CN108640670B

CN108640670B - High Bs value and low power loss soft magnetic ferrite material and preparation method of magnetic core

Info

Publication number: CN108640670B
Application number: CN201810386769.XA
Authority: CN
Inventors: 郭皓; 黄刚; 李崇华
Original assignee: China Magnetic Electronic Technology Co ltd
Current assignee: China Magnetic Electronic Technology Co ltd
Priority date: 2018-04-26
Filing date: 2018-04-26
Publication date: 2021-03-02
Anticipated expiration: 2038-04-26
Also published as: CN108640670A

Abstract

The invention provides a preparation method of a soft magnetic ferrite material with high Bs value and low power loss and a magnetic core, wherein a main formula and effective doping are optimized, the soft magnetic ferrite material with high Bs value and low power consumption is developed, the grain size of a final product is 3-4 mu m, the initial magnetic conductivity ui reaches over 2200, the power loss is 380-420 kW/m at the values of 80-120 ℃, 100kHz and 200mTBs value³Bs at 100 ℃ is above 450 mT; the density, the grain size and the porosity of the ferrite material and the distribution of the ferrite material in and among grains are controlled by adopting a multi-section type balanced atmosphere sintering method, so that the microstructure of the soft magnetic ferrite is more effectively controlled, and the main characteristic parameters of the material are ensured to be harmonious and uniform; the final product quality is high, and the production cost is reduced by more than 20%.

Description

High Bs value and low power loss soft magnetic ferrite material and preparation method of magnetic core

Technical Field

The invention relates to a soft magnetic ferrite material, in particular to a soft magnetic ferrite material with high Bs value and low power loss and a preparation method of a magnetic core.

Background

Since the research and development of a soft magnetic ferrite material in 1935 by a Netherlands Phillips laboratory is successful, the history of the soft magnetic ferrite material is over 80 years, and the magnetic property of the ferrite is from the ferrimagnetic property, so that the saturation magnetization Ms of the ferrite is lower than that of metal magnetic property, but the resistivity rho of the ferrite is much higher than that of the metal magnetic property, and the soft magnetic ferrite material has good high-frequency characteristics. In the field of weak current high frequency technology, soft magnetic ferrite has unique advantages. Magnetic cores made of such materials are core components of various inductors, electronic transformers, choke coils, suppressors, filters, and the like. Soft magnetic ferrite materials are listed as "advanced high and new technology industrialization important field guideline (2011) published by the department of national institute of improvement and modification(s), etc., and" advanced high and new technology field directory (2015) published by the national ministry of science and technology "and supported by national emphasis, as basic materials for electronic information technology. The LED power generation system is widely applied to the pillar industry and the emerging industry of computers, household appliances, energy-saving lamps, LEDs, network communication, automobiles, electric vehicles, high-speed rails, wind power, nuclear power generation and the like.

With the continuous and rapid progress of the electronic technology, the ferrite soft magnetic material used therein is required to be higher and higher. In order to meet the material requirements of the new fields of aerospace communication, new energy automobiles, clean energy, LED green illumination, portable electronic equipment and the like for the miniaturization and high direct current superposition characteristics of the magnetic core, magnetic core manufacturers at home and abroad in the magnetic material industry have developed a novel material research and development plan which not only meets the low loss requirement but also has high saturation magnetic flux density. However, the realization of low power consumption and high temperature and Bs at the same time is a difficult point for research and development of soft magnetic ferrite materials, and the electronic market urgently needs such materials which can stably work and efficiently provide conversion power of electronic components.

Compared with the research and development level of high Bs materials of domestic manufacturers, the research and development results of many manufacturers are that the Bs value does not reach the ideal state, the loss is high, or the dependence on a sintering process is high. At present, only a few domestic manufacturers can achieve the Bs value level as follows: the normal temperature is 530mT, and the high temperature is 440 mT.

Disclosure of Invention

In view of this, the present invention provides a soft magnetic ferrite material with high Bs value and low power loss and a method for preparing a magnetic core.

