CN111362680A

CN111362680A - High-frequency low-loss FeMnZnNi ferrite material and preparation method thereof

Info

Publication number: CN111362680A
Application number: CN201910990069.6A
Authority: CN
Inventors: 朱航飞; 张丛; 刘立东; 王国光; 单震
Original assignee: Hengdian Group DMEGC Magnetics Co Ltd
Current assignee: Hengdian Group DMEGC Magnetics Co Ltd
Priority date: 2019-10-17
Filing date: 2019-10-17
Publication date: 2020-07-03

Abstract

The invention relates to the field of an oxygen-iron body material, and discloses a high-frequency low-loss FeMnZnNi ferrite material and a preparation method thereof, aiming at the problems that the power consumption frequency open range of the prior art is smaller and the low loss under the high-frequency condition can not be met, wherein the high-frequency low-loss FeMnZnNi ferrite material comprises a main component and an auxiliary component, wherein the main component comprises 70.5-76.5% of Fe by mass fraction₂O₃0.5 to 5.5 percent of ZnO, 0.5 to 3 percent of NiO and the balance of Mn₃O₄. The preparation method comprises the following steps: ball milling, presintering, granulating and sintering. The quaternary system FeMnZnNi ferrite material provided by the invention has high initial permeability, high saturation magnetic flux density and high Curie temperature, overcomes the defects that the loss of the existing soft magnetic ferrite is high when the frequency is 5MHz, reduces the expensive cost of Ni-Zn ferrite, reduces the volume of a magnetic core and meets the requirement of the design frequency of a transformer developing to high frequency.

Description

High-frequency low-loss FeMnZnNi ferrite material and preparation method thereof

Technical Field

The invention relates to the field of an oxygen-iron body material, in particular to a high-frequency low-loss FeMnZnNi ferrite material and a preparation method thereof.

Background

The soft magnetic ferrite is a functional magnetic material with the most varieties, the most wide application and the most consumption. With the rapid development of modern electronic technology, electronic devices are gradually required to be microminiaturized, miniaturized and lightweight, for example, electronic transformers, the miniaturization of which is limited by the volume of a magnetic core, and the reduction of the volume of the magnetic core is critical for the size reduction of the current electronic transformers, especially in high-power transformer modules.

When the application frequency is below 1MHz, the Mn-Zn ferrite has better performance, but when the application frequency is above 1MHz, the Ni-Zn ferrite material has better performance than the Mn-Zn ferrite, for example, the Ni-Zn ferrite has porosity and high resistivity, so the eddy current loss of the Ni-Zn ferrite is lower, and the Ni-Zn ferrite is very suitable for being used in high frequency. The nickel oxide of the Ni-Zn ferrite raw material is expensive, the manganese oxide of the Mn-Zn ferrite raw material is relatively low in price, the reduction of the power consumption of the ferrite is mainly started from an optimization formula and an improvement preparation method, the solid-phase reaction method is low in cost and suitable for mass production, the intrinsic characteristics of the material can be improved by the optimization formula, the optimization formula is an important means for improving the material performance, and the performance is improved by mainly adjusting the main formula or adding other elements.

Patent No. CN105110785A, entitled "a high-frequency low-loss MnZn ferrite and a preparation method thereof", discloses a high-frequency low-loss MnZn ferrite, which comprises main materials: fe₂O₃：30-40mol％，MnO：36-42mol％，TiO₂: 10-15 mol%, ZnO: the balance; auxiliary materials: CaCO₃：0.25-0.35wt％，V₂O₅：0.04-0.6wt％，Nb₂O₅: 0.02-0.03 wt%. Meanwhile, the preparation method of the high-frequency low-loss MnZn ferrite comprises the steps of preparing a pre-sintered material, preparing a granular material and sintering at a low temperature, wherein the power consumption of the high-frequency low-loss MnZn ferrite disclosed by the patent is less than or equal to 100mW/cm under the condition of 100 ℃ of 1MHz and 30mT³And the power consumption is less than or equal to 200mW/cm under the condition of 3MHz and 10mT at the temperature of 100 DEG C³。

The method has the defects that only the power consumption of 1MHz and 3MHz frequencies is disclosed, the performances of magnetic conductivity, saturation magnetic induction intensity, Curie temperature and the like are not disclosed, the power consumption of higher frequencies is not mentioned, and the low loss under the high-frequency condition cannot be met.

