Low-temperature sintered high-dielectric-constant ferrite material and preparation method thereof

Abstract

The invention provides a low-temperature sintered high-dielectric-constant ferrite material and a preparation method thereof. Wherein the chemical formula of the ferrite material is Y < 3-y > Bi < y > Fe < 5-2x > Cu < x > Zr < x > O < 12 >, x ranges from 0.2 to 1, and y ranges from 0.4 to 1.5. The ferrite material is YIG ceramic of a Cu-Zr-Bi system, Y < 3 + > ions in dodecahedron gaps in YIG crystal lattices are replaced by Bi < 3 + > ions, and Fe < 3 + > ions in octahedron gaps are preferentially replaced by Cu < 2 + > and Zr < 4 + > ions. Cu and Bi both have the effect of assisting sintering, can promote growth of crystalline grains, improve the microstructure and improve the densification level, and have positive significance on dielectric loss and dielectric properties; and non-magnetic Cu < 2 + > and Zr < 4 + > ions are substituted, so that the saturation magnetization of YIG can be improved. By introducing the Mn element additive, the ferromagnetic resonance line width of the dielectric loss of the system is further reduced.

Description

Technical Field

[0001] This application belongs to the field of materials technology. Specifically, it relates to a high dielectric constant ferrite material with low sintering temperature and a preparation method thereof. Background Art

[0002] The gyromagnetic ferrite made by utilizing the gyromagnetic properties of ferrite and the ferromagnetic resonance phenomenon is one of the most important and irreplaceable applications of ferrite materials in microwave devices. Ferrite has wide application value in various microwave devices such as phase shifters, circulators, isolators, and filters. Among them, yttrium iron garnet (YIG) is widely used in various microwave devices due to a series of advantages such as high saturation magnetization intensity, high resistivity, and small ferromagnetic resonance linewidth. However, in recent years, with the rapid development of communication technology, higher requirements have been put forward for aspects such as miniaturization, lightweight, and high frequency of devices. There is an urgent need for high-performance ferrite materials with low sintering temperature, high dielectric constant, low dielectric loss, high saturation magnetization intensity, and low ferromagnetic resonance linewidth. In recent years, some literatures and patents have reported the preparation of high dielectric constant YIG ferrites. For example, the dielectric constant of the YIG ferrite reported in the patent publication number CN112960977 has been increased to more than 18, the dielectric constant of the YIG ferrite in the patent publication number CN107417266A can reach 21, the dielectric constant of the YIG ferrite in the patent publication number CN104478425A can be increased to 26 - 28, and the dielectric constant of the YIG ferrite in the patent publication number CN119143496A can be increased to 30 - 35.

[0003] However, the current YIG ferrite materials still have many deficiencies: most of the sintering temperatures are higher than 1100°C, which cannot achieve low-temperature co-firing with silver electrodes and greatly increases the production cost; although the dielectric properties are improved, the dielectric loss and ferromagnetic resonance linewidth of the YIG ferrite materials are also increased due to doping, and the saturation magnetization intensity is also slightly reduced. The deterioration of other electromagnetic properties limits the application of YIG ferrite in device form. Summary of the Invention

[0004] Based on the problems existing in the prior art, this application provides a high dielectric constant yttrium iron garnet microwave ferrite material with low sintering temperature and a preparation method thereof, which coordinately optimizes the magnetic properties on the basis of achieving low sintering temperature and high dielectric constant.

[0005] Specifically, this application relates to the following aspects:

[0006] 1. A ferrite material, whose chemical formula is Y 3-y Bi y Fe 5-2x Cu x Zr x O 12, where x is 0.2 - 1 and y is 0.4 - 1.5.

[0007] 2. The ferrite material according to item 1, wherein x is 0.2 - 0.6.

[0008] 3. The ferrite material according to item 1 or 2, wherein y is 0.8 - 1.2.

[0009] 4. The ferrite material according to any one of items 1 - 3, wherein the ferrite material is doped with Mn element.

