Preparation method of heterogenous ion double-position modified barium ferrite wave-absorbing powder and wave-absorbing coating and corresponding products

Abstract

The invention relates to the technical field of wave-absorbing materials, and provides a preparation method of different-quantity ion double-position modified barium ferrite wave-absorbing powder and a wave-absorbing coating and a corresponding product of the different-quantity ion double-position modified barium ferrite wave-absorbing powder and the wave-absorbing coating. Comprising the following steps: preparing a modified barium ferrite wave-absorbing powder precursor solution from an acetate composition, a nitrate composition, citrate, deionized water and an ammonium hydroxide solution; carrying out gelling treatment on the modified barium ferrite wave-absorbing powder precursor solution; carrying out drying treatment on a gelling product; carrying out combustion treatment on the prepared modified barium ferrite wave-absorbing powder precursor; carrying out first grinding treatment on a combustion product; and preparing the hetero-ion double-position modified barium ferrite wave-absorbing powder. The microstructure and the internal structure of the barium ferrite can be changed, the natural formant is adjustable, the excellent wave-absorbing efficiency is obtained, and the Curie temperature and the high-temperature stability are improved.

Description

Technical Field

[0001] The present application relates to the technical field of absorbing materials, and in particular to a preparation method of heteroion double-site modified barium ferrite absorbing powder and absorbing coating and corresponding products. Background Art

[0002] With the continuous development of electromagnetic wave technology, it is increasingly widely used in many fields such as aviation measurement and control, communication, radar, medical electronics, remote sensing, etc. It has brought great convenience to people's daily life, but it also has some negative effects that endanger human health. At the same time, military radar technology and millimeter wave communication have put forward higher technical requirements for high-frequency absorbing materials. In addition to considering the basic absorbing requirements: thin thickness, light weight, wide absorption frequency band, and strong absorbing efficiency, the electromagnetic wave application conditions must also be considered, and the surrounding environment must have a good high temperature resistance and be able to maintain stable performance in high temperature environments.

[0003] M-type barium ferrite has high magnetic permeability, high resistivity, and good impedance matching performance. It mainly loses electromagnetic waves through self-polarization, hysteresis resonance, domain wall resonance, and natural resonance. Its strong c-axis anisotropy leads to a higher resonance frequency, which is about 42.5GHz, close to the atmospheric window frequency of 35GHz. It is very likely to become an excellent absorbing material near this window. However, it has the disadvantages of narrow absorption band, high density, and poor thermal stability, which cannot meet the application requirements of high-frequency absorbing materials. Studies have found that by changing the preparation process of barium ferrite, its various properties can be improved to a certain extent.

[0004] Ion doping modification is the most effective, fastest and simplest method to improve the properties of barium ferrite. It usually replaces the Fe at the b position of M-type barium ferrite. 3+ Improve the microwave absorption performance, study the crystal structure of M-type barium ferrite, and find that in barium ferrite, in addition to the Fe at the b position 3+ , replace Ba in position a 2+ It can also regulate its natural resonance peak and its performance. However, there are few reports on the performance of barium ferrite modified by heteroatom ions at high frequency windows. The Chinese patent with publication number CN114956192A discloses a method for preparing di-substituted barium ferrite, but the scheme cannot control the substitution amount. When only the material prepared by the same amount of substitution is used, the absorption strength near the window is insufficient and cannot meet practical applications.

[0005] Therefore, how to design a barium ferrite absorbing material with dual-site doping of heterogeneous ions, high absorption intensity at the window, meeting the coating technology requirements and maintaining stable performance at high temperatures has become an urgent problem to be solved. Summary of the invention

[0006] In view of this, in order to overcome the deficiencies of the prior art, the present application aims to provide a method for preparing anisotropic ion-modified barium ferrite absorbing powder and absorbing coating and corresponding products.

[0007] According to the first aspect of the present application, a method for preparing heteroionic dual-site modified barium ferrite wave absorbing powder is provided, the method comprising: Step 1: Preparation of modified barium ferrite absorbing powder precursor solution A mixed solution is prepared by using an acetate composition, a nitrate composition, a citrate and deionized water according to a ratio, and the pH of the mixed solution is adjusted by using an ammonium hydroxide solution to obtain a modified barium ferrite absorbing powder precursor solution; Step 2: Preparation of modified barium ferrite absorbing powder precursor The modified barium ferrite absorbing powder precursor solution is subjected to gelling treatment, and the gelling product is subjected to drying treatment to obtain the modified barium ferrite absorbing powder precursor; Step 3: Preparation of heteroion double-site modified barium ferrite microwave absorbing powder The modified barium ferrite absorbing powder precursor is subjected to combustion treatment, the combustion product is subjected to a first grinding treatment, the powder obtained by the first grinding treatment is subjected to a sintering heat treatment, and the sintering heat treatment product is subjected to a second grinding heat treatment to obtain hetero-ion dual-site modified barium ferrite absorbing powder.