The technical scheme of the invention is realized as follows:

in one aspect, the present invention provides a high Bs value, low power loss soft magnetic ferrite material comprising a main component and an additive component, wherein,

the proportions of the main components are respectively as follows:

Fe₂O₃ 68～72 mol%

MnO 13～17mol%

ZnO 11～15mol%

the proportion of each main component is 100mol percent;

relative to the total amount of the main components, the weight ratio of each additive component is respectively as follows:

CaCO₃ 100～1000PPM

SnO₂ 100～500PPM

MoO₃ 50～100PPM

ZrO₂ 100～500PPM

Bi₂O₃ 50～100PPM

nano SiO₂ 50～100PPM。

The basis of the technical proposalAbove, preferably, the nano SiO₂The particle size of (A) is in the range of 50 to 200 nm.

On the other hand, the invention provides a preparation method of a soft magnetic ferrite core with high Bs value and low power loss, which comprises the following steps,

s1, mixing the main components and the additive components, and performing ball milling, granulation and presintering to obtain a manganese-zinc ferrite material;

and S2, carrying out compression molding and sintering on the manganese-zinc ferrite material obtained in the step S1 to obtain a final product.

On the basis of the above technical solution, preferably, in the step S1, pure water, a dispersant, a binder and a defoaming agent are added in the ball milling process, the particle size distribution is controlled to be 100 to 300 μm, and the weight percentage of the water content is 0.15 to 0.25%.

In addition to the above technical solutions, it is preferable that, in the step S1, a PVA solution of 7 wt% to 10 wt% is added during granulation, and spray drying is adopted.

On the basis of the above technical solution, preferably, in the step S1, the pre-sintering temperature is 950 to 1050 ℃, and the pre-sintering time is 30 to 90 min.

On the basis of the above technical solution, preferably, in the step S2, the sintering process includes,

s2-1, heating from room temperature to 900 ℃ in an atmospheric atmosphere at a heating rate of 0.5-2.0 ℃/min;

s2-2, adjusting the oxygen partial pressure to 0.4-0.5%, and heating up from 900 ℃ to 1200 ℃ at a heating rate of 1.0-3.0 ℃/min;

s2-3, adjusting the oxygen partial pressure to 5-7%, heating up from 1200 ℃ to 1350-1370 ℃ at a heating rate of 3-10 ℃/min, and preserving heat for 4.2-7 h;

s2-4, cooling under the condition of balanced oxygen partial pressure to obtain a sintered density of 4.75-5 kg/m³The magnetic core of (2).

On the basis of the technical scheme, preferably, in the step S2-4, the highest sintering temperature is firstly reduced to 900 ℃, the temperature reduction rate is 2.5-5 ℃/min, and the oxygen partial pressure is controlled to be 0.02% -0.5%; then, the temperature is reduced from 900 ℃ to room temperature at a rate of 1.5-4 ℃/min, and the oxygen partial pressure is controlled to be 0-0.005%.

On the basis of the technical scheme, the grain size of the final product is preferably 3-4 mu m, the initial magnetic conductivity ui reaches over 2200, and the power loss is 380-420 kW/m under the values of 80-120 ℃, 100kHz and 200mT Bs³The Bs at 100 ℃ are above 450 mT.

Compared with the prior art, the preparation method of the soft magnetic ferrite material and the magnetic core with high Bs value and low power loss has the following beneficial effects:

(1) the main formula and effective doping are optimized, the soft magnetic ferrite material with high Bs and low power consumption is developed, the grain size of the final product is 3-4 mu m, the initial magnetic conductivity ui reaches over 2200, and the power loss is 320-420 kW/m under the values of 80-120 ℃, 100kHz and 200mT Bs³Bs at 100 ℃ is above 450 mT;

(2) the density, the grain size and the porosity of the ferrite material and the distribution of the ferrite material in and among grains are controlled by adopting a multi-section type balanced atmosphere sintering method, so that the microstructure of the soft magnetic ferrite is more effectively controlled, and the main characteristic parameters of the material are ensured to be harmonious and uniform;

(3) the final product quality is high, and the production cost is reduced by more than 20%.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

Example 1

The soft magnetic ferrite material of the present embodiment includes a main component and an additive component, wherein,

the proportions of the main components are respectively as follows:

Fe₂O₃ 68mol

MnO 17mol

ZnO 15mol

CaCO₃ 100PPM

SnO₂ 100PPM

MoO₃ 50PPM

ZrO₂ 100PPM

Bi₂O₃ 50PPM

nanometer SiO with particle size range of 50-100 nm₂ 50PPM。

The preparation steps of the soft magnetic ferrite magnetic core with high Bs value and low power loss are as follows:

first, the main components and the additive components are weighed and mixed uniformly.

