A manganese-zinc ferrite material and its preparation method

Abstract

This invention provides a manganese-zinc ferrite material and its preparation method, belonging to the technical field of electronic component materials. This invention achieves small and dense grains by controlling grain size through low-temperature sintering and using CuO as the main flux to promote porosity removal and increase density, thereby reducing power consumption at medium and high frequencies. Compared with existing technologies, this invention can reduce power consumption by approximately 10% at 300kHz and approximately 30% at 500kHz.

Description

Technical Field

[0001] This invention belongs to the field of electronic component materials technology, specifically relating to a manganese-zinc ferrite material and its preparation method. Background Technology

[0002] For power manganese-zinc ferrite materials, low power loss is the most important performance characteristic for manufacturers. Traditional ferrite materials are widely used in low-frequency inductors and transformers. However, with the development of third-generation semiconductor technologies such as SiC and GaN, the frequency and conversion efficiency of power devices are gradually improving. Traditional materials typically operate at frequencies around 100kHz, with a few devices requiring higher frequencies, mainly divided into mid-high frequency (300kHz–1MHz) and ultra-high frequency (1MHz–3MHz). However, with advancements in the semiconductor industry, the conventional 100kHz requirement can no longer meet miniaturization needs, and the frequency is gradually increasing to 300kHz–1MHz. Currently, 300kHz–1MHz is not only common in DC-DC converters but is also increasingly being used in AC-DC converters, wireless charging, inverters, and motor drives. Therefore, the demand for soft magnetic ferrites in this frequency band is growing rapidly.

[0003] Power consumption is mainly divided into hysteresis loss, eddy current loss, and residual loss. Improving power consumption characteristics in the mid-to-high frequency range (300kHz to 1MHz) primarily involves reducing eddy current loss while maintaining hysteresis loss. From the eddy current formula, we know that:

[0004]

[0005] In the formula, d represents the thickness of the sheet-like magnetic core material, which for ferrite materials is the grain size. ρ represents the resistivity. It is evident that larger grain sizes result in greater eddy current losses, while higher resistivity leads to lower eddy current losses. Therefore, to reduce eddy current losses in ferrites, it is necessary to reduce the grain size while simultaneously increasing the resistivity. Furthermore, eddy current losses at mid-to-high frequencies (300kHz–1MHz) differ somewhat from those at low frequencies. Due to the higher frequencies, eddy currents may penetrate multiple grains, forming transgranular eddy currents, further increasing power consumption. The reason for eddy currents penetrating grains is generally considered to be the electromagnetic discontinuity of grain orientation and boundaries. Therefore, while reducing grain size, it is also necessary to pay attention to grain consistency. In the sintering of soft magnetic ferrites, reducing grain size is often achieved by lowering the sintering temperature. However, the inhomogeneity of the grains leads to inconsistent grain growth at lower sintering temperatures, resulting in increased transgranular eddy currents and failing to effectively reduce power consumption. Furthermore, the reduced density at lower sintering temperatures also deteriorates the overall magnetic properties of the core. Therefore, simply lowering the sintering temperature does not reduce power consumption. In soft magnetic ferrite materials, resistivity is generally improved by doping with Si, Ca, etc., but the uneven distribution of these dopants at grain boundaries also leads to increased transgranular eddy currents, ultimately resulting in increased high-frequency power consumption. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a manganese zinc ferrite material and its preparation method. The manganese zinc ferrite material provided by this invention has low power consumption in the mid-to-high frequency range.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] This invention provides a manganese-zinc ferrite material, the raw materials for which preparation includes main components and auxiliary components;

[0009] Based on the total molar amount of the main components being 100%, the main components include: Fe2O3 52-55.5 mol%, ZnO2 5.5-9.5 mol%, CuO 0.1-0.5 mol%, and the balance being Mn3O4;

[0010] The auxiliary components, based on their percentage of the total mass of the main components, include: CaO 0.03–0.2%, SiO₂ 0.005–0.03%, 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%, and HfO₂ 0.05–0.2%; the density of the manganese-zinc ferrite material is 4.85–5.0 g / cm³. 3 .

[0011] Preferably, the initial magnetic permeability of the manganese-zinc ferrite material is 2900 to 3500.

[0012] This invention provides a method for preparing the manganese-zinc ferrite material described above, comprising the following steps:

[0013] The main component is milled to obtain abrasive.

[0014] The abrasive is pre-fired to obtain pre-fired material;

[0015] The pre-burned material and the auxiliary components are mixed and milled to obtain a mixed abrasive.

[0016] The mixed abrasive and binder are mixed and molded to obtain a blank;

[0017] The blank is sintered to obtain the manganese-zinc ferrite material; the sintering temperature is 1150-1250℃.