Disclosure of Invention

The invention provides a high-frequency low-loss FeMnZnNi ferrite material and a preparation method thereof, aiming at overcoming the problems that the power consumption frequency open range is smaller and the low loss under the high-frequency condition can not be met in the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

a high-frequency low-loss FeMnZnNi ferrite material comprises a main component and an auxiliary component, wherein the main component contains 70.5-76.5% of Fe by mass fraction₂O₃0.5 to 5.5 percent of ZnO, 0.5 to 3 percent of NiO and the balance of Mn₃O₄The auxiliary components comprise the following components in percentage by weight based on the total weight of the main components: CaCO₃200-1500ppm, V₂O₅200-800ppm ZrO₂100-800ppm, Nb₂O₅100-500ppm of Co₂O₃200 and 1500 ppm.

Incorporation of small amounts of CaCO₃，Ca²⁺Segregation to grain boundary, increase average size of ferrite material grains, improve uniformity, thicken grain boundary, improve initial permeability to a large extent₃The doping amount is increased, the porosity of the material is increased, the grain size becomes uneven, the domain wall is difficult to move, the reaction with other impurities is carried out, another phase is formed on the grain boundary, and the initial permeability is reduced; with CaCO₃The doping amount of the ferrite is increased, the sintering density of the ferrite material is increased firstly and then reduced, and the saturation magnetic induction intensity is also increased firstly and then reduced; the power consumption of the ferrite material is maintained to be decreased and then increased with the increase of the addition amount, so that CaCO₃The amount of (c) to be added needs to be kept within a certain range.

With ZrO₂Increase of addition amount, initial permeability of ferrite and saturation inductionThe strength is increased and then decreased due to ZrO₂The addition of ZrO in a proper amount can make the grain size distribution uniform, increase the average grain size and reduce the porosity, but when the addition amount is too large, abnormal growth of grains can occur, the porosity is increased, the magnetization resistance is increased, and the initial permeability is reduced, so that the addition of ZrO in a proper amount₂The initial magnetic conductivity and the saturation magnetic induction intensity of the ferrite material can reach the highest point, and the loss of the ferrite is reduced.

V₂O₅The addition of the magnetic powder can promote liquid phase sintering, is beneficial to improving the reaction rate along with the increase of the addition amount, promotes the proceeding of solid phase reaction, improves the sintering density of the material, refines crystal grains, reduces the porosity of crystal boundaries and in the crystal grains, improves the resistivity of the crystal boundaries, increases the saturated molecular magnetic moment of unit volume, is beneficial to improving the saturation magnetic induction intensity, is beneficial to uniform growth of the crystal grains and is beneficial to reducing the residual magnetic induction intensity.

Adding appropriate amount of Nb₂O₅Can refine the crystal grains of ferrite material, promote the uniformity of the crystal grains, reduce the porosity in the crystal grains and at the crystal grain boundaries, improve the compactness, increase the initial permeability and the resistivity, reduce the power loss of the material, and when Nb is excessively added₂O₅This results in increased porosity at the grain boundaries, different grain sizes, reduced material density, initial permeability and resistivity, and increased losses.

Proper addition of Co₂O₃By Co²⁺Compensation of magnetocrystalline anisotropy constants increases the initial permeability of the ferrite material and may reduce the remanence of the material, improve the temperature characteristics of permeability, and reduce high frequency losses of the material over a wide temperature range.

Preferably, the ferrite material is a quaternary material in which Ni is located in the main component.

Experiments with the same content of NiO as the main component and additives have shown that ferrite materials have all the best properties as the main component. The addition of NiO can promote the increase of sintering density, can slightly influence the Curie temperature of the ferrite, and the saturation magnetic induction intensity of the ferrite is increased and then decreasedWith the addition of trace amount, the lowest power consumption point of the sample gradually moves to high temperature; proper Co doping in ferrite₂O₃NiO, can obtain better microstructure, improve material density, increase material saturation induction density. The higher lowest loss point and the lower loss can be obtained by adjusting the Co and Ni doping.

