Doped M-phase VO2 core-shell particle, intelligent radiation coating and preparation method

Abstract

The invention provides a doped M-phase VO2 core-shell particle, an intelligent radiation coating and a preparation method. The intelligent radiation coating comprises a substrate layer and a resin layer, flaky doped VO2 (M) core-shell particles which are horizontally and directionally arranged are uniformly dispersed on the upper surface of the resin layer; the core material of the sheet-shaped doped VO2 (M) core-shell particle is sheet-shaped aluminum powder, the middle layer is an X material, the surface layer is a doped VO2 shell layer, and the doped VO2 (M) core-shell particle Al (at) X (at) VO2 (M) is used for realizing conversion between infrared light reflection and absorption performance; incident infrared waves cause resonance response, so that the absorption of the coating is enhanced, the corresponding emissivity is enhanced, and the refrigeration effect is achieved. The device has the characteristics of intelligent dynamic temperature control, simple structure, convenience in large-area preparation, zero energy consumption and the like, and is of great significance in solving the problem of excessive refrigeration and relieving the urban heat island effect. Moreover, the method also has application potential in the fields of infrared camouflage and the like.

Description

Technical Field

[0001] The invention relates to an intelligent radiation coating and a preparation method thereof, and belongs to the field of photothermal regulation and phase change temperature control. Background Art

[0002] With the continuous acceleration of urbanization, the urban heat island effect is becoming increasingly severe, which not only leads to a continuous increase in the temperature inside the city, but also causes a sharp increase in the refrigeration energy consumption used to regulate the indoor temperature. Traditional refrigeration methods, based on the principles of heat convection and heat conduction, can effectively reduce the temperature, but also bring serious problems such as high energy consumption, environmental pollution and greenhouse gas emissions. These drawbacks not only aggravate the urban heat island effect, but also form a vicious cycle that is difficult to break, causing a continuous negative impact on the environment. Therefore, how to solve this environmental problem has become an important issue that needs urgent attention in contemporary society.

[0003] In this context, radiative cooling technology, as an innovative thermal management method, provides new possibilities for solving environmental problems with its unique advantages of zero energy consumption and zero emissions. Unlike traditional refrigeration methods, radiative cooling technology abandons the dependence on electricity, refrigerants and mechanical components, but achieves natural heat dissipation by directly emitting infrared waves to the outside world. This process does not require the intervention of any medium, showing extremely high environmental friendliness and application potential. Not only that, radiative cooling technology has even expanded to the space field, providing efficient cooling solutions for spacecraft, demonstrating its wide application prospects under different environmental conditions. However, although radiative cooling technology has entered the commercialization stage, its products still face a key challenge - the phenomenon of over-cooling. In winter or when no additional cooling is required, passive radiative cooling equipment cannot intelligently sense and adapt to changes in ambient temperature, and continuously radiates heat outward, which not only increases the burden of heating, but also causes energy waste. This limitation limits the actual application effect of radiative cooling technology in alleviating the urban heat island effect.

[0004] In order to overcome this challenge, future development should focus on improving the intelligence level of radiant cooling devices. Variable emissivity (radiation) intelligent temperature control materials can automatically change their own radiation properties according to internal and external environment / temperature changes, realize intelligent regulation of heat transfer between the external environment, and achieve on-demand cooling. In this way, it can not only effectively reduce the urban heat island burden, but also promote the efficient use and sustainable development of energy, and provide technical support for building a greener and more energy-saving urban environment. At the same time, this also opens up broad prospects for the application of radiant cooling technology in more fields, making it an important force in promoting social sustainable development. Summary of the invention

[0005] In view of the shortcomings of the prior art mentioned above, the purpose of the present invention is to provide an intelligent radiation coating and a preparation method thereof to address the problem that the radiation characteristics of traditional radiation refrigeration materials are fixed and cannot be changed with changes in the environment. By coating VO2 with thermoinduced phase change properties on flaky aluminum powder and further preparing an Al@X@VO2 coating with directional floating arrangement characteristics, variable emissivity modulation performance in the infrared band (2.5-14μm) can be achieved (the emissivity increases with increasing temperature), thereby obtaining an intelligent coating material with adjustable thermal control characteristics.

