High-entropy calcium titanate perovskite infrared radiation material and preparation method thereof

Abstract

The present application relates to a kind of high-entropy calcium ferrite perovskite infrared radiation material, the chemical formula of the high-entropy calcium ferrite perovskite infrared radiation material is AB03;A site is any five elements in rare earth elements La, Pr, Ca, Ce, Gd, Sm, Nd, Dy, and 12 oxygen ions are coordinated, located in the cavity formed by octahedron;B is transition metal element Fe, and cation is formed octahedral coordination with six oxygen ions.Simultaneously, the preparation method of the high-entropy calcium ferrite perovskite infrared radiation material is disclosed.The high-entropy calcium ferrite perovskite infrared radiation material described in the present application has excellent thermal stability under the condition of 0.78~16 μm waveband infrared emissivity 0.85~0.88, 24 hours 1300 DEG C, can be applied to power station boiler, aerospace, industrial kiln and the high-temperature radiation heat transfer and heat protection field of other high-temperature radiation heat transfer and heat protection field.

Description

Technical Field

[0001] This invention relates to the field of infrared radiation materials, and more particularly to a high-entropy perovskite infrared radiation material and its preparation method. Background Technology

[0002] Thermal radiation involves the design of engineering hot surfaces, which can effectively transfer heat from the surface of one hot object to another without contact. At temperatures above 1000°C, radiative heat transfer accounts for over 80% of total heat transfer. This technology offers energy-saving and efficiency-enhancing benefits as well as thermal protection in numerous fields, including industrial kilns, high-temperature boilers, and spacecraft.

[0003] Currently, materials such as SiC, SiB, cordierite, spinel, and perovskite possess good infrared radiation performance and thermal stability, and have been used as infrared radiation materials. For example, perovskite-type LaFeO3 oxide has a melting point of up to 1900℃ and exhibits good high-temperature stability. However, this material has a relatively low infrared emissivity in the 3–5 μm wavelength range. According to Wien's displacement law and Planck's law, under high-temperature conditions, radiation energy is mainly concentrated in the 1–5 μm wavelength range. By doping rare earth elements or alkaline earth metal elements (with valences of +1, +2, and +3) at the A-site, or by doping transition metal ions (with valences of +3, +4, and +5) at the B-site, the emissivity in the 3–5 μm wavelength range can be improved. However, the doping process may introduce impurities, reducing oxidation resistance at high temperatures and leading to infrared emissivity decay, thus shortening the service life.

[0004] In recent years, high-entropy materials have attracted widespread research interest in fields such as energy storage and conversion. High-entropy materials possess high configurational entropy, which can offset the increase in enthalpy, reduce the Gibbs free energy of the system, and form a single-phase solid solution structure. Furthermore, the multi-component nature provides a prerequisite for optimizing the functional properties of the material. However, there are relatively few reports on high-entropy materials in the field of infrared radiation. In 2022, Zhang Zongtao et al. applied for Chinese invention patent CN 114573345 A, "Preparation Method and Application of Perovskite-type High-entropy High-emissivity Ceramic Coating Solution," which used the sol-gel method to prepare a perovskite-type high-entropy high-emissivity ceramic coating solution. However, the preparation process is relatively complex, and it mainly introduces transition metals at the B-site to increase emissivity, which is not conducive to improving the high-temperature thermal stability of the material. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a high-entropy perovskite infrared radiation material with improved high-temperature thermal stability.

[0006] Another technical problem to be solved by the present invention is to provide a method for preparing the high-entropy perovskite infrared radiation material.

[0007] To address the aforementioned problems, the present invention provides a high-entropy perovskite infrared radiation material, characterized in that: the chemical formula of the high-entropy perovskite infrared radiation material is ABO3; the A site is any five rare earth elements selected from La, Pr, Ca, Ce, Gd, Sm, Nd, and Dy, coordinated with 12 oxygen ions and located within a cavity composed of octahedra; the B site is a transition metal element Fe, with the cation coordinated with six oxygen ions to form an octahedral structure.

[0008] The high-entropy perovskite infrared radiation material has an infrared emissivity of 0.85 to 0.88 in the 0.78 to 16 μm band.

