Perovskite ceramic material, method for preparing the same and use thereof

Abstract

This invention belongs to the field of high-entropy ceramic materials technology, and discloses a perovskite ceramic material, its preparation method, and its application. The general chemical formula of the perovskite ceramic material of this invention is: (Ba y1 Sr y2 Ca y3 )Fe x O3, where x = 0.5–1.5, y1 = y2 = y3 = 0.2–0.4. The resulting perovskite-type ceramic material, when composited with paraffin at a mass ratio of 9:1 and a thickness of 1.2 mm, exhibits an absorption bandwidth of 4.16 GHz and a minimum reflection loss of -40.58 dB, demonstrating a wide effective absorption bandwidth and high absorption intensity even at low thicknesses. Furthermore, the material preparation method uses water as a solvent, eliminating the need for highly toxic chemical reagents, making it environmentally friendly and pollution-free. The preparation process is simple, low-cost, and suitable for large-scale industrial production.

Description

Technical Field

[0001] This invention relates to the field of high-entropy ceramic materials technology, and in particular to a perovskite-type ceramic material, its preparation method, and its application. Background Technology

[0002] Since the beginning of the 21st century, science and technology have developed rapidly, especially electronic information technology, bringing great convenience to people's lives and work. However, while bringing convenience, a large number of electronic products have also brought enormous harm. The excessive use of electronic products can lead to serious electromagnetic radiation and interference. Furthermore, the widespread application of electromagnetic waves in science and technology has also brought about a series of social problems, not only affecting communications but also directly or indirectly harming human health. Therefore, electromagnetic radiation has become another major source of pollution in the 21st century, following air pollution, water pollution, and light pollution. Meanwhile, with the in-depth development of precision-guided weapons, stealth weapons have become a key research project for the armaments of various countries.

[0003] Microwave-absorbing materials are key materials in both defense and civilian fields, including military stealth, microwave communication, and electromagnetic radiation protection. Absorbers with excellent absorption properties are the core of microwave-absorbing materials. To meet the requirements of thinness, lightness, width, and strength, research on absorbers is developing towards higher efficiency, composite materials, compatibility, and intelligentization.

[0004] Perovskite materials are microwave absorbing materials with strong dielectric loss and good stability, making them a promising candidate for this type of material. Yu Man et al. prepared Fe... 3+ Lanthanum nickelate perovskite ceramics, Fe 3+ The best absorption performance was achieved with a doping concentration of 0.05, with a matching thickness of 1.40 mm and a maximum peak value of -18.145 dB. The bandwidth below -10 dB was 1.42 GHz (9.38–10.8 GHz) (Journal of Aeronautical Materials, 2023, 43(06)). The team led by Che Renchao at Fudan University synthesized uniform BaTiO3 nanorings with concave and central pores using a hydrothermal method. The microwave absorption performance of BaTiO3 nanorings and solid BaTiO3 nanoparticles was tested in the 2–18 GHz microwave band. The maximum reflection loss of the BaTiO3 nanorings was -28.38 dB at 11.36 GHz and -12.87 dB at 16.32 GHz. The reflection loss increased by nearly 120% in the 8–12 GHz range (Nanoscale, 2011, 3(9):3860-3867). Cheng et al. used La 1-x Sr xThe composite of MnO3 and carbonyl iron enhances the polarization and magnetization of the material through the interface effect, resulting in a reflection loss of less than -10dB in the range of 2–18 GHz (Nature, 2020, 578(7794):251-260).

[0005] Current research on perovskite-type microwave absorbing materials mainly focuses on the doping of materials to construct composite microwave absorbing materials, but there is still a significant gap compared to the requirements for use in extreme environments. Summary of the Invention

[0006] The purpose of this invention is to provide a perovskite ceramic material, its preparation method, and its application, thereby solving the problem of poor performance of existing perovskite microwave absorbing materials in extreme environments.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] This invention provides a perovskite-type ceramic material, the chemical formula of which is: (Ba y1 Sr y2 Ca y3 )Fe x O3, where x = 0.5 to 1.5, y1 = y2 = y3 = 0.2 to 0.4.