[0006] To achieve the above-mentioned purpose of the invention, the technical solution of the present invention is as follows:

[0007] The first object of the present invention is to provide a smart radiation coating, comprising a substrate layer 5 and a resin layer 1 above the substrate layer 5; the upper surface of the resin layer 1 is uniformly dispersed with horizontally oriented flaky doped VO2(M) core-shell particles Al@X@VO2(M);

[0008] The flaky doped VO2(M) core-shell particle Al@X@VO2(M) has a core material of flaky aluminum powder 2 with a reflectivity greater than 90%, an intermediate layer of X material 3 with an infrared transmittance greater than 95%, and a surface layer of doped VO2 shell 4, wherein the X material 3 is calcium fluoride, zinc sulfide, zinc selenide or barium fluoride.

[0009] Horizontally oriented doped VO2(M) core-shell particles Al@X@VO2(M) are used to achieve the transition between infrared light reflection and absorption properties;

[0010] When the temperature is lower than the phase transition temperature, the transmittance of VO2 is enhanced, and the reflectivity of the flaky aluminum powder reduces the emissivity of the coating. When the temperature is higher than the phase transition temperature, the VO in the doped VO2 (M) core-shell particles x The shell layer transforms into M phase, i.e., metal phase, forming a metal-dielectric-metal "sandwich structure". The incident infrared wave causes a resonant response, resulting in enhanced absorption of the coating and corresponding enhanced emissivity, achieving a cooling effect.

[0011] As a preferred embodiment, the particle size of the flaky aluminum powder 2 is 5 to 15 μm;

[0012] And / or the shell thickness of the X material 3 is 300nm-1000nm.

[0013] As a preferred embodiment, in the intelligent radiation coating, the VO2 shell layer 4 has a thickness of 20nm-60nm.

[0014] As a preferred embodiment, in the smart radiation coating, the VO2 shell layer 4 is doped with tungsten, molybdenum and boron elements to reduce its phase transition temperature.

[0015] As a preferred embodiment, in the intelligent radiation coating, the base layer 5 is a copper sheet, a flexible tin foil, a textile cloth, a steel plate or an aluminum alloy plate.

[0016] The second object of the present invention is to provide a method for preparing doped M-phase VO2 core-shell particles, comprising the following steps:

[0017] Step 1, prepare flaky aluminum powder with a particle size of 5 to 15 μm for later use;

[0018] Step 2: by atomic layer deposition, by controlling the reaction time, coating the flaky aluminum powder with a material X having a thickness of 300 nm to 1000 nm, to obtain flaky Al@X core-shell particles;

[0019] Step 3: Prepare Al@X@VO2 core-shell particles by atomic layer deposition:

[0020] (3.1) Place the Al@X core-shell particles obtained in step 2 into the reaction chamber of the atomic deposition equipment, raise the chamber temperature to the set value, fill with argon gas and maintain a certain pressure, stir the powder by rotating the chamber, and start growing the coating layer by atomic layer deposition ALD:

[0021] (3.2) First, introduce the vanadium source and dopant for a certain period of time, and after they fully react with the –OH on the surface of the Al@X core-shell particle substrate, introduce the carrier gas N2 to remove the byproduct methane generated in this part of the reaction;

[0022] (3.3) Then, water vapor is introduced into the cavity to allow it to fully react with the –CH3 on the surface. Then, carrier gas N2 is introduced again to remove the byproduct CH4. This is one cycle. By setting different numbers of cycles, Al@X@VOx core-shell particles with different shell thicknesses can be obtained.

[0023] Step 4: Prepare Al@X@VO x The particles are calcined in a certain atmosphere to promote VO x The shell layer transforms to the M phase to obtain doped VO2(M) core-shell particles;

[0024] The atmosphere calcination in step 4 is divided into two stages: the first stage is carried out at 550° C. for 2 hours under nitrogen with a purity of 99.99%,

[0025] The second stage is to keep warm at 400-650℃ for 10-30min under the condition of oxygen partial pressure RO2=VO2 / (VO2+VN2)=2.5%~10%.

[0026] As a preferred embodiment, in the method for preparing doped M-phase VO2 core-shell particles, the chamber temperature in step (3.1) is set to 150-200°C;

[0027] And / or in step (3.2), the vanadium source is triisopropoxy vanadium oxide, and the dopant is ammonium molybdate, sodium tungstate or boric acid.

[0028] And / or the cycle period in step (3.3) is 400-2000 times.

[0029] The third object of the present invention is to provide a doped M-phase VO2 core-shell particle obtained by the above-mentioned preparation method.

