Preparation Method of a Coated High-Dielectric Low-Loss Microwave Ferrite Material

Abstract

A preparation method of a coated high-dielectric low-loss microwave ferrite material belongs to the field of electronic materials. The coated high-dielectric low-loss microwave ferrite material of the present invention has a core of NiCuZn ferrite based on NiCuZn ferrite material, and Ir element is used for performance regulation to reduce the microwave loss of the material and obtain excellent low-loss ferrite; the outer shell is carbon spheres prepared by the hydrothermal method, which has a good dielectric constant, is coated on the outside of the ferrite, has good uniformity, and improves the dielectric constant of the material. The coated high-dielectric low-loss microwave ferrite material prepared by the present invention has a high dielectric constant (ε' = 30 - 60) and low microwave loss (ferromagnetic resonance linewidth ΔH = 120 - 180 Oe) in the microwave frequency band (9.56 GHz), meeting the application requirements of circulators, isolators, and phase shifters in the microwave frequency band.

Description

Technical Field

[0001] The present invention belongs to the field of electronic materials, and particularly relates to a preparation method of a coated high-dielectric low-loss microwave ferrite material. Background Art

[0002] With the rapid development of 5G / 6G communication, information transmission in the microwave band has gradually become one of the main ways. In a microwave transmission system, the size and performance of microwave devices directly affect the integration and transmission characteristics of the overall microwave system. Common microwave devices such as circulators, isolators, and phase shifters, the performance of these devices depends on the substrate material and circuit design. Especially the substrate material, first determines the area of the circuit design, and secondly, the performance of the substrate material directly affects the performance of the device. For example, in microwave devices, the dielectric constant of the substrate material directly affects the size of the device. This is because in microwave band applications, when electromagnetic waves propagate through a dielectric material, the wavelength is inversely proportional to the dielectric constant. This means that as the dielectric constant increases, the wavelength shortens, and thus the size of the microwave device can be reduced. Secondly, the ferromagnetic resonance linewidth of the material affects the transmission efficiency of the microwave device. A lower ferromagnetic resonance linewidth can enable the microwave device to have lower microwave losses and obtain higher transmission efficiency during application. Therefore, the design and preparation of materials with high dielectric constant and low ferromagnetic resonance linewidth are one of the main research directions of microwave device materials.

[0003] Among microwave ferrite materials, the most studied is garnet ferrite material. Garnet ferrite material is one of the excellent basic materials for microwave devices due to its excellent ferromagnetic resonance linewidth characteristics. However, while garnet ferrite materials have a lower ferromagnetic resonance linewidth, their general dielectric constant is around 14. The patent "A garnet-type microwave ferrite sheet and its preparation method" (patent number ZL202110883334.8) uses a variety of ion-modified garnet ferrite materials, and the ferromagnetic resonance linewidth ΔH is within 20, but its dielectric constant is not described. The patent "A garnet ferrite material and its preparation method and application" (patent number ZL202011565499.2) uses a variety of ion-modified garnet ferrite materials, with a dielectric constant of not less than 20 and a ferromagnetic resonance linewidth of not more than 30Oe. Although the dielectric constant has been improved, it can be further improved in terms of device miniaturization. The patent "High dielectric medium saturation magnetization garnet ferrite material and preparation method" (application number: CN202310388195.0) uses Bi, Ca, Zr, V and other elements to modify garnet ferrite materials to obtain high dielectric constant (ε=23-25) and medium saturation magnetization materials. At the same time, the ferrite ferromagnetic resonance linewidth can be lower than 300Oe, which meets the application materials of microwave devices. At the same time, the patent "High dielectric low linewidth garnet ferrite material and preparation method" (application number: 202310391039.X) uses Bi, Ca, Zr, In and other elements for ion modification, and the dielectric constant is increased to 28-30. The line width is also relatively low, which is a basic material that meets the requirements of microwave devices to reduce size and improve performance.

