Manganese-zinc ferrite wave-absorbing material and preparation method thereof

Abstract

The application belongs to the technical field of magnetic materials, and provides a manganese-zinc ferrite wave-absorbing material and a preparation method thereof.The method comprises the following steps: mixing ferroferric oxide, trimanganese tetroxide and zinc oxide to pre-sinter, to obtain pre-sintered material; mixing the pre-sintered material with a polyvinyl alcohol solution, and shaping, to obtain a green body; sintering the green body under a mixed atmosphere of nitrogen and oxygen, to obtain the manganese-zinc ferrite wave-absorbing material.The application has the advantages of simple preparation process, controllable cost, suitability for large-scale production, and the like, and the obtained manganese-zinc ferrite wave-absorbing material has good wave-absorbing performance in a low-frequency P wave band of microwaves, and the lowest reflection loss can reach-28 dB at a thickness of 5.00 mm, basically covering the entire wave band.The manganese-zinc ferrite wave-absorbing material prepared by the application has a wide application prospect in the civil field as a single type of absorber.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of magnetic materials, and particularly relates to a manganese-zinc ferrite wave-absorbing material and a preparation method thereof. BACKGROUND

[0002] With the continuous development of modern science and technology, electronic communication and communication equipment greatly improve people's daily life, but the electromagnetic radiation and electromagnetic interference generated by electronic products during work will cause certain harm to people's body and production and life. The wave-absorbing material can effectively eliminate the pollution of electromagnetic radiation and is widely used in national defense, military, civil, medical and other fields.

[0003] The manganese-zinc ferrite with a spinel structure has dielectric properties and magnetic properties, is a double-composite loss material, and has high magnetic permeability at low frequencies, so it has considerable wave-absorbing performance below GHz frequency. According to the Federal Communications Commission of the United States and the European Union standard, the lower limit of the test frequency of electromagnetic compatibility (EMC) experiment is 30MHz, so the low-frequency wave-absorbing performance of the wave-absorbing material has attracted much attention. At the same time, the current wave-absorbing material is developing in the direction of "thin, light, strong and wide", that is, thinner, lighter, stronger and wider absorption frequency band. However, for the manganese-zinc ferrite material, in the low-frequency range of the microwave band, due to the low frequency and long wavelength, according to the 1 / 4 wavelength theory, as a wave-absorbing material, there is a problem of too large thickness in actual use, which has brought great challenges to industrial production and application. At the same time, the impedance matching problem of adjusting its dielectric constant and magnetic permeability is also a difficulty. According to the existing technical reports, CN114591075A discloses a manganese-zinc ferrite soft magnetic alloy wave-absorbing material and a preparation process, which solves the problems of narrow absorption frequency band and poor wave-absorbing performance of the existing manganese-zinc ferrite wave-absorbing material above GHz band, adopts a casting machine to obtain a casting film, and finally sintering to obtain a sample to be tested. Specifically, at a thickness of only 2.5mm, the effective bandwidth is 1GHz (15-16GHz), and the minimum absorption value is-12.76dB (15.6GHz). When the thickness is 4.5mm, the effective bandwidth is 1.9GHz (7.1-9GHz), and the minimum absorption value is-11.5dB. This patent relates to a wave-absorbing material above 1GHz. CN111138184A discloses a carbon-composite cerium-doped manganese-zinc ferrite wave-absorbing material and a preparation method thereof. The manganese-zinc ferrite wave-absorbing material prepared by a hydrothermal method has an absorption bandwidth of less than-10dB of 10GHz at a simulated thickness of 2.5mm, and has good wave-absorbing performance and effective absorption bandwidth in the range of 2-18GHz. This patent also relates to a wave-absorbing material above 1GHz.