[0030] A fourth object of the present invention is to provide a method for preparing a smart radiation coating, which comprises:

[0031] First, take a certain amount of compound solvent, add a resin with a solid content of 50% in the compound solvent and stir evenly in a dispersant; secondly, add a certain amount of doped M-phase VO2 core-shell particles Al@X@VO2 obtained by the preparation method of claim 6 or 7 and a certain amount of floating agent and dispersant and continue to stir evenly to obtain a spray slurry, wherein the solid content of the doped M-phase VO2 core-shell particles Al@X@VO2 is 20% to 50%; the mass ratio of doped M-phase VO2 core-shell particles: floating agent: dispersant is 5:1:1, and finally the smart radiation coating is obtained by spraying on the substrate.

[0032] As a preferred embodiment, in the preparation method of the intelligent radiation coating, the components of the compound solvent are ethyl acetate: butyl acetate: xylene = 6:3:4 in terms of mass ratio;

[0033] And / or the resin is acrylic resin, silicone resin, styrene, polyethylene or polystyrene.

[0034] And / or the floating agent is oleic acid;

[0035] And / or the dispersant is Hemmings dispersant 904S.

[0036] Beneficial Effects

[0037] (1) Traditional radiation refrigeration materials can basically only guarantee a certain cooling effect, but cannot have a heat preservation function at the same time. Therefore, they can only be used in time periods with relatively high temperatures. When the temperature is low, over-cooling will occur. The intelligent radiation coating provided by the present invention has the functions of cooling, heat preservation and waterproofing at the same time, and can be used in all seasons, which is more practical.

[0038] (2) The intelligent radiation coating proposed in the present invention avoids the multi-layer film structure commonly used in current VO2 intelligent radiation device materials, which is conducive to reducing the difficulty of optical performance design. In terms of application design, compared with the thin film method, the coating process is simple, convenient and fast, and the advantages are more obvious. In addition, it can be applied to the surfaces of various types of substrates such as stainless steel plates, fabrics, epoxy boards, etc., and has waterproof and heat preservation functions, and excellent radiation cooling effect.

[0039] (3) The present invention arranges the VO2 core-shell particles uniformly and horizontally on the surface of the resin. At low temperatures, VO2 is highly permeable, and the high reflectivity of the flaky aluminum powder makes the emissivity of the coating low. At high temperatures (greater than the phase transition temperature), vanadium dioxide is in a metallic phase, forming a metal-medium-metal "sandwich structure". The incident infrared waves will cause a resonant response, resulting in enhanced absorption of the coating, and corresponding enhanced emissivity, achieving the effect of high-temperature refrigeration. Therefore, the intelligent radiation coating of the present invention radiates energy to the outside when the temperature is high, and hardly radiates energy to the outside when the temperature is low, thereby achieving the purpose of intelligent temperature control and dynamic refrigeration, and is not affected by the resin type (high infrared absorption characteristics).

[0040] (4) The present invention mainly adopts the atomic layer deposition method to prepare the shell material in the VO2 core-shell particles. This method can accurately control the thickness of the shell layer by controlling the cyclic growth period, thereby greatly optimizing and controlling the infrared modulation performance of the coating, thereby achieving the purpose of increasing the emissivity change value and improving the thermal regulation ability.

[0041] (5) Vanadium dioxide (VO2) undergoes a reversible phase transition from a low-temperature insulating state to a high-temperature metallic state at 68°C. The high phase transition temperature limits its practical application. The present invention dopes VO2 with elements such as tungsten, molybdenum, and boron to reduce the phase transition temperature of the smart window device, and by controlling the doping amounts of different elements, smart radiation coatings with different phase transition temperatures can be obtained to meet the energy-saving regulation needs of buildings in different regions.

[0042] In summary, the present invention has the characteristics of intelligent dynamic temperature control, simple structure, convenient large-area preparation, zero energy consumption, etc., which is of great significance for solving the problem of over-refrigeration and alleviating the urban heat island effect. In addition, it also has application potential in the fields of infrared camouflage, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the structure and principle of the dual-band smart window.

[0044] Figure 2 It is the modulation performance of VO2 smart radiation coating in the mid-wave infrared atmospheric window.

[0045] Figure 3 It is the modulation performance of VO2 smart radiation coating in the long-wave infrared atmospheric window.

