A composite ferrite material, a method for preparing the same and applications thereof

Abstract

The application relates to a composite ferrite material and a preparation method and application thereof, which comprises the following steps: weighing MnZn ferrite main material according to the mole percentage and in the form of oxides; weighing a first additive according to the weight percentage and in the form of oxides; weighing a second additive according to the weight percentage; pre-sintering the MnZn ferrite main material after grinding in a ball mill; drying the obtained ball material after the first ball grinding; second ball grinding after adding the first additive and the second additive; adding an organic binder to the powder material after the second ball grinding, uniformly mixing, granulating, pressing into a green body, sintering the green body, and obtaining the composite ferrite material. The electromagnetic performance of the material itself is improved, the DC superposition resistance of the material itself is improved, and the magnetic permeability of the magnetic core can remain unchanged under a certain DC magnetic field.

Description

Technical Field

[0001] This invention relates to the field of electronic materials technology, and in particular to a composite ferrite material, its preparation method, and its application. Background Technology

[0002] Ferrite is an important fundamental material for electronic devices. Magnetic cores made from soft magnetic materials are mainly used in the manufacture of electronic transformers, inductors, and filters. MnZn ferrite materials, due to their high saturation magnetic flux density (Bs), high initial permeability (μi), and low loss (PL), are widely used in switching power supply transformers. High-efficiency power supply devices, such as AC-DC and DC-DC converters, and switching power supplies, are fundamental electronic components in the modern electronics and information industry. Transformer cores made of MnZn ferrite are crucial for power transmission and conversion in power supply devices, and also significantly contribute to the size, weight, and losses of these devices. In some applications, such as chokes, horizontal output converters, and flyback transformers, in addition to requiring miniaturization and high performance of the inductor core, high stability and reliability under applied bias current are also essential. In particular, a higher saturation current carrying capacity (generally based on the maximum current that can be carried when the inductance drops to 70%) is desirable.

[0003] However, under DC superposition conditions, the magnetic core does not operate with the origin of the hysteresis loop as its working center, but rather undergoes AC magnetization deviating from a magnetically neutral state. Compared to magnetization under a simple AC signal, the core's permeability decreases and losses increase dramatically, leading to a decline in the efficiency and stability of the power supply device. In severe cases, this can cause excessive heat generation or even burnout. One possible solution to address the DC superposition characteristics of the magnetic core is to create an air gap in the core. This prevents the core from rapidly entering a saturation magnetization state under DC bias, mitigating the influence of the DC magnetic field on the permeability and improving the core's resistance to DC superposition to some extent. However, creating an air gap reduces the core's inductance and introduces leakage inductance at the gap. Due to this leakage inductance, a back electromotive force is generated when the switching device is turned off, potentially causing overvoltage breakdown. Furthermore, the leakage inductance can form an oscillating circuit with the distributed capacitance in the circuit and the distributed capacitance of the transformer coil, causing the circuit to oscillate and radiate electromagnetic energy, resulting in electromagnetic interference.

[0004] Therefore, it is necessary to develop a magnetic composite ferrite material with resistance to DC superposition. Summary of the Invention

[0005] The purpose of this invention is to provide a composite ferrite material, its preparation method, and its application, in order to solve the problem of leakage inductance, which easily causes overvoltage breakdown of switching devices, resulting in circuit oscillation and outward radiation of electromagnetic energy, causing electromagnetic interference.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing a composite ferrite material, comprising the following steps:

[0008] Based on molar percentage and calculated as oxides, 53.1~55.1 mol% Fe2O3, 34.9~36.9 mol% MnO, and 8~12 mol% ZnO were weighed and mixed to obtain the MnZn ferrite main material;

[0009] Based on weight percentages and calculated as oxides, 0.10~0.50wt% Co2O3, 0.05wt% ZrO2, 0.03wt% V2O5, and 0.15wt% CaO were weighed and mixed to obtain the first additive; 0.1~0.5wt% YIG ferrite nanoparticles were weighed and used as the second additive.

[0010] After placing the MnZn ferrite main material into the ball mill, the grinding material is pre-fired, and the ball milling material obtained after one ball milling is dried.

[0011] After adding the first additive and the second additive, the material is ball-milled twice. An organic binder is added to the powder after the second ball milling and mixed evenly. The powder is then granulated and pressed into a green embryo. The green embryo is then sintered to obtain a composite ferrite material.

[0012] Furthermore, the YIG ferrite nanoparticles are Y3Fe5O 12 or Y3Fe 5-x Al x O 12 Its component is Y3Fe5O 12 The particle size is less than 100 nm; the composition is Y3Fe 5-x Al x O 12 The particles were prepared by the sol-gel method as follows: Fe(NO3)3 and Y(NO3)3 were dissolved in distilled water and stirred to obtain solution 1, while Al(NO3)3 and citric acid were dissolved and stirred to obtain solution 2; then solution 1 was added dropwise to solution 2 and stirred continuously, and the pH value of the solution was adjusted to 6-7 using ammonia water; ethylene glycol was added dropwise to the mixed solution and heated and stirred until the water evaporated to obtain gel; the temperature was further increased to allow the gel to spontaneously combust into powder, and the powder was sintered at 870~920 ℃ for 4 h to obtain powder with a particle size of less than 100 nm.