[0018] Preferably, the sintering process includes:

[0019] In air, the temperature is increased to 200°C at a rate of 2–5°C / min, and then increased to 300°C at a rate of 0.5–1°C / min.

[0020] The temperature is increased to 1100℃ at a heating rate of 0.5–3℃ / min, while the oxygen content of the sintering atmosphere at 1100℃ is 0.0–3.0%. Then the temperature is increased to 1150–1250℃ at a heating rate of 2–10℃ / min, while the oxygen content of the sintering atmosphere at 1150–1250℃ is 0.5–5.0%. The holding time at 1150–1250℃ is 150–300 min.

[0021] The temperature is lowered to 1000℃ at a cooling rate of 0.3–1.5℃ / min. During the cooling process to 1000℃, the oxygen content of the sintering atmosphere at 1100℃ is 0.5–1.0%, the oxygen content of the sintering atmosphere at 1050℃ is 0.1–0.3%, and the oxygen content of the sintering atmosphere at 1000℃ is 0.02–0.05%.

[0022] The temperature is lowered to 200℃ at a rate of 3–10℃ / min, while the oxygen content of the sintering atmosphere at 200℃ is ≤50ppm.

[0023] Preferably, the preheating temperature is 840–940°C, and the holding time is 0.5–3 hours.

[0024] Preferably, the D50 particle size of the mixed abrasive is 1.0 μm.

[0025] Preferably, the adhesive comprises an aqueous solution of polyvinyl alcohol.

[0026] Preferably, the blank is a ring-shaped blank.

[0027] Preferably, the density of the blank is 3.0–3.15 g / cm³. 3 .

[0028] Preferably, the main component is milled at a speed of 270 r / min for a time of 30 to 60 min.

[0029] This invention provides a manganese-zinc ferrite material, the raw materials of which include a main component and auxiliary components; based on the total molar amount of the main component as 100%, the main component includes: Fe2O3 52-55.5 mol%, ZnO2 5.5-9.5%, CuO 0.1-0.5%, and the balance being Mn3O4; based on the percentage of the total mass of the main component, the auxiliary components include: CaO The composition of the manganese-zinc ferrite material is as follows: 0.03–0.2%, SiO₂ 0.005–0.03%, 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%, HfO₂ 0.05–0.2%; the density of the manganese-zinc ferrite material is 4.85–5.0 g / cm³. 3 The invention incorporates CuO into the main formulation to form a quaternary composition: To reduce mid-to-high frequency power consumption, it is necessary to reduce the grain size and compensate for the increased hysteresis loss caused by the reduction in grain size in other ways. This invention controls the grain size through low-temperature sintering and uses CuO as the fluxing agent in the main formulation to promote the expulsion of pores and increase density, thereby achieving small and dense grains and reducing mid-to-high frequency power consumption. Compared with existing technologies, this invention can reduce power consumption by approximately 10% at 300kHz and approximately 30% at 500kHz.

[0030] This invention provides a method for preparing the manganese-zinc ferrite material described above. In manganese-zinc ferrite, the conventional sintering temperature is around 1300–1400℃. However, reducing mid-to-high frequency power consumption requires further temperature reduction, which can decrease grain size and thus reduce eddy current losses. Therefore, this invention uses an ultra-low sintering temperature (1150–1250℃), combined with the addition of flux CuO to form a quaternary main formulation, resulting in a low-temperature sintered dense grain structure, reducing mid-to-high frequency power consumption, and exhibiting good grain boundary uniformity. Increasing the cooling time: During the sintering and holding stage of MnZn ferrite, doped impurities such as Ca and Si dissolve into the MnZn spinel. During the cooling stage, these impurities migrate and segregate towards the grain boundaries, forming a high-resistivity insulating layer at the grain boundaries after cooling, thereby increasing grain boundary resistance, reducing the high-frequency power consumption characteristics of the material, and improving grain boundary uniformity. Extending the densification time during sintering: Short densification times result in incomplete crystal structures in the initially formed compounds, containing numerous defects and pores. At higher frequencies, eddy currents may penetrate these defects and pores, forming transgranular eddy currents and increasing power consumption. Therefore, reducing power consumption at mid-to-high frequencies requires extending the densification time (sintering temperature range of 300–1100℃). During densification, reducing the oxygen content gradually expels pores, resulting in a dense, uniformly sized ferrite core. Furthermore, this invention promotes uniform grain growth through low-temperature sintering and extended densification time.

[0031] The method provided by this invention reduces the power consumption of manganese-zinc ferrite materials in the mid-to-high frequency band. With the development of emerging technologies such as artificial intelligence, the Internet of Things, and 5G communication, the demand for this material will increase, promoting the development of related industries. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 The image shows a SEM image of the manganese-zinc ferrite material obtained in Example 1.