[0009] The preparation method of the high-entropy perovskite infrared radiation material described above is characterized by: the method referring to the use of La2O3 and Pr6O 11 Using any five of the following powders—CaO, Ce2O3, Gd2O3, Sm2O3, Nd2O3, and Dy2O3—and Fe2O3 as raw materials, the mixture is ball-milled and mixed in a metal atomic molar ratio of 1:1:1:1:1:5. After drying and grinding, the mixture powder is obtained. The mixture powder is then calcined at high temperature in a muffle furnace, cooled, and ground to obtain a high-entropy perovskite infrared radiation material.

[0010] The conditions for ball milling and mixing refer to wet ball milling using a planetary ball mill, with a milling speed of 300~500 r / min, a milling time of 12~24 hours, and a mass ratio of ball material to anhydrous ethanol of 2~5:1:3.

[0011] The conditions for high-temperature calcination are a calcination temperature of 1000~1500℃, a heating rate of 3~5℃ / min, and a calcination time of 4~10 hours.

[0012] The cooling method is one of furnace cooling, air quenching cooling, and liquid nitrogen quenching cooling.

[0013] Compared with the prior art, the present invention has the following advantages: 1. The high-entropy perovskite infrared radiation material of this invention has the chemical formula ABO3; the A-site is doped with multiple rare earth elements, coordinated with 12 oxygen ions, located within a cavity formed by octahedrons; B is a transition metal element Fe, with the cation coordinated with six oxygen ions to form an octahedron. This structure can accommodate multiple cations, providing ample room for optimization of infrared radiation performance, and exhibits excellent structural stability, making it suitable for high-temperature and corrosive environments.

[0014] 2. This invention employs an entropy-driven high-entropy stabilization strategy to synthesize a high-entropy ferric acid material with a single perovskite structure. This material is characterized by a single phase, high purity, small particle size, and uniform elemental distribution.

[0015] 3. The high-entropy perovskite infrared radiation material described in this invention exhibits both high-entropy and hysteresis diffusion effects, demonstrating excellent high-temperature stability in air. After a prolonged thermal stability experiment at 1300℃ for 24 hours, no impurity peaks appeared on the XRD pattern, and the infrared emissivity variation ranged only 0.01, indicating superior thermal stability. Furthermore, this material also exhibits good resistance to acid and alkali corrosion.

[0016] 4. In the high-entropy perovskite infrared radiation material of this invention, multiple rare earth elements form multiple impure f-electron intermediate energy levels, which is beneficial for reducing the band gap. The band gap of the material of this invention is 1.25 eV, which is beneficial for improving the infrared radiation performance in the near-infrared region. At the same time, due to the size difference of the doping elements, a lattice distortion effect is caused, which increases the absorption of lattice vibrations, resulting in a higher infrared emissivity in the mid-infrared region, which can improve the infrared heat transfer efficiency under high temperature conditions. Its infrared emissivity in the 0.78~16 μm band is 0.85~0.88. Therefore, this high-entropy perovskite infrared radiation material can be applied to high-temperature radiation heat transfer and thermal protection fields such as power plant boilers, aerospace, and industrial kilns.

[0017] 5. This invention employs a simple mechanical wet ball milling and solid-phase synthesis calcination method to prepare high-entropy perovskite infrared radiation materials, which are suitable for industrial-scale production. Attached Figure Description

[0018] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0019] Figure 1 This is Embodiment 1 of the present invention (La) 0.2 Ca 0.2 Pr 0.2 Ce 0.2 Sm 0.2 XRD pattern of FeO3.

[0020] Figure 2 This is Embodiment 2 of the present invention (La) 0.2 Ca 0.2 Pr 0.2 Ce 0.2 Nd 0.2 XRD pattern of FeO3.

[0021] Figure 3 This is Embodiment 2 of the present invention (La) 0.2 Ca 0.2 Pr 0.2 Ce 0.2 Nd 0.2 Infrared radiation spectrum of FeO3 in the 0.78~16 μm band.

[0022] Figure 4This is embodiment 3 of the present invention (La) 0.2 Ca 0.2 Pr 0.2 Ce 0.2 Gd 0.2 XRD pattern of FeO3.

[0023] Figure 5 This is embodiment 4 of the present invention (La) 0.2 Ca 0.2 Pr 0.2 Ce 0.2 Dy 0.2 XRD pattern of FeO3. Detailed Implementation

[0024] A high-entropy perovskite infrared radiation material, the chemical formula of which is ABO3; A site is any five rare earth elements La, Pr, Ca, Ce, Gd, Sm, Nd and Dy, coordinated with 12 oxygen ions, located in a cavity composed of octahedra; B is a transition metal element Fe, the cation is coordinated with six oxygen ions to form an octahedral structure.

