CN1749209A - High saturation magnetic flux density, low loss manganese zinc ferrite material and preparation method thereof - Google Patents

Abstract

The present invention discloses high saturated magnetic flux density and low loss manganese manganese-zinc ferrite material and its preparation process. The manganese-zinc ferrite material contains: Fe2O3 52-54 mol%, MnO 33-40 mol%, ZnO 8-13 mol%, supplementary components CaCO3 100-600 ppm, SiO2 50-300 ppm and other metal oxides. The preparation process includes the steps of: mixing material, pre-sintering, adding supplementary components, secondary ball milling, forming and sintering. The supplementary components are common oxide grains, and this result in easy adding and low cost. The preparation process of the manganese-zinc ferrite material has relatively low pre-sintering and sintering temperature and relaxed requirement on sintering apparatus, may be completed in common vacuum sintering furnace, and easily realized in industrial production.

Description

High saturation magnetic flux density, low loss manganese zinc ferrite material and preparation method thereof

technical field

The invention relates to a manganese-zinc ferrite material with high saturation magnetic flux density and low loss and a preparation method thereof.

Background technique

Manganese-zinc ferrite materials are currently widely used in electronic equipment components such as communications, electronic computers, televisions and various digital products, and are the largest type of soft ferrite materials in mass production. Among them, power manganese-zinc ferrite is the largest classification of manganese-zinc ferrite, and its main application is to prepare the main transformer of various high-frequency switching power supplies. The main development trend of switching power supply is miniaturization and low loss, which requires that the MnZn ferrite used as the core of the main transformer should have higher saturation flux density and lower power consumption.

In recent years, digital cameras, digital video cameras and mobile communication devices have become more and more popular in people's daily life. These devices usually work below 45°C, so the optimum operating temperature of various internal electronic components is required to be within Below 45°C, switching power supply is no exception. And this requires the manganese-zinc ferrite material in the main transformer of the switching power supply to have the lowest power consumption at about 45°C. Therefore, the development of manganese zinc ferrite with the lowest power consumption and high saturation magnetic flux density at about 45°C has a very broad market application prospect.

At present, the temperature range of the lowest power consumption of most power MnZn ferrites is generally within 60-100°C, and the power consumption value under the test conditions of 100kHz and 200mT is generally greater than 300kW/m ³ . In order to adapt to the development trend of digital equipment, the power consumption of manganese zinc ferrite is required to be lower than 245kW/m ³ . In order to achieve this goal, some researchers usually add nanoscale auxiliary components to manganese zinc ferrite materials . Although nanoscale auxiliary components can reduce the power consumption of the material, there are disadvantages such as easy agglomeration and high cost of raw materials. Therefore, looking for a power manganese-zinc ferrite material with the lowest power consumption value at about 45°C and power consumption value lower than 245kW/m ³ and high saturation magnetic flux density without adding nanometer auxiliary components and its preparation method are very important for the expansion The application of manganese zinc ferrite in the field of digital equipment is of great significance.

Contents of the invention

The object of the present invention is to provide a manganese zinc ferrite material with high saturation magnetic flux density and low loss and a preparation method thereof.

Manganese zinc ferrite material with high saturation magnetic flux density and ultra-low power consumption at around 45°C, its main phase is spinel structure, and its main components are calculated in the form of oxides as follows:

_Fe2O3 : 52 _～ 54mol%;

MnO: 33～40mol%;

ZnO: 8～13mol%;

Auxiliary component CaCO ₃ : 100-600ppm;

SiO ₂ : 50-300ppm;

The rest are auxiliary components of metal oxides.

The metal oxide auxiliary component is A ₂ O ₃ , wherein A is a trivalent metal element, at least one of Co ³⁺ , Al ³⁺ , Bi ³⁺ is selected or added in combination, and the total amount is controlled at 100- 400ppm.

