A perovskite-type ceramic material, its preparation method and application

Abstract

The present invention belongs to the technical field of high-entropy ceramic materials, and provides a perovskite-type ceramic material, a preparation method and an application thereof. The ceramic material is Sr x (Cr y Mn y Fe y Co y Ni y )O3; x is 0.5 to 1.5, and y is 0.1 to 0.3. When the perovskite-type ceramic material provided by the present invention is compounded with paraffin according to a mass ratio of 4:1 and has a thickness of 2.8 mm, the absorption bandwidth can reach 2 GHz, and the lowest reflection loss can reach -43.17 dB, having the characteristics of wide effective absorption bandwidth and high absorption intensity at low thickness. The present invention also provides a preparation method of the perovskite-type ceramic material, which comprises the following steps: mixing an inorganic salt solution and a precipitating agent solution and then calcining to obtain the perovskite-type ceramic material. The present invention uses water as a solvent, does not need to use highly toxic chemical reagents, is environmentally friendly and pollution-free; and has a simple preparation process and low cost, and is suitable for large-scale industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of high-entropy ceramic materials, and particularly to a perovskite-type ceramic material, a preparation method thereof, and an application thereof. Background Art

[0002] Since the 21st century, science and technology have developed rapidly, especially electronic information technology, which has brought great convenience to our lives and work. However, the excessive use of electronic products will lead to serious electromagnetic radiation and interference, and the extensive application of electromagnetic waves in science and technology has also brought a series of social problems. At the same time, with the in-depth development of precision-guided weapons, stealth weapons have become the key research projects of the military equipment of various countries. Absorbing materials are one of the key materials in national defense and civilian fields such as military stealth, microwave communication, and electromagnetic radiation protection. Absorbents with good wave absorption performance are the core of absorbing materials. To meet the requirements of their thin, light, wide, and strong properties, the research on absorbents is also developing towards high efficiency, compounding, compatibility, and intelligence.

[0003] Perovskite materials are a type of wave-absorbing material with strong dielectric loss and have good stability. They are a type of dielectric loss-type wave-absorbing material that has received much attention. Le Chen et al. from Nanjing Tech University developed a new type of high-temperature radar stealth material through carbon nanotube Sm 0.5 Sr 0.5 CoO 3 perovskite materials, which have a relatively wide absorption band, but the highest peak value of their wave absorption data is greater than -10 dB; the team of Renchao Che from Fudan University prepared BaTiO 3 nanowires by hydrothermal method, with a minimum reflection loss of -24.6 dB at 9.04 GHz and an effective absorption bandwidth of 2.4 GHz. At present, the research on perovskite-type wave-absorbing materials mainly focuses on doping the materials to construct composite wave-absorbing materials, but it cannot simultaneously meet the current requirements of "thin, wide, light, and strong" for wave-absorbing materials. Summary of the Invention

[0004] The purpose of the present invention is to provide a perovskite-type ceramic material, a preparation method thereof, and an application thereof.

[0005] To achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a perovskite-type ceramic material, and the ceramic material is Sr x (Cr y Mn y Fe y Co y Ni y )O 3 ;

[0007] Where x is 0.5 to 1.5 and y is 0.1 to 0.3.

[0008] The present invention also provides a method for preparing the perovskite-type ceramic material, comprising the following steps:

[0009] Mix an inorganic salt solution and a precipitant solution and then calcine to obtain the perovskite-type ceramic material.

[0010] Preferably, the mass-volume ratio of the inorganic salt to water in the inorganic salt solution is 4 to 6 g: 40 to 60 mL; the inorganic salt includes strontium chloride hexahydrate, chromium chloride hexahydrate, manganese chloride tetrahydrate, iron nitrate nonahydrate, cobalt nitrate hexahydrate, and nickel nitrate hexahydrate.

[0011] Preferably, the mass-volume ratio of the precipitant to water in the precipitant solution is 2.5 to 3.5 g: 40 to 60 mL; the precipitant includes sodium carbonate and sodium hydroxide; the mass ratio of sodium carbonate to sodium hydroxide is 1 to 2: 1 to 2.