[0004] However, as the size of the device is further reduced, the dielectric constant needs to be further improved. Therefore, in view of the application requirements of microwave devices, the present invention adopts NiCuZn spinel ferrite, and utilizes its high saturation magnetization intensity, low cost and process stability to regulate its dielectric constant, thereby obtaining a ferrite material with a high dielectric constant and stable ferromagnetic resonance linewidth, which is conducive to the miniaturization and high performance of microwave devices. Summary of the invention

[0005] The purpose of the present invention is to propose a method for preparing a coated high-dielectric low-loss microwave ferrite material in view of the problems existing in the background technology.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a coated high-dielectric low-loss microwave ferrite material comprises the following steps:

[0008] Step 1. Using nickel oxide (NiO), copper oxide (CuO), zinc oxide (ZnO), iridium dioxide (IrO2), and iron(III) oxide (Fe2O3) as raw materials, weigh the raw materials according to the stoichiometric ratio of Ni 0.28 Cu 0.16 Zn 0.56 Fe 2-x Ir x O4, where x = 0.0 - 0.3;

[0009] Step 2. According to the process of solid-phase sintering method, prepare NiCuZn ferrite materials from the raw materials weighed in Step 1;

[0010] 2.1 Place the raw materials weighed in Step 1 into a polytetrafluoroethylene or nylon ball mill tank, use zirconia and deionized water as grinding media, conduct primary ball milling, the ball milling time is 10 - 16 hours, and the rotation speed is 200 - 280 revolutions per minute; after the ball milling is completed, take it out, dry it in a blast drying oven, and pre-sinter it at a temperature of 850 - 1000 °C in a high-temperature furnace for 1 - 6 hours;

[0011] 2.2 Conduct secondary ball milling on the pre-sintered material obtained in Step 2.1, use zirconia and deionized water as grinding media, the secondary ball milling time is 8 - 16 hours, and the rotation speed is 200 - 280 revolutions per minute; after the secondary ball milling is completed, take it out and dry it at 60 - 120 °C in a blast drying oven;

[0012] 2.3 Granulate the dried powder obtained in Step 2.2, and then sinter it at a temperature of 1000 - 1200 °C for 1 - 8 hours to obtain NiCuZn ferrite materials, grind them through a 120-mesh sample sieve for standby;

[0013] Step 3. According to the mass ratio of deionized water: glucose = 8:2, weigh glucose and dissolve it in deionized water, stir and mix evenly to prepare a glucose solution;

[0014] Step 4. Add the NiCuZn ferrite materials obtained in Step 2 with the same mass as glucose to the glucose solution obtained in Step 3, transfer the resulting mixture to a polytetrafluoroethylene reaction kettle, place the reaction kettle in a steel seal can and seal it;

[0015] Step 5. Place the sealed can in Step 4 into a constant-temperature sintering furnace or a constant-temperature drying oven, keep it at a temperature of 160 °C - 200 °C for 2 - 10 hours to prepare carbon spheres by hydrothermal reaction;

[0016] Step 6. After the reaction is completed, naturally cool it to room temperature (to prevent air pressure in the tank), open the reaction kettle, and after filtration, wash it with ethanol and deionized water to obtain the high-dielectric low-loss microwave ferrite material.

[0017] The present invention also provides an application of the above-mentioned high-dielectric low-loss microwave ferrite material as a substrate material for microwave devices (such as circulators, isolators, phase shifters, etc.).

[0018] The coated high-dielectric low-loss microwave ferrite material of the present invention has a core of NiCuZn ferrite based on NiCuZn ferrite material, and Ir element is used to regulate its performance to reduce the microwave loss of the material and obtain an excellent low-loss ferrite; the shell is carbon spheres prepared by a hydrothermal method, which has a relatively high dielectric constant and is coated on the outside of the ferrite with good uniformity, thereby enhancing the dielectric constant of the material. The prepared coated high-dielectric low-loss microwave ferrite material of the present invention has a high dielectric constant (ε' = 30 - 60) and a low microwave loss (ferromagnetic resonance linewidth ΔH = 120 - 180 Oe) in the microwave frequency band (9.56 GHz), meeting the application requirements of circulators, isolators, and phase shifters in the microwave frequency band.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] 1. The coated high-dielectric low-loss microwave ferrite material of the present invention adopts a coated structure, with a carbon sphere shell and a core of Ni 0.28 Cu 0.16 Zn 0.56 Fe 2-x Ir x O4 spinel ferrite. Through the formation of the coated structure, the dielectric constant of the material is enhanced, and the stable ferromagnetic resonance linewidth of the material is maintained, meeting the application requirements of microwave devices.

[0021] 2. The coated high-dielectric low-loss microwave ferrite material of the present invention has a high dielectric constant (ε' = 30 - 60) and a low microwave loss (ferromagnetic resonance linewidth ΔH = 120 - 180 Oe) in the microwave frequency band (9.56 GHz), meeting the application requirements of circulators, isolators, and phase shifters in the microwave frequency band.

