Low-cost preparation method of high-frequency low-loss planar hexagonal ferrite material

Abstract

The invention discloses a low-cost preparation method of a high-frequency low-loss planar hexagonal ferrite material, and belongs to the technical field of ferrite material preparation. On the basis of a solid-phase reaction method, high-valence transition metal oxide additives such as Co2O3, MnO2, MoO2 and Nb2O5 are decomposed to release oxygen atoms during high-temperature sintering, and the vacancy concentration of planar hexagonal ferrite crystal lattices Fe < 2 + > and oxygen ions is reduced, so that the high-frequency magnetic conductivity of the material is effectively improved, and the high-frequency magnetic loss is reduced; the high-frequency low-loss planar hexagonal ferrite is sintered and prepared under the air condition. The method is mature in process, low in production cost and suitable for large-scale industrial production.

Description

Technical Field

[0001] The present invention belongs to the technical field of ferrite material preparation, and particularly relates to a low-cost preparation method for high-frequency and low-loss planar hexagonal ferrite materials. Background Art

[0002] With the rapid development of contemporary communication systems towards high frequency, miniaturization, and high efficiency, there is an urgent need for low-loss electromagnetic materials that can be applied at higher frequencies. Planar hexagonal ferrites, such as cobalt-titanium substituted M-type barium ferrite (Co-Ti BaM) and cobalt-doped Z-type ferrite (Co2Z), exhibit extremely broad application potential in fields such as high-frequency inductors and antenna substrates due to their high magnetic permeability, high dielectric constant, low electromagnetic loss, and high cut-off frequency. The high-frequency magnetic properties of planar hexagonal ferrites are closely related to the valence states of their cations and oxygen ion vacancies. The conduction mechanism of hexagonal ferrites mainly stems from the electron migration between divalent iron ions (Fe 2+ ) and trivalent iron ions (Fe 3+ ). A high concentration of Fe 2+ will significantly increase the magnetic loss of the material. Oxygen ion vacancies will disrupt the lattice electric field distribution and chemical bond bonding state of hexagonal ferrites, causing electrons to suffer additional scattering during migration, thereby significantly increasing the dielectric loss of the material. Oxygen ion vacancies will also weaken the super-exchange interaction between iron ions, reduce the orderliness of magnetic moment arrangement, and lead to a decrease in magnetic permeability. Therefore, suppressing the concentrations of divalent iron ions and oxygen ion vacancies in the material lattice is the key to preparing planar hexagonal ferrites with high magnetic permeability and low loss.

[0003] Sintering hexagonal ferrites in an oxygen-containing atmosphere is a commonly used method to suppress the concentrations of Fe 2+ and oxygen ion vacancies and reduce the high-frequency loss of the material. For example, Patent CN112661502A reduces the concentrations of Fe 2+ and oxygen ion vacancies by controlling the oxygen partial pressure during ferrite sintering, thereby reducing the high-frequency magnetic loss of the ferrite. In addition, annealing treatment can effectively repair lattice defects and reduce oxygen ion vacancies. For example, Patent CN113105227A uses a two-step annealing process to reduce the number of oxygen vacancies in Z-type ferrite, improving the magnetic permeability and saturation magnetization of the material; the University of Electronic Science and Technology of China (J. Chin Ceram Soc., 2006, 34(4): 398-402) significantly improves the densification of Co2Z hexagonal ferrite through high-temperature annealing, increasing the initial magnetic permeability to 33 and reducing the loss tangent. However, both oxygen sintering and annealing treatment increase the complexity of the material preparation process and equipment cost. Some chemical synthesis methods such as the sol-gel method can reduce oxygen ion defects caused by uneven composition. For example, Patent CN117228734A uses an alkaline co-precipitation system to sequentially precipitate Ba 2+ , Co2+ , Zn 2+ , Fe 3+ and Ti 4+ metal ions, 18H planar hexagonal ferrites with uniform phase composition were prepared, reducing lattice defects caused by non-uniform composition. However, the chemical synthesis method has many disadvantages such as a long process flow, high precursor cost, and unsuitability for large-scale industrial production. The valence state of iron ions and oxygen ion vacancies in hexagonal ferrites can also be regulated by metal ion doping. For example, Patent CN117285341A uses rare earth ion neodymium ions and transition metal ions (Zn 2+ , Co 2+ , Ni 2+ , Ti 4+ , Zr 4+ , etc.) to replace Ba 2+ and Fe 3+ in M-type barium ferrite respectively, promoting the transformation of Fe 3+ in the material lattice into Fe 2+ and introducing oxygen ion vacancies, thereby increasing the electromagnetic loss of the material for electromagnetic wave absorption; the University of Electronic Science and Technology of China (Physica B., 2013, 429, 85–89) replaced Fe 3+ in Co2Z hexagonal ferrite with Al 3+ , improving the material density and reducing the electron migration between Fe 2+ and Fe 3+ in the lattice, reducing the magnetic loss of the material.

