Rare earth aluminate-based radiation refrigeration ceramic material as well as preparation method and application thereof

Abstract

The invention discloses an aluminate rare earth based radiation refrigeration ceramic material and a preparation method and application thereof, the chemical formula of the material is Y3 (Al1-zMz) 5O12, when M is selected from any one of Fe, Ni and Cu, z is larger than or equal to 0.01 and smaller than or equal to 0.10; when M is selected from Mn, z is 0.05 lt; and z is less than or equal to 0.10. The rare earth aluminate-based radiation refrigeration ceramic material disclosed by the invention has high sunlight reflectivity and atmospheric window emissivity, and can effectively reflect solar radiation, reduce heat absorption and realize an excellent refrigeration effect. In addition, through doping of characteristic metal elements, diversified color characteristics are presented. Therefore, the rare earth aluminate-based radiation refrigeration ceramic material disclosed by the invention can be applied as a radiation refrigeration coating in building outer walls, cloth and outdoor tents.

Description

Technical Field

[0001] The present invention relates to a radiative cooling ceramic material, and particularly to a rare earth aluminate-based radiative cooling ceramic material, a preparation method thereof, and an application thereof. Background Art

[0002] Solar energy irradiates the earth's surface with an energy of 50×10 15 MJ every year. Although we enjoy the huge benefits brought by solar energy, problems such as the heat island effect, energy consumption, and public safety have gradually emerged. As the earth warms up, more and more livable environments are turning into scorching areas.

[0003] Currently, electricity mainly relies on the combustion of coal and natural gas, and traditional cooling technologies such as vapor compression will accelerate the emission of greenhouse gases, further exacerbating global warming. In recent years, radiative cooling technology has received extensive attention due to its advantages of "zero work input" and "no greenhouse gas emissions". Radiative cooling materials need to have a high reflectivity and a high emissivity in the atmospheric window band to reduce the absorption of sunlight heat and enhance the radiation of heat.

[0004] In order to maintain a high reflectivity, current radiative cooling materials (such as alumina, zinc oxide, titanium dioxide, barium sulfate, etc.) are usually white, which leads to the problem of light pollution. Therefore, it is necessary to develop colored radiative cooling materials to replace traditional white materials. Existing color modification methods, such as using organic dyes, are often limited by a low sunlight reflectivity, thus significantly reducing the radiative cooling effect. Therefore, finding new colored radiative cooling materials has become an important task at present.

[0005] It should be noted that the information disclosed in the above background art section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0006] The object of the present invention is to provide a rare earth aluminate-based radiative cooling ceramic material, a preparation method thereof, and an application thereof, and by introducing transition metal elements, a rare earth aluminate-based radiative cooling ceramic material with a high sunlight reflectivity and a high emissivity in the atmospheric window is prepared.

[0007] To achieve the above object, the present invention provides a rare earth aluminate-based radiative cooling ceramic material, and the chemical formula of the material is Y3(Al 1-z M z )5O 12 , wherein M is selected from any one of Fe, Mn, Ni, and Cu; when M is selected from any one of Fe, Ni, and Cu, z takes a value of 0.01≤z≤0.10; when M is selected from Mn, z takes a value of 0.05<z≤0.10.

[0008] The inventor of the present invention has found through a large number of experimental studies that rare earth elements, due to their unique 4f5d electronic structure, show significant potential in the field of radiation cooling. The 4f electronic orbit of rare earth elements is located in the inner layer and is insensitive to changes in the external chemical environment. This stability enables rare earth elements to maintain their optical properties in radiation cooling materials for a long time, and is not easily affected by external factors such as oxidation and temperature changes, thereby improving the reliability and service life of the material. In addition, the 4f-4f and 4f-5d transitions of rare earth elements show unique spectral characteristics, which can efficiently emit and absorb photons within a specific wavelength range. By synthesizing specific rare earth doped materials, it can absorb external photons during radiation cooling and re-emit long-wavelength photons, thereby taking away heat and achieving a cooling effect. In the visible light region, transition metal doped aluminate ions are prone to grouping, with rare earth metal ions as electron acceptors and aluminate ions as ligands. When absorbing enough energy, electronic transitions are prone to change the bandgap width, which is beneficial to the regulation of color and the improvement of optical properties. At the same time, the color characteristics of the ceramic material are changed by adjusting the type and amount of the doping components, so that aluminates doped with different metals have high selectivity in different bands and are applied to different environments to meet the color requirements of radiant cooling in the existing market.

