Wide-temperature broadband MnZn ferrite material as well as preparation method and application thereof

Abstract

The invention provides a wide-temperature broadband MnZn ferrite material and a preparation method and application thereof, and belongs to the technical field of ferrite materials, the wide-temperature broadband MnZn ferrite material comprises a main crystal phase and a doped crystal phase, the main crystal phase is MnZn ferrite with a spinel structure, the chemical formula of the MnZn ferrite is MnxZn (1-x) ZryFe (2-y) O4, 0.7 lt; xlt; 0, 0.8, 0.04 lt; yt; Yt; 0.06 part of the composition; the doped crystal phase is prepared from the following components in parts by mass: 0.04 to 0.06 part of BST (Barium Styrene Titanate), 0.2 to 0.3 part of CeFeO3, 0.1 to 0.2 part of CaCO3, 0.01 to 0.05 part of ZrO2, 0.2 to 0.4 part of Bi2O3 and 3 to 5 parts of Co2O3. By improving the chemical composition of the magnetic core material, the developed MnZn ferrite material can still keep stable magnetic performance under high-temperature and high-frequency conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of ferrite materials, and particularly relates to a MnZn ferrite material with wide temperature and wide frequency, and a preparation method and application thereof. Background Art

[0002] With the rapid development of fields such as cloud computing, big data, and artificial intelligence, the demand for high-performance magnetic core materials by network servers is increasing day by day. Network servers have continuously higher requirements for the performance and stability of magnetic core materials under high-temperature, high-frequency, and high-load operating environments. In the research and development of wide-temperature, wide-frequency, and high-saturation magnetic induction intensity magnetic core materials for the new generation of network servers, several key "neck-sticking" technical problems are faced, including the optimization problem of high-frequency characteristics, the adaptability problem in a wide temperature range, the problem of balancing high saturation magnetic induction intensity and low loss, and the manufacturing process problem. Summary of the Invention

[0003] In view of the technical problems existing in the background art, the present application provides a MnZn ferrite material with wide temperature and wide frequency, and a preparation method and application thereof, aiming to solve the problems of optimizing high-frequency characteristics, adapting to a wide temperature range, balancing high saturation magnetic induction intensity and low loss, and the manufacturing process problem.

[0004] In a first aspect, an embodiment of the present application provides a MnZn ferrite material with wide temperature and wide frequency, including a main crystal phase and a doped crystal phase. The main crystal phase is a MnZn ferrite with a spinel structure, and the chemical formula of the MnZn ferrite is Mn x Zn 1-x Zr y Fe 2- y O4, where 0.7 < x < 0.8 and 0.04 < y < 0.06; the doped crystal phase, by mass, includes 0.04 - 0.06 parts of BST, 0.2 - 0.3 parts of CeFeO3, 0.1 - 0.2 parts of CaCO3, 0.01 - 0.05 parts of ZrO2, 0.2 - 0.4 parts of Bi2O3, and 3 - 5 parts of Co2O3.

[0005] In some embodiments, BST is Ba a Sr 1-a TiO3, where 0.3 < a < 0.5.

[0006] In some embodiments, the grain size of the MnZn ferrite material is 0.6 - 0.8 μm.

[0007] In a second aspect, an embodiment of the present application provides a preparation method of a MnZn ferrite material with wide temperature and wide frequency, including the following steps:

[0008] Using Fe2O3, Mn3O4, ZrO2, and ZnO as raw materials, in accordance with Mnx Zn 1-x Zr y Fe 2-y Weigh and proportion the raw materials of each component, mix them after primary ball milling to obtain mixed powder;

[0009] Press the mixed powder into a block, pre-sinter it in an N2 atmosphere to obtain MnZn ferrite powder with a spinel structure;

[0010] Crush the MnZn ferrite powder, mix it with BST, CeFeO3, CaCO3, ZrO2, Bi2O3 and Co2O3, and then perform secondary ball milling to obtain doped ferrite powder;

[0011] Mix the doped ferrite powder with a binder, granulate it, and then press it into a green body;

[0012] Sinter the green body to obtain MnZn ferrite material.

[0013] In some embodiments, zirconium balls are used as the ball milling medium for primary ball milling. The mass ratio of the raw material, zirconium balls and water is 1:3:1.5. The ball milling time is 2 - 3 h, the ball milling speed is 240 - 250 r / min, and the particle size of the mixed powder obtained after primary ball milling is 1 - 1.4 μm.

