Perovskite high-entropy ceramic material and preparation method and application thereof

Abstract

This invention discloses a perovskite-type high-entropy ceramic material, its preparation method, and its application. The preparation method of the perovskite-type high-entropy ceramic material of this invention includes the following steps: 1) mixing A-site oxide powder and B-site oxide powder and wet ball milling, followed by drying and grinding to obtain a mixed powder; 2) adding the mixed powder into a graphite crucible and compacting it, then subjecting it to laser radiation heating to obtain the perovskite-type high-entropy ceramic material. The perovskite-type high-entropy ceramic material of this invention exhibits multi-band absorption characteristics, high service temperature, and stable performance at high temperatures, making it suitable for use in stealth coatings for aerospace vehicles. Furthermore, its preparation method is simple, with a short reaction time and low production cost, making it suitable for large-scale industrial production and application.

Description

Technical Field

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

[0002] High-entropy perovskite ceramics are a novel type of ceramic material that combines the design concept of high entropy with the unique crystal structure of perovskite. They possess advantages such as high dielectric constant, high melting point, and good resistance to high-temperature oxidation, making them promising for applications in high-temperature microwave absorbing agents and microwave absorbing coatings for aerospace vehicles. However, existing high-entropy perovskite ceramics suffer from low electromagnetic loss, resulting in less than ideal microwave absorption performance. They can only effectively absorb microwaves in a single band (X-band), with a generally narrow effective absorption bandwidth, making it difficult to achieve multi-band electromagnetic stealth (e.g., X-band and Ku-band). Furthermore, they exhibit almost no microwave absorption performance at high temperatures. For example, Pang et al. prepared A-site high-entropy perovskite (Y-site high-entropy perovskite...) 0.2 La 0.2 Sm 0.2 Nd 0.2 Gd 0.2 CoO3 has an effective absorption bandwidth of 3.28 GHz at room temperature (covering 78% of the X-band), while its effective absorption bandwidth at 300 °C is 1.55 GHz (High-entropy perovskite (Y)). 0.2 La 0.2 Sm 0.2 Nd 0.2 Gd 0.2 (CoO3 with dielectric-conductive synergy achieving wide-temperature-range EMI shielding and electromagnetic wave absorption compatibility, JiaB Ma, YuP Duan and HuiFPang. Chemical Engineering Journal, 2025, 15, 520) can only effectively absorb in the X-band, has a low service temperature, and its absorption performance degrades severely at high temperatures (effective absorption bandwidth shrinks by about 52.7%). In addition, its preparation cycle is long (>12h), which greatly limits its practical application.

[0003] Therefore, it is of great significance to develop a high-entropy perovskite ceramic material that can be synthesized rapidly, has multi-band absorption characteristics, high service temperature, and stable performance at high temperatures. Summary of the Invention

[0004] The purpose of this invention is to provide a perovskite-type high-entropy ceramic material, its preparation method, and its application.

[0005] The technical solution adopted in this invention is: A method for preparing a perovskite-type high-entropy ceramic material includes the following steps: 1) The oxide powders at sites A and B are mixed and wet ball-milled. The oxide powders at site A are La2O3 powder, CeO2 powder, Nd2O3 powder, Sm2O3 powder, Er2O3 powder, and Pr6O. 11 The powder is prepared by drying and grinding at least 10 types of powders, including Eu2O3 powder, Gd2O3 powder, Dy2O3 powder, BaO powder, SrO powder, CaO powder, and MgO powder, and at least 6 types of B-site oxide powders, including Fe2O3 powder, CoO powder, NiO powder, Cr2O3 powder, MnO2 powder, TiO2 powder, CuO powder, and Al2O3 powder. 2) Add the mixed powder into a graphite crucible and press it firmly, then heat it with laser radiation to obtain perovskite-type high-entropy ceramic material.

