Self-biased hexagonal ferrite gyromagnetic material and preparation method thereof

Abstract

The invention provides a self-biased hexagonal ferrite gyromagnetic material and a preparation method thereof, the material is a lanthanum and manganese doped uniaxial M-type hexagonal strontium ferrite material, the structural formula is Sr0. 8La0. 2Fe1. 8Mn0. 2O19, and the additive formula comprises CuO, SiO2 and Bi2O3. The invention also provides a preparation method of the self-biased hexagonal ferrite gyromagnetic material. In secondary ball milling, CuO, SiO2 and Bi2O3 are added into a ball milling tank according to an orthogonal test design table, results are sorted through a range analysis method, a formula with the highest remanence ratio in theory is obtained, verification is carried out through verification embodiments, and the uniaxial hexagonal ferrite material with the high remanence ratio, the high magnetocrystalline anisotropy field and the relatively high density is prepared. The self-biased circulator has a wide prospect in the field of application of the self-biased circulator.

Description

Technical Field

[0001] The present invention belongs to the technical field of ferrite gyromagnetic materials, and in particular to a self-biased hexagonal ferrite gyromagnetic material and a preparation method thereof. Background Art

[0002] In a microwave communication system, as a key non-reciprocal device, the performance of a circulator directly affects the signal isolation and transmission efficiency of the system. Traditional circulators mostly use garnet ferrite. However, as the operating frequency extends to the millimeter-wave band, such materials gradually expose defects such as high high-frequency loss and insufficient temperature stability. In recent years, hexagonal ferrite has attracted much attention due to its unique magnetocrystalline anisotropy, and its relatively high natural resonance frequency provides new possibilities for solving high-frequency application problems. However, when existing hexagonal ferrite materials are applied to circulators, they still face technical bottlenecks such as the difficulty of balancing the saturation magnetization intensity and the anisotropy field, and the too wide ferromagnetic resonance linewidth, resulting in an increase in the insertion loss of the device and a limited operating bandwidth. Therefore, developing a new type of hexagonal ferrite material with high magnetocrystalline anisotropy field, high remanence ratio and low loss characteristics has become a key technical topic for improving the performance of millimeter-wave circulators.

[0003] Magnetoplumbite-type hexagonal ferrite materials are divided into six types, namely M, W, X, Y, Z and U types, according to the stacking order of their basic units. Among them, the M type has high magnetocrystalline anisotropy, a relatively simple lattice structure, and better phase formation stability, ensuring that the device will not deteriorate in performance due to approaching the natural resonance frequency during high-frequency operation. Moreover, the M-type hexagonal ferrite with high remanence ratio and coercivity after orientation ensures that the circulator can still maintain sufficient operating magnetic field strength after removing the external magnetic field, which is particularly suitable for application scenarios such as 5G / 6G communication base stations and satellite communication terminals that have strict requirements for both operating frequency and space limitations.

[0004] The current research topic of M-type hexahedrons is how to improve the remanence ratio, coercivity and magnetocrystalline anisotropy constant of M-type circulators. In the existing technology, although the magnetic properties of hexagonal ferrites have been optimized to a certain extent by means such as ion doping, it is often difficult to simultaneously meet the comprehensive requirements of high-frequency applications for the saturation magnetization intensity, anisotropy field and remanence ratio characteristics of materials. Especially in the millimeter-wave band, the high-frequency magnetic loss mechanism of materials is more complex, and the effect of traditional single-variable performance regulation methods is limited. In addition, with the increasing demand for device miniaturization and integration in application scenarios such as 5G communication and satellite communication, more stringent performance indicators are put forward for ferrite materials used in circulators. At present, a solution capable of multi-factor regulation is urgently needed to promote the further development of millimeter-wave circulator technology.