[0009] The rare earth aluminate-based radiation cooling ceramic material Y3 (Al 1-z M z )5O 12 , wherein, when M is selected from Fe, it appears yellow; when M is selected from Mn, it appears brown; when M is selected from Ni, it appears green; and when M is selected from Cu, it appears pink.

[0010] Preferably, the rare earth aluminate-based radiation cooling ceramic material has a garnet structure.

[0011] Preferably, the reflectivity of the rare earth aluminate-based radiation cooling ceramic material to the sunlight band is 80-100%.

[0012] Preferably, the rare earth aluminate-based radiation cooling ceramic material has an emissivity of 90-100% in the atmospheric window band.

[0013] Preferably, the chemical formula of the rare earth aluminate-based radiation cooling ceramic material is Y3(Al 0.9 Fe 0.1 )5O 12 、Y3(Al 0.95 Mn 0.05 )5O 12 、Y3(Al 0.99 Ni 0.01 )5O 12 or Y3(Al 0.99 Cu 0.01 )5O12 。

[0014] The second object of the present invention is to provide a preparation method of the rare earth aluminate-based radiation cooling ceramic material, and the method comprises the following steps: (1) Mixing a Y source, an Al source and an M source and performing the first ball milling; (2) Drying, sieving and tabletting the slurry after the first ball milling to obtain a first green body; (3) Calcining the first green body obtained in step (2) at 1650 °C and holding for heat preservation, and performing the first crushing to obtain the rare earth aluminate-based radiation cooling ceramic material.

[0015] Preferably, the number of calcination times in this method is at least 1 time, and the temperature of each calcination is 1650 °C; after the rare earth aluminate-based radiation cooling ceramic material obtained by calcination is subjected to re-ball milling, drying, sieving and tabletting to obtain a green body, it is calcined and held for heat preservation again, and then crushed to finally obtain the target product, the rare earth aluminate-based radiation cooling ceramic material.

[0016] According to the present invention, the number of calcination times of the solid-phase synthesis method can be multiple times. Multiple calcination times can make the grains of the ceramic more uniform, reduce defects, thereby improving its mechanical strength and wear resistance. At the same time, the crystal structure of the ceramic can be optimized, and its crystallinity and stability can be improved. Preferably, it is 2 times.

[0017] Preferably, in step (1), the molar ratio of the Y source, the Al source, and the M source is 3:(4.5 - 4.95):(0.05 - 0.5); or / and, in step (1), the Y source is selected from yttrium oxide; or / and, in step (1), the Al source is selected from aluminum oxide; or / and, in step (1), the M source is selected from any one of iron oxide, manganese oxide, cuprous oxide, and nickel oxide; or / and, for the first ball milling and the re-ball milling, ball milling is carried out using ethanol as the medium, and other alcohols can also be selected. The present invention does not make a special limitation on the amount of alcohol, as long as the zirconia balls and each raw material in the ball milling tank are immersed; or / and, for the first ball milling and the re-ball milling, the ball milling speeds are each independently 300 - 500 rpm. Exemplarily, the ball milling speeds are 400 rpm and 450 rpm; or / and, for the first ball milling and the re-ball milling, the ball milling times are each independently 1 - 10 h. Exemplarily, the ball milling times are 5 h and 10 h; or / and, for the first ball milling and the re-ball milling, the working mode of ball milling is to intermittently stop for 1 minute after working for 4 minutes; or / and, for the first drying and the re-drying, the drying temperatures are each independently 60 - 80 °C; or / and, for the first drying and the re-drying, the drying times are each independently 10 - 24 h; or / and, for the first sieving and the re-sieving, the mesh aperture sizes of the sieves used are each independently 200 - 400 mesh; or / and, for the first tabletting and the re-tabletting, a briquetting block is used to press the powder into a green body. The pressure of the briquetting block is 5 - 15 MPa, and the diameter of the briquetting block is 10 - 20 mm. Exemplarily, the pressures of the briquetting block are 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, or 10 MPa, and the diameters of the briquetting block are 10 mm, 15 mm, and 20 mm; or / and, for the first tabletting and the re-tabletting, a briquetting block is used to press the powder into a green body. The pressing time of the briquetting block is 20 - 50 s. Exemplarily, the pressing times of the briquetting block are 20 s, 30 s, 40 s, and 50 s; or / and, for the first calcination and the re-calcination, the holding times are each independently 2 - 15 h; or / and, for the first calcination and the re-calcination, the heating rates are each independently 5 - 10 °C / min. Exemplarily, the heating rate is 10 °C / min.