Preferably, the FeMnZnNi ferrite material is a high-frequency low-loss quaternary system FeMnZnNi ferrite material, and the technical performance, indexes and parameters are as follows:

a. initial permeability: mu i 700-;

b. magnetic loss: pcv is less than or equal to 1750mw/cm³(T＝100℃，f＝5MHz，B＝30mT)；

c. Saturation magnetic induction: bs is more than or equal to 525mT (25 ℃, H is 1194A/m); bs is more than or equal to 455mT (100 ℃, H is 1194A/m);

d. curie temperature: tc is more than or equal to 280 ℃ (f is 10kHz, and B is less than 0.25 mT).

A preparation method of a high-frequency low-loss FeMnZnNi ferrite material comprises the following preparation steps:

(1) ball milling: carrying out wet ball milling and mixing on the main components, wherein a ball milling medium is low-silicon carbon steel, the mass ratio of materials to the ball milling medium to water is 1:5.8-6.2:1-1.5, and carrying out primary ball milling and then primary spraying to prepare a pre-sintered material;

(2) pre-burning: pre-burning the pre-burning material obtained in the step (1), and then cooling along with a furnace;

(3) and (3) granulation: adding auxiliary components after the step (2) is finished, carrying out secondary ball milling, wherein the mass ratio of the materials to the milling medium to the water is 1:5.8-6.2:1-1.5, carrying out spray granulation, and forming;

(4) and (3) sintering: and sintering.

Preferably, in the step (2), air is used as a pre-sintering atmosphere, the temperature rise rate is 1-3 ℃/min, the pre-sintering temperature is 700-.

Preferably, in the step (3), the grain size of the twice ball milled powder is controlled to be 0.7-1.4 μm, and PVA is added during spray granulation.

Preferably, the addition amount of the PVA is 9-11% of the mass of the mixture of the secondary ball milling.

Preferably, the molding in the step (3) is pressing to form a magnetic ring.

Preferably, the size of the magnetic ring is phi 12.5mm phi 7.5mm 7 mm.

Preferably, in the step (4), the sintering curve is heated to 1000-1200 ℃ at the speed of 1-3 ℃/min, the temperature is kept for 4-8h under the oxygen partial pressure of 0.05-3%, the oxygen content in the temperature reduction stage is 0-2%, and the temperature is reduced to the normal temperature at the speed of 1-5 ℃/min after the temperature reduction stage is finished.

The invention adopts quaternary system FeMnZnNi ferrite material, adds other main components and auxiliary components with reasonable content, strictly controls the technological parameters of the pre-sintering process and the final sintering process of the pre-sintering material, reduces the cost of the Ni-Zn ferrite on the basis of keeping the performances of high initial permeability, saturation magnetic induction intensity, Curie temperature and the like, and simultaneously obtains lower high-frequency (5MHz) loss at 100 ℃, thereby filling the blank that the MnZn ferrite is hardly suitable for the working frequency at home.

Therefore, the invention has the following beneficial effects:

(1) a high-frequency low-loss FeMnZnNi ferrite material and a preparation method thereof are provided, a small amount of Ni element is added into MnZn ferrite to form FeMnZnNi quaternary system ferrite;

(2) on the basis of maintaining the performances of high saturation magnetic flux density, Curie temperature and the like, the loss is lower when T is 100 ℃, f is 5MHz, and B is 30mT (less than or equal to 1750 mw/cm)³) It has excellent comprehensive electromagnetic performance;

(3) the ferrite has high initial permeability, high saturation magnetic flux density and high Curie temperature, and overcomes the defect that the loss of the existing soft magnetic ferrite is high when the frequency is 5 MHz;

(4) the expensive cost of the Ni-Zn ferrite is reduced, the volume of the magnetic core is reduced, and the requirement of the design frequency of the transformer to the development towards high frequency is met.

Detailed Description

The invention is further described with reference to specific embodiments.

Example 1

Is prepared from Fe₂O₃73.5 percent of ZnO1.5 percent, NiO0.5 percent and the balance of Mn₃O₄The four main raw materials are mixed by primary ball milling, pre-sintered at the temperature of 800 ℃ to prepare a pre-sintered material, and auxiliary component CaCO is added₃Is 800ppm, V₂O₅600ppm, ZrO₂Is 400ppm, Co₂O₃1000ppm, Nb₂O₅The content of the slurry is 400ppm, the slurry is subjected to secondary ball milling and uniform mixing, spray granulation (10% of PVA is added), and then the slurry is pressed into a magnetic ring, the size of the magnetic ring is phi 12.5mm phi 7.5mm phi 7mm, according to the preparation method disclosed by the invention (wherein the pre-sintering temperature rise speed is 2 ℃/min, the PVA addition amount during spray granulation is 10% of the mass of the mixture after secondary ball milling, the heat preservation temperature in the sintering process is 1080 ℃, the heat preservation time is 5h, and the oxygen content in the heat preservation stage in the sintering process is 1.5%), after being sintered in a bell jar furnace with strictly controlled atmosphere, the performance is tested, and the results are shown in Table 1.