[0014] In some embodiments, zirconium balls are used as the ball milling medium for secondary ball milling. High-pressure ball milling is carried out for 8 - 10 h in an N2 atmosphere, the ball milling speed is 350 - 450 r / min, and the particle size of the doped ferrite powder obtained after secondary ball milling is 0.3 - 0.5 μm.

[0015] In some embodiments, the pre-sintering temperature is 800 - 900 °C and the pre-sintering time is 2 - 3 h.

[0016] In some embodiments, the pressing pressure is 5 - 7 MPa and the pressure holding time is 10 - 15 s.

[0017] In some embodiments, the sintering process includes the following steps:

[0018] Heating stage: 25 °C - 600 °C, heating rate 1 °C / min, holding at 600 °C for 1 h, 600 °C - 900 °C, heating rate 2.5 °C / min, 900 °C - 1250 °C, heating rate 2.5 °C / min, carried out under balanced oxygen partial pressure;

[0019] Sintering stage: holding at 1250 °C for 15 min, 1250 °C - 1150 °C, cooling rate 3 °C / min, holding at 1150 °C for 3 h, oxygen partial pressure PO2 = 0.20 atm;

[0020] Cooling stage: 1150°C to 900°C, cooling rate 3°C / min, 900°C to room temperature, furnace cooling, carried out using balanced oxygen partial pressure.

[0021] In a third aspect, an embodiment of the present application provides an application of a MnZn ferrite material with wide temperature and wide frequency in the field of network servers.

[0022] Different from the prior art solutions, the beneficial effects of the present application include:

[0023] In the present application, by optimizing the molar ratio of Mn and Zn in the MnZn ferrite material, its high-frequency loss is reduced; Zr is introduced into the main crystal phase 4+ , increasing the resistivity of the MnZn ferrite, thereby reducing the high-frequency eddy current loss; doping BST and CeFeO3 in the MnZn ferrite, BST can provide a high dielectric constant in the low-frequency band, while CeFeO3 can exert its dispersion characteristics in the high-frequency band, thereby improving the broadband dielectric properties of the composite material, enabling broadband coverage from low frequency to high frequency. BST can also form an insulating layer at the grain boundaries of the MnZn ferrite, suppressing the grain boundary leakage current at high temperatures, reducing the eddy current loss, and improving the high-temperature stability of the MnZn ferrite material; Co doping can increase the saturation magnetic induction intensity and initial magnetic permeability of the MnZn ferrite material and reduce the high-frequency loss. By improving the chemical composition of the magnetic core material, the developed MnZn ferrite material can still maintain stable magnetic properties under high-temperature and high-frequency conditions.

[0024] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the following specific embodiments of the present application are specifically given. Specific Embodiments

[0025] The embodiments of the technical solution of the present application will be described in detail below. The following embodiments are only used to illustrate the technical solution of the present application more clearly, so they are only examples and cannot be used to limit the protection scope of the present application.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application are intended to cover non-exclusive inclusion.

[0027] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality" is more than two, unless otherwise specifically defined.

[0028] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0029] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0030] In the description of the embodiments of the present application, the term "a plurality" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0031] In the high-temperature, high-frequency, and high-load operating environment of network servers, the requirements for the performance and stability of magnetic core materials are continuously increasing. In the research and development of wide-temperature, wide-frequency, and high-saturation magnetic induction intensity magnetic core materials for a new generation of network servers, several key "bottleneck" technical problems are faced, including the optimization of high-frequency characteristics, the adaptability of wide temperature ranges, the balance between high saturation magnetic induction intensity and low loss, and manufacturing processes.

[0032] To solve the technical problems, the present application provides a wide-temperature and wide-frequency MnZn ferrite material, its preparation method, and application. Among them, by improving the chemical composition of the magnetic core material, the developed MnZn ferrite material can still maintain stable magnetic properties under high-temperature and high-frequency conditions.

[0033] In a first aspect, an embodiment of the present application provides a wide-temperature and wide-frequency MnZn ferrite material, including a main crystal phase and a doped crystal phase. The main crystal phase is MnZn ferrite with a spinel structure, and the chemical formula of MnZn ferrite is Mn x Zn 1-x Zr y Fe 2- yO4, where 0.7 < x < 0.8 and 0.04 < y < 0.06; the doped crystal phase, by mass, comprises 0.04 - 0.06 parts of BST, 0.2 - 0.3 parts of CeFeO3, 0.1 - 0.2 parts of CaCO3, 0.01 - 0.05 parts of ZrO2, 0.2 - 0.4 parts of Bi2O3, and 3 - 5 parts of Co2O3.

