Spinel-perovskite three-phase high-entropy ceramic powder material

Abstract

The application relates to a spinel-perovskite three-phase high-entropy ceramic powder material, which has a chemical formula of (A 1x A 2y A 3z A 4u A 5v )Mn2O4, wherein A1, A2, A3, A4 and A5 are four transition metal elements in Ca, Cu, Ni, Co, Zn and Mg and one rare earth element in La and Pr, the molar ratio of metal atoms is x:y:z:u:v:2, and x+y+z+u+v=1; the high-entropy ceramic powder material has two cubic crystal system spinel phases and a perovskite phase. The three phases of the high-entropy ceramic powder material coexist, have excellent wide-band emissivity and high-temperature thermal stability, and can be widely used as an infrared radiation material in high-temperature infrared radiation environments, such as aerospace thermal protection, industrial high-temperature kiln, power station boiler thermal management systems and the like.

Description

Technical Field

[0001] This invention relates to the field of infrared radiation heating / heat dissipation materials, and more particularly to a spinel-perovskite three-phase high-entropy ceramic powder material. Background Technology

[0002] Against the backdrop of the global energy crisis and the increasingly urgent need for energy conservation in high-temperature industries, infrared radiation thermal management materials are playing a crucial role in radiation cooling, high-temperature resistant linings for industrial furnaces and kilns, aerospace thermal protection, and heat dissipation for electronic devices. Especially in extreme environments where high temperatures, strong thermal shock, and corrosive media coexist, materials must maintain high emissivity across a wide spectral range (0.78–16 μm) and possess excellent thermal stability and mechanical properties. Traditional metal oxides and ceramic emitters, such as chromite and iron-manganese-based oxides, while possessing certain high-temperature resistance characteristics, generally suffer from low emissivity, narrow spectral response ranges, and poor high-temperature phase stability, making it difficult to meet the performance requirements of next-generation high-load thermal equipment.

[0003] In recent years, high-entropy oxides, as a novel multi-principal element material system, have attracted widespread attention in the field of high-temperature functional materials due to their unique thermodynamic stability, lattice distortion effect, and flexibly modulated electronic structure brought about by high configurational entropy. Currently, some single-phase high-entropy oxides have achieved emissivity exceeding 0.86 in the 2.5–16 μm band, exhibiting superior infrared performance compared to traditional ceramics. However, existing research has largely focused on single-phase high-entropy systems, failing to fully utilize the synergistic enhancement potential of multiphase coherent interfaces, lattice strain, and defect engineering on optoelectronic properties. Multiphase coexisting high-entropy ceramic systems can achieve phase equilibrium through entropy stabilization effects, maintaining high-temperature stability while further broadening the infrared emission band and improving emissivity levels through phonon scattering, polarization enhancement, and bandgap modulation induced by heterogeneous interfaces. In 2022, G. Dai et al. successfully prepared (Fe) high-entropy oxides by solid-state sintering under a hydrogen atmosphere. 0.2x Co 0.2 Ni 0.2 , Cr 0.2 , Mn 0.23O4 (x=1~5) two-phase high-entropy materials, in which spinel and alloy phases coexist, significantly enhance the microwave absorption performance of the material (Adv. Funct. Mater. 2022,32, 2205325). For high-entropy three-phase materials, the spinel phase exhibits good high-temperature stability and high mid- and far-infrared emissivity, while the perovskite phase, due to its strong lattice asymmetry and rich phonon modes, displays excellent thermal radiation characteristics in the infrared band (2.5~16μm). By designing the microscopic composite of these two phases through high-entropy, not only can the emission band be synergistically broadened, but the entropy driving force can also be used to suppress high-temperature phase separation, improving the reliability of the material in extreme environments. Nevertheless, research on the application of spinel / perovskite three-phase high-entropy ceramics constructed using solid-state methods for infrared radiation remains lacking. Therefore, developing a high-entropy ceramic material with a spinel-perovskite coexisting structure and studying its controllable preparation method and infrared radiation performance is of significant scientific and engineering value for promoting the application of high-entropy materials in the field of high-temperature thermal management. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a high-performance spinel-perovskite three-phase high-entropy ceramic powder material.