[0013] Furthermore, in the first ball milling, deionized water of equal weight to the MnZn ferrite main material is added, and the ball milling is carried out for more than 1.5 hours; the second ball milling includes a second ball milling for 3.5 hours after the addition of the first additive and the second additive.

[0014] Furthermore, the pre-firing conditions include pre-firing in an air atmosphere at 890℃~920℃, followed by holding at that temperature for 0.5h~2h.

[0015] Further, the molding process includes: drying the slurry after secondary ball milling, adding 12wt% PVA adhesive, granulating by hand kneading, and then pressing it into shape in a mold under 70MPa conditions.

[0016] Furthermore, the holding time during the molding process is 20-25 seconds, and the molding process includes pressing a ring-shaped green preform, the size of which is 18mm*8mm*3mm.

[0017] Furthermore, the sintering process is segmented sintering: the green blank is placed in a tube furnace for sintering, and the temperature is slowly increased in the range of 50℃ to 500℃ at a rate of 1.5℃ / min, with air introduced; in the range of 500℃ to 850℃, the temperature is increased at a rate of 2.5℃ / min, with air introduced; in the range of 850℃ to 1220℃, the temperature is increased at a rate of 2℃ / min; after the temperature reaches 1220℃, it is held for 4 to 8 hours with an oxygen partial pressure of 1.5% to 3.3%; and sintering in a balanced atmosphere is carried out in the cooling section.

[0018] Furthermore, within the temperature rise range of 850℃ to 1220℃, nitrogen gas is introduced starting 15 minutes before the temperature reaches 1220℃.

[0019] Secondly, the present invention provides a composite ferrite material, which is prepared by a method for preparing composite ferrite materials.

[0020] Thirdly, the present invention provides an application of a composite ferrite material, which is used in electronic components.

[0021] Compared with the prior art, the present invention has the following technical effects:

[0022] This application provides a composite ferrite in which Co ions can modulate the magnetocrystalline anisotropy of MnZn ferrite, thereby adjusting the trend of its permeability change with a DC magnetic field. To control the deterioration of other electromagnetic properties of MnZn ferrite caused by excessive Co doping, such as decreased permeability, reduced resistivity, and increased magnetic loss, a YIG ferrite phase is introduced. Since YIG particles are a magnetic phase, when distributed between the grains of MnZn ferrite, they can promote long-range magnetic interactions, effectively preventing a decrease in permeability. This allows the material to maintain high permeability under DC superposition conditions, exhibiting excellent DC superposition resistance.

[0023] This application also provides a method for preparing composite ferrites. Based on a suitable main formulation, the method utilizes composite doping with various additives such as CaO, ZrO2, Co2O3, V2O5, and nano-YIG ferrites to control the microstructure and electromagnetic properties of the material. Specifically, the doping of high-resistivity oxides such as CaO and ZrO2 is beneficial for improving the resistivity of the material; the doping of V2O5 is beneficial for forming liquid-phase sintering, effectively promoting the solid-phase reaction during sintering and improving grain uniformity; the doping of Co2+ utilizes the positive magnetocrystalline anisotropy of Co2+ to control the overall magnetocrystalline anisotropy of MnZn ferrites; and the doping of YIG ferrite nanoparticles can enhance the long-range magnetic interaction between grains and effectively prevent the decrease in magnetic permeability. Ultimately, the MnZn power ferrite prepared through the composite addition of various additives and a specific sintering process exhibits uniform grain size distribution, high permeability, and excellent resistance to DC superposition. Its initial permeability is 1530 A, only beginning to decrease when the DC magnetic field reaches 223 A / m, and retaining 70% of its initial value at 277 A / m. By improving the material's inherent electromagnetic properties and enhancing its resistance to DC superposition, the permeability of the core can remain constant under a given DC magnetic field.

[0024] This application further provides the application of composite ferrites in the fabrication of electronic materials. Based on this application, the composite ferrite utilizes Co doping to adjust DC superposition characteristics by introducing a YIG garnet phase. Since YIG nanoparticles are a magnetic phase, they possess high resistance to DC superposition while maintaining magnetic permeability. Therefore, applying this composite ferrite to electronic materials enhances the DC superposition resistance of the MnZn ferrite material itself. When the magnetic core itself has strong DC superposition resistance, the magnetic core does not require an air gap. In this case, the magnetic core has a complete circuit, avoiding the influence of leakage inductance caused by the air gap, thus showing great application potential in the fabrication of electronic devices.

[0025] This invention prepares composite ferrites via an oxide ceramic method. By adding a first additive and a second additive after a single ball milling process, followed by a second ball milling, the composite ferrite achieves a uniform composition.