Example 2

The amount of NiO was increased to 1%, the other components and the preparation method thereof were the same as in example 1, and the results of the performance test are shown in table 1.

Example 3

The amount of NiO was increased to 1.5%, the other ingredients and the preparation method thereof were the same as in example 1, and the results of the performance test are shown in table 1.

Example 4

The amount of NiO was increased to 2%, the other components and the preparation method thereof were the same as in example 1, and the results of the performance test are shown in table 1.

Example 5

The amount of NiO was increased to 2.5%, the other ingredients and the preparation method thereof were the same as in example 1, and the results of the performance test are shown in table 1.

Example 6

The amount of NiO was increased to 3%, the other components and the preparation method thereof were the same as in example 1, and the results of the performance test are shown in table 1.

TABLE 1 initial permeability μ i, saturation induction, magnetic loss Pcv, and Curie temperature Tc of the samples of the examples

Conclusion analysis: from the results of examples 1 to 6, it can be seen that Ni is contained in an amount larger than that of Ni²⁺Is a weakly magnetic ion having a magnetocrystalline anisotropy constant K₁Small, the magnetostriction coefficient lambda s of the ferrite is reduced, and the anisotropy constant K is reduced₁And the magnetostriction coefficient lambdas is closer to 0, the porosity is gradually reduced, the crystal grains are gradually reduced, the density is more compact, and the density is increased, so that the initial permeability of the ferrite is increased, the initial permeability of the ferrite is maximized when the content of NiO is 1.5 percent, and when the content of NiO is more than 1.5 percent, Ni has an overcompensation effect on the magnetostriction coefficient lambdas of the ferrite, but the lambdas of the ferrite is increased, so that the initial permeability of the ferrite is reduced. The ferrite density increased due to the increase of Ni content, saturation magnetic induction Bs increased and reached a maximum value at a NiO content of 1.5%, and after the NiO content > 1.5%, due to Ni²⁺Magnetic moment ratio Mn²⁺Small, resulting in a decrease in saturation magnetization Ms and thus a decrease in saturation magnetic induction Bs.

Example 7

The temperature increase rate of the pre-firing in example 3 was set to 1 ℃/min, the composition and other preparation methods were the same as in example 3, and the results of the performance test were shown in table 2.

Example 8

In example 3, the temperature increase rate of the pre-firing was set to 1.5 ℃/min, the composition and other preparation methods were the same as in example 3, and the results of the performance test were shown in table 2.

Example 9

The temperature increase rate of the pre-firing in example 3 was set to 2.5 ℃/min, the composition and other preparation methods were the same as in example 3, and the results of the performance test were shown in table 2.

Example 10

The temperature increase rate of the pre-firing in example 3 was set to 3 ℃/min, the composition and other preparation methods were the same as in example 3, and the results of the performance test were shown in table 2.

TABLE 2 initial permeability μ i, saturation induction, magnetic loss Pcv, and Curie temperature Tc of the samples of examples 7-10

Conclusion analysis: it can be seen from the results of examples 3 and 7 to 10 that the ferrite starts to undergo a solid phase reaction from 600 ℃ or higher, and that the pre-firing temperature rise rate has a certain influence on the performance of the ferrite, and relatively good performance can be obtained by maintaining the temperature at about 2 ℃/min.

Example 11

The amount of PVA added during spray granulation in example 3 was changed to 5% by mass of the mixture after the secondary ball milling, the other preparation methods were the same as in example 3, and the results of the performance test are shown in table 3.

Example 12

The amount of PVA added during spray granulation in example 3 was changed to 15% of the mass of the mixture after the secondary ball milling, the other preparation methods were the same as in example 3, and the results of the performance tests are shown in table 3.