[0005] To address the aforementioned problems, the present invention provides a spinel-perovskite three-phase high-entropy ceramic powder material, characterized in that: the chemical formula of the three-phase high-entropy ceramic powder material is (A... 1x A 2y A 3z A 4u A 5v Mn2O4, wherein A1, A2, A3, A4, and A5 are four transition metal elements from Ca, Cu, Ni, Co, Zn, and Mg, and one rare earth element from La and Pr, with a metal atom molar ratio of x:y:z:u:v:2, and x+y+z+u+v=1; it has two cubic crystal systems: spinel phase and perovskite phase.

[0006] The solar emissivity of the three-phase high-entropy ceramic powder material is ≥89% in the range of 0.3 ~ 2.5μm, and the infrared emissivity is ≥90% in the range of 2.5 ~ 16μm.

[0007] The preparation method of the spinel-perovskite three-phase high-entropy ceramic powder material as described above is characterized in that: the method refers to using any four of the following powders: CaO, CuO, NiO, CoO, ZnO, and MgO, as well as La2O3 and Pr5O. 11Using any one of the powders and MnO2 as raw materials, ball milling is performed according to the metal atomic molar ratio x:y:z:u:v:2, where x+y+z+u+v=1. After drying and grinding, the mixture powder is obtained. The mixture powder is then calcined at high temperature in a muffle furnace under air atmosphere and cooled to room temperature to obtain a three-phase high-entropy ceramic powder material with two spinel structures and one perovskite structure.

[0008] The conditions for ball milling refer to using a planetary ball mill, using ultrapure water as the ball milling solvent, a ball milling speed of 300~500 r / min, a ball milling time of 5~10 hours, and a ball-to-water mass ratio of 2~5:1:3.

[0009] The drying conditions refer to a temperature of 80~100℃ and a drying time of 12~24 hours.

[0010] The conditions for high-temperature calcination are a calcination temperature of 900~1300℃, a heating rate of 3~5℃ / min, and a calcination time of 4~8 hours.

[0011] The cooling method is one of furnace cooling, air quenching cooling, and liquid nitrogen quenching cooling.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] 1. The high-entropy ceramic material of the present invention has three crystal structures: cubic spinel structure, tetragonal spinel structure, and orthorhombic perovskite structure. In the spinel structure, A ions are coordinated with 4 oxygen ions and located in tetrahedral voids, and B ions are coordinated with 6 oxygen atoms and located in octahedral voids. In the perovskite phase, A-site rare earth ions form a 12-coordinate structure and are located in the interstices formed by octahedra. The B-site is a transition metal element, and the transition metal ion is coordinated with six oxygen ions to form an octahedral structure.

[0014] 2. Compared with traditional single-phase materials, the high-entropy ceramic material described in this invention introduces multivalent metals, resulting in abundant local defects. The defect centers regulate the electron density distribution through charge transfer and orbital hybridization. Furthermore, this electronic structure engineering effectively narrows the material's bandgap and promotes oxygen vacancy formation, effectively enhancing the material's infrared absorption capability and free carrier density, thereby strengthening the material's response to short-wave infrared (0.3~2.5μm).

[0015] 3. Due to the controllable coexistence of the three phases, the present invention significantly improves the infrared emission performance of the material, accompanied by obvious interface mismatch, rich defect network and atomic level local strain field. Its excellent infrared radiation performance is characterized by an emissivity of ≥89% in the 0.3 ~ 2.5 μm band and an emissivity of ≥90% in the 2.5 ~ 16 μm atmospheric window region.

[0016] 4. The high-entropy ceramic material described in this invention exhibits an emissivity of over 0.9 in the near-infrared band (2.5~16 μm). This is due to the significant interfacial strain induced by lattice mismatch and thermal expansion differences between the multiphase structures, which further excites phonon modes within the crystal. Furthermore, the rich defect network generated by the interfacial mismatch in the multiphase structure enhances the coupling between lattice vibrations and mid-to-long-wave infrared radiation.

[0017] 5. The high-entropy ceramic material of this invention features a coexistence of spinel / perovskite three phases. The perovskite phase, through its asymmetric lattice structure, effectively enhances the excitation of lattice vibration modes in the mid-infrared to far-infrared band, thereby strengthening the material's phonon absorption capacity in this band. Simultaneously, the spinel phase exhibits high structural and thermodynamic stability, maintaining lattice integrity and morphological stability in high-temperature environments and resisting thermal stress shocks. The synergistic effect of these two structures achieves an organic unity between infrared response performance and high-temperature structural stability (1100 ℃), significantly improving the material's overall reliability under extreme service environments.