[0026] YIG ferrite particles have a particle size of less than 100 nm, which is much smaller than the grain size of MnZn ferrite. They can be uniformly distributed at the grain boundaries of MnZn ferrite, enhancing the long-range magnetic interaction between grains. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the preparation method of composite ferrite provided in the embodiments of this application;

[0029] Figure 2 This is a graph showing the change of magnetic permeability with DC magnetic field provided in Embodiment 1 of this application;

[0030] Figure 3 This is a graph showing the change of magnetic permeability with DC magnetic field provided in Embodiment 2 of this application;

[0031] Figure 4 This is a graph showing the change of magnetic permeability with DC magnetic field provided in Embodiment 3 of this application;

[0032] Figure 5 This is a graph showing the change of magnetic permeability with DC magnetic field provided in Embodiment 4 of this application;

[0033] Figure 6 This is a graph showing the change of magnetic permeability with DC magnetic field provided in Embodiment 5 of this application;

[0034] Figure 7 This is a graph showing the change of magnetic permeability with DC magnetic field provided in Embodiment 6 of this application;

[0035] Figure 8 This is a graph showing the change of magnetic permeability with DC magnetic field provided in Comparative Example 1 of this application;

[0036] Figure 9 This is a graph showing the change of magnetic permeability with DC magnetic field provided in Comparative Example 2 of this application;

[0037] Figure 10 This is a graph showing the change of magnetic permeability with DC magnetic field provided in Embodiment 7 of this application;

[0038] Figure 11 This is a graph showing the change of magnetic permeability with DC magnetic field provided in Embodiment 8 of this application;

[0039] Figure 12 This is a graph showing the change of magnetic permeability with DC magnetic field provided in Embodiment 9 of this application;

[0040] Figure 13 This is a graph showing the change of magnetic permeability with a DC magnetic field, provided in Comparative Example 3 of this application. Detailed Implementation

[0041] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0042] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0043] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items.

[0044] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0045] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0046] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a well-known unit of mass in the chemical industry, such as µg, mg, g, or kg.

[0047] The terms “first” and “second” are used only to describe the purpose and to distinguish between purposes such as substances, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0048] Soft magnetic ferrites, as the name suggests, are magnetic materials characterized by their magnetic conductivity. Just as metals conduct electricity, some materials are magnetic; these are called magnetic materials. Magnetic materials are divided into hard magnetic and soft magnetic materials. Hard magnetic materials are permanent magnets, meaning they possess magnetism without the need for an external current-carrying solenoid, and their magnetism does not disappear. Soft magnetic materials, on the other hand, are not inherently magnetic; they only generate a magnetic field when an external current-carrying solenoid is applied, and this magnetic field disappears when the applied current is removed.

[0049] Ferrites are "functional ceramic materials" made by sintering a mixture of iron oxides and other metal oxides. They possess good magnetic permeability and, compared to ordinary metals, have advantages such as weaker coercivity and lower remanence after the removal of external current. Generally, based on their formulation, they are classified into four types: manganese-zinc ferrites, nickel-zinc ferrites, barium-zinc ferrites, and magnesium-zinc ferrites.

[0050] This application provides a composite ferrite material to better adjust the magnetocrystalline anisotropy of the composite ferrite material and thus improve its DC resistance. The composite ferrite material of this application improves the magnetocrystalline anisotropy of the composite ferrite material through cobalt doping. Simultaneously, to overcome the decrease in permeability and deterioration of electromagnetic performance caused by large-scale cobalt doping, the DC resistance is improved by compositing MnZn ferrite with YIG ferrite particles, thereby ensuring permeability.

[0051] This application provides a composite ferrite material, comprising:

[0052] The main material is MnZn ferrite, which, by molar percentage and calculated as oxides, comprises 53.1~55.1 mol% Fe2O3, 34.9~36.9 mol% MnO, and 8~12 mol% ZnO; the first additive, by weight percentage and calculated as oxides, comprises 0.10~0.50 wt% Co2O3, 0.05 wt% ZrO2, 0.03 wt% V2O5, and 0.15 wt% CaO; the second additive is YIG ferrite particles, which, by weight percentage, comprises 0.1~0.5 wt% YIG ferrite particles.

[0053] In one possible embodiment, the YIG ferrite particles are nanoscale, with a particle size <100 nm.

[0054] In one possible embodiment, the YIG ferrite particles are mainly composed of Y3Fe5O. 12 .

[0055] In another aspect, this application provides a method for preparing a composite ferrite material, such as... Figure 1 As shown, the preparation method includes the following steps:

[0056] S01: Prepare the MnZn ferrite main material, calculated by molar percentage as oxides, including 53.1~55.1 mol% Fe2O3, 34.9~36.9 mol% MnO4, and 8~12 mol% ZnO, weighed after calculation; additives, calculated by weight percentage as oxides, include 0.10~0.50 wt% Co2O3, 0.05 wt% ZrO2, 0.03 wt% V2O5, and 0.15 wt% CaO; provide dopant YIG ferrite particles, including 0.1~0.5 wt% nano YIG particles by weight; one-time ball milling, placing the MnZn ferrite main material into the ball mill as abrasive;

[0057] S02: Dry the ball milling material obtained after the first ball milling; add the first additive and the second additive and then ball mill a second time;

[0058] S03: PVA organic binder is added to the powder after secondary ball milling and mixed evenly. After granulation, it is pressed into a green embryo and sintered under controlled temperature and oxygen partial pressure conditions.