[0009] This invention also provides a method for preparing perovskite-type ceramic materials, comprising the following steps:

[0010] By mixing strontium, barium, calcium, and iron sources with a precipitant and calcining, perovskite-type ceramic materials are obtained.

[0011] Preferably, in the preparation method, the strontium source includes strontium chloride and / or strontium nitrate; the barium source includes barium chloride and / or barium nitrate; the calcium source includes calcium chloride and / or calcium nitrate; and the iron source includes ferric nitrate and / or ferric chloride.

[0012] Preferably, in the preparation method, the precipitant comprises a mixture of sodium carbonate and an inorganic base;

[0013] The inorganic base includes sodium hydroxide and / or ammonia.

[0014] Preferably, in the preparation method, the mass ratio of sodium carbonate to inorganic alkali is 1-2:1-2.

[0015] Preferably, in the preparation method, the total mass ratio of the strontium source, barium source, calcium source, and iron source to the precipitant is 17-19:6-8.

[0016] Preferably, in the preparation method, the calcination temperature is 900-1300℃, the heating rate to the required calcination temperature is 4-6℃ / min, and the holding time after reaching the required calcination temperature is 3-5h.

[0017] Preferably, in the preparation method, the mixing of the strontium source, barium source, calcium source, iron source, and precipitant specifically involves:

[0018] Strontium source, barium source, calcium source, and iron source are mixed with water to obtain an inorganic salt solution; a precipitant is mixed with water to obtain a precipitant solution; the inorganic salt solution and the precipitant solution are mixed and then subjected to settling, filtration, washing, and drying in sequence.

[0019] In the inorganic salt solution, the ratio of the total mass of the strontium source, barium source, calcium source, and iron source to the volume of the water is 17-19 g: 90-110 mL.

[0020] In the precipitant solution, the mass ratio of the precipitant to the volume of the water is 6-8 g: 90-110 mL;

[0021] The stirring rate for mixing the inorganic salt solution and the precipitant solution is 500–800 r / min.

[0022] Preferably, in the preparation method, the inorganic salt solution and the precipitant solution are mixed by dropwise addition;

[0023] The dripping rate is 10–20 mL / min.

[0024] This invention also provides an application of perovskite ceramic materials in electromagnetic wave absorption.

[0025] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The perovskite-type ceramic material provided by this invention is (Ba y1 Sr y2 Ca y3 )Fe x O3, where x = 0.5 to 1.5, y1 = y2 = y3 = 0.2 to 0.4, and its mass ratio with paraffin is 9:1, with a thickness of 1.2 mm, can achieve an absorption bandwidth of 4.16 GHz and a minimum reflection loss of -40.58 dB. It has the characteristics of wide effective absorption bandwidth and high absorption intensity at low thickness.

[0027] (2) The present invention also provides a method for preparing the perovskite ceramic material, which uses water as a solvent, does not require the use of highly toxic chemical reagents, and is environmentally friendly and pollution-free; and the preparation process is simple and low in cost, and is suitable for large-scale industrial production. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0029] Figure 1 Here is a SEM image of the perovskite ceramic material from Example 1;

[0030] Figure 2 Here is a SEM image of the perovskite ceramic material from Example 2;

[0031] Figure 3 The reflection loss results for the perovskite ceramic material in Example 2 at a thickness of 1–5 mm are shown.

[0032] Figure 4 Here is a SEM image of the perovskite ceramic material from Example 3;

[0033] Figure 5 The XRD patterns are of the perovskite ceramic materials in Examples 1-3;

[0034] Figure 6 The reflection loss results are for the perovskite ceramic materials in Examples 1-3;

[0035] Figure 7 The impedance matching results are for the perovskite ceramic materials in Examples 1-3. Detailed Implementation

[0036] This invention provides a perovskite-type ceramic material, the chemical formula of which is: (Ba y1 Sr y2 Ca y3 )Fe x O3, where x = 0.5 to 1.5, y1 = y2 = y3 = 0.2 to 0.4.

[0037] In this invention, x in the general chemical formula is preferably 0.7 to 1.4, more preferably 0.8 to 1.1, and even more preferably 1.

[0038] In this invention, the chemical formula y1=y2=y3 is preferably 0.22~0.36, more preferably 0.29~0.34, and even more preferably 0.33.

