Method for preparing ultrahigh-frequency low-loss MnZn power ferrite material

Abstract

The invention relates to a method for preparing an ultrahigh-frequency low-loss MnZn power ferrite material. The ultrahigh-frequency low-loss MnZn power ferrite material comprises main components and auxiliary components, the main component is prepared from the following components in percentage by mass: 68.0 to 69.4 weight percent of Fe2O3, 22.8 to 23.8 weight percent of Mn3O4 and 7.6 to 8.0 weight percent of ZnO, and the total amount is 100 weight percent; and the auxiliary components comprise the following components in percentage by mass in the main components: 200 to 600 ppm of Y2O3 and 200 to 800 ppm of Tb2O3. The MnZn power ferrite material is compositely doped with lanthanide-containing ions Tb2O3 and Y2O3, so that the win-win situation of performance and cost is realized, the loss of the prepared MnZn power ferrite material is 234 mW.cm <-3 > and 298 mW.cm <-3 > respectively under the test conditions of room temperature of 1 MHz and 30 mT and room temperature of 3 MHz and 10 mT, and the MnZn power ferrite material is a potential material capable of being used in the MHz-level high-frequency field and has a wide application prospect. And the problems of high loss, high heat production, low efficiency and short service life of the material under high frequency can be solved.

Description

Technical Field

[0001] The invention relates to a method for preparing an ultra-high frequency low-loss MnZn power ferrite material, belonging to the technical field of ferrite material preparation. Background Art

[0002] With the rapid development of 5G communications, electric vehicles, wireless charging, and high-frequency power supply technologies, electronic devices are placing higher demands on the performance of magnetic materials under high-frequency conditions. MnZn power ferrite materials are widely used in traditional low-frequency applications due to their high magnetic permeability and low cost.

[0003] However, conventional MnZn power ferrite materials are prone to increased power loss and decreased magnetic permeability under high-frequency operating conditions, making them difficult to meet the high-frequency, miniaturized, and energy-efficient demands of the next generation of electronic devices. Therefore, the development of MnZn power ferrite materials with low loss, high stability, and excellent high-frequency magnetic properties has become a research hotspot in the field of magnetic materials.

[0004] In the increasingly competitive magnetic materials market, manufacturers must continuously develop new products and improve material performance to enhance their competitiveness in order to meet ever-changing market demands and the stringent requirements of high-end applications. The current development trend for MnZn power ferrites is toward high frequency and low loss, suitable for miniaturized and high-frequency applications. However, in the research and development and production of high-frequency ferrites, domestic products still lag significantly behind cutting-edge international technology. Furthermore, controlling production costs is also a key concern for manufacturers of MnZn power ferrite materials.

[0005] By regulating factors such as chemical composition, type and content of doping elements, sintering process parameters, and oxygen partial pressure, its microstructure and electromagnetic properties can be effectively optimized, providing material support for its application in key components such as high-frequency transformers, inductors, and magnetic cores. Among them, rare earth ions, as an effective dopant, have attracted a large number of researchers and manufacturers to explore how to use them to regulate the performance of MnZn power ferrite materials. However, in actual production, not only product performance but also the cost of the dopant must be considered. How to achieve a win-win situation in performance and cost is the main demand of researchers and manufacturers, and it is also the key problem that this invention aims to solve. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention provides a method for preparing an ultra-high frequency low-loss MnZn power ferrite material.

[0007] The technical solutions of the present invention are as follows: An ultra-high frequency low-loss MnZn power ferrite material, comprising a main component and an auxiliary component; The main components are calculated by weight percentage, including: Fe2O3 68.0-69.4wt%, Mn3O4 22.8-23.8wt%, ZnO 7.6-8.0wt%, with a total amount of 100wt%; The mass content of the auxiliary components in the main components is: Y2O3 200-600ppm, Tb2O3 200-800ppm.

[0008] According to the preferred embodiment of the present invention, the main components are calculated by mass percentage and include: Fe2O3 69wt%, Mn3O4 23wt%, ZnO 8wt%, with a total amount of 100wt%; The mass content of the auxiliary components in the main components is: Tb2O3400ppm, Y2O3400ppm.