[0059] S04: Using a DC power supply of model PLR36-20 and model IWATSU SY-8232 BH An analyzer was used to test the DC-resistant superimposed MnZn ferrite magnetic ring prepared in this application. Three sets of coils, each with five turns, were wound around the magnetic ring. One set of coils was connected to a DC power supply to provide a DC magnetic field along the magnetic circuit of the magnetic ring. The magnetic field strength could be determined according to... H=NI / l e ,in N The number of coil turns. I For current, l e This is the effective length of the magnetic ring. The remaining two sets of coils are connected... BH The analyzer was used to test the permeability under the following conditions: 1 kHz, 1 A / m, 25 o C.

[0060] The following description is based on specific embodiments.

[0061] Example

[0062]

[0063] Comparative Example

[0064]

[0065] Example

[0066]

[0067] Comparative Example

[0068]

[0069] Example 1

[0070] A composite ferrite, prepared by the following steps:

[0071] (1) The main MnZn ferrite material is prepared by weight percentage and calculated as oxides, including 53.1 mol% Fe2O3, 34.9 mol% Mn3O4, and 12 mol% ZnO. The first additive is calculated by weight percentage and calculated as oxides, including 0.10 wt% Co2O3, 0.05 wt% ZrO2, 0.03 wt% V2O5, and 0.15 wt% CaO. The second additive is Y3Fe5O 12 Ferrite particles, provided by weight percentage, consist of 0.1 wt% nano-YIG particles.

[0072] (2) Place the MnZn ferrite main material into a ball mill, add an equal mass of deionized water, and grind the material once. After drying the ball mill material obtained after the first ball milling, add the first additive and the second additive and then ball mill a second time. Add organic binder PVA glue to the powder after the second ball milling and mix evenly. After granulation, press it into a green embryo. Sinter the material by controlling the temperature and oxygen partial pressure to obtain the composite ferrite material.

[0073] Testing of composite ferrite materials:

[0074] Take the composite ferrite magnetic ring obtained in the above steps, and use a DC power supply of model PLR36-20 and model IWATSU SY-8232... BH The analyzer is used for testing. Three sets of coils, each with five turns, are wound around the magnetic ring. One set of coils is connected to a DC power supply to provide a DC magnetic field along the magnetic circuit of the magnetic ring. The magnetic field strength can be determined according to... H=NI / l e ,in N The number of coil turns. I For current, l e This represents the effective length of the magnetic ring. Repeat the test multiple times. Figure 2 The diagram shows the variation of the magnetic permeability of the composite ferrite material obtained in Example 1 with a DC magnetic field. The horizontal axis represents... H dc (A / m), with the vertical axis representing permeability. H μmax This represents the DC magnetic field corresponding to the point where the permeability reaches its maximum value. H μ100 This represents the DC magnetic field corresponding to the point where the permeability decreases to 100% of the initial permeability.H μ70 This represents the DC magnetic field corresponding to a decrease in permeability to 70% of the initial permeability. Figure 2 It can be seen that the permeability first increases and then decreases with the increase of the DC magnetic field. The initial permeability of the magnetic ring is 1686. H μmax It is 49A / m. H μ100 It is 95 A / m. H μ70 It is 135A / m.

[0075] Compared with Comparative Example 1, this demonstrates that the DC stacking resistance of MnZn ferrite was improved by incorporating 0.10 wt% Co2O3 and 0.1 wt% nano-YIG particles.

[0076] Example 2

[0077] A composite ferrite, prepared by the following steps:

[0078] (1) The main MnZn ferrite material is prepared by weight percentage and calculated as oxides, including 53.6 mol% Fe2O3, 34.9 mol% MnO, and 11.5 mol% ZnO. The first additive is calculated by weight percentage and calculated as oxides, including 0.20 wt% Co2O3, 0.05 wt% ZrO2, 0.03 wt% V2O5, and 0.15 wt% CaO. The second additive is Y3Fe5O 12 Ferrite particles, provided by weight percentage: 0.2 wt% nano-YIG particles.

[0079] (2) Place the MnZn ferrite main material into a ball mill, add an equal mass of deionized water, and grind the material once. After drying the ball mill material obtained after the first ball milling, add the first additive and the second additive and then ball mill a second time. Add organic binder PVA glue to the powder after the second ball milling and mix evenly. After granulation, press it into a green embryo. Sinter the material by controlling the temperature and oxygen partial pressure to obtain the composite ferrite material.

[0080] Figure 3 The figure shows the change in permeability of the magnetic ring obtained in Example 2 as a function of a DC magnetic field. The initial permeability of this magnetic ring is 1576. H μmax It is 79A / m. H μ100 It is 147 A / m. H μ70 It is 192 A / m.

[0081] Compared with Example 1, this demonstrates that simultaneously increasing the amount of Co2O3 and nano-YIG particles can further improve the DC superposition resistance of MnZn ferrite.

