A lean iron-manganese-zinc ferrite material and its preparation method

Abstract

This invention relates to the field of ferrite preparation technology, specifically providing a lean iron-manganese-zinc ferrite material and its preparation method. The lean iron-manganese-zinc ferrite material comprises main components and auxiliary components. Based on a total weight of 100 wt% of the main components, the main components include: 65-67 wt% Fe2O3, 10-12 wt% ZnO, and the remainder being Mn3O4. Based on the total weight of the main components, the auxiliary components include 100-2000 ppm CaCO3 and 1000-10000 ppm Co2O3. By controlling the content of Fe2O3, ZnO, Mn3O4, CaCO3, and Co2O3 in the formula, the lean iron-manganese-zinc ferrite material of this invention exhibits characteristics of low-temperature high permeability, high Curie temperature, and high-frequency high impedance.

Description

Technical Field

[0001] This invention relates to the field of ferrite preparation technology, specifically to a lean iron-manganese-zinc ferrite material and its preparation method. Background Technology

[0002] Electronic products have become indispensable for human work, leisure, entertainment, learning, and video conferencing. While bringing convenience, they also contribute to environmental pollution—electromagnetic interference. High-permeability manganese-zinc ferrite is widely used in signal transmission and electromagnetic interference suppression technologies; however, its high permeability, low resistivity, and low cutoff frequency limit its application to low-frequency bands. Nickel-zinc ferrite, with its high resistivity, high cutoff frequency, and high impedance at high frequencies, is widely used in high-frequency filtering. Its drawbacks include low permeability, poor low-frequency filtering, and high cost. While nanocrystalline materials can be used for both low- and high-frequency filtering, their limited availability restricts their use to simple core shapes and high cost. For these reasons, scientists discovered iron-poor manganese-zinc ferrite materials, which offer advantages such as high permeability, high Curie temperature, high impedance at high frequencies, and low cost, gaining popularity among customers.

[0003] Currently, only a few companies have achieved mass production of lean iron-manganese-zinc ferrite materials. For example, Anci's JPZ-4 material has a permeability of 4000 and a Curie temperature >105℃, indicating high permeability, but a low Curie temperature limits its application range. Dongci's DMR31 material has a permeability of 2000 and a Curie temperature of 160℃, but its permeability drops to only 750 at -40℃. Tiantong's Ti30 material has a permeability of 3000 but a Curie temperature of only 130℃.

[0004] Chinese invention patent CN110156451B authorizes a high-impedance iron-poor manganese-zinc ferrite material. By limiting the content of iron oxide to 46-49.8 mol%, the content of zinc oxide to 17-23 mol%, and the remainder to manganese oxide, the permeability of the manganese-zinc ferrite material is achieved to be μi = 2500 ± 25%, and it has good high impedance performance under the conditions of 1MHz to 500MHz.

[0005] Chinese invention patent CN115650715A discloses a broadband, high impedance, and high resistivity manganese-zinc ferrite material. By limiting the content of iron oxide to 40.5–45.5 mol%, the content of manganese oxide to 36–40 mol%, and the remainder to zinc oxide, the broadband, high impedance, and high resistivity manganese-zinc ferrite material is achieved.

[0006] Chinese invention patent CN111138180A discloses a wide-temperature, high-permeability manganese-zinc ferrite material. By limiting the content of iron oxide to 46-50 mol%, the content of zinc oxide to 9-12.9 mol%, and the remainder to manganese oxide, the manganese-zinc ferrite achieves a permeability >1000, a Curie temperature >180℃, and wide-frequency, high-impedance performance.

[0007] To cope with harsh application environments, electronic products are required to maintain high permeability at low temperatures (e.g., -40°C) to ensure equipment efficiency and stability. Using the permeability at standard room temperature (25°C) as a benchmark, the permeability of manganese-zinc ferrite materials typically drops to below 50% of the standard room temperature permeability when the temperature decreases from 25°C to -40°C. This significantly reduces the efficiency of manganese-zinc ferrite materials at low temperatures, making them unsuitable for use in special environments. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the defect of existing iron-poor manganese-zinc ferrite materials that cannot maintain high magnetic permeability at low temperature while having a high Curie temperature, thereby providing an iron-poor manganese-zinc ferrite material and its preparation method.

