Silsesquioxane coated amorphous soft magnetic material with low dielectric property and preparation method of silsesquioxane coated amorphous soft magnetic material

Abstract

The invention discloses a silsesquioxane-coated amorphous soft magnetic material with low dielectric property and a preparation method of the silsesquioxane-coated amorphous soft magnetic material. The surface of an amorphous powder material is coated with silsesquioxane in situ through an emulsion polymerization method. By introducing the silsesquioxane coating layer, the dielectric constant of the material can be obviously reduced, the resistivity of the material can be improved, and the method is simple, convenient to operate, uniform in coating, good in coating layer stability and capable of achieving industrialization and has a great application prospect in the field of inductance high frequency.

Description

Technical Field

[0001] The 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] Nowadays, miniaturization, micro-miniaturization and high frequency of electronic products have become the mainstream of development, and the performance requirements for inductors, which are the main components of electronic products, are getting higher and higher. Since the amorphous powder used as the raw material for inductor manufacturing has a high dielectric constant, low resistivity and poor stability, the inductor made of it will cause the integrated circuit to heat up due to the high dielectric constant. At the same time, due to the low resistivity, it will cause losses when working in an alternating magnetic field. This loss causes the powder core to heat up under high frequency conditions, resulting in poor electromagnetic conversion effect. Coating and insulating the surface of amorphous powder can reduce such effects. Coating methods are divided into organic coating and inorganic coating. Organic coating materials are mainly materials such as phenolic resin and epoxy resin. Due to the low melting point, the coating layer formed has poor heat resistance and poor chemical stability. Inorganic coating materials are mainly materials such as non-magnetic oxides and phosphates. Although inorganic coating has good insulation and thermal stability, it requires complex high-temperature treatment during preparation, and it is easy to break during the pressing process due to loose coating. At the same time, the coating layer formed has low strength and heavy weight, and it is impossible to achieve lightweight inductors. Therefore, the insulating films prepared by the above methods cannot achieve the desired effect. Summary of the invention

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

[0004] In order to achieve the purpose, the present invention adopts the following technical scheme:

[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 is as follows: 100-500g of amorphous powder, 5-30% of the amorphous powder by weight of a silane coupling agent, and 0-2g of a surfactant are added into 200-500mL of a solvent and stirred to form an emulsion, and then 2-10g of ammonia water is added and stirred to react for 8-10h, the obtained product is washed with a solvent to remove unreacted silane coupling agent and surfactant, and then dried and ground and sieved to obtain the silsesquioxane-coated amorphous soft magnetic material.

[0008] Further, the surfactant used is one of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, Tween-80, Span-80 and hexadecyltrimethylammonium 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 as follows:

[0014] The present invention uses silsesquioxane coated amorphous powder material generated by in-situ polymerization. As a nano-scale silane material, silsesquioxane has Si-O-Si bonds to form an inorganic core, and the top silicon atom is modified with an organic functional group. The entire molecular structure is stable, low in density, light in weight, and not easy to shrink and deform. It has the advantages of excellent heat resistance, good chemical stability, high modulus, and good dielectric properties. The introduction of the silsesquioxane coating layer can significantly reduce the dielectric constant of the material, and the dielectric constant is stable and frequency-free at high temperatures. At the same time, the introduction of the silsesquioxane coating layer can also significantly increase the resistivity of the material, reduce the eddy current loss of the material, reduce the possibility of heating of the integrated circuit, and improve the electromagnetic conversion ability of the powder material. The method of the present invention is simple, easy to operate, uniformly coated, and has good coating 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 3The dielectric constant diagram of the amorphous soft magnetic materials prepared 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 curves of the amorphous soft magnetic materials prepared in various embodiments and comparative examples vary 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 detailed implementation methods and specific operation processes are given, 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 amorphous powder (Fe-Si-BC amorphous powder, micron spherical morphology, average particle size of 10μm), 5% of the amorphous powder mass of KH-590, 0.013g sodium dodecylbenzene sulfonate were added to 200mL ethanol and stirred vigorously at 1300rpm to form an emulsion, and then 2g of ammonia water was added and stirred for 10h. The obtained product was washed with ethanol several times, dried at 50℃ for 5h, and ground through a 500-mesh sieve to obtain a silsesquioxane-coated amorphous soft magnetic material.