[0034] Figure 2 The image shows the SEM image of the manganese-zinc ferrite material obtained in Comparative Example 1. Detailed Implementation

[0035] This invention provides a manganese-zinc ferrite material, the raw materials for which preparation includes a main component and auxiliary components; based on the total molar amount of the main component as 100%, the main component includes: Fe2O3 52-55.5 mol%, ZnO2 5.5-9.5 mol%, CuO 0.1-0.5 mol%, and the balance is Mn3O4;

[0036] The auxiliary components, based on their percentage of the total mass of the main components, include: CaO 0.03–0.2%, SiO2 0.005–0.03%, 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%, and HfO2 0.05–0.2%.

[0037] Based on the total molar amount of the main component being 100%, the main component in the raw materials for preparing the manganese-zinc ferrite material provided by the present invention includes 52-55.5 mol% Fe2O3. In the embodiments of the present invention, it can specifically be 52 mol%, 52.1 mol%, 53 mol%, 54 mol%, 55 mol%, or 55.5 mol%.

[0038] Based on the total molar amount of the main component being 100%, the main component in the raw materials for preparing the manganese-zinc ferrite material provided by the present invention includes 5.5 to 9.5 mol% ZnO2. In the embodiments of the present invention, it can specifically be 5.5 mol%, 6.0 mol%, 6.5 mol%, 7.0 mol%, 7.5 mol%, 8.0 mol%, 9.0 mol%, or 9.5 mol%.

[0039] Based on the total molar amount of the main component being 100%, the main component in the raw materials for preparing the manganese-zinc ferrite material provided by the present invention includes 0.1 to 0.5 mol% CuO. In the embodiments of the present invention, it can specifically be 0.1 mol%, 0.2 mol%, 0.3 mol%, 0.4 mol%, or 0.5 mol%.

[0040] Based on the total molar amount of the main component being 100%, the main component in the raw materials for preparing the manganese-zinc ferrite material provided by the present invention includes the balance Mn3O4.

[0041] The auxiliary components in the raw materials for preparing the manganese-zinc ferrite material provided by the present invention include 0.03 to 0.2% CaO, based on the percentage of the total mass of the main components. In the embodiments of the present invention, the specific percentages may be 0.03%, 0.05%, 0.1%, 0.15%, or 0.2%.

[0042] The auxiliary components in the raw materials for preparing the manganese-zinc ferrite material provided by the present invention include 0.005% to 0.03% SiO2, based on the percentage of the total mass of the main components. In the embodiments of the present invention, the specific percentage can be 0.005%, 0.01%, 0.02%, or 0.03%.

[0043] The auxiliary components in the raw materials for preparing the manganese-zinc ferrite material provided by the present invention include 0.01 to 0.2% Nb2O5 as a percentage of the total mass of the main components. In the embodiments of the present invention, the specific percentages may be 0.01%, 0.03%, 0.05%, 0.1%, 0.15%, or 0.2%.

[0044] The auxiliary components in the raw materials for preparing the manganese-zinc ferrite material provided by the present invention include 0.1% to 0.6% Co2O3 as a percentage of the total mass of the main components. In the embodiments of the present invention, the specific percentages may be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or 0.6%.

[0045] The auxiliary components in the raw materials for preparing the manganese-zinc ferrite material provided by the present invention include 0.05-0.2% TiO2, based on the percentage of the total mass of the main components. In the embodiments of the present invention, the specific percentages may be 0.05%, 0.08%, 0.1%, 0.15%, or 0.2%.

[0046] The auxiliary components in the raw materials for preparing the manganese-zinc ferrite material provided by the present invention include 0.05-0.3% SnO2, based on the percentage of the total mass of the main components. In the embodiments of the present invention, the specific percentages may be 0.05%, 0.08%, 0.1%, 0.15%, 0.2%, 0.25%, or 0.3%.

[0047] The auxiliary components in the raw materials for preparing the manganese-zinc ferrite material provided by the present invention include 0.01 to 0.2% ZrO2, based on the percentage of the total mass of the main components. In the embodiments of the present invention, the specific percentages may be 0.01%, 0.04%, 0.1%, 0.12%, 0.14%, 0.16%, or 0.2%.

[0048] The auxiliary components in the raw materials for preparing the manganese-zinc ferrite material provided by the present invention include 0.03 to 0.2% V2O5 as a percentage of the total mass of the main components. In the embodiments of the present invention, the specific percentages can be 0.03%, 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, or 0.2%.

[0049] The auxiliary components in the raw materials for preparing the manganese-zinc ferrite material provided by the present invention include 0.05-0.2% MoO3 as a percentage of the total mass of the main components. In the embodiments of the present invention, the specific percentages may be 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, or 0.2%.

[0050] The auxiliary components in the raw materials for preparing the manganese-zinc ferrite material provided by the present invention include 0.05-0.2% HfO2 as a percentage of the total mass of the main components. In the embodiments of the present invention, the specific percentages can be 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, or 0.2%.