[0004] Based on the above analysis, the existing research on the manganese-zinc ferrite wave-absorbing material mostly focuses on the wave band above GHz, and the wave-absorbing performance in the MHz range is rarely concerned, and the wave-absorbing performance in the MHz range is not good enough to meet the needs of the service environment. Therefore, it is of practical production significance to design and prepare the manganese-zinc ferrite material with good wave-absorbing performance in the low-frequency P wave band. SUMMARY

[0005] The purpose of the present application is to overcome the problems existing in the prior art, and to provide a manganese-zinc ferrite wave-absorbing material and a preparation method thereof.

[0006] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical solutions:

[0007] The present application provides a preparation method of a manganese-zinc ferrite wave-absorbing material, comprising the following steps:

[0008] (1) mixing ferric oxide, trimanganese tetroxide and zinc oxide for pre-sintering to obtain pre-sintered material;

[0009] (2) mixing the pre-sintered material with a polyvinyl alcohol solution and forming to obtain a green body;

[0010] (3) sintering the green body in a mixed atmosphere of nitrogen and oxygen to obtain the manganese-zinc ferrite wave-absorbing material.

[0011] Preferably, the mass ratio of the ferric oxide, trimanganese tetroxide and zinc oxide in step (1) is 64-70:14-20:13-16.

[0012] Preferably, the raw materials mixed in step (1) further comprise an ion substitution reagent.

[0013] The ion substitution reagent comprises one or more of cobalt tetroxide, copper oxide and magnesium oxide.

[0014] The mass ratio of the ferric oxide, trimanganese tetroxide, zinc oxide and ion substitution reagent is 64-70:14-20:13-16:0-5, and the mass of the ion substitution reagent is not 0.

[0015] Preferably, the pre-sintering temperature in step (1) is 800-1000℃, and the time is 2.0-3.5h.

[0016] Preferably, the mass fraction of the polyvinyl alcohol solution in step (2) is 2-10%;

[0017] The mass ratio of the ferric oxide, trimanganese tetroxide and zinc oxide in step (1) to the mass of the polyvinyl alcohol solution in step (2) is 100:8-12.

[0018] When an ion substitution agent is included, the mass ratio of the ferric oxide, manganese manganese oxide, zinc oxide and the ion substitution agent to the polyvinyl alcohol solution in step (2) is 100:8-12.

[0019] Preferably, the molding pressure in step (2) is 500-800 kg / cm 2 , the holding time is 1.5 to 2.5 minutes.

[0020] Preferably, the heating rate of the sintering in step (3) is 3 to 8°C / min, the target temperature of the sintering is 1300 to 1350°C, and the holding time after reaching the target temperature is 3 to 5 hours;

[0021] The volume fraction of oxygen in the mixed atmosphere is 2 to 25%.

[0022] The present invention also provides a manganese-zinc ferrite wave absorbing material obtained by the preparation method.

[0023] The beneficial effects of the present invention are:

[0024] The present invention provides a method for preparing a manganese-zinc ferrite absorbing material, comprising the following steps: pre-sintering a mixture of ferric oxide, manganese tetraoxide, and zinc oxide to obtain a pre-sintered material; mixing the pre-sintered material with a polyvinyl alcohol solution and forming the mixture to obtain a green body; and sintering the green body in a mixed atmosphere of nitrogen and oxygen to obtain the manganese-zinc ferrite absorbing material. The preparation process of the present invention is simple, cost-controlled, and suitable for large-scale production. The prepared manganese-zinc ferrite absorbing material has excellent absorbing performance in the microwave low-frequency P band. At a thickness of 5.00 mm, its reflection loss can be as low as -28 dB, essentially covering the entire band. As a single-type absorber, the manganese-zinc ferrite absorbing material prepared by the present invention has broad application prospects, particularly in the civilian field. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The XRD characterization diagram of the manganese zinc ferrite absorbing material obtained in Examples 1 to 4, wherein 2θ (degree) is 2θ (°), and Intensity (au) is intensity (au);