[0018] More preferably, for the first calcination and the re-calcination, the holding times are each independently 2 - 6 h. Exemplarily, the holding times are 2 h, 3 h, 4 h, 5 h, and 6 h.

[0019] The third object of the present invention is to provide a radiation cooling coating containing the rare earth aluminate-based radiation cooling ceramic material described above.

[0020] The fourth object of the present invention is to provide the application of the rare earth aluminate-based radiation cooling ceramic material described above as a radiation cooling coating.

[0021] The rare earth aluminate-based radiative cooling ceramic material of the present invention, its preparation method and application have the following advantages: (1) For the rare earth aluminate-based radiative cooling ceramic material prepared by the present invention, on the one hand, rare earth ions exhibit good optical properties due to their unique electron layers; on the other hand, by doping different rare earth elements, the rare earth aluminate-based radiative cooling ceramic material has polychromatism and extremely high emissivity in the atmospheric window band; (2) For the rare earth aluminate-based radiative cooling ceramic material prepared by the present invention, in the visible light region, transition metal-doped aluminate ions are prone to group formation. Rare earth metal ions act as electron acceptors and aluminate ions act as ligands. When absorbing sufficient energy, electron transitions are prone to occur, thereby changing the band gap width, which is beneficial to color regulation and improvement of optical properties. At the same time, by adjusting the type and quantity of doping components, the color characteristics of the ceramic material are changed, so that aluminates doped with different metals have high selectivity in different bands and are applied to different environments to meet the radiative cooling color requirements of the existing market;

[0022] (3) The present invention uses the solid-phase synthesis method to prepare the rare earth aluminate-based radiative cooling ceramic material. The preparation process of the present invention is simple, the synthesis purity is high, and it can be applied on a large scale; (4) The rare earth aluminate-based radiative cooling ceramic material of the present invention has a high solar reflectivity and an atmospheric window emissivity. The high reflectivity enables the material to effectively reflect solar radiation in the entire solar light band, reducing heat absorption; the high emissivity effectively radiates heat through the atmospheric window, achieving excellent cooling effects. In addition, through doping with characteristic metal elements, diverse color characteristics are presented. This color modification not only enhances the visual attractiveness of the material but also provides greater design flexibility for its application in the construction and decoration fields. Therefore, the rare earth aluminate-based radiative cooling ceramic material of the present invention can be used as a radiative cooling coating in building exteriors, fabrics, and outdoor tents. Description of the Drawings

[0023] Figure 1 is the XRD pattern of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.9 Fe 0.1 )5O 12 obtained by two calcinations in Example 1 of the present invention.

[0024] Figure 2 is the ultraviolet-visible-near-infrared reflectivity spectrum of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.9 Fe 0.1 )5O 12 obtained by two calcinations in Example 1 of the present invention.

[0025] Figure 3 The atmospheric window emissivity spectrum of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.9 Fe 0.1 )5O 12 obtained by two calcinations in Example 1 of the present invention.

[0026] Figure 4 The XRD pattern of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.95 Mn 0.05 )5O 12 obtained by two calcinations in Example 2 of the present invention.

[0027] Figure 5 The ultraviolet-visible-near-infrared reflectivity spectrum of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.95 Mn 0.05 )5O 12 obtained by two calcinations in Example 2 of the present invention.

[0028] Figure 6 The atmospheric window emissivity spectrum of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.95 Mn 0.05 )5O 12 obtained by two calcinations in Example 2 of the present invention.

[0029] Figure 7 The XRD pattern of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.99 NI 0.01 )5O 12 obtained by two calcinations in Example 3 of the present invention.