[0034] In the technical solution of the embodiment of the present application, the molar ratio of Mn 2+ and Zn 2+ within the range of (0.7 - 0.8) : (0.2 - 0.3) results in the lowest high - frequency loss of MnZn ferrite.

[0035] On this basis, Zr is introduced into the main crystal phase 4+ , when the addition amount of Zr 4+ is between 0.04 and 0.06, it will enter the MnZn ferrite lattice after ball - milling and pre - sintering, replace part of Fe 3+ , and bind Fe 2+ , increase the resistivity of MnZn ferrite, thereby reducing the high - frequency eddy current loss; if the addition amount of Zr 4+ is too large, it will affect the grain growth, produce more abnormally grown grains, resulting in uneven grain size.

[0036] Functions of doped BST and CeFeO3: The spinel has a relatively low dielectric constant and is difficult to meet the requirements of device miniaturization. The BST perovskite has a high dielectric constant, which can complement the low loss of MnZn ferrite with a spinel structure, inhibit high - frequency loss, achieve dielectric regulation with high dielectric constant, low loss, and wide - frequency stability, making it suitable for miniaturized high - frequency devices; BST can form an insulating layer at the grain boundaries of MnZn ferrite, inhibit the grain - boundary leakage current at high temperatures, reduce the eddy current loss, and the piezoelectric effect of BST can partially offset the magnetostrictive stress of MnZn ferrite, reduce the pinning of magnetic domain walls at high temperatures, and maintain a high magnetic permeability. BST has a high dielectric constant in the low - frequency and medium - frequency ranges, while CeFeO3 shows good dispersion characteristics in the high - frequency range. Combining the two can achieve wide - frequency coverage from low frequency to high frequency. For example, in the composite material, BST can provide a high dielectric constant in the low - frequency band, while CeFeO3 can exert its dispersion characteristics in the high - frequency band, thereby improving the wide - frequency dielectric properties of the composite material.

[0037] Functions of doped ZrO2: Zr 4+ can occupy the grain boundaries, inhibit the high - temperature grain - boundary diffusion, reduce the attenuation of magnetic permeability, maintain the stability of high - temperature magnetic permeability, and reduce the power loss at high temperatures.

[0038] Effect of Co2O3 doping: Doping BST and CeFeO3 will cause a decrease in the initial permeability. Co doping can increase the saturation magnetic induction intensity and the initial permeability, and reduce the high-frequency loss.

[0039] Effect of Bi2O3 doping: During high-temperature sintering, Zn evaporation will occur, leading to composition segregation and the formation of a high-loss second phase. Adding Bi2O3 can reduce the sintering temperature, inhibit Zn volatilization, and avoid the degradation of the MnZn ferrite structure.

[0040] In some embodiments, BST is Ba a Sr 1-a TiO3, where 0.3 < a < 0.5.

[0041] In the technical solution of the embodiment of the present application, by regulating the content of Sr, the temperature stability of BST can be broadened, and at the same time, its dielectric constant can be adjusted to improve the high-temperature stability of the MnZn ferrite material.

[0042] In some embodiments, the grain size of the MnZn ferrite material is 0.6 - 0.8 μm.

[0043] Second, the embodiment of the present application provides a preparation method of a wide-temperature and wide-frequency MnZn ferrite material, including the following steps:

[0044] Using Fe2O23, Mn3O4, ZrO2, and ZnO as raw materials, weighing and proportioning the raw materials according to Mn x Zn 1-x Zr y Fe 2-y O4, mixing after primary ball milling to obtain a mixed powder;

[0045] Pressing the mixed powder into a block and pre-sintering it in an N2 atmosphere to obtain a MnZn ferrite powder with a spinel structure;

[0046] Crushing the MnZn ferrite powder and mixing it with BST, CeFeO3, CaCO3, ZrO2, Bi2O3, and Co2O3, and then performing secondary ball milling to obtain a doped ferrite powder;

[0047] Mixing the doped ferrite powder with a binder, granulating, and pressing it into a green body;

[0048] Sintering the green body to obtain a MnZn ferrite material.

[0049] In some embodiments, zirconium balls are used as the ball milling medium for primary ball milling. The mass ratio of the raw materials, zirconium balls, and water is 1:3:1.5. The ball milling time is 2 - 3 h, the ball milling speed is 240 - 250 r / min, and the particle size of the mixed powder obtained after primary ball milling is 1 - 1.4 μm.