[0006] Preferably, in step 1), the ratio of the total molar amount of metal atoms in the oxide powder at site A to the total molar amount of metal atoms in the oxide powder at site B is 1:1.

[0007] Preferably, the oxide powder at site A in step 1) comprises La2O3 powder, CeO2 powder, Nd2O3 powder, Sm2O3 powder, Er2O3 powder, and Pr6O. 11 The powder consists of at least 10 of the following: Eu2O3 powder, Gd2O3 powder, Dy2O3 powder, BaO powder, SrO powder, CaO powder, and MgO powder, in an equimolar ratio of metal atoms.

[0008] Preferably, the B-site oxide powder in step 1) is composed of at least six of the following powders in an equimolar ratio of metal atoms: Fe2O3 powder, CoO powder, NiO powder, Cr2O3 powder, MnO2 powder, TiO2 powder, CuO powder, and Al2O3 powder.

[0009] Preferably, the La2O3 powder, CeO2 powder, Nd2O3 powder, Sm2O3 powder, Er2O3 powder, and Pr6O powder mentioned in step 1) 11The particle sizes of the powders, including Eu2O3 powder, Gd2O3 powder, Dy2O3 powder, BaO powder, SrO powder, CaO powder, MgO powder, Fe2O3 powder, CoO powder, NiO powder, Cr2O3 powder, MnO2 powder, TiO2 powder, CuO powder, and Al2O3 powder, are all 1μm to 3μm, and the purity is ≥99.5%.

[0010] Preferably, the process parameters for wet ball milling in step 1) include: the ball milling medium is anhydrous ethanol, the ball milling equipment is a planetary ball mill, the weight ratio of powder raw material, ZrO2 balls and anhydrous ethanol is 1:4.0~5.0:1.5~2.5, the ball mill speed is 400r / min~800r / min, and the ball milling time is 20h~24h.

[0011] Preferably, the drying in step 1) is carried out at a temperature of 70℃ to 90℃ for a drying time of 0.5h to 1h.

[0012] Preferably, the inner cavity of the graphite crucible in step 2) is cylindrical, with an inner diameter of 10mm to 16mm and a depth of 3mm to 6mm.

[0013] Preferably, the process parameters for laser radiation heating in step 2) include: laser power of 900W to 1000W, laser duty cycle of 80% to 100%, laser spot diameter of 6mm to 8mm, heating temperature of 2600℃ to 3000℃, and heating time of 6s to 15s.

[0014] A perovskite-type high-entropy ceramic material is prepared by the above-described method.

[0015] An aerospace vehicle has a surface covered with a microwave absorbing coating, the microwave absorbing coating comprising the aforementioned perovskite-type high-entropy ceramic material.

[0016] The beneficial effects of this invention are: the perovskite-type high-entropy ceramic material of this invention has multi-band absorption characteristics, high service temperature, and stable performance at high temperatures, making it suitable for use in stealth coatings for aerospace vehicles. Furthermore, its preparation method is simple, the reaction time is short, and the production cost is low, making it suitable for large-scale industrial production and application.

[0017] Specifically: 1) The perovskite-type high-entropy ceramic material of this invention exhibits a super-large lattice distortion induced by the extreme mixing of A-site atoms and B-site atoms, which endows the high-entropy ceramic material with strong polarization loss capability. The effective absorption bandwidth of the high-entropy ceramic material at room temperature can reach 7.12 GHz (the effective absorption bandwidth is higher than that of the high-entropy perovskite (Y) reported in the literature). 0.2 La 0.2 Sm 0.2 Nd 0.2Gd 0.2 (CoO3 content increased by approximately 117%), possessing multi-band absorption characteristics (i.e., X-band and Ku-band), resulting in good electromagnetic stealth performance; 2) The perovskite-type high-entropy ceramic material of the present invention can withstand high temperatures of 600℃ (the service temperature is higher than that of high-entropy perovskites (γ-ray diopside) reported in the literature). 0.2 La 0.2 Sm 0.2 Nd 0.2 Gd 0.2 Even at 300℃, CoO3 still exhibits excellent multi-band electromagnetic absorption performance, with an effective absorption bandwidth reaching 7.04 GHz (the effective absorption bandwidth is higher than that of high-entropy perovskites (Y) reported in the literature). 0.2 La 0.2 Sm 0.2 Nd 0.2 Gd 0.2 (CoO3 increased by approximately 355%), exhibiting extremely strong stability in electromagnetic absorption performance; 3) The preparation method of the perovskite-type high-entropy ceramic material of the present invention is simple, the reaction time is short (the high-power laser radiation heating time is only 6s to 15s), the composition synthesis space is huge (extremely mixed 18-element high-entropy perovskite ceramics can be synthesized), and the production cost is low, making it suitable for large-scale industrial production and application. Attached Figure Description