[0051] In this invention, the initial magnetic permeability of the manganese-zinc ferrite material is preferably 2900–3500, and in specific embodiments of this invention, it can be 2900, 3000, 3002, 3050, 3063, 3100, 3200, 3205, 3300, 3400, or 3500; the density is 4.85–5.0 g / cm³. 3 In specific embodiments of the present invention, it can be 4.85 g / cm³. 3 4.90 g / cm 3 4.92g / cm 3 4.94 g / cm 3 4.97g / cm 3 Or 4.98g / cm 3 .

[0052] In this invention, the grain size of the manganese zinc ferrite material is preferably 10-13 μm.

[0053] Doping CuO into the main formulation to form a quaternary formulation: To reduce mid-to-high frequency power consumption, it is necessary to reduce the grain size and compensate for the increased hysteresis loss caused by the reduction in grain size in other ways. This invention controls the grain size by using low-temperature sintering and uses CuO as the fluxing agent in the main formulation to promote the expulsion of pores and increase density, thereby achieving the characteristics of small grains and dense grain structure, reducing mid-to-high frequency power consumption. Compared with the prior art, this invention can reduce power consumption by about 10% at 300kHz and about 30% at 500kHz.

[0054] This invention provides a method for preparing the manganese-zinc ferrite material described above, comprising the following steps:

[0055] The main component is milled to obtain abrasive.

[0056] The abrasive is pre-fired to obtain pre-fired material;

[0057] The pre-burned material and the auxiliary components are mixed and milled to obtain a mixed abrasive.

[0058] The mixed abrasive and binder are mixed and molded to obtain a blank;

[0059] The blank is sintered to obtain the manganese-zinc ferrite material.

[0060] Unless otherwise specified, all raw materials and equipment used in this invention are commercially available products.

[0061] The present invention involves grinding the main components to obtain abrasive.

[0062] In this invention, the solvent used for milling the main component preferably includes water; the mass ratio of water to the main component is preferably 1:1.

[0063] In this invention, the preferred rotation speed for milling the main component is 270 r / min; the preferred milling time for the main component is 30 to 60 min, and in specific embodiments of this invention, it can be 30 min, 40 min, 50 min, or 60 min.

[0064] After the sand milling is completed, the present invention preferably includes drying and grinding the obtained sand mill slurry, and then passing it through a 100-mesh sieve to obtain the sand mill material.

[0065] After obtaining the abrasive, the present invention pre-fires the abrasive to obtain pre-fired material.

[0066] In this invention, the pre-firing temperature is preferably 840-940°C, and in specific embodiments of this invention, it can be 840°C, 850°C, 860°C, 880°C, 900°C, 920°C, or 940°C; the pre-firing holding time is preferably 0.5-3 hours, and in specific embodiments of this invention, it can be 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, or 3 hours.

[0067] After the pre-firing is completed, the present invention preferably further includes cooling the resulting material.

[0068] After obtaining the pre-burned material, the present invention mixes and mills the pre-burned material and the auxiliary components to obtain mixed abrasive.

[0069] In this invention, the solvent for the mixed sand milling preferably includes water; the mass ratio of the water to the total mass of the pre-calcined material and auxiliary components is preferably 1:1. In this invention, the rotation speed of the mixed sand milling is preferably 270 r / min; the mixing and sand milling time is preferably 1 to 3 hours, and in the embodiments of this invention, it can specifically be 1 hour, 2 hours, or 3 hours.

[0070] After the mixed sand milling is completed, the present invention preferably dries the obtained mixed sand milling slurry to obtain mixed sand milling material.

[0071] In this invention, the D50 particle size of the mixed abrasive is preferably 1.0 μm.

[0072] After obtaining the mixed abrasive, the present invention mixes the mixed abrasive with a binder and shapes it to obtain a blank.

[0073] In this invention, the molding preferably includes granulation and pressing; the granulation preferably includes spray granulation.

[0074] In this invention, the binder preferably comprises an aqueous solution of polyvinyl alcohol (PVA); the mass concentration of the aqueous solution of polyvinyl alcohol is preferably 0.05-0.4%, and in the embodiments of this invention, it can specifically be 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, or 0.4%; the mass of the binder is preferably 20% of the mass of the mixed abrasive sand.

[0075] In this invention, the blank is preferably a ring-shaped blank; the outer diameter of the blank is preferably 25 mm, the inner diameter is preferably 15 mm, and the height is preferably 8 mm. This invention does not have particular requirements for the pressing pressure and time, as long as it can be pressed into a ring-shaped blank. In this invention, the density of the blank is preferably 3.0–3.15 g / cm³. 3 In specific embodiments of the present invention, it can be 3.0 g / cm³. 3 3.1g / cm 3 Or 3.15g / cm 3 .