[0082] Example 3

[0083] A composite ferrite, prepared by the following steps:

[0084] (1) Prepare the MnZn ferrite main material, calculated by molar percentage as oxides, including 54.1 mol% Fe2O3, 35.4 mol% MnO, and 10.5 mol% ZnO, and weigh them; the first additive, calculated by weight percentage as oxides, includes 0.30 wt% Co2O3, 0.05 wt% ZrO2, 0.03 wt% V2O5, and 0.15 wt% CaO; the second additive is Y3Fe5O 12 Ferrite particles, by weight percentage, include 0.1 wt% nano-YIG particles.

[0085] (2) Place the MnZn ferrite main material into a ball mill, add an equal mass of deionized water, and grind the material once. After drying the ball mill material obtained after the first ball milling, add the first additive and the second additive and then ball mill a second time. Add organic binder to the powder after the second ball milling and mix evenly. After granulation, press it into a green embryo. Sinter the material by controlling the temperature and oxygen partial pressure to obtain the composite ferrite material.

[0086] Figure 4 The figure shows the variation of the magnetic permeability of the magnetic ring in Example 3 with a DC magnetic field. The initial magnetic permeability of this magnetic ring is 1421. H μmax It is 142 A / m. H μ100 It is 221 A / m. H μ70 The value was 283 A / m. Compared with Example 1, it is shown that with the same amount of nano-YIG particles added, increasing the Co2O3 content improves the DC superposition resistance of MnZn ferrite, but the initial permeability decreases from 1668 to 1421.

[0087] Example 4

[0088] A composite ferrite, prepared by the following steps:

[0089] (1) Prepare the MnZn ferrite main material, calculated by molar percentage as oxides, including 54.1 mol% Fe2O3, 35.9 mol% MnO, and 10 mol% ZnO, and weigh them; the first additive, calculated by weight percentage as oxides, includes 0.30 wt% Co2O3, 0.05 wt% ZrO2, 0.03 wt% V2O5, and 0.15 wt% CaO; the second additive is Y3Fe5O 12 Ferrite particles, by weight percentage, include 0.3 wt% nano-YIG particles.

[0090] (2) Place the MnZn ferrite main material into a ball mill, add an equal mass of deionized water, and grind the material once. After drying the ball mill material obtained after the first ball milling, add the first additive and the second additive and then ball mill a second time. Add organic binder to the powder after the second ball milling and mix evenly. After granulation, press it into a green embryo. Sinter the material by controlling the temperature and oxygen partial pressure to obtain the composite ferrite material.

[0091] Figure 5 The figure shows the variation of the magnetic permeability of the magnetic ring in Example 4 with a DC magnetic field. The initial magnetic permeability of this magnetic ring is 1530. H μmax It is 145A / m. H μ100 It is 223 A / m. H μ70 It is 277 A / m.

[0092] Compared to Example 2, it is shown that further increasing the amount of Co2O3 and nano-YIG particles improves the DC superposition resistance of MnZn ferrite, while the initial permeability only decreases slightly by 46. Compared to Example 3, it is shown that with the same Co2O3 content, increasing the amount of nano-YIG particles can improve the initial permeability while maintaining the DC superposition resistance.

[0093] Example 5

[0094] A composite ferrite, prepared by the following steps:

[0095] (1) Prepare the main material of MnZn ferrite, which, according to the molar percentage, is calculated as oxides and includes 54.1 mol% Fe2O3, 36.9 mol% MnO, and 9 mol% ZnO, and weighed after calculation; the first additive, according to the weight percentage, is calculated as oxides and includes 0.40 wt% Co2O3, 0.05 wt% ZrO2, 0.03 wt% V2O5, and 0.15 wt% CaO; and provide the second additive YIG ferrite particles, which, according to the weight percentage, include 0.4 wt% nano YIG particles.

[0096] (2) Place the MnZn ferrite main material into a ball mill, add an equal mass of deionized water, and grind the material once. After drying the ball mill material obtained after the first ball milling, add the first additive and the second additive and then ball mill a second time. Add organic binder to the powder after the second ball milling and mix evenly. After granulation, press it into a green embryo. Sinter the material by controlling the temperature and oxygen partial pressure to obtain the composite ferrite material.

[0097] Figure 6 The figure shows the variation of the magnetic permeability of the magnetic ring in Example 5 with a DC magnetic field. The initial magnetic permeability of this magnetic ring is 1251. H μmax It is 111 A / m. H μ100 It is 200 A / m. H μ70 It is 301A / m.

[0098] Compared with Example 4, it is shown that further increasing the amount of Co2O3 and nano YIG particles does not significantly improve its resistance to DC superposition; instead, the initial permeability decreases to 1251.

[0099] Example 6

[0100] A composite ferrite, prepared by the following steps:

[0101] (1) Prepare the MnZn ferrite main material, which, according to molar percentage and calculated as oxides, includes 55.1 mol% Fe2O3, 36.9 mol% MnO, and 8 mol% ZnO, and weighed accordingly; the first additive, according to weight percentage and calculated as oxides, includes 0.50 wt% Co2O3, 0.05 wt% ZrO2, 0.03 wt% V2O5, and 0.15 wt% CaO; and provide the second additive Y3Fe5O. 12 Ferrite particles, by weight percentage, include 0.5 wt% nano-YIG particles.

