An ultra-low loss, high Bs, wide temperature and wide frequency manganese-zinc ferrite material and its preparation method

Abstract

The present invention discloses an ultra-low-loss, high-Bs, wide-temperature, wide-bandwidth manganese-zinc ferrite material and a preparation method thereof, specifically relating to the technical field of soft ferrite materials. The material comprises a main ingredient and auxiliary ingredients, wherein the main ingredients include, by mole percentage, Fe2O3 and ZnO, with the remainder being Mn3O4, and the auxiliary ingredients include CaO, SiO2, Nb2O5, Co2O3, TiO2, SnO2, ZrO2, V2O5, MoO3, and CuO. The present invention also provides a preparation method for the ferrite, which features low-melting-point material doping, low-temperature sintering, multi-stage pre-sintering, and rapid temperature rise. This method effectively increases the internal resistivity of the soft ferrite material, reduces eddy current loss in the magnetic core material during use, and increases the material's density, saturation magnetic induction intensity, and magnetic flux, resulting in a product with a higher sintering density and higher Bs characteristics.

Description

Technical Field

[0001] The present invention relates to the technical field of soft ferrite materials, and more particularly to an ultra-low loss, high Bs, wide temperature and wide frequency manganese-zinc ferrite material and a preparation method thereof. Background Art

[0002] Manganese zinc soft ferrite is a widely used magnetic material. Due to its mature preparation process and low price, it features high permeability, low power consumption, high saturation flux density (Bs), and relatively high resistivity, making it widely used in the electronics industry. For power manganese zinc ferrite, power consumption and Bs are two key characteristics. Low power consumption means lower losses during operation, resulting in higher conversion efficiency and lower heat generation. The rise of industries such as 5G and new energy vehicles has placed even higher demands on low power consumption for manganese zinc soft ferrite. First, the rise of 5G increases the frequency requirements for manganese zinc soft ferrite, requiring it to maintain low power consumption across a wider frequency range. Second, the operating environment of electronic devices in new energy vehicles is more demanding and covers a wide temperature range, so manganese zinc soft ferrite needs to operate within this wide temperature range. Furthermore, to meet the trend of miniaturization, high Bs characteristics are also crucial. From the working principle of the transformer, we can know that the output voltage V = KfBmAeN. When the output voltage is required to be constant, a higher Bs product can achieve a smaller effective cross-sectional area Ae of the magnetic core, which is conducive to the miniaturization of the product.

[0003] For power manganese zinc ferrite materials, low power loss has always been the goal pursued by manufacturers. For the current wide temperature and low power consumption ferrite materials, the current low power consumption manganese zinc ferrite materials can reduce the power consumption of 100KHz, 200mT to 280KW / m 3 It is very difficult to further improve this performance.

[0004] Improving the power consumption characteristics of manganese zinc soft ferrite mainly depends on its dense and uniform microstructure. If its density is low and its porosity is high, the number of magnetic domains per unit volume is small and it is prone to stress, making it difficult to improve its Bs. If its domain wall is thick, its resonant frequency is low and it is difficult to have good frequency characteristics. According to the Snock formula:

[0005]

[0006] The resonant frequency fr is inversely proportional to D. Therefore, reducing the domain wall width D can increase the domain wall resonant frequency fr. Under high-temperature operating conditions, losses primarily come from eddy current losses. Increasing resistivity can effectively reduce eddy current losses, maintaining a wide temperature range and achieving lower power consumption. Although the physical conditions influencing this are relatively clear, each condition easily influences each other, making it difficult to achieve a balance. Increasing the pre-sintering temperature and refining the grain size will improve frequency characteristics, but the material density and Bs will be difficult to increase. High pre-sintering temperatures will result in discontinuous grain growth during sintering, significantly reducing product performance. Increasing the sintering temperature promotes pore expulsion and grain growth, improving Bs and superposition characteristics. However, excessively high temperatures can cause abnormal ferrite grain growth, while certain metal ions volatilize, deoxidize, thermally dissociate, and react, causing the manganese-zinc soft ferrite to become brittle and its resistivity to decrease, making it difficult to achieve low high-frequency power consumption. Summary of the Invention

[0007] To address the technical problems existing in the prior art, the present invention provides a manganese-zinc ferrite material that exhibits ultra-low power consumption and high Bs over a wide frequency and temperature range. The present invention also provides a method for preparing the manganese-zinc ferrite material. Compared to traditional methods for preparing manganese-zinc ferrite, this method not only improves quality, production efficiency, and yield, but also exhibits significant microstructural and performance advantages.