[0012] Preferably, the mass ratio of the inorganic salt to the precipitant is 4 to 6: 2.5 to 3.5.

[0013] Preferably, the mixing method is dropwise addition; the dropping rate is 12 to 18 mL / min.

[0014] Preferably, the calcination temperature is 1100 to 1350 °C, the heating rate of the calcination is 4 to 6 °C / min, and the holding time after reaching the calcination temperature is 3 to 5 h.

[0015] The present invention also provides an application of the ceramic material in absorbing electromagnetic waves.

[0016] The present invention has the following beneficial effects:

[0017] The present invention provides a perovskite-type ceramic material, which is Sr x (Cr y Mn y Fe y Co y Ni y )O 3 , where x is 0.5 to 1.5 and y is 0.1 to 0.3. When the mass ratio of the perovskite-type ceramic material provided by the present invention to paraffin is 4:1 and the thickness is 2.8 mm, the absorption bandwidth can reach 2 GHz, and the lowest reflection loss can reach -43.17 dB, having the characteristics of a wide effective absorption bandwidth and high absorption intensity at a low thickness.

[0018] The present invention also provides a method for preparing the perovskite-type ceramic material, which comprises the following steps: mixing an inorganic salt solution with a precipitant solution and then calcining to obtain the perovskite-type ceramic material. The present invention uses water as a solvent, does not require the use of highly toxic chemical reagents, is environmentally friendly and pollution-free; and the preparation process is simple and the cost is low, which is suitable for large-scale industrial production. Description of the Drawings

[0019] Figure 1 SEM image of the perovskite-type ceramic material prepared in Example 1;

[0020] Figure 2 SEM image of the perovskite-type ceramic material prepared in Example 2;

[0021] Figure 3 SEM image of the perovskite-type ceramic material prepared in Example 3;

[0022] Figure 4 SEM image of the perovskite-type ceramic material prepared in Example 4;

[0023] Figure 5 Reflection loss diagram of the perovskite-type ceramic material prepared in Example 4 at a thickness of 1 - 5 mm;

[0024] Figure 6 SEM image of the perovskite-type ceramic material prepared in Example 5;

[0025] Figure 7 X-ray diffraction diagram of the perovskite-type ceramic materials prepared in Examples 1 - 5;

[0026] Figure 8 Reflection loss diagram of the composite of the perovskite-type ceramic materials prepared in Examples 1 - 5 and paraffin with a mass ratio of 4:1 at a thickness of 2.8 mm;

[0027] Figure 9 Impedance matching diagram of the composite of the perovskite-type ceramic materials prepared in Examples 1 - 5 and paraffin with a mass ratio of 4:1 at a thickness of 2.8 mm. Detailed Description of the Invention

[0028] The present invention provides a perovskite-type ceramic material, and the ceramic material is Sr x (Cr y Mn y Fe y Co y Ni y )O 3 ; wherein x is 0.5 - 1.5 and y is 0.1 - 0.3.

[0029] In the present invention, x is preferably from 0.7 to 1.3, more preferably from 0.8 to 1.2, and even more preferably from 0.9 to 1.1; y is preferably 0.2.

[0030] In the present invention, the particle size of the perovskite-type ceramic material is preferably from 0.8 to 1.0 µm, more preferably from 0.85 to 0.95 µm, and even more preferably from 0.88 to 0.92 µm.

[0031] The present invention also provides a method for preparing the perovskite-type ceramic material, comprising the following steps: mixing an inorganic salt solution and a precipitant solution and then calcining to obtain the perovskite-type ceramic material.

[0032] In the present invention, the mass-volume ratio of the inorganic salt to water in the inorganic salt solution is preferably 4 - 6 g: 40 - 60 mL, more preferably 4.5 - 5.5 g: 45 - 55 mL, and even more preferably 4.8 - 5.2 g: 48 - 52 mL.