[0102] (2) Place the MnZn ferrite main material into a ball mill, add an equal mass of deionized water, and grind the material once. After drying the ball mill material obtained after the first ball milling, add the first additive and the second additive and then ball mill a second time. Add organic binder to the powder after the second ball milling and mix evenly. After granulation, press it into a green embryo. Sinter the material by controlling the temperature and oxygen partial pressure to obtain the composite ferrite material.

[0103] Figure 7 The figure shows the variation of the magnetic permeability of the magnetic ring in Example 6 with a DC magnetic field. The initial magnetic permeability of this magnetic ring is 864. H μmax It is 126 A / m. H μ100It is 223 A / m. H μ70 It is 370A / m.

[0104] Compared with Example 5, it is shown that further increasing the amount of Co2O3 and nano YIG particles slightly improves the DC superposition resistance, but the initial permeability has decreased to 864.

[0105] Comparative Example 1

[0106] A composite ferrite, prepared by the following steps:

[0107] (1) MnZn ferrite main material was prepared and weighed according to the molar percentage of oxides, including 54.1 mol% Fe2O3, 35.9 mol% MnO, and 10 mol% ZnO; the first additive was calculated according to the weight percentage of oxides, including 0.05 wt% ZrO2, 0.03 wt% V2O5, and 0.15 wt% CaO; no Co2O3 or YIG ferrite nanoparticles were added.

[0108] (2) Place the MnZn ferrite main material into a ball mill, add an equal mass of deionized water, and grind the material once. After drying the ball mill material obtained after the first ball milling, add the first additive and the second additive and then ball mill a second time. Add organic binder to the powder after the second ball milling and mix evenly. After granulation, press it into a green embryo. Sinter the material by controlling the temperature and oxygen partial pressure to obtain the composite ferrite material.

[0109] Figure 8 The figure shows the variation of the magnetic permeability of the magnetic ring in Comparative Example 1 with a DC magnetic field. The magnetic ring's... H μmax It is 18A / m. H μ100 Only 43 A / m, H μ70 It is only 89A / m.

[0110] Compared with Examples 1-5, in the absence of the addition of Co2O3 and nano YIG particles, although the initial permeability is very high, reaching 1775, its resistance to DC superposition is very poor, and the permeability decreases sharply with the DC magnetic field.

[0111] Comparative Example 2

[0112] A composite ferrite, prepared by the following steps:

[0113] (1) Prepare MnZn ferrite main material, which, according to molar percentage and calculated as oxides, includes 54.1 mol% Fe2O3, 36.9 mol% MnO, and 9 mol% ZnO, and weighed after calculation; the first additive, according to weight percentage and calculated as oxides, includes 0.60 wt% Co2O3, 0.05 wt% ZrO2, 0.03 wt% V2O5, and 0.15 wt% CaO; provide dopant YIG ferrite particles, which, according to weight percentage, include 0.6 wt% nano YIG particles.

[0114] (2) Place the MnZn ferrite main material into a ball mill, add an equal mass of deionized water, and grind the material once. After drying the ball mill material obtained after the first ball milling, add the first additive and the second additive and then ball mill a second time. Add organic binder to the powder after the second ball milling and mix evenly. After granulation, press it into a green embryo. Sinter the material by controlling the temperature and oxygen partial pressure to obtain the composite ferrite material.

[0115] Figure 9 The figure shows the variation of the magnetic permeability of the magnetic ring in Comparative Example 2 with a DC magnetic field. The magnetic ring's... H μmax It is 129 A / m. H μ100 It is 231 A / m. H μ70 It is 285A / m.

[0116] Compared with Examples 1-5, further increasing the amount of Co2O3 did not improve the DC superposition resistance of MnZn ferrite. Instead, the initial permeability dropped sharply to 556. Even with the addition of a large amount of nano YIG particles, the downward trend in initial permeability was not improved.

[0117] Example 7

[0118] A composite ferrite, prepared by the following steps:

[0119] (1) Prepare the MnZn ferrite main material, which, according to molar percentage and calculated as oxides, includes 54.1 mol% Fe2O3, 35.4 mol% MnO, and 10.5 mol% ZnO, and weigh it after calculation; the first additive, according to weight percentage and calculated as oxides, includes 0.30 wt% Co2O3, 0.05 wt% ZrO2, 0.03 wt% V2O5, and 0.15 wt% CaO; and provide the second additive Y3Fe 5- x Al x O 12 Ferrite particles, by weight percentage, contain 0.3 wt%, with an Al substitution amount of [missing information]. xIt is 0.16.

[0120] (2) Place the MnZn ferrite main material into a ball mill, add an equal mass of deionized water, and grind the material once. After drying the ball mill material obtained after the first ball milling, add the first additive and the second additive and then ball mill a second time. Add organic binder to the powder after the second ball milling and mix evenly. After granulation, press it into a green embryo. Sinter the material by controlling the temperature and oxygen partial pressure to obtain the composite ferrite material.

