High-permeability soft magnetic ferrite core and manufacturing method thereof

Abstract

The invention relates to the technical field of magnetic materials, and particularly discloses a high-permeability soft magnetic ferrite core and a manufacturing method thereof.The mica powder provided by the invention is of a layered structure, mainly comprises SiO2 and Al2O3 and has high resistivity, then iron oxide and nickel oxide are loaded on the mica powder through a coprecipitation method, and the high-permeability soft magnetic ferrite core is obtained. The magnetic conductivity of mica powder is improved under the combined action of iron oxide and nickel oxide, then cocamidopropyl betaine is adopted for carrying out surface treatment on the composite mica powder, so that the functional filler has high surface activity and is easily adsorbed on the particle surfaces of all components of the soft magnetic ferrite core in the ball milling process, a wrapping film is formed, and the magnetic conductivity of the soft magnetic ferrite core is improved. The mica powder further contains Mn and Fe elements, the magnetic conductivity of the soft magnetic ferrite is further improved, SiO2 and Al2O3 in the mica powder form an insulating layer on a grain interface, high resistance is achieved, and the power loss of the soft magnetic ferrite is reduced while the high magnetic conductivity is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic materials, and particularly relates to a high-permeability soft ferrite magnetic core and a manufacturing method thereof. Background Art

[0002] Soft ferrite is a ferrimagnetic oxide with Fe 2 O 3 as the main component. Soft ferrite materials have been widely used in pillar industries and emerging industries such as computers, household appliances, energy-saving lamps and LEDs, network communication, automobiles and electric vehicles, high-speed railways, wind power and nuclear power generation. In the industrial production of soft ferrite, with the increasing trend of miniaturization and high frequency of electronic devices, higher requirements are put forward for the dimensional accuracy, mechanical strength and electromagnetic performance of magnetic cores.

[0003] At present, there are soft ferrite materials with Fe 2 O 3 , MnO and ZnO as the main components. Usually, a high-resistance substance is introduced at the grain boundaries of manganese-zinc ferrite. The high-resistivity substance existing at the grain boundaries can block high-frequency current and reduce magnetic loss. However, since the added high-resistivity substances are usually non-magnetic substances, the addition will dilute the magnetism of manganese-zinc ferrite, and especially reduce the permeability of manganese-zinc ferrite more significantly under high-frequency conditions.

[0004] Chinese Patent Document CN109704749A discloses a preparation method and application of an ultra-high-frequency low-loss soft ferrite material and magnetic core. The ultra-high-frequency low-loss soft ferrite material includes specific proportions of Fe 2 O 3 , Mn 3 O 4 , ZnO and additive components of specific types and proportions. Combining with the low-temperature sintering process and atmosphere protection, a magnetic core product with a power loss of 110 kW / m 3 or less under high-temperature and high-frequency conditions can be prepared as a whole, which is convenient for application in fields such as big data network switch servers, in-vehicle electronic digital modules, aerospace high-power power supplies, etc. However, the permeability of the prepared soft ferrite material still needs to be further improved. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a high-permeability soft ferrite magnetic core and a manufacturing method thereof.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A high-permeability soft ferrite magnetic core, comprising the following components in parts by weight: Fe 2 O 360 - 80 parts, MnO 20 - 30 parts, ZnO 8 - 12 parts, Mo 2 O 3 0.01 - 0.02 parts, SiO 2 0.015 - 0.025 parts, CoO 0.03 - 0.04 parts, ZrO 2 0.005 - 0.01 parts, CaCO 3 0.01 - 0.02 parts, functional filler 0.2 - 0.4 parts.

[0008] In the technical solution disclosed in the present invention, Mo 2 O 3 is used in soft magnetic ferrites to improve the high - frequency performance of the material and reduce losses.

[0009] In the technical solution disclosed in the present invention, SiO 2 is mainly used as an insulator and stabilizer in soft magnetic ferrites, which can improve the mechanical strength and temperature stability of the material, and at the same time reduce grain growth.

[0010] In the technical solution disclosed in the present invention, CoO is used to improve the magnetic permeability and high - frequency performance of soft magnetic ferrites.