TABLE 3 initial permeability μ i, saturation induction, magnetic loss Pcv, and Curie temperature Tc of the samples of examples 11-12

Conclusion analysis: combining the example 3 and the examples 11-12, when the PVA content is 5%, the sample has a delamination phenomenon in the forming stage, and the performance is relatively poor, and when the PVA content is 15%, the phenomenon that the glue can not be completely discharged occurs in the sintering process, and the performance is reduced to some extent.

Example 13

Co in the auxiliary component of example 3₂O₃The amount of (2) was reduced to 200ppm, the other components were prepared in the same manner as in example 3, and the results of the performance test are shown in Table 4.

Example 14

Co in the auxiliary component of example 3₂O₃The amount of (2) was reduced to 500ppm, the other components were prepared in the same manner as in example 3, and the results of the performance test are shown in Table 4.

Example 15

Co in the auxiliary component of example 3₂O₃The amount of (2) was increased to 1500ppm, the other components were prepared in the same manner as in example 3, and the results of the performance test are shown in Table 4.

TABLE 4 initial permeability μ i, saturation induction, magnetic loss Pcv, and Curie temperature Tc of the samples of examples 13-15

Conclusion analysis: magnetocrystalline anisotropy constant K of ferrite₁Is negative, Co²⁺To K₁The contribution of the value is positive, Co is added²⁺Negative magnetocrystalline anisotropy constant K for ferrites₁Compensation is carried out by adding Co₂O₃The temperature characteristic of the magnetic permeability can be improved, the magnetization resistance of the material is effectively reduced, the initial magnetic permeability is further improved, and the high-frequency power consumption of the material is reduced. However, when example 3 and examples 13 to 15 were combined, it was found that Co was present₂O₃When the amount of (A) is too large or too small, the magnetic permeability, high frequency power consumption and other properties are deteriorated due to the magnetocrystalline anisotropy constant K₁The value is not equal to 0, only adding proper amount of Co₂O₃The remanence of the material can be reduced, so that the material has better performance.

Example 16

V in the auxiliary component of example 3₂O₅The amount of (2) was reduced to 200ppm, the other components were prepared in the same manner as in example 3, and the results of the performance test are shown in Table 5.

Example 17

V in the auxiliary component of example 3₂O₅The amount of (2) was increased to 400ppm, the other components were prepared in the same manner as in example 3, and the results of the performance test are shown in Table 5.

Example 18

V in the auxiliary component of example 3₂O₅The amount of (2) was increased to 800ppm, the other components were prepared in the same manner as in example 3, and the results of the performance test are shown in Table 5.

TABLE 5 initial permeability μ i, saturation induction, magnetic loss Pcv, and Curie temperature Tc of the samples of examples 16-18

Conclusion analysis: without addition of V₂O₅In the case of ferrite, the grain growth is not uniform, the grain size is large, the porosity is high, the density is small, and V is added₂O₅Then, the solid-phase reaction is promoted, the density is improved, and the crystal boundary and the porosity in the crystal grains are reduced, so that the initial permeability of the ferrite is increased; effectively inhibits the growth and the swallow of crystal grains in the processes of solid-phase reaction and crystal growth, refines the crystal grains, improves the uniformity, gradually improves the grain boundary resistivity, refines the crystal grains, improves the resistivity and reduces the loss. But V₂O₅When the content is too large, part of grains grow abnormally, the grain boundary is reduced, a large amount of grains enter the interior of the grains, and severe retardation is generated on domain wall displacement and magnetic domain rotation, so that the initial permeability is reduced; with simultaneous occurrence of 3Fe³⁺→2Fe²⁺+V⁵⁺Replacement of (2) by Fe²⁺The increase of ions lowers the resistivity of the ferrite, resulting in a decrease in the loss of the ferrite. Combining examples 3, 16-18, it was found that when V₂O₅The addition amount of (B) is preferably 600 ppm.

Example 19

The heat preservation temperature in the sintering process of the embodiment 3 is set to 1070 ℃, the heat preservation time is set to 5h, the components and other preparation methods are the same as the embodiment 3, and the performance test results are shown in table 6.

Example 20

The temperature of the sintering process in example 3 was set to 1090 ℃ and the time of the heat preservation was set to 5 hours, the composition and other preparation methods were the same as those in example 3, and the results of the performance tests are shown in table 6.