[0024] The silsesquioxane-coated amorphous soft magnetic material and 2% epoxy resin of the powder material mass were added to acetone and stirred thoroughly to volatilize the acetone, and then passed through an 80-mesh stainless steel sieve and left for 8 hours to remove the remaining solvent. The material was pressed into a magnetic ring with a 10-ton pressure, and then the magnetic ring was cured at 180°C for 3 hours to obtain 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 amorphous powder (Fe-Si-BC amorphous powder, micron spherical morphology, average particle size of 10μm), KH-590 accounting for 10% of the amorphous powder, 0.013g sodium dodecylbenzene sulfonate were added to 200mL ethanol and stirred vigorously at 1300rpm to form an emulsion, and then 2g ammonia water was added and stirred for 10h. The obtained product was washed with ethanol several times, dried at 50℃ for 5h, and ground through a 500-mesh sieve to obtain a silsesquioxane-coated amorphous soft magnetic material.

[0028] The silsesquioxane-coated amorphous soft magnetic material and 2% epoxy resin of the powder material mass were added to acetone and stirred thoroughly to volatilize the acetone, and then passed through an 80-mesh stainless steel sieve and left for 8 hours to remove the remaining solvent. The material was pressed into a magnetic ring with a 10-ton pressure, and then the magnetic ring was cured at 180°C for 3 hours to obtain 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 amorphous powder (Fe-Si-BC amorphous powder, micron spherical morphology, average particle size of 10μm), KH-590 accounting for 20% of the amorphous powder, 0.013g sodium dodecylbenzene sulfonate were added to 200mL ethanol and stirred vigorously at 1300rpm to form an emulsion, and then 2g ammonia water was added and stirred for 10h. The obtained product was washed with ethanol several times, dried at 50℃ for 5h, and ground through a 500-mesh sieve to obtain a silsesquioxane-coated amorphous soft magnetic material.

[0032] The silsesquioxane-coated amorphous soft magnetic material and 2% epoxy resin of the powder material mass were added to acetone and stirred thoroughly to volatilize the acetone, and then passed through an 80-mesh stainless steel sieve and left for 8 hours to remove the remaining solvent. The material was pressed into a magnetic ring with a 10-ton pressure, and then the magnetic ring was cured at 180°C for 3 hours to obtain 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 amorphous powder (Fe-Si-BC amorphous powder, micron spherical morphology, average particle size of 10μm), KH-590 accounting for 30% of the amorphous powder, 0.013g sodium dodecylbenzene sulfonate were added to 200mL ethanol and stirred vigorously at 1300rpm to form an emulsion, and then 2g ammonia water was added and stirred for 10h. The obtained product was washed with ethanol several times, dried at 50℃ for 5h, and ground through a 500-mesh sieve to obtain a silsesquioxane-coated amorphous soft magnetic material.

[0036] The silsesquioxane-coated amorphous soft magnetic material and 2% epoxy resin of the powder material mass were added to acetone and stirred thoroughly to volatilize the acetone, and then passed through an 80-mesh stainless steel sieve and left for 8 hours to remove the remaining solvent. The material was pressed into a magnetic ring with a 10-ton pressure, and then the magnetic ring was cured at 180°C for 3 hours to obtain a toroidal inductor for testing.

[0037] Comparative Example 1

[0038] Amorphous powder (Fe-Si-BC amorphous powder, micron spherical morphology, average particle size of 10μm) and epoxy resin accounting for 2% of the powder mass were added to acetone and stirred thoroughly to volatilize the acetone, then passed through an 80-mesh stainless steel sieve and left for 8 hours to remove the remaining solvent. The material was pressed into a magnetic ring with a 10-ton pressure, and then the magnetic ring was cured at 180°C for 3 hours to obtain a toroidal inductor for comparison.

[0039] Figure 1 This is a 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-configuration silicon oxide 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 with the increase of the silsesquioxane coating amount, the dielectric constant of the sample is constantly increasing. 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% has a high frequency (1*10 7 Hz) increased by 76.6% compared with the uncoated control group, reducing the eddy current loss of the material and improving the electromagnetic conversion efficiency.

[0044] The above description is only 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 should be included in the protection scope 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 of silsesquioxane on the surface of the amorphous powder material by 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: 100-500g of amorphous powder, 5-30% of the mass of the amorphous powder, and 0-2g of a surfactant are added to 200-500mL of a solvent and stirred to form an emulsion, and then 2-10g of ammonia water is added and stirred to react for 8-10h. The obtained product is washed with a solvent to remove unreacted silane coupling agent and surfactant, dried, ground and sieved to obtain silsesquioxane-coated amorphous soft magnetic material.

4. The preparation method according to claim 3, characterized in that: The surfactant is one of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, Tween-80, Span-80 and hexadecyltrimethylammonium bromide.

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

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

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

8. The preparation method according to claim 3, characterized in that: The sieving adopts a stainless steel screen with meshes of 80 to 500.

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