[0046] 1-resin layer, 2-flaky aluminum powder, 3-X material, 4-VO2 shell layer, 5-base layer. DETAILED DESCRIPTION

[0047] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0048] The embodiment provides a smart radiation coating, comprising a base layer 5 and a resin layer 1 above the base layer 5; the upper surface of the resin layer 1 is uniformly dispersed with horizontally oriented flaky doped VO2(M) core-shell particles Al@X@VO2(M);

[0049] The flaky doped VO2(M) core-shell particle Al@X@VO2(M) has a core material of flaky aluminum powder 2 with a reflectivity greater than 90%, an intermediate layer of X material 3 with an infrared transmittance greater than 95%, and a surface layer of doped VO2 shell 4, wherein the X material 3 is calcium fluoride, zinc sulfide, zinc selenide or barium fluoride.

[0050] Horizontally oriented doped VO2(M) core-shell particles Al@X@VO2(M) are used to achieve the transition between infrared light reflection and absorption properties;

[0051] When the temperature is lower than the phase transition temperature, the transmittance of VO2 is enhanced, and the reflectivity of the flaky aluminum powder reduces the emissivity of the coating. When the temperature is higher than the phase transition temperature, the VO in the doped VO2 (M) core-shell particles x The shell layer transforms into M phase, i.e., metal phase, forming a metal-dielectric-metal "sandwich structure". The incident infrared wave causes a resonant response, resulting in enhanced absorption of the coating and corresponding enhanced emissivity, achieving a cooling effect.

[0052] In some embodiments, the particle size of the flaky aluminum powder 2 is 5 to 15 μm.

[0053] In some embodiments, the shell thickness of the X material 3 is 300nm-1000nm.

[0054] In some embodiments, the VO2 shell layer 4 has a thickness of 20 nm to 60 nm.

[0055] In some embodiments, the VO2 shell layer 4 is doped with tungsten, molybdenum, and boron to reduce its phase transition temperature.

[0056] In some embodiments, the base layer 5 is a copper sheet, a flexible tin foil, a textile fabric, a steel plate or an aluminum alloy plate.

[0057] In some embodiments, a method for preparing doped M-phase VO2 core-shell particles is provided, comprising the following steps:

[0058] Step 1, prepare flaky aluminum powder with a particle size of 5 to 15 μm for later use;

[0059] Step 2: by atomic layer deposition, by controlling the reaction time, coating the flaky aluminum powder with a material X having a thickness of 300 nm to 1000 nm, to obtain flaky Al@X core-shell particles;

[0060] Step 3: Prepare Al@X@VO2 core-shell particles by atomic layer deposition:

[0061] (3.1) Place the Al@X core-shell particles obtained in step 2 into the reaction chamber of the atomic deposition equipment, raise the chamber temperature to the set value, fill with argon gas and maintain a certain pressure, stir the powder by rotating the chamber, and start growing the coating layer by atomic layer deposition ALD:

[0062] (3.2) First, introduce the vanadium source and dopant for a certain period of time, and after they fully react with the –OH on the surface of the Al@X core-shell particle substrate, introduce the carrier gas N2 to remove the byproduct methane generated in this part of the reaction;

[0063] (3.3) Then, water vapor is introduced into the cavity to allow it to fully react with the –CH3 on the surface. Then, carrier gas N2 is introduced again to remove the byproduct CH4. This is one cycle. By setting different numbers of cycles, Al@X@VOx core-shell particles with different shell thicknesses can be obtained.

[0064] Step 4: Prepare Al@X@VO x The particles are calcined in a certain atmosphere to promote VO x The shell layer transforms to the M phase to obtain doped VO2(M) core-shell particles;

[0065] The atmosphere calcination in step 4 is divided into two stages: the first stage is carried out at 550° C. for 2 hours under nitrogen with a purity of 99.99%,

[0066] The second stage is to keep warm at 400-650℃ for 10-30min under the condition of oxygen partial pressure RO2=VO2 / (VO2+VN2)=2.5%~10%.

[0067] In some embodiments, the chamber temperature in step (3.1) is set to 150-200°C;

[0068] In some embodiments, the vanadium source in step (3.2) is triisopropoxyvanadium oxide, and the dopant is ammonium molybdate, sodium tungstate or boric acid.

[0069] In some embodiments, the cycle period in step (3.3) is 400-2000 times.

[0070] In some embodiments, a doped M-phase VO2 core-shell particle is obtained by the preparation method.