[0010] 5. The ferrite material according to item 4, wherein the content of Mn element is greater than 0 and less than or equal to 0.7 wt%.

[0011] 6. A method for preparing a ferrite material, comprising the following steps:

[0012] Mix Fe2O3, Y2O3, CuO, ZrO2, Bi2O3 and optionally MnO2 and perform pre - sintering;

[0013] Ball - mill and granulate the pre - sintered product to obtain pre - sintered product particles;

[0014] Sinter the pre - sintered product particles to obtain the ferrite material;

[0015] The chemical formula of the ferrite material is Y 3-y Bi y Fe 5-2x Cu x Zr x O 12 , where x is 0.2 - 1 and y is 0.4 - 1.5.

[0016] 7. The preparation method according to item 6, wherein the sintering of the pre - sintered product particles includes a first - stage sintering and a second - stage sintering, wherein the temperature of the first - stage sintering is 600 - 650 °C, the time is 0.5 - 2 hours, the temperature of the second - stage sintering is 800 - 950 °C, and the time is 0.5 - 4 hours.

[0017] 8. The preparation method according to item 6 or 7, wherein the temperature of the pre - sintering is 600 - 700 °C, and the time is 0.5 - 2 hours.

[0018] 9. The preparation method according to any one of items 6 - 8, wherein x is 0.2 - 0.6.

[0019] 10. The preparation method according to any one of items 6 - 9, wherein y is 0.8 - 1.2.

[0020] 11. The preparation method according to any one of Items 6 - 10, wherein the content of MnO2 in the raw materials is greater than 0 and less than or equal to 1 wt%.

[0021] 12. A ferrite material prepared by the preparation method according to any one of Items 6 - 11.

[0022] 13. A microwave device comprising the ferrite material according to any one of Items 1 - 5, or the ferrite material according to Item 12.

[0023] Advantages of the present application

[0024] The ferrite material of the present application is a YIG ceramic of the Cu - Zr - Bi system, where Bi 3+ ions substitute for Y ions in the dodecahedral interstitial sites of the YIG lattice, and Cu 2+ and Zr 4+ ions preferentially substitute for Fe 3+ ions in the octahedral interstitial sites. Both Cu and Bi have the function of promoting sintering, can promote the growth of grains, improve the microstructure, enhance the densification level, and are of positive significance for both dielectric loss and dielectric properties; the substitution of non - magnetic Cu 2+ and Zr 4+ ions can increase the saturation magnetization intensity of YIG. By introducing the Mn element additive, the dielectric loss and ferromagnetic resonance linewidth of the system are further reduced.

[0025] Compared with the prior art, the ferrite material of the present application has a low sintering temperature and a high dielectric constant, and other properties can also be well maintained, which can meet the requirements of co - firing at low temperature with dielectric ceramic materials, and at the same time realize the miniaturization of devices, and can be applied to various microwave magnetic devices such as circulators, isolators, and filters.

[0026] The preparation method of the ferrite material of the present application can introduce Cu and Zr elements, and can use a low sintering temperature of 800 - 950 °C to prepare a ferrite material with a high dielectric constant and saturation magnetization intensity, thus saving energy consumption. In addition, a high dielectric constant is beneficial to the requirements of miniaturization and light weight of ferrite devices, and low - temperature co - firing is also beneficial to future integration. Detailed implementation manners

[0027] The present application will be further described below with reference to embodiments. It should be understood that the embodiments are only used to further illustrate and explain the present application, and are not used to limit the present application.

[0028] Unless otherwise defined, the technical and scientific terms used in this specification have the same meanings as those commonly understood by those skilled in the art. Although methods and materials similar or equivalent to those described herein can be used in experiments or practical applications, the materials and methods are described hereinafter. In case of conflict, the present specification, including its definitions, shall prevail. Additionally, the materials, methods, and examples are for illustrative purposes only and not limiting. The present application will be further described below in conjunction with specific embodiments, but it is not intended to limit the scope of the present application.