[0026] Figure 2 The SEM characterization of the manganese zinc ferrite absorbing material obtained in Examples 1 to 4 ( Figure 2 In the figure, Figure (1) is a SEM characterization diagram of the manganese-zinc ferrite absorbing material obtained in Example 1, Figure (2) is a SEM characterization diagram of the manganese-zinc ferrite absorbing material obtained in Example 2, Figure (3) is a SEM characterization diagram of the manganese-zinc ferrite absorbing material obtained in Example 3, and Figure (4) is a SEM characterization diagram of the manganese-zinc ferrite absorbing material obtained in Example 4);

[0027] Figure 3 Fig. 1 is a B-H loop diagram of the manganese-zinc ferrite wave-absorbing material obtained in Example 1, Fig. 2 is a B-H loop diagram of the manganese-zinc ferrite wave-absorbing material obtained in Example 2, Fig. 3 is a B-H loop diagram of the manganese-zinc ferrite wave-absorbing material obtained in Example 3, and Fig. 4 is a B-H loop diagram of the manganese-zinc ferrite wave-absorbing material obtained in Example 4, wherein H (A / m) is magnetic field intensity (A / m) and B (T) is magnetic induction intensity (T) ; Figure 3

[0028] Figure 4 Fig. 5 is a complex permeability spectrum diagram of the manganese-zinc ferrite wave-absorbing material obtained in Example 1-4, wherein Frequency (HZ) is frequency (HZ) and Complex permeability is complex permeability;

[0029] Figure 5 Fig. 6 is a complex permittivity spectrum diagram of the manganese-zinc ferrite wave-absorbing material obtained in Example 1-4, wherein Frequency (HZ) is frequency (HZ) and Complex permittivity is complex permittivity;

[0030] Figure 6 Fig. 7 is a reflection loss spectrum diagram of the manganese-zinc ferrite wave-absorbing material obtained in Example 1-4, wherein Frequency (MHZ) is frequency (MHZ) and RL (dB) is reflection loss (dB) ;

[0031] Figure 7 Fig. 8 is a reflection loss spectrum diagram of the manganese-zinc ferrite wave-absorbing material obtained in Example 2 and Comparative Example 1, wherein Frequency (MHZ) is frequency (MHZ) and RL (dB) is reflection loss (dB). DETAILED DESCRIPTION

[0032] The present application provides a preparation method of a manganese-zinc ferrite wave-absorbing material, comprising the following steps:

[0033] (1) mixing ferric oxide, trimanganese tetroxide and zinc oxide to pre-sinter, to obtain pre-sintered material;

[0034] (2) mixing the pre-sintered material with polyvinyl alcohol solution, and molding, to obtain green body;

[0035] (3) sintering the green body under a mixed atmosphere of nitrogen and oxygen, to obtain the manganese-zinc ferrite wave-absorbing material.

[0036] ​In the present application, the mass ratio of the ferric oxide, trimanganese tetraoxide and zinc oxide in step (1) is preferably 64-70:14-20:13-16, further preferably 65-69:15-19:13.5-15.5, and more preferably 66-67:16-18:14-15.

[0037] In the present application, the ion substitution reagent is preferably one or more of cobalt tetraoxide, copper oxide and magnesium oxide.

[0038] In the present application, the mass ratio of the ferric oxide, trimanganese tetraoxide, zinc oxide and ion substitution reagent is preferably 64-70:14-20:13-16:0-5, and the mass of the ion substitution reagent is not 0, further preferably 65-69:15-19:13.5-15.5:1-4, and more preferably 66-67:16-18:14-15:2-3.

[0039] In the present application, after mixing in step (1), the obtained mixture is mixed with water, ball-milled, dried, and then pressed into a cake, and then pre-fired.

[0040] In the present application, the mass ratio of the mixture to water is preferably 1:1-2, further preferably 1:1.2-1.8, and more preferably 1:1.5-1.6; the rotation speed of the ball-milling is preferably 80-120 r / min, further preferably 90-110 r / min, and more preferably 100-105 r / min; the ball-milling time is preferably 3-5 h, further preferably 3.5-4.5 h, and more preferably 3.7-4 h; the drying temperature is preferably 60-120℃, further preferably 70-110℃, and more preferably 90-100℃; and the drying time is preferably 8-12 h, further preferably 9-11 h, and more preferably 10-10.5 h.