[0121] Figure 10 The figure shows the variation of the magnetic permeability of the magnetic ring in Example 7 with a DC magnetic field. The initial magnetic permeability of this magnetic ring is 1549. H μmax It is 142 A / m. H μ100 It is 218 A / m. H μ70 The value was 286 A / m. As shown in Examples 1-6, although the addition of YIG nanoparticles improved the DC superposition resistance, the saturation magnetic induction of the MnZn ferrite decreased sharply after compositing because the saturation magnetic induction of YIG is much smaller than that of MnZn ferrite. In this example, YIG ferrite nanoparticles with an Al substitution of 0.16 were used for compositing, which improved the saturation magnetic induction of the YIG ferrite nanoparticles. Therefore, while maintaining the excellent DC superposition resistance of the composite ferrite, the decrease in the saturation magnetic induction of the composite ferrite was effectively suppressed. Compared with Example 4, the saturation magnetic induction of this sample increased from 490 mT to 494 mT.

[0122] Example 8

[0123] A composite ferrite, prepared by the following steps:

[0124] (1) Prepare the MnZn ferrite main material, which, according to molar percentage and calculated as oxides, includes 54.1 mol% Fe2O3, 35.9 mol% MnO, and 10 mol% ZnO, and weighed accordingly; the first additive, according to weight percentage and calculated as oxides, includes 0.30 wt% Co2O3, 0.05 wt% ZrO2, 0.03 wt% V2O5, and 0.15 wt% CaO; and provide the second additive Y3Fe 5- x Al x O 12 Ferrite particles, by weight percentage, contain 0.3 wt%, with an Al substitution amount of [missing information]. x It is 0.18.

[0125] (2) Place the MnZn ferrite main material into a ball mill, add an equal mass of deionized water, and grind the material once. After drying the ball mill material obtained after the first ball milling, add the first additive and the second additive and then ball mill a second time. Add organic binder to the powder after the second ball milling and mix evenly. After granulation, press it into a green embryo. Sinter the material by controlling the temperature and oxygen partial pressure to obtain the composite ferrite material.

[0126] Figure 11 The figure shows the variation of the magnetic permeability of the magnetic ring in Example 8 with a DC magnetic field. The initial magnetic permeability of this magnetic ring is 1555. H μmax It is 145 A / m. H μ100 It is 239 A / m. H μ70 The value is 273 A / m. Compared with Example 7, the use of YIG ferrite nanoparticles with an Al substitution amount of 0.18% for composite formation further improves the saturation magnetic induction intensity of the YIG ferrite nanoparticles. Under the premise of ensuring excellent DC superposition capability, the saturation magnetic induction intensity of the composite ferrite is increased from 494 mT to 499 mT.

[0127] Example 9

[0128] A composite ferrite, prepared by the following steps:

[0129] (1) Prepare the MnZn ferrite main material, which, according to molar percentage and calculated as oxides, includes 54.1 mol% Fe2O3, 36.9 mol% MnO, and 9 mol% ZnO, and weighed accordingly; the first additive, according to weight percentage and calculated as oxides, includes 0.30 wt% Co2O3, 0.05 wt% ZrO2, 0.03 wt% V2O5, and 0.15 wt% CaO; and provide the second additive Y3Fe 5- x Al x O 12 Ferrite particles, by weight percentage, contain 0.3 wt%, with an Al substitution amount of [missing information]. x It is 0.20.

[0130] (2) Place the MnZn ferrite main material into a ball mill, add an equal mass of deionized water, and grind the material once. After drying the ball mill material obtained after the first ball milling, add the first additive and the second additive and then ball mill a second time. Add organic binder to the powder after the second ball milling and mix evenly. After granulation, press it into a green embryo. Sinter the material by controlling the temperature and oxygen partial pressure to obtain the composite ferrite material.

[0131] Figure 12The figure shows the variation of the magnetic permeability of the magnetic ring in Example 9 with a DC magnetic field. The initial magnetic permeability of this magnetic ring is 1552. H μmax It is 145A / m. H μ100 It is 223 A / m. H μ70 The value was 277 A / m. Compared with Example 8, although the DC superposition resistance did not change significantly, the large amount of Al substitution actually reduced the saturation magnetic induction of the YIG ferrite nanoparticles, which in turn caused the saturation magnetic induction of the composite ferrite to drop from 499 mT to 492 mT.

[0132] Comparative Example 3

[0133] A composite ferrite, prepared by the following steps:

[0134] (1) Prepare the MnZn ferrite main material, which, according to molar percentage and calculated as oxides, includes 54.1 mol% Fe2O3, 35.4 mol% MnO, and 10.5 mol% ZnO, and weigh it after calculation; the first additive, according to weight percentage and calculated as oxides, includes 0.30 wt% Co2O3, 0.05 wt% ZrO2, 0.03 wt% V2O5, and 0.15 wt% CaO; and provide the second additive Y3Fe 5- x Al x O 12 Ferrite particles, by weight percentage, contain 0.3 wt%, with an Al substitution amount of [missing information]. x It is 0.24.

[0135] (2) Place the MnZn ferrite main material into a ball mill, add an equal mass of deionized water, and grind the material once. After drying the ball mill material obtained after the first ball milling, add the first additive and the second additive and then ball mill a second time. Add organic binder to the powder after the second ball milling and mix evenly. After granulation, press it into a green embryo. Sinter the material by controlling the temperature and oxygen partial pressure to obtain the composite ferrite material.