[0011] In the technical solution disclosed in the present invention, ZrO 2 is used to improve the mechanical properties and temperature stability of soft magnetic ferrites.

[0012] In the technical solution disclosed in the present invention, CaCO 3 is mainly used as a sintering aid in soft magnetic ferrites. Calcium ions can promote the sintering process, improve the density of the material, and thus improve the magnetic properties of the material.

[0013] In the technical solution disclosed in the present invention, the preparation method of the functional filler is as follows:

[0014] S1. Grind and sieve mica powder, then ultrasonically disperse it in deionized water. Then add soluble iron salt and soluble nickel salt to it, stir and mix evenly, adjust the pH of the solution to 11 - 12, heat it in a water bath for reaction. After the reaction is completed, evaporate and concentrate the reaction solution, and dry, calcine, grind and sieve the obtained solid product to obtain composite mica powder;

[0015] S2. Disperse the composite mica powder in deionized water, then add cocamidopropyl betaine to it, heat and stir. Then place it in a drying oven to dry the water, grind and sieve it to obtain the functional filler.

[0016] Specifically, in step S1, the mass ratio of the mica powder, soluble iron salt and soluble nickel salt is 5-10:3-6:3-6. For example, 5:3:3, 5:4:3, 5:3:5, 5:3:6, 8:4:4, 8:4:6, 10:5:5, 10:6:6 can be selected, but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0017] Preferably, the soluble iron salt is selected from ferric nitrate, ferric sulfate or ferric chloride.

[0018] Preferably, the soluble nickel salt is selected from nickel nitrate or nickel chloride.

[0019] Specifically, in step S1, the temperature of the water bath heating reaction is 60-80 °C. For example, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C can be selected; the time of the water bath heating reaction is 2-4 h. For example, 2 h, 2.5 h, 3 h, 3.5 h, 4 h can be selected, but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0020] Specifically, in step S1, the calcination temperature is 500-600 °C. For example, 500 °C, 520 °C, 550 °C, 580 °C, 600 °C can be selected; the calcination time is 2-4 h. For example, 2 h, 2.5 h, 3 h, 3.5 h, 4 h can be selected, but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0021] Specifically, in step S2, the mass ratio of the composite mica powder and cocamidopropyl betaine is 1:1-1.2. For example, 1:1, 1:1.1, 1:1.2 can be selected, but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0022] Specifically, in step S2, the temperature of the heating and stirring treatment is 50-60 °C. For example, 50 °C, 51 °C, 52 °C, 53 °C, 54 °C, 55 °C, 56 °C, 57 °C, 58 °C, 59 °C, 60 °C can be selected; the time of the heating and stirring treatment is 3-5 h. For example, 3 h, 3.5 h, 4 h, 4.5 h, 5 h can be selected, but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0023] The present invention also provides a manufacturing method of the above high magnetic permeability soft ferrite magnetic core, including the following steps:

[0024] (1) Wet ball mill and mix Fe 2 O 3 , MnO and ZnO according to the formula amount to obtain a mixed material;

[0025] (2) Dry the mixed material and then perform pre-calcination to obtain a pre-calcined material;

[0026] (3) Grind the presintered material and sieve it, then add Mo to the presintered material. 2 O 3 , SiO 2 , CoO, ZrO 2 , CaCO 3 and functional fillers, and perform ball milling treatment to obtain powder materials.

[0027] (4) Add an adhesive to the powder materials, stir evenly, and then put them into a mold and press them into green body samples.

[0028] (5) Place the green body samples in a reaction furnace, adjust the oxygen partial pressure of the reaction furnace, in a nitrogen atmosphere with an oxygen volume content of 0.08% - 0.1%, first heat up at a rate of 5 - 10 °C / min to 650 - 700 °C, and keep the temperature for 30 - 60 min; in a nitrogen atmosphere with an oxygen volume content of 3% - 5%, then heat up at a rate of 3 - 5 °C / min to 1250 - 1300 °C, and the sintering holding time is 2 - 3 h; after sintering, cool down to room temperature at a rate of 5 - 10 °C / min in a nitrogen atmosphere with an oxygen volume content of 0.08% - 0.1% to obtain a high magnetic permeability soft ferrite magnetic core.

