A high-b-s manganese-zinc ferrite material resistant to large current and high temperature and a preparation method and application thereof

Abstract

This invention discloses a high-current, high-temperature, high-Bs manganese-zinc ferrite material, its preparation method, and its application, belonging to the field of manganese-zinc ferrite material preparation technology. The preparation steps of the high-current, high-temperature, high-Bs manganese-zinc ferrite material include: weighing Fe2O3, Mn3O4, and ZnO, mixing and ball milling with water to obtain slurry 1; pre-sintering slurry 1 to obtain ferrite powder; adding auxiliary components CaCO3, Nb2O5, V2O5, NiO, MoO3, and SiO2 to the ferrite powder, mixing and ball milling with water to obtain slurry 2; adding a binder to slurry 2, stirring evenly, and drying to prepare pre-pressed powder; pressing the pre-pressed powder into shape and sintering to obtain the high-current, high-temperature, high-Bs manganese-zinc ferrite material. The high-current, high-temperature, high-Bs manganese-zinc ferrite material prepared by this invention exhibits Bs≥540mT at 100℃, Bs≥510mT at 120℃, and Bs≥480mT at 140℃ under conditions of 1kHz and 1200A / m.

Description

Technical Field

[0001] This invention belongs to the field of manganese-zinc ferrite material preparation technology, specifically relating to a high-current, high-temperature, high-Bs manganese-zinc ferrite material, its preparation method, and its application. Background Technology

[0002] The harsh, high-temperature environment surrounding an automotive engine requires the power module to maintain good electromagnetic characteristics even at high temperatures. When the power module is running at full load, its operating equilibrium temperature is typically between 100 and 140°C. This is based on the relationship between the inductance (permeability μ) of the magnetic core and the magnetization B (e.g., Figure 1 As shown in the figure, when the saturation magnetic flux density Bs of the core material decreases significantly due to temperature rise, the current in the coil increases, leading to an increase in the excitation magnetic field. The core may then experience magnetic saturation, causing a significant drop in inductance and thus losing its ability to suppress the current in the coil. This further exacerbates the increase in current in the coil, reducing the core's anti-saturation capability and creating a vicious cycle. Furthermore, the application of high-temperature, high-Bs manganese-zinc soft magnetic ferrites is beneficial for the development of power modules towards smaller size and higher energy efficiency. According to the formula for core power transmission capability: (P in the formula) th —Core power transmission capability; f—Operating frequency; ΔB—Incremental magnetic flux density; A e - Core cross-sectional area). Core power transmission capability P th The cross-sectional area A of the magnetic core is directly proportional to the core material's ΔB, while under otherwise constant conditions, ΔB is positively correlated with Bs. Therefore, for transmitting the same amount of power, the higher Bs is, the larger the core cross-sectional area A will be. e The smaller the core, the smaller the power module can be, which effectively reduces the size of the magnetic core product, thus making the power module lighter, thinner, and smaller. At the same time, the lighter, thinner, and smaller power module greatly reduces the amount of insulating enameled wire used in the transformer coil.

[0003] Existing technology CN103613370A discloses a method for preparing a high-temperature, high-Bs, low-power manganese-zinc ferrite material, wherein the prepared high-temperature, high-Bs, low-power manganese-zinc ferrite material has a Bs value of 453 mT at 100℃; existing technology CN102219488A discloses a high-temperature, high-Bs, low-loss MnZn ferrite material and its manufacturing method, wherein the prepared high-temperature, high-Bs, low-loss MnZn ferrite material has a Bs value of approximately 540 mT at room temperature (25℃) and approximately 450 mT at 100℃; existing technology CN111689770A discloses a high-temperature, high-Bs, low-loss soft magnetic ferrite material and its preparation method, wherein the Bs value is 480 mT at 100℃. The high-temperature saturation magnetic flux density of the currently disclosed manganese-zinc ferrite materials still needs further enhancement. Summary of the Invention

[0004] The purpose of this invention is to provide a high-current, high-temperature, high-Bs manganese-zinc ferrite material, its preparation method, and its applications. On one hand, the saturation magnetic flux density is increased by adjusting the iron-zinc molar ratio in the manganese-zinc ferrite material. On the other hand, its saturation magnetic flux density is further increased by introducing trace auxiliary components (CaCO3, Nb2O5, V2O5, NiO, MoO3, and SiO2).