[0025] The high-entropy perovskite infrared radiation material has an infrared emissivity of 0.85 to 0.88 in the 0.78 to 16 μm band.

[0026] Its preparation method: This method refers to using La2O3 and Pr6O 11 Using any five of the following powders—CaO, Ce₂O₃, Gd₂O₃, Sm₂O₃, Nd₂O₃, and Dy₂O₃—and Fe₂O₃ as raw materials, wet ball milling is performed using a planetary ball mill at a metal atomic molar ratio of 1:1:1:1:1:5. The milling speed is 300–500 r / min, and the milling time is 12–24 hours. The mass ratio (g / g) of the ball material to anhydrous ethanol is 2–5:1:3. After ball milling and mixing, the mixture is dried at 80–100℃ and then ground to obtain a powder. The powder is then calcined in a muffle furnace at a high temperature of 1000–1500℃, a heating rate of 3–5℃ / min, and a calcination time of 4–10 hours. After calcination, the mixture is cooled to room temperature using one of the following methods: furnace cooling, air quenching, or liquid nitrogen quenching. Finally, it is ground to obtain the high-entropy perovskite infrared radiation material.

[0027] Example 1: A method for preparing a high-entropy perovskite infrared radiation material: According to the metal atomic molar ratio of 1:1:1:1:1:5, 1 mol of CaO and 1 mol of Pr6O were weighed out respectively. 11Zirconia balls (1 mol), La₂O₃ (1 mol), Ce₂O₃ (1 mol), Sm₂O₃ (1 mol), and Fe₂O₃ (5 mol) powders were used as raw materials. The zirconia balls, raw materials, and anhydrous ethanol were added to a planetary ball mill at a mass ratio (g / g) of 2:1:3. The milling process was repeated for 1 hour at 300 r / min, followed by a 10-min pause. This constituted one milling cycle. After a 10-min pause, the milling was repeated for another hour at 300 r / min, for a total of 24 hours. The mixture was dried at 80-100℃ after milling and then ground to obtain a powder. This powder was then calcined in a muffle furnace at 1000℃ with a heating rate of 3℃ / min for 8 hours. After calcination, the mixture was quenched in liquid nitrogen and cooled to room temperature. Finally, it was ground to obtain a single-phase (La₂O₃)₂O₃ powder. 0.2 Ca 0.2 Pr 0.2 Ce 0.2 Sm 0.2 FeO3 high-entropy perovskite infrared radiation material.

[0028] Figure 1 As described in Example 1 (La) 0.2 Ca 0.2 Pr 0.2 Ce 0.2 Sm 0.2 The XRD pattern of the high-entropy perovskite ferrite infrared radiation material is shown. The spectrum is in excellent agreement with the LaFeO3 spectrum (PDF#75-0439) with perovskite structure in the ICDD database, indicating that the high-entropy perovskite ferrite infrared radiation material prepared in this embodiment has a perovskite structure.

[0029] Regarding the obtained (La) 0.2 Ca 0.2 Pr 0.2 Ce 0.2 Sm 0.2 Infrared radiation performance and thermal stability evaluation of FeO3 high-entropy perovskite infrared radiation material: Test method: The reflectance spectra in the 0.78~2.5μm and 2.5~16μm bands were measured using a Lambda 950 UV-Vis-NIR spectrophotometer (with a 150mm integrating sphere) from the United States and a Bruker Tensor 27 infrared spectrometer (with an integrating sphere) from Germany.

[0030] The high-entropy perovskite infrared radiation material was placed in an air atmosphere in a box furnace and subjected to a long-term thermal stability test at 1300℃ for 24 hours.

[0031] The amount of test sample used was 0.2g.

[0032] The results showed that the infrared emissivity of the high-entropy perovskite infrared radiation material was 0.856 in the 0.78~16 μm band; after thermal stability experiments, its infrared emissivity in the 0.78~16 μm band was measured to be 0.849.