[0033] In the present invention, the inorganic salt preferably comprises strontium chloride hexahydrate, chromium chloride hexahydrate, manganese chloride tetrahydrate, iron nitrate nonahydrate, cobalt nitrate hexahydrate, and nickel nitrate hexahydrate.

[0034] In the present invention, the method for preparing the inorganic salt solution comprises the following steps: dissolving the inorganic salt in water to obtain the inorganic salt solution.

[0035] In the present invention, the mass-volume ratio of the precipitant to water in the precipitant solution is preferably 2.5 - 3.5 g: 40 - 60 mL, more preferably 2.7 - 3.3 g: 45 - 55 mL, and even more preferably 2.9 - 3.1 g: 48 - 52 mL.

[0036] In the present invention, the precipitant preferably comprises sodium carbonate and sodium hydroxide; the mass ratio of sodium carbonate to sodium hydroxide is preferably 1 - 2: 1 - 2, more preferably 1.2 - 1.8: 1.2 - 1.8, and even more preferably 1.4 - 1.6: 1.4 - 1.6.

[0037] In the present invention, using sodium carbonate and sodium hydroxide as the precipitant can make metal ions precipitate better.

[0038] In the present invention, the method for preparing the precipitant solution comprises the following steps: dissolving sodium carbonate and sodium hydroxide in water to obtain the precipitant solution.

[0039] In the present invention, the mass ratio of the inorganic salt to the precipitant is preferably 4 - 6: 2.5 - 3.5, more preferably 4.2 - 5.8: 2.7 - 3.3, and even more preferably 4.4 - 5.6: 2.9 - 3.1.

[0040] In the present invention, the mixing method is preferably dropwise addition; the precipitant solution is dropped into the inorganic salt solution; the dropping rate is preferably 12-18 mL / min, more preferably 13-17 mL / min, and still more preferably 14-16 mL / min.

[0041] In the present invention, continuous stirring is carried out during the dropping process, and the stirring rate is preferably 700-800 r / min, more preferably 720-780 r / min, and still more preferably 740-760 r / min.

[0042] In the present invention, after the dropping of the precipitant solution is completed, stirring, standing, filtering, washing, drying are carried out, and then calcination is carried out after cooling.

[0043] In the present invention, the stirring rate is preferably 700-800 r / min, more preferably 720-780 r / min, and still more preferably 740-760 r / min; the stirring time is preferably 20-30 min, more preferably 22-28 min, and still more preferably 24-26 min; the standing time is preferably 1-3 h, more preferably 1.5-2.5 h, and still more preferably 1.8-2.2 h; the filtering method is preferably suction filtration by a suction filter; the washing reagent is preferably distilled water and absolute ethanol; the washing method is preferably washing with distilled water and absolute ethanol in sequence; the target pH of the washing is preferably 6.5-7.5, more preferably 6.7-7.3, and still more preferably 6.9-7.1; the drying temperature is preferably 100-110 °C, more preferably 102-108 °C, and still more preferably 104-106 °C, the drying time is preferably 7-9 h, more preferably 7.5-8.5 h, and still more preferably 7.8-8.2 h; the cooling method is preferably natural cooling, and the target temperature of the cooling is preferably 20-30 °C, more preferably 22-28 °C, and still more preferably 24-26 °C.

[0044] In the present invention, the calcination temperature is preferably 1100-1350 °C, more preferably 1150-1300 °C, and still more preferably 1200-1250 °C, the heating rate of the calcination is preferably 4-6 °C / min, more preferably 4.5-5.5 °C / min, and still more preferably 4.8-5.2 °C / min, and the holding time after reaching the calcination temperature is preferably 3-5 h, more preferably 3.5-4.5 h, and still more preferably 3.8-4.2 h.

[0045] In the present invention, the perovskite-type ceramic material is obtained after cooling the calcined product.

[0046] In the present invention, the cooling method is preferably natural cooling, and the target temperature for cooling is preferably 20 - 30 °C, more preferably 22 - 28 °C, and even more preferably 24 - 26 °C.