[0009] Therefore, the present invention provides a lean iron-manganese-zinc ferrite material, comprising a main component and auxiliary components. The main component, based on a total weight of 100 wt%, comprises: 65-67 wt% Fe2O3, 10-12 wt% ZnO, and the remainder Mn3O4. The auxiliary components, based on their weight percentage of the main component, comprise 100-2000 ppm CaCO3 and 1000-10000 ppm Co2O3.

[0010] Furthermore, the permeability of the iron-poor manganese-zinc ferrite material is 1600-2400 at -40℃ and 25℃.

[0011] Furthermore, the Curie temperature of the iron-poor manganese-zinc ferrite material is above 160°C.

[0012] Secondly, the present invention also provides a method for preparing any of the above-mentioned iron-poor manganese-zinc ferrite materials, comprising mixing Fe2O3, ZnO, and Mn3O4 in a certain proportion, grinding the mixture once, pre-firing to obtain a pre-fired material, mixing the pre-fired material with auxiliary components, and grinding the mixture a second time, granulating, molding, and sintering to obtain the iron-poor manganese-zinc ferrite material.

[0013] Furthermore, the first grinding is wet ball milling, preferably, the wet ball milling time is 30-120 min; preferably, during the wet ball milling process, the mass ratio of grinding media, mixture and water is 4:0.8-1.2:0.8-1.2.

[0014] Furthermore, the pre-firing temperature is 980-1035℃, and the rate is 400-500 kg / h.

[0015] The pre-firing process uses a rotary kiln, and the pre-firing speed refers to the car feed speed.

[0016] Furthermore, the process before secondary grinding also includes a step of mixing in a binder and a dispersant;

[0017] Preferably, the adhesive comprises a PVA adhesive;

[0018] Preferably, the dispersant comprises citric acid;

[0019] Preferably, the binder accounts for 5-10 wt% of the total mass of the pre-fired material;

[0020] Preferably, the dispersant accounts for 1 to 2 wt% of the total mass of the pre-burned material.

[0021] Furthermore, the secondary grinding is wet ball milling, preferably, the wet ball milling time is 120-150 min; preferably, during the wet ball milling process, the mass ratio of grinding media, mixture and water is 4:0.8-1.2:0.8-1.2.

[0022] Further, the sintering is carried out at 1300-1400°C for 4-10 hours under a mixed atmosphere of nitrogen and air or oxygen, with the oxygen content controlled at 3-21 vol%, followed by cooling under equilibrium oxygen partial pressure; preferably, the sintering is carried out at 1320-1340°C for 6-8 hours under a mixed atmosphere of nitrogen and air or oxygen, with the oxygen content controlled at 20-21 vol%, followed by cooling under equilibrium oxygen partial pressure.

[0023] The equilibrium oxygen partial pressure in the method of this invention is calculated according to the formula lg(P(O2))=ab / T, where a takes the value of 5-10, b takes the value of 10000~15000, and T is the absolute temperature.

[0024] Furthermore, the granulation is spray granulation; and / or the molding is compression molding.

[0025] The technical solution of this invention has the following advantages:

[0026] 1. The iron-manganese-zinc ferrite material provided by this invention comprises a main component and auxiliary components. Based on the total weight of the main component (100 wt%), the main component includes: 65-67 wt% Fe₂O₃, 10-12 wt% ZnO, and the remainder being Mn₃O₄. Based on the total weight of the main component, the auxiliary components include 100-2000 ppm CaCO₃ and 1000-10000 ppm Co₂O₃. By controlling the content of Fe₂O₃, ZnO, Mn₃O₄, CaCO₃, and Co₂O₃ within the above ranges, the iron-manganese-zinc ferrite material of this invention exhibits characteristics of high permeability at low temperatures, high Curie temperature, and high impedance at high frequencies, thereby enabling the magnetic core to have excellent filtering performance at low temperatures (-40℃). Simultaneously, the Curie temperature of 160℃ can meet higher environmental temperature requirements, ensuring the material operates under both lower and higher temperature conditions.

[0027] Generally, the anisotropy constant of spinel ferrite is negative, while the anisotropy constant of CoO is K1 > 0. After adding Co2O3, K1 approaches 0, which is beneficial to improving the permeability.