[0050] In some embodiments, zirconium balls are used as the ball milling medium for secondary ball milling. High-pressure ball milling is carried out for 8 - 10 h in an N2 gas atmosphere at a ball milling speed of 350 - 450 r / min. The particle size of the doped ferrite powder obtained after secondary ball milling is 0.3 - 0.5 μm.

[0051] In some embodiments, the pre-sintering temperature is 800 - 900 °C and the pre-sintering time is 2 - 3 h.

[0052] In some embodiments, the pressing pressure is 5 - 7 MPa and the pressure holding time is 10 - 15 s.

[0053] In some embodiments, the sintering process includes the following steps:

[0054] Heating stage: from 25 °C to 600 °C, the heating rate is 1 °C / min, hold at 600 °C for 1 h, from 600 °C to 900 °C, the heating rate is 2.5 °C / min, from 900 °C to 1250 °C, the heating rate is 2.5 °C / min, carried out with balanced oxygen partial pressure;

[0055] Sintering stage: hold at 1250 °C for 15 min, from 1250 °C to 1150 °C, the cooling rate is 3 °C / min, hold at 1150 °C for 3 h, oxygen partial pressure PO2 = 0.20 atm;

[0056] Cooling stage: from 1150 °C to 900 °C, the cooling rate is 3 °C / min, from 900 °C to room temperature, furnace cooling, carried out with balanced oxygen partial pressure.

[0057] In the technical solution of the embodiments of the present application, the doped ferrite powder after high-pressure ball milling has high activity. The two-step low-temperature sintering is adopted. First, quickly heat up to 1250 °C to rapidly reach the critical densification temperature, achieve rapid densification through surface energy driving, eliminate large pores, form a dense skeleton, reduce the driving force for subsequent grain boundary migration, and then hold at 1150 °C to complete the closure of residual pores by volume diffusion, while freezing grain boundary movement, so that the final grain size is controlled within 0.6 - 0.8 μm. Compared with single-step sintering, the grain uniformity of the two-step method is improved and the eddy current loss is reduced. High density, fine grains and low loss can be achieved simultaneously by this method, which is suitable for applications such as high-frequency power inductors.

[0058] In a third aspect, the embodiments of the present application provide an application of a MnZn ferrite material with wide temperature and wide frequency in the field of network servers.

[0059] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present application, and should not be construed as a limitation of the present application. For those without specific technologies or conditions noted in the embodiments, the technologies or conditions described in the literature in this field or according to the product specifications are followed. For reagents or instruments without the manufacturer noted, they are all conventional products that can be obtained through commercial purchases.

[0060] I. Preparation Method

[0061] Example 1

[0062] A preparation method of a MnZn ferrite material with wide temperature and wide frequency includes the following steps:

[0063] Using Fe2O3, Mn3O4, ZrO2, and ZnO as raw materials, according to Mn 0.7 Zn 0.3 Zr 0.06 Fe 1.94 O4 for metering and batching each component of the raw materials, mixing after primary ball milling to obtain a mixed powder. Zirconium balls are used as the ball milling medium in the primary ball milling. The mass ratio of the raw materials, zirconium balls, and water is 1:3:1.5. The ball milling time is 2 h, the ball milling speed is 250 r / min, and the particle size of the mixed powder obtained after primary ball milling is 1 - 1.4 μm.

[0064] Press the mixed powder into a block and pre - sinter it in an N2 atmosphere. The pre - sintering temperature is 800 °C and the pre - sintering time is 3 h to obtain a MnZn ferrite powder with a spinel structure.

[0065] Crush the MnZn ferrite powder and mix it with 0.04 parts of BST, 0.3 parts of CeFeO3, 0.1 parts of CaCO3, 0.05 parts of ZrO2, 0.2 parts of Bi2O3, and 5 parts of Co2O3, and then perform secondary ball milling to obtain a doped ferrite powder, where BST is Ba 0.3 Sr 0.7 TiO3. Zirconium balls are used as the ball milling medium in the secondary ball milling. High - pressure ball milling is carried out for 10 h in an N2 gas atmosphere, and the ball milling speed is 350 r / min. The particle size of the doped ferrite powder obtained after secondary ball milling is 0.3 - 0.5 μm.

[0066] Mix the doped ferrite powder with a binder, granulate it, and then press it into a green body. The pressing pressure is 7 MPa and the pressure - holding time is 10 s;

[0067] Sinter the green body to obtain a MnZn ferrite material.