[0029] Specifically, in step (1), deionized water with the same mass as the added materials is added during wet ball milling, the rotation speed of the ball mill is 250 - 300 rpm, and the ball milling time is 6 - 8 h.

[0030] Specifically, in step (2), the presintering temperature is 700 - 850 °C, for example, 700 °C, 720 °C, 750 °C, 780 °C, 800 °C, 820 °C, 840 °C, 850 °C can be selected; the presintering heating rate is 3 - 5 °C / min, for example, 3 °C / min, 4 °C / min, 5 °C / min can be selected; the presintering holding time is 1 - 2 h, for example, 1 h, 1.5 h, 2 h can be selected; but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0031] Specifically, in step (3), the rotation speed of the ball mill during ball milling treatment is 250 - 300 rpm, and the ball milling time is 4 - 6 h.

[0032] Specifically, in step (4), the mass of the adhesive is 0.4 - 0.8% of the mass of the powder materials, for example, 0.4%, 0.5%, 0.6%, 0.7%, 0.8% can be selected, and the adhesive is selected from polyvinyl alcohol.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The mica powder provided by the present invention has a layered structure, and its main components are SiO 2 and Al2 O 3 , having a relatively high resistivity. Then, through the coprecipitation method, iron oxide and nickel oxide are loaded on mica powder. The combined action of iron oxide and nickel oxide improves the magnetic permeability of the mica powder. Subsequently, coconut amide propyl betaine is used to treat the surface of the composite mica powder, making the functional filler have a relatively high surface activity. During the ball milling process, it is easy to adsorb on the particle surfaces of each component of the soft magnetic ferrite core to form a coating film. The applicant found during the experiment that mica powder has a better effect than montmorillonite. The reason may be that mica powder also contains a small amount of Mn and Fe elements, thereby improving the magnetic permeability of the soft magnetic ferrite. The SiO 2 and Al 2 O 3 form an insulating layer at the grain boundaries, having high resistivity, reducing the power loss of the soft magnetic ferrite while ensuring high magnetic permeability.

[0035] (2) For the soft magnetic ferrite core provided by the present invention, through specific element ratios and manufacturing processes, the loss of the core in high-frequency applications is significantly reduced. And by adding functional fillers, it is ensured that the core has a relatively high magnetic permeability, which can meet the requirements of various electronic devices for magnetic permeability. Moreover, the manufacturing method provided by the present invention is simple and efficient, suitable for large-scale production. Detailed Embodiments

[0036] The present invention will be further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.

[0037] It should be noted that unless otherwise specified, the chemical reagents involved in the present invention are all purchased through commercial channels.

[0038] The mica powder selected in the embodiments of the present invention is sericite, purchased from Chuzhou Wanqiao Sericite Co., Ltd., wherein the content of SiO 2 is 50 - 55%, the content of Al 2 O 3 is 26 - 30%, and the content of K 2 O is 7 - 9.5%.

[0039] Example 1

[0040] A manufacturing method of a high magnetic permeability soft magnetic ferrite core includes the following steps:

[0041] (1) Add 60 parts of Fe 2 O 3 , 20 parts of MnO, 8 parts of ZnO, and 68 parts of deionized water into a ball mill, and perform wet ball milling and mixing at a rotation speed of 300 rpm for 6 h to obtain a mixture.

[0042] (2) Dry the mixture and then pre-burn it at a heating rate of 5 °C / min, a pre-burning temperature of 700 °C, and a pre-burning holding time of 1 h to obtain pre-burned material.