[0005] To achieve the above objectives, the present invention provides the following technical solution: One of the technical solutions of this invention is to provide a method for preparing a high-current, high-temperature, high-Bs manganese-zinc ferrite material, comprising the following steps: The raw materials were weighed with a molar ratio of Fe2O3: 67%–69%, Mn3O4: 20%–21%, and ZnO: 10%–13%, mixed with water, and ball-milled to obtain slurry 1. Slurry 1 was pre-sintered to obtain ferrite powder. Auxiliary components CaCO3, Nb2O5, V2O5, NiO, MoO3, and SiO2 were added to the ferrite powder, mixed with water, and ball-milled to obtain slurry 2. A binder was added to slurry 2, stirred evenly, and dried to prepare pre-pressed powder. The pre-pressed powder was pressed into a green body, and the green body was sintered to obtain the high-current, high-temperature, high-Bs manganese-zinc ferrite material.

[0006] Preferably, during the ball milling process of the slurry 1, the material-to-water mass ratio is 1:(1-1.1), and the average particle size of the powder in the slurry 1 is 0.9-1.1 μm after ball milling.

[0007] Preferably, the pre-sintering temperature is 920–950°C and the time is 4–5 hours.

[0008] Preferably, the concentration of the auxiliary components in the ferrite powder is 1500-2000ppm CaCO3, 200-400ppm Nb2O5, 100-300ppm V2O5, 2000-3000ppm NiO, 200-400ppm MoO3, and 50-100ppm SiO2.

[0009] Preferably, during the ball milling process of the slurry 2, the material-to-water mass ratio is 1:(1-1.1), and the average particle size of the powder in the slurry 2 is 1.0-1.2 μm after ball milling.

[0010] Preferably, the adhesive is a polyvinyl alcohol (PVA) solution.

[0011] More preferably, the concentration of the PVA solution is 8 wt%, and the amount of PVA solution added is 10% of the mass of the slurry 2.

[0012] Preferably, the average particle size of the pre-compressed powder is 20–50 μm.

[0013] Preferably, a lubricant is added to the pre-compressed powder during the compression molding process.

[0014] More preferably, the lubricant is zinc stearate, and the amount added is 2‰ of the mass of the pre-compressed powder.

[0015] Preferably, the density of the green body is 3 ± 0.05 g / cm³. 3 .

[0016] Preferably, the sintering is densification curve sintering, which specifically involves: heating from room temperature to 1050-1150℃ in air for 5-6 hours, holding at 1050-1150℃ for 12-14 hours with an oxygen content of 1-2 vol% during the holding period, and then cooling to room temperature in an equilibrium atmosphere at a cooling rate of 2-3℃ / min; the oxygen partial pressure P(O2) of the equilibrium atmosphere is calculated according to the formula: log(P(O2))=ab / T, where a takes a value of 4-7, b takes a value of 11000-13000, and T is the absolute temperature.

[0017] The densification curve sintering provided by the present invention can effectively improve the saturation magnetic flux density of high current, high temperature, high Bs manganese zinc ferrite materials.

[0018] In this invention, room temperature refers to a temperature of 10–30°C.

[0019] Generally speaking, the oxygen partial pressure (P) in the surrounding atmosphere O2 When appropriate, oxides and ferrites neither oxidize nor reduce, or in other words, the absorbed oxygen equals the released oxygen, reaching a state of chemical equilibrium. The oxygen partial pressure at this point is called the equilibrium oxygen partial pressure. The equilibrium atmosphere is a function of temperature. Because the oxygen density inside the ferrite sample is greater than that in the surrounding atmosphere, as the temperature rises, the oxygen decomposition pressure inside the ferrite sample increases faster than the oxygen partial pressure in the surrounding atmosphere. As a result, the ferrite sample releases oxygen, and vice versa. To ensure that the composition, ionic state, and microstructure of the ferrite meet the requirements, ferrite sintering must be carried out in an equilibrium atmosphere.

[0020] The second technical solution of the present invention provides a high-current, high-temperature, high-Bs manganese-zinc ferrite material prepared according to the above-mentioned preparation method of high-current, high-temperature, high-Bs manganese-zinc ferrite material.

[0021] The third technical solution of this invention provides an application of the above-mentioned high-current, high-temperature, high-Bs manganese-zinc ferrite material in the preparation of automotive electronics.