[0008] Optionally, in the preparation method of the heteroionic dual-site modified barium ferrite absorbing powder of the present application, in step one, a mixed solution is prepared according to a ratio using an acetate composition, a nitrate composition, a citrate and deionized water, including: adding 0.7-0.99 weight parts of barium acetate, 11.4-11.8 weight parts of ferric acetate, 0.2-0.6 weight parts of zirconium nitrate, 0.01-0.3 weight parts of neodymium nitrate and 19 weight parts of citrate to 120 weight parts of deionized water, and magnetically stirring to obtain a mixed solution.

[0009] Optionally, the preparation method of the heteroionic dual-site modified barium ferrite absorbing powder of the present application, in step one, uses ammonium hydroxide solution to adjust the pH of the mixed solution to obtain a modified barium ferrite absorbing powder precursor solution, including: adding 35 parts by weight of ammonium hydroxide solution to the mixed solution to obtain a modified barium ferrite absorbing powder precursor solution.

[0010] Optionally, in the preparation method of the heteroionic dual-site modified barium ferrite absorbing powder of the present application, in step 2, the modified barium ferrite absorbing powder precursor solution is gelled, including: stirring the modified barium ferrite absorbing powder precursor solution at a temperature of 100° C. and a rotation speed of 500 rpm for 5 hours.

[0011] Optionally, in the method for preparing the heteroionic dual-site modified barium ferrite absorbing powder of the present application, in step 2, the drying temperature is 200° C. and the drying time is 36 hours.

[0012] Optionally, in the preparation method of the heteroionic dual-site modified barium ferrite absorbing powder of the present application, in step three, the modified barium ferrite absorbing powder precursor is subjected to a combustion treatment, and the combustion product is subjected to a first grinding treatment, including: heating the modified barium ferrite absorbing powder precursor to 450°C at a heating rate of 8°C / min, burning for 2 hours and then naturally cooling to obtain a combustion product, and subjecting the combustion product to a first grinding treatment of 60rpm×10min.

[0013] Optionally, in the preparation method of the heteroionic dual-site modified barium ferrite absorbing powder of the present application, in step three, the powder obtained by the first grinding treatment is subjected to sintering heat treatment, and the sintering heat treatment product is subjected to a second grinding heat treatment, including: heating the powder obtained by the first grinding treatment to 1200-1450°C at a heating rate of 8°C / min, keeping the temperature for 2-4h and then cooling it with the furnace to obtain a heat-treated product, and subjecting the heat-treated product to a second grinding treatment of 100rpm×120min.

[0014] According to the second aspect of the present application, a hetero-ionic double-site modified barium ferrite absorbing powder is provided. The hetero-ionic double-site modified barium ferrite absorbing powder is prepared according to the method of the first aspect.

[0015] According to a third aspect of the present application, a method for preparing an absorbing coating based on heteroionic dual-site modified barium ferrite absorbing powder is provided, the method comprising: Step 1: Raw material preparation The hetero-ion double-site modified barium ferrite absorbing powder was ball-milled for 16 hours at a ball-to-material ratio of 10:1 to obtain a ball-milled powder, and the ball-milled powder was washed with anhydrous ethanol and dried at 60° C. for 12 hours to obtain a raw material for an absorbing coating based on the hetero-ion double-site modified barium ferrite absorbing powder; Step 2: Absorbing coating based on heteroion double-site modified barium ferrite absorbing powder Piperazine, N,N-dimethylformamide, epoxy resin and absorbing coating materials based on heteroionic binary-modified barium ferrite absorbing powder are mixed in a weight ratio of 0.01:4:1:4, and ultrasonic and stirring treatment is performed for 2 hours to obtain a mixed slurry. The obtained mixed slurry is sprayed on a substrate using a 0.3-0.8 mm caliber spray gun, and naturally dried for 48 hours to obtain an absorbing coating based on heteroionic binary-modified barium ferrite absorbing powder.

[0016] According to the fourth aspect of the present application, a microwave absorbing coating based on heteroatom ion double-site modified barium ferrite microwave absorbing powder is provided. The microwave absorbing coating based on heteroatom ion double-site modified barium ferrite microwave absorbing powder is prepared according to the method of the third aspect above.