[0018] Figure 1 The image shows the XRD pattern of the perovskite-type high-entropy ceramic material in Example 1.

[0019] Figure 2 The image shows the reflection loss of the perovskite-type high-entropy ceramic material in Example 1 at room temperature.

[0020] Figure 3 The diagram shows the reflection loss of the perovskite-type high-entropy ceramic material in Example 1 at 600°C.

[0021] Figure 4 The image shows the XRD pattern of the perovskite-type high-entropy ceramic material in Example 2.

[0022] Figure 5 The image shows the reflection loss of the perovskite-type high-entropy ceramic material in Example 2 at room temperature.

[0023] Figure 6 The image shows the XRD pattern of the perovskite-type high-entropy ceramic material in Example 3.

[0024] Figure 7 The image shows the reflection loss of the perovskite-type high-entropy ceramic material in Example 3 at room temperature.

[0025] Figure 8The images show the XRD patterns of the perovskite-type high-entropy ceramic materials of Comparative Example 1 and Comparative Example 2.

[0026] Figure 9 The diagram shows the reflection loss of the perovskite-type high-entropy ceramic material in Comparative Example 1 at room temperature.

[0027] Figure 10 The diagram shows the reflection loss of the perovskite-type high-entropy ceramic material in Comparative Example 2 at room temperature. Detailed Implementation

[0028] The present invention will be further explained and described below with reference to specific embodiments.

[0029] The La2O3 powder, CeO2 powder, Nd2O3 powder, Sm2O3 powder, Er2O3 powder, and Pr6O powder in Examples 1-3 and Comparative Examples 1-2 11 The particle sizes of the powders, including Eu2O3 powder, Gd2O3 powder, Dy2O3 powder, BaO powder, SrO powder, CaO powder, MgO powder, Fe2O3 powder, CoO powder, NiO powder, Cr2O3 powder, MnO2 powder, TiO2 powder, CuO powder, and Al2O3 powder, are all 1μm to 3μm, and the purity is ≥99.5%.