[0071] In some embodiments, a method for preparing a smart radiation coating is provided: first, take a certain amount of a compound solvent, add a resin with a solid content of 50% in the compound solvent and stir evenly in a dispersant; secondly, add a certain amount of doped M-phase VO2 core-shell particles Al@X@VO2 obtained by the preparation method of claim 6 or 7 and a certain amount of a floating agent and a dispersant and continue to stir evenly to obtain a spray slurry, wherein the solid content of the doped M-phase VO2 core-shell particles Al@X@VO2 is 20% to 50%; the mass ratio of doped M-phase VO2 core-shell particles: floating agent: dispersant is 5:1:1, and finally the smart radiation coating is obtained by spraying on the base layer.

[0072] In some embodiments, the preparation method of the intelligent radiation coating is as follows: the components of the compound solvent are ethyl acetate: butyl acetate: xylene = 6:3:4 by mass ratio; and / or the resin is acrylic resin, silicone resin, styrene, polyethylene or polystyrene. And / or the floating agent is oleic acid; and / or the dispersant is Hemmings dispersant 904S.

[0073] like Figure 1 As shown, the smart radiation coating proposed by the present invention is mainly composed of Al@X@VO2 core-shell particles, resin adhesive and substrate. First, doped VO2 core-shell particles are obtained by atomic layer deposition-high temperature calcination method; then, the smart coating material with high radiation modulation performance in the infrared band is obtained by spraying. During use, the phase change temperature of VO2 can be adjusted according to different regions, climates and time periods to meet the energy-saving regulation needs of different buildings.

[0074] The performance of the intelligent radiation coating proposed in this invention is analyzed through simulation. Figure 2 and Figure 3The modulation performance of the coating in the infrared light band, where the core material is flaky aluminum powder with a particle size of 10μm, the middle layer is calcium fluoride, the shell thickness is 500nm, the outer layer is VO2 with a thickness of 30nm, and the substrate is stainless steel. As can be seen from the figure, whether in the medium-wave infrared atmospheric window or the far-infrared atmospheric window, the infrared emissivity of the coating increases with the increase of temperature (the emissivity change value is greater than 0.35). At low temperatures, the window can have lower radiation characteristics to achieve heat preservation. As the temperature rises, the emissivity increases, and the corresponding window can dissipate heat through radiation heat dissipation, thereby playing a role in cooling and ultimately achieving the purpose of intelligent temperature control.

[0075] Embodiment 1:

[0076] Preparation of Al@HfO2 core-shell particles:

[0077] Step 1: First, a certain amount of flaky Al powder (15 μm) was placed in the reaction chamber, heated to 80 °C and maintained for 1 h to remove water vapor. After the pretreatment, the chamber temperature was set to the HfO2 formulation growth temperature of 180 °C, and argon was filled and maintained at a pressure of 17.3 Pa (1.3×10 -1 torr) condition, the powder was stirred in a rotating chamber and the coating layer was grown by ALD. Secondly, tetra(ethylmethylamino hafnium), H2O and Ar were used as Hf precursor, oxidant and purge gas, respectively. The feeding and purge time of Hf precursor were fixed at 1.5s and 30s, respectively, and the feeding and purge time of oxidant (H2O) were optimized to 1s and 30s, respectively. Finally, the order of Hf precursor-purge-oxygen source-purge (1.5s-30s-1s-30s) was cycled for 4000 cycles to obtain Al@HfO2 core-shell particles.

[0078] Preparation of doped Al@HfO2@VO2(M) core-shell particles:

[0079] Step 2: Place the Al@HfO2 powder obtained in step 1 into the reaction chamber of the atomic deposition equipment, then raise the chamber temperature by 200°C, fill it with argon and maintain the pressure at 2.5torr, stir the powder by rotating the chamber and start growing the VO2 coating layer using ALD. Tri(isopropoxy)vanadium oxide and water are used as vanadium and oxygen sources, respectively, and nitrogen (N2) is used as the purge gas. During the deposition process, the vanadium source and water are alternately introduced into the chamber in the sequence of vanadium source-N2-H2O-N2 ((1s-8s-0.5s-8s)). When the precursor gas diffuses into the gaps between the particles and reacts, N2 is used to blow out the residual source, and this sequence is repeated for 800 cycles to obtain Al@HfO2@VO x Core-shell particles. Finally, the dried Al@HfO2@VO xThe powder was calcined at 550℃ for 1.5h in a nitrogen atmosphere, at which point the shell VO2 would be reduced to V2O3. A certain proportion of oxygen and nitrogen (oxygen partial pressure of 5%) was then introduced, while the pressure in the vacuum tube furnace was kept constant. After being kept at 500℃ for 30min, the target product Al@HfO2@VO2(M) was obtained.