[0029] As described above, there are still many deficiencies in the current YIG ferrite materials: most of the sintering temperatures are higher than 1100 °C, which makes it impossible to achieve low-temperature co-firing with silver electrodes and greatly increases the production cost; although the dielectric properties are improved, the dielectric loss and ferromagnetic resonance linewidth of the YIG ferrite materials are also increased due to doping, and the saturation magnetization intensity is slightly reduced. The deterioration of other electromagnetic properties limits the application of YIG ferrite devices.

[0030] In view of the problems existing in the prior art, the present application provides a ferrite material with the chemical formula Y 3-y Bi y Fe 5- 2x Cu x Zr x O 12 , where x is 0.2 - 1 and y is 0.4 - 1.5.

[0031] x is 0.2 - 1, for example, it can be 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, and any value between these values.

[0032] In some embodiments, x is 0.2 - 0.6.

[0033] y is 0.4 - 1.5, for example, it can be 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, and any value between these values.

[0034] In some embodiments, y is 0.8 - 1.2.

[0035] In some embodiments, x is 0.2 - 0.6 and y is 0.8 - 1.2.

[0036] Furthermore, the ferrite material may be doped with Mn element.

[0037] In some embodiments, the content of Mn element in the ferrite material is greater than 0 and less than or equal to 0.7 wt%, for example, it can be 0.01 wt%, 0.05 wt%, 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.35 wt%, 0.4 wt%, 0.45 wt%, 0.5 wt%, 0.55 wt%, 0.6 wt%, 0.65 wt%, 0.7 wt%, and any value between these values.

[0038] The content of each element in the ferrite material can be detected by methods known in the art. For example, XPS can be used for detection.

[0039] The ferrite material of the present application is a YIG ceramic of the Cu-Zr-Bi system, in which Bi 3+ ions replace Y in the dodecahedral interstitial sites of the YIG lattice 3+ ions, and Cu 2+ and Zr 4+ ions preferentially replace Fe in the octahedral interstitial sites 3+ ions. Both Cu and Bi have the function of promoting sintering, which can promote the growth of grains, improve the microstructure, and increase the densification level, and are of positive significance for both dielectric loss and dielectric properties; the substitution of non-magnetic Cu 2+ and Zr 4+ ions can increase the saturation magnetization intensity of YIG. Further, by introducing the Mn element additive, the ferromagnetic resonance linewidth of the dielectric loss of the system can be further reduced.

[0040] The present application also provides a preparation method of a ferrite material, including the following steps:

[0041] Step S1: Mix Fe2O3, Y2O3, CuO, ZrO2, Bi2O3 and optionally MnO2 and perform pre-sintering;

[0042] Step S2: Ball-mill and granulate the pre-sintered product to obtain pre-sintered product particles;

[0043] Step S3: Sinter the pre-sintered product particles to obtain a ferrite material;

[0044] The chemical formula of the ferrite material is Y 3-y Bi y Fe 5-2x Cu x Zr x O 12 , where x is 0.2 - 1 and y is 0.4 - 1.5.

[0045] In step S1, according to the chemical formula of the ferrite material Y 3-y Bi y Fe 5-2x Cu x Zr x O 12 , weigh the raw materials Fe2O3, Y2O3, CuO, ZrO2, Bi2O3 according to the stoichiometric ratio. Among them, MnO2 can be optional. When the ferrite material is not doped with Mn, MnO2 does not need to be added in step S1.

[0046] Y 3-y Bi y Fe 5-2x Cu x Zr x O 12 , where x is 0.2 - 1, for example, it can be 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, and any value between these values; y is 0.4 - 1.5, for example, it can be 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, and any value between these values.

[0047] In some embodiments, x is 0.2 - 0.6. In some embodiments, y is 0.8 - 1.2. In some embodiments, x is 0.2 - 0.6 and y is 0.8 - 1.2.