[0047] The present invention also provides the application of the ceramic material in absorbing electromagnetic waves.

[0048] The technical solutions provided by the present invention will be described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention. Example 1

[0049] Weigh 2.6662 g of strontium chloride hexahydrate, 0.5329 g of chromium chloride hexahydrate, 0.3958 g of manganese chloride tetrahydrate, 0.808 g of iron nitrate nonahydrate, 0.5821 g of cobalt nitrate hexahydrate and 0.5816 g of nickel nitrate hexahydrate and dissolve them together in 50 mL of distilled water to obtain an inorganic salt solution. Weigh 1.44 g of sodium hydroxide and 1.59 g of sodium carbonate and dissolve them in 50 mL of distilled water to prepare a precipitant solution.

[0050] Drop the above precipitant solution into the inorganic salt solution at a rate of 15 mL / min, stir at a rate of 750 r / min during the dropping process. After the dropping is completed, continue to stir for 25 min at the same stirring rate and then let it stand for 2 h. Filter it with a suction filter, wash it successively with distilled water and absolute ethanol until the pH of the precipitate is 7.0, and then put it into a blast drying oven and dry it at 100 °C for 8 h, and naturally cool it to 24 °C to obtain an intermediate product.

[0051] Put the intermediate product into a muffle furnace and calcine it in an air atmosphere at a heating rate of 5 °C / min. After calcining at 1150 °C for 4 h, naturally cool it to 25 °C, and then obtain Sr(Cr 0.2 Mn 0.2 Fe 0.2 Co 0.2 N i0.2 )O 3 .

[0052] Perform SEM analysis on the perovskite-type ceramic material prepared in Example 1, and the results are as Figure 1 shown. Example 2

[0053] The only difference from Example 1 is that the calcination temperature is 1200 °C, and the remaining reaction conditions are the same as those in Example 1.

[0054] Perform SEM analysis on the perovskite-type ceramic material prepared in Example 2, and the results are as Figure 2 shown. Example 3

[0055] The only difference from Example 1 is that the calcination temperature is 1250 °C, and the remaining reaction conditions are the same as those in Example 1.

[0056] The perovskite-type ceramic material prepared in this Example 3 was subjected to SEM analysis, and the results are as Figure 3 shown. Example 4

[0057] The only difference from Example 1 is that the calcination temperature is 1300 °C, and the remaining reaction conditions are the same as those in Example 1.

[0058] The perovskite-type ceramic material prepared in this Example 4 was subjected to SEM analysis, and the results are as Figure 4 shown.

[0059] The perovskite-type ceramic material prepared in this Example was subjected to reflection loss testing at a thickness of 1 - 5 mm, and the results are as Figure 5 shown. It can be Figure 5 seen that the ceramic product prepared in this Example has effective electromagnetic wave absorption performance in the thickness range of 1 - 5 mm, and its effective wave absorption bandwidth can effectively cover 3 - 18 GHz. Example 5

[0060] The only difference from Example 1 is that the calcination temperature is 1350 °C, and the remaining reaction conditions are the same as those in Example 1.

[0061] The perovskite-type ceramic material prepared in this Example 5 was subjected to SEM analysis, and the results are as Figure 6 shown.

[0062] The perovskite-type ceramic materials prepared in Examples 1 - 5 were subjected to X-ray diffraction analysis, and the results are as Figure 7 shown. It can be Figure 7 seen that at a calcination temperature of 1150 °C, the perovskite-type ceramic material has a second phase with a non-perovskite structure; when the temperature is 1200 °C, the number of diffraction peaks of the second phase becomes weaker and decreases; when the temperature rises to 1250 - 1300 °C, the intensity of the second phase peaks further decreases. As the calcination temperature reaches 1350 °C, the second phase peaks disappear and a single phase is formed.