[0080] Preparation of Al@HfO2@VO2 smart radiation coating:

[0081] First, take a certain amount of compound solvent (prepared according to the mass ratio of ethyl acetate: butyl acetate: xylene = 6:3:4), then add a certain amount of silicone resin (solid content 50%), stir and disperse at a speed of 1300r / min in a disperser for 2h, add a certain amount of Al@HfO2@VO2(M) and stir and disperse at a speed of 1300r / min for 5min to obtain the coating. Then spray the prepared coating on the tinplate, place the sample at room temperature for 4h, and then bake it in an oven at 200℃ for 2h to obtain a sample with a coating thickness of 50-60μm.

[0082] Embodiment 2:

[0083] Preparation of Al@HfO2 core-shell particles:

[0084] Step 1: First, a certain amount of flaky Al powder (15 μm) was placed in the reaction chamber, heated to 80 °C and maintained for 1 h to remove water vapor. After the pretreatment, the chamber temperature was set to the HfO2 formulation growth temperature of 180 °C, and argon was filled and maintained at a pressure of 17.3 Pa (1.3×10 -1 torr) condition, the powder was stirred in a rotating chamber and the coating layer was grown by ALD. Secondly, tetra(ethylmethylamino hafnium), H2O and Ar were used as Hf precursor, oxidant and purge gas, respectively. The feeding and purge time of Hf precursor were fixed at 1.5s and 30s, respectively, and the feeding and purge time of oxidant (H2O) were optimized to 1s and 30s, respectively. Finally, the order of Hf precursor-purge-oxygen source-purge (1.5s-30s-1s-30s) was cycled for 6000 cycles to obtain Al@HfO2 core-shell particles.

[0085] Preparation of doped Al@HfO2@VO2(M) core-shell particles:

[0086] Step 2: Place the Al@HfO2 powder obtained in step 1 into the reaction chamber of the atomic deposition equipment, then raise the chamber temperature by 200°C, fill it with argon and maintain the pressure at 2.5torr, stir the powder by rotating the chamber and start growing the VO2 coating layer using ALD. Tri(isopropoxy)vanadium oxide and water are used as vanadium and oxygen sources, respectively, and nitrogen (N2) is used as the purge gas. During the deposition process, the vanadium source and water are alternately introduced into the chamber in the sequence of vanadium source-N2-H2O-N2 ((1s-8s-0.5s-8s)). When the precursor gas diffuses into the gaps between the particles and reacts, N2 is used to blow out the residual source, and this sequence is repeated for 400 cycles to obtain Al@HfO2@VO x Core-shell particles. Finally, the dried Al@HfO2@VO x The powder was calcined at 550℃ for 1.5h in a nitrogen atmosphere, at which point the shell VO2 would be reduced to V2O3. A certain proportion of oxygen and nitrogen (oxygen partial pressure of 5%) was then introduced, while the pressure in the vacuum tube furnace was kept constant. After being kept at 500℃ for 30min, the target product Al@HfO2@VO2(M) was obtained.

[0087] Preparation of Al@HfO2@VO2 smart radiation coating:

[0088] First, take a certain amount of compound solvent (prepared according to the mass ratio of ethyl acetate: butyl acetate: xylene = 6:3:4), then add a certain amount of silicone resin (solid content 50%), stir and disperse at a speed of 1300r / min in a disperser for 2h, add a certain amount of Al@HfO2@VO2(M) and stir and disperse at a speed of 1300r / min for 5min to obtain the coating. Then spray the prepared coating on the tinplate, place the sample at room temperature for 4h, and then bake it in an oven at 200℃ for 2h to obtain a sample with a coating thickness of 50-60μm.