[0005] Orthogonal experiment method, with its core characteristics of balanced dispersion and neat comparability, demonstrates unique advantages in the field of material research and development. Through a carefully designed orthogonal table, this method can systematically investigate the comprehensive effects of multiple factors and multiple levels with the least number of experiments, saving more than 90% of the R & D costs compared to full-scale experiments. Its scientific data analysis method can not only accurately evaluate the main effects of various factors but also identify key interaction effects, making it particularly suitable for complex systems such as hexagonal ferrites that require optimizing multiple components and process parameters. Practice has shown that when using the orthogonal experiment method to optimize ferrite materials, the critical process window can usually be locked within 10% - 20% of the original experimental volume, fully reflecting the excellent value of this method in balancing R & D efficiency and result reliability. In this experiment, the orthogonal experiment method was used to explore and study the comprehensive additive formula to achieve the best magnetic parameters. Summary of the Invention

[0006] To achieve the above-mentioned invention objectives, the technical solution of the present invention is as follows:

[0007] A self-biased hexagonal ferrite gyromagnetic material, which is a uniaxial M-type hexagonal strontium ferrite material doped with lanthanum and manganese, and its structural formula is Sr 0.8 La 0.2 Fe 11.8 Mn 0.2 O 19 , and the additive formula includes: CuO, SiO2, Bi2O3. Calculated by weight percentage wt%, the additives include CuO accounting for (0.1 - 0.7)% of the ferrite material, SiO2 accounting for (0.1 - 0.8)%, and Bi2O3 accounting for (0.1 - 0.6)%.

[0008] As a preferred mode, the weight percentage wt% of the additives in the ferrite material is specifically as follows in the table:

[0009] Weight percentage (wt%) of additives in the ferrite material

[0010] Number CuO <![CDATA[SiO2]]> <![CDATA[Bi2O3]]> 1 0.1％ 0.1％ 0.1％ 2 0.1％ 0.3％ 0.2％ 3 0.1％ 0.6％ 0.4％ 4 0.1％ 0.8％ 0.6％ 5 0.3％ 0.1％ 0.2％ 6 0.3％ 0.3％ 0.4％ 7 0.3％ 0.6％ 0.6％ 8 0.3％ 0.8％ 0.1％ 9 0.5％ 0.1％ 0.4％ 10 0.5％ 0.3％ 0.6％ 11 0.5％ 0.6％ 0.1％ 12 0.5％ 0.8％ 0.2％ 13 0.7％ 0.1％ 0.6％ 14 0.7％ 0.3％ 0.1％ 15 0.7％ 0.6％ 0.2％ 16 0.7％ 0.8％ 0.4％ 17 0.1％ 0.6％ 0.2％ .

[0011] As a preferred mode, calculated by weight percentage wt%, the additives are CuO accounting for 0.1% of the ferrite material, SiO2 accounting for 0.6%, and Bi2O3 accounting for 0.2%.

[0012] As a preferred mode, the magnetocrystalline anisotropy field of the gyromagnetic material is 9987 - 11760 Oe, the remanence ratio reaches up to 87%, and the highest density reaches 5.058 g / cm 3 .

[0013] The second objective of the present invention is to provide a preparation method for the above-mentioned self-biased hexagonal ferrite gyromagnetic material, including the following steps:

[0014] Step 1: Weigh the raw materials; according to the ratio of ball: material: water = 6:1:1, where the zirconia balls are configured according to the diameter Ф12:Ф6:Ф3 = 1:2:3, and the primary ball milling time and rotation speed are 720 min and 300 r / min respectively to obtain a slurry; 0.8 La 0.2 Fe 11.8 Mn 0.2 O 19 Step 2: Dry and screen the slurry obtained in Step 1, and pre-burn it at a temperature of 1225 °C for 6 h to obtain a pre-burned material;

[0015] Step 3: Add additives CuO, SiO2 and Bi2O3 to the Sr

[0016] La 0.8 Fe 0.2 Mn 11.8 O 0.2 pre-burned material obtained in Step 2, and perform secondary ball milling. The ball-to-material ratio, time and rotation speed of the ball milling are the same as those of the primary ball milling. After filtering out the zirconia balls, a slurry is obtained; 19 Step 4: Control the water content of the slurry obtained in Step 3 to be 30% - 35%, and perform wet magnetic field orientation molding under an external magnetic field strength of 10 KOe and a pressure of 35 Mpa to obtain a formed green body;

[0017] Step 5: Sinter the formed green body obtained in Step 4 at a temperature of 1200 °C for 6 h to obtain the final self-biased hexagonal ferrite gyromagnetic material.