[0030] Figure 8 The ultraviolet-visible-near-infrared reflectivity spectrum of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.99 Ni 0.01 )5O 12 obtained by two calcinations in Example 3 of the present invention.

[0031] Figure 9 The atmospheric window emissivity spectrum of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.99 Ni 0.01 )5O 12 obtained by two calcinations in Example 3 of the present invention.

[0032] Figure 10 The XRD pattern of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.99 Cu 0.01 )5O 12 obtained by two calcinations in Example 4 of the present invention.

[0033] Figure 11 This is the ultraviolet-visible-near-infrared reflectance spectrum of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.99 Cu 0.01 )5O 12 obtained by two-stage calcination in Example 4 of the present invention.

[0034] Figure 12 This is the emissivity spectrum in the atmospheric window of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.99 Cu 0.01 )5O 12 obtained by two-stage calcination in Example 4 of the present invention. Detailed implementation manners

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] It should be noted that: for those conditions not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For the instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase. For the raw materials and reagents whose manufacturers are not specified, they are all commercially available products or can be prepared by known methods.

[0037] In the present invention, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are only for the sake of simplicity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be regarded as having covered and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions).

[0038] The features mentioned in the present invention can be combined arbitrarily as long as there is no contradiction in the combination of these features. All possible combinations should be considered as the scope described in this specification. Each feature disclosed in the specification can be replaced by any alternative feature that provides the same, equivalent, or similar purpose. Therefore, unless otherwise specified, the disclosed features are only general examples of equivalent or similar features.

[0039] Example 1 A yellow rare earth aluminate-based radiative cooling ceramic powder material, and its preparation method includes the following steps: (1) Weigh 0.003 mol of Y2O3, 0.0045 mol of Al2O3, and 0.0005 mol of Fe2O3 respectively and place them in a 500 mL zirconia ball milling jar. Add 50 mL of ethanol and carry out high-energy ball milling. Control the rotation speed of the ball mill at 450 rpm and ball mill for 5 h. During the ball milling process, there is an intermittent break of 1 minute after every 4 minutes of work; (2) Place the mixture after ball milling in step (1) in an oven and dry it at 60 °C for 24 h. Screen it through a 400-mesh standard sieve, and then press the powder into a block. Set the pressure of the press at 10 MPa and press for 20 s. The diameter of the pressing die is 15 mm; (3) Then put the sample obtained in step (2) into a muffle furnace for calcination. The calcination temperature is 1600 °C, the heating rate is 10 °C / min, and the holding time is 6 h to obtain the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.9 Fe 0.1 )5O 12 ; (4) Crush the rare earth aluminate-based radiative cooling ceramic material obtained in step (3); carry out high-energy ball milling again with ethanol as the medium. Control the rotation speed of the ball mill at 400 rpm and ball mill for 10 h. During the ball milling process, there is an intermittent break of 1 minute after every 4 minutes of work; (5) Place the product obtained in step (4) in an oven and dry it at 65 °C for 24 h. After completion, screen it through a 400-mesh standard sieve and press it into a block again. Set the pressure of the press at 15 MPa and press for 20 s. The diameter of the pressing die is 10 mm. Put the sample into a muffle furnace for sintering. Control the sintering temperature at 1650 °C, the heating rate at 5 °C / min, and the holding time at 5 h. Crush it to obtain the yellow rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.9 Fe 0.1 )5O 12 .

[0040] The XRD of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.9 Fe 0.1 )5O 12 obtained by two calcinations in this Example 1 is as Figure 1 shown. The results show that the rare earth aluminate-based radiative cooling ceramic material prepared in this example has a garnet structure, no extra impurity peaks appear, and the product crystal form is complete.

[0041] As Figure 2 shown, it is the ultraviolet-visible-near-infrared reflectivity spectrum of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.9 Fe 0.1 )5O 12 obtained by two calcinations in this Example 1. FromFigure 2 It can be seen that Y3(Al 0.9 Fe 0.1 )5O 12 has an average reflectivity of 97.65% in the ultraviolet-visible-near-infrared reflectivity band.

[0042] As Figure 3 shown, the emissivity spectrum of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.9 Fe 0.1 )5O 12 obtained in Example 1 after two calcinations is shown. It can be seen from Figure 3 that Y3(Al 0.9 Fe 0.1 )5O 12 has an average emissivity of 93.69% in this band.