And secondly, adding pure water, a dispersing agent, an adhesive and a defoaming agent into the mixed material, and performing ball milling, wherein the particle size distribution is controlled to be 100-300 mu m, and the weight percentage of water is 0.15%.

Then, a 7 wt% PVA solution was added to the powder obtained by the ball-milling, and granulated by spray drying.

And then presintering at 950 ℃ in air atmosphere for 30min to obtain the manganese-zinc ferrite material.

And finally, carrying out compression molding on the manganese-zinc ferrite material obtained by pre-sintering, and then sintering under the following conditions to obtain a final product:

s2-1, in the atmosphere, raising the temperature from room temperature to 900 ℃ at the temperature raising rate of 0.5 ℃/min;

s2-2, adjusting the oxygen partial pressure to 0.4%, and heating from 900 ℃ to 1200 ℃ at the heating rate of 1.0 ℃/min;

s2-3, adjusting the oxygen partial pressure to 5%, heating up from 1200 ℃ to 1350 ℃ at the heating rate of 3 ℃/min, and preserving heat for 4.2 h;

s2-4, firstly, reducing the temperature from the highest sintering temperature to 900 ℃, wherein the temperature reduction rate is 2.5 ℃/min, and the oxygen partial pressure is controlled to be 0.02-0.5%; then, the temperature is reduced from 900 ℃ to room temperature at the rate of 1.5 ℃/min, the oxygen partial pressure is controlled to be 0-0.005 percent, and the sintered density is 4.75kg/m³The magnetic core of (2).

Example 2

the proportions of the main components are respectively as follows:

Fe₂O₃ 70 mol

MnO 15mol

ZnO 15mol

CaCO₃ 500PPM

SnO₂ 200PPM

MoO₃ 70PPM

ZrO₂ 300PPM

Bi₂O₃ 70PPM

nano SiO with particle size range of 100-200 nm₂ 70PPM。

And secondly, adding pure water, a dispersing agent, an adhesive and a defoaming agent into the mixed material, and performing ball milling, wherein the particle size distribution is controlled to be 100-300 mu m, and the weight percentage of water is 0.2%.

Then, 8 wt% of PVA solution was added to the powder obtained by the ball milling, and spray drying was used for granulation.

And then presintering at 1000 ℃ for 60min in an air atmosphere to obtain the manganese-zinc ferrite material.

s2-1, in the atmosphere, raising the temperature from room temperature to 900 ℃ at the temperature raising rate of 1.5 ℃/min;

s2-2, adjusting the oxygen partial pressure to 0.4-0.5%, and heating up from 900 ℃ to 1200 ℃ at the heating rate of 2 ℃/min;

s2-3, adjusting the oxygen partial pressure to 5-7%, heating from 1200 ℃ to 1360 ℃ at the heating rate of 6 ℃/min, and keeping the temperature for 5.5 h;

s2-4, firstly, reducing the temperature from the highest sintering temperature to 900 ℃, wherein the temperature reduction rate is 3.5 ℃/min, and the oxygen partial pressure is controlled to be 0.02-0.5%; then, the temperature is reduced from 900 ℃ to room temperature at a rate of 3 ℃/min, the oxygen partial pressure is controlled to be 0-0.005%, and the sintered density is 4.85kg/m³The magnetic core of (2).

Example 3

the proportions of the main components are respectively as follows:

Fe₂O₃ 72 mol

MnO 17mol

ZnO 11mol

CaCO₃ 1000PPM

SnO₂ 500PPM

MoO₃ 100PPM

ZrO₂ 500PPM

Bi₂O₃ 100PPM

nanometer SiO with particle size range of 50-200 nm₂ 100PPM。

And secondly, adding pure water, a dispersing agent, an adhesive and a defoaming agent into the mixed material, and performing ball milling, wherein the particle size distribution is controlled to be 100-300 mu m, and the weight percentage of water is 0.25%.