[0008] The technical solution adopted in the present invention is as follows:

[0009] An ultra-low loss, high Bs, wide temperature and wide frequency manganese-zinc ferrite material comprises a main component and an auxiliary component, wherein the main component comprises 52-55.5 mol% Fe2O3, 7.5-11 mol% ZnO, and the remainder is Mn3O4 in molar percentage; the auxiliary components comprise CaO, SiO2, Nb2O5, Co2O3, TiO2, SnO2, ZrO2, V2O5, MoO3, and CuO.

[0010] In some embodiments of the present invention, the ultra-low loss, high Bs, wide temperature and wide frequency manganese-zinc ferrite material, based on the total weight of the main component, the auxiliary material components include: 0.03-0.2% CaO, 0.05-0.03% SiO2, 0.01-0.2% Nb2O5, 0.1-0.6% Co2O3, 0.05-0.2% TiO2, 0.05-0.3% SnO2, 0.01-0.2% ZrO2, 0.03-0.2% V2O5, 0.05-0.2% MoO3, 0.03-0.5% CuO.

[0011] In some embodiments of the present invention, the preparation method of the ultra-low loss, high Bs, wide temperature and broadband manganese-zinc ferrite material includes: weighing Fe2O3, ZnO and Mn3O4 according to the content of the main components, grinding and mixing, drying and pre-firing several times; weighing CaO, SiO2, Nb2O5, Co2O3, TiO2, SnO2, ZrO2, V2O5, MoO3, and CuO according to the content of the auxiliary components, adding them to the main components cooled after pre-firing, grinding and mixing, adding polyvinyl alcohol binder, spray granulation, making the spray granulated material into a blank, drying and sintering in an atmosphere-protected bell furnace to obtain an ultra-low loss, high Bs, wide temperature and broadband manganese-zinc ferrite material.

[0012] In some embodiments of the present invention, the method for preparing the ultra-low loss, high Bs, wide temperature and wide frequency manganese-zinc ferrite material comprises the following steps:

[0013] S1. Weigh Fe2O3, ZnO and Mn3O4 according to the content of the main components, grind and mix them, dry them and pre-calcine them two to three times;

[0014] S2. Weigh CaO, SiO2, Nb2O5, Co2O3, TiO2, SnO2, ZrO2, V2O5, MoO3, and CuO according to the content of the auxiliary components, add them to the main components after pre-calcination and cooling, and grind and mix them;

[0015] S3, adding polyvinyl alcohol binder to the material obtained in step S2, performing spray granulation, forming blanks from the spray granulated material and drying them;

[0016] S4. Sinter the dried blank at 1280-1330°C and, after cooling, obtain an ultra-low loss, high Bs, wide temperature and wide frequency manganese-zinc ferrite material.

[0017] In some embodiments of the present invention, in step S1, the temperature range of the multiple pre-firing is 840-940° C., and the pre-firing time is 0.5-3 hours.

[0018] In some embodiments of the present invention, in step S2, after grinding and mixing, the particle size of the material is 0.8 to 1.2 μm.

[0019] In some embodiments of the present invention, in step S3, the amount of polyvinyl alcohol binder added is 0.05-0.4%, that is, polyvinyl alcohol binder / material = 0.05-0.4%.

[0020] In some embodiments of the present invention, the specific sintering process in step S4 is:

[0021] S4-1: Raise the temperature to 200°C in an air atmosphere, and then slowly raise it to 300°C to completely volatilize the polyvinyl alcohol in the blank;

[0022] S4-2: Raise the temperature to 1100°C at a rate of 10-15°C / min, and reduce the oxygen content of the sintering atmosphere to 0.0-3.0%. Then directly raise the temperature to 1280-1330°C at a rate of 2-10°C / min, and reduce the oxygen content of the sintering atmosphere to 0.5-5.0%. Keep at this temperature for 150-300 minutes.