[0017] The preparation method of the hetero-ion double-site modified barium ferrite absorbing powder and absorbing coating and the corresponding products of the present application have the following beneficial technical effects: 1. By preparing heteroion double-site modified barium ferrite absorbing powder, the typical flaky structure of barium ferrite is changed. By controlling the doping amount, the flaky structure has edges and corners, or even a rounded shape without edges, making the morphology of barium ferrite more uniform, and improving the absorbing performance of heteroion double-site modified barium ferrite absorbing powder near the window; 2. Replace the Ba in the a position of barium ferrite by doping with a variety of relatively large ions 2+ and Fe at position b 3+ , improve the dielectric properties of barium ferrite materials at high frequencies, increase the attenuation constant, and make the material have excellent absorbing performance at a lower matching thickness. The heteroion double-site modified barium ferrite absorbing powder has a matching thickness of 0.74mm and the entire band is less than -10dB, and the maximum reflection loss is -58.70dB at 37.99GHz; 3. By controlling the amount of ion substitution in the system, the natural resonance peak of barium ferrite can be adjusted. By controlling the amount of high-valent ion substitution, the natural resonance peak of the hetero-ion double-site modified barium ferrite absorbing powder is controlled at around 35GHz, and a larger absorption bandwidth and higher absorption intensity are obtained; 4. By modifying the barium ferrite with heteroatom ions, its crystal structure and magnetocrystalline anisotropy are changed, the Curie temperature and high temperature stability of the material are increased, and the service range of the material is broadened. The prepared heteroatom ion-modified barium ferrite absorbing powder has a Curie temperature above 600K and is suitable for special service environments; 5. Based on the barium ferrite absorbing powder modified by heteroatom ions, the absorbing coating based on the barium ferrite absorbing powder modified by heteroatom ions is efficiently and economically prepared, which has a maximum reflection loss of -27.67dB at 35.44GHz, and the corresponding bandwidth reaches 5.25GHz; 6. The preparation method has the advantages of simple operation, conventional equipment, controllable cost and short process flow. The prepared heteroionic dual-site modified barium ferrite absorbing powder and its coating have broad application prospects in millimeter wave communication equipment, 5G base stations and electronic packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 X-ray diffraction patterns of the heteroionic double-site modified barium ferrite absorbing powders prepared in Examples 1, 2, 3, 4 and 5 of the present application; Figure 2 This is a SEM image of the heteroionic dual-site modified barium ferrite absorbing powder prepared in Example 1 of the present application; Figure 3 This is a SEM image of the heteroionic dual-site modified barium ferrite absorbing powder prepared in Example 2 of the present application; Figure 4 This is a SEM image of the heteroionic dual-site modified barium ferrite absorbing powder prepared in Example 3 of the present application; Figure 5 This is the MT curve of the hetero-ion double-site modified barium ferrite absorbing powder prepared in Example 3 of the present application; Figure 6 MT curve of the hetero-ion double-site modified barium ferrite absorbing powder prepared in Example 4 of the present application; Figure 7 This is a reflection loss curve of the hetero-ion double-site modified barium ferrite absorbing powder prepared in Example 1; Figure 8 This is a reflection loss curve of the hetero-ion dual-site modified barium ferrite absorbing powder prepared in Example 2; Fig. 9 This is a reflection loss curve of the hetero-ion dual-site modified barium ferrite absorbing powder prepared in Example 5; Fig.10 A reflection loss curve of the absorbing coating numbered a based on heteroionic dual-site modified barium ferrite absorbing powder prepared in Example 6 of the present application; Fig.11 A reflection loss curve of the absorbing coating numbered b based on heteroionic dual-site modified barium ferrite absorbing powder prepared in Example 6 of the present application; Fig.12 This is a reflection loss curve of the absorbing coating numbered c based on heteroionic dual-site modified barium ferrite absorbing powder prepared in Example 6 of the present application. DETAILED DESCRIPTION

[0020] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0021] It should be noted that the following embodiments and features in the embodiments may be combined with each other in the absence of conflict; and, based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making any creative work are within the scope of protection of the present disclosure.

[0022] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein may be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present disclosure, it should be understood by those skilled in the art that an aspect described herein may be implemented independently of any other aspect, and two or more of these aspects may be combined in various ways. For example, any number of aspects described herein may be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein may be used to implement this device and / or practice this method.

[0023] Example 1 Preparation of a kind of hetero-ion double-site modified barium ferrite microwave absorbing powder Step 1: Preparation of modified barium ferrite absorbing powder precursor solution 0.99 parts by weight of barium acetate, 11.7 parts by weight of ferric acetate, 0.3 parts by weight of zirconium nitrate, 0.01 parts by weight of neodymium nitrate and 19 parts by weight of citrate are added to 120 parts by weight of deionized water, and magnetic stirring is performed to obtain a mixed solution, and 35 parts by weight of ammonium hydroxide solution is added to the mixed solution to adjust the pH value, thereby obtaining a modified barium ferrite absorbing powder precursor solution; Step 2: Preparation of modified barium ferrite absorbing powder precursor The modified barium ferrite absorbing powder precursor solution is subjected to a gelling treatment. Specifically, the modified barium ferrite absorbing powder precursor solution is stirred at a temperature of 100° C. and a rotation speed of 500 rpm for 5 hours to obtain a gelling product; The gelled product was dried at a temperature of 200° C. for 36 hours to obtain a modified barium ferrite absorbing powder precursor. Step 3: Preparation of heteroion double-site modified barium ferrite microwave absorbing powder The modified barium ferrite absorbing powder precursor is subjected to combustion treatment, and the combustion product is subjected to a first grinding treatment. Specifically, the modified barium ferrite absorbing powder precursor is heated to 450° C. at a heating rate of 8° C. / min, and is naturally cooled after combustion for 2 hours to obtain a combustion product, and the combustion product is subjected to a first grinding treatment at 60 rpm×10 min; The powder obtained by the first grinding treatment is subjected to a sintering heat treatment, and the sintering heat treatment product is subjected to a second grinding heat treatment. Specifically, the powder obtained by the first grinding treatment is heated to 1200°C at a heating rate of 8°C / min, kept warm for 4 hours and then cooled with the furnace to obtain a heat-treated product. The heat-treated product is subjected to a second grinding treatment of 100rpm×120min to obtain anisotropic ion double-site modified barium ferrite absorbing powder.