[0022] 3. When the coated high-dielectric low-loss microwave ferrite material of the present invention is used as a substrate for microwave devices, it can well realize the miniaturization of microwave devices, and is beneficial to improving the transmission efficiency of circulators, realizing the miniaturization and high performance of microwave devices, and providing a new material for the application of high-frequency and integrated small-size microwave devices. Description of the Drawings

[0023] Figure 1 It is a flow chart of the preparation method of the coated high-dielectric low-loss microwave ferrite material of the present invention.

[0024] Figure 2 It is a micrograph of the NiCuZn ferrite prepared in Example 1 of the present invention.

[0025] Figure 3 The microscopic structure diagram and schematic diagram of the coated high-dielectric low-loss microwave ferrite material prepared in Example 1 of the present invention.

[0026] Figure 4 The XRD patterns of the coated high-dielectric low-loss microwave ferrite materials prepared in Examples 1, 2, and 3 of the present invention. Detailed implementation manners

[0027] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0028] Example 1

[0029] A preparation method of a coated high-dielectric low-loss microwave ferrite material includes the following steps:

[0030] Step 1. Using nickel oxide (NiO), copper oxide (CuO), zinc oxide (ZnO), and iron(III) oxide (Fe2O3) as raw materials, weigh 2.09 g of NiO raw material, 1.27 g of CuO raw material, 4.56 g of ZnO raw material, and 15.97 g of Fe2O3 raw material according to the stoichiometric ratio of Ni 0.28 Cu 0.16 Zn 0.56 Fe 2-x Ir x O4 (x = 0.0);

[0031] Step 2. According to the process of solid-phase sintering method, prepare the NiCuZn ferrite material from the raw materials weighed in Step 1.

[0032] 2.1 Place the raw materials weighed in Step 1 into a polytetrafluoroethylene ball-milling tank, use zirconia and deionized water as grinding media, conduct primary ball milling for 12 hours at a rotation speed of 250 revolutions per minute; after ball milling is completed, take it out, dry it in a blast drying oven, and pre-sinter it at 950 °C in a high-temperature furnace for 4 hours.

[0033] 2.2 Conduct secondary ball milling on the pre-sintered material obtained in Step 2.1, use zirconia and deionized water as grinding media, the secondary ball milling time is 12 hours, and the rotation speed is 250 revolutions per minute; after secondary ball milling is completed, take it out and dry it at 80 °C in a blast drying oven.

[0034] 2.3 Granulate the dried powder obtained in Step 2.2, then raise the temperature to 1100 °C at a heating rate of 2 °C per minute, sinter at 1100 °C for 4 hours to obtain the NiCuZn ferrite material, grind it through a 120-mesh sample sieve for later use.

[0035] Step 3. Weigh 10 g of glucose and dissolve it in 40 mL of deionized water according to the mass ratio of deionized water:glucose = 8:2, stir and mix evenly to prepare a glucose solution.

[0036] Step 4. Add 10 g of the NiCuZn ferrite material obtained in Step 2 to the glucose solution obtained in Step 3, transfer the resulting mixture to a polytetrafluoroethylene reaction kettle, place the reaction kettle in a steel seal can, and seal it.

[0037] Step 5. Place the sealed can in Step 4 into a constant-temperature sintering furnace or a constant-temperature drying oven, keep it at 190 °C for 8 hours, and prepare carbon spheres by hydrothermal reaction.

[0038] Step 6. After the reaction is completed, naturally cool it to room temperature (to prevent pressure inside the can), open the reaction kettle, and obtain the high-dielectric low-loss microwave ferrite material after filtration, washing with ethanol and deionized water.

[0039] Example 2

[0040] The difference between this example and Example 1 is that:

[0041] The process of Step 1 is adjusted to: using nickel oxide (NiO), copper oxide (CuO), zinc oxide (ZnO), iridium dioxide (IrO2) and iron(III) oxide (Fe2O3) as raw materials, according to the stoichiometric ratio of Ni 0.28 Cu 0.16 Zn 0.56 Fe 2-x Ir x O4 (x = 0.15), weigh 2.09 g of NiO raw material, 1.27 g of CuO raw material, 4.56 g of ZnO raw material, 3.36 g of IrO2 raw material, and 14.77 g of Fe2O3 raw material; the remaining steps are the same as in Example 1.