[0004] Therefore, based on the traditional solid-phase reaction method for preparing hexagonal ferrites, preparing high-frequency low-loss planar hexagonal ferrites by sintering in air is of great significance for realizing the production of high-performance electromagnetic materials for high-frequency wireless communication devices at low cost and high efficiency. SUMMARY OF THE INVENTION

[0005] The purpose of the present invention is to propose a low-cost preparation method for high-frequency low-loss planar hexagonal ferrite materials in view of the problems such as strict sintering atmosphere, complex process flow, and high equipment cost in the preparation method of high-frequency low-loss planar hexagonal ferrite mentioned in the background technology.

[0006] Core idea of the present invention:

[0007] The present invention aims at Co2Z planar hexagonal ferrite (Ba3Co2Fe 24 O 41) The high-frequency loss caused by lattice defects and the valence change of iron ions in Co2Z planar hexagonal ferrites, as well as the mutual restriction relationship between high magnetic permeability and high cut-off frequency. Innovatively, high-valence transition metal oxide additives (such as Co2O3, MnO2, MoO2, Nb2O5, etc.) are used to simultaneously regulate the lattice oxygen vacancies, the valence state of iron ions, and the super-exchange interaction of magnetic ions, realizing triple optimization of the high-frequency magnetic properties of Co2Z planar hexagonal ferrites:

[0008] 1. Oxygen vacancies and Fe 2+ Inhibition: High-valence transition metal oxide additives release oxygen atoms during the sintering process. On the one hand, these oxygen atoms inhibit the generation of Fe in a non-oxygen-permeable atmosphere sintering, reducing the Fe 2+ concentration. On the other hand, they fill the lattice oxygen vacancies, reducing the oxygen vacancy concentration and effectively inhibiting the lattice relaxation loss. 2+

[0009] 2. Enhancement of the super-exchange interaction of magnetic ions: High-valence transition metal oxide additives decompose during the sintering process to produce low-valence magnetic ions (such as Co 2+ , Mn 2+ , Mo 2+ , etc.). These ions occupy the interstitial sites in the Co2Z planar hexagonal ferrite lattice and form super-exchange interactions with adjacent magnetic ions, enhancing the imbalance of the anti-parallel arranged magnetic moments and increasing the saturation magnetization intensity and the natural resonance frequency.

[0010] 3. Grain boundary barrier effect: The decomposition products of high-valence transition metal oxide additives (such as CoFe2O4, MnFe2O4) during the sintering process precipitate along the Co2Z grain boundaries in a nano-island structure (10 - 30 nm). These high-resistance phases form a potential barrier layer at the grain boundaries, increasing the grain boundary resistivity by several orders of magnitude and effectively inhibiting the high-frequency eddy current loss.

[0011] In particular, there is a unique synergistic effect between the Co2O3 additive and the Co2Z planar hexagonal ferrite. The Co generated by the decomposition of Co2O3 2+ can occupy the octahedral interstitial sites in the S block of the Co2Z planar hexagonal ferrite, reducing the covalency of the Fe-O bond through local electron cloud rearrangement and reducing the dielectric loss.

[0012] In summary, through the surface enrichment effect of sub-micron additives, the gradient regulation of the oxygen partial pressure can be realized under air sintering conditions, improving the initial magnetic permeability of Co2Z compared with the traditional process, while maintaining the cut-off frequency fr above 1.5 GHz. This directional regulation mechanism provides a new material solution for the application of planar hexagonal ferrites in high-frequency microwave devices.