[0018] As a preferred method, in Step 3, the weight percentages wt% of the added CuO, SiO2 and Bi2O3 in the pre-burned material are specifically as follows in the following table:

[0019] The weight percentage (wt%) of the additive in the ferrite material

[0020] The M-type strontium ferrite material provided by the present invention has been detected to have a relatively high remanence ratio, and the highest remanence ratio reaches 91.56%; the high magnetocrystalline anisotropy field reaches 11760 Oe at most, and the magnetocrystalline anisotropy field can be adjusted by changing the additive content.

[0021] Number CuO <![CDATA[SiO2]]> <![CDATA[Bi2O3]]> 1 0.1％ 0.1％ 0.1％ 2 0.1％ 0.3％ 0.2％ 3 0.1％ 0.6％ 0.4％ 4 0.1％ 0.8％ 0.6％ 5 0.3％ 0.1％ 0.2％ 6 0.3％ 0.3％ 0.4％ 7 0.3％ 0.6％ 0.6％ 8 0.3％ 0.8％ 0.1％ 9 0.5％ 0.1％ 0.4％ 10 0.5％ 0.3％ 0.6％ 11 0.5％ 0.6％ 0.1％ 12 0.5％ 0.8％ 0.2％ 13 0.7％ 0.1％ 0.6％ 14 0.7％ 0.3％ 0.1％ 15 0.7％ 0.6％ 0.2％ 16 0.7％ 0.8％ 0.4％ 17 0.1％ 0.6％ 0.2％ .

[0022] The surface of the M-type strontium ferrite material was observed by scanning electron microscope SEM as

[0023] Figure 2 ​As shown, it can be seen that the grains of the M-type strontium ferrite material prepared by the present invention have obvious hexagonal flake characteristics, and the grains are relatively uniform.

[0024] Compared with the prior art, the present invention has the following characteristics:

[0025] 1. The present invention proposes a uniaxial magnetocrystalline anisotropy M-type hexagonal ferrite Sr 0.8 La 0.2 Fe 11.8 Mn 0.2 O 19 with a stable structure.

[0026] 2. During the process of adding secondary additives in the present invention, additives are added according to the orthogonal test table (x wt% CuO, y wt% SiO2, and z wt% Bi2O3, 0.1 ≤ x ≤ 0.7, 0.1 ≤ y ≤ 0.8, 0.1 ≤ z ≤ 0.6), so that the magnetic parameters of the material can be adjusted, ensuring the application range of the material.

[0027] 3. A uniaxial M-type hexagonal strontium ferrite material with rare earth and transition metal ions substituted and having adjustable saturation magnetization intensity and magnetocrystalline anisotropy field is proposed. By adjusting the proportions of CuO, SiO2, and Bi2O3 additives, a uniaxial hexagonal ferrite material with high remanence ratio, high magnetic hysteresis loop rectangularity ratio, high magnetocrystalline anisotropy field, and high density, which is highly oriented along the easy axis and has orderly adjustable magnetic parameters, has broad prospects in the application field of self-biased circulators. Description of the Drawings

[0028] Figure 1 is a flow chart of the preparation method of the high-remanence ratio and high-magnetocrystalline anisotropy self-biased hexagonal ferrite gyromagnetic material in the present invention.

[0029] Figure 2 is the microscopic morphology diagram of the self-biased hexagonal ferrite gyromagnetic material of the present invention. Among them, (a) is Example 1, (b) is Example 2, (c) is Example 3, (d) is Example 4, (e) is Example 5, (f) is Example 6, (g) is Example 7, (h) is Example 8, (i) is Example 9, (j) is Example 10, (k) is Example 11, (l) is Example 12, (m) is Example 13, (n) is Example 14, (o) is Example 15, and (p) is Example 16.

[0030] Figure 3 is the influence trend of CuO, SiO2, and Bi2O3 on the remanence ratio after the range analysis of Examples 1-16. (a) CuO; (b) SiO2; (c) Bi2O3; (d) R intuitive diagram

[0031] Figure 4 After the range analysis of Examples 1-16, the influence trends of CuO, SiO2, and Bi2O3 on the magnetocrystalline anisotropy field are shown. (a) CuO; (b) SiO2; (c) Bi2O3; (d) R intuitive diagram

[0032] Figure 5 It is the hysteresis loop of Example 17. Detailed implementation manners

[0033] The following describes the implementation manners of the present invention through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0034] The example provides a self-biased hexagonal ferrite gyromagnetic material, which is a uniaxial M-type hexagonal strontium ferrite material doped with lanthanum and manganese, and its chemical formula is Sr 0.8 La 0.2 Fe 11.8 Mn 0.2 O 19 The additive formula includes: CuO, SiO2, Bi2O3. Calculated by weight percentage wt%, the additives include (0.1-0.7)% of CuO, (0.1-0.8)% of SiO2, and (0.1-0.6)% of Bi2O3 in the ferrite material.