[0009] A method for preparing an ultra-high frequency low-loss MnZn power ferrite material comprises the following steps: (1) Weigh the main raw materials Fe2O3, Mn3O4, and ZnO according to the ratio, perform a ball milling process, and then dry the ball milled slurry to obtain the main component powder; (2) pre-calcining the main component powder obtained in step (1), and cooling it to obtain a main component pre-calcined material; (3) According to the proportion, the main component pre-sintered material obtained in step (2) is mixed with the auxiliary component raw materials Tb2O3 and Y2O3, and a secondary ball milling treatment is performed. The ball milled slurry is then dried to obtain a mixed powder; (4) adding a polyvinyl alcohol aqueous solution to the mixed powder obtained in step (3), uniformly granulating the mixture in a mechanical granulator, and sieving the mixture to obtain granular material; (5) The granular material obtained in step (4) is pressed and sintered in sequence to obtain an ultra-high frequency low-loss MnZn power ferrite material.

[0010] Preferably, according to the present invention, in step (1), the primary ball milling is carried out in a ball mill, the ball milling time is 60-70 min, the mass ratio of steel balls, raw materials and deionized water during the ball milling process is 3:1:1, and the ball mill speed is 280-320 rpm.

[0011] According to the preferred embodiment of the present invention, in step (1), the average particle size of the main component powder is ≤1.1 μm.

[0012] Preferably, according to the present invention, in step (2), the pre-firing temperature is 900-1000° C., and the pre-firing time is 1.5-2.5 hours.

[0013] Preferably, according to the present invention, in step (3), the secondary ball milling is carried out in a ball mill, the ball milling time is 300-400 min, the mass ratio of steel balls, raw materials and deionized water during the ball milling process is 5:1:1, and the ball mill speed is 330-370 rpm.

[0014] Preferably, according to the present invention, in step (3), the average particle size of the mixed powder is 1-1.2 μm.

[0015] Preferably, according to the present invention, in step (4), the mass concentration of the polyvinyl alcohol aqueous solution is 3-5%, and the mass ratio of the polyvinyl alcohol aqueous solution to the mixed powder is (5-10):100.

[0016] Preferably, according to the present invention, in step (4), the granulation time is 100-200 s, and the granulation rotation speed is 5000-6000 r.

[0017] According to the preferred embodiment of the present invention, in step (5), the pressing is performed at 400 MPa to form a magnetic ring.

[0018] According to the preferred embodiment of the present invention, in step (5), the sintering is to place the magnetic ring in a sintering device, sinter at 1150-1200°C for 30-60 minutes, and then cool to below 300°C.

[0019] More preferably, the sintering is to sinter the magnetic ring at 1180° C. for 30 minutes.

[0020] The above-mentioned ultra-high frequency low-loss MnZn power ferrite material is used in the fields of aerospace or automotive electronics.

[0021] Anything not described in detail in the present invention can be carried out according to the existing technology.

[0022] Technical features and beneficial effects of the present invention: 1. The present invention is the first to use high resistivity and high melting point materials Tb2O3 and Y2O3 to prepare MnZn power ferrite materials. Y2O3 and Tb2O3 are added as auxiliary components to modify MnZn ferrite, and the two rare earth ions (Tb 3 + and Y 3+ ) have ionic radii larger than Fe 3+Due to their large ionic radius, they are less likely to enter the crystal lattice and instead accumulate at grain boundaries, inhibiting their movement and thus limiting grain growth. This increases the number of grain boundaries within the sample, thereby increasing the resistivity of the MnZn ferrite material, reducing grain size, and lowering eddy current losses, thereby improving the performance of MnZn ferrite at high and ultra-high frequencies (1MHz / 3MHz). Furthermore, the material has a high cutoff frequency, which means that resonance is not easily excited, resulting in very low or even negligible residual losses. Therefore, the total loss of MnZn ferrite at ultra-high frequencies is low.