[0013] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0014] A low-cost preparation method for a high-frequency and low-loss planar hexagonal ferrite material, comprising the following steps:

[0015] Step 1, ingredient preparation:

[0016] Weigh the raw material powders according to the chemical formula of the planar hexagonal ferrite, including BaCO3, Fe2O3, etc.;

[0017] Step 2, primary ball milling:

[0018] Mix the raw material powders obtained in Step 1 evenly in a ball mill, with a ball milling time of 2 to 4 hours, to obtain the primary ball milled material;

[0019] Step 3, pre-sintering:

[0020] Dry the primary ball milled material obtained in Step 2, and then pre-sinter it at 1160 - 1240 °C for 3 to 5 hours to generate the planar hexagonal ferrite pre-sintered material;

[0021] Step 4, doping:

[0022] Add high-valence transition metal oxide additives, including Co2O3, MnO2, MoO2, Nb2O5, etc., to the planar hexagonal ferrite pre-sintered material obtained in Step 3. The additives account for 0.1 - 1.5 wt% of the mass of the pre-sintered material, and the particle size of the additive powder is 0.4 - 0.8 μm;

[0023] Step 5, secondary ball milling:

[0024] Ball mill the mixed powder obtained in Step 4 in a ball mill for 6 to 12 hours;

[0025] Step 6, forming:

[0026] Dry the secondary ball milled material obtained in Step 5, add 7 wt% - 12 wt% of polyvinyl alcohol solution and mix evenly, and press it into a green body with a press. The forming pressure is 100 - 300 MPa, and the pressure holding time is 10 - 30 s;

[0027] Step 7, sintering:

[0028] Sinter the green body obtained in Step 6 in air at 1160 - 1240 °C for 3 to 5 hours to obtain the hexagonal ferrite sample.

[0029] Characterize the iron ion content, oxygen ion vacancy content, and complex permeability spectrum of the sample obtained in Step 7. The complex permeability spectrum of the sample is measured by a vector network analyzer and a coaxial air line fixture.

[0030] The present invention provides a high-frequency low-loss planar hexagonal ferrite material prepared by the above method. When the frequency f ≤ 300 MHz, the real part of the permeability μ' ≥ 10, the magnetic loss tangent tanδ ≤ 0.1, and the natural resonance frequency f0 ≥ 1 GHz.

[0031] The beneficial effects of the present invention are as follows:

[0032] The present invention provides a low-cost preparation method for a high-frequency low-loss planar hexagonal ferrite material. Based on the solid-phase reaction method, high-valence transition metal oxide additives are used to release oxygen atoms during high-temperature sintering, reducing the lattice Fe of the planar hexagonal ferrite 2+ and the oxygen ion vacancy concentration, thereby effectively improving the high-frequency permeability of the material, reducing the high-frequency magnetic loss, and realizing the sintering preparation of a high-frequency low-loss planar hexagonal ferrite under air conditions. This method has a mature process and low production cost, and is suitable for large-scale industrial production. Description of the Drawings

[0033] Figure 1 X-ray photoelectron spectrum of iron ions in Co2Z hexagonal ferrite in Example 1;

[0034] Figure 2 X-ray photoelectron spectrum of oxygen ions in Co2Z hexagonal ferrite in Example 1;

[0035] Figure 3 Complex permeability spectrum of Co2Z hexagonal ferrite in Example 1; where μ' is the real part of the permeability and μ" is the imaginary part of the permeability;

[0036] Figure 4 X-ray photoelectron spectrum of iron ions in Co2Z hexagonal ferrite in Comparative Example 1;

[0037] Figure 5 X-ray photoelectron spectrum of oxygen ions in Co2Z hexagonal ferrite in Comparative Example 1;

[0038] Figure 6 Complex permeability spectrum of Co2Z hexagonal ferrite in Comparative Example 1; where μ' is the real part of the permeability and μ" is the imaginary part of the permeability. Detailed Embodiments

[0039] The present invention provides a low-cost preparation method for a high-frequency low-loss planar hexagonal ferrite material. The following is a further technical description of the core idea and technical solution of the present invention through examples, but the present invention is not limited to these examples.

[0040] Example 1

[0041] Step 1, proportioning

[0042] According to the Co2Z hexagonal ferrite chemical formula Ba3Co2Fe 24 O 41 Calculate and weigh 22.07 mol% of BaCO3, 5.99 mol% of Co3O4, and 71.94 mol% of Fe2O3 raw material powders;

[0043] Step 2, primary ball milling

[0044] Ball mill the raw material powders obtained in Step 1 in a ball mill for 3 hours to mix them evenly, obtaining the primary ball milled material;

[0045] Step 3, pre-sintering

[0046] Dry the primary ball milled material obtained in Step 2, and then pre-sinter it at 1200 °C for 4 hours to obtain the Co2Z hexagonal ferrite pre-sintered material;