[0068] The sintering process includes the following steps:

[0069] Heating stage: from 25°C to 600°C, heating rate 1°C / min, hold at 600°C for 1 h, from 600°C to 900°C, heating rate 2.5°C / min, from 900°C to 1250°C, heating rate 2.5°C / min, carried out under balanced oxygen partial pressure;

[0070] Sintering stage: hold at 1250°C for 15 min, from 1250°C to 1150°C, cooling rate 3°C / min, hold at 1150°C for 3 h, oxygen partial pressure PO2 = 0.20 atm;

[0071] Cooling stage: from 1150°C to 900°C, cooling rate 3°C / min, from 900°C to room temperature, furnace cooling, carried out under balanced oxygen partial pressure.

[0072] Example 2

[0073] The difference between Example 2 and Example 1 is that Fe2O3, Mn3O4, ZrO2 and ZnO are used as raw materials, and the metering and batching of each component raw material are carried out according to Mn 0.8 Zn 0.2 Zr 0.04 Fe 1.96 O4.

[0074] The MnZn ferrite powder is crushed and then mixed with 0.06 parts of BST, 0.2 parts of CeFeO3, 0.2 parts of CaCO3, 0.01 parts of ZrO2, 0.4 parts of Bi2O3 and 3 parts of Co2O3, and then subjected to secondary ball milling.

[0075] Other steps are the same as those in Example 1.

[0076] Comparative Example 1

[0077] The difference between Comparative Example 1 and Example 1 is that the main crystal phase in Comparative Example 1 is Mn 0.7 Zn 0.3 Fe2O4.

[0078] Comparative Example 2

[0079] The difference between Comparative Example 2 and Example 1 is that BST is not added to the doped crystal phase in Comparative Example 2.

[0080] Comparative Example 3

[0081] The difference between Comparative Example 3 and Example 1 is that CeFeO3 is not added to the doped crystal phase in Comparative Example 3.

[0082] Comparative Example 4

[0083] The difference between Comparative Example 4 and Example 1 is that Co2O3 is not added to the doped crystal phase in Comparative Example 4.

[0084] Comparative Example 5

[0085] The difference between Comparative Example 5 and Example 1 is that in the doped crystal phase of Comparative Example 5, Ba 0.3 Sr 0.7 TiO3 is replaced by BaTiO3.

[0086] Comparative Example 6

[0087] The difference between Comparative Example 6 and Example 1 is that the sintering stage in the sintering process of Comparative Example 6 is: holding at 1250°C for 3 h, and the oxygen partial pressure PO2 = 0.20 atm.

[0088] II. Test Method

[0089] The initial permeability, loss per unit volume, and resistance of the MnZn ferrite material were respectively detected according to the standard IEC 60401-3, and the initial permeability was detected by the impedance analysis method.

[0090] The detection conditions for the loss per unit volume P are: 100°C, 3 MHz, 30 mT and room temperature, 3 MHz, 30 mT.

[0091] III. Analysis of Test Results of Each Example and Comparative Example

[0092] The initial permeability, loss per unit volume, and resistivity of each example and comparative example were detected, and the detection results are shown in Table 1 below.

[0093] Table 1 Electromagnetic Performance Detection Data of Each Example and Comparative Example

[0094]

[0095] As can be seen from Table 1, the MnZn ferrite material with wide temperature and wide frequency prepared in the examples of the present application has low loss per unit volume under high temperature and high frequency conditions, and relatively high initial permeability and resistivity, and is suitable for the new generation of network servers. In Comparative Example 1, Zr was not added to the main crystal phase, resulting in a decrease in its resistivity and an increase in the loss per unit volume at high temperatures; in Comparative Example 2, BST was not added, the resistivity decreased significantly, and the loss per unit volume increased significantly under high frequency conditions; in Comparative Example 3, CeFeO3 was not added, the loss per unit volume under normal temperature and high frequency conditions was less than that of Comparative Example 2, and the loss per unit volume at high temperature and high frequency was greater than that of Comparative Example 2, indicating that the stability of the MnZn ferrite material under high temperature and high frequency conditions can be improved only by the synergistic effect of BST and CeFeO3; in Comparative Example 4, Co2O3 was not added, and the initial permeability decreased significantly; in Comparative Example 5, in the doped crystal phase, Ba 0.3 Sr 0.7Replacing TiO3 with BaTiO3 increases the loss per unit volume under high-temperature conditions; in Comparative Example 6, the electromagnetic properties are significantly lower in the case of one-time high-temperature sintering than in the case of two-time sintering.