[0023] S4-3: After the insulation is completed, the temperature is lowered to 1000°C at a rate of 0.3-1.5°C / min, while gradually reducing the oxygen content. At 1100°C, the oxygen content is controlled at 0.5-1.0%, at 1050°C, the oxygen content of the atmosphere is controlled at 0.1-0.3%, and at 1000°C, the oxygen content is controlled at 0.02-0.05%;

[0024] S4-4: Cool down to 200°C at a rate of 3-10°C / min, while continuing to reduce the oxygen content. The oxygen content of the atmosphere at 1000-200°C is controlled below 50 ppm.

[0025] In some embodiments of the present invention, the grinding and mixing in step S1 or S2 is specifically sand milling or ball milling.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The preparation method of manganese-zinc ferrite provided by the present application adopts a low-temperature sintering method to avoid abnormal grain growth, and at the same time adds additives with low melting points, such as SiO2, VO2, Mo2O3, and CuO. These additives will form a liquid phase during the sintering process, promote the solid-phase reaction, fully eliminate the pores, and increase the density and saturation magnetic induction intensity of the material. At the same time, some high-valent ions enter the lattice (in the form of V 5+ For example), in order to satisfy the electrical neutrality, part of Fe 3+ Reduced to Fe 2+ , due to Fe 2+ It has a positive compensation effect on the ferrite magnetocrystalline anisotropy, improves the initial magnetic permeability of the material, and forms a stable V 5+ -Fe 2+ Ion pairs, reducing the electrons in Fe 3+ and Fe 2+ The jump between , thereby increasing the resistivity of the material prepared by the present application and greatly reducing the eddy current loss;

[0028] (2) The multi-stage pre-sintering method of the manganese-zinc ferrite preparation method provided in this application avoids the problem of high sintering temperature requirements and uneven pre-sintering reaction in a single pre-sintering. Through multi-stage pre-sintering, the main component material that has not reacted in advance is sintered multiple times, so that the powder undergoes a uniform ferritization reaction, which not only maintains the overall activity of the material but also avoids the risk of material cracking;

[0029] (3) The preparation method of manganese-zinc ferrite provided in the present application adopts a fast temperature rise sintering method. Since the densification time of the product in the temperature rise stage is short, the high temperature rise rate of the material will cause the product to quickly enter the high-temperature insulation stage. Therefore, the material components still maintain a high activity in the insulation stage, and the densification and grain growth of the material proceed at a faster rate. The grains grow uniformly, the density and saturation magnetic induction intensity of the material increase, and ultimately the product has a higher sintering density and higher Bs characteristics;

[0030] (4) The manganese zinc ferrite provided in this application can have the characteristics of high Bs and ultra-low loss in a wide temperature and frequency range, and has excellent industrial application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a grain photograph of the manganese-zinc ferrite material prepared in Example 1, with a magnification of 2000×;

[0032] Figure 2 This is a grain photograph of the manganese-zinc ferrite material prepared in Comparative Example 1, with a magnification of 2000×;

[0033] Figure 3 2 is a comparison diagram of the hysteresis loops of Example 1 and Comparative Example 1 (red: Example 1, black: Comparative Example 1);

[0034] Figure 4 2 is a comparison chart of volume loss between Example 1 and Comparative Example 1 (red: Example 1, black: Comparative Example 1). DETAILED DESCRIPTION

[0035] The present invention provides a method for preparing an ultra-low-loss, high-Bs, wide-temperature, and wide-band manganese-zinc ferrite material. Compared with traditional methods for preparing MnZn ferrite, this process not only has high quality, production efficiency, and qualified rate, but also has obvious advantages in microstructure and performance.

[0036] The invention uses industrial iron red Fe2O3, industrial manganese tetraoxide Mn3O4 and industrial ZnO as raw materials to prepare high-frequency and low-power consumption soft magnetic MnZn ferrite material.

[0037] The proportions of the above components are: Fe2O3: 52-55.5 mol%, ZnO: 7.5-11 mol%, and the balance is Mn3O4.

[0038] The auxiliary components are as follows in percentage by mass: CaO: 0.03-0.2%, SiO2: 0.05-0.03%, Nb2O5: 0.01-0.2%, Co2O3: 0.1-0.6%, TiO2: 0.05-0.2%, SnO2: 0.05-0.3%, ZrO2: 0.01-0.2%, V2O5: 0.03-0.2%, MoO3: 0.05-0.2%, CuO: 0.03-0.5%.