[0136] Figure 13 The figure shows the variation of the magnetic permeability of the magnetic ring in Comparative Example 3 with a DC magnetic field. The initial magnetic permeability of this magnetic ring is 1452. H μmax It is 138A / m. H μ100 It is 231 A / m. H μ70The value is 270 A / m. Compared with Examples 7-9, the DC superposition resistance of the sample in this example is not significantly changed. However, the magnetic properties of the YIG ferrite nanoparticles are deteriorated due to the excessive Al substitution, which in turn reduces the initial permeability and saturation magnetic induction of the composite ferrite.

[0137] Performance testing

[0138] The application effect data of the composite ferrites prepared in Examples 1-9 and Comparative Examples 1-3 are shown in Table 2 below.

[0139] Table 2 Performance parameters of composite ferrite

[0140]

[0141] As can be seen from the data in Table 2 above, the simultaneous addition of 0.20~0.40wt% Co2O3 and 0.20~0.40wt% YIG ferrite nanoparticles during the preparation of the composite ferrite based on the embodiments of this application has the best effect on improving the DC superposition resistance of the magnetic ring.

[0142] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a composite ferrite material, characterized in that, Includes the following steps: Based on molar percentage and calculated as oxides, 53.1~55.1 mol% Fe2O3, 34.9~36.9 mol% MnO, and 8~12 mol% ZnO were weighed and mixed to obtain the MnZn ferrite main material; Based on weight percentages and calculated as oxides, 0.20~0.40wt% Co2O3, 0.05wt% ZrO2, 0.03wt% V2O5, and 0.15wt% CaO were weighed and mixed to obtain the first additive; 0.20~0.40wt% YIG ferrite nanoparticles were weighed and used as the second additive. After placing the MnZn ferrite main material into the ball mill, the grinding material is pre-fired, and the ball milling material obtained after one ball milling is dried. After adding the first additive and the second additive, the mixture is ball-milled twice. An organic binder is added to the powder after the second ball milling and mixed evenly. The mixture is then granulated and pressed into a green embryo. The green embryo is then sintered to obtain a composite ferrite material. The sintering process is segmented: the green blank is placed in a tube furnace for sintering, with a slow heating rate of 1.5℃ / min in the range of 50℃ to 500℃, and air is introduced; the heating rate is 2.5℃ / min in the range of 500℃ to 850℃, and air is introduced; the heating rate is 2℃ / min in the range of 850℃ to 1220℃; after reaching 1220℃, it is held for 4 to 8 hours with an oxygen partial pressure of 1.5% to 3.3%; and sintering is carried out in a balanced atmosphere in the cooling section. During the temperature rise range of 850℃ to 1220℃, nitrogen gas is introduced 15 minutes before the temperature reaches 1220℃.

2. The method for preparing a composite ferrite material according to claim 1, characterized in that, YIG ferrite nanoparticles are Y3Fe5O 12 or Y3Fe 5-x Al x O 12 Its component is Y3Fe5O 12 The particle size is less than 100 nm; the composition is Y3Fe 5- x Al x O 12 The particles were prepared by the sol-gel method as follows: Fe(NO3)3 and Y(NO3)3 were dissolved in distilled water and stirred to obtain solution 1, while Al(NO3)3 and citric acid were dissolved and stirred to obtain solution 2; then solution 1 was added dropwise to solution 2 and stirred continuously, and the pH value of the solution was adjusted to 6-7 using ammonia water; ethylene glycol was added dropwise to the mixed solution and heated and stirred until the water evaporated to obtain gel; the temperature was further increased to allow the gel to spontaneously combust into powder, and the powder was sintered at 870~920 ℃ for 4 h to obtain powder with a particle size of less than 100 nm.

3. The method for preparing a composite ferrite material according to claim 1, characterized in that, In the first ball milling, deionized water of equal weight to the MnZn ferrite main material is added, and the ball milling is carried out for more than 1.5 hours; the second ball milling includes a second ball milling for 3.5 hours after the addition of the first additive and the second additive.

4. The method for preparing a composite ferrite material according to claim 1, characterized in that, The pre-firing conditions include pre-firing in an air atmosphere at 890℃~920℃, followed by holding at that temperature for 0.5h~2h.

5. The method for preparing a composite ferrite material according to claim 1, characterized in that, molding... include: After drying the slurry after secondary ball milling, 12wt% PVA adhesive is added, and the mixture is granulated by hand kneading. It is then pressed into shape in a mold under a pressure of 70 MPa.

6. The method for preparing a composite ferrite material according to claim 5, characterized in that, The holding time during the molding process is 20-25 seconds. The molding process includes pressing a ring-shaped green preform, which is 18mm*8mm*3mm in size.

7. A composite ferrite material, characterized in that, The composite ferrite material was prepared by the method described in any one of claims 1 to 6.

8. An application of the composite ferrite material as described in claim 7, characterized in that, Composite ferrite materials are used in electronic components.

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