[0043] (3) Grind the pre-burned material through a 200-mesh sieve, and then add 0.01 part of Mo 2 O 3 , 0.02 part of SiO 2 , 0.03 part of CoO, 0.005 part of ZrO 2 , 0.02 part of CaCO 3 and 0.2 part of functional filler, and perform ball milling. The rotation speed of the ball mill is 300 rpm, and the ball milling time is 4 h to obtain powder;

[0044] Among them, the preparation method of the functional filler is as follows:

[0045] S1. Grind and pulverize 8 g of mica powder through a 400-mesh sieve, then ultrasonically disperse it in 100 mL of deionized water, and then add 4 g of iron nitrate and 4 g of nickel nitrate thereto, stir and mix evenly, adjust the pH of the solution to 12, and perform a water bath heating reaction at 60 °C for 4 h. After the reaction is completed, evaporate and concentrate the reaction solution, dry the obtained solid product, calcine it at 500 °C for 4 h, and grind it through a 400-mesh sieve to obtain composite mica powder;

[0046] S2. Disperse 5 g of composite mica powder in 100 mL of deionized water, then add 5 g of cocamidopropyl betaine thereto, perform a heating and stirring treatment at 50 °C for 5 h, then place it in a drying oven to dry the water, and grind it through a 400-mesh sieve to obtain the functional filler.

[0047] (4) Add the adhesive polyvinyl alcohol to the powder. The addition amount of polyvinyl alcohol is 0.5% of the powder mass, stir evenly, then put it into a mold, and keep it at a pressure of 8 MPa for 5 min to press it into a green body sample.

[0048] (5) Place the green body sample in a reaction furnace, adjust the oxygen partial pressure of the reaction furnace, in a nitrogen atmosphere with an oxygen volume content of 0.1%, first heat it at a rate of 10 °C / min to 650 °C and hold for 40 min; in a nitrogen atmosphere with an oxygen volume content of 3%, then heat it at a rate of 5 °C / min to 1250 °C, and the sintering holding time is 2 h; after sintering, cool it to room temperature at a rate of 10 °C / min in a nitrogen atmosphere with an oxygen volume content of 0.1% to obtain a high magnetic permeability soft magnetic ferrite core.

[0049] Example 2

[0050] A manufacturing method of a high magnetic permeability soft magnetic ferrite core, comprising the following steps:

[0051] (1) Mix 80 parts of Fe 2O 3 30 parts of MnO, 12 parts of ZnO, and 122 parts of deionized water were added to a ball mill and wet ball milled for 6 h at a rotation speed of 300 rpm to obtain a mixed material.

[0052] (2) The mixed material was dried and then pre-fired at a heating rate of 5 °C / min, a pre-firing temperature of 800 °C, and a pre-firing holding time of 1 h to obtain a pre-fired material.

[0053] (3) The pre-fired material was ground through a 200-mesh sieve, and then 0.02 parts of Mo 2 O 3 0.025 parts of SiO 2 2, 0.04 parts of CoO, 0.01 parts of ZrO 2 2, 0.02 parts of CaCO 3 3, and 0.4 parts of functional filler were ball milled at a rotation speed of 300 rpm for 4 h to obtain a powder material;

[0054] Among them, the preparation method of the functional filler is as follows:

[0055] S1. 5 g of mica powder was ground and pulverized through a 400-mesh sieve, then ultrasonically dispersed in 100 mL of deionized water, and then 3 g of iron nitrate and 3 g of nickel nitrate were added thereto, stirred and mixed evenly, the pH of the solution was adjusted to 12, and the reaction was carried out in a water bath at 80 °C for 2 h. After the reaction was completed, the reaction solution was evaporated and concentrated, and the obtained solid product was dried and calcined at 500 °C for 4 h and ground through a 400-mesh sieve to obtain composite mica powder;

[0056] S2. 5 g of composite mica powder was dispersed in 100 mL of deionized water, and then 6 g of cocamidopropyl betaine was added thereto, and the mixture was heated and stirred at 50 °C for 5 h, and then placed in a drying oven to dry the water and ground through a 400-mesh sieve to obtain the functional filler.

[0057] (4) Polyvinyl alcohol as an adhesive was added to the powder material, and the addition amount of polyvinyl alcohol was 0.5% of the mass of the powder material, stirred evenly, then put into a mold, and held at a pressure of 8 MPa for 5 min to be pressed into a green body sample.