[0030] Example 1: A perovskite-type high-entropy ceramic material is prepared by the following method: 1) Mix 0.660g of BaO powder, 0.241g of CaO powder, 0.446g of SrO powder, 0.701g of La2O3 powder, 0.724g of Nd2O3 powder, 0.750g of Sm2O3 powder, and 0.732g of Pr6O... 11 0.757g of Eu2O3 powder, 0.823g of Er2O3 powder, 0.780g of Gd2O3 powder, 0.573g of Fe2O3 powder, 0.538g of CoO powder, 0.536g of NiO powder, 0.545g of Cr2O3 powder, 0.623g of MnO2 powder, and 0.573g of TiO2 powder were added to a ball mill jar, followed by anhydrous ethanol and ZrO2 balls. The weight ratio of the powder raw materials, ZrO2 balls, and anhydrous ethanol was 1:4:1.5. The ball mill jar was then placed in a planetary ball mill for ball milling at a speed of 500 r / min for 24 h. The slurry obtained from ball milling was then transferred to a rotary evaporator and rotary evaporated at 90°C for 1 h. After grinding and passing through a 200-mesh sieve, a mixed powder was obtained. 2) The mixed powder is added to a graphite crucible and compacted. The inner cavity of the graphite crucible is cylindrical with an inner diameter of 10 mm and a depth of 3 mm. The graphite crucible is then fixed to the laser heating stage in the vacuum chamber using a clamp for laser radiation heating. The laser radiation heating process parameters are as follows: laser power of 1000 W, laser duty cycle of 100%, laser spot diameter of 6 mm, heating temperature of 3000℃, heating time of 10 s, and natural cooling to room temperature to obtain perovskite-type high-entropy ceramic material (denoted as Sample-1; two-site high-entropy hexadecimal perovskite, with the chemical formula of its constituent components as: (Ba 0.1 Ca 0.1 Sr 0.1 La 0.1 Nd 0. 1Sm 0.1 Pr 0.1 Eu 0.1 Er 0.1 Gd 0.1 (Fe) 1 / 6 Co 1 / 6 Ni 1 / 6 Cr 1 / 6 Mn 1 / 6 Ti 1 / 6 O3).

[0031] Performance testing: 1) The X-ray diffraction (XRD) pattern of the perovskite-type high-entropy ceramic material (Sample-1) in this embodiment is shown below. Figure 1 As shown.

[0032] Depend on Figure 1 It can be seen that Sample-1 is a single-phase solid solution, and no other impurity phases were found.

[0033] 2) The perovskite-type high-entropy ceramic material (Sample-1) of this embodiment was sintered into a bulk material in a spark plasma sintering apparatus at a sintering temperature of 1600℃ and a holding time of 30 min. The bulk material was then processed into Sample 1 (22.86 mm long, 10.16 mm wide, and 2 mm–3 mm thick) and Sample 2 (15.799 mm long, 7.899 mm wide, and 2 mm–3 mm thick). The absorption performance was then tested using a network vector analyzer (Sample 1 was used to measure absorption performance in the frequency range of 8.2 GHz–12.4 GHz, and Sample 2 was used to measure absorption performance in the frequency range of 12.4 GHz–18 GHz). The resulting reflection loss diagram at room temperature is shown below. Figure 2 As shown, the reflection loss diagram at 600℃ is as follows. Figure 3 As shown.

[0034] Depend on Figure 2It can be seen that the sample made in Sample-1 has an effective absorption bandwidth of 7.12 GHz, a reflection loss of -48.1 dB, and a thickness of 1.9 mm at room temperature, exhibiting excellent electromagnetic wave absorption performance. The reason is that the extreme mixing of A-site atoms and B-site atoms induces ultra-large lattice distortion, resulting in high vacancy defect concentration and strong local element fluctuations, thereby increasing conductivity loss and polarization loss.

[0035] Depend on Figure 3 It can be seen that the sample made in Sample-1 has an effective absorption bandwidth of 7.04 GHz, a reflection loss of -47.1 dB, and a thickness of 1.2 mm at 600 °C, and has excellent electromagnetic wave absorption performance. The reason is that due to the entropy-driven stabilization effect, high concentration of vacancy defects and strong local element fluctuations can still exist stably at high temperatures.