[0043] Example 2 A brown rare earth aluminate-based radiative cooling ceramic powder material, the preparation method of which is basically the same as that of Example 1, except that: In step (1), 0.003 mol of Y2O3, 0.00475 mol of Al2O3 and 0.0005 mol of MnO2 are used.

[0044] The brown rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.95 Mn 0.05 )5O 12 is obtained through Example 2.

[0045] The XRD of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.95 Mn 0.05 )5O 12 obtained in Example 2 after two calcinations is as Figure 4 shown. The results show that the rare earth aluminate-based radiative cooling ceramic material prepared in this example has a garnet structure, no extra impurity peaks appear, and the product crystal form is complete.

[0046] As Figure 5 shown, the ultraviolet-visible-near-infrared reflectivity spectrum of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.95 Mn 0.05 )5O 12 obtained in Example 2 after two calcinations is shown. It can be seen from Figure 5 that Y3(Al 0.95 Mn 0.05 )5O 12 has an average reflectivity of 96.33% in the ultraviolet-visible-near-infrared reflectivity band.

[0047] AsFigure 6 As shown, it is the atmospheric window emissivity spectrum of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.95 Mn 0.05 )5O 12 obtained by two calcinations in Example 2. It can be seen from Figure 6 that the average emissivity of Y3(Al 0.95 Mn 0.05 )5O 12 in this wavelength band is 93.55%.

[0048] Example 3 A green rare earth aluminate-based radiative cooling ceramic powder material, its preparation method is basically the same as that of Example 1, the difference is that: In step (1), 0.003 mol of Y2O3, 0.00495 mol of Al2O3 and 0.0001 mol of NiO are used.

[0049] The green rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.99 Ni 0.01 )5O 12 is obtained through Example 3.

[0050] The XRD of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.99 Ni 0.01 )5O 12 obtained by two calcinations in this Example 3 is as shown in Figure 7 . The results show that the rare earth aluminate-based radiative cooling ceramic material prepared in this example is in garnet structure, without extra impurity peaks, and the product crystal form is complete.

[0051] As shown in Figure 8 , it is the ultraviolet-visible-near infrared reflectivity spectrum of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.99 Ni 0.01 )5O 12 obtained by two calcinations in this Example 3. It can be seen from Figure 8 that the average reflectivity of Y3(Al 0.99 Ni 0.01 )5O 12 in the ultraviolet-visible-near infrared reflectivity wavelength band is 97.88%.

[0052] As shown in Figure 9 , it is the atmospheric window emissivity spectrum of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.99 Ni 0.01 )5O 12 obtained by two calcinations in this Example 3. It can be seen from Figure 9It can be seen that Y3(Al 0.99 Ni 0.01 )5O 12 has an average emissivity of 93.69% in this wavelength band.

[0053] Example 4 A pink rare earth aluminate-based radiative cooling ceramic powder material, whose preparation method is basically the same as that of Example 1, the difference lies in: In step (1), 0.003 mol of Y2O3, 0.00495 mol of Al2O3 and 0.00005 mol of Cu2O are used.

[0054] The pink rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.99 Cu 0.01 )5O 12 is obtained through Example 4.

[0055] The XRD of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.99 Cu 0.01 )5O 12 obtained in this Example 4 after two calcinations is as Figure 10 shown. The results show that the rare earth aluminate-based radiative cooling ceramic material prepared in this example is of garnet structure, without extra impurity peaks, and the product crystal form is complete.

[0056] As Figure 11 shown, it is the ultraviolet-visible-near-infrared reflectivity spectrum of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.99 Cu 0.01 )5O 12 obtained in this Example 4 after two calcinations. It can be seen from Figure 11 that Y3(Al 0.99 Cu 0.01 )5O 12 has an average reflectivity of 98.66% in the ultraviolet-visible-near-infrared reflectivity wavelength band.

[0057] As Figure 12 shown, it is the atmospheric window emissivity spectrum of the rare earth aluminate-based radiative cooling ceramic material Y3(Al 0.99 Cu 0.01 )5O 12 obtained in this Example 4 after two calcinations. It can be seen from Figure 12 that Y3(Al 0.99 Cu 0.01 )5O 12 has an average emissivity of 93.17% in this wavelength band.

