant to 200-500 mL of a solvent and stirring to form an emulsion; then adding 2-10 g of aqueous ammonia and stirring to react for 8-10 hours; washing the obtained product with a solvent to remove unreacted silane coupling agent and surfactant; drying the product, and grinding and sieving the product to obtain the silsesquioxane-coated amorphous soft magnetic material.

[0008] Furthermore, the surfactant used is one of sodium dodecylbenzenesulfonate, sodium lauryl sulfate, Tween-80, Span-80 and cetyltrimethylammonium bromide.

[0009] Furthermore, the solvent is at least one of ethanol and isopropanol.

[0010] Furthermore, the stirring speed is 1300-3000 rpm.

[0011] Furthermore, the drying temperature is 40-80° C. and the drying time is 4-6 hours.

[0012] Furthermore, the sieving uses a stainless steel screen with mesh sizes of 80 to 500.

[0013] Compared with the prior art, the beneficial effects of the present invention are embodied in:

[0014] The present invention uses silsesquioxane-coated amorphous powders generated by in-situ polymerization. Silsesquioxane, a nanoscale silane material, has an inorganic core formed by Si-O-Si bonds and organic functional groups modified on the apex silicon atoms. The entire molecular structure is stable, low in density, lightweight, and not susceptible to shrinkage and deformation. It has the advantages of excellent heat resistance, good chemical stability, high modulus, and good dielectric properties. The introduction of a silsesquioxane coating can significantly reduce the dielectric constant of the material, and the dielectric constant is stable and frequency-independent at high temperatures. Simultaneously, the introduction of a silsesquioxane coating can significantly increase the resistivity of the material, reduce the eddy current loss of the material, reduce the possibility of heat generation in integrated circuits, and improve the electromagnetic conversion capability of the powder. The method of the present invention is simple, easy to operate, uniformly coated, and has good coating layer stability. It can be industrialized and has great application prospects in the field of high-frequency inductors. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the SEM image of the silsesquioxane-coated amorphous soft magnetic material prepared in Example 1.

[0016] Figure 2 This is an infrared image of the silsesquioxane-coated amorphous soft magnetic material prepared in Example 1.

[0017] Figure 3Graphs showing the dielectric constants of the amorphous soft magnetic materials obtained in various embodiments and comparative examples.

[0018] Figure 4 This is a temperature-dependent dielectric constant diagram of the silsesquioxane-coated amorphous soft magnetic material prepared in Example 1.

[0019] Figure 5 The resistivity of the amorphous soft magnetic materials prepared in various embodiments and comparative examples varies with frequency. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is described in detail below through specific embodiments. The following embodiments are implemented on the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operating processes, but the protection scope of the present invention is not limited to the following embodiments.

[0021] Example 1

[0022] In this embodiment, the silsesquioxane-coated amorphous soft magnetic material is prepared according to the following steps:

[0023] 200g of amorphous powder (Fe-Si-BC amorphous powder, micron-spherical morphology, average particle size 10μm), 5% KH-590 (by weight), and 0.013g of sodium dodecylbenzenesulfonate were added to 200mL of ethanol and stirred vigorously at 1300rpm to form an emulsion. 2g of ammonia was then added and stirring continued for 10 hours. The resulting product was washed several times with ethanol, dried at 50°C for 5 hours, and ground through a 500-mesh sieve to obtain a silsesquioxane-coated amorphous soft magnetic material.

[0024] Silsesquioxane-coated amorphous soft magnetic material and 2% epoxy resin by weight of the powder were added to acetone and stirred thoroughly to evaporate the acetone. The mixture was then passed through an 80-mesh stainless steel sieve and allowed to stand for 8 hours to remove any remaining solvent. The material was then pressed into a magnetic ring using a 10-ton pressure and cured at 180°C for 3 hours to produce a toroidal inductor for testing.

[0025] Example 2

[0026] In this embodiment, the silsesquioxane-coated amorphous soft magnetic material is prepared according to the following steps:

[0027] 200g of amorphous powder (Fe-Si-BC amorphous powder, micron-spherical morphology, average particle size 10μm), KH-590 (10% by weight of the amorphous powder), and 0.013g of sodium dodecylbenzenesulfonate were added to 200mL of ethanol and stirred vigorously at 1300rpm to form an emulsion. 2g of aqueous ammonia was then added and stirring continued for 10 hours. The resulting product was washed several times with ethanol, dried at 50°C for 5 hours, and ground through a 500-mesh sieve to obtain a silsesquioxane-coated amorphous soft magnetic material.

[0028] Silsesquioxane-coated amorphous soft magnetic material and 2% epoxy resin by weight of the powder were added to acetone and stirred thoroughly to evaporate the acetone. The mixture was then passed through an 80-mesh stainless steel sieve and allowed to stand for 8 hours to remove any remaining solvent. The material was then pressed into a magnetic ring using a 10-ton pressure and cured at 180°C for 3 hours to produce a toroidal inductor for testing.

[0029] Example 3

[0030] In this embodiment, the silsesquioxane-coated amorphous soft magnetic material is prepared according to the following steps:

[0031] 200g of amorphous powder (Fe-Si-BC amorphous powder, micron-spherical morphology, average particle size 10μm), KH-590 (20% by weight of the amorphous powder), and 0.013g of sodium dodecylbenzenesulfonate were added to 200mL of ethanol and stirred vigorously at 1300rpm to form an emulsion. 2g of aqueous ammonia was then added and stirring continued for 10 hours. The resulting product was washed several times with ethanol, dried at 50°C for 5 hours, and ground through a 500-mesh sieve to obtain a silsesquioxane-coated amorphous soft magnetic material.