[0033] Example 2: A method for preparing a high-entropy perovskite infrared radiation material: According to the metal atomic molar ratio of 1:1:1:1:1:5, 1 mol of CaO and 1 mol of Pr6O were weighed out respectively. 11 Zirconia balls (1 mol), La₂O₃ (1 mol), Ce₂O₃ (1 mol), Nd₂O₃ (1 mol), and Fe₂O₃ (5 mol) powders were used as raw materials. The zirconia balls, raw materials, and anhydrous ethanol were added to a planetary ball mill at a mass ratio (g / g) of 3:1:3. The milling process was repeated for 1 hour at 500 r / min, followed by a 10-min pause. This constituted one milling cycle. After a 10-min pause, the milling was repeated for another hour at 500 r / min, for a total of 12 hours. The mixture was dried at 80-100℃ after milling and then ground to obtain a powder. This powder was then calcined in a muffle furnace at 1300℃ with a heating rate of 3℃ / min for 6 hours. After calcination, the mixture was air-quenched and cooled to room temperature. Finally, it was ground to obtain a single-phase (La₂O₃) powder. 0.2 Ca 0.2 Pr 0.2 Ce 0.2 Nd 0.2 FeO3 high-entropy perovskite infrared radiation material.

[0034] Figure 2 As described in Example 2 (La) 0.2 Ca 0.2 Pr 0.2 Ce 0.2 Nd 0.2 The XRD pattern of the high-entropy perovskite ferrite infrared radiation material is shown. The spectrum is in excellent agreement with the LaFeO3 spectrum (PDF#75-0439) with perovskite structure in the ICDD database, indicating that the high-entropy perovskite ferrite infrared radiation material prepared in this embodiment is a single-phase solid solution with perovskite structure.

[0035] Regarding the obtained (La) 0.2 Ca 0.2 Pr 0.2 Ce 0.2 Nd 0.2 Infrared radiation performance and thermal stability evaluation of FeO3 high-entropy perovskite infrared radiation material: The testing method and the amount of test sample used are the same as in Example 1.

[0036] The results show that the infrared emissivity of this high-entropy perovskite infrared radiation material is 0.88 in the 0.78–16 μm wavelength range. Figure 3 As shown, this indicates that it has a high infrared emissivity in this band.

[0037] After thermal stability experiments, its infrared emissivity in the range of 0.78–16 μm was measured to be 0.872.

[0038] Example 3: A method for preparing a high-entropy perovskite infrared radiation material: According to the metal atomic molar ratio of 1:1:1:1:1:5, 1 mol of CaO and 1 mol of Pr6O were weighed out respectively. 11 Zirconia balls (1 mol), La₂O₃ (1 mol), Ce₂O₃ (1 mol), Gd₂O₃ (1 mol), and Fe₂O₃ (5 mol) powders were used as raw materials. The zirconia balls, raw materials, and anhydrous ethanol were added to a planetary ball mill at a mass ratio (g / g) of 4:1:3. The milling was performed for 1 hour at 300 r / min, followed by a 10-min pause. This constituted one milling cycle. After a 10-min pause, the milling was repeated for another hour at 300 r / min, for a total of 12 hours. The mixture was dried at 80-100℃ after milling and then ground to obtain a powder. This powder was then calcined in a muffle furnace at 1200℃ with a heating rate of 4℃ / min for 10 hours. After calcination, the mixture was cooled to room temperature in the furnace and finally ground to obtain single-phase (La₂O₃)₂O₃. 0.2 Ca 0.2 Pr 0.2 Ce 0.2 Gd 0.2 FeO3 high-entropy perovskite infrared radiation material.

[0039] Figure 4 As described in Example 3 (La) 0.2 Ca 0.2 Pr 0.2 Ce 0.2 Gd 0.2 The XRD pattern of the high-entropy perovskite ferrite infrared radiation material is shown. The spectrum is in excellent agreement with the LaFeO3 spectrum (PDF#75-0439) with perovskite structure in the ICDD database, indicating that the high-entropy perovskite infrared radiation material prepared in this embodiment is a single-phase solid solution with a perovskite structure.

[0040] Regarding the obtained (La) 0.2 Ca 0.2 Pr 0.2 Ce 0.2 Gd 0.2Infrared radiation performance and thermal stability evaluation of FeO3 high-entropy perovskite infrared radiation material: The testing method and the amount of test sample used are the same as in Example 1.

[0041] The results showed that the infrared emissivity of this high-entropy perovskite infrared radiation material was 0.855 in the 0.78–16 μm band. After thermal stability experiments, its infrared emissivity in the 0.78–16 μm band was measured to be 0.848.