[0039] In this invention, the particle size of the perovskite ceramic material is preferably 5-30 μm, more preferably 10-25 μm, and even more preferably 10-20 μm.

[0040] This invention also provides a method for preparing perovskite-type ceramic materials, comprising the following steps:

[0041] By mixing strontium, barium, calcium, and iron sources with a precipitant and calcining, perovskite-type ceramic materials are obtained.

[0042] In this invention, the preferred method for mixing the strontium source, barium source, calcium source, iron source, and precipitant is as follows:

[0043] Strontium source, barium source, calcium source, and iron source are mixed with water to obtain an inorganic salt solution; a precipitant is mixed with water to obtain a precipitant solution; the inorganic salt solution and the precipitant solution are mixed and then subjected to settling, filtration, washing, and drying in sequence.

[0044] In this invention, the ratio of the total mass of the strontium source, barium source, calcium source, and iron source to the volume of the water in the inorganic salt solution is preferably 17-19 g: 90-110 mL, more preferably 17.8-18.6 g: 95-105 mL, and even more preferably 18.3-18.4 g: 100 mL.

[0045] In this invention, the mass ratio of the precipitant to the volume of the water in the precipitant solution is preferably 6-8 g: 90-110 mL, more preferably 6.5-7.2 g: 95-105 mL, and even more preferably 6.7-6.8 g: 100 mL.

[0046] In this invention, the stirring rate for mixing the inorganic salt solution and the precipitant solution is preferably 500-800 r / min, more preferably 650-800 r / min, and even more preferably 700-750 r / min.

[0047] In this invention, the inorganic salt solution and the precipitant solution are preferably mixed by dropwise addition.

[0048] In this invention, the addition is preferably performed by adding an inorganic salt solution dropwise to a precipitant solution.

[0049] In this invention, the dripping rate is preferably 10-20 mL / min, more preferably 12-18 mL / min, and even more preferably 15-16 mL / min.

[0050] In this invention, the settling time is preferably 1 to 3 hours, more preferably 1.5 to 2.5 hours, and even more preferably 1.8 to 2.2 hours.

[0051] In this invention, the preferred filtration method is vacuum filtration.

[0052] In this invention, the equipment for filtration is preferably a vacuum filter machine.

[0053] In this invention, the washing reagent is preferably water and ethanol.

[0054] In this invention, the preferred washing method is to use water and ethanol sequentially.

[0055] In this invention, the target pH for washing is preferably 6.5 to 7.5, more preferably 6.7 to 7.3, and even more preferably 6.9 to 7.1.

[0056] In this invention, the drying temperature is preferably 100-110°C, more preferably 100-106°C, and even more preferably 100-102°C; the drying time is preferably 7-9 hours, more preferably 7.5-8.5 hours, and even more preferably 7.8-8.2 hours.

[0057] In this invention, the cooling method is preferably natural cooling.

[0058] In this invention, the target cooling temperature is preferably 20-30°C, more preferably 22-28°C, and even more preferably 24-26°C.

[0059] In this invention, the strontium source preferably includes strontium chloride and / or strontium nitrate, and more preferably strontium chloride (strontium chloride hexahydrate).

[0060] In this invention, the barium source preferably includes barium chloride and / or barium nitrate, and more preferably barium chloride (barium chloride dihydrate).

[0061] In this invention, the calcium source preferably includes calcium chloride and / or calcium nitrate, and more preferably calcium chloride.

[0062] In this invention, the iron source preferably includes ferric nitrate and / or ferric chloride, and more preferably ferric nitrate (ferric nitrate nonahydrate).

[0063] In this invention, the precipitant preferably comprises a mixture of sodium carbonate and an inorganic base. Using sodium carbonate and an inorganic base as precipitants allows for better precipitation of metal ions.

[0064] In this invention, the inorganic base preferably includes sodium hydroxide and / or ammonia, and more preferably sodium hydroxide.

[0065] In this invention, the mass ratio of sodium carbonate to inorganic alkali is preferably 1-2:1-2, more preferably 1-1.5:1-1.5, and even more preferably 1:1.13-1.14.