[0022] The beneficial technical effects of the present invention are as follows: The high-current, high-temperature, high-Bs manganese-zinc ferrite material prepared by this invention has Bs≥540mT at 100℃, Bs≥510mT at 120℃, and Bs≥480mT at 140℃ under conditions of 1kHz and 1200A / m. Automotive electronics prepared using this material can meet the application requirements of automotive electronics in high-temperature and high-current applications. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This represents the relationship between the permeability μ of the magnetic core and the magnetization B. Detailed Implementation

[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0026] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0027] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0028] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0029] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0030] This invention provides a method for preparing a high-current, high-temperature, high-Bs manganese-zinc ferrite material, comprising the following steps: The raw materials were weighed with a molar ratio of Fe2O3: 67%–69%, Mn3O4: 20%–21%, and ZnO: 10%–13%, mixed with water, and ball-milled to obtain slurry 1. Slurry 1 was pre-sintered to obtain ferrite powder. Auxiliary components CaCO3, Nb2O5, V2O5, NiO, MoO3, and SiO2 were added to the ferrite powder, mixed with water, and ball-milled to obtain slurry 2. A binder was added to slurry 2, stirred evenly, and dried to prepare pre-pressed powder. The pre-pressed powder was pressed into a green body, and the green body was sintered to obtain the high-current, high-temperature, high-Bs manganese-zinc ferrite material.

[0031] Furthermore, during the ball milling process of the slurry 1, the material-to-water mass ratio is 1:(1-1.1), and the average particle size of the powder in the slurry 1 is 0.9-1.1 μm after ball milling.

[0032] Furthermore, the pre-sintering temperature is 920–950°C, and the time is 4–5 hours.

[0033] Furthermore, the concentrations of the auxiliary components in the ferrite powder are: CaCO3 1500–2000 ppm, Nb2O5 200–400 ppm, V2O5 100–300 ppm, NiO 2000–3000 ppm, MoO3 200–400 ppm, and SiO2 50–100 ppm.

[0034] Furthermore, during the ball milling process of the slurry 2, the material-to-water mass ratio is 1:(1-1.1), and the average particle size of the powder in the slurry 1 is 1.0-1.2 μm after ball milling.

[0035] Furthermore, the adhesive is a PVA solution. Furthermore, the concentration of the PVA solution is 8 wt%, and the amount of PVA solution added is 10% of the mass of the slurry 2.

[0036] Furthermore, the average particle size of the pre-compressed powder is 20–50 μm.

[0037] Furthermore, a lubricant is added to the pre-compressed powder during the compression molding process.

[0038] Furthermore, the lubricant is zinc stearate, and the amount added is 2‰ of the mass of the pre-compressed powder.

[0039] Furthermore, the density of the green body is 3 ± 0.05 g / cm³. 3 .

[0040] Furthermore, the sintering is densification curve sintering, which specifically involves: heating from room temperature to 1050-1150℃ in air for 5-6 hours, holding at 1050-1150℃ for 12-14 hours with an oxygen content of 1-2 vol% during the holding period, and then cooling to room temperature in an equilibrium atmosphere at a cooling rate of 2-3℃ / min; the oxygen partial pressure P(O2) of the equilibrium atmosphere is calculated according to the formula: log(P(O2))=ab / T, where a takes a value of 4-7, b takes a value of 11000-13000, and T is the absolute temperature.

[0041] This invention also provides a high-current, high-temperature, high-Bs manganese-zinc ferrite material prepared according to the above-described method for preparing high-current, high-temperature, high-Bs manganese-zinc ferrite material; and the application of the high-current, high-temperature, high-Bs manganese-zinc ferrite material in the preparation of automotive electronics.

[0042] Example 1 1) Weigh the raw materials according to the formula Fe2O3: 67.5mol%, Mn3O4: 21mol%, ZnO: 11.5mol%, mix them, and then ball mill them to obtain slurry 1; wherein, the mass ratio of ball milling material to water is 1:1, the mass ratio of material to ball is 1:3 (the balls are steel balls with ф=3mm), the ball milling time is 30min, and the average particle size of the powder in slurry 1 is 1.1μm.

[0043] 2) The slurry 1 obtained in step 1) is pre-fired in a natural gas rotary kiln at 950°C for 4 hours under air conditions to obtain ferrite powder with a spinel synthesis degree of 30% to 50%.

[0044] 3) The ferrite powder obtained in step 2) is mixed with auxiliary components. The concentrations of the auxiliary components in the ferrite powder are CaCO3 1800ppm, Nb2O5 400ppm, V2O5 100ppm, NiO 2500ppm, MoO 3300ppm, and SiO 250ppm. The mixture is then ball-milled to obtain slurry 2. The mass ratio of the ball-milling material to water is 1:1, and the mass ratio of the material to the ball is 1:4 (the balls are steel balls with a diameter of φ=3mm). The ball-milling time is 100 min, and the average particle size of the powder in slurry 2 is 1.1 μm. 10% (by weight) of PVA solution (concentration 8wt%) is added to slurry 2, and the mixture is stirred for 15 min. The mixture is then spray-dried to obtain pre-compressed powder with an average particle size of 32 μm.