[0063] After the perovskite-type ceramic materials prepared in Examples 1 - 5 were compounded with paraffin at a ratio of 4:1, reflection loss analysis was carried out at a thickness of 2.8 mm, and the results are as Figure 8 shown. It can be Figure 8It can be seen that excellent electromagnetic wave absorption performance is exhibited at a calcination temperature of 1300 °C, with the lowest reflectivity reaching -43.17 dB and the effective absorption bandwidth reaching 1.78 GHz (6.24 - 8.02 GHz). Too low (1150 °C) or too high (1350 °C) calcination temperature is not conducive to improving the electromagnetic wave absorption performance of the material.

[0064] After compounding the perovskite-type ceramic materials prepared in Examples 1 - 5 with paraffin at a ratio of 4:1, impedance matching tests were carried out at a thickness of 2.8 mm, and the results are as Figure 9 shown. It can be Figure 9 seen that excellent wave impedance matching characteristics are exhibited at calcination temperatures of 1200 °C, 1250 °C, and 1300 °C, while the wave impedance matching characteristics at 1150 °C and 1350 °C are poor.

[0065] From the above examples, it can be seen that the present invention provides a perovskite-type ceramic material, and the ceramic material is Sr x (Cr y Mn y Fe y Co y Ni y )O 3 ; where x is 0.5 - 1.5 and y is 0.1 - 0.3. It can be seen from the examples that the perovskite-type ceramic material prepared by the present invention has both dielectric loss and magnetic loss properties. When compounded with paraffin at a ratio of 4:1 and a thickness of 2.8 mm, the effective absorption bandwidth can reach 2 GHz, and the lowest reflection loss can reach -43.17 dB; it has the characteristics of having an effective absorption bandwidth and high absorption intensity at a low thickness.

[0066] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A perovskite-type ceramic material, characterized in that, The ceramic material is Sr x (Cr y Mn y Fe y Co y Ni y )O 3 ; where x is 1 and y is 0.2; The preparation method of the perovskite-type ceramic material comprises the following steps: mixing an inorganic salt solution and a precipitant solution and then calcining to obtain the perovskite-type ceramic material; the mixing method is dropwise addition; dropping the precipitant solution into the inorganic salt solution; After the addition of the precipitant solution is completed, stir, stand, filter, wash, dry, cool and then calcine; The calcination temperature is 1200-1300 °C, the heating rate of the calcination is 4-6 °C / min, and the holding time after reaching the calcination temperature is 3-5 h.

2. The preparation method of the perovskite-type ceramic material according to claim 1, characterized in that, comprises the following steps: Mixing an inorganic salt solution and a precipitant solution and then calcining to obtain the perovskite-type ceramic material; The mixing method is dropwise addition; dropping the precipitant solution into the inorganic salt solution; After the addition of the precipitant solution is completed, stir, stand, filter, wash, dry, cool and then calcine; The calcination temperature is 1200-1300 °C, the heating rate of the calcination is 4-6 °C / min, and the holding time after reaching the calcination temperature is 3-5 h.

3. The preparation method according to claim 2, characterized in that, The mass-volume ratio of the inorganic salt to water in the inorganic salt solution is 4-6 g: 40-60 mL; The inorganic salt comprises strontium chloride hexahydrate, chromium chloride hexahydrate, manganese chloride tetrahydrate, iron nitrate nonahydrate, cobalt nitrate hexahydrate and nickel nitrate hexahydrate.

4. The preparation method according to claim 2 or 3, characterized in that, The mass-volume ratio of the precipitant to water in the precipitant solution is 2.5-3.5 g: 40-60 mL; The precipitant comprises sodium carbonate and sodium hydroxide; The mass ratio of the sodium carbonate to the sodium hydroxide is 1-2: 1-2.

5. The preparation method according to claim 4, characterized in that, The mass ratio of the inorganic salt to the precipitant is 4-6: 2.5-3.

5.

6. The preparation method according to claim 5, characterized in that, The dropping rate is 12-18 mL / min.

7. The application of the ceramic material according to claim 1 in absorbing electromagnetic waves.

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