[0076] After obtaining the blank, the present invention sinters the blank to obtain the manganese zinc ferrite material; the sintering temperature is 1150~1250℃.

[0077] In this invention, the sintering process preferably includes:

[0078] In air, the temperature is increased to 200°C at a rate of 2–5°C / min, and then increased to 300°C at a rate of 0.5–1°C / min.

[0079] The temperature is increased to 1100℃ at a heating rate of 0.5–3℃ / min, while the oxygen content of the sintering atmosphere at 1100℃ is 0.0–3.0%. Then the temperature is increased to 1150–1250℃ at a heating rate of 2–10℃ / min, while the oxygen content of the sintering atmosphere at 1150–1250℃ is 0.5–5.0%. The holding time at 1150–1250℃ is 150–300 min.

[0080] The temperature is lowered to 1000℃ at a cooling rate of 0.3–1.5℃ / min. During the cooling process to 1000℃, the oxygen content of the sintering atmosphere at 1100℃ is 0.5–1.0%, the oxygen content of the sintering atmosphere at 1050℃ is 0.1–0.3%, and the oxygen content of the sintering atmosphere at 1000℃ is 0.02–0.05%.

[0081] The temperature is lowered to 200℃ at a rate of 3–10℃ / min, while the oxygen content of the sintering atmosphere at 200℃ is ≤50ppm.

[0082] In this invention, the temperature is increased from room temperature to 200°C in air at a rate of 2 to 5°C / min. In embodiments of this invention, the heating rate can specifically be 2°C / min, 2.5°C / min, 3°C / min, 4°C / min, or 5°C / min.

[0083] The temperature is then increased to 300°C at a rate of 0.5 to 1°C / min. In embodiments of the present invention, the specific heating rate can be 0.5°C / min, 0.6°C / min, 0.8°C / min, or 1°C / min.

[0084] The PVA aqueous solution added during the granulation process of this invention will decompose and volatilize at 200-300℃. If the temperature rises too quickly at this stage, the PVA aqueous solution will volatilize violently, which can easily cause the blank to crack. Therefore, the temperature needs to be raised slowly at 200-300℃ to ensure that the PVA aqueous solution has enough time to volatilize.

[0085] The present invention heats the temperature to 1100°C at a heating rate of 0.5–3°C / min, while the oxygen content of the sintering atmosphere at 1100°C is 0.0–3.0%. In embodiments of the present invention, the heating rate can specifically be 0.5°C / min, 0.6°C / min, 1°C / min, 2°C / min, or 3°C / min, and the oxygen content of the sintering atmosphere at 1100°C can specifically be 0%, 0.05%, 0.1%, 0.2%, 0.5%, 1%, 1.5%, 2%, 2.5%, or 3%.

[0086] The temperature is then increased to 1150-1250°C at a heating rate of 2-10°C / min. In embodiments of the present invention, this can specifically be 1150°C, 1200°C, or 1250°C, and the heating rate can specifically be 2°C / min, 3°C / min, 5°C / min, 8°C / min, or 10°C / min. Simultaneously, the oxygen content of the sintering atmosphere at 1150-1250°C is 0.5-5.0%, and the holding time at 1150-1250°C is 150-300 min. In embodiments of the present invention, the oxygen content of the sintering atmosphere at 1150-1250°C can specifically be 0.5%, 1%, 2%, 3%, 4%, or 5%, and the holding time at 1150-1250°C can specifically be 150 min, 180 min, 200 min, 220 min, 250 min, or 300 min.

[0087] In the mid-to-high frequency range, eddy current loss is the main component of power consumption. Due to the high frequency, transgranular eddy currents can also occur due to grain boundary inhomogeneity. Therefore, the densification time should not be too short, and a heating rate of about 0.5–3℃ / min can ensure a relatively uniform grain structure. Simultaneously, reducing the oxygen content in the sintering atmosphere helps to promote the elimination of pores and the micro-densification of the material. By reducing the oxygen content in the sintering atmosphere to 0.5–5.0% and combining it with a holding time of 150–300 min, the material's permeability can be controlled at 2900–3500 and its density at 4.85–5.0 g / cm³. 3 The material exhibits good power consumption characteristics from 300kHz to 1MHz.

[0088] This invention cools the sintering atmosphere to 1000℃ at a cooling rate of 0.3–1.5℃ / min. During the cooling process to 1000℃, the oxygen content of the sintering atmosphere at 1100℃ is 0.5–1.0%, at 1050℃ it is 0.1–0.3%, and at 1000℃ it is 0.02–0.05%. In embodiments of this invention, the cooling rate can specifically be 0.3℃ / min, 0.5℃ / min, 1.0℃ / min, 1.2℃ / min, or 1.5℃ / min; the oxygen content of the sintering atmosphere at 1100℃ can specifically be 0.5%, 0.8%, or 1.0%; the oxygen content of the sintering atmosphere at 1050℃ can specifically be 0.1%, 0.2%, or 0.3%; and the oxygen content of the sintering atmosphere at 1000℃ can specifically be 0.02%, 0.025%, 0.03%, 0.04%, or 0.05%.