Or BO ₂ , where B is a tetravalent transition metal element, at least one or combined addition from Zr ⁴⁺ , Hf ⁴⁺ , Ti ⁴⁺ and Sn ⁴⁺ is added, and the total amount is controlled at 100-400ppm.

Or M ₂ O ₅ , wherein M is a pentavalent transition metal element, at least one of V ⁵⁺ and Nb ⁵⁺ is selected or added in combination, and the total amount is controlled at 100-400 ppm.

The content of metal oxide auxiliary components A ₂ O ₃ , BO ₂ and M ₂ O ₅ should meet the following formula: 0<X+Y+Z≤1000ppm, where X, Y and Z represent A ₂ O ₃ , BO ₂ and _{M2O5 content} .

The concrete steps of the preparation method of the manganese zinc ferrite material provided by the invention are:

1) Raw material mixing:

Select 52-54mol% Fe ₂ O ₃ , 33-40mol% MnO and 8-13mol% ZnO as raw materials, put them into a ball mill, add an equal weight of deionized water, ball mill for 2-5 hours, and the powder after mixing The average particle size of the material is controlled at 0.6-0.8μm, and the content of _SiO2 is controlled below 30ppm;

2) Pre-burning:

Dry the mixed and ground material, put it into the furnace for pre-burning, the pre-burning temperature is 800-950°C, and the pre-burning time is 2-4 hours;

3) Auxiliary ingredients added:

The added auxiliary components contain 100-600ppm CaCO ₃ and 50-300ppm SiO ₂ , and the weight ratio of CaCO ₃ and SiO ₂ added is 1.5-2.2:1; in addition to CaCO ₃ and SiO ₂ , A ₂ O ₃ is also selected , BO ₂ and M ₂ O ₅ are added as oxide auxiliary components, where in A ₂ O ₃ , A is a trivalent metal element, at least one of Co ³⁺ , Al ³⁺ , Bi ³⁺ is selected or added in combination , and its total amount is controlled at 100-400ppm; in BO ₂ , B is a tetravalent transition metal element, and at least one of Zr ⁴⁺ , Hf ⁴⁺ , Ti ⁴⁺ and Sn ⁴⁺ is selected or added together, and the total The amount is controlled at 100-400ppm; in M ₂ O ₅ , M is a pentavalent transition metal element, at least one of V ⁵⁺ and Nb ⁵⁺ is selected or added together, and the total amount is controlled at 100-400ppm, and three The sum of the amount of additives should be less than 1000ppm.

4) Secondary ball milling:

Put the material into a ball mill, add equal weight of deionized water, and ball mill for 3-6 hours, so that the average particle size of the calcined material is 1.0-1.2 μm;

5) Molding:

Dry the slurry, add 10wt% polyvinyl alcohol (PVA), and press to form;

6) Sintering:

Sintering is divided into three stages of heating, heat preservation and cooling.

Heating: From room temperature to sintering temperature 1250-1300°C, the heating rate is 3°C/min, and the heating process is carried out in the air.

Heat preservation: the sintering temperature is 1250-1300°C, the sintering time is 3-6 hours, the pressure in the sintering process is 1 atmosphere, the oxygen content is 3.0-5.0mol%, and the rest is N ₂ ,

Cooling: From the sintering temperature of 1250-1300°C to 200°C, the cooling rate is 2°C/min, and the air pressure is a standard atmospheric pressure. The oxygen content in the furnace during the cooling process should conform to the following formula: ${\log P}_{o_2}=a-b/T$ , where PO ₂ is the volume percentage of oxygen, a is a constant, its value is 4-5, b is a constant, its value is 14000-15000; T is the absolute temperature of the furnace.