[0042] Example 3

[0043] The difference between this example and Example 1 is that:

[0044] The process of Step 1 is adjusted to: using nickel oxide (NiO), copper oxide (CuO), zinc oxide (ZnO), iridium dioxide (IrO2) and iron(III) oxide (Fe2O3) as raw materials, according to the stoichiometric ratio of Ni 0.28 Cu 0.16 Zn 0.56 Fe 2-x Ir x O4 (x = 0.3), weigh 2.09 g of NiO raw material, 1.27 g of CuO raw material, 4.56 g of ZnO raw material, 6.73 g of IrO2 raw material, and 13.57 g of Fe2O3 raw material; the remaining steps are the same as in Example 1.

[0045] Figure 2This is the micrograph of the NiCuZn ferrite prepared in Example 1 of the present invention. It can be seen from the figure that the NiCuZn ferrite material has small grains and exhibits good uniformity and dispersion.

[0046] Figure 3 This is the microstructure diagram and schematic diagram of the coated high-dielectric low-loss microwave ferrite material prepared in Example 1 of the present invention. It can be seen from the figure that the carbon spheres are well formed, and there are some small particles on the surface which are NiCuZn ferrite. The interior contains NiCuZn particles. The schematic diagram also shows that the NiCuZn material has a small size and has entered the interior of the carbon spheres.

[0047] Figure 4 This is the XRD pattern of the coated high-dielectric low-loss microwave ferrite materials prepared in Examples 1, 2, and 3 of the present invention. It can be seen from the figure that the material has the phase of carbon and the spinel phase of NiCuZn, indicating the coexistence of two phases.

[0048] The results of the ferromagnetic resonance linewidth and dielectric constant of the materials obtained in Example 1, Example 2, and Example 3 are shown in Table 1. At a microwave frequency of 9.5 GHz, the materials have a relatively low ferromagnetic resonance linewidth and a relatively high dielectric constant. According to the results, the coated high-dielectric low-loss microwave ferrite materials prepared in the examples have a high dielectric constant and a low ferromagnetic resonance linewidth coefficient, and can be used as the substrate material for microwave devices.

[0049] Table 1

[0050]

[0051]

Claims

1. A preparation method of a coated high-dielectric low-loss microwave ferrite material, characterized in that It includes the following steps: Step 1. Using NiO, CuO, ZnO, IrO2 and Fe2O3 as raw materials, weigh the raw materials according to the stoichiometric ratio of Ni 0.28 Cu 0.16 Zn 0.56 Fe 2-x Ir x O4, where x = 0.0 to 0.3; Step 2. Prepare the NiCuZn ferrite material from the raw materials weighed in Step 1 according to the process of solid-phase sintering method; 2.1 Conduct primary ball milling on the raw materials weighed in Step 1, with the ball milling time being 10 - 16 hours and the rotation speed being 200 - 280 revolutions per minute; after the ball milling is completed, take it out, dry it, and pre-sinter it at a temperature of 850 - 1000 °C for 1 - 6 hours; 2.2 Conduct secondary ball milling on the pre-sintered material obtained in Step 2.1, with the secondary ball milling time being 8 - 16 hours and the rotation speed being 200 - 280 revolutions per minute; after the secondary ball milling is completed, take it out and dry it; 2.3 Granulate the dried powder obtained in Step 2.2, and then sinter it at a temperature of 1000 - 1200 °C for 1 - 8 hours to obtain the NiCuZn ferrite material; Step 3. Weigh glucose according to the mass ratio of deionized water: glucose = 8:2, dissolve it in deionized water, stir and mix evenly to prepare a glucose solution; Step 4. Add the NiCuZn ferrite material obtained in Step 2 with the same mass as glucose to the glucose solution obtained in Step 3, transfer the resulting mixture to a reaction kettle, place the reaction kettle in a steel sealed tank, and seal it; Step 5. Place the sealed tank in Step 4 in a constant-temperature sintering furnace or a constant-temperature drying oven, and keep it at a temperature of 160 °C - 200 °C for 2 - 10 hours; Step 6. After the reaction is completed, naturally cool it to room temperature, open the reaction kettle, and obtain the high-dielectric low-loss microwave ferrite material through filtration and washing; The high-dielectric low-loss microwave ferrite material has a coated structure, with a carbon sphere as the outer shell and Ni 0.28 Cu 0.16 Zn 0.56 Fe 2-x Ir x O4 spinel ferrite.

2. Application of the high-dielectric low-loss microwave ferrite material as claimed in claim 1 as a substrate material for microwave devices.

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