[0018] 6. This invention employs mechanical wet grinding and solid-phase synthesis calcination, which can achieve highly uniform mixing of multiple metal elements. The calcination process is controllable, has good repeatability, and allows for flexible parameter adjustment. It has advantages such as simple operation, short production cycle, and industrial production capability. The material can be widely used in high-temperature infrared radiation environments, such as aerospace thermal protection, industrial high-temperature kilns, and power plant boiler thermal management systems. Attached Figure Description

[0019] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0020] Figure 1 This is the XRD pattern of (La, Ca, Cu, Ni, Mg)Mn2O4 in Example 1 of the present invention.

[0021] Figure 2 The infrared radiation spectrum of (La, Ca, Cu, Ni, Mg)Mn2O4 in the 0.3~2.5 μm band is shown in Example 1 of the present invention.

[0022] Figure 3 The infrared radiation spectrum of (La, Ca, Cu, Ni, Mg)Mn2O4 in the 2.5~16 μm band is shown in Example 1 of the present invention. Detailed Implementation

[0023] A spinel-perovskite three-phase high-entropy ceramic powder material, the chemical formula of which is (A) 1x A 2y A 3z A 4u A 5vMn₂O₄, wherein A₁, A₂, A₃, A₄, and A₅ are four transition metal elements from Ca, Cu, Ni, Co, Zn, and Mg, and one rare earth element from La and Pr, with a metal atom molar ratio of x:y:z:u:v:2, and x+y+z+u+v=1; it has two cubic crystal systems: a spinel phase and a perovskite phase. This three-phase high-entropy ceramic powder material exhibits a solar emissivity ≥89% in the range of 0.3~2.5μm and an infrared emissivity ≥90% in the range of 2.5~16μm.

[0024] Its preparation method refers to using any four of the following powders: CaO, CuO, NiO, CoO, ZnO, and MgO, as well as La2O3 and Pr5O. 11 Using any one of the powders and MnO2 as raw materials, the mixture is ball-milled in a planetary ball mill according to the metal atomic molar ratio x:y:z:u:v:2, where x+y+z+u+v=1. Ultrapure water is used as the ball milling solvent. The ball milling speed is 300-500 r / min, and the milling time is 5-10 hours. The mass ratio of ball to material to water (g / g) is 2-5:1:3. After mixing, the mixture is dried at 80-100℃ for 12-24 hours to constant weight and then ground to obtain the mixed powder. The mixed powder is then calcined in a muffle furnace under air atmosphere at a temperature of 900-1300℃, a heating rate of 3-5℃ / min, and a calcination time of 4-8 hours. Finally, it is cooled to room temperature using one of the following methods: furnace cooling, air quenching, or liquid nitrogen quenching, to obtain a three-phase high-entropy ceramic powder material with two spinel structures and one perovskite structure.

[0025] Example 1

[0026] A method for preparing spinel-perovskite three-phase high-entropy ceramic powder material:

[0027] Powders of La₂O₃ (0.1 mol), CaO (0.2 mol), CuO (0.2 mol), NiO (0.2 mol), MgO (0.2 mol), and MnO₂ (2 mol) were weighed according to a metal atomic molar ratio of 0.2:0.2:0.2:0.2:2. These powders were then ball-milled using a planetary ball mill with ultrapure water as the milling solvent. The mass ratio of ball to powder (g / g) was 2:1:3. The milling was performed for 1 hour at 300 r / min, followed by a 10-min pause, constituting one milling cycle. This was repeated for another 1 hour at 300 r / min, for a total of 5 hours. The mixture was then dried at 80℃ for 12 hours and ground to obtain the final powder. The powder was then calcined in air in stages, with the temperature increased at 5℃ / min to 900℃ for 4 hours. After calcination, the material is cooled in the furnace and then ground to obtain a three-phase (La, Ca, Cu, Ni, Mg)Mn2O4 high-entropy ceramic powder material.

[0028] X-ray diffraction analysis was performed on the obtained (La, Ca, Cu, Ni, Mg)Mn2O4 high-entropy ceramic powder material, and the results are as follows: Figure 1 As shown, this spectral line is similar to the CuMn2O4 spectrum (PDF#34-1400) with a cubic spinel structure, the MgMn2O4 spectrum (PDF#23-0392) with a tetragonal spinel structure, and the La spectrum with a perovskite structure in the ICDD database. 0.6 Ca 0.4 The crystal forms of the MnO3 spectral lines (PDF#46-0513) are very similar, indicating that the high-entropy ceramic powder material prepared in this embodiment has a coexistence of spinel and perovskite structures, and the three phases coexist.