[0058] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present invention. After those skilled in the art have read the above content, various modifications and alternatives to the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims

1. A rare earth aluminate-based radiation cooling ceramic material, characterized in that: The chemical formula of this material is Y3(Al 1-z M z )5O 12 , wherein M is selected from any one of Fe, Mn, Ni and Cu; When M is selected from any one of Fe, Ni, and Cu, z is 0.01≤z≤0.10; When M is selected from Mn, z is 0.05 <z≤0.10。 2. The rare earth aluminate-based radiation cooling ceramic material according to claim 1, characterized in that: The rare earth aluminate-based radiation cooling ceramic material has a garnet structure.

3. The rare earth aluminate-based radiation cooling ceramic material according to claim 1, characterized in that: The reflectivity of the rare earth aluminate-based radiation cooling ceramic material to the sunlight band is 80-100%.

4. The rare earth aluminate-based radiation cooling ceramic material according to claim 1, characterized in that: The rare earth aluminate-based radiation cooling ceramic material has an emissivity of 90-100% in the atmospheric window band.

5. The rare earth aluminate-based radiation cooling ceramic material according to claim 1, characterized in that: The chemical formula of the rare earth aluminate-based radiation cooling ceramic material is Y3(Al 0.9 Fe 0.1 )5O 12 、Y3(Al 0.95 Mn 0.05 )5O 12 、Y3(Al 0.99 Ni 0.01 )5O 12 or Y3(Al 0.99 Cu 0.01 )5O 12 .

6. The method for preparing the rare earth aluminate-based radiation cooling ceramic material according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: (1) Mix the Y source, Al source and M source for the first ball milling; (2) drying, sieving and tableting the slurry after the first ball milling to obtain a first embryo body; (3) The first embryo body obtained in step (2) is subjected to a first calcination at 1650° C. and heat preservation, and is crushed for a first time to obtain a rare earth aluminate-based radiation cooling ceramic material.

7. The preparation method according to claim 6, characterized in that: The calcination is performed at least once, and the temperature of each calcination is 1650°C; The calcined rare earth aluminate-based radiation cooling ceramic material is ball-milled again, dried, sieved and tabletted to obtain a green body, which is then calcined again, kept warm and crushed to finally obtain the target product, the rare earth aluminate-based radiation cooling ceramic material.

8. The preparation method according to claim 7, characterized in that: In step (1), the molar ratio of the Y source, the Al source and the M source is 3: (4.5-4.95): (0.05-0.5); or / and, in step (1), the Y source is selected from yttrium oxide; Or / and, in step (1), the Al source is selected from alumina; or / and, in step (1), the M source is selected from any one of iron oxide, manganese oxide, cuprous oxide and nickel oxide; Or / and, the first ball milling and the second ball milling are performed using ethanol as a medium; Or / and, the first ball milling and the second ball milling are each independently performed at a ball milling speed of 300-500 rpm; Or / and, the first ball milling and the second ball milling have a ball milling time of 1 to 10 h respectively independently; Or / and, the first ball milling and the second ball milling are performed in a working mode of 1 minute rest after every 4 minutes of working; Or / and, the first drying and the second drying are each independently at a drying temperature of 60-80°C; Or / and, the first drying and the second drying, the drying time is independently 10 to 24 hours; Or / and, the first screening and the second screening use sieves with mesh sizes of 200-400 meshes each independently; or / and, the first tableting and the second tableting are performed by pressing the powder into an embryonic body by briquetting, the briquetting pressure is 5-15 MPa, and the diameter of the briquetting is 10-20 mm; or / and, the first tableting and the second tableting are performed by pressing the powder into an embryonic body by briquetting, and the pressing time of the briquetting is 20 to 50 s; Or / and, the holding time of the first calcination and the second calcination is independently 2 to 15 hours; Or / and, the heating rates of the first calcination and the second calcination are independently 5-10°C / min.

9. A radiation cooling coating comprising the rare earth aluminate-based radiation cooling ceramic material according to any one of claims 1 to 5.

10. Use of the rare earth aluminate-based radiation cooling ceramic material according to any one of claims 1 to 5 as a radiation cooling coating.

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