[0047] Step 4, doping

[0048] Add 0.5 wt% of MoO2 with a particle size of 0.5 μm to the hexagonal ferrite pre-sintered material obtained in Step 3;

[0049] Step 5, secondary ball milling

[0050] Ball mill the mixed powder obtained in Step 4 in a ball mill for 8 hours;

[0051] Step 6, forming

[0052] Dry the secondary ball milled material obtained in Step 5, add 10 wt% of polyvinyl alcohol solution and mix evenly, and press it into a green body with a forming pressure of 200 MPa and a holding pressure time of 20 s;

[0053] Step 7, sintering

[0054] Sinter the green body obtained in Step 6 in air at 1200 °C for 4 hours to obtain the hexagonal ferrite sample.

[0055] Example 2

[0056] Step 1, batching

[0057] According to the Co2Z hexagonal ferrite chemical formula Ba3Co2Fe 24 O 41 Calculate and weigh 22.07 mol% of BaCO3, 5.99 mol% of Co3O4, and 71.94 mol% of Fe2O3 raw material powders;

[0058] Step 2, primary ball milling

[0059] Ball mill the raw material powders obtained in Step 1 in a ball mill for 3 hours to mix them evenly, obtaining the primary ball milled material;

[0060] Step 3, Pre-sintering

[0061] Dry the primary milled material obtained in Step 2, and then pre-sinter at 1200 °C for 4 hours to obtain the Co2Z hexagonal ferrite pre-sintered material;

[0062] Step 4, Doping

[0063] Add 1 wt% of MoO2 with a particle size of 0.5 μm to the hexagonal ferrite pre-sintered material obtained in Step 3;

[0064] Step 5, Secondary Milling

[0065] Mill the mixed powder obtained in Step 4 in a ball mill for 8 hours;

[0066] Step 6, Forming

[0067] Dry the secondary milled material obtained in Step 5, add 10 wt% of polyvinyl alcohol solution and mix evenly, then press it into a green body with a forming pressure of 200 MPa and a pressure holding time of 20 s;

[0068] Step 7, Sintering

[0069] Sinter the green body obtained in Step 6 in air at 1200 °C for 4 hours to obtain the hexagonal ferrite sample.

[0070] Example 3

[0071] Step 1, Batching

[0072] According to the Co2Z hexagonal ferrite chemical formula Ba3Co2Fe 24 O 41 Calculate and weigh 22.07 mol% of BaCO3, 5.99 mol% of Co3O4 and 71.94 mol% of Fe2O3 raw material powders;

[0073] Step 2, Primary Milling

[0074] Mill the raw material powders obtained in Step 1 in a ball mill for 3 hours to mix evenly and obtain the primary milled material;

[0075] Step 3, Pre-sintering

[0076] Dry the primary milled material obtained in Step 2, and then pre-sinter at 1200 °C for 4 hours to obtain the Co2Z hexagonal ferrite pre-sintered material;

[0077] Step 4, Doping

[0078] Add 0.5 wt% of Co2O3 with a particle size of 0.5 μm to the hexagonal ferrite pre-sintered material obtained in Step 3;

[0079] Step 5: Secondary ball milling

[0080] Ball mill the mixed powder obtained in Step 4 in a ball mill for 8 hours;

[0081] Step 6: Forming

[0082] Dry the secondary ball milled material obtained in Step 5, add 10 wt% polyvinyl alcohol solution and mix evenly, then press it into a green compact with a forming pressure of 200 MPa and a pressure holding time of 20 s;

[0083] Step 7: Sintering

[0084] Sinter the green compact obtained in Step 6 in air at 1200 °C for 4 hours to obtain a hexagonal ferrite sample.

[0085] Example 4

[0086] Step 1: Batching

[0087] According to the chemical formula of Co2Z hexagonal ferrite Ba3Co2Fe 24 O 41 Calculate and weigh 22.07 mol% of BaCO3, 5.99 mol% of Co3O4 and 71.94 mol% of Fe2O3 raw material powders;

[0088] Step 2: Primary ball milling

[0089] Ball mill the raw material powders obtained in Step 1 in a ball mill for 3 hours to mix evenly and obtain a primary ball milled material;

[0090] Step 3: Pre-sintering

[0091] Dry the primary ball milled material obtained in Step 2, and then pre-sinter it at 1200 °C for 4 hours to obtain a Co2Z hexagonal ferrite pre-sintered material;