Then, 10 wt% of PVA solution was added to the powder obtained by the ball milling, and spray drying was used for granulation.

And then presintering at 1050 ℃ in an air atmosphere for 90min to obtain the manganese-zinc ferrite material.

s2-1, in the atmosphere, raising the temperature from room temperature to 900 ℃ at the temperature raising rate of 2.0 ℃/min;

s2-2, adjusting the oxygen partial pressure to be 0.4-0.5%, and heating up from 900 ℃ to 1200 ℃ at a heating rate of 3.0 ℃/min;

s2-3, adjusting the oxygen partial pressure to 7%, heating up from 1200 ℃ to 1370 ℃ at the heating rate of 10 ℃/min, and keeping the temperature for 7 h;

s2-4, firstly, reducing the temperature from the highest sintering temperature to 900 ℃, wherein the temperature reduction rate is 5 ℃/min, and the oxygen partial pressure is controlled to be 0.02-0.5%; then, the temperature is reduced from 900 ℃ to room temperature at a rate of 4 ℃/min, the oxygen partial pressure is controlled to be 0-0.005%, and the sintered density is 4.90kg/m³The magnetic core of (2).

The core obtained in example 2 was tested and the following results were obtained:

as can be seen, the grain size of the final product is 3-4 μm, the initial permeability ui reaches over 2200, and the power loss is 320-420 kW/m at 80-120 ℃, 100kHz and 200mT Bs³The Bs at 100 ℃ are above 450 mT.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A soft magnetic ferrite material with high Bs value and low power loss is characterized in that: the ferrite powder comprises a main component and an additive component, wherein,

the proportions of the main components are respectively as follows:

Fe₂O₃ 68～72 mol%

MnO 13～17mol%

ZnO 11～15mol%

the proportion of each main component is 100mol percent;

CaCO₃ 100～1000PPM

SnO₂ 100～500PPM

MoO₃ 50～100PPM

ZrO₂ 100～500PPM

Bi₂O₃ 50～100PPM

nano SiO₂ 50～100PPM。

2. The high Bs value, low power loss soft magnetic ferrite material of claim 1, wherein: the nano SiO₂The particle size of (A) is in the range of 50 to 200 nm.

3. The method of preparing a high Bs value, low power loss soft magnetic ferrite core of claim 1, wherein: comprises the following steps of (a) carrying out,

4. The method for preparing a high Bs value low power loss soft magnetic ferrite material as claimed in claim 3, wherein: in the step S1, pure water, a dispersing agent, an adhesive and a defoaming agent are added in the ball milling process, the particle size distribution is controlled to be 100-300 mu m, and the weight percentage of water is 0.15-0.25%.

5. The method of claim 3 for preparing a high Bs value, low power loss soft magnetic ferrite core, wherein: in the step S1, a PVA solution of 7 wt% to 10 wt% is added during granulation, and spray drying is adopted.

6. The method of claim 3 for preparing a high Bs value, low power loss soft magnetic ferrite core, wherein: in the step S1, the pre-sintering temperature is 950-1050 ℃, and the pre-sintering time is 30-90 min.

7. The method of claim 3 for preparing a high Bs value, low power loss soft magnetic ferrite core, wherein: in step S2, the sintering process includes,

8. The method of claim 7 for preparing a high Bs value, low power loss soft magnetic ferrite core, wherein: in the step S2-4, the highest sintering temperature is reduced to 900 ℃, the temperature reduction rate is 2.5-5 ℃/min, and the oxygen partial pressure is controlled to be 0.02-0.5%; then, the temperature is reduced from 900 ℃ to room temperature at a rate of 1.5-4 ℃/min, and the oxygen partial pressure is controlled to be 0-0.005%.

9. The method of claim 3 for preparing a high Bs value, low power loss soft magnetic ferrite core, wherein: the grain size of the final product is 3-4 μm, the initial permeability ui reaches over 2200, and the power loss is 320-420 kW/m at 80-120 ℃, 100kHz and 200mT Bs³The Bs at 100 ℃ are above 450 mT.