[0035] As a preferred mode, calculated by weight percentage wt%, the additives are 0.1% of CuO, 0.6% of SiO2, and 0.2% of Bi2O3 in the ferrite material.

[0036] As a preferred mode, the magnetocrystalline anisotropy field of the gyromagnetic material is 9987-11760 Oe, the remanence ratio reaches up to 87%, and the highest density reaches 5.058 g / cm 3 .

[0037] The remanence ratio of the material reaches up to 87%, and the highest magnetocrystalline anisotropy field reaches 11760 Oe.

[0038] Examples 1-16

[0039] The preparation method of the self-biased hexagonal ferrite gyromagnetic material includes the following steps:

[0040] Step 1: According to the chemical formula Sr 0.8 La 0.2 Fe 11.8 Mn 0.2 O 19Weigh the raw materials; according to the ratio of ball: material: water = 6:1:1, where the zirconia balls are configured according to the diameter Ф12:Ф6:Ф3 = 1:2:3, and the primary ball milling time and rotation speed are 720 min and 300 r / min respectively to obtain a slurry;

[0041] Step 2: Dry and screen the slurry obtained in Step 1, and pre-burn it at a temperature of 1225 °C for 6 h to obtain a pre-burned material;

[0042] Step 3: Add the Sr 0.8 La 0.2 Fe 11.8 Mn 0.2 O 19 Add the additives CuO, SiO2, and Bi2O3 to the pre-burned material, perform secondary ball milling, and the ball-to-material ratio, time, and rotation speed are the same as those of the primary ball milling. After filtering out the zirconia balls, a slurry is obtained;

[0043] In Step 3, the weight percentages wt% of the added CuO, SiO2, and Bi2O3 in the pre-burned material are specifically as follows in the table:

[0044] Table 1 Injection amounts of additives wt% in Examples 1-16 (orthogonal test table)

[0045] Example CuO (wt%) <![CDATA[SiO2 (wt%)]]> <![CDATA[Bi2O3 (wt%)]]> 1 0.1％ 0.1％ 0.1％ 2 0.1％ 0.3％ 0.2％ 3 0.1％ 0.6％ 0.4％ 4 0.1％ 0.8％ 0.6％ 5 0.3％ 0.1％ 0.2％ 6 0.3％ 0.3％ 0.4％ 7 0.3％ 0.6％ 0.6％ 8 0.3％ 0.8％ 0.1％ 9 0.5％ 0.1％ 0.4％ 10 0.5％ 0.3％ 0.6％ 11 0.5％ 0.6％ 0.1％ 12 0.5％ 0.8％ 0.2％ 13 0.7％ 0.1％ 0.6％ 14 0.7％ 0.3％ 0.1％ 15 0.7％ 0.6％ 0.2％ 16 0.7％ 0.8％ 0.4％

[0046] Step 4: Control the water content of the slurry obtained in Step 3 to be 30% - 35%, and perform wet magnetic field orientation molding under an external magnetic field strength of 10 KOe and a pressure of 35 Mpa to obtain a formed green body;

[0047] Step 5: Sinter the formed green body obtained in Step 4 at a temperature of 1200 °C for 6 h to obtain the final self-biased hexagonal ferrite gyromagnetic material.