[0092] Step 4: Doping

[0093] Add 1 wt% of Co2O3 with a particle size of 0.5 μm to the hexagonal ferrite pre-sintered material obtained in Step 3;

[0094] Step 5: Secondary ball milling

[0095] Ball mill the mixed powder obtained in Step 4 in a ball mill for 8 hours;

[0096] Step 6: Forming

[0097] Dry the secondary ball milled material obtained in Step 5, add 10 wt% polyvinyl alcohol solution and mix evenly, then press it into a green compact with a forming pressure of 200 MPa and a pressure holding time of 20 s;

[0098] Step 7: Sintering

[0099] The green body obtained in step 6 was sintered in air at 1200° C. for 4 hours to obtain a hexagonal ferrite sample.

[0100] The comparative example is hexagonal ferrite prepared without adding high-valent transition metal oxide additive.

[0101] Comparative Example 1

[0102] Step 1: Ingredients

[0103] According to the chemical formula of Co2Z hexagonal ferrite Ba3Co2Fe 24 O 41 Calculate and weigh 22.07 mol% of BaCO3, 5.99 mol% of Co3O4, and 71.94 mol% of Fe2O3 raw material powders;

[0104] Step 2: First ball milling

[0105] The raw material powder obtained in step 1 is ball-milled in a ball mill for 3 hours to be mixed evenly to obtain a primary ball-milled material;

[0106] Step 3: Pre-burning

[0107] The primary ball-milled material obtained in step 2 is dried, and then pre-fired at 1200° C. for 4 hours to obtain a Co2Z hexagonal ferrite pre-fired material;

[0108] Step 4: Secondary ball milling

[0109] The hexagonal ferrite pre-sintered material obtained in step 3 was ball-milled in a ball mill for 8 hours;

[0110] Step 5: Molding

[0111] The secondary ball milled material obtained in step 4 is dried, 10 wt % polyvinyl alcohol solution is added and mixed evenly, and pressed into a green body by a press, the molding pressure is 200 MPa, and the holding time is 20 s;

[0112] Step 6: Sintering

[0113] The green body obtained in step 5 was sintered in air at 1200° C. for 4 hours to obtain a hexagonal ferrite sample.

[0114] Comparative Example 2

[0115] Step 1: Ingredients

[0116] According to the chemical formula of Co2Z hexagonal ferrite Ba3Co2Fe 24 O 41 Calculate and weigh 22.07 mol% of BaCO3, 5.99 mol% of Co3O4, and 71.94 mol% of Fe2O3 raw material powders;

[0117] Step 2: Primary ball milling

[0118] Ball mill the raw material powder obtained in Step 1 in a ball mill for 3 hours to mix evenly, obtaining primary ball milled material;

[0119] Step 3: Pre-sintering

[0120] Dry the primary ball milled material obtained in Step 2, and then pre-sinter at 1200 °C for 4 hours to obtain Co2Z hexagonal ferrite pre-sintered material;

[0121] Step 4: Secondary ball milling

[0122] Ball mill the hexagonal ferrite pre-sintered material obtained in Step 3 in a ball mill for 8 hours;

[0123] Step 5: Forming

[0124] Dry the secondary ball milled material obtained in Step 4, add 10 wt% polyvinyl alcohol solution and mix evenly, press into a green body with a press, the forming pressure is 200 MPa, and the pressure holding time is 20 s;

[0125] Step 6: Sintering

[0126] Sinter the green body obtained in Step 5 in oxygen at 1200 °C for 4 hours to obtain a hexagonal ferrite sample.

[0127] Experimental example

[0128] Samples: Examples 1-4 and Comparative Examples 1-2

[0129] Randomly sample the Co2Z hexagonal ferrite materials prepared in Examples 1-4 and Comparative Examples 1-2, and measure the iron ion content, oxygen ion vacancy content and complex permeability spectrum of the samples. Figure 1 X-ray photoelectron spectrum of iron ions in Co2Z hexagonal ferrite in Example 1; Figure 2 X-ray photoelectron spectrum of oxygen ions in Co2Z hexagonal ferrite in Example 1; Figure 3 Complex permeability spectrum of Co2Z hexagonal ferrite in Example 1; Figure 4 X-ray photoelectron spectrum of iron ions in Co2Z hexagonal ferrite in Comparative Example 1; Figure 5 X-ray photoelectron spectrum of oxygen ions in Co2Z hexagonal ferrite in Comparative Example 1; Figure 6 Complex permeability spectrum of Co2Z hexagonal ferrite in Comparative Example 1, where μ' is the real part of the permeability and μ" is the imaginary part of the permeability. The sample performance results are summarized in Table 1 below.