[0023] 2. The present invention can achieve performance improvement and cost control by only composite doping with lanthanide ions Tb2O3 and Y2O3 without adding other conventional additives (such as CaO, Co2O3, SiO2, etc.), thus achieving a win-win situation in terms of performance and cost. The prepared MnZn power ferrite material has a loss of 234mW·cm under the test conditions of 1MHz, 30mT and 3MHz, 10mT at room temperature, respectively. -3 and 298 mW·cm -3 , a potential material for use in the 3MHz ultra-high frequency field, helping to address the high loss, high heat generation, low efficiency, and short material life issues associated with high and ultra-high frequencies. Furthermore, the addition of Tb2O3 and Y2O3 reduces grain size, contributing to lower overall losses. The addition of multiple ions alters the microscopic composition of the ferrite material, changing its electromagnetic properties and contributing to lower losses. Furthermore, considering the cost of additives in large-scale production, the use of lower-cost Y2O3 ensures performance while reducing production costs, providing a new approach and method for the research and development of magnetic materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 These are XRD patterns of the MnZn power ferrite materials prepared in Examples 1-3 and Comparative Examples 1-2 of the present invention.

[0025] Figure 2 This is a cross-sectional morphology of the MnZn power ferrite material prepared in Example 1.

[0026] Figure 3 This is a cross-sectional morphology of the MnZn power ferrite material prepared in Example 2.

[0027] Figure 4 This is a cross-sectional morphology of the MnZn power ferrite material prepared in Example 3.

[0028] Figure 5 This is a cross-sectional morphology of the MnZn power ferrite material prepared in Comparative Example 1.

[0029] Figure 6This is the cross-sectional morphology of the MnZn power ferrite material prepared in Comparative Example 2. DETAILED DESCRIPTION

[0030] The present invention is further described below by way of specific examples and accompanying drawings, but the scope of the invention is not limited thereto. The raw materials used in the examples are all conventional raw materials, and the equipment used are all conventional equipment, which can be purchased from commercial sources.

[0031] Example 1 An ultra-high frequency low-loss MnZn power ferrite material, comprising a main component and an auxiliary component; The main components, in terms of mass percentage, include: Fe2O3 69wt%, Mn3O4 23wt%, and ZnO 8wt%; The mass content of the auxiliary components in the main component is: Tb2O3400ppm, Y2O3400ppm.

[0032] A method for preparing an ultra-high frequency low-loss MnZn power ferrite material comprises the following steps: (1) The main component raw materials Fe2O3, Mn3O4, and ZnO were weighed according to the ratio and ball milled in a ball mill for 65 min. The mass ratio of steel balls, raw materials, and deionized water was 3:1:1 during the ball milling process, and the ball mill speed was 300 rpm. The slurry was then dried to obtain the main component powder with an average particle size of 0.8-1.1 μm. (2) pre-calcining the main component powder obtained in step (1) at 950° C. for 2 hours and naturally cooling the main component pre-calcined material; (3) According to the proportion, the main component pre-sintered material obtained in step (2) is mixed with the auxiliary component raw materials Tb2O3 and Y2O3, and a secondary ball milling treatment is carried out in a ball mill. The ball milling time is 350 min. During the ball milling process, the mass ratio of steel balls, raw materials and deionized water is 5:1:1, and the ball mill speed is 350 rpm. The slurry is then dried to obtain a mixed powder with an average particle size of 1-1.2 μm. (4) Adding a polyvinyl alcohol aqueous solution having a mass concentration of 4% to the mixed powder obtained in step (3), with the mass ratio of the polyvinyl alcohol aqueous solution to the mixed powder being 8:100; then uniformly granulating the mixture in a mechanical granulator for 150 seconds at a rotation speed of 5500 r to obtain granules, followed by sieving with a 100-mesh sieve to obtain granules; (5) The granular material obtained in step (4) is pressed into a 26*16*5 mm magnetic ring green body at 400 MPa, and then the magnetic ring green body is placed in a sintering device and sintered at 1180°C in a nitrogen and oxygen mixed gas of 3.5% O2+96.5% N2 for 60 minutes. After cooling to below 300°C in nitrogen, the magnetic ring is taken out to obtain an ultra-high frequency low-loss MnZn power ferrite material.