[0036] Example 2: A perovskite-type high-entropy ceramic material is prepared by the following method: 1) Mix 0.658g of BaO powder, 0.241g of CaO powder, 0.445g of SrO powder, 0.699g of La2O3 powder, 0.722g of Nd2O3 powder, 0.749g of Sm2O3 powder, and 0.731g of Pr6O... 11 0.755g of Eu2O3 powder, 0.821g of Er2O3 powder, 0.801g of Dy2O3 powder, 0.571g of Fe2O3 powder, 0.536g of CoO powder, 0.534g of NiO powder, 0.544g of Cr2O3 powder, 0.622g of MnO2 powder, and 0.571g of TiO2 powder were added to a ball mill jar, followed by anhydrous ethanol and ZrO2 balls. The weight ratio of the powder raw materials, ZrO2 balls, and anhydrous ethanol was 1:4:1.5. The ball mill jar was then placed in a planetary ball mill for ball milling at a speed of 500 r / min for 24 h. The slurry obtained from ball milling was then transferred to a rotary evaporator and rotary evaporated at 90°C for 1 h. After grinding and passing through a 200-mesh sieve, a mixed powder was obtained. 2) The mixed powder is added to a graphite crucible and compacted. The inner cavity of the graphite crucible is cylindrical, with an inner diameter of 10 mm and a depth of 3 mm. The graphite crucible is then fixed to the laser heating stage in the vacuum chamber using a clamp for laser radiation heating. The laser radiation heating process parameters are as follows: laser power of 1000 W, laser duty cycle of 100%, laser spot diameter of 6 mm, heating temperature of 3000℃, heating time of 10 s, and natural cooling to room temperature to obtain perovskite-type high-entropy ceramic material (denoted as Sample-2; two-site high-entropy hexadecimal perovskite, with the chemical formula of its constituent components as: (Ba 0.1 Ca0.1 Sr 0.1 La 0.1 Nd 0. 1Sm 0.1 Pr 0.1 Eu 0.1 Er 0.1 Dy 0.1 (Fe) 1 / 6 Co 1 / 6 Ni 1 / 6 Cr 1 / 6 Mn 1 / 6 Ti 1 / 6 O3).

[0037] Performance testing: 1) The XRD pattern of the perovskite-type high-entropy ceramic material (Sample-2) in this embodiment is shown below. Figure 4 As shown.

[0038] Depend on Figure 4 It can be seen that Sample-2 is a single-phase solid solution, and no other impurity phases were found.

[0039] 2) The reflection loss diagram of the perovskite-type high-entropy ceramic material (Sample-2) in this embodiment at room temperature is shown in the figure below. Figure 5 As shown (the test method is the same as in Example 1).

[0040] Depend on Figure 5 It can be seen that the sample made in Sample-2 has an effective absorption bandwidth of 6.96 GHz, a reflection loss of -40.1 dB, and a thickness of 2.1 mm at room temperature, exhibiting excellent electromagnetic wave absorption performance. This is because the extreme mixing of A-site atoms and B-site atoms induces ultra-large lattice distortion, resulting in high vacancy defect concentration and strong local element fluctuations, thereby increasing conductivity loss and polarization loss.

[0041] Example 3: A perovskite-type high-entropy ceramic material is prepared by the following method: 1) Mix 0.604g of BaO powder, 0.221g of CaO powder, 0.408g of SrO powder, 0.642g of La2O3 powder, 0.663g of Nd2O3 powder, 0.687g of Sm2O3 powder, and 0.671g of Pr6O powder. 11Powder, 0.694g Eu2O3 powder, 0.754g Er2O3 powder, 0.735g Dy2O3 powder, 0.678g CeO2 powder, 0.495g Fe2O3 powder, 0.464g CoO powder, 0.463g NiO powder, 0.471g Cr2O3 powder, 0.539g MnO2 powder, 0.495g TiO2 powder, and 0.316 g of Al2O3 powder was added to a ball mill jar, followed by anhydrous ethanol and ZrO2 balls. The weight ratio of the powder, ZrO2 balls and anhydrous ethanol was 1:4:1.5. The ball mill jar was then placed in a planetary ball mill for ball milling. The ball mill speed was controlled at 500 r / min and the ball milling time was 24 h. The slurry obtained from ball milling was then transferred to a rotary evaporator and rotary evaporated at 90°C for 1 h. After grinding and passing through a 200-mesh sieve, a mixed powder was obtained. 2) The mixed powder is added to a graphite crucible and compacted. The inner cavity of the graphite crucible is cylindrical, with an inner diameter of 10 mm and a depth of 3 mm. The graphite crucible is then fixed to the laser heating stage in the vacuum chamber using a clamp for laser radiation heating. The laser radiation heating process parameters are as follows: laser power of 1000 W, laser duty cycle of 100%, laser spot diameter of 6 mm, heating temperature of 3000℃, heating time of 10 s, and natural cooling to room temperature to obtain perovskite-type high-entropy ceramic material (denoted as Sample-3; two-site high-entropy 18-membered perovskite, with the chemical formula of its constituent components as: (Ba 1 / 11 Ca 1 / 11 Sr 1 / 11 La 1 / 11 Nd 1 / 11 Sm 1 / 11 Pr 1 / 11 Eu 1 / 11 Er 1 / 11 Dy 1 / 11 Ce 1 / 11 (Fe) 1 / 7 Co 1 / 7 Ni 1 / 7 Cr 1 / 7 Mn 1 / 7 Ti 1 / 7 Al 1 / 7 O3).