[0048] Table 2 Performance table of Examples 1-16

[0049]

[0050] Table 5 Range analysis table of remanence ratio in Examples 1-16

[0051] Factor k1 k2 k3 k4 R CuO 0.81 0.81 0.56 0.53 0.28 <![CDATA[SiO2]]> 0.56 0.63 0.77 0.75 0.22 <![CDATA[Bi2O3]]> 0.81 0.82 0.66 0.42 0.39

[0052] Table 6 Range analysis table of magnetocrystalline anisotropy field in Examples 1-16

[0053] Factor k1 k2 k3 k4 R CuO 10680.95 10997.33 10742.63 10765.87 316.38 <![CDATA[SiO2]]> 10579.40 11037.40 10968.56 10601.42 458.00 <![CDATA[Bi2O3]]> 10667.19 10727.73 11128.72 10663.14 465.58

[0054] Example 17

[0055] The difference between this example and Example 1 is that:

[0056] Step 3: Perform range analysis on the remanence ratio results of Examples 1-16 to obtain the formula with the maximum remanence ratio, record it in Table 3, and add the Sr obtained in Step 2 0.8 La 0.2 Fe 11.8 Mn 0.2 O 19 Add CuO, SiO2, and Bi2O3 to the pre-sintered material according to the proportions in Table 3, perform secondary ball milling, and keep the ball-to-material ratio, time, and rotation speed the same as those in the primary ball milling. After filtering out the zirconia balls, a slurry is obtained.

[0057] Table 3 Injection amounts of additives in Example 17

[0058]

[0059]

[0060] Table 4 Performance table of Example 17

[0061]

[0062] The above examples merely illustrate the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above examples without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A self-biased hexagonal ferrite gyromagnetic material, characterized in that: It is a lanthanum and manganese doped uniaxial M-type hexagonal strontium ferrite material with a structural formula of Sr 0.8 La 0.2 Fe 11.8 Mn 0.2 O 19 The additive formula includes: CuO, SiO2, Bi2O3, calculated by weight percentage wt%, wherein the additive contains (0.1-0.7)% CuO, (0.1-0.8)% SiO2, and (0.1-0.6)% Bi2O3 of the ferrite material.

2. The self-biased hexagonal ferrite gyromagnetic material according to claim 1, characterized in that: The weight percentage of additives in ferrite materials is as follows: The weight percentage of additives in ferrite material (wt%) 。 3. The self-biased hexagonal ferrite gyromagnetic material according to claim 1, characterized in that: Calculated by weight percentage, the additives are 0.1% CuO, 0.6% SiO2, and 0.2% Bi2O3 in the ferrite material.

4. The self-biased hexagonal ferrite gyromagnetic material according to claim 1, characterized in that: The magnetocrystalline anisotropy field of the gyromagnetic material is 9987-11760 Oe, the remanence ratio is up to 87%, and the maximum density is 5.058 g / cm 3 .

5. The method for preparing the self-biased hexagonal ferrite gyromagnetic material according to any one of claims 1 to 4, characterized in that The following steps are involved: Step 1: According to the chemical formula Sr 0.8 La 0.2 Fe 11.8 Mn 0.2 O 19 Weigh the raw materials; according to the ratio of ball: material: water = 6:1:1, wherein the zirconia balls are configured according to the diameters of Ф12:Ф6:Ф3 = 1:2:3, the first ball milling time and the rotation speed are 720 min and 300 r / min respectively, to obtain a slurry; Step 2: drying the slurry obtained in step 1, sieving it, and pre-burning it at a temperature of 1225° C. for 6 hours to obtain a pre-burned material; Step 3: Sr obtained in step 2 0.8 La 0.2 Fe 11.8 Mn 0.2 O 19 Additives of CuO, SiO2 and Bi2O3 are added to the pre-sintered material, and the ball milling is performed for the second time. The ball milling ball-to-material ratio, time and speed are the same as those of the first ball milling. The zirconia balls are filtered out to obtain the slurry. Step 4: the water content of the slurry obtained in step 3 is controlled to be 30% to 35%, and wet magnetic field orientation molding is performed under an external magnetic field strength of 10KOe and a pressure of 35Mpa to obtain a molded green embryo; Step 5: The green body formed in step 4 is subjected to secondary sintering at a temperature of 1200° C. for 6 hours to obtain the final self-biased hexagonal ferrite gyromagnetic material.

6. The method for preparing the self-biased hexagonal ferrite gyromagnetic material according to claim 5, characterized in that: In step 3, the weight percentage of CuO, SiO2 and Bi2O3 added to the pre-sintered material is as follows: The weight percentage of additives in ferrite material (wt%) 。

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