[0058] (5) The green body sample was placed in a reaction furnace, the oxygen partial pressure of the reaction furnace was adjusted, and in a nitrogen atmosphere with an oxygen volume content of 0.1%, it was first heated to 650 °C at a rate of 10 °C / min and held for 40 min; in a nitrogen atmosphere with an oxygen volume content of 3%, it was then heated to 1250 °C at a rate of 5 °C / min, and the sintering holding time was 2 h; after sintering, it was cooled to room temperature at a rate of 10 °C / min in a nitrogen atmosphere with an oxygen volume content of 0.1% to obtain a high magnetic permeability soft ferrite magnetic core.

[0059] Example 3

[0060] A manufacturing method of a soft magnetic ferrite core with high magnetic permeability, comprising the following steps:

[0061] (1) Add 70 parts of Fe 2 O 3 , 25 parts of MnO, 10 parts of ZnO and 105 parts of deionized water into a ball mill, and carry out wet ball milling and mixing at a rotation speed of 300 rpm for 6 h to obtain a mixed material.

[0062] (2) Dry the mixed material and then carry out pre-sintering. The heating rate is 5 °C / min, the pre-sintering temperature is 850 °C, and the pre-sintering holding time is 1 h to obtain a pre-sintered material.

[0063] (3) Grind the pre-sintered material through a 200-mesh sieve, and then add 0.015 parts of Mo 2 O 3 , 0.015 parts of SiO 2 , 0.035 parts of CoO, 0.005 parts of ZrO 2 , 0.015 parts of CaCO 3 and 0.3 parts of functional filler, and carry out ball milling treatment. The rotation speed of the ball mill is 300 rpm, and the ball milling time is 4 h to obtain a powder material;

[0064] Among them, the preparation method of the functional filler is as follows:

[0065] S1. Grind 10 g of mica powder and crush it through a 400-mesh sieve, then ultrasonically disperse it in 100 mL of deionized water, then add 6 g of iron nitrate and 6 g of nickel nitrate thereto, stir and mix evenly, adjust the pH of the solution to 12, heat and react in a water bath at 80 °C for 2 h. After the reaction is completed, evaporate and concentrate the reaction solution, dry the obtained solid product, calcine it at 500 °C for 4 h, and grind it through a 400-mesh sieve to obtain composite mica powder;

[0066] S2. Disperse 5 g of composite mica powder in 100 mL of deionized water, then add 5.5 g of cocamidopropyl betaine thereto, heat and stir at 60 °C for 3 h, then place it in a drying oven to dry the water, and grind it through a 400-mesh sieve to obtain the functional filler.

[0067] (4) Add the adhesive polyvinyl alcohol to the powder material. The addition amount of polyvinyl alcohol is 0.5% of the mass of the powder material, stir evenly, then put it into a mold, and keep it at a pressure of 8 MPa for 5 min to press into a green body sample.

[0068] (5) Place the green sample in a reaction furnace, adjust the oxygen partial pressure of the reaction furnace, in a nitrogen atmosphere with an oxygen volume content of 0.1%, first heat it at a rate of 10 °C / min to 650 °C and hold for 40 min; in a nitrogen atmosphere with an oxygen volume content of 3%, then heat it at a rate of 5 °C / min to 1250 °C, and the sintering holding time is 2 h; after sintering, cool it to room temperature at a rate of 10 °C / min in a nitrogen atmosphere with an oxygen volume content of 0.1%, and a high magnetic permeability soft magnetic ferrite core is obtained.

[0069] Comparative Example 1

[0070] A manufacturing method of a high magnetic permeability soft magnetic ferrite core includes the following steps:

[0071] (1) Add 60 parts of Fe 2 O 3 , 20 parts of MnO, 8 parts of ZnO, and 68 parts of deionized water into a ball mill, and carry out wet ball milling and mixing for 6 h at a rotation speed of 300 rpm to obtain a mixed material.

[0072] (2) After drying the mixed material, carry out pre-sintering, the heating rate is 5 °C / min, the pre-sintering temperature is 700 °C, and the pre-sintering holding time is 1 h to obtain a pre-sintered material.