[0039] The method steps for preparing the above raw materials into manganese zinc ferrite material are as follows:

[0040] (1) According to the main formula, iron red Fe2O3, Mn3O4 and ZnO raw materials are accurately weighed, then placed in a sand mill, added with an appropriate amount of water to mix, and then dried.

[0041] (2) The mixed material is dried and then pre-fired in a muffle furnace at a temperature of 840-940°C for 0.5-3 hours. After cooling, it is pre-fired again using the same process as the first time. After sufficient cooling, the pre-fired material is returned to the sand mill. In this step, the auxiliary components are accurately weighed according to a predetermined ratio of their mass percentages (CaO: 0.03-0.2%, SiO2: 0.05-0.03%, Nb2O5: 0.01-0.2%, Co2O3: 0.1-0.6%, TiO2: 0.05-0.2%, SnO2: 0.05-0.3%, ZrO2: 0.01-0.2%, V2O5: 0.03-0.2%, MoO3: 0.05-0.2%, CuO: 0.03-0.5%), and are added to a sand mill together with an appropriate amount of water for sand milling for 1-3 hours, so that the D50 particle size of the sand abrasive is about 1.0 μm.

[0042] (3) Adding 0.05-0.4% by weight of polyvinyl alcohol (PVA) binder to the sanding slurry, and then spray granulating.

[0043] (4) The granulated ferrite material is pressed into a sample ring blank with an outer diameter of 25 mm, an inner diameter of 15 mm, and a height of 8 mm. The blank density is 3.0-3.15 kg / cm 3 .

[0044] (5) Sintering the pressed blank in an atmosphere-protected bell furnace. The sintering process is as follows:

[0045] (5.1) In air, heat the temperature at a rate of 2-5°C / min to 200°C, and then to 300°C at a rate of 0.5-1°C / min. The PVA added during the granulation process will decompose and volatilize at 200-300°C. If the temperature is raised too quickly during this stage, the PVA will volatilize violently, which may cause cracking of the blank. Therefore, the temperature should be raised slowly at 200-300°C to ensure that the PVA has sufficient time to volatilize.

[0046] (5.2) Raise the temperature to 1100°C at a rate of 10-15°C / min, reduce the oxygen content of the sintering atmosphere to 0.0-3.0%, then directly raise the temperature to 1280-1330°C at a rate of 2-10°C / min, reduce the oxygen content of the sintering atmosphere to 0.5-5.0%, and hold at this temperature for 150-300 minutes.

[0047] (5.3) After the holding period, the temperature is lowered to approximately 1000°C at a rate of 0.3-1.5°C / min. The oxygen content at 1100°C is controlled at approximately 0.5-1.0%, the oxygen content at 1050°C is controlled at 0.1-0.3%, and the oxygen content at 1000°C is controlled at 0.02-0.05%. During the holding period of sintering manganese-zinc ferrite, doped impurities such as Ca and Si are dissolved into the MnZn spinel. During the cooling period, these impurities migrate and segregate toward the grain boundaries. After cooling, a high-resistivity insulating layer is formed at the grain boundaries, thereby increasing the grain boundary resistivity and reducing the material's high-frequency power consumption characteristics. By slowly cooling the temperature between the holding period and the cooling period of 1000°C, impurities such as Ca and Si have sufficient time to migrate and segregate toward the grain boundaries, thereby increasing the thickness of the grain boundary layer and improving the material's high-frequency power consumption characteristics. Reducing the oxygen content of the sintering atmosphere at 1050°C and 1000°C is primarily to avoid the formation of heterogeneous structures during the holding period, which deteriorates the material's performance.

[0048] (5.4) Cool down to 200°C at a rate of 3-10°C / min, and control the oxygen content in the atmosphere to below 50 ppm.

[0049] The initial magnetic permeability of the manganese-zinc ferrite sample ring prepared according to the above process is 2900-3500, and the sintered density is 4.85-5.0kg / cm 3 , for specific related performance, please refer to the following specific embodiments.