[0089] Embodiment 3:

[0090] Preparation of Al@HfO2 core-shell particles:

[0091] Step 1: First, a certain amount of flaky Al powder (10 μm) was placed in the reaction chamber, heated to 80 °C and maintained for 1 h to remove water vapor. After the pretreatment, the chamber temperature was set to the HfO2 formula growth temperature of 180 °C, and argon was filled and maintained at a pressure of 17.3 Pa (1.3×10 -1torr) condition, the powder was stirred in a rotating chamber and the coating layer was grown by ALD. Secondly, tetra(ethylmethylamino hafnium), H2O and Ar were used as Hf precursor, oxidant and purge gas, respectively. The feeding and purge time of Hf precursor were fixed at 1.5s and 30s, respectively, and the feeding and purge time of oxidant (H2O) were optimized to 1s and 30s, respectively. Finally, the order of Hf precursor-purge-oxygen source-purge (1.5s-30s-1s-30s) was cycled for 4000 cycles to obtain Al@HfO2 core-shell particles.

[0092] Preparation of doped Al@HfO2@VO2(M) core-shell particles:

[0093] Step 2: Place the Al@HfO2 powder obtained in step 1 into the reaction chamber of the atomic deposition equipment, then raise the chamber temperature by 200°C, fill it with argon and maintain the pressure at 2.5torr, stir the powder by rotating the chamber and start growing the VO2 coating layer using ALD. Tri(isopropoxy)vanadium oxide and water are used as vanadium and oxygen sources, respectively, and nitrogen (N2) is used as the purge gas. During the deposition process, the vanadium source and water are alternately introduced into the chamber in the sequence of vanadium source-N2-H2O-N2 ((2s-8s-1.5s-8s)). When the precursor gas diffuses into the gaps between the particles and reacts, N2 is used to blow out the residual source, and this sequence is repeated for 400 cycles to obtain Al@HfO2@VO x Core-shell particles. Finally, the dried Al@HfO2@VO x The powder was calcined at 550℃ for 1.5h in a nitrogen atmosphere, at which point the shell VO2 would be reduced to V2O3. A certain proportion of oxygen and nitrogen (oxygen partial pressure of 5%) was then introduced, while the pressure in the vacuum tube furnace was kept constant. After being kept at 500℃ for 30min, the target product Al@HfO2@VO2(M) was obtained.

[0094] Preparation of Al@HfO2@VO2 smart radiation coating:

[0095] First, take a certain amount of compound solvent (prepared according to the mass ratio of ethyl acetate: butyl acetate: xylene = 6:3:4), then add a certain amount of silicone resin (solid content 50%), stir and disperse at a speed of 1300r / min in a disperser for 2h, add a certain amount of Al@HfO2@VO2(M) and stir and disperse at a speed of 1300r / min for 5min to obtain the coating. Then spray the prepared coating on the tinplate, place the sample at room temperature for 4h, and then bake it in an oven at 200℃ for 2h to obtain a sample with a coating thickness of 50-60μm.

[0096] Embodiment 4:

[0097] Preparation of Al@HfO2 core-shell particles:

[0098] Step 1: First, a certain amount of flaky Al powder (15 μm) was placed in the reaction chamber, heated to 80 °C and maintained for 1 h to remove water vapor. After the pretreatment, the chamber temperature was set to the HfO2 formulation growth temperature of 180 °C, and argon was filled and maintained at a pressure of 17.3 Pa (1.3×10 -1 torr) condition, the powder was stirred in a rotating chamber and the coating layer was grown by ALD. Secondly, tetra(ethylmethylamino hafnium), H2O and Ar were used as Hf precursor, oxidant and purge gas, respectively. The feeding and purge time of Hf precursor were fixed at 1.5s and 30s, respectively, and the feeding and purge time of oxidant (H2O) were optimized to 1s and 30s, respectively. Finally, the order of Hf precursor-purge-oxygen source-purge (1.5s-30s-1s-30s) was cycled for 4000 cycles to obtain Al@HfO2 core-shell particles.

[0099] Preparation of doped Al@HfO2@VO2(M) core-shell particles:

[0100] Step 2: Place the Al@HfO2 powder obtained in step 1 into the reaction chamber of the atomic deposition equipment, then raise the chamber temperature by 200°C, fill it with argon and maintain the pressure at 2.5torr, stir the powder by rotating the chamber and start growing the VO2 coating layer using ALD. Tri(isopropoxy)vanadium oxide and water are used as vanadium and oxygen sources, respectively, and nitrogen (N2) is used as the purge gas. During the deposition process, the vanadium source and water are alternately introduced into the chamber in the sequence of vanadium source-N2-H2O-N2 ((1s-8s-0.5s-8s)). When the precursor gas diffuses into the gaps between the particles and reacts, N2 is used to blow out the residual source, and this sequence is repeated for 800 cycles to obtain Al@HfO2@VO x Core-shell particles. Finally, the dried Al@HfO2@VO x The powder was calcined at 550℃ for 1.5h in a nitrogen atmosphere, at which point the shell VO2 would be reduced to V2O3. A certain proportion of oxygen and nitrogen (oxygen partial pressure of 5%) was then introduced, while the pressure in the vacuum tube furnace was kept constant. After being kept at 500℃ for 30min, the target product Al@HfO2@VO2(M) was obtained.