[0041] In the present application, the pre-firing temperature in step (1) is preferably 800-1000℃, further preferably 850-950℃, and more preferably 900-920℃; and the time is preferably 2.0-3.5 h, further preferably 2.5-3.0 h, and more preferably 2.7-2.8 h.

[0042] In the present application, after the pre-firing in step (1) is completed, the obtained sample is coarsely broken to obtain a broken powder, and then water is added for ball-milling, and after the ball-milling is completed, drying is performed, and then step (2) is performed.

[0043] In the present application, the mass ratio of the broken powder to water is preferably 1:1-2, further preferably 1:1.2-1.8, and more preferably 1:1.5-1.6; the rotation speed of the ball mill is preferably 130-170 r / min, further preferably 140-160 r / min, and more preferably 150-155 r / min; the time of the ball mill is preferably 5-7 h, further preferably 5.5-6.5 h, and more preferably 5.7-6 h; the temperature of the drying is preferably 60-120°C, further preferably 70-110°C, and more preferably 90-100°C; and the time of the drying is preferably 8-12 h, further preferably 9-11 h, and more preferably 10-10.5 h.

[0044] In the present application, the mass fraction of the polyvinyl alcohol solution in step (2) is preferably 2-10%, further preferably 3-8%, and more preferably 5-6%.

[0045] In the present application, the mass ratio of the ferric oxide, trimanganese tetroxide and zinc oxide in step (1) to the polyvinyl alcohol solution in step (2) is preferably 100:8-12, further preferably 100:9-11, and more preferably 100:10-10.5.

[0046] In the present application, when the ion substitution reagent is contained, the mass ratio of the ferric oxide, trimanganese tetroxide, zinc oxide and ion substitution reagent to the polyvinyl alcohol solution in step (2) is preferably 100:8-12, further preferably 100:9-11, and more preferably 100:10-10.5.

[0047] In the present application, the pre-sintered material is mixed with the polyvinyl alcohol solution, granulated, and then formed.

[0048] In the present application, the granulation is completed by conventional technical means in the art.

[0049] In the present application, the pressure for the forming in step (2) is preferably 500-800 kg / cm 2 , further preferably 600-700 kg / cm 2 , and more preferably 630-650 kg / cm 2 ; and the pressure holding time is preferably 1.5-2.5 min, further preferably 1.7-2.3 min, and more preferably 2-2.2 min.

[0050] In the present application, the heating rate of the sintering in step (3) is preferably 3-8℃ / min, further preferably 4-7℃ / min, and more preferably 5-6℃ / min; the target temperature of the sintering is preferably 1300-1350℃, further preferably 1310-1340℃, and more preferably 1320-1330℃; and the holding time after reaching the target temperature is preferably 3-5h, further preferably 3.5-4.5h, and more preferably 3.7-4h.

[0051] In the present application, the oxygen content is controlled by adjusting the volume ratio of nitrogen and oxygen in the mixed atmosphere during the heating and sintering process, and specifically, the volume fraction of oxygen in the mixed atmosphere is preferably 2-25%, further preferably 5-20%, and more preferably 10-15%; under such atmosphere, the sintering can obtain a higher performance of the manganese-zinc ferrite wave-absorbing material compared to air sintering.

[0052] In the present application, after the sintering is completed, cooling is performed to obtain the manganese-zinc ferrite wave-absorbing material.

[0053] In the present application, the cooling comprises the following steps: after the sintering is completed, stopping the input of nitrogen and oxygen, allowing the system to cool to a first temperature, then cooling to a second temperature by vacuumizing, and then inputting nitrogen and cooling to a target temperature in a nitrogen atmosphere; the present application controls the oxygen content by using the way of hierarchical cooling and vacuumizing; in addition, the way of vacuumizing can ensure that the sample will not crack due to too fast cooling rate, and the internal stress is small.