[0032] Silsesquioxane-coated amorphous soft magnetic material and 2% epoxy resin by weight of the powder were added to acetone and stirred thoroughly to evaporate the acetone. The mixture was then passed through an 80-mesh stainless steel sieve and allowed to stand for 8 hours to remove any remaining solvent. The material was then pressed into a magnetic ring using a 10-ton pressure and cured at 180°C for 3 hours to produce a toroidal inductor for testing.

[0033] Example 4

[0034] In this embodiment, the silsesquioxane-coated amorphous soft magnetic material is prepared according to the following steps:

[0035] 200g of amorphous powder (Fe-Si-BC amorphous powder, micron-spherical morphology, average particle size 10μm), KH-590 (30% by weight of the amorphous powder), and 0.013g of sodium dodecylbenzenesulfonate were added to 200mL of ethanol and stirred vigorously at 1300rpm to form an emulsion. 2g of ammonia water was then added and stirring continued for 10 hours. The resulting product was washed several times with ethanol, dried at 50°C for 5 hours, and ground through a 500-mesh sieve to obtain a silsesquioxane-coated amorphous soft magnetic material.

[0036] Silsesquioxane-coated amorphous soft magnetic material and 2% epoxy resin by weight of the powder were added to acetone and stirred thoroughly to evaporate the acetone. The mixture was then passed through an 80-mesh stainless steel sieve and allowed to stand for 8 hours to remove any remaining solvent. The material was then pressed into a magnetic ring using a 10-ton pressure and cured at 180°C for 3 hours to produce a toroidal inductor for testing.

[0037] Comparative Example 1

[0038] Amorphous powder (Fe-Si-BC amorphous powder, micron-spherical in shape, with an average particle size of 10 μm) and 2% epoxy resin by weight were added to acetone and stirred thoroughly. The acetone was evaporated, and the mixture was then passed through an 80-mesh stainless steel sieve and allowed to stand for 8 hours to remove any remaining solvent. The material was then pressed into a magnetic ring using a 10-ton pressure and then cured at 180°C for 3 hours to produce a comparative test toroidal inductor.

[0039] Figure 1 This is an SEM image of the silsesquioxane-coated amorphous soft magnetic material prepared in Example 1. It can be seen that the surface of the amorphous powder is evenly coated, and the product particle size is about 13 μm.

[0040] Figure 2 This is the infrared image of the silsesquioxane-coated amorphous soft magnetic material prepared in Example 1, at a wave number of 1025 cm -1 and 1074cm -1 The peak at [RSiO 1.5 ]xThis T-configured silica skeleton structure, 2605cm -1 The peak at is the peak of mercaptopropyl in the system, indicating that silsesquioxane is successfully coated on the magnetic powder.

[0041] Figure 3 The dielectric constant diagram of the amorphous soft magnetic materials prepared in each embodiment and comparative example shows that as the amount of silsesquioxane coating increases, the dielectric constant of the sample continues to increase. The dielectric constant of the sample with a coating amount of 30% at high frequency increases by 25% compared with the uncoated comparative example.

[0042] Figure 4 This is a temperature-dependent dielectric constant diagram of the silsesquioxane-coated amorphous soft magnetic material prepared in Example 1. It can be seen that the material has no frequency dependence at high temperatures, indicating that the powder material has high stability and good uniformity after coating.

[0043] Figure 5 The resistivity of the amorphous soft magnetic materials prepared in each embodiment and comparative example varies with frequency. It can be seen that the resistivity of the sample hardly changes at high frequency. The sample with a coating amount of 30% changes at high frequency (1*10 7 Hz) increased by 76.6% compared with the uncoated control, reducing the eddy current loss of the material and improving the electromagnetic conversion efficiency.

[0044] The above description is merely an exemplary embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A silsesquioxane-coated amorphous soft magnetic material with low dielectric properties, characterized in that: The silsesquioxane-coated amorphous soft magnetic material is prepared by in-situ coating silsesquioxane on the surface of an amorphous powder material through an emulsion polymerization method.

2. The silsesquioxane-coated amorphous soft magnetic material with low dielectric properties according to claim 1, characterized in that: The silsesquioxane is prepared by taking a silane coupling agent as a raw material.

3. A method for preparing the silsesquioxane-coated amorphous soft magnetic material according to claim 1 or 2, characterized in that: 100-500 g of amorphous powder, 5-30% of the weight of the amorphous powder, and 0-2 g of a surfactant are added to 200-500 mL of a solvent and stirred to form an emulsion. 2-10 g of ammonia water is then added and stirred to react for 8-10 hours. The resulting product is washed with a solvent to remove unreacted silane coupling agent and surfactant, dried, and then ground and sieved to obtain a silsesquioxane-coated amorphous soft magnetic material.

4. The preparation method according to claim 3, wherein: The surfactant is one of sodium dodecylbenzenesulfonate, sodium lauryl sulfate, Tween-80, Span-80 and cetyltrimethylammonium bromide.

5. The preparation method according to claim 3, wherein: The solvent is at least one of ethanol and isopropanol.

6. The preparation method according to claim 3, wherein: The stirring speed is 1300-3000 rpm.

7. The preparation method according to claim 3, wherein: The drying temperature is 40-80° C. and the drying time is 4-6 hours.

8. The preparation method according to claim 3, wherein: The sieving adopts 80-500 mesh stainless steel screen.

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