Example 21

The heat preservation temperature in the sintering process of the embodiment 3 is set to 1080 ℃, the heat preservation time is set to 4 hours, the components and other preparation methods are the same as the embodiment 3, and the performance test results are shown in table 6.

Example 22

The heat preservation temperature in the sintering process of the embodiment 3 is set to 1080 ℃, the heat preservation time is set to 6h, the components and other preparation methods are the same as the embodiment 3, and the performance test results are shown in table 6.

TABLE 6 initial permeability μ i, saturation induction, magnetic loss Pcv, and Curie temperature Tc of the samples of examples 19-22

Conclusion analysis: the ferrite can generate complex oxidation-reduction reaction and phase change in the sintering process, the sintering process is an important factor directly influencing the microstructure and the performance, and even if a reasonable formula is provided, obvious differences can be presented due to different sintering processes.

The ferrite can be under-sintered at low temperature, complete solid phase reaction can not be ensured, the grain size difference is large, air holes are dispersed in grain boundaries and grains, the initial permeability, the saturation magnetic induction intensity, the loss and other properties are all reduced, the grain size distribution is uniform along with the increase of the sintering temperature, the porosity is reduced, the sintering density reaches the maximum value, the ferrite has higher initial permeability and saturation magnetic induction intensity and lower loss, but the sintering temperature is continuously increased, when the over-sintering is caused by overhigh temperature, the grains can grow abnormally, the sintering density is low, the air holes in the grain boundaries and the grains are rapidly increased, partial impurities reach a molten state, and all properties are reduced by a certain range.

By combining the embodiment 3 and the embodiments 19 to 22, wherein the embodiment 3 is the currently preferred technical scheme, and the performance of the material can be reduced to a certain extent by changing the heat preservation temperature or/and the heat preservation time on the basis.

Example 23

Example 3 the oxygen content at the soak stage in the sintering process was set to 1.1%, the composition and other preparation methods were the same as in example 3, and the performance test results are shown in table 7.

Example 24

The oxygen content at the soak stage in the sintering process of example 3 was set to 1.3%, the composition and other preparation methods were the same as in example 3, and the results of the performance tests are shown in table 7.

Example 25

The oxygen content at the soak stage in the sintering process of example 3 was set to 1.7%, the composition and other preparation methods were the same as in example 3, and the results of the performance tests are shown in table 7.

Example 26

The oxygen content at the soak stage in the sintering process of example 3 was set to 1.9%, the composition and other preparation methods were the same as in example 3, and the results of the performance tests are shown in table 7.

TABLE 7 initial permeability μ i, saturation induction, magnetic loss Pcv, and Curie temperature Tc of the samples of examples 23-26

Conclusion analysis: the sintering process is an oxidation and reduction process, has a close relation with the oxygen partial pressure and the temperature of the surrounding atmosphere, particularly has various valence-variable Mn, presents different valence states under different atmospheres and temperatures, the sintering atmosphere is an important reason for influencing the crystal structure and the performance of the ferrite, the ferrite can generate another phase, a eutectic state and a solid solution due to overhigh, higher, overlow and lower oxygen partial pressure, the initial permeability, the saturation magnetic induction intensity, the loss and other properties of the ferrite are reduced, and the ferrite with the optimal performance can be achieved only by finding the proper oxygen partial pressure.

By combining the embodiment 3 and the embodiments 23-26, on the basis of the embodiment 3, the oxygen content in the heat preservation stage is reduced or increased, and the performance of the material is reduced.

Comparative example 1

The amount of NiO was reduced to 0.5%, the other components and the preparation method thereof were the same as in example 3, and the results of the performance test are shown in Table 8.

Comparative example 2

The amount of NiO was increased to 3.5%, the other ingredients and the preparation method thereof were the same as in example 3, and the results of the performance test are shown in Table 8.

Comparative example 3

Mixing Co₂O₃The amount of (2) was reduced to 0ppm, the other components and the preparation method thereof were the same as in example 3, and the results of the performance test are shown in Table 8.

Comparative example 4

Mixing Co₂O₃The amount of (B) was increased to 2000ppm, the other components and the preparation method thereof were the same as in example 3, and the results of the performance test are shown in Table 8.

Comparative example 5

The heat preservation temperature in the sintering process of the embodiment 3 is set to 1080 ℃, the heat preservation time is set to 3 hours, the components and other preparation methods are the same as the embodiment 3, and the performance test results are shown in table 8.