[0048] When the ferrite material is doped with Mn, then MnO2 needs to be added. In some embodiments, the content of MnO2 in the raw materials is greater than 0 and less than or equal to 1 wt%, for example, it can be 0.01 wt%, 0.05 wt%, 0.01 wt%, 0.05 wt%, 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.35 wt%, 0.4 wt%, 0.45 wt%, 0.5 wt%, 0.55 wt%, 0.6 wt%, 0.65 wt%, 0.7 wt%, 0.75 wt%, 0.8 wt%, 0.85 wt%, 0.9 wt%, 0.95 wt%, 1 wt%, and any value between these values.

[0049] The pre-sintering is carried out in an air atmosphere, specifically in a muffle furnace. The pre-sintering can improve the stability of the sintered structure, enhance the sintering activity of the raw materials, making it easier to achieve densification during the final sintering process, thereby improving the quality and performance of the product.

[0050] In some embodiments, the temperature of the pre-sintering is 600 - 700 °C, for example, it can be 600 °C, 605 °C, 610 °C, 615 °C, 620 °C, 625 °C, 630 °C, 635 °C, 640 °C, 645 °C, 650 °C, 655 °C, 660 °C, 665 °C, 670 °C, 675 °C, 680 °C, 685 °C, 690 °C, 695 °C, 700 °C, and any value between these values; the time is 0.5 - 2 hours, for example, it can be 0.5 hours, 0.6 hours, 0.7 hours, 0.8 hours, 0.9 hours, 1 hour, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours, 2 hours, and any value between these values.

[0051] Step S2 can be carried out by using methods and equipment known in the art.

[0052] The sintering in step S3 can include a first-stage sintering and a second-stage sintering. The temperature of the first-stage sintering is 600 - 650 °C, for example, it can be 600 °C, 605 °C, 610 °C, 615 °C, 620 °C, 625 °C, 630 °C, 635 °C, 640 °C, 645 °C, 650 °C, and any value between these values; the time is 0.5 - 2 hours, for example, it can be 0.5 hours, 0.6 hours, 0.7 hours, 0.8 hours, 0.9 hours, 1 hour, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours, 2 hours, and any value between these values. The first-stage sintering is used to fully remove the moisture and organic matter in the particles.

[0053] The temperature of the second-stage sintering is 800 - 950 °C, for example, it can be 800 °C, 805 °C, 810 °C, 815 °C, 820 °C, 825 °C, 830 °C, 835 °C, 840 °C, 845 °C, 850 °C, 855 °C, 860 °C, 865 °C, 870 °C, 875 °C, 880 °C, 885 °C, 890 °C, 895 °C, 900 °C, 910 °C, 915 °C, 920 °C, 925 °C, 930 °C, 935 °C, 940 °C, 945 °C, 950 °C, and any value between these values; the time is 0.5 - 4 hours, for example, it can be 0.5 hours, 0.6 hours, 0.7 hours, 0.8 hours, 0.9 hours, 1 hour, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours, 2 hours, 2.1 hours, 2.2 hours, 2.3 hours, 2.4 hours, 2.5 hours, 2.6 hours, 2.7 hours, 2.8 hours, 2.9 hours, 3 hours, 3.1 hours, 3.2 hours, 3.3 hours, 3.4 hours, 3.5 hours, 3.6 hours, 3.7 hours, 3.8 hours, 3.9 hours, 4 hours, and any value between these values.

[0054] In some embodiments, the temperature of the second-stage sintering is 850 - 900 °C and the time is 0.5 - 4 hours.

[0055] In some embodiments, the method for preparing the ferrite material includes the following steps: Step S1: Mix Fe2O3, Y2O3, CuO, ZrO2, and Bi2O3 and perform pre-sintering; the temperature of the pre-sintering is 600 - 700 °C and the time is 0.5 - 2 hours; Step S2: Ball-mill and granulate the pre-sintered product to obtain pre-sintered product particles; Step S3: Sinter the pre-sintered product particles to obtain the ferrite material; the sintering of the pre-sintered product particles includes a first-stage sintering and a second-stage sintering, wherein the temperature of the first-stage sintering is 600 - 650 °C and the time is 0.5 - 2 hours, and the temperature of the second-stage sintering is 800 - 950 °C and the time is 0.5 - 4 hours; the chemical formula of the ferrite material is Y 3-y Bi y Fe 5-2x Cu x Zr x O 12 , where x is 0.2 - 1 and y is 0.4 - 1.5.