[0089] This invention employs a slow cooling method during the cooling process to 1000℃ after the heat preservation period, which ensures that impurities such as Ca and Si have sufficient time to migrate and segregate to the grain boundaries, thereby increasing the thickness of the grain boundary layer and improving the high-frequency power consumption characteristics of the material. Furthermore, by reducing the oxygen content of the sintering atmosphere at 1050℃ and 1000℃, this invention can prevent the formation of heterogeneous structures during the heat preservation stage, thus avoiding the deterioration of material performance.

[0090] The present invention cools down to 200°C at a cooling rate of 3 to 10°C / min, while the oxygen content of the sintering atmosphere at 200°C is ≤50ppm. In the embodiments of the present invention, the cooling rate can be 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min or 10°C / min.

[0091] Ferrites are typically sintered at temperatures between 1300 and 1400°C. This sintering temperature ensures sufficient density and permeability, resulting in low power consumption at 100 kHz. However, mid-to-high frequencies (300 kHz to 1 MHz) require smaller grain sizes. Therefore, a balance between doping and sintering temperature is necessary to achieve a material that maintains both a small grain size and high resistivity while retaining high density and permeability. Low-melting-point substances can also enter grain boundaries, increasing grain boundary resistance and reducing eddy current losses. Furthermore, CuO, V₂O₅, and other dopants such as SiO₂ and CaO further increase grain boundary resistance and reduce eddy current losses. Combined with low-temperature sintering ensuring a small grain size, manganese-zinc ferrite materials exhibit low eddy current losses at high frequencies. This invention uses CuO as a flux, along with V₂O₅ (melting point 690°C) and MoO₃ (795°C), enabling manganese-zinc ferrite materials to achieve high sintering densities (4.85–5.0 g / cm³) at relatively low sintering temperatures (1150–1250°C). 3 This results in fewer pores and defects inside the manganese-zinc ferrite material, less resistance to the movement of magnetic domain walls, and lower hysteresis loss, ensuring the low loss characteristics of the manganese-zinc ferrite material at medium frequencies, and the overall loss is also relatively low.

[0092] The method provided by this invention reduces the power consumption of manganese-zinc ferrite materials in the mid-to-high frequency band. With the development of emerging technologies such as artificial intelligence, the Internet of Things, and 5G communication, the demand for this material will increase, promoting the development of related industries.

[0093] To further illustrate the present invention, a manganese-zinc ferrite material and its preparation method provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0094] Example 1

[0095] Based on the total molar amount of the main components being 100%, the main components are: Fe2O3 52.1 mol%, ZnO2 9.0 mol%, CuO 0.2 mol%, with the balance being Mn3O4;

[0096] The auxiliary components, in percentage of the total mass of the main components, are: CaO 0.03%, SiO2 0.005%, Nb2O5 0.05%, Co2O3 0.3%, TiO2 0.05%, SnO2 0.05%, ZrO2 0.01%, V2O5 0.05%, MoO3 0.07%, and HfO2 0.05%.

[0097] According to the above component ratio, accurately weigh iron oxide red Fe2O3, CuO, Mn3O4 and ZnO, mix them and place them in a sand mill, add an appropriate amount of water (the mass ratio of water to the main component = 1:1), and then use the sand mill to mix them. The sand mill speed is 270 r / min and the mixing time is 60 min. After the mixing is completed, put the obtained sand slurry into an oven to dry it to obtain sand material.

[0098] The abrasive was ground finely, passed through a 100-mesh sieve, and then placed in a muffle furnace for pre-firing at a temperature of 860°C for 2.5 hours. After sufficient cooling, the pre-fired material was obtained.

[0099] The pre-burned material is sent back to the sand mill, and at the same time, auxiliary components and an appropriate amount of water (the mass ratio of water to the total mass of pre-burned material and auxiliary components = 1:1) are added to the sand mill. The sand mill speed is 270 r / min and the sand milling time is 2 h. After drying, a mixed sand abrasive is obtained with a D50 particle size of 1.0 μm.

[0100] The mixed abrasive sand and the binder polyvinyl alcohol aqueous solution (the mass concentration of the polyvinyl alcohol aqueous solution is 0.1%) are mixed and sprayed to granulate. The mass of the polyvinyl alcohol aqueous solution is 20% of the mass of the mixed abrasive sand to obtain granules.