Comparative example 6

The heat preservation temperature in the sintering process of the embodiment 3 is set to 1080 ℃, the heat preservation time is set to 9h, the components and other preparation methods are the same as the embodiment 3, and the performance test results are shown in table 8.

TABLE 8 initial permeability μ i, saturation induction, magnetic loss Pcv, and Curie temperature Tc of the comparative example samples

Conclusion analysis: when NiO and Co₂O₃Less than or exceeding the scope of the claims of the invention, ferrite to obtain a whole bodyThe performance is poor; when the sintering temperature of the ferrite is lower or higher than the required range, serious under-burning or over-burning occurs, and the performance reduction range of initial permeability, saturation magnetic induction and loss is large.

It can be seen from the data of examples 1-26 and comparative examples 1-6 that the above requirements can be satisfied in all aspects only by the embodiments within the scope of the claims of the present invention, and that an optimized embodiment can be obtained, resulting in a femmnznni ferrite material with optimal performance. The change of the mixture ratio, the replacement/addition/subtraction of raw materials or the change of the feeding sequence can bring corresponding negative effects.

The raw materials and equipment used in the invention are common raw materials and equipment in the field if not specified; the methods used in the present invention are conventional in the art unless otherwise specified.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, alterations and equivalents of the above embodiments according to the technical spirit of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. The high-frequency low-loss FeMnZnNi ferrite material is characterized by comprising a main component and an auxiliary component, wherein the main component contains 70.5 to 76.5 percent of Fe by mass fraction₂O₃0.5 to 5.5 percent of ZnO, 0.5 to 3 percent of NiO and the balance of Mn₃O₄The auxiliary components comprise the following components in percentage by weight based on the total weight of the main components: CaCO₃200-1500ppm, V₂O₅200-800ppm ZrO₂100-800ppm, Nb₂O₅100-500ppm of Co₂O₃200 and 1500 ppm.

2. A high frequency low loss femznni ferrite material as claimed in claim 1, wherein the ferrite material is a quaternary material with Ni in the main component.

3. The high-frequency low-loss FeMnZnNi ferrite material as claimed in claim 1, wherein the FeMnZnNi ferrite material is a high-frequency low-loss quaternary system FeMnZnNi ferrite material, and the technical properties, indexes and parameters achieved are as follows:

a. initial permeability: μ i = 700-;

b. magnetic loss: pcv is less than or equal to 1750mw/cm³（T=100℃，f=5MHz，B=30mT）；

c. Saturation magnetic induction: bs is more than or equal to 525mT (25 ℃, H = 1194A/m); bs is more than or equal to 455mT (100 ℃, H = 1194A/m);

d. curie temperature: tc is more than or equal to 280 ℃ (f =10kHz, B <0.25 mT).

4. A method for preparing a high frequency low loss femznni ferrite material as claimed in any one of claims 1 to 3, comprising the steps of:

(4) and (3) sintering: and sintering.

5. The method for preparing FeMnZnNi ferrite material with high frequency and low loss as claimed in claim 4, wherein in the step (2), air is used as presintering atmosphere, the temperature rise rate is 1-3 ℃/min, the presintering temperature is 700-1000 ℃, and the temperature is preserved for 1-4h and then cooled along with the furnace.

6. The method as claimed in claim 4, wherein the grain size of the ball milled powder after the second time in step (3) is controlled to 0.7-1.4 μm, and PVA is added during spray granulation.

7. The method for preparing FeMnZnNi ferrite material with high frequency and low loss as claimed in claim 6, wherein the amount of PVA added is 9-11% of the mass of the mixture of the secondary ball milling.

8. The method for preparing a high-frequency low-loss FeMnZnNi ferrite material as claimed in claim 4, wherein the molding in step (3) is pressing into a magnetic ring.

9. The method as claimed in claim 8, wherein the size of the magnetic ring is 12.5mm x 7.5mm x 7 mm.

10. The method as claimed in claim 4, wherein the sintering curve in step (4) is raised to 1000-1200 ℃ at a rate of 1-3 ℃/min, the temperature is maintained at 0.05-3% oxygen partial pressure for 4-8h, the oxygen content in the temperature reduction stage is 0-2%, and the temperature is reduced to normal temperature at a rate of 1-5 ℃/min after the temperature reduction stage.