[0029] The emissivity of the material was evaluated using a Lambda 950 UV / Vis / NIR spectrophotometer (equipped with a 150mm integrating sphere) manufactured by PerkinElmer, USA. The emissivity in the 0.3–2.5 μm wavelength range was measured, and then calculated according to the formula in the international standard ISO 9845-1 (1992). The infrared emissivity of the material was evaluated using a TSS-5X-2 infrared emissivity meter manufactured by Senor, Japan. The infrared emissivity in the 2.5–16 μm wavelength range was measured.

[0030] 0.2 g of (La, Ca, Cu, Ni, Mg)Mn₂O₄ high-entropy ceramic powder was taken, and its infrared emissivity in the 22.5–16 μm band was measured to be 0.90, and its emissivity in the 0.3–2.5 μm band was 0.89. Figures 2-3 As shown.

[0031] The prepared high-entropy ceramic powder was placed in an air atmosphere in a box furnace and subjected to a thermal stability test at 1100 °C for 12 hours. The results showed that the high-entropy ceramic powder exhibited a stable crystal structure after the thermal stability test, with an emissivity variation within the range of 0.01.

[0032] Example 2

[0033] A method for preparing spinel-perovskite three-phase high-entropy ceramic powder material:

[0034] Pr5O was weighed according to the metal atomic molar ratio of 0.2:0.2:0.2:0.2:0.2:2. 11 Powders of 0.04 mol CaO, 0.2 mol CuO, 0.2 mol NiO, 0.2 mol MgO, and 2 mol MnO2 were ball-milled using a planetary ball mill with ultrapure water as the milling solvent. The mass ratio of ball to powder (g / g) was 4:1:3. The milling was performed for 1 hour at 400 r / min, followed by a 10-min pause, constituting one milling cycle. This was repeated for another hour at 400 r / min, for a total of 5 hours. The mixture was then dried at 90℃ for 15 hours and ground to obtain the final powder. The powder was then calcined in air in stages, with the temperature increased at 4℃ / min to 1000℃ for 5 hours. After calcination, the powder was cooled in the furnace and ground to obtain a three-phase (Pr, Ca, Cu, Ni, Mg)Mn2O4 high-entropy ceramic powder material.

[0035] The infrared radiation properties and thermal stability of the obtained (Pr, Ca, Cu, Ni, Mg)Mn2O4 high-entropy ceramic powder material were studied: the test method and the amount of test sample were the same as in Example 1.

[0036] The results show that the emissivity of the high-entropy ceramic powder material is 0.90 in the 0.3~2.5 μm band and 0.91 in the infrared band of 2.5~16 μm. After the thermal stability experiment, the crystal structure is stable and the emissivity variation range is within 0.01.

[0037] Example 3

[0038] A method for preparing spinel-perovskite three-phase high-entropy ceramic powder material:

[0039] Powders of La₂O₃ (0.1 mol), CaO (0.2 mol), CuO (0.2 mol), NiO (0.2 mol), MgO (0.2 mol), and MnO₂ (2 mol) were weighed according to a metal atomic molar ratio of 0.2:0.2:0.2:0.2:2. These powders were then ball-milled using a planetary ball mill with ultrapure water as the milling solvent. The mass ratio of ball to powder (g / g) was 3:1:3. The milling was performed for 1 hour at 500 r / min, followed by a 10-min pause, constituting one milling cycle. This was repeated for another hour at 500 r / min, for a total of 8 hours. The mixture was then dried at 100℃ for 10 hours and ground to obtain the final powder. The powder was then calcined in air in stages, with the temperature increased at 3℃ / min to 1100℃ for 8 hours. After calcination, the material is cooled in the furnace and then ground to obtain a three-phase (La, Ca, Cu, Ni, Mg)Mn2O4 high-entropy ceramic powder material.

[0040] The infrared radiation properties and thermal stability of the obtained (La, Ca, Cu, Ni, Mg)Mn2O4 high-entropy ceramic powder material were studied: the test method and the amount of test sample were the same as in Example 1.

[0041] The results show that the emissivity of the high-entropy ceramic powder material is 0.91 in the 0.3~2.5 μm band and 0.915 in the 2.5~16 μm band; after the thermal stability experiment, the crystal structure is stable and the emissivity variation range is within 0.01.