[0045] 4) Add zinc stearate to the pre-compressed powder obtained in step 3), the amount of which is 2wt‰ of the pre-compressed powder, and press it into shape. The density of the green body is controlled to be 3g / cm³. 3 .

[0046] 5) Perform curve sintering on the green body obtained in step 4): Heating stage: 25℃~1150℃, heating in air for 6 hours; Holding stage: 1150℃, oxygen content 1.2 vol% (the remainder is nitrogen), holding for 14 hours; Cooling stage: 1150℃~25℃, cooling in a balanced atmosphere (oxygen content 1.2 vol%, the remainder is nitrogen) at a rate of 2.5℃ / min. Obtain a high-current, high-temperature, high-Bs manganese-zinc ferrite material.

[0047] Examples 2-5 The difference from Example 1 is the amount of raw materials used, as shown in Table 1.

[0048] The performance of the high-current, high-temperature, high-Bs manganese-zinc ferrite materials prepared in Examples 1-5 was measured. The test items and results are shown in Table 1.

[0049] Table 1. Performance of the high-current, high-temperature, high-Bs manganese-zinc ferrite materials prepared in Examples 1-5 The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a high-current, high-temperature, high-Bs manganese-zinc ferrite material, characterized in that, Includes the following steps: The raw materials were weighed with a molar ratio of Fe2O3: 67%–69%, Mn3O4: 20%–21%, and ZnO: 10%–13%, mixed with water, and ball-milled to obtain slurry 1. Slurry 1 was pre-sintered to obtain ferrite powder. Auxiliary components CaCO3, Nb2O5, V2O5, NiO, MoO3, and SiO2 were added to the ferrite powder, mixed with water, and ball-milled to obtain slurry 2. A binder was added to slurry 2, stirred evenly, and then dried to prepare pre-pressed powder. The pre-compressed powder is pressed into a green body, and the green body is sintered to obtain the high-current, high-temperature, high-Bs manganese-zinc ferrite material.

2. The preparation method of the high-current, high-temperature, high-Bs manganese-zinc ferrite material according to claim 1, characterized in that, During the ball milling process of the slurry 1, the material-to-water mass ratio is 1:(1-1.1), and the average particle size of the powder in the slurry 1 is 0.9-1.1 μm after ball milling.

3. The preparation method of the high-current, high-temperature, high-Bs manganese-zinc ferrite material according to claim 1, characterized in that, The pre-sintering temperature is 920–950°C, and the time is 4–5 hours.

4. The preparation method of the high-current, high-temperature, high-Bs manganese-zinc ferrite material according to claim 1, characterized in that, The concentrations of the auxiliary components in the ferrite powder are: CaCO3 1500–2000 ppm, Nb2O5 200–400 ppm, V2O5 100–300 ppm, NiO 2000–3000 ppm, MoO3 200–400 ppm, and SiO2 50–100 ppm.

5. The preparation method of the high-current, high-temperature, high-Bs manganese-zinc ferrite material according to claim 1, characterized in that, During the ball milling process of the slurry 2, the material-to-water mass ratio is 1:(1-1.1), and the average particle size of the powder in the slurry 2 is 1.0-1.2 μm after ball milling.

6. The preparation method of the high-current, high-temperature, high-Bs manganese-zinc ferrite material according to claim 1, characterized in that, The adhesive is a polyvinyl alcohol solution.

7. The preparation method of the high-current, high-temperature, high-Bs manganese-zinc ferrite material according to claim 1, characterized in that, The average particle size of the pre-compressed powder is 20–50 μm; and / or the density of the green body is 3 ± 0.05 g / cm³. 3 .

8. The preparation method of the high-current, high-temperature, high-Bs manganese-zinc ferrite material according to claim 1, characterized in that, The sintering is densification curve sintering, which specifically involves: heating from room temperature to 1050-1150℃ in air for 5-6 hours, holding at 1050-1150℃ for 12-14 hours with an oxygen content of 1-2 vol% during the holding period, and then cooling to room temperature in an equilibrium atmosphere at a cooling rate of 2-3℃ / min; the oxygen partial pressure P(O2) in the equilibrium atmosphere is calculated according to the formula: log(P(O2))=ab / T, where a takes a value of 4-7, b takes a value of 11000-13000, and T is the absolute temperature.

9. A high-current, high-temperature, high-Bs manganese-zinc ferrite material prepared by the preparation method of the high-current, high-temperature, high-Bs manganese-zinc ferrite material according to any one of claims 1 to 8.

10. The application of the high-current, high-temperature, high-Bs manganese-zinc ferrite material according to claim 9 in the preparation of automotive electronics.

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