[0073] (3) Grind the pre-sintered material through a 200-mesh sieve, and then add 0.01 part of Mo 2 O 3 , 0.02 part of SiO 2 , 0.03 part of CoO, 0.005 part of ZrO 2 , 0.02 part of CaCO 3 and 0.2 part of functional filler, carry out ball milling treatment, the rotation speed of the ball mill is 300 rpm, and the ball milling time is 4 h to obtain a powder;

[0074] Among them, the preparation method of the functional filler is as follows:

[0075] S1. Grind and pulverize 8 g of mica powder through a 400-mesh sieve, then ultrasonically disperse it in 100 mL of deionized water, then add 4 g of ferric nitrate to it, stir and mix evenly, adjust the pH of the solution to 12, carry out a water bath heating reaction at 60 °C for 4 h, after the reaction is completed, evaporate and concentrate the reaction solution, dry the obtained solid product, calcine it at 500 °C for 4 h, and grind it through a 400-mesh sieve to obtain composite mica powder;

[0076] S2. Disperse 5 g of composite mica powder in 100 mL of deionized water, then add 5 g of cocamidopropyl betaine to it, carry out heating and stirring treatment at 50 °C for 5 h, then place it in a drying oven to dry the water, and grind it through a 400-mesh sieve to obtain the functional filler.

[0077] (4) Add polyvinyl alcohol, an adhesive, to the powder material. The addition amount of polyvinyl alcohol is 0.5% of the mass of the powder material. Stir evenly, then put it into a mold, and keep it under a pressure of 8 MPa for 5 min to press into a green body sample.

[0078] (5) Place the green body sample in a reaction furnace, adjust the oxygen partial pressure of the reaction furnace. In a nitrogen atmosphere with an oxygen volume content of 0.1%, first heat it at a rate of 10 °C / min to 650 °C and keep it warm for 40 min; in a nitrogen atmosphere with an oxygen volume content of 3%, then heat it at a rate of 5 °C / min to 1250 °C, and the sintering holding time is 2 h; after sintering, cool it to room temperature at a rate of 10 °C / min in a nitrogen atmosphere with an oxygen volume content of 0.1% to obtain a high magnetic permeability soft magnetic ferrite core.

[0079] Compared with Example 1, in Comparative Example 1, nickel oxide was not loaded on mica powder.

[0080] Comparative Example 2

[0081] A manufacturing method of a high magnetic permeability soft magnetic ferrite core, comprising the following steps:

[0082] (1) Add 60 parts of Fe 2 O 3 , 20 parts of MnO, 8 parts of ZnO, and 68 parts of deionized water into a ball mill, and carry out wet ball milling and mixing at a rotation speed of 300 rpm for 6 h to obtain a mixed material.

[0083] (2) Dry the mixed material and then carry out pre-sintering. The heating rate is 5 °C / min, the pre-sintering temperature is 700 °C, and the pre-sintering holding time is 1 h to obtain a pre-sintered material.

[0084] (3) Grind the pre-sintered material through a 200-mesh sieve, and then add 0.01 part of Mo 2 O 3 , 0.02 part of SiO 2 , 0.03 part of CoO, 0.005 part of ZrO 2 , 0.02 part of CaCO 3 and 0.2 part of functional filler, and carry out ball milling treatment. The rotation speed of the ball mill is 300 rpm, and the ball milling time is 4 h to obtain a powder material;

[0085] Among them, the preparation method of the functional filler is as follows:

[0086] 8 g of mica powder was ground and pulverized through a 400-mesh sieve, then ultrasonically dispersed in 100 mL of deionized water. Subsequently, 4 g of iron nitrate and 4 g of nickel nitrate were added thereto, and the mixture was stirred and mixed evenly. The pH of the solution was adjusted to 12, and the reaction was carried out in a water bath at 60 °C for 4 h. After the reaction was completed, the reaction solution was evaporated and concentrated, and the obtained solid product was dried and calcined at 500 °C for 4 h and then ground through a 400-mesh sieve to obtain the functional filler.

[0087] (4) Polyvinyl alcohol as an adhesive was added to the powder material, and the addition amount of polyvinyl alcohol was 0.5% of the mass of the powder material. After stirring evenly, it was put into a mold and kept at a pressure of 8 MPa for 5 min to be pressed into a green body sample.