[0054] In the present application, the first temperature is preferably 1180-1220℃, further preferably 1190-1210℃, and more preferably 1200-1205℃; the second temperature is preferably 680-720℃, further preferably 690-710℃, and more preferably 700-705℃; and the target temperature is preferably 20-30℃, further preferably 22-28℃, and more preferably 25-26℃.

[0055] In the present application, the control of the oxygen content in the sintering stage and the cooling stage is a key step to ensure that the manganese-zinc ferrite material has good wave-absorbing performance; in the sintering stage, the present application inputs a mixed atmosphere of N2 and O2, and controls the oxygen content by setting a certain content of O2; in the cooling stage, the input of nitrogen and oxygen is stopped first, the system is cooled to a first temperature, then vacuum cooling is used, and finally the oxygen content in the cooling stage is controlled by inputting nitrogen, so that the sample is cooled in a balanced atmosphere, thereby having good magnetic properties and wave-absorbing performance, and being able to realize the maximum absorption of P-band electromagnetic waves.

[0056] The present application also provides the manganese-zinc ferrite wave-absorbing material obtained by the preparation method.

[0057] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0058] Example 1

[0059] The ferric oxide, manganese tetraoxide and zinc oxide (the total weight of the ferric oxide, manganese tetraoxide and zinc oxide is 150g, and the mass ratio of the ferric oxide, manganese tetraoxide and zinc oxide is 65.59:18.64:15.77) is mixed to obtain a mixture, and then the mixture is mixed with water (the mass ratio of the mixture to water is 1:1.5), ball milled at a speed of 100r / min for 4h, and then dried at 100℃ for 10h. After drying, it is pressed into a cake blank, pre-calcined at 900℃, and the holding time is set to 3h. The obtained sample is coarsely crushed to obtain a crushed powder, and then water is added (the mass ratio of the crushed powder to water is 1:1.5), ball milled at a speed of 150r / min for 6h, dried at 100℃ for 10h after the ball milling, and then 15g of a 6% polyvinyl alcohol solution is added to granulate, and then 2 The green body with an outer diameter of 7 mm and an inner diameter of 3 mm was obtained by molding under a pressure of , setting the holding time to 2 min;

[0060] In a mixed atmosphere of nitrogen and oxygen, the green body was heated to 1320°C at a heating rate of 5°C / min for sintering (the volume fraction of oxygen in the mixed atmosphere was 20% during the heating and sintering process), and the holding time was set to 3h. After the sintering was completed, the nitrogen and oxygen were stopped, and the system was cooled to 1200°C, and then cooled to 700°C by vacuuming, and then nitrogen was introduced. It was cooled to 25°C in the furnace under a nitrogen atmosphere to obtain a manganese-zinc ferrite absorbing material.

[0061] Example 2

[0062] While keeping other conditions in Example 1 unchanged, copper oxide was added to the pre-fired mixture. The total weight of ferric oxide, manganese manganese tetroxide, zinc oxide, and copper oxide was set to 150 g. The mass ratio of ferric oxide, manganese manganese tetroxide, zinc oxide, and copper oxide was 67:16.42:14.34:2.24 to obtain a manganese-zinc ferrite absorbing material.

[0063] Example 3

[0064] While keeping other conditions in Example 1 unchanged, cobalt oxide was added to the pre-fired mixture, and the total weight of ferric oxide, manganese oxide, zinc oxide, and cobalt oxide was set to 150 g. The mass ratio of ferric oxide, manganese oxide, zinc oxide, and cobalt oxide was 66.08:19.42:13.82:0.68 to obtain a manganese-zinc ferrite absorbing material.