[0024] Example 2 Preparation of a kind of hetero-ion double-site modified barium ferrite microwave absorbing powder Step 1: Preparation of modified barium ferrite absorbing powder precursor solution 0.7 parts by weight of barium acetate, 11.5 parts by weight of ferric acetate, 0.5 parts by weight of zirconium nitrate, 0.3 parts by weight of neodymium nitrate and 19 parts by weight of citrate are added to 120 parts by weight of deionized water, and magnetic stirring is performed to obtain a mixed solution, and 35 parts by weight of ammonium hydroxide solution is added to the mixed solution to adjust the pH value, so as to obtain a modified barium ferrite absorbing powder precursor solution; Step 2: Preparation of modified barium ferrite absorbing powder precursor The modified barium ferrite absorbing powder precursor solution is subjected to a gelling treatment. Specifically, the modified barium ferrite absorbing powder precursor solution is stirred at a temperature of 100° C. and a rotation speed of 500 rpm for 5 hours to obtain a gelling product; The gelled product was dried at a temperature of 200° C. for 36 hours to obtain a modified barium ferrite absorbing powder precursor. Step 3: Preparation of heteroion double-site modified barium ferrite microwave absorbing powder The modified barium ferrite absorbing powder precursor is subjected to combustion treatment, and the combustion product is subjected to a first grinding treatment. Specifically, the modified barium ferrite absorbing powder precursor is heated to 450° C. at a heating rate of 8° C. / min, and is naturally cooled after combustion for 2 hours to obtain a combustion product, and the combustion product is subjected to a first grinding treatment at 60 rpm×10 min; The powder obtained by the first grinding treatment is subjected to a sintering heat treatment, and the sintering heat treatment product is subjected to a second grinding heat treatment. Specifically, the powder obtained by the first grinding treatment is heated to 1300°C at a heating rate of 8°C / min, kept warm for 3.5 hours and then cooled with the furnace to obtain a heat-treated product. The heat-treated product is subjected to a second grinding treatment of 100rpm×120min to obtain anisotropic ion double-site modified barium ferrite absorbing powder.

[0025] Example 3 Preparation of a kind of hetero-ion double-site modified barium ferrite microwave absorbing powder Step 1: Preparation of modified barium ferrite absorbing powder precursor solution 0.75 parts by weight of barium acetate, 11.8 parts by weight of ferric acetate, 0.2 parts by weight of zirconium nitrate, 0.25 parts by weight of neodymium nitrate and 19 parts by weight of citrate are added to 120 parts by weight of deionized water, and magnetic stirring is performed to obtain a mixed solution, and 35 parts by weight of ammonium hydroxide solution is added to the mixed solution to adjust the pH value, thereby obtaining a modified barium ferrite absorbing powder precursor solution; Step 2: Preparation of modified barium ferrite absorbing powder precursor The modified barium ferrite absorbing powder precursor solution is subjected to a gelling treatment. Specifically, the modified barium ferrite absorbing powder precursor solution is stirred at a temperature of 100° C. and a rotation speed of 500 rpm for 5 hours to obtain a gelling product; The gelled product was dried at a temperature of 200° C. for 36 hours to obtain a modified barium ferrite absorbing powder precursor. Step 3: Preparation of heteroion double-site modified barium ferrite microwave absorbing powder The modified barium ferrite absorbing powder precursor is subjected to combustion treatment, and the combustion product is subjected to a first grinding treatment. Specifically, the modified barium ferrite absorbing powder precursor is heated to 450° C. at a heating rate of 8° C. / min, and is naturally cooled after combustion for 2 hours to obtain a combustion product, and the combustion product is subjected to a first grinding treatment at 60 rpm×10 min; The powder obtained by the first grinding treatment is subjected to a sintering heat treatment, and the sintering heat treatment product is subjected to a second grinding heat treatment. Specifically, the powder obtained by the first grinding treatment is heated to 1400°C at a heating rate of 8°C / min, kept warm for 3 hours and then cooled with the furnace to obtain a heat-treated product. The heat-treated product is subjected to a second grinding treatment of 100rpm×120min to obtain anisotropic ion double-site modified barium ferrite absorbing powder.