[0042] Example 4

[0043] A method for preparing spinel-perovskite three-phase high-entropy ceramic powder material:

[0044] Powders of La₂O₃ (0.1 mol), CaO (0.2 mol), CuO (0.2 mol), NiO (0.2 mol), ZnO (0.2 mol), and MnO₂ (2 mol) were weighed according to a metal atomic molar ratio of 0.2:0.2:0.2:0.2:2. These powders were then ball-milled using a planetary ball mill with ultrapure water as the milling solvent. The mass ratio of ball to powder (g / g) was 2:1:3. The milling was performed for 1 hour at 400 r / min, followed by a 10-min pause, constituting one milling cycle. This was repeated for another hour at 500 r / min, for a total of 5 hours. The mixture was then dried at 80℃ for 10 hours and ground to obtain the final powder. The powder was then calcined in air in stages, with the temperature increased at 3℃ / min to 1000℃ for 8 hours. After calcination, the material is cooled in the furnace and then ground to obtain a three-phase (La, Ca, Cu, Ni, Zn)Mn2O4 high-entropy ceramic powder material.

[0045] The infrared radiation properties and thermal stability of the obtained (La, Ca, Cu, Ni, Zn)Mn2O4 high-entropy ceramic powder were studied: the test methods and sample amounts were the same as in Example 1.

[0046] The results show that the emissivity of the high-entropy ceramic powder material is 0.905 in the 0.3~2.5 μm band and 0.914 in the 2.5~16 μm band; after the thermal stability experiment, the crystal structure is stable and the emissivity variation range is within 0.01.

[0047] The above description only illustrates the preferred embodiments of the present invention and should not be construed as limiting the scope of the claims. The present invention is not limited to the above embodiments, and variations in its specific structure are permitted. All modifications made within the scope of the independent claims of this invention are also within the scope of protection of this invention.

Claims

1. A spinel-perovskite three-phase high-entropy ceramic powder material, characterized in that: The chemical formula of the three-phase high-entropy ceramic powder material is (A) 1x A 2y A 3z A 4u A 5v Mn₂O₄, wherein A₁, A₂, A₃, A₄, and A₅ are four transition metal elements (including Ca, Cu, Ni, Co, Zn, and Mg) and one rare earth element (La and Pr), with a metal atom molar ratio of x:y:z:u:v:2, and x+y+z+u+v=1; it has three crystal structures: cubic spinel structure, tetragonal spinel structure, and orthorhombic perovskite structure; the solar emissivity of the three-phase high-entropy ceramic powder material is ≥89% in the range of 0.3~2.5μm, and the infrared emissivity is ≥90% in the range of 2.5~16μm.

2. The preparation method of a spinel-perovskite three-phase high-entropy ceramic powder material as described in claim 1, characterized in that: This method refers to using any four of the following powders: CaO, CuO, NiO, CoO, ZnO, and MgO, as well as La2O3 and Pr5O. 11 Using any one of the powders and MnO2 as raw materials, ball milling is performed according to the metal atomic molar ratio x:y:z:u:v:2, where x+y+z+u+v=1. After drying and grinding, the mixture powder is obtained. The mixture powder is then calcined at high temperature in a muffle furnace under air atmosphere and cooled to room temperature to obtain a three-phase high-entropy ceramic powder material with two spinel structures and one perovskite structure.

3. The preparation method of a spinel-perovskite three-phase high-entropy ceramic powder material as described in claim 2, characterized in that: The conditions for ball milling refer to using a planetary ball mill, using ultrapure water as the ball milling solvent, a ball milling speed of 300~500 r / min, a ball milling time of 5~10 hours, and a ball-to-water mass ratio of 2~5:1:

3.

4. The preparation method of a spinel-perovskite three-phase high-entropy ceramic powder material as described in claim 2, characterized in that: The drying conditions refer to a temperature of 80~100℃ and a drying time of 12~24 hours.

5. The preparation method of a spinel-perovskite three-phase high-entropy ceramic powder material as described in claim 2, characterized in that: The conditions for high-temperature calcination are a calcination temperature of 900~1300℃, a heating rate of 3~5℃ / min, and a calcination time of 4~8 hours.

6. The preparation method of a spinel-perovskite three-phase high-entropy ceramic powder material as described in claim 2, characterized in that: The cooling method is one of furnace cooling, air quenching cooling, and liquid nitrogen quenching cooling.

Images