[0056] In some embodiments, a method for preparing a ferrite material includes the following steps: Step S1: Mix Fe2O3, Y2O3, CuO, ZrO2, and Bi2O3 and perform pre-sintering; the temperature of the pre-sintering is 600 - 700 °C, and the time is 0.5 - 2 hours; Step S2: Ball-mill and granulate the pre-sintered product to obtain pre-sintered product particles; Step S3: Sinter the pre-sintered product particles to obtain the ferrite material; the sintering of the pre-sintered product particles includes a first-stage sintering and a second-stage sintering, where the temperature of the first-stage sintering is 600 - 650 °C, the time is 0.5 - 2 hours, and the temperature of the second-stage sintering is 850 - 900 °C, the time is 0.5 - 4 hours; the chemical formula of the ferrite material is Y 3-y Bi y Fe 5-2x Cu x Zr x O 12 , where x is 0.2 - 0.6, and y is 0.8 - 1.2.

[0057] In some embodiments, a method for preparing a ferrite material includes the following steps: Step S1: Mix Fe2O3, Y2O3, CuO, ZrO2, Bi2O3, and MnO2 and perform pre-sintering; the temperature of the pre-sintering is 600 - 700 °C, the time is 0.5 - 2 hours, and the content of MnO2 in the raw materials is greater than 0 and less than or equal to 1 wt%; Step S2: Ball-mill and granulate the pre-sintered product to obtain pre-sintered product particles; Step S3: Sinter the pre-sintered product particles to obtain the ferrite material; the sintering of the pre-sintered product particles includes a first-stage sintering and a second-stage sintering, where the temperature of the first-stage sintering is 600 - 650 °C, the time is 0.5 - 2 hours, and the temperature of the second-stage sintering is 800 - 950 °C, the time is 0.5 - 4 hours; the chemical formula of the ferrite material is Y 3-y Bi y Fe 5-2x Cu x Zr x O 12 , where x is 0.2 - 1, and y is 0.4 - 1.5.

[0058] In some embodiments, a method for preparing a ferrite material includes the following steps: Step S1: Mix Fe2O3, Y2O3, CuO, ZrO2, Bi2O3, and MnO2 and perform pre-sintering; the temperature of the pre-sintering is 600 - 700 °C, the time is 0.5 - 2 hours, and the content of MnO2 in the raw materials is greater than 0 and less than or equal to 1 wt%; the temperature of the pre-sintering is 600 - 700 °C, the time is 0.5 - 2 hours; Step S2: Ball-mill and granulate the pre-sintered product to obtain pre-sintered product particles; Step S3: Sinter the pre-sintered product particles to obtain a ferrite material; the sintering of the pre-sintered product particles includes a first-stage sintering and a second-stage sintering, wherein the temperature of the first-stage sintering is 600 - 650 °C, the time is 0.5 - 2 hours, and the temperature of the second-stage sintering is 850 - 900 °C, the time is 0.5 - 4 hours; the chemical formula of the ferrite material is Y 3-y Bi y Fe 5-2x Cu x Zr x O 12 , where x is 0.2 - 0.6 and y is 0.8 - 1.2.

[0059] By introducing Cu and Zr elements, the method for preparing the ferrite material of the present application can use a low sintering temperature of 800 - 950 °C to prepare a ferrite material with high dielectric constant and saturation magnetization intensity, thereby saving energy consumption.

[0060] The present application also provides a ferrite material obtained by the above preparation method.

[0061] The present application also provides a microwave device including the above ferrite material.

[0062] The ferrite material of the present application has a low sintering temperature and a high dielectric constant, and other magnetic properties can also be well maintained, which can meet the requirements of co-firing with dielectric ceramic materials at low temperature, and at the same time realize the miniaturization of devices, and can be applied to various microwave devices such as circulators, isolators, and filters.