The auxiliary components added to the manganese-zinc-ferrite material prepared by the present invention are all ordinary oxide particles, no need for nano-scale, and no agglomeration problem, so the addition is simple and the cost is low, and the material has a performance of less than 245kw at 45°C /m ³ power consumption, with a saturation flux density greater than 535mT at 25°C, so it is an excellent raw material that can be used to prepare the main transformer cores in switching power supplies in various digital products. The preparation method of the manganese-zinc ferrite material provided by the invention is simple, the pre-sintering and sintering temperature is low, the requirement for sintering equipment is low, and it can be realized in a common vacuum sintering furnace, so it is easy to realize industrialization.

Detailed ways

The invention provides a manganese-zinc ferrite material with high saturation magnetic flux density and ultra-low power consumption at about 45°C and a preparation method thereof. By adjusting the main formula, impurity addition and process parameters, the prepared MnZn ferrite material has a power consumption lower than 245kw/ ^m3 at 45°C and a saturation magnetic flux density greater than 535mT at 25°C.

There are spinel phases and a small amount of amorphous glass phases in the above-mentioned manganese zinc ferrite material which has a power consumption lower than 245kw/ ^m3 at 45°C and a saturation magnetic flux density greater than 535mT at 25°C, and The amorphous glass phase is uniformly distributed on the grain boundaries.

Select industrially pure Fe ₂ O ₃ , MnO and ZnO as raw materials. According to the molecular formula of the ingredients, various raw materials are weighed for mixing and grinding. The mixing and grinding equipment uses a high-energy planetary ball mill. During the mixing and grinding process, add equal weight of deionized water and ball mill for 2-5 hours. It is required that the average particle size of the powder after mixing and grinding should be controlled at 0.6-0.8 μm, and the content of _SiO2 should be controlled below 30ppm. The purpose of controlling the average particle size of the powder after mixing and grinding at 0.6-0.8 μm is to reduce the specific surface area of the powder, improve the reactivity of the powder, and make the powder completely spinelized at a lower pre-calcination temperature. And the content of SiO ₂ is controlled below 30ppm in order to control the total SiO ₂ content of the final product.

The temperature range during pre-firing is 800-950°C. After pre-firing, the raw materials are required to completely react to form a single spinel phase, and a lower pre-firing temperature is conducive to promoting the subsequent sintering reaction, which helps to reduce the sintering temperature. . A lot of research work has also shown that reducing the sintering temperature can effectively suppress the appearance of abnormal grains and reduce the porosity inside the grains, which plays a very important role in increasing the saturation magnetic flux density and reducing the power consumption of materials.

CaCO ₃ and SiO ₂ are selected as additives for joint addition in order to reduce the eddy current loss of manganese zinc ferrite. The loss of manganese zinc ferrite can be divided into three categories: hysteresis loss, eddy current loss and residual loss. Among them, power manganese zinc ferrite is generally dominated by hysteresis loss and eddy current loss under working conditions. Since CaCO ₃ and SiO ₂ can react, glass phase CaSiO ₃ is formed on the grain boundary, and glass phase CaSiO ₃ has a high resistivity, thereby increasing the resistance of the manganese zinc ferrite material and reducing the eddy current loss. In order to make CaCO ₃ and SiO ₂ react more completely, it is required that the weight percentage ratio of CaCO ₃ and SiO ₂ be controlled at 1.5-2.2:1. However, the addition of CaCO ₃ and SiO ₂ should not be too much, otherwise it will lead to adverse effects such as abnormal grain growth and excessive non-magnetic phases.

In addition to CaCO ₃ and SiO ₂ , A ₂ O ₃ , BO ₂ and M ₂ O ₅ are also selected as auxiliary components to add, where A is a trivalent metal element, at least selected from Co ³⁺ , Al ³⁺ , Bi ³⁺ One or combined addition; B is a tetravalent transition metal element, at least one of Zr ⁴⁺ , Hf ⁴⁺ , Ti ⁴⁺ and Sn ⁴⁺ is selected or added in combination; M is a pentavalent transition metal element, at least from V ⁵⁺ and Nb ⁵⁺ are selected or added together, and the sum of the three additions should be less than 1000ppm. The main purpose of the addition of these three ions is to adjust the ratio of Fe ²⁺ and Fe ³⁺ in the material. At the same time, high-valent ions can also form stable electron pairs with Fe ²⁺ to reduce the amount of Fe ²⁺ and Fe ³⁺ The electrons move between them, which increases the resistance of the ferrite material, thereby reducing the hysteresis loss and eddy current loss of the manganese zinc ferrite. However, the addition amount of the three ions must be controlled within 1000ppm, otherwise it will lead to adverse effects such as the output of the non-magnetic phase and the decomposition of the spinel phase.