[0050] The method of the present invention has the following characteristics:

[0051] 1. Use doping with low melting point materials and low temperature sintering: High temperature sintering is prone to abnormal growth of some active particles, affecting performance. Therefore, we use low temperature sintering to avoid abnormal grain growth. At the same time, low melting point additives such as SiO2, VO2, Mo2O3, CuO are added. These additives will form a liquid phase during the sintering process, promote the solid phase reaction, fully eliminate the pores, and increase the density and saturation magnetic induction intensity of the material; on the other hand, some high-valent ions enter the lattice (in the form of V 5+ For example), in order to satisfy the electrical neutrality, part of Fe 3+ Reduced to Fe 2+ , due to Fe 2+ It has a positive compensation effect on the ferrite magnetocrystalline anisotropy, improves the initial magnetic permeability of the material, and forms a stable V 5+ -Fe 2+ Ion pairs, reducing the electrons in Fe 3+ and Fe 2+ The jump between them increases the resistivity of the material and reduces the eddy current loss.

[0052] Second, pre-sinter the main raw materials in multiple stages: Single pre-sintering requires a high sintering temperature and uneven pre-sintering reaction. Through multi-stage pre-sintering, the unreacted materials are sintered multiple times, so that the powder undergoes a uniform ferritization reaction, maintaining the overall activity of the material and avoiding the risk of cracking.

[0053] 3. Fast heating in the sintering stage: The high heating rate will make the product enter the high-temperature insulation stage quickly. Since the densification time of the product in the heating stage is short, the material still maintains a high activity in the insulation stage. Therefore, the densification and grain growth proceed at a faster rate in the insulation stage, the grains grow evenly, and the density, saturation magnetic induction intensity and magnetism of the material increase, so that the product has a higher sintering density and higher Bs characteristics.

[0054] Example 1:

[0055] (1) According to the main formula, 52 mol% Fe2O3, 7.5 mol% ZnO, and the balance Mn3O4 were accurately weighed, and then placed in a sand mill, and an appropriate amount of water was added to mix, and then dried.

[0056] (2) The mixed material is first dried and then placed in a muffle furnace for pre-calcination at a temperature of 840°C for 3 hours. After cooling, it is pre-calcined again using the same pre-calcination process as the first time. After sufficient cooling, the pre-calcined material is returned to the sand mill. In this step, the auxiliary components are accurately weighed according to the predetermined proportions of their mass percentages (0.05% CaO, 0.05% SiO2, 0.01% Nb2O5, 0.5% Co2O3, 0.2% TiO2, 0.3% SnO2, 0.05% ZrO2, 0.1% V2O5, 0.1% MoO3, 0.1% CuO) and added to the sand mill together with an appropriate amount of water for sand milling for 2 hours, so that the D50 particle size of the sand mill is approximately 1.0 μm.

[0057] (3) Add 0.05% by weight of polyvinyl alcohol (PVA) binder to the sanding slurry, and then perform spray granulation.

[0058] (4) The granulated ferrite material is pressed into a sample ring blank with an outer diameter of 25 mm, an inner diameter of 15 mm, and a height of 8 mm. The blank density is 3.0-3.15 kg / cm 3 .

[0059] (5) Sintering the pressed blank in an atmosphere-protected bell furnace.

[0060] The specific sintering process is as follows:

[0061] (5.1) In air, increase the temperature at a rate of 2°C / min to 200°C, and then increase the temperature at a rate of 0.5°C / min to 300°C.

[0062] (5.2) Raise the temperature to 1100°C at a rate of 10°C / min, reducing the oxygen content of the sintering atmosphere to 0.05%. Then directly raise the temperature to 1300°C at a rate of 5°C / min, reducing the oxygen content of the sintering atmosphere to 3%, and hold at this temperature for 300 minutes.

[0063] (5.3) After the insulation is completed, the temperature is reduced to about 1000℃ at a rate of 1℃ / min. The oxygen content at 1100℃ is controlled at about 1.0%, the oxygen content at 1050℃ is controlled at 0.2%, and the oxygen content at 1000℃ is controlled at 0.05%.

[0064] (5.4) Cool down to 200°C at a rate of 10°C / min, and control the oxygen content in the atmosphere to below 50 ppm.