[0096] It should be noted that the present application is not limited to the above embodiments. The above embodiments are only examples, and embodiments having the same constitution and the same effect as the technical idea within the scope of the technical solution of the present application are included in the technical scope of the present application. In addition, within the scope not departing from the gist of the present application, various modifications that can be conceived by those skilled in the art to the embodiments and other embodiments constructed by combining some constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A MnZn ferrite material with wide temperature and wide frequency, characterized in that, It includes a main crystal phase and a doped crystal phase. The main crystal phase is MnZn ferrite with a spinel structure, and the chemical formula of the MnZn ferrite is Mn x Zn 1-x Zr y Fe 2-y O4, where 0.7 < x < 0.8 and 0.04 < y < 0.

06. By mass, the doped crystal phase includes 0.04 - 0.06 parts of BST, 0.2 - 0.3 parts of CeFeO3, 0.1 - 0.2 parts of CaCO3, 0.01 - 0.05 parts of ZrO2, 0.2 - 0.4 parts of Bi2O3, and 3 - 5 parts of Co2O3.

2. The MnZn ferrite material with wide temperature and wide frequency range according to claim 1, characterized in that, The BST is Ba a Sr 1-a TiO3, where 0.3 < a < 0.

5.

3. The MnZn ferrite material with wide temperature and wide frequency according to claim 1, characterized in that, The grain size of the MnZn ferrite material is 0.6 - 0.8 μm.

4. The preparation method of the MnZn ferrite material with wide temperature and wide frequency according to any one of claims 1 to 3, characterized in that, It includes the following steps: Using Fe2O3, Mn3O4, ZrO2 and ZnO as raw materials, according to Mn x Zn 1-x Zr y Fe 2-y O4 to carry out the metering and batching of each component of the raw materials, mixing after primary ball milling to obtain a mixed powder; Press the mixed powder into a block and pre-burn it in an N2 atmosphere to obtain MnZn ferrite powder with a spinel structure; Crush the MnZn ferrite powder, mix it with BST, CeFeO3, CaCO3, ZrO2, Bi2O3 and Co2O3, and then perform secondary ball milling to obtain doped ferrite powder; Mix the doped ferrite powder with a binder, granulate it, and then press it into a green body; Sinter the green body to obtain the MnZn ferrite material.

5. The preparation method of the MnZn ferrite material with wide temperature and wide frequency according to any one of claims 4, characterized in that, For the primary ball milling, zirconium balls are used as the ball milling medium. The mass ratio of the raw material, zirconium balls and water is 1:3:1.

5. The ball milling time is 2 - 3 h, and the ball milling speed is 240 - 250 r / min. The particle size of the mixed powder obtained after the primary ball milling is 1 - 1.4 μm.

6. The preparation method of the MnZn ferrite material with wide temperature and wide frequency according to any one of claims 4, characterized in that, For the secondary ball milling, zirconium balls are used as the ball milling medium. It is high-pressure ball milled in an N2 atmosphere for 8 - 10 h, and the ball milling speed is 350 - 450 r / min. The particle size of the doped ferrite powder obtained after the secondary ball milling is 0.3 - 0.5 μm.

7. The preparation method of the MnZn ferrite material with wide temperature and wide frequency according to any one of claims 4, characterized in that The pre-burning temperature is 800 - 900 °C, and the pre-burning time is 2 - 3 h.

8. The preparation method of the MnZn ferrite material with wide temperature and wide frequency according to any one of claims 4, characterized in that The pressure for pressing is 5 - 7 MPa, and the pressure holding time is 10 - 15 s.

9. The preparation method of the MnZn ferrite material with wide temperature and wide frequency according to claim 4, characterized in that, The sintering process includes the following steps: Heating stage: from 25 °C to 600 °C, the heating rate is 1 °C / min, hold at 600 °C for 1 h, from 600 °C to 900 °C, the heating rate is 2.5 °C / min, from 900 °C to 1250 °C, the heating rate is 2.5 °C / min, and it is carried out with a balanced oxygen partial pressure; Sintering stage: hold at 1250 °C for 15 min, from 1250 °C to 1150 °C, the cooling rate is 3 °C / min, hold at 1150 °C for 3 h, and the oxygen partial pressure PO2 = 0.20 atm; Cooling stage: from 1150 °C to 900 °C, the cooling rate is 3 °C / min, from 900 °C to room temperature, cool with the furnace, and it is carried out with a balanced oxygen partial pressure.

10. Application of a MnZn ferrite material with wide temperature and wide frequency according to claim 1 in the field of network servers.

Images