[0042] Performance testing: 1) The XRD pattern of the perovskite-type high-entropy ceramic material (Sample-3) in this embodiment is shown below. Figure 6 As shown.

[0043] Depend on Figure 6 It can be seen that Sample-3 is a single-phase solid solution, and no other impurity phases were found.

[0044] 2) The reflection loss diagram of the perovskite-type high-entropy ceramic material (Sample-3) in this embodiment at room temperature is shown in the figure below. Figure 7 As shown (the test method is the same as in Example 1).

[0045] Depend on Figure 7 It can be seen that the sample made in Sample-3 has an effective absorption bandwidth of 7.52 GHz, a reflection loss of -51.8 dB, and a thickness of 3.1 mm at room temperature, exhibiting excellent electromagnetic wave absorption performance. The reason is that the extreme mixing of A-site atoms and B-site atoms induces ultra-large lattice distortion, resulting in high vacancy defect concentration and strong local element fluctuations, thereby increasing conductivity loss and polarization loss.

[0046] Comparative Example 1: A perovskite-type high-entropy ceramic material is prepared by the following method: 1) Mix 0.567g of BaO powder, 0.207g of CaO powder, 0.383g of SrO powder, 0.149g of MgO powder, 0.603g of La2O3 powder, 0.622g of Nd2O3 powder, 0.645g of Sm2O3 powder, and 0.630g of Pr6O powder. 11 0.651g of Eu2O3 powder, 0.637g of CeO2 powder, 0.671g of Gd2O3 powder, 0.690g of Dy2O3 powder, and 3.545g of Fe2O3 powder were added to a ball mill jar, followed by anhydrous ethanol and ZrO2 balls. The weight ratio of the powder raw materials, ZrO2 balls, and anhydrous ethanol was 1:4:1.5. The ball mill jar was then placed in a planetary ball mill for ball milling at a speed of 500 r / min for 24 h. The slurry obtained from ball milling was then transferred to a rotary evaporator and rotary evaporated at 90°C for 1 h. After grinding and passing through a 200-mesh sieve, a mixed powder was obtained. 2) The mixed powder was added to a graphite crucible and compacted. The inner cavity of the graphite crucible was cylindrical, with an inner diameter of 10 mm and a depth of 3 mm. The graphite crucible was then fixed to the laser heating stage in the vacuum chamber using a clamp for laser radiation heating. The laser radiation heating process parameters were as follows: laser power of 1000 W, laser duty cycle of 100%, laser spot diameter of 6 mm, heating temperature of 3000℃, heating time of 10 s, and natural cooling to room temperature to obtain perovskite-type high-entropy ceramic material (denoted as Sample-4; A-site high-entropy twelve-membered perovskite, with the chemical formula of its constituent components as: (Ba 1 / 12 Ca 1 / 12 Sr 1 / 12 Mg 1 / 12 La 1 / 12 Nd 1 / 12 Sm 1 / 12Pr 1 / 12 Eu 1 / 12 Ce 1 / 12 Gd 1 / 12 Dy 1 / 12 (FeO3).