[0026] Example 4 Preparation of a kind of hetero-ion double-site modified barium ferrite microwave absorbing powder Step 1: Preparation of modified barium ferrite absorbing powder precursor solution 0.85 parts by weight of barium acetate, 11.6 parts by weight of ferric acetate, 0.4 parts by weight of zirconium nitrate, 0.15 parts by weight of neodymium nitrate and 19 parts by weight of citrate are added to 120 parts by weight of deionized water, and magnetic stirring is performed to obtain a mixed solution, and 35 parts by weight of ammonium hydroxide solution is added to the mixed solution to adjust the pH value, thereby obtaining a modified barium ferrite absorbing powder precursor solution; Step 2: Preparation of modified barium ferrite absorbing powder precursor The modified barium ferrite absorbing powder precursor solution is subjected to a gelling treatment. Specifically, the modified barium ferrite absorbing powder precursor solution is stirred at a temperature of 100° C. and a rotation speed of 500 rpm for 5 hours to obtain a gelling product; The gelled product was dried at a temperature of 200° C. for 36 hours to obtain a modified barium ferrite absorbing powder precursor. Step 3: Preparation of heteroion double-site modified barium ferrite microwave absorbing powder The modified barium ferrite absorbing powder precursor is subjected to combustion treatment, and the combustion product is subjected to a first grinding treatment. Specifically, the modified barium ferrite absorbing powder precursor is heated to 450° C. at a heating rate of 8° C. / min, and is naturally cooled after combustion for 2 hours to obtain a combustion product, and the combustion product is subjected to a first grinding treatment at 60 rpm×10 min; The powder obtained by the first grinding treatment is subjected to a sintering heat treatment, and the sintering heat treatment product is subjected to a second grinding heat treatment. Specifically, the powder obtained by the first grinding treatment is heated to 1450°C at a heating rate of 8°C / min, kept warm for 2.5 hours and then cooled with the furnace to obtain a heat-treated product. The heat-treated product is subjected to a second grinding treatment of 100rpm×120min to obtain anisotropic ion double-site modified barium ferrite absorbing powder.

[0027] Example 5 Preparation of a kind of hetero-ion double-site modified barium ferrite microwave absorbing powder Step 1: Preparation of modified barium ferrite absorbing powder precursor solution 0.85 parts by weight of barium acetate, 11.4 parts by weight of ferric acetate, 0.6 parts by weight of zirconium nitrate, 0.15 parts by weight of neodymium nitrate and 19 parts by weight of citrate are added to 120 parts by weight of deionized water, and magnetic stirring is performed to obtain a mixed solution, and 35 parts by weight of ammonium hydroxide solution is added to the mixed solution to adjust the pH value, so as to obtain a modified barium ferrite absorbing powder precursor solution; Step 2: Preparation of modified barium ferrite absorbing powder precursor The modified barium ferrite absorbing powder precursor solution is subjected to a gelling treatment. Specifically, the modified barium ferrite absorbing powder precursor solution is stirred at a temperature of 100° C. and a rotation speed of 500 rpm for 5 hours to obtain a gelling product; The gelled product was dried at a temperature of 200° C. for 36 hours to obtain a modified barium ferrite absorbing powder precursor. Step 3: Preparation of heteroion double-site modified barium ferrite microwave absorbing powder The modified barium ferrite absorbing powder precursor is subjected to combustion treatment, and the combustion product is subjected to a first grinding treatment. Specifically, the modified barium ferrite absorbing powder precursor is heated to 450° C. at a heating rate of 8° C. / min, and is naturally cooled after combustion for 2 hours to obtain a combustion product, and the combustion product is subjected to a first grinding treatment at 60 rpm×10 min; The powder obtained by the first grinding treatment is subjected to a sintering heat treatment, and the sintering heat treatment product is subjected to a second grinding heat treatment. Specifically, the powder obtained by the first grinding treatment is heated to 1200°C at a heating rate of 8°C / min, kept warm for 2 hours and then cooled with the furnace to obtain a heat-treated product. The heat-treated product is subjected to a second grinding treatment of 100rpm×120min to obtain anisotropic ion double-site modified barium ferrite absorbing powder.

[0028] Example 6 Preparation of microwave absorbing coating based on heteroion double-site modified barium ferrite microwave absorbing powder Step 1: Raw material preparation The hetero-ion double-site modified barium ferrite absorbing powder was ball-milled for 16 hours at a ball-to-material ratio of 10:1 to obtain a ball-milled powder, and the ball-milled powder was washed with anhydrous ethanol and dried at 60° C. for 12 hours to obtain a raw material for an absorbing coating based on the hetero-ion double-site modified barium ferrite absorbing powder; Step 2: Absorbing coating based on heteroion double-site modified barium ferrite absorbing powder Piperazine, N,N-dimethylformamide, epoxy resin and the absorbing coating material based on heteroatomized ion double-position modified barium ferrite absorbing powder were mixed in a weight ratio of 0.01:4:1:4, and ultrasonic and stirring treatment was performed for 2 hours to obtain a mixed slurry. The mixed slurry was sprayed on a substrate using a 0.3-0.8 mm caliber spray gun, and dried naturally for 48 hours to prepare absorbing coatings based on heteroatomized ion double-position modified barium ferrite absorbing powder numbered a, b and c, respectively. The relevant process parameters involved in the absorbing coatings based on heteroatomized ion double-position modified barium ferrite absorbing powder numbered a, b and c are shown in Table 1.