[0065] Example 4

[0066] While keeping other conditions in Example 1 unchanged, a mixture of magnesium oxide and copper oxide was added to the pre-fired mixture. The total weight of ferric oxide, manganese manganese tetroxide, zinc oxide, magnesium oxide, and copper oxide was set to 150 g. The mass ratio of ferric oxide, manganese manganese tetroxide, zinc oxide, magnesium oxide, and copper oxide was 65.92:14.85:15.85:1.02:2.36 to obtain a manganese-zinc ferrite absorbing material.

[0067] Comparative Example 1

[0068] The other conditions in Example 2 were controlled to remain unchanged, and after the sintering was completed, the oxygen flow was stopped during the process of cooling the system to 1200° C., while the nitrogen flow was continued.

[0069] The samples obtained in Examples 1 to 4 were subjected to XRD and SEM microstructure characterization analysis to obtain XRD characterization patterns of the manganese zinc ferrite absorbing materials obtained in Examples 1 to 4, as shown in FIG. Figure 1 As shown; SEM characterization of the manganese zinc ferrite absorbing material obtained in Examples 1 to 4, as shown Figure 2 As shown ( Figure 2 In the figure, Figure (1) is the SEM characterization picture of the manganese-zinc ferrite absorbing material obtained in Example 1, Figure (2) is the SEM characterization picture of the manganese-zinc ferrite absorbing material obtained in Example 2, Figure (3) is the SEM characterization picture of the manganese-zinc ferrite absorbing material obtained in Example 3, and Figure (4) is the SEM characterization picture of the manganese-zinc ferrite absorbing material obtained in Example 4). Figure 1 It can be seen from the above that Examples 1 to 4 all generate pure spinel ferrite phase without any impurity phase. Figure 2 It can be seen from the figure that the particles of Examples 1 to 4 have uniform size and good density.

[0070] The samples obtained in Examples 1 to 4 were subjected to magnetic parameter tests under static DC conditions to obtain the BH loop diagrams of the manganese-zinc ferrite absorbing materials obtained in Examples 1 to 4, as shown in FIG. Figure 3 As shown ( Figure 3 In the figure, Figure (1) is the BH loop diagram of the manganese zinc ferrite absorbing material obtained in Example 1, Figure (2) is the BH loop diagram of the manganese zinc ferrite absorbing material obtained in Example 2, Figure (3) is the BH loop diagram of the manganese zinc ferrite absorbing material obtained in Example 3, and Figure (4) is the BH loop diagram of the manganese zinc ferrite absorbing material obtained in Example 4); the electromagnetic parameters of the samples obtained in Examples 1 to 4 were measured using a vector network analyzer, and the obtained Figure 4 and Figure 5 , Figure 4 The magnetic permeability spectra of the manganese-zinc ferrite absorbing materials obtained in Examples 1 to 4 are shown;

[0071] Figure 5The dielectric constant spectra of the manganese zinc ferrite absorbing materials obtained in Examples 1 to 4 are shown in FIG. Figure 4 and Figure 5 The complex permeability, complex dielectric constant and sample thickness obtained in the above are substituted into the transmission line theory calculation formula to calculate the reflection loss value, and the reflection loss spectrum of the manganese zinc ferrite absorbing material obtained in Examples 1 to 4 is obtained, as shown in FIG. Figure 6 As shown. Figure 3 The saturation magnetic induction intensity and coercive force of the sample can be seen from Figure 4 It can be seen from the figure that the relationship between the complex permeability and the frequency shows a dispersion distribution. As the frequency increases, the complex permeability decreases. Figure 5 It can be seen that within this frequency range, the complex dielectric constant of the sample hardly changes with frequency.

[0072] In addition, Figure 6 The specific results are recorded in Table 1, and the absorbing performance results of the manganese-zinc ferrite absorbing materials obtained in Examples 1 to 4 are obtained, as shown in Table 1. Under a certain material thickness, the reflection loss (RL) is generally used to evaluate the absorbing performance of the material. When RL is less than -10dB, the material will absorb 90% of the incident electromagnetic wave energy; when RL is less than -20dB, the material will absorb 99% of the incident electromagnetic wave energy.