[0088] (5) The green body sample was placed in a reaction furnace, and the oxygen partial pressure of the reaction furnace was adjusted. In a nitrogen atmosphere with an oxygen volume content of 0.1%, it was first heated to 650 °C at a rate of 10 °C / min and kept warm for 40 min; in a nitrogen atmosphere with an oxygen volume content of 3%, it was then heated to 1250 °C at a rate of 5 °C / min, and the sintering and heat preservation time was 2 h; after sintering, it was cooled to room temperature at a rate of 10 °C / min in a nitrogen atmosphere with an oxygen volume content of 0.1% to obtain the high magnetic permeability soft ferrite magnetic core.

[0089] Compared with Example 1, in Comparative Example 2, coconut amide propyl betaine was not used for surface treatment.

[0090] Comparative Example 3

[0091] A manufacturing method of a high magnetic permeability soft ferrite magnetic core includes the following steps:

[0092] (1) 60 parts of Fe 2 O 3 , 20 parts of MnO, 8 parts of ZnO and 68 parts of deionized water were added to a ball mill and wet ball milled and mixed at a rotation speed of 300 rpm for 6 h to obtain a mixed material.

[0093] (2) After the mixed material was dried, it was pre-calcined. The heating rate was 5 °C / min, the pre-calcination temperature was 700 °C, and the pre-calcination heat preservation time was 1 h to obtain a pre-calcined material.

[0094] (3) The pre-calcined material was ground through a 200-mesh sieve, and then 0.01 part of Mo 2 O 3 , 0.02 part of SiO 2 , 0.03 part of CoO, 0.005 part of ZrO 2 , 0.02 part of CaCO 3 and 0.2 part of the functional filler were added to the pre-calcined material and ball milled. The rotation speed of the ball mill was 300 rpm, and the ball milling time was 4 h to obtain a powder material;

[0095] Among them, the preparation method of the functional filler is as follows:

[0096] S1. Grind 8 g of montmorillonite, pulverize it, and sieve it through a 400-mesh sieve. Then, ultrasonically disperse it in 100 mL of deionized water. Next, add 4 g of iron nitrate and 4 g of nickel nitrate to it, stir and mix evenly, adjust the pH of the solution to 12, heat and react it in a water bath at 60 °C for 4 h. After the reaction is completed, evaporate and concentrate the reaction solution, dry the obtained solid product, calcine it at 500 °C for 4 h, and grind it through a 400-mesh sieve to obtain composite montmorillonite;

[0097] S2. Disperse 5 g of the composite montmorillonite in 100 mL of deionized water, then add 5 g of cocamidopropyl betaine to it, heat and stir it at 50 °C for 5 h. Subsequently, place it in a drying oven to dry the water, grind it through a 400-mesh sieve, and thus obtain the functional filler.

[0098] (4) Add the adhesive polyvinyl alcohol to the powder material. The addition amount of polyvinyl alcohol is 0.5% of the mass of the powder material. Stir evenly, then put it into a mold, and keep it under a pressure of 8 MPa for 5 min to press it into a green body sample.

[0099] (5) Place the green body sample in a reaction furnace, adjust the oxygen partial pressure of the reaction furnace. In a nitrogen atmosphere with an oxygen volume content of 0.1%, first heat it at a rate of 10 °C / min to 650 °C and keep it warm for 40 min; in a nitrogen atmosphere with an oxygen volume content of 3%, then heat it at a rate of 5 °C / min to 1250 °C, and the sintering and holding time is 2 h; after sintering, cool it to room temperature at a rate of 10 °C / min in a nitrogen atmosphere with an oxygen volume content of 0.1%, and thus obtain a soft magnetic ferrite core with high magnetic permeability.

[0100] In Comparative Example 3 compared with Example 1, montmorillonite is used to replace mica powder.

[0101] Perform performance tests on the soft magnetic ferrite cores prepared in Example 1 and Comparative Examples 1 - 3. The results are shown in Table 1.

[0102] Table 1 Statistical table of performance test results

[0103]

[0104] It can be seen from the table that by comparing Example 1 and Comparative Examples 1 - 3, the soft magnetic ferrite core prepared by the present invention has the characteristics of low loss and high magnetic permeability.