[0042] Example 4: A method for preparing a high-entropy perovskite infrared radiation material: According to the metal atomic molar ratio of 1:1:1:1:1:5, 1 mol of CaO and 1 mol of Pr6O were weighed out respectively. 11 Zirconia balls (1 mol), La₂O₃ (1 mol), Ce₂O₃ (1 mol), Dy₂O₃ (1 mol), and Fe₂O₃ (5 mol) powders were used as raw materials. The zirconia balls, raw materials, and anhydrous ethanol were added to a planetary ball mill at a mass ratio (g / g) of 5:1:3. The milling process was repeated for 1 hour at 400 r / min, followed by a 10-min pause. This constituted one milling cycle. After 10 minutes, the milling was repeated for another hour at 400 r / min, for a total of 10 hours. The mixture was dried at 80-100℃ after milling and then ground to obtain a powder. This powder was then calcined in a muffle furnace at 1500℃ with a heating rate of 5℃ / min for 4 hours. After calcination, the mixture was air-quenched and cooled to room temperature. Finally, it was ground to obtain a single-phase (La₂O₃) powder. 0.2 Ca 0.2 Pr 0.2 Ce 0.2 Dy 0.2 FeO3 high-entropy perovskite infrared radiation material.

[0043] Figure 5 As described in Example 4 (La) 0.2 Ca 0.2 Pr 0.2 Ce 0.2 Dy 0.2 The XRD pattern of the high-entropy perovskite ferrite infrared radiation material is shown. The spectrum is in excellent agreement with the LaFeO3 spectrum (PDF#75-0439) with perovskite structure in the ICDD database, indicating that the high-entropy perovskite ferrite infrared radiation material prepared in this embodiment is a single-phase solid solution with perovskite structure.

[0044] Regarding the obtained (La) 0.2 Ca 0.2 Pr 0.2 Ce 0.2 Dy 0.2Infrared radiation performance and thermal stability evaluation of FeO3 high-entropy perovskite infrared radiation material: The testing method and the amount of test sample used are the same as in Example 1.

[0045] The results showed that the infrared emissivity of this high-entropy perovskite infrared radiation material was 0.858 in the 0.78–16 μm band. After thermal stability experiments, its infrared emissivity in the 0.78–16 μm band was measured to be 0.850.

[0046] 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 high-entropy calcium titanate perovskite infrared radiation material, characterized in that: The chemical formula of this high-entropy perovskite infrared radiation material is ABO3; the A site is composed of four elements, La, Pr, Ca, and Ce, as well as one element from Gd, Sm, Nd, and Dy, which are coordinated with 12 oxygen ions and located in a cavity composed of octahedra; the molar ratio of the five elements at the A site is 1:1:1:1:1; B is the transition metal element Fe, whose cation is coordinated with six oxygen ions to form octahedra; the infrared emissivity of this high-entropy perovskite infrared radiation material is 0.85~0.88 in the 0.78~16μm band.

2. The preparation method of the high-entropy calcium titanate perovskite infrared radiation material according to claim 1, characterized in that: The method is to use La2O3, Pr6O 11 , CaO, Ce2O3 four kinds of powder, and any one of Gd2O3, Sm2O3, Nd2O3, Dy2O3 powder and Fe2O3 as raw materials, ball milling is carried out according to the molar ratio of metal atoms 1:1:1:1:1:5, and then the mixture powder is obtained after drying and grinding; the mixture powder is calcined at high temperature in a muffle furnace, cooled and ground, and then the high-entropy calcium titanate perovskite infrared radiation material is obtained.

3. The preparation method of the high-entropy calcium titanate perovskite infrared radiation material according to claim 2, characterized in that: The conditions for ball milling and mixing refer to wet ball milling using a planetary ball mill, with a milling speed of 300~500 r / min, a milling time of 12~24 hours, and a mass ratio of ball material to anhydrous ethanol of 2~5:1:

3.

4. The preparation method of the high-entropy calcium titanate perovskite infrared radiation material according to claim 2, characterized in that: The conditions for high-temperature calcination are a calcination temperature of 1000~1500℃, a heating rate of 3~5℃ / min, and a calcination time of 4~10 hours.

5. The preparation method of the high-entropy calcium titanate perovskite infrared radiation material according to claim 2, characterized in that: The cooling method is one of furnace cooling, air quenching cooling, and liquid nitrogen quenching cooling.

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