[0101] The granular material was pressed to obtain 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 was 3.10 g / cm³. 3 ;

[0102] The blank is sintered in a bell-shaped furnace under atmosphere protection. The sintering steps are as follows:

[0103] The temperature was increased from room temperature to 200°C in air at a rate of 2.5°C / min, and then increased to 300°C at a rate of 1°C / min.

[0104] The temperature was increased to 1100℃ at a heating rate of 0.6℃ / min, while the oxygen content of the sintering atmosphere was reduced to 0.05% at 1100℃. Then the temperature was increased to 1250℃ at a heating rate of 5℃ / min, while the oxygen content of the sintering atmosphere was increased to 4% at 1250℃. The temperature was then held at 1250℃ for 300 min.

[0105] After the heat preservation is completed, the temperature is reduced to 1000℃ at a cooling rate of 1℃ / min. During the cooling process to 1000℃, the oxygen content of the sintering atmosphere is reduced. The oxygen content of the sintering atmosphere at 1100℃ is 0.5%, at 1050℃ it is 0.2%, and at 1000℃ it is 0.025%.

[0106] The temperature is reduced to 200℃ at a rate of 3℃ / min, while the oxygen content of the sintering atmosphere is reduced to ≤50ppm.

[0107] After sintering is completed, manganese-zinc ferrite material is obtained.

[0108] Example 2

[0109] The preparation steps are the same as in Example 1, except that the ratio of the main component and the auxiliary component is different. Specifically, based on the total molar amount of the main component as 100%, the main component is: Fe2O3 52.1 mol%, ZnO2 9.0 mol%, CuO 0.3 mol%, and the balance is Mn3O4.

[0110] The auxiliary components, in percentage of the total mass of the main components, are: CaO 0.05%, SiO2 0.005%, Nb2O5 0.05%, Co2O3 0.3%, TiO2 0.05%, SnO2 0.05%, ZrO2 0.01%, V2O5 0.05%, MoO3 0.05%, and HfO2 0.05%.

[0111] Example 3

[0112] The preparation steps are the same as in Example 1, except that the ratio of the main component and the auxiliary component is different. Specifically, based on the total molar amount of the main component as 100%, the main component is: Fe2O3 52.1 mol%, ZnO2 9.0 mol%, CuO 0.2 mol%, and the balance is Mn3O4.

[0113] The auxiliary components, in percentage of the total mass of the main components, are: CaO 0.05%, SiO2 0.005%, Nb2O5 0.03%, Co2O3 0.5%, TiO2 0.1%, SnO2 0.05%, ZrO2 0.01%, V2O5 0.05%, MoO3 0.05%, and HfO2 0.05%.

[0114] Comparative Example 1

[0115] The preparation steps are the same as in Example 1, except that Fe2O3 is 52.1 mol%, ZnO2 is 9.0%, and the balance is Mn3O4.

[0116] The auxiliary components, by mass percentage, are: CaO: 0.06%, SiO2: 0.005%, Nb2O5: 0.03%, Co2O3: 0.3%, TiO2: 0.05%, SnO2: 0.05%, ZrO2: 0.01%, V2O5: 0.05%;

[0117] The pressed blanks are sintered in a bell-shaped furnace under atmosphere protection. The sintering steps are as follows:

[0118] The temperature is increased to 200°C in air at a rate of 2.5°C / min, and then increased to 300°C at a rate of 1°C / min.

[0119] The temperature is increased to 1100℃ at a rate of 1.5℃ / min. During the cooling process to 1100℃, the oxygen content of the sintering atmosphere is reduced, and the oxygen content of the sintering atmosphere at 1100℃ is 0.05%. The temperature is then increased to 1330℃ at a rate of 5℃ / min, and the oxygen content of the sintering atmosphere is increased, and the oxygen content of the sintering atmosphere at 1330℃ is 5%. The temperature is then held at 1330℃ for 300 min.

[0120] After the heat preservation is completed, the temperature is reduced to 1000℃ at a cooling rate of 1℃ / min. At the same time, the oxygen content of the sintering atmosphere is reduced. The oxygen content of the sintering atmosphere at 1100℃ is 0.8%, at 1050℃ it is 0.5%, and at 1000℃ it is 0.025%.

[0121] The temperature is reduced to 200℃ at a rate of 5℃ / min, while the oxygen content of the sintering atmosphere is reduced to ≤50ppm.

[0122] The properties of the manganese-zinc ferrite materials in Examples 1-3 and Comparative Example 1 are shown in Table 1.

[0123] Table 1. Properties of manganese-zinc ferrite materials in Examples 1-3 and Comparative Example 1

[0124]

[0125] As shown in Table 1, compared with the comparative example, the manganese-zinc ferrite materials of Examples 1-3 have significantly reduced power consumption in the range of 300kHz to 1MHz.