The manganese-zinc ferrite material with a power consumption lower than 245kw/ ^m3 at 45°C and a saturation magnetic flux density greater than 535mT at 25°C and its preparation process are specifically described as follows:

1) Raw material mixing:

Select 52-54mol% Fe ₂ O ₃ , 33-40mol% MnO and 8-13mol% ZnO as raw materials, put them into a ball mill, add an equal weight of deionized water, ball mill for 2-5 hours, and the powder after mixing The average particle size of the material is controlled at 0.6-0.8μm, and the content of _SiO2 is controlled below 30ppm;

2) Pre-burning:

Dry the mixed and ground material, put it into the furnace for pre-burning, the pre-burning temperature is 800-950°C, and the pre-burning time is 2-4 hours:

3) Auxiliary ingredients added:

The added auxiliary components contain 100-600ppm CaCO ₃ and 50-300ppm SiO ₂ , and the weight ratio of CaCO ₃ and SiO ₂ added is 1.5-2.2:1; in addition to CaCO ₃ and SiO ₂ , A ₂ O ₃ is also selected , BO ₂ and M ₂ O ₅ are added as oxide auxiliary components, where in A ₂ O ₃ , A is a trivalent metal element, at least one of Co ³⁺ , Al ³⁺ , Bi ³⁺ is selected or added in combination , and its total amount is controlled at 100-400ppm; in BO ₂ , B is a tetravalent transition metal element, and at least one of Zr ⁴⁺ , Hf ⁴⁺ , Ti ⁴⁺ and Sn ⁴⁺ is selected or added together, and the total The amount is controlled at 100-400ppm; in M ₂ O ₅ , M is a pentavalent transition metal element, at least one of V ⁵⁺ and Nb ⁵⁺ is selected or added together, and the total amount is controlled at 100-400ppm, and three The sum of the amount of additives should be less than 1000ppm.

4) Secondary ball milling:

Put the material into a ball mill, add equal weight of deionized water, and ball mill for 3-6 hours, so that the average particle size of the calcined material is 1.0-1.2 μm;

5) Molding:

Dry the slurry, add 10wt% polyvinyl alcohol (PVA), and press to form;

6) Sintering:

Sintering is divided into three stages of heating, heat preservation and cooling.

Heating: From room temperature to sintering temperature 1250-1300°C, the heating rate is 3°C/min, and the heating process is carried out in the air.

Heat preservation: the sintering temperature is 1250-1300°C, the sintering time is 3-6 hours, the pressure in the sintering process is 1 atmosphere, the oxygen content is 3.0-5.0mol%, and the rest is N ₂ ,

Cooling: From the sintering temperature of 1250-1300°C to 200°C, the cooling rate is 2°C/min, and the air pressure is a standard atmospheric pressure. The oxygen content in the furnace during the cooling process should conform to the following formula: ${\log P}_{o_2}=a-b/T$ , where PO ₂ is the volume percentage of oxygen, a is a constant, its value is 4-5, b is a constant, its value is 14000-15000; T is the absolute temperature of the furnace.