[0130] Table 1 Performance test results of different samples

[0131]

[0132] It can be seen from Table 1 that:

[0133] The Co2Z hexagonal ferrite material containing high-valent transition metal oxide additives prepared by Examples 1-4 has significantly better comprehensive performance than the comparative example after sintering under air conditions. Specifically, it is shown as follows:

[0134] 1. Compared with Comparative Example 1 (no additive, air sintering):

[0135] In the frequency band of 100-300MHz, the real part μ' of the magnetic permeability of Examples 1-4 is increased by about 15%-20% (e.g., 300MHz Example 1 μ'=11.0, Comparative Example 1 μ'=9.2), the magnetic loss tangent tanδ is reduced by 50%-60% (e.g., 300MHz Example 1 tanδ=0.08, Comparative Example 1 tanδ=0.19), and the natural resonance frequency f0 is increased to 1.6-2.0GHz, which is much higher than 1.3GHz of Comparative Example 1.

[0136] 2. Compared with Comparative Example 2 (no additive, oxygen sintering):

[0137] While maintaining similar real part of magnetic permeability μ' and magnetic loss tangent tanδ (e.g., 200MHz embodiment 2 μ'=12.0, comparative example 2 μ'=11.0; embodiment 2 tanδ=0.05, comparative example 2 tanδ=0.06) in embodiments 1-4, the natural resonance frequency f0 is increased to 1.6-2.0 GHz, which is better than 1.5 GHz of comparative example 2.

[0138] The above results show that the invention effectively inhibits the generation of Fe2+ ions and oxygen vacancies by introducing high-valent transition metal oxide additives, thereby achieving a breakthrough in material performance under air sintering conditions. Its performance not only greatly exceeds the traditional air sintering process, but also reaches or even exceeds similar materials that require complex oxygen sintering processes.

[0139] The present invention provides an innovative solution for the industrial production of high-frequency and low-loss planar hexagonal ferrite by simplifying the sintering environment and reducing process costs, and has significant technical and economic value.

[0140] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A low-cost preparation method for high-frequency low-loss planar hexagonal ferrite material, characterized in that: The following steps are involved: Step 1. Ingredients: Calculate and weigh the raw material powder according to the chemical formula of planar hexagonal ferrite; Step 2: First ball milling: The raw material powder obtained in step 1 is ball-milled and mixed uniformly to obtain a primary ball-milled material; Step 3: Pre-burning: The primary ball milled material obtained in step 2 is dried, and then pre-fired at 1160-1240° C. for 3-5 hours to form a planar hexagonal ferrite pre-fired material; Step 4: Doping: Adding a high-valent transition metal oxide additive to the planar hexagonal ferrite pre-sintered material obtained in step 3, wherein the additive accounts for 0.1 to 1.5 wt% of the mass of the pre-sintered material; Step 5: Secondary ball milling: The mixed powder obtained in step 4 is subjected to secondary ball milling; Step 6: Molding: Drying the secondary ball milled material obtained in step 5 and pressing it into a green compact; Step 7: Sintering: The green body obtained in step 6 is sintered in air at 1160-1240° C. for 3-5 hours to obtain a hexagonal ferrite sample.

2. The low-cost preparation method of high-frequency low-loss planar hexagonal ferrite material according to claim 1, characterized in that: The planar hexagonal ferrite in step 1 is Co2Z hexagonal ferrite.

3. The low-cost preparation method of high-frequency low-loss planar hexagonal ferrite material according to claim 1, characterized in that: In step 2, the ball milling time is 2 to 4 hours.

4. The low-cost preparation method of high-frequency low-loss planar hexagonal ferrite material according to claim 1, characterized in that: In step 4, the high-valent transition metal oxide additive is Co2O3, MnO2, MoO2 or Nb2O5, and the particle size of the additive powder is 0.4 to 0.8 μm.

5. The low-cost preparation method of high-frequency low-loss planar hexagonal ferrite material according to claim 1, characterized in that: In step 5, the time of the secondary ball milling is 6 to 12 hours.

6. The low-cost preparation method of high-frequency low-loss planar hexagonal ferrite material according to claim 1, characterized in that: In step 6, the pressure of the pressing molding is 100-300 MPa, and the holding time is 10-30 s.

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