[0063] Examples

[0064] Example 1

[0065] Use Fe2O3, Y2O3, CuO, ZrO2, Bi2O3 with a purity of 99.99% as raw materials. Set 4 groups of samples, respectively according to Y2BiFe 5-2x Cu x Zr x O 12(x = 0, 0.2, 0.4, 0.6 respectively), weigh Fe2O3, Y2O3, CuO, ZrO2, Bi2O3 according to the stoichiometric ratio to obtain 30 g of raw materials. Mix with absolute ethanol and ball-mill, dry the mixture and pre-sinter in a muffle furnace in an air atmosphere at 650 °C for 2 hours, then continue to ball-mill for 16 hours and dry, and then granulate using polyvinyl butyral (PVB, 12 wt%). In the following 4 experimental groups, the formed samples are first sintered in the same furnace at 650 °C for 2 hours, and then sintered in an air atmosphere at 800 °C, 850 °C, 950 °C, and 1000 °C for 4 hours respectively to obtain the final samples. The chemical formulas of each group of samples are respectively recorded as Y2BiFe 5-2x Cu x Zr x O 12 (x = 0, 0.2, 0.4, 0.6 respectively).

[0066] Test the dielectric properties, saturation magnetization and ferromagnetic resonance linewidth of the obtained samples.

[0067] Among them, the dielectric properties are tested using a precision impedance analyzer; the saturation magnetization is measured using a vibrating sample magnetometer (VSM), and the applied magnetic field is selected as ±5000 oe; the ferromagnetic resonance linewidth is tested using a PPMS low-temperature magnetic field measurement system, the external magnetic field frequency is 10.5 GHz, and the test range is 2000 - 4000 oe. The same test method is also used in Example 2 and Comparative Example 1.

[0068] The test data of the dielectric constant, dielectric loss, saturation magnetization, and 10.5 GHz ferromagnetic resonance linewidth of the obtained samples at 10 MHz are shown in Table 1.

[0069] Table 1 Properties of the Y2BiFe 5-2x Cu x Zr x O 12 Doping system

[0070]

[0071] Example 2

[0072] Use Fe2O3, Y2O3, CuO, ZrO2, Bi2O3 with a purity of 99.99% as raw materials. Set up 3 groups of samples, and respectively according to Y2BiFe 5-2x Cu x Zr x O 12(When \(x = 0.2\) respectively), weigh \(Fe_2O_3\), \(Y_2O_3\), \(CuO\), \(ZrO_2\), \(Bi_2O_3\) according to the stoichiometric ratio to obtain 30 g of raw materials, and add \(MnO_2\) with mass fractions of 0 wt%, 0.5 wt%, and 1 wt% respectively. Mix with absolute ethanol and ball-mill, dry the mixture, and pre-sinter in a muffle furnace at 650 °C in an air atmosphere for 2 hours. Then continue to ball-mill for 16 h and dry, and then granulate using polyvinyl butyral (PVB, 12 wt%). Finally, sinter the formed samples in the same furnace, first hold at 650 °C for 2 hours, and then sinter in an air atmosphere at 900 °C for 4 hours to obtain the final samples, and the chemical formula of the samples is denoted as \(Y_2BiFe\). 5- 2x Cu x Zr x O 12 (\(x = 0.2\)).

[0073] The measured data of the dielectric constant, dielectric loss, saturation magnetization, and ferromagnetic resonance line width at 10.5 GHz of the obtained samples at 10 MHz are shown in Table 2.