[0033] Example 2 An ultra-high frequency low-loss MnZn power ferrite material, comprising a main component and an auxiliary component; The main components, in terms of mass percentage, include: Fe2O3 69wt%, Mn3O4 23wt%, and ZnO 8wt%; The mass content of the auxiliary components in the main components is: Tb2O3600ppm, Y2O3200ppm.

[0034] The specific preparation method is the same as that in Example 1.

[0035] Example 3 An ultra-high frequency low-loss MnZn power ferrite material, comprising a main component and an auxiliary component; The main components, in terms of mass percentage, include: Fe2O3 69wt%, Mn3O4 23wt%, and ZnO 8wt%; The mass content of the auxiliary components in the main components is: Tb2O3 200ppm, Y2O3 600ppm.

[0036] The specific preparation method is the same as that in Example 1.

[0037] Comparative Example 1 A MnZn power ferrite material comprising a main component and an auxiliary component; The main components, in terms of mass percentage, include: Fe2O3 69wt%, Mn3O4 23wt%, and ZnO 8wt%; The mass content of the auxiliary component in the main component is: Tb2O3800ppm.

[0038] The specific preparation method is the same as that in Example 1.

[0039] Comparative Example 2 A MnZn power ferrite material, the specific composition and preparation method of which are as described in Example 1, except that it does not contain auxiliary components.

[0040] Test example 1. XRD characterization and loss (P cv ) test, the results are as follows Figure 1 and as shown in Table 1.

[0041] Loss (P cv ) The specific test method is: using LCR-8210 digital bridge at 1V voltage and 1MHz to measure the initial magnetic permeability (μ) of the products prepared in Examples 1 to 3 and Comparative Examples 1 to 2. i The room temperature loss P of the products prepared in Examples 1 to 4 and Comparative Examples 1 to 2 at 1 MHz, 30 mT and 3 MHz, 10 mT was tested using a soft magnetic AC measuring instrument (MAST-3000SA). cv .

[0042] As shown in Table 1, compared with Comparative Example 2, the loss of the MnZn ferrite material prepared by adding the auxiliary components Y2O3 and Tb2O3 under 1MHz and 3MHz conditions is significantly reduced, and the initial magnetic permeability of the embodiment is also significantly improved. This shows that the preparation method provided by the present invention effectively improves the performance of the MnZn ferrite material by composite doping with the two rare earth oxides Tb2O3 and Y2O3, so that the MnZn ferrite material prepared by the present invention takes into account the characteristics of high frequency / ultra-high frequency low loss and high magnetic permeability. By comparing Examples 1 to 3 with Comparative Example 1, it can be seen that by replacing the high-cost Tb2O3 with the low-cost Y2O3, the goals of improving performance and controlling costs can be achieved simultaneously, so that the application frequency band of MnZn ferrite is expanded to the MHz level, and the added value of the product is increased at a lower cost. Among them, Example 1 is the formula with the best comprehensive performance in the experiment and can be applied to large-scale production.

[0043] The ultra-high frequency low loss MnZn power ferrite material prepared in Example 1 is modified by adding Y2O3 and Tb2O3 as auxiliary components to the MnZn ferrite. 3+ and Y 3+ ) have ionic radii larger than Fe 3+ Due to their large ionic radius, they are less likely to penetrate the crystal lattice and instead accumulate at grain boundaries, inhibiting their movement, thereby limiting grain growth and increasing the number of grain boundaries within the sample. This ultimately increases the resistivity of the MnZn ferrite material, reduces grain size, and reduces eddy current losses, thereby improving its performance at high and ultra-high frequencies (1MHz / 3MHz). Furthermore, the material exhibits a high cutoff frequency, which means that resonance is not easily excited, resulting in very low or even negligible residual losses. Consequently, the total losses of the MnZn ferrite at ultra-high frequencies are low.

[0044] Depend on Figure 1It can be seen that the samples prepared in Examples 1-3 of the present invention and Comparative Examples 1-2 have only one phase, MnZn ferrite, after XRD analysis, indicating that the preparation method provided by the present invention can successfully prepare MnZn ferrite material.