[0066] In this invention, the mass ratio of the total mass of the strontium source, barium source, calcium source, and iron source to the mass of the precipitant is preferably 17-19:6-8, more preferably 17.8-18.6:6.5-7.2, and even more preferably 18.3-18.4:6.7-6.8.

[0067] In this invention, the calcination temperature is preferably 900–1300°C, more preferably 1000–1200°C, and even more preferably 1100–1120°C; the heating rate to the desired calcination temperature is preferably 4–6°C / min, more preferably 4.5–5.5°C / min, and even more preferably 5–5.2°C / min; the holding time after reaching the desired calcination temperature is preferably 3–5 h, more preferably 3.5–4.5 h, and even more preferably 4–4.1 h.

[0068] In this invention, the calcination process preferably includes cooling.

[0069] In this invention, the cooling method is preferably natural cooling.

[0070] In this invention, the target cooling temperature is preferably 20-30°C, more preferably 22-28°C, and even more preferably 24-26°C.

[0071] This invention also provides an application of perovskite ceramic materials in electromagnetic wave absorption.

[0072] In this invention, the method of application is not limited, and any solution known to those skilled in the art can be used.

[0073] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0074] Example 1

[0075] This embodiment provides a perovskite-type ceramic material (Ca 0.33 Sr 0.33 Ba 0.33 The preparation method of FeO3 includes the following steps:

[0076] Weigh out 2.6662g of strontium chloride hexahydrate, 12.1197g of ferric nitrate nonahydrate, 1.1098g of calcium chloride and 2.4426g of barium chloride dihydrate and dissolve them together in 100mL of distilled water to obtain an inorganic salt solution;

[0077] Weigh out 3.6g of sodium hydroxide and 3.1797g of sodium carbonate and dissolve them in 100mL of distilled water to obtain a precipitant solution;

[0078] The inorganic salt solution was added dropwise to the precipitant solution at a rate of 15 mL / min while stirring at a stirring rate of 750 r / min. After the addition was complete, the mixture was allowed to stand for 2 h, then filtered by a vacuum filter. The precipitate was washed sequentially with distilled water and anhydrous ethanol until the pH of the precipitate was 7.0. The precipitate was then dried in a forced-air drying oven at 100 °C for 8 h and allowed to cool naturally to 24 °C to obtain the intermediate product.

[0079] The intermediate product was placed in a muffle furnace and heated to 1000°C at a rate of 5°C / min in air atmosphere. After calcination for 4 hours, it was naturally cooled to 25°C to obtain perovskite ceramic material.

[0080] The perovskite ceramic material prepared in Example 1 was analyzed by SEM, and the results are as follows: Figure 1 As shown. By Figure 1 It can be seen that the sample morphology is lamellar, approximately hexagonal, and the particle size is 15-20 μm.

[0081] Example 2

[0082] This embodiment provides a perovskite-type ceramic material (Ca 0.33 Sr 0.33 Ba 0.33 The preparation method of FeO3 differs from that of Example 1 in that the calcination temperature is modified to 1100℃, while other parameters and conditions are the same as in Example 1.

[0083] The perovskite ceramic material prepared in Example 2 was analyzed by SEM, and the results are as follows: Figure 2 As shown. By Figure 2 It can be seen that the sample morphology is a hexagonal layered structure with a particle size of about 5 μm.

[0084] The perovskite ceramic material prepared in Example 2 was subjected to reflection loss testing at thicknesses of 1–5 mm, and the results are as follows: Figure 3 As shown. By Figure 3 It can be seen that the ceramic product prepared in Example 2 has effective electromagnetic wave absorption performance in the thickness range of 1 to 5 mm, and its effective absorption bandwidth can effectively cover 2 to 18 GHz.

[0085] Example 3

[0086] This embodiment provides a perovskite-type ceramic material (Ca 0.33 Sr 0.33 Ba 0.33 The preparation method of FeO3 differs from that of Example 1 in that the calcination temperature is modified to 1200℃, while other parameters and conditions are the same as in Example 1.

[0087] The perovskite ceramic material prepared in Example 3 was analyzed by SEM, and the results are as follows: Figure 4 As shown. By Figure 4It can be seen that the sample particles gradually increase in size, with a particle size of 20–30 μm.