[0029] Table 1

[0030] Example 7 The phase composition of the hetero-ionic double-site modified barium ferrite absorbing powder prepared in Example 1, Example 2, Example 3, Example 4 and Example 5 was analyzed using an X-ray diffractometer of model PANalytical X-Pert PRO MPD. The powdered sample was poured into the groove of the glass slide to fill the groove, and then placed in the X-ray diffractometer. The ray source was Cu Kα (λ = 0.15406nm), the scanning range was 10-90°, the scanning rate was 10°C / min, the tube voltage was 20-60kV, and the tube current was 10-300mA. The test results are shown in Figure 1 .

[0031] Figure 1The X-ray diffraction patterns of the hetero-ion double-site modified barium ferrite absorbing powders prepared in Examples 1, 2, 3, 4 and 5 of the present application are shown in FIG. Figure 1 As shown, obvious characteristic peaks of barium ferrite appear at 30.31°, 32.19°, 34.11°, 37.07°, 40.31°, 54.97°, 56.55°, and 63.56°, corresponding to the (110), (107), (114), (203), (205), (217), (2011), and (2013) crystal planes, respectively, indicating that Examples 1, 2, 3, 4, and 5 of the present application successfully prepared heteroion double-site modified barium ferrite absorbing powder.

[0032] The microstructures of the heteroion-modified barium ferrite absorbing powders prepared in Example 1, Example 2, and Example 5 were observed using a cold field emission scanning electron microscope (SEM) of model Hitachi SU8020, with an accelerating voltage of 5 kV. The microstructures of the heteroion-modified barium ferrite absorbing powders prepared in Example 1, Example 2, and Example 5 are shown in FIG. Figure 2 , Figure 3 and Figure 4 .

[0033] Figure 2 This is a SEM image of the heteroionic dual-site modified barium ferrite wave absorbing powder prepared in Example 1 of the present application. Figure 3 This is a SEM image of the heteroionic dual-site modified barium ferrite absorbing powder prepared in Example 2 of the present application. Figure 4 This is a SEM image of the heteroionic double-site modified barium ferrite absorbing powder prepared in Example 3 of the present application, as shown in FIG. Figure 2 , Figure 3 and Figure 4 As shown, the hetero-ion double-position modified barium ferrite absorbing powder prepared by the present application presents a typical flat structure of barium ferrite. As the amount of ion substitution changes, the particles gradually become larger and have sharp edges or a rounded morphology without edges. These morphologies improve the absorbing performance of the hetero-ion double-position modified barium ferrite absorbing powder near the window. The present application changes the typical flaky structure of barium ferrite by preparing hetero-ion double-position modified barium ferrite absorbing powder, controls the doping amount, and controls the morphology of the material, so that the morphology of the barium ferrite is more uniform, thereby improving the absorbing performance of the hetero-ion double-position modified barium ferrite absorbing powder near the window.

[0034] The Curie temperature of the hetero-ion double-site modified barium ferrite absorbing powder prepared in Example 3 and Example 4 was tested by using a temperature and field control platform of model PPMS-9, a source meter of model KEITHLEY2400, and a nanovoltmeter of model KEITHLEY2182A, and a physical property comprehensive measurement system for collecting data using LABVIEW programming. The MT curves of the hetero-ion double-site modified barium ferrite absorbing powder prepared in Example 3 and Example 4 are shown in Figure 5 and Figure 6 .

[0035] The present application changes the crystal structure and magnetocrystalline anisotropy of barium ferrite by modifying it with heteroatom ions, thereby increasing the Curie temperature and high-temperature stability of the material and broadening the service range of the material. The prepared heteroatom ion-modified barium ferrite absorbing powder has a Curie temperature above 600K and is suitable for special service environments. Figure 5 This is the MT curve of the hetero-ion double-site modified barium ferrite absorbing powder prepared in Example 3 of the present application. Figure 6 This is the MT curve of the heteroionic dual-site modified barium ferrite absorbing powder prepared in Example 4 of the present application. Figure 5 and Figure 6 The upper part is the MT curve of the barium ferrite absorbing powder modified by hetero-ion di-site. Figure 5 and Figure 6 The lower part of is the curve obtained by taking the derivative of the upper MT curve. Figure 5 and Figure 6 As shown, the Curie temperature of the heteroionic double-site modified barium ferrite absorbing powder prepared in the present application is above 600K, and it can still maintain good magnetic properties at a relatively high temperature.

[0036] A ROHDE & SCHWARZ vector network analyzer was used to test the frequency range of 26.5-40 GHz using a waveguide method. The dielectric parameters of the hetero-ion double-site modified barium ferrite absorbing powder prepared in Example 1, Example 2 and Example 5 were tested respectively, and the reflection loss values ​​under different material thicknesses were calculated to obtain the reflection loss curves of the hetero-ion double-site modified barium ferrite absorbing powder prepared in Example 1, Example 2 and Example 5. The test results are shown in Table 1. Figure 7 , Figure 8 and Fig. 9 Specifically, the prepared heteroion double-site modified barium ferrite absorbing powder was pressed into a rectangular sheet by a mold, the applied pressure was 1.5-2MPa, the pressurization time was 30s, and the reflection loss performance graph of 26.5-40GHz was obtained by waveguide method testing.