[0028] 2. The iron-manganese-zinc ferrite material provided by the present invention comprises mixing Fe2O3, ZnO, and Mn3O4 in a certain proportion, grinding the mixture once, pre-firing to obtain a pre-fired material, mixing the pre-fired material with auxiliary components, grinding the mixture a second time, granulating, molding, and sintering to obtain the iron-manganese-zinc ferrite material. The preparation method is simple, convenient to operate, and suitable for industrial production. The sintering is carried out at 1300-1400℃ for 4-10 hours under a nitrogen atmosphere with an oxygen content controlled at 3-21 vol%, followed by cooling under equilibrium oxygen partial pressure. Preferably, the sintering is carried out at 1320-1340℃ for 6-8 hours under a nitrogen atmosphere with an oxygen content controlled at 20-21 vol%, followed by cooling under equilibrium oxygen partial pressure. Under the above sintering conditions, iron-manganese-zinc ferrite materials with better performance can be obtained. Detailed Implementation

[0029] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0030] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0031] Example 1

[0032] This embodiment provides a lean iron-manganese-zinc ferrite material and its preparation method, including the following steps:

[0033] (1) Ingredients: The components were weighed in the following weight ratios as main components: Fe2O3: 66.4wt%, Mn3O4: 22.6wt%, and ZnO: 11wt%. The components were weighed in the following weight ratios as auxiliary components: CaCO3: 200ppm and Co2O3: 7000ppm, based on the total mass of the main components.

[0034] (2) First grinding: Add steel balls and water to the main component in a ball mill and mix for 30 minutes, wherein the mass ratio of steel balls, main component and water is 4:1:1.

[0035] (3) Pre-calcination: The slurry after removing the steel balls is sprayed into the rotary kiln through a spray gun and pre-calcined at 1020℃ at a rate of 450Kg / h to obtain the pre-calcined material.

[0036] (4) Secondary grinding: Weigh 400 kg of pre-burned material and put it into a sand mill. Then add 200 ppm CaCO3, 7000 ppm Co2O3, 32 kg of PVA glue and 6 kg of citric acid dispersant to obtain a mixture. Add steel balls and water balls and grind for 150 min. The mass ratio of steel balls, mixture and water is 4:1:1.

[0037] (5) Granulation and molding: After the composition of the ball-milled slurry is analyzed and corrected, it is then spray-granulated to obtain ferrite particles; the ferrite particles are pressed into blank samples of H25×15×8.

[0038] (6) Sintering: Sinter at 1330°C for 7 hours under the conditions of N2 content of 79 vol% and oxygen content of 21 vol%. The cooling stage is carried out under the equilibrium oxygen partial pressure to obtain the magnetic core.

[0039] Example 2

[0040] This embodiment provides a lean iron-manganese-zinc ferrite material and its preparation method, including the following steps:

[0041] (1) Ingredients: Weigh each component as the main component according to the weight ratio of Fe2O3: 66.4wt%, Mn3O4: 22.6wt%, ZnO: 11wt%. Weigh each component as the auxiliary component according to the weight ratio of 1200ppm CaCO3 and 6000ppm Co2O3 based on the total mass of the main components.

[0042] (2) First grinding: Mix the main components in a ball mill for 60 minutes, wherein the mass ratio of steel balls, mixture and water is 4:1.2:1.2.

[0043] (3) Pre-calcination: The slurry after removing the steel balls is sprayed into the rotary kiln through a spray gun and pre-calcined at 1020℃ at a rate of 450Kg / h to obtain the pre-calcined material.

[0044] (4) Secondary grinding: Weigh 400 kg of pre-burned material and put it into a sand mill. Then add auxiliary components, 40 kg of PVA glue and 4 kg of citric acid dispersant. Ball mill for 120 min. The mass ratio of steel balls, mixture and water is 4:1:1.

[0045] (5) Granulation and molding: After the ball milled slurry is corrected by composition analysis, it is then spray granulated to obtain ferrite particles; the ferrite particles are pressed into blank samples of H25×15×8.