The power manganese zinc ferrite material prepared by the method of the invention can have a power consumption lower than 245kw/ ^m3 at 45°C, and a saturation magnetic flux density greater than 535mT at 25°C. The preparation method provided by the invention has lower pre-sintering and sintering temperatures, and the added auxiliary components are ordinary particles, which greatly reduces the preparation cost and simplifies the preparation process. The manganese-zinc ferrite material with high saturation magnetic flux density and ultra-low power consumption at 45°C is an excellent raw material for preparing the main transformer core in switching power supplies in various digital products.

Example 1:

1) Raw material mixing:

Select 54mol% Fe ₂ O ₃ , 33mol% MnO and 13mol% ZnO as raw materials, put them into a ball mill, add an equal weight of deionized water, and ball mill for 2 hours. The average particle size of the mixed and milled powder is required to be controlled at 0.8 μm, the content of SiO ₂ is controlled at around 25ppm.

2) Pre-burning:

Dry the mixed and ground material, put it into the furnace for pre-burning, the pre-burning temperature is 950°C, and the pre-burning time is 3 hours.

3) Addition of impurities:

Add auxiliary ingredients to the pre-fired powder, these auxiliary ingredients include:

Table 1 serial number CaCO ₃ (ppm) SiO ₂ (ppm) Co ₂ O ₃ (ppm) Bi ₂ O ₃ (ppm) Al ₂ O ₃ (ppm) _ZrO2 (ppm) HfO ₂ (ppm) TiO ₂ (ppm) SnO ₂ (ppm) V ₂ O ₅ (ppm) Nb ₂ O ₅ (ppm) 1 100 50 200 100 100 100 100 100 100 100 100 2 600 300 100 0 0 100 0 0 0 200 200 3 600 300 400 0 0 100 0 0 100 0 100

4) Secondary ball milling:

Put the calcined material added with auxiliary components into a ball mill, add an equal weight of deionized water, and ball mill for 3 hours, so that the average particle size of the calcined material is 1.2 μm.

5) Molding:

Dry the slurry, add 10wt% polyvinyl alcohol (PVA), and press it into a ring shape with an outer diameter of 29.5 mm, an inner diameter of 12.2 mm and a height of 4.5 mm.

6) Sintering:

Sintering is divided into three stages of heating, heat preservation and cooling.

Heating: From room temperature to 1300°C sintering temperature, the heating rate is 3°C/min, and the heating process is carried out in the air.

Heat preservation: the sintering temperature is 1300°C, the sintering time is 3h, the pressure in the sintering process is 1 atmosphere, the oxygen content is 5mol%, and the rest is N ₂ .

Cooling: From the sintering temperature of 1300°C to 200°C, the cooling rate is 2°C/min, the air pressure is a standard atmospheric pressure, and the oxygen content in the furnace during the cooling process conforms to the following formula: ${\log P}_{o_2}=4-14000/T$ , where PO ₂ is the volume percentage of oxygen, and T is the absolute temperature of the furnace.

Use the SY-8232BH analyzer to measure the power consumption and saturation magnetic flux density of the sintered sample ring. The test results are shown in the table below:

Table 2: serial number 45°C power consumption (kW/m ³ ) test conditions: 100kHz, 200mT 25°C saturation magnetic flux density (mT) test conditions: 1194A/m, 50Hz 1 244 542 2 243 543 3 241 545

It can be seen from the measurement results that the prepared sample rings have an ultra-low power consumption value of 245kW/ ^m3 at 45°C, and the saturation magnetic flux density at 25°C is as high as 535mT or more, so these The material can well meet the performance requirements of household digital equipment for the magnetic core in the main transformer of the internal switching power supply.

Example 2:

1) Raw material mixing:

Select 52mol% Fe ₂ O ₃ , 40mol% MnO and 8mol% ZnO as raw materials, put them into a ball mill, add an equal weight of deionized water, and ball mill for 5 hours. The average particle size of the mixed and milled powder is required to be controlled at 0.6μm , the content of SiO ₂ is controlled at about 30ppm.