[0037] Figure 7 This is a reflection loss curve of the hetero-ion double-site modified barium ferrite absorbing powder prepared in Example 1 of the present application. Figure 8This is a reflection loss curve of the hetero-ion double-site modified barium ferrite absorbing powder prepared in Example 2 of the present application. Fig. 9 This is a reflection loss curve of the heteroionic dual-site modified barium ferrite absorbing powder prepared in Example 5 of the present application.

[0038] The present invention replaces the Ba in the a position of barium ferrite by doping with a variety of relatively large ions. 2+ and Fe at position b 3+ , improve the dielectric properties of barium ferrite materials at high frequencies, increase the attenuation constant, and make the material have excellent absorbing performance at a lower matching thickness. The heteroion double-site modified barium ferrite absorbing powder has a matching thickness of 0.74mm, and the entire band is less than -10dB, and the maximum reflection loss is -58.70dB at 37.99GHz. Figure 7 As shown, when the matching thickness of the hetero-ion double-site modified barium ferrite absorbing powder prepared in Example 1 is 0.74 mm, the effective bandwidth is the entire frequency band, and the maximum reflection loss is -58.70 dB at 37.99 GHz. Figure 8 As shown, when the matching thickness of the hetero-ion double-site modified barium ferrite absorbing powder prepared in Example 2 is 0.66 mm, the maximum effective bandwidth is 7.59 GHz, and when the thickness is 0.58 mm, the maximum reflection loss is -17.31 dB at 39.43 GHz. Fig. 9 As shown, when the matching thickness of the hetero-ion dual-site modified barium ferrite absorbing powder prepared in Example 5 is 0.64 mm, the maximum effective bandwidth is 9.21 GHz, and at this time, the maximum reflection loss is -45.68 dB at 31.42 GHz.

[0039] The ROHDE & SCHWARZ vector network analyzer was used to test the frequency range of 26.5-40 GHz by waveguide method. The dielectric parameters of the absorbing coatings numbered a, b, and c prepared in Example 6 based on the heteroionic double-site modified barium ferrite absorbing powder were tested, and the reflection loss values ​​at different coating thicknesses were calculated. The test results are shown in Fig.10 , Fig.11 and Fig.12 Specifically, the prepared absorbing coating based on the hetero-ion double-site modified barium ferrite absorbing powder is cut into rectangular sheets suitable for waveguide method testing using a mold, with a thickness of no more than 1.2 mm, and a reflection loss performance graph of 26.5-40 GHz is obtained through waveguide method testing.

[0040] The present application achieves adjustable natural resonance peak of barium ferrite by controlling the amount of ion substitution in the system. By controlling the amount of high-valent ion substitution, the natural resonance peak of the hetero-ion double-site modified barium ferrite absorbing powder is controlled to be around 35 GHz, and a larger absorption bandwidth and higher absorption intensity are obtained. Fig.10 This is a reflection loss curve of the absorbing coating numbered a based on heteroionic dual-site modified barium ferrite absorbing powder prepared in Example 6 of the present application, Fig.11 This is a reflection loss curve of the absorbing coating numbered b based on heteroionic dual-site modified barium ferrite absorbing powder prepared in Example 6 of the present application, Fig.12 This is a reflection loss curve of the absorbing coating numbered c based on heteroion double-site modified barium ferrite absorbing powder prepared in Example 6 of the present application, as shown in FIG. Fig.10 , Fig.11 and Fig.12 As shown, the absorbing coating based on heteroionic dual-site modified barium ferrite absorbing powder prepared in the present application has excellent absorbing intensity and large effective bandwidth near the atmospheric window of 35 GHz.

[0041] like Fig.10 As shown, the absorbing coating numbered a based on heteroion double-site modified barium ferrite absorbing powder prepared in Example 6 of the present application has a maximum reflection loss of -27.67 dB at 35.44 GHz and an effective bandwidth of 5.25 GHz. Fig.11 As shown, the absorbing coating numbered b based on heteroion double-site modified barium ferrite absorbing powder prepared in Example 6 of the present application has a maximum reflection loss of -17.79 dB at 34.15 GHz and an effective bandwidth of 6.21 GHz. Fig.12 As shown, the absorbing coating numbered a based on heteroionic double-site modified barium ferrite absorbing powder prepared in Example 6 of the present application has a maximum reflection loss of -23.25 dB at 35.11 GHz and an effective bandwidth of 5.42 GHz.