[0047] Performance testing: 1) The XRD pattern of the perovskite-type high-entropy ceramic material (Sample-4) in this comparative example is shown below. Figure 8 As shown.

[0048] Depend on Figure 8 It can be seen that Sample-4 is a single-phase solid solution, and no other impurity phases were found.

[0049] 2) The reflection loss diagram of the perovskite-type high-entropy ceramic material (Sample-4) in this comparative example at room temperature is shown in the figure below. Figure 9 As shown (the test method is the same as in Example 1).

[0050] Depend on Figure 9 It can be seen that the sample made in Sample-4 has an effective absorption bandwidth of 6.56 GHz at room temperature, a reflection loss of -42.1 dB, and a thickness of 3.1 mm. Its electromagnetic wave absorption performance is significantly worse than that of the perovskite-type high-entropy ceramic material in Example 1. The reason is that the high-entropy perovskite ceramic has fewer metal elements incorporated, and the small lattice distortion produces a low vacancy defect concentration and weak local element fluctuations, which reduces conductivity loss and polarization loss.

[0051] Comparative Example 2: A perovskite-type high-entropy ceramic material is prepared by the following method: 1) Add 6.837g of La2O3 powder, 0.419g of Fe2O3 powder, 0.393g of CoO powder, 0.392g of NiO powder, 0.399g of Cr2O3 powder, 0.456g of MnO2 powder, 0.417g of CuO powder, 0.267g of Al2O3 powder, and 0.419g of TiO2 powder to a ball mill jar, then add anhydrous ethanol and ZrO2 balls. The weight ratio of the powder raw materials, ZrO2 balls, and anhydrous ethanol is 1:4:1.5. Then, put the ball mill jar into a planetary ball mill for ball milling. Control the ball mill speed at 500r / min and the ball milling time at 24h. Then transfer the slurry obtained from ball milling to a rotary evaporator and rotary evaporate at 90℃ for 1h. Then grind and pass through a 200-mesh sieve to obtain a mixed powder. 2) The mixed powder was added to a graphite crucible and compacted. The inner cavity of the graphite crucible was cylindrical, with an inner diameter of 10 mm and a depth of 3 mm. The graphite crucible was then fixed to the laser heating stage in the vacuum chamber using a clamp for laser radiation heating. The laser radiation heating process parameters were as follows: laser power of 1000 W, laser duty cycle of 100%, laser spot diameter of 6 mm, heating temperature of 3000℃, heating time of 10 s, and natural cooling to room temperature to obtain perovskite-type high-entropy ceramic material (denoted as Sample-5; B-site high-entropy octagonal perovskite, with the chemical formula of La(Fe)). 1 / 8 Co 1 / 8 Ni 1 / 8 Cr 1 / 8 Mn 1 / 8Cu 1 / 8 Al 1 / 8 Ti 1 / 8 O3).

[0052] Performance testing: 1) The XRD pattern of the perovskite-type high-entropy ceramic material (Sample-5) in this comparative example is shown below. Figure 8 As shown.

[0053] Depend on Figure 8 It can be seen that Sample-5 is a single-phase solid solution, and no other impurity phases were found.

[0054] 2) The reflection loss diagram of the perovskite-type high-entropy ceramic material (Sample-5) in this comparative example at room temperature is shown in the figure below. Figure 10 As shown (the test method is the same as in Example 1).

[0055] Depend on Figure 10 It can be seen that the sample made in Sample-5 has an effective absorption bandwidth of 6.16 GHz at room temperature, a reflection loss of -34.0 dB, and a thickness of 3.0 mm. Its electromagnetic wave absorption performance is significantly worse than that of the perovskite-type high-entropy ceramic material in Example 1. The reason is that the high-entropy perovskite ceramic is doped with metals with small differences in ionic radius. The small lattice distortion produces a low vacancy defect concentration and weak local element fluctuations, which reduces conductivity loss and polarization loss.