2) Pre-burning:

Dry the mixed and ground material, put it into the furnace for pre-burning, the pre-burning temperature is 800°C, and the pre-burning time is 3 hours.

3) Addition of impurities:

Add auxiliary ingredients to the pre-fired powder, these auxiliary ingredients include:

table 3: serial number CaCO ₃ (ppm) SiO ₂ (ppm) Co ₂ O ₃ (ppm) Bi ₂ O ₃ (ppm) Al ₂ O ₃ (ppm) _ZrO2 (ppm) HfO ₂ (ppm) TiO ₂ (ppm) SnO ₂ (ppm) V ₂ O ₅ (ppm) Nb ₂ O ₅ (ppm) 4 300 200 200 200 0 100 100 100 0 100 0 5 330 150 0 200 0 100 100 100 0 100 100 6 330 150 100 0 200 100 100 0 100 0 100

4) Secondary ball milling:

Put the calcined material with added auxiliary components into a ball mill, add an equal weight of deionized water, and ball mill for 6 hours, so that the average particle size of the calcined material is 1.0 μm.

5) Molding:

Dry the slurry, add 10wt% polyvinyl alcohol (PVA), and press it into a ring shape with an outer diameter of 29.5 mm, an inner diameter of 12.2 mm and a height of 4.5 mm.

6) Sintering:

Sintering is divided into three stages of heating, heat preservation and cooling.

Heating: From room temperature to sintering temperature of 1250°C, the heating rate is 3°C/min, and the heating process is carried out in the air.

Heat preservation: the sintering temperature is 1250°C, the sintering time is 6h, the pressure in the sintering process is 1 atmosphere, the oxygen content is 3.0mol%, and the rest is N ₂ .

Cooling: From the sintering temperature of 1250°C to 200°C, the cooling rate is 2°C/min, the air pressure is a standard atmospheric pressure, and the oxygen content in the furnace during the cooling process conforms to the following formula: ${\log P}_{o_2}=5-15000/T$ , where PO ₂ is the volume percentage of oxygen, and T is the absolute temperature of the furnace.

Use the SY-8232BH analyzer to measure the power consumption and saturation magnetic flux density of the sintered sample ring. The test results are shown in the table below:

Table 4: serial number 45°C power consumption (kW/m ³ ) test conditions: 100kHz, 200mT 25°C saturation magnetic flux density (mT) test conditions: 1194A/m, 50Hz 4 240 536 5 239 537 6 235 535

It can be seen from the measurement results that the prepared sample rings have an ultra-low power consumption value of 245kW/ ^m3 at 45°C, and the saturation magnetic flux density at 25°C is as high as 535mT or more, so these The material can well meet the performance requirements of household digital equipment for the magnetic core in the main transformer of the internal switching power supply.

Claims (7)