[0073] Table 1 Wave absorbing performance results of the manganese zinc ferrite wave absorbing materials obtained in Examples 1 to 4

[0074]

[0075]

[0076] As can be seen from Table 1, Examples 1 to 4 prepared manganese zinc ferrite materials covering the entire P band and having good wave absorbing performance.

[0077] The reflection loss spectra of the manganese zinc ferrite absorbing materials obtained in Example 2 and Comparative Example 1 were obtained using the same testing method. Figure 7 shown; from Figure 7 It can be seen that at the same thickness, with different oxygen control methods, the minimum reflection loss value of Comparative Example 1 is -5dB less than that of Example 2.

[0078] As demonstrated in the above examples, the present invention features a simple preparation process, manageable costs, and suitability for large-scale production. The resulting manganese-zinc ferrite absorbing material exhibits excellent microwave absorption performance in the low-frequency P-band. At a thickness of 5.00 mm, its reflection loss can reach a minimum of -28 dB, essentially covering the entire microwave band. As a single-type absorber, the manganese-zinc ferrite absorbing material prepared by the present invention has broad application prospects, particularly in civilian applications.

[0079] The above merely describes the preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the protection scope of the present application.

Claims

1. A method for preparing a manganese zinc ferrite absorbing material, characterized in that: It includes the following steps: (1) mixing ferric oxide, manganese manganese tetroxide and zinc oxide and pre-calcining to obtain a pre-calcined material; (2) mixing the pre-sintered material with the polyvinyl alcohol solution and forming the pre-sintered material to obtain a green body; (3) sintering the green compact in a mixed atmosphere of nitrogen and oxygen to obtain the manganese-zinc ferrite absorbing material; The mass ratio of ferric oxide, manganese tetraoxide and zinc oxide in step (1) is 64-70:16-20:13-16; The molding pressure in step (2) is 500-800 kg / cm 2 , the holding time is 1.5 to 2.5 minutes; The heating rate of the sintering in step (3) is 3 to 8°C / min, the target temperature of the sintering is 1300 to 1350°C, and the holding time after reaching the target temperature is 3 to 5 hours; The volume fraction of oxygen in the mixed atmosphere is 5 to 25%; After the sintering is completed in step (3), the temperature is lowered, and the cooling comprises the following steps: after the sintering is completed, the introduction of nitrogen and oxygen is stopped, the system is cooled to a first temperature, and then the system is cooled to a second temperature by vacuuming, and then nitrogen is introduced again, and the system is cooled to a target temperature in a nitrogen atmosphere; the first temperature is 1180-1220°C; the second temperature is 680-720°C; and the target temperature is 20-30°C.

2. The preparation method according to claim 1, wherein The raw materials mixed in step (1) further include an ion substitution agent; The ion replacement reagent comprises one or more of cobalt trioxide, copper oxide and magnesium oxide; The mass ratio of the ferric oxide, manganese manganese tetroxide, zinc oxide and ion replacement agent is 64-70:16-20:13-16:0-5, and the mass of the ion replacement agent is not 0.

3. The preparation method according to claim 2, wherein The pre-firing temperature in step (1) is 800-1000° C. and the pre-firing time is 2.0-3.5 hours.

4. The preparation method according to claim 3, wherein The mass fraction of the polyvinyl alcohol solution in step (2) is 2 to 10%; The mass ratio of the sum of the ferric oxide, manganese tetraoxide and zinc oxide in step (1) to the polyvinyl alcohol solution in step (2) is 100:8-12; When an ion substitution agent is included, the mass ratio of the ferric oxide, manganese manganese oxide, zinc oxide and the ion substitution agent to the polyvinyl alcohol solution in step (2) is 100:8-12.

5. The manganese zinc ferrite absorbing material obtained by the preparation method according to any one of claims 1 to 4.

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