[0042] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for preparing heteroion double-site modified barium ferrite wave absorbing powder, characterized in that: The method comprises: Step 1: Preparation of modified barium ferrite absorbing powder precursor solution A mixed solution is prepared by using an acetate composition, a nitrate composition, a citrate and deionized water according to a ratio, and the pH of the mixed solution is adjusted by using an ammonium hydroxide solution to obtain a modified barium ferrite absorbing powder precursor solution; Step 2: Preparation of modified barium ferrite absorbing powder precursor The modified barium ferrite absorbing powder precursor solution is subjected to gelling treatment, and the gelling product is subjected to drying treatment to obtain the modified barium ferrite absorbing powder precursor; Step 3: Preparation of heteroion double-site modified barium ferrite microwave absorbing powder The modified barium ferrite absorbing powder precursor is subjected to combustion treatment, the combustion product is subjected to a first grinding treatment, the powder obtained by the first grinding treatment is subjected to a sintering heat treatment, and the sintering heat treatment product is subjected to a second grinding heat treatment to obtain hetero-ion dual-site modified barium ferrite absorbing powder.

2. The method for preparing the heteroion double-site modified barium ferrite wave absorbing powder according to claim 1, characterized in that: In step 1, a mixed solution is prepared by using an acetate composition, a nitrate composition, a citrate and deionized water according to a ratio, including: adding 0.7-0.99 parts by weight of barium acetate, 11.4-11.8 parts by weight of ferric acetate, 0.2-0.6 parts by weight of zirconium nitrate, 0.01-0.3 parts by weight of neodymium nitrate and 19 parts by weight of citrate to 120 parts by weight of deionized water, and magnetically stirring to obtain a mixed solution.

3. The method for preparing the heteroion double-site modified barium ferrite wave absorbing powder according to claim 2, characterized in that: In step one, the pH of the mixed solution is adjusted using an ammonium hydroxide solution to obtain a modified barium ferrite absorbing powder precursor solution, including: adding 35 parts by weight of an ammonium hydroxide solution to the mixed solution to obtain a modified barium ferrite absorbing powder precursor solution.

4. The method for preparing the heteroion double-site modified barium ferrite wave absorbing powder according to claim 1, characterized in that: In step 2, the modified barium ferrite absorbing powder precursor solution is subjected to gelation treatment, including: stirring the modified barium ferrite absorbing powder precursor solution at a temperature of 100° C. and a rotation speed of 500 rpm for 5 hours.

5. The method for preparing the heteroion double-site modified barium ferrite wave absorbing powder according to claim 1, characterized in that: In step 2, the drying temperature is 200° C. and the drying time is 36 h.

6. The method for preparing the heteroion double-site modified barium ferrite wave absorbing powder according to claim 1, characterized in that: In step three, the modified barium ferrite absorbing powder precursor is subjected to a combustion treatment, and the combustion product is subjected to a first grinding treatment, including: heating the modified barium ferrite absorbing powder precursor to 450°C at a heating rate of 8°C / min, burning for 2 hours and then naturally cooling to obtain a combustion product, and subjecting the combustion product to a first grinding treatment at 60rpm×10min.

7. The method for preparing the heteroion double-site modified barium ferrite wave absorbing powder according to claim 1, characterized in that: In step three, the powder obtained by the first grinding treatment is subjected to a sintering heat treatment, and the sintering heat treatment product is subjected to a second grinding heat treatment, including: heating the powder obtained by the first grinding treatment to 1200-1450°C at a heating rate of 8°C / min, keeping it warm for 2-4 hours and then cooling it with the furnace to obtain a heat-treated product, and performing a second grinding treatment on the heat-treated product at 100rpm×120min.

8. A hetero-ion double-site modified barium ferrite microwave absorbing powder, characterized in that: The hetero-ion double-site modified barium ferrite wave-absorbing powder is prepared according to any one of the methods described in claims 1-6.

9. A method for preparing an absorbing coating based on heteroion double-site modified barium ferrite absorbing powder, characterized in that: The method comprises: Step 1: Raw material preparation The hetero-ion double-site modified barium ferrite absorbing powder was ball-milled for 16 hours at a ball-to-material ratio of 10:1 to obtain a ball-milled powder, and the ball-milled powder was washed with anhydrous ethanol and dried at 60° C. for 12 hours to obtain a raw material for an absorbing coating based on the hetero-ion double-site modified barium ferrite absorbing powder; Step 2: Absorbing coating based on heteroion double-site modified barium ferrite absorbing powder Piperazine, N,N-dimethylformamide, epoxy resin and absorbing coating materials based on heteroionic binary-modified barium ferrite absorbing powder are mixed in a weight ratio of 0.01:4:1:4, and ultrasonic and stirring treatment is performed for 2 hours to obtain a mixed slurry. The obtained mixed slurry is sprayed on a substrate using a 0.3-0.8 mm caliber spray gun, and naturally dried for 48 hours to obtain an absorbing coating based on heteroionic binary-modified barium ferrite absorbing powder.

10. A microwave absorbing coating based on heteroion double-site modified barium ferrite microwave absorbing powder, characterized in that: The microwave absorbing coating based on heteroionic dual-site modified barium ferrite microwave absorbing powder is prepared according to the method of claim 9.

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