[0046] (6) Sintering: Sinter at 1340℃ for 7 hours under the conditions of N2 content of 80 vol% and oxygen content of 20 vol%. The cooling stage is carried out under the equilibrium oxygen partial pressure to obtain the magnetic core.

[0047] Example 3

[0048] This embodiment provides a lean iron manganese zinc ferrite material and its preparation method. The difference from Embodiment 1 is that in step (1), the main components are in the following ratio: Fe2O3: 66.2wt%, Mn3O4: 23wt%, ZnO: 10.8wt%. Based on the total mass of the main components, each component is weighed as an auxiliary component according to the weight ratio of 200ppm CaCO3 and 8000ppm Co2O3.

[0049] Example 4

[0050] This embodiment provides a lean iron manganese zinc ferrite material and its preparation method. The difference from Embodiment 1 is that in step (1), the main components are in the following ratio: Fe2O3: 65.8wt%, Mn3O4: 23.8wt%, ZnO: 10.4wt%. Based on the total mass of the main components, each component is weighed as an auxiliary component according to the weight ratio of 200ppm CaCO3 and 10000ppm Co2O3.

[0051] Example 5

[0052] This embodiment provides a lean iron manganese zinc ferrite material and its preparation method. The difference from Embodiment 1 is that the sintering temperature and time are different. In this embodiment, the material is sintered at 1300℃ for 9 hours.

[0053] Example 6

[0054] This embodiment provides a lean iron-manganese-zinc ferrite material and its preparation method. The difference from Embodiment 1 is that the sintering temperature and time are different. In this embodiment, the material is sintered at 1350°C for 5 hours.

[0055] Example 7

[0056] This embodiment provides a lean iron manganese zinc ferrite material and its preparation method. The difference from Embodiment 1 is that the CaCO3 content in step (1) is different. In this embodiment, the weight ratio of CaCO3 in the auxiliary component is 100ppm based on the total mass of the main component.

[0057] Comparative Example 1

[0058] This comparative example provides a lean iron manganese zinc ferrite material and its preparation method. The difference from Example 1 is that the content of the main component in step (1) is different. The main components in this comparative example are in the following ratio: Fe2O3: 66.4wt%, Mn3O4: 21.1wt%, ZnO: 12.5wt%.

[0059] Comparative Example 2

[0060] This comparative example provides a lean iron manganese zinc ferrite material and its preparation method. The difference between this and Example 1 is that the content of the main component in step (1) is different. The main components in this comparative example are in the following ratio: Fe2O3: 66.4wt%, Mn3O4: 24.2wt%, ZnO: 9.4wt%.

[0061] Comparative Example 3

[0062] This comparative example provides a lean iron manganese zinc ferrite material and its preparation method. The difference from Example 1 is that the content of the main component in step (1) is different. The main components in this comparative example are in the following ratio: Fe2O3: 64.3wt%, Mn3O4: 24.7wt%, ZnO: 11wt%.

[0063] Comparative Example 4

[0064] This comparative example provides a lean iron manganese zinc ferrite material and its preparation method. The difference between this and Example 1 is that the content of the main component in step (1) is different. The main component in this comparative example adopts the following ratio: Fe2O3: 68wt%, Mn3O4: 21wt%, ZnO: 11wt%.

[0065] Comparative Example 5

[0066] This comparative example provides a lean iron manganese zinc ferrite material and its preparation method. The difference from Example 1 is that the Co2O3 content in step (1) is different. In this comparative example, the weight ratio of Co2O3 in the auxiliary component is 500ppm based on the total mass of the main component.

[0067] Comparative Example 6

[0068] This comparative example provides a lean iron manganese zinc ferrite material and its preparation method. The difference from Example 1 is that the Co2O3 content in step (1) is different. In this comparative example, the weight ratio of Co2O3 in the auxiliary component is 15000ppm based on the total mass of the main component.

[0069] Comparative Example 7

[0070] This comparative example provides a lean iron manganese zinc ferrite material and its preparation method. The difference from Example 1 is that the CaCO3 content in step (1) is different. In this comparative example, the weight ratio of CaCO3 in the auxiliary component is 2500ppm based on the total mass of the main component.