[0065] The grain size of the manganese-zinc ferrite material prepared in this embodiment was measured by Quantum SEM3200 and Japanese Iwasaki SY8218 soft magnetic properties analyzer. Figure 1 As shown, the volume loss and magnetic induction intensity are as follows Figure 3-4The other related performances are shown in the following table:

[0066]

[0067] Example 2:

[0068] (1) According to the main formula, 55.5 mol% Fe2O3, 9.2 mol% ZnO, and the balance Mn3O4 were accurately weighed, and then placed in a sand mill, and an appropriate amount of water was added to mix, and then dried.

[0069] (2) The mixed material is first dried and then placed in a muffle furnace for pre-calcination at a temperature range of 840-940°C for a period of 0.5-3 hours. After cooling, it is pre-calcined again using the same pre-calcination process as the first time. After sufficient cooling, the pre-calcined material is returned to the sand mill. In this step, the auxiliary components are accurately weighed according to the predetermined proportions of their mass percentages (0.07% CaO, 0.06% SiO2, 0.03% Nb2O5, 0.6% Co2O3, 0.1% TiO2, 0.4% SnO2, 0.2% ZrO2, 0.15% V2O5, 0.2% MoO3, 0.3% CuO) and added to the sand mill along with an appropriate amount of water for sand milling for 1-3 hours, resulting in a D50 particle size of the sand mill of approximately 1.0 μm.

[0070] (3) Add 0.08% by weight of polyvinyl alcohol (PVA) binder to the sanding slurry, and then perform spray granulation.

[0071] (4) The granulated ferrite material is pressed into a sample ring blank with an outer diameter of 25 mm, an inner diameter of 15 mm, and a height of 8 mm. The blank density is 3.0-3.15 kg / cm 3 .

[0072] (5) Sintering the pressed blank in an atmosphere-protected bell furnace.

[0073] The specific sintering process is as follows:

[0074] (5.1) In air, increase the temperature at a rate of 2°C / min to 200°C, and then increase the temperature at a rate of 1°C / min to 300°C.

[0075] (5.2) Raise the temperature to 1100°C at a rate of 10°C / min, reducing the oxygen content of the sintering atmosphere to 0.05%. Then directly raise the temperature to 1300°C at a rate of 5°C / min, reducing the oxygen content of the sintering atmosphere to 3%, and hold at this temperature for 300 minutes.

[0076] (5.3) After the insulation is completed, the temperature is reduced to about 1000℃ at a rate of 1℃ / min. The oxygen content at 1100℃ is controlled at about 1.0%, the oxygen content at 1050℃ is controlled at 0.2%, and the oxygen content at 1000℃ is controlled at 0.05%.

[0077] (5.4) Cool down to 200°C at a rate of 10°C / min, and control the oxygen content in the atmosphere to below 50 ppm.

[0078] After testing and analysis by a Japanese Iwasaki SY8218 soft magnetic properties analyzer, the relevant properties of the manganese-zinc ferrite material prepared in this embodiment are shown in the following table:

[0079]

[0080] Comparative Example 1

[0081] (1) According to the main formula, 55.5 mol% Fe2O3, 11 mol% ZnO, and the balance Mn3O4 were accurately weighed, and then placed in a sand mill, and an appropriate amount of water was added to mix, and then dried.

[0082] (2) The mixed material is dried and then pre-fired in a muffle furnace at a temperature of 840-940°C for 1 hour. After sufficient cooling, the pre-fired material is returned to the sand mill. In this step, the auxiliary components are accurately weighed according to the predetermined proportions of their mass percentages (0.05% CaO, 0.05% SiO2, 0.01% Nb2O5, 0.5% Co2O3, 0.2% TiO2, 0.3% SnO2, and 0.05% ZrO2) and added to the sand mill along with an appropriate amount of water. The sand mill is then sanded for 1-3 hours to a D50 particle size of approximately 1.0 μm.

[0083] (3) Add 0.4% by weight of polyvinyl alcohol (PVA) binder to the sanding slurry, and then perform spray granulation.

[0084] (4) The granulated ferrite material is pressed into a sample ring blank with an outer diameter of 25 mm, an inner diameter of 15 mm, and a height of 8 mm. The blank density is 3.0-3.15 kg / cm 3 .