[0045] 2. The morphology of the products prepared in Examples 1 to 3 and Comparative Examples 1 to 2 was observed using a scanning electron microscope (SEM). The results are as follows: Figures 2 to 6 shown.

[0046] Depend on Figures 2 to 6 It can be seen that the grain size of the MnZn ferrite material prepared in Example 1 is significantly smaller than that in Comparative Example 1. Due to the addition of Tb2O3 and Y2O3, the grain size is smaller than that in Comparative Example 1, which helps to reduce the total loss. The addition of multiple ions changes the microscopic composition of the ferrite material and changes the electromagnetic properties of the material, which is beneficial to reducing the loss.

[0047] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify or replace the technical solutions of the present invention with equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An ultra-high frequency low-loss MnZn power ferrite material, characterized in that: Includes main components and auxiliary components; The main components are calculated by weight percentage, including: Fe2O3 68.0-69.4wt%, Mn3O4 22.8-23.8wt%, ZnO 7.6-8.0wt%, with a total amount of 100wt%; The mass content of the auxiliary components in the main components is: Y2O3 200-600ppm, Tb2O3 200-800ppm.

2. The ultra-high frequency low-loss MnZn power ferrite material according to claim 1, characterized in that: The main components are expressed in percentage by mass, including: Fe2O3 69wt%, Mn3O4 23wt%, ZnO 8wt%, with a total amount of 100wt%; The mass content of the auxiliary components in the main components is: Tb2O3400ppm, Y2O3400ppm.

3. A method for preparing the ultra-high frequency low-loss MnZn power ferrite material according to claim 1, characterized in that: The steps are as follows: (1) Weigh the main component raw materials Fe2O3, Mn3O4, and ZnO according to the ratio, perform a ball milling process, and then dry the ball milled slurry to obtain the main component powder; (2) pre-calcining the main component powder obtained in step (1), and cooling it to obtain a main component pre-calcined material; (3) According to the proportion, the main component pre-sintered material obtained in step (2) is mixed with the auxiliary component raw materials Tb2O3 and Y2O3, and a secondary ball milling treatment is performed. The ball milled slurry is then dried to obtain a mixed powder; (4) adding a polyvinyl alcohol aqueous solution to the mixed powder obtained in step (3), uniformly granulating the mixture in a mechanical granulator, and sieving the mixture to obtain granular material; (5) The granular material obtained in step (4) is pressed and sintered in sequence to obtain an ultra-high frequency low-loss MnZn power ferrite material.

4. The method according to claim 3, wherein In step (1), the primary ball milling is carried out in a ball mill for 60 to 70 minutes. During the ball milling process, the mass ratio of steel balls, raw materials and deionized water is 3:1:1, and the ball mill speed is 280 to 320 revolutions per minute. The average particle size of the main component powder is ≤1.1 μm.

5. The method according to claim 3, wherein In step (2), the pre-firing temperature is 900-1000° C., and the pre-firing time is 1.5-2.5 hours.

6. The method according to claim 3, wherein In step (3), the secondary ball milling is carried out in a ball mill, the ball milling time is 300-400 min, the mass ratio of steel balls, raw materials and deionized water during the ball milling process is 5:1:1, and the ball mill speed is 330-370 rpm; the average particle size of the mixed powder is 1-1.2 μm.

7. The method according to claim 3, wherein In step (4), the mass concentration of the polyvinyl alcohol aqueous solution is 3-5%, and the mass ratio of the polyvinyl alcohol aqueous solution to the mixed powder is (5-10):

100.

8. The method according to claim 3, wherein In step (4), the granulation time is 100-200s, and the granulation rotation speed is 5000-6000r.

9. The method according to claim 3, wherein In step (5), the pressing is to press the magnetic ring at 400 MPa; the sintering is to place the magnetic ring in a sintering device, sinter it at 1150-1200°C for 30-60 minutes, and then cool it to below 300°C; More preferably, the sintering is to sinter the magnetic ring at 1180° C. for 30 minutes.

10. Application of the ultra-high frequency low-loss MnZn power ferrite material according to claim 1 in the fields of aerospace or automotive electronics.

Images