[0071] The initial permeability μi and Curie temperature of the iron-poor manganese-zinc ferrite materials prepared in each embodiment and comparative example were tested at room temperature and at -40°C. The test conditions were frequency f = 10 kHz and voltage u = 0.25 V. The results are shown in Table 1 below.

[0072] Table 1 Performance Test Results

[0073]

[0074] Table 2 Performance Test Results

[0075]

[0076]

[0077] As shown in the table above, compared to Comparative Examples 2 and 4-7, the iron-depleted manganese-zinc ferrite materials prepared in the embodiments of the present invention not only significantly improve the low-temperature permeability but also maintain a Curie temperature above 160°C, thus achieving a balance of high permeability at low temperatures, high Curie temperature, and high impedance at high frequencies. Compared to Comparative Examples 1 and 3, the Curie temperature of the iron-depleted manganese-zinc ferrite materials prepared in the embodiments of the present invention is significantly increased.

[0078] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A lean iron-manganese-zinc ferrite material, characterized in that, The iron-manganese-zinc ferrite material comprises a main component and auxiliary components. The main component, based on a total weight of 100 wt%, comprises: 65-67 wt% Fe2O3, 10-12 wt% ZnO, and the remainder Mn3O4. The auxiliary components, based on their weight percentage of the main component, are 100-2000 ppm CaCO3 and 1000-10000 ppm Co2O3. The preparation method of the iron-poor manganese-zinc ferrite material includes mixing Fe2O3, ZnO, and Mn3O4 in a certain proportion, grinding the mixture once, pre-firing to obtain a pre-fired material, mixing the pre-fired material with auxiliary components, grinding the mixture a second time, granulating, molding, and sintering to obtain the iron-poor manganese-zinc ferrite material.

2. The lean iron-manganese-zinc ferrite material according to claim 1, characterized in that, The iron-poor manganese-zinc ferrite material has an initial magnetic permeability of 1600-2400 at -40℃ and 25℃.

3. The lean iron manganese zinc ferrite material according to claim 1 or 2, characterized in that, The Curie temperature of the iron-poor manganese-zinc ferrite material is above 160°C.

4. The lean iron-manganese-zinc ferrite material according to claim 1, characterized in that, The first grinding process is wet ball milling.

5. The lean iron manganese zinc ferrite material according to claim 4, characterized in that, The wet ball milling time is 30-120 min; And / or, in the wet ball milling process, the mass ratio of grinding media, mixture and water is 4:0.8-1.2:0.8-1.

2.

6. The lean iron manganese zinc ferrite material according to claim 1, characterized in that, The pre-firing temperature is 980-1035℃, and the rate is 400-500 kg / h.

7. The lean iron-manganese-zinc ferrite material according to claim 1, characterized in that, The secondary grinding process also includes a step of mixing in a binder and a dispersant.

8. The lean iron-manganese-zinc ferrite material according to claim 7, characterized in that, The adhesive includes PVA adhesive; And / or, the dispersant includes citric acid; And / or, the binder accounts for 5-10 wt% of the total mass of the pre-fired material; And / or, the dispersant accounts for 1 to 2 wt% of the total mass of the pre-burned material.

9. The lean iron-manganese-zinc ferrite material according to claim 7, characterized in that, The secondary grinding is wet ball milling.

10. The lean iron manganese zinc ferrite material according to claim 9, characterized in that, The wet ball milling time is 120-150 min; And / or, in the wet ball milling process, the mass ratio of grinding media, mixture and water is 4:0.8-1.2:0.8-1.

2.

11. The lean iron-manganese-zinc ferrite material according to claim 1, characterized in that, The sintering process involves sintering at 1300-1400°C for 4-10 hours under a mixed atmosphere of nitrogen and air or oxygen, with the oxygen content controlled at 3-21 vol%, followed by cooling under balanced oxygen partial pressure.

12. The lean iron manganese zinc ferrite material according to claim 1, characterized in that, The sintering process involves sintering at 1320-1340°C for 6-8 hours under a mixed atmosphere of nitrogen and air or oxygen, with the oxygen content controlled at 20-21 vol%, followed by cooling under balanced oxygen partial pressure.

13. The lean iron manganese zinc ferrite material according to any one of claims 1-12, characterized in that, The granulation is spray granulation; and / or the molding is compression molding.

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