[0085] (5) Sintering the pressed blank in an atmosphere-protected bell furnace.

[0086] The specific sintering process is as follows:

[0087] (5.1) In air, increase the temperature at a rate of 2°C / min to 200°C, and then increase the temperature at a rate of 1°C / min to 300°C.

[0088] (5.2) Raise the temperature to 1100°C at a rate of 3°C / min, reducing the oxygen content of the sintering atmosphere to 0.05%. Then directly raise the temperature to 1330°C at a rate of 5°C / min, reducing the oxygen content of the sintering atmosphere to 4%, and hold at this temperature for 300 minutes.

[0089] (5.3) After the insulation is completed, the temperature is reduced to about 1000℃ at a rate of 1℃ / min. The oxygen content at 1100℃ is controlled at about 0.5%, the oxygen content at 1050℃ is controlled at 0.3%, and the oxygen content at 1000℃ is controlled at 0.02%.

[0090] (5.4) Cool down to 200°C at a rate of 5°C / min, and control the oxygen content in the atmosphere below 50 ppm.

[0091] The grain size of the manganese-zinc ferrite material prepared in this embodiment was measured by Quantum SEM3200 and Japanese Iwasaki SY8218 soft magnetic properties analyzer. Figure 2 As shown, the volume loss and magnetic induction intensity are as follows Figure 3-4 The other related performances are shown in the following table:

[0092]

[0093]

Claims

1. An ultra-low loss, high Bs, wide temperature and wide frequency manganese-zinc ferrite material, characterized in that: The invention comprises a main component and an auxiliary component, wherein the main component comprises 52-55.5 mol% Fe2O3, 7.5-11 mol% ZnO, and the balance Mn3O4 by molar percentage; based on the total weight of the main component, the auxiliary component comprises: 0.03-0.2% CaO, 0.03-0.05% SiO2, 0.01-0.2% Nb2O5, 0.1-0.6% Co2O3, 0.05-0.2% TiO2, 0.05-0.3% SnO2, 0.01-0.2% ZrO2, 0.03-0.2% V2O5, 0.05-0.2% MoO3, and 0.03-0.5% CuO; the ultra-low loss, high Bs, wide temperature and wide frequency manganese-zinc ferrite material is prepared by the following steps: S1. Weigh Fe2O3, ZnO and Mn3O4 according to the content of the main components, grind and mix them, dry them and pre-calculate them twice; the temperature range of the two pre-calcinations is 840-940℃, and the pre-calcination time is 0.5-3 hours; S2. Weigh CaO, SiO2, Nb2O5, Co2O3, TiO2, SnO2, ZrO2, V2O5, MoO3, and CuO according to the content of the auxiliary components, add them to the main components after pre-calcination and cooling, and grind and mix them; after grinding and mixing, the material particle size should be 0.8-1.2μm; S3, adding polyvinyl alcohol binder to the material obtained in step S2, spray granulating, forming the spray granulated material into blanks and drying; the weight ratio of the polyvinyl alcohol binder added is 0.05-0.4%; S4, sintering the dried blank at 1280-1330° C. and cooling it to obtain an ultra-low loss, high Bs, wide temperature and wide frequency manganese-zinc ferrite material; The specific sintering process in step S4 is as follows: S4-1: Raise the temperature to 200°C in an air atmosphere, and then slowly raise it to 300°C to completely volatilize the polyvinyl alcohol in the blank; S4-2: Raise the temperature to 1100°C at a rate of 10-15°C / min, reduce the oxygen content of the sintering atmosphere to 0.0-3.0%, then directly raise the temperature to 1280-1330°C at a rate of 2-10°C / min, reduce the oxygen content of the sintering atmosphere to 0.5-5.0%, and keep warm for 150-300 minutes; S4-3: After the insulation is completed, the temperature is lowered to 1000°C at a rate of 0.3-1.5°C / min, and the oxygen content is gradually reduced to 0.02-0.05%; S4-4: Cool down to 200°C at a rate of 3-10°C / min, and control the oxygen content in the atmosphere below 50 ppm.

2. The ultra-low loss, high Bs, wide temperature and wide frequency manganese-zinc ferrite material according to claim 1, characterized in that: The grinding and mixing in step S1 or S2 is specifically sand milling or ball milling.

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