[0105] Finally, it should be noted that: the above embodiments do not limit the present invention in any form. For those skilled in the art, based on the present invention, some modifications and improvements can be made to it. Therefore, any modification or improvement made without departing from the spirit of the present invention falls within the scope of protection required by the present invention.

Claims

1. A high permeability soft ferrite core, characterized in that: The invention comprises the following components in parts by weight: 60-80 parts of Fe2O3, 20-30 parts of MnO, 8-12 parts of ZnO, 0.01-0.02 parts of Mo2O3, 0.015-0.025 parts of SiO2, 0.03-0.04 parts of CoO, 0.005-0.01 parts of ZrO2, 0.01-0.02 parts of CaCO3 and 0.2-0.4 parts of functional filler.

2. The high permeability soft ferrite core according to claim 1, characterized in that: The preparation method of the functional filler is as follows: S1, grinding and sieving the mica powder, then ultrasonically dispersing it in deionized water, then adding soluble iron salt and soluble nickel salt thereto, stirring and mixing evenly, adjusting the pH of the solution to 11-12, heating in a water bath to react, after the reaction is completed, evaporating and concentrating the reaction solution, drying, calcining, grinding and sieving the obtained solid product to obtain a composite mica powder; S2. Dispersing the composite mica powder in deionized water, then adding cocamidopropyl betaine thereto, heating and stirring, then placing in a drying oven to dry the water, grinding and sieving, and obtaining a functional filler.

3. The high permeability soft ferrite core according to claim 2, characterized in that: In step S1, the mass ratio of the mica powder, the soluble iron salt and the soluble nickel salt is 5-10:3-6:3-6.

4. The high permeability soft ferrite core according to claim 2, characterized in that: In step S1, the soluble iron salt is selected from ferric nitrate, ferric sulfate or ferric chloride.

5. The high permeability soft ferrite core according to claim 2, characterized in that: In step S1, the soluble nickel salt is selected from nickel nitrate or nickel chloride.

6. The high permeability soft ferrite core according to claim 2, characterized in that: In step S1, the temperature of the water bath heating reaction is 60-80° C., and the time of the water bath heating reaction is 2-4 hours.

7. The high permeability soft ferrite core according to claim 2, characterized in that: In step S2, the mass ratio of the composite mica powder to cocamidopropyl betaine is 1:1-1.

2.

8. The high permeability soft ferrite core according to claim 2, characterized in that: In step S2, the temperature of the heating and stirring treatment is 50-60°C, and the time of the heating and stirring treatment is 3-5h.

9. The method for manufacturing a high permeability soft ferrite core according to any one of claims 1 to 8, characterized in that: The steps include: (1) Fe2O3, MnO and ZnO are wet-milled and mixed according to the formula amount to obtain a mixture; (2) drying the mixed material and pre-burning it to obtain a pre-burned material; (3) grinding and sieving the pre-sintered material, then adding Mo2O3, SiO2, CoO, ZrO2, CaCO3 and functional fillers to the pre-sintered material, and ball milling to obtain powder; (4) Adding an adhesive to the powder, stirring evenly, and then placing it into a mold and pressing it into a green sample; (5) placing the green sample in a reactor, adjusting the oxygen partial pressure of the reactor, first heating to 650-700°C at a rate of 5-10°C / min in a nitrogen atmosphere with an oxygen volume content of 0.08%-0.1%, and keeping warm for 30-60min; then heating to 1250-1300°C at a rate of 3-5°C / min in a nitrogen atmosphere with an oxygen volume content of 3%-5%, and sintering and keeping warm for 2-3h; after sintering, cooling to room temperature at a rate of 5-10°C / min in a nitrogen atmosphere with an oxygen volume content of 0.08%-0.1%, thereby obtaining a high permeability soft ferrite core.

10. The manufacturing method according to claim 9, characterized in that: In step (2), the pre-firing temperature is 700-850°C, the pre-firing heating rate is 3-5°C / min, and the pre-firing time is 1-2h.

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