[0056] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a perovskite-type high-entropy ceramic material, characterized in that, Includes the following steps: 1) The oxide powders at sites A and B are mixed and wet ball-milled. The oxide powders at site A are La2O3 powder, CeO2 powder, Nd2O3 powder, Sm2O3 powder, Er2O3 powder, and Pr6O. 11 The powder is prepared by drying and grinding at least 10 types of powders, including Eu2O3 powder, Gd2O3 powder, Dy2O3 powder, BaO powder, SrO powder, CaO powder, and MgO powder, and at least 6 types of B-site oxide powders, including Fe2O3 powder, CoO powder, NiO powder, Cr2O3 powder, MnO2 powder, TiO2 powder, CuO powder, and Al2O3 powder. 2) Add the mixed powder into a graphite crucible and press it firmly, then heat it with laser radiation to obtain perovskite-type high-entropy ceramic material.

2. The preparation method according to claim 1, characterized in that: Step 1) The ratio of the total molar amount of metal atoms in the oxide powder at site A to the total molar amount of metal atoms in the oxide powder at site B is 1:

1.

3. The preparation method according to claim 1 or 2, characterized in that: Step 1) The oxide powder at site A consists of La2O3 powder, CeO2 powder, Nd2O3 powder, Sm2O3 powder, Er2O3 powder, and Pr6O. 11 The powder consists of at least 10 types of powders, including Eu2O3 powder, Gd2O3 powder, Dy2O3 powder, BaO powder, SrO powder, CaO powder, and MgO powder, in an equimolar ratio of metal atoms; the B-site oxide powder in step 1) consists of at least 6 types of powders, including Fe2O3 powder, CoO powder, NiO powder, Cr2O3 powder, MnO2 powder, TiO2 powder, CuO powder, and Al2O3 powder, in an equimolar ratio of metal atoms.

4. The preparation method according to claim 1 or 2, characterized in that: Step 1) The La2O3 powder, CeO2 powder, Nd2O3 powder, Sm2O3 powder, Er2O3 powder, and Pr6O powder are mentioned. 11 The particle sizes of the powders, including Eu2O3 powder, Gd2O3 powder, Dy2O3 powder, BaO powder, SrO powder, CaO powder, MgO powder, Fe2O3 powder, CoO powder, NiO powder, Cr2O3 powder, MnO2 powder, TiO2 powder, CuO powder, and Al2O3 powder, are all 1μm to 3μm, and the purity is ≥99.5%.

5. The preparation method according to claim 1 or 2, characterized in that: The process parameters for wet ball milling in step 1) include: the ball milling medium is anhydrous ethanol, the ball milling equipment is a planetary ball mill, the weight ratio of powder raw material, ZrO2 balls and anhydrous ethanol is 1:4.0~5.0:1.5~2.5, the ball mill speed is 400r / min~800r / min, and the ball milling time is 20h~24h.

6. The preparation method according to claim 1 or 2, characterized in that: Step 1) The drying is carried out at a temperature of 70℃~90℃ for a drying time of 0.5h~1h.

7. The preparation method according to claim 1, characterized in that: Step 2) The inner cavity of the graphite crucible is cylindrical, with an inner diameter of 10mm to 16mm and a depth of 3mm to 6mm.

8. The preparation method according to claim 1 or 7, characterized in that: Step 2) The process parameters for laser radiation heating include: laser power of 900W to 1000W, laser duty cycle of 80% to 100%, laser spot diameter of 6mm to 8mm, heating temperature of 2600℃ to 3000℃, and heating time of 6s to 15s.

9. A perovskite-type high-entropy ceramic material, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 8.

10. An aerospace vehicle, characterized in that, The surface is covered with a microwave absorbing coating; the microwave absorbing coating comprises the perovskite-type high-entropy ceramic material as described in claim 9.

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