[0074] Table 2 Properties of different Mn-doped \(Y_2BiFe\) sintered at 900 °C in air atmosphere 4.6 Cu 0.2 Zr 0.2 O 12 Properties of the doping system

[0075]

[0076] Comparative Example 1

[0077] Use \(Fe_2O_3\), \(Y_2O_3\), \(Bi_2O_3\) with a purity of 99.99% as raw materials. Set 6 groups of samples, and respectively according to \(Y\) 3- y Bi y Fe_5O 12 (When \(y = 0, 0.4, 0.8, 1, 1.2, 1.5\) respectively), weigh \(Fe_2O_3\), \(Y_2O_3\), \(Bi_2O_3\) according to the stoichiometric ratio to obtain 30 g of raw materials. Mix with absolute ethanol and ball-mill, dry the mixture, and pre-sinter in a muffle furnace at 650 °C in an air atmosphere for 2 hours. Then continue to ball-mill for 16 hours and dry, and then granulate and form using polyvinyl butyral (PVB, 12 wt%). Sinter the formed samples in the same furnace, first hold at 650 °C for 2 hours, and then sinter the formed samples in the same furnace at 1400 °C in an air atmosphere for 4 hours to obtain the final samples, and the chemical formula of each group of samples is denoted as \(Y\) 3-y Bi y Fe_5O 12 (When \(y = 0, 0.4, 0.8, 1, 1.2, 1.5\) respectively).

[0078] The test data of the dielectric constant, saturation magnetization, and ferromagnetic resonance linewidth at 10.5 GHz of the obtained samples at 10 MHz are shown in Table 3.

[0079] Table 3. Y 3-y Bi y Fe5O 12 Performance of the doping system

[0080]

[0081]

[0082] The above results show that when only Bi is doped and Cu and Zr elements are not doped, the dielectric constant of the system is mostly lower than 22, the saturation magnetization is relatively low, and the ferromagnetic resonance linewidth is relatively high, which cannot meet the performance requirements of this application for the system.

[0083] For the ferrite material of this application, the dielectric constant at room temperature is 22 - 29, the dielectric loss is of the order of 10 -3 magnitude, the saturation magnetization is 1600 - 2000 G, the ferromagnetic resonance linewidth ΔH is controlled within 100 - 200 Oe, and it has a low sintering temperature of 800 - 950 °C, with excellent electromagnetic performance, which can meet the requirements of miniaturization and high frequency of various microwave devices such as phase shifters, circulators, isolators, and filters, and cost factors are taken into account.

Claims

1. A ferrite material with the chemical formula Y 3-y Bi y Fe 5-2x Cu x Zr x O 12 , where x is 0.2 - 1, preferably 0.2 - 0.6, and y is 0.4 - 1.5, preferably 0.8 - 1.

2.

2. The ferrite material according to claim 1, wherein the ferrite material is doped with Mn element. Preferably, the content of Mn element is greater than 0 and less than or equal to 0.7 wt%.

3. A method for preparing a ferrite material, comprising the following steps: Mixing Fe2O3, Y2O3, CuO, ZrO2, Bi2O3 and optionally MnO2 and performing pre-sintering; Ball-milling and granulating the pre-sintered product to obtain pre-sintered product particles; Sintering the pre-sintered product particles to obtain a ferrite material; The chemical formula of the ferrite material is Y 3-y Bi y Fe 5-2x Cu x Zr x O 12 , where x is 0.2 - 1 and y is 0.4 - 1.

5.

4. The preparation method according to claim 3, wherein the sintering of the pre-sintered product particles includes a first-stage sintering and a second-stage sintering. The temperature of the first-stage sintering is 600-650 °C and the time is 0.5-2 hours. The temperature of the second-stage sintering is 800-950 °C and the time is 0.5-4 hours.

5. The preparation method according to claim 3 or 4, wherein the temperature of the pre-sintering is 600-700 °C and the time is 0.5-2 hours.

6. The preparation method according to any one of claims 3-5, wherein x is 0.2-0.

6.

7. The preparation method according to any one of claims 3-6, wherein y is 0.8-1.

2.

8. The preparation method according to any one of claims 3-7, wherein the content of MnO2 in the raw materials is greater than 0 and less than or equal to 1 wt%.

9. A ferrite material prepared by the preparation method according to any one of claims 3-8.

10. A microwave device comprising the ferrite material according to claim 1 or 2, or the ferrite material according to claim 9.

Images