[0088] X-ray diffraction analysis was performed on the perovskite ceramic materials prepared in Examples 1-3, and the results are as follows: Figure 5 As shown. By Figure 5 It is known that perovskite-type ceramic materials have a non-perovskite second phase at a calcination temperature of 1000℃. The second phase peak disappears at 1100℃, forming a single phase. The second phase diffraction peak reappears at 1200℃.

[0089] The perovskite ceramic materials prepared in Examples 1-3 were compounded with paraffin at a mass ratio of 9:1, and the reflection loss was analyzed at a thickness of 1.2 mm. The results are as follows: Figure 6 As shown. By Figure 6 It is known that perovskite ceramic materials exhibit excellent electromagnetic wave absorption performance at a calcination temperature of 1100℃, with a minimum reflectivity of -40.58dB and an effective absorption bandwidth of 4.16GHz. Calcination temperatures that are too low (1000℃) or too high (1200℃) are detrimental to improving the electromagnetic wave absorption performance of the material.

[0090] The perovskite ceramic materials prepared in Examples 1-3 were compounded with paraffin at a mass ratio of 9:1, and impedance matching tests were performed at a thickness of 1.2 mm. The results are as follows. Figure 7 As shown. By Figure 7 It can be seen that the wave impedance matching characteristics are excellent at calcination temperatures of 1100℃ and 1200℃, while the wave impedance matching characteristics are poor at 1000℃.

[0091] As can be seen from the above embodiments, the perovskite ceramic material provided by the present invention has both dielectric loss and magnetic loss properties. When it is compounded with paraffin at a mass ratio of 9:1 and the thickness is 1.2mm, the effective absorption bandwidth can reach 4.16GHz and the minimum reflection loss can reach -40.58dB. It has the characteristics of wide effective absorption bandwidth and high absorption intensity at low thickness.

[0092] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a perovskite-type ceramic material, characterized in that, Includes the following steps: Strontium source, barium source, calcium source, iron source and precipitant are mixed and calcined to obtain perovskite ceramic material; The calcination temperature is 1100~1200℃, the heating rate to the required calcination temperature is 4~6℃ / min, and the holding time after reaching the required calcination temperature is 3~5h. The general chemical formula of the perovskite-type ceramic material is: (Ba y1 Sr y2 Ca y3 )Fe x O3, where x=1, y1=y2=y3=0.

33.

2. The preparation method according to claim 1, characterized in that, The strontium source includes strontium chloride and / or strontium nitrate; the barium source includes barium chloride and / or barium nitrate; the calcium source includes calcium chloride and / or calcium nitrate; and the iron source includes ferric nitrate and / or ferric chloride.

3. The preparation method according to claim 1, characterized in that, The precipitant comprises a mixture of sodium carbonate and an inorganic base; The inorganic base includes sodium hydroxide and / or ammonia.

4. The preparation method according to claim 3, characterized in that, The mass ratio of sodium carbonate to inorganic base is 1~2:1~2.

5. The preparation method according to any one of claims 1 to 3, characterized in that, The total mass ratio of the strontium source, barium source, calcium source, and iron source to the mass ratio of the precipitant is 17~19:6~8.

6. The preparation method according to claim 1, characterized in that, The specific method of mixing the strontium source, barium source, calcium source, iron source, and precipitant is as follows: Strontium source, barium source, calcium source, and iron source are mixed with water to obtain an inorganic salt solution; a precipitant is mixed with water to obtain a precipitant solution; the inorganic salt solution and the precipitant solution are mixed and then subjected to settling, filtration, washing, and drying in sequence. In the inorganic salt solution, the ratio of the total mass of the strontium source, barium source, calcium source, and iron source to the volume of the water is 17~19g:90~110mL; In the precipitant solution, the mass ratio of the precipitant to the volume of the water is 6~8g:90~110mL; The stirring rate for mixing the inorganic salt solution and the precipitant solution is 500~800 r / min.

7. The preparation method according to claim 6, characterized in that, The inorganic salt solution and the precipitant solution are mixed by dropwise addition; The dripping rate is 10~20 mL / min.

8. A perovskite-type ceramic material prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the perovskite ceramic material according to claim 8 in electromagnetic wave absorption.

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