1. A high saturation magnetic flux density, ultra-low power manganese-zinc ferrite material, characterized in that, _Fe2O3 : 52 _～ 54mol%; MnO: 33～40mol%; ZnO: 8～13mol%; Auxiliary component CaCO ₃ : 100-600ppm; SiO ₂ : 50-300ppm; The rest are auxiliary components of metal oxides. 2. A high saturation magnetic flux density, ultra-low power manganese zinc ferrite material according to claim 1, characterized in that, the auxiliary component of the metal oxide is A ₂ O ₃ , wherein A is three Valence metal elements, at least one of Co ³⁺ , Al ³⁺ , and Bi ³⁺ is selected or added in combination, and the total amount is controlled at 100-400 ppm. 3. A kind of high saturation magnetic flux density, ultra-low power manganese zinc ferrite material according to claim 1, it is characterized in that, described metal oxide auxiliary component is BO ₂ , wherein B is a tetravalent transition Metal elements, at least one or combined addition from Zr ⁴⁺ , Hf ⁴⁺ , Ti ⁴⁺ and Sn ⁴⁺ , the total amount is controlled at 100-400ppm. 4. A kind of high saturation magnetic flux density, ultra-low power manganese zinc ferrite material according to claim 1, it is characterized in that, described metal oxide auxiliary component is M ₂ O ₅ , wherein M is five Valence transition metal elements, at least one of V ⁵⁺ and Nb ⁵⁺ is selected or added in combination, and the total amount is controlled at 100-400 ppm. 5. A high saturation magnetic flux density, ultra-low power manganese-zinc ferrite material according to claim 1, characterized in that the auxiliary components of the metal oxide are A ₂ O ₃ , BO ₂ and M ₂ The content of O ₅ should meet the following formula: 0<X+Y+Z≤1000ppm, where X, Y and Z represent the content of A ₂ O ₃ , BO ₂ and M ₂ O ₅ respectively. 6. a kind of preparation method of high saturation magnetic flux density as claimed in claim 1, ultra-low power manganese zinc ferrite material, it is characterized in that, the steps of method are: 1) Raw material mixing: Select 52-54mol% Fe ₂ O ₃ , 33-40mol% MnO and 8-13mol% ZnO as raw materials, put them into a ball mill, add an equal weight of deionized water, ball mill for 2-5 hours, and the powder after mixing The average particle size of the material is controlled at 0.6-0.8μm, and the content of _SiO2 is controlled below 30ppm; 2) Pre-burning: Dry the mixed and ground material, put it into the furnace for pre-burning, the pre-burning temperature is 800-950°C, and the pre-burning time is 2-4 hours; 3) Auxiliary ingredients added: The added auxiliary components contain 100-600ppm CaCO ₃ and 50-300ppm SiO ₂ , and the weight ratio of the added CaCO ₃ and SiO ₂ is 1.5-2.2:1; 4) Secondary ball milling: Put the material into a ball mill, add equal weight of deionized water, and ball mill for 3-6 hours, so that the average particle size of the calcined material is 1.0-1.2 μm; 5) Molding: Dry the slurry, add 10wt% polyvinyl alcohol, and press to form; 6) Sintering: Sintering is divided into three stages of heating, heat preservation and cooling. Heating: From room temperature to sintering temperature 1250-1300°C, the heating rate is 3°C/min, and the heating process is carried out in the air. Heat preservation: the sintering temperature is 1250-1300°C, the sintering time is 3-6 hours, the pressure in the sintering process is 1 atmosphere, the oxygen content is 3.0-5.0mol%, and the rest is N ₂ , Cooling: From the sintering temperature of 1250-1300°C to 200°C, the cooling rate is 2°C/min, and the air pressure is a standard atmospheric pressure. The oxygen content in the furnace during the cooling process should conform to the following formula: $\log P_{o_2}=a-b/T,$ Among them, PO ₂ is the volume percentage of oxygen, a is a constant, its value is 4-5, b is a constant, its value is 14000-15000; T is the absolute temperature of the furnace. 7. A kind of preparation method of high saturation magnetic flux density, ultra-low power consumption manganese zinc ferrite material according to claim 6, it is characterized in that, described step 3) auxiliary component is added: except CaCO ₃ and SiO ₂ In addition, A ₂ O ₃ , BO ₂ and M ₂ O ₅ are selected as oxide auxiliary components to add, wherein in A ₂ O ₃ , A is a trivalent metal element, at least from Co ³⁺ , Al ³⁺ , Bi ^{3 +} choose one or add together, and the total amount is controlled at 100-400ppm; in BO ₂ , B is a tetravalent transition metal element, at least selected from Zr ⁴⁺ , Hf ⁴⁺ , Ti ⁴⁺ and Sn ⁴⁺ One or combined addition, the total amount is controlled at 100-400ppm; in M ₂ O ₅ , M is a pentavalent transition metal element, at least one of V ⁵⁺ and Nb ⁵⁺ is selected or combined, and the total amount Control at 100-400ppm, and the sum of the three types of additions should be less than 1000ppm.