[0126] Figure 1 The image shows a SEM image of the manganese-zinc ferrite material obtained in Example 1. Figure 2 The image shows a SEM image of the manganese-zinc ferrite material obtained in Comparative Example 1. Figures 1-2 It can be seen that the manganese zinc ferrite material obtained in Example 1 has smaller grains and a more uniform grain structure, resulting in lower power consumption in the 300kHz to 1MHz range.

[0127] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A manganese zinc ferrite material, characterized in that, The preparation raw material includes main components and auxiliary components; the main components include Fe2O352-55.5 mol%, ZnO 5.5-9.5 mol%, CuO 0.1-0.5 mol%, and the rest is Mn3O4, with the total mole of the main components being 100%; The auxiliary component comprises, in percentage of the total mass of the main component: CaO 0.03-0.2%, SiO2 0.005-0.03%, 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%, HfO2 0.05-0.2%; the density of the manganese-zinc ferrite material is 4.85-5.0 g / cm3 3 . The preparation method of the manganese-zinc ferrite material includes the following steps: The main components are sand milled to obtain sand milling material; The sand milling material is pre-fired to obtain pre-fired material; The pre-fired material and the auxiliary components are mixed and sand milled to obtain mixed sand milling material; The mixed sand milling material and the binder are mixed and formed to obtain a blank; The blank is sintered to obtain the manganese-zinc ferrite material; the sintering temperature is 1150-1250℃; The sintering process includes: The temperature is raised to 200℃ at a temperature rising speed of 2-5℃ / min in air, and then raised to 300℃ at a temperature rising speed of 0.5-1℃ / min; The temperature is raised to 1100℃ at a temperature rising speed of 0.5-3℃ / min, while the oxygen content of the sintering atmosphere at 1100℃ is 0.0-3.0%, and then raised to 1150-1250℃ at a temperature rising speed of 2-10℃ / min, while the oxygen content of the sintering atmosphere at 1150-1250℃ is 0.5-5.0%, and the holding time at 1150-1250℃ is 150-300min; The temperature is lowered to 1000℃ at a temperature lowering speed of 0.3-1.5℃ / min, while the oxygen content of the sintering atmosphere at 1100℃ is 0.5-1.0%, the oxygen content of the sintering atmosphere at 1050℃ is 0.1-0.3%, and the oxygen content of the sintering atmosphere at 1000℃ is 0.02-0.05%; The temperature is lowered to 200℃ at a temperature lowering speed of 3-10℃ / min, while the oxygen content of the sintering atmosphere at 200℃ is ≤50ppm.

2. The Mn-Zn ferrite material according to claim 1, characterized in that, The initial permeability of the manganese-zinc ferrite material is 2900-3500.

3. The method of producing the manganese zinc ferrite material according to claim 1 or 2, characterized by, The preparation method includes the following steps: The main components are sand milled to obtain sand milling material; The sand milling material is pre-fired to obtain pre-fired material; The pre-fired material and the auxiliary components are mixed and sand milled to obtain mixed sand milling material; The mixed sand milling material and the binder are mixed and formed to obtain a blank; The blank is sintered to obtain the manganese-zinc ferrite material; The sintering temperature is 1150-1250℃; The sintering process includes: The temperature is raised to 200℃ at a temperature rising speed of 2-5℃ / min in air, and then raised to 300℃ at a temperature rising speed of 0.5-1℃ / min; The temperature is raised to 1100℃ at a temperature rising speed of 0.5-3℃ / min, while the oxygen content of the sintering atmosphere at 1100℃ is 0.0-3.0%, and then raised to 1150-1250℃ at a temperature rising speed of 2-10℃ / min, while the oxygen content of the sintering atmosphere at 1150-1250℃ is 0.5-5.0%, and the holding time at 1150-1250℃ is 150-300min; cooling to 1000℃ at a cooling rate of 0.3-1.5℃ / min, wherein the oxygen content of the sintering atmosphere is 0.5-1.0% at 1100℃, 0.1-0.3% at 1050℃, and 0.02-0.05% at 1000℃; cooling to 200℃ at a cooling rate of 3-10℃ / min, wherein the oxygen content of the sintering atmosphere is ≤50ppm at 200℃.

4. The production method according to claim 3, characterized by, The pre-sintering temperature is 840-940℃, and the holding time is 0.5-3h.

5. The production method according to claim 3 or 4, characterized by, The D50 particle size of the mixed sand abrasive is 1.0μm.

6. The preparation method according to claim 3, characterized in that, The binder comprises a polyvinyl alcohol aqueous solution.

7. The preparation method according to claim 3, characterized in that, The blank is a ring-shaped blank.

8. The production method according to claim 3 or 7, characterized by, The density of the blank is 3.0-3.15 g / cm 3 .

9. The production method according to claim 3 or 4, characterized by, The rotation speed for sanding the main component is 270r / min, and the time is 30-60min.

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