[0101] Preparation of Al@HfO2@VO2 smart radiation coating:

[0102] First, take a certain amount of compound solvent (prepared according to the mass ratio of ethyl acetate: butyl acetate: xylene = 6:3:4), then add a certain amount of silicone resin (solid content 50%), stir and disperse at a speed of 1300r / min in a disperser for 2h, add a certain amount of Al@HfO2@VO2(M), Hemmings dispersant 904S and oleic acid, stir and disperse at a speed of 1300r / min for 5min to obtain the coating. Then spray the prepared coating on the textile fiber cloth, place the sample at room temperature for 4h, and then bake it in an oven at 200℃ for 2h to obtain a sample with a coating thickness of 20-30μm.

[0103] Embodiment 5:

[0104] Preparation of Al@HfO2 core-shell particles:

[0105] Step 1: First, a certain amount of flaky Al powder (15 μm) was placed in the reaction chamber, heated to 80 °C and maintained for 1 h to remove water vapor. After the pretreatment, the chamber temperature was set to the HfO2 formulation growth temperature of 180 °C, and argon was filled and maintained at a pressure of 17.3 Pa (1.3×10 -1 torr) condition, the powder was stirred in a rotating chamber and the coating layer was grown by ALD. Secondly, tetra(ethylmethylamino hafnium), H2O and Ar were used as Hf precursor, oxidant and purge gas, respectively. The feeding and purge time of Hf precursor were fixed at 1.5s and 30s, respectively, and the feeding and purge time of oxidant (H2O) were optimized to 1s and 30s, respectively. Finally, the order of Hf precursor-purge-oxygen source-purge (1.5s-30s-1s-30s) was cycled for 4000 cycles to obtain Al@HfO2 core-shell particles.

[0106] Doped Al@HfO2@V 1-y Mo y O x (M) Preparation of core-shell particles:

[0107] Step 2: Place the Al@HfO2 powder obtained in step 1 into the reaction chamber of the atomic deposition equipment, then raise the chamber temperature by 200°C, fill with argon and maintain the pressure at 2.5torr, stir the powder by rotating the chamber and start growing the VO2 coating layer using ALD. Tri(isopropoxy)vanadium oxide and water are used as vanadium and oxygen sources, respectively, ammonium molybdate is used as a dopant, and nitrogen (N2) is used as a purge gas. During the deposition process, the vanadium source and water are alternately introduced into the chamber in the sequence of vanadium source (dopant)-N2-H2O-N2 ((1s-8s-0.5s-8s)). When the precursor gas diffuses into the gaps between the particles and reacts, N2 is used to blow out the residual source, and this sequence is repeated for 800 cycles to obtain Al@HfO2@V1-y Mo y O x Core-shell particles. Finally, the dried Al@HfO2@V 1-y Mo y O x The powder was calcined at 550℃ for 1.5h in a nitrogen atmosphere. At this time, the shell VO2 was reduced to V2O3. A certain proportion of oxygen and nitrogen (oxygen partial pressure was 5%) was introduced, and the pressure in the vacuum tube furnace was kept constant. After 500℃ for 30min, Al@HfO2@V 1-y Mo y O2 target product.

[0108] Al@HfO2@V 1-y Mo y Preparation of O2 smart radiation coating:

[0109] First, take a certain amount of compound solvent (prepared according to the mass ratio of ethyl acetate: butyl acetate: xylene = 6:3:4), then add a certain amount of silicone resin (solid content 50%), stir and disperse in a disperser at a speed of 1300r / min for 2h, add a certain amount of Al@HfO2@V 1-y Mo y O2, Hemmings dispersant 904S and oleic acid were stirred and dispersed at a speed of 1300r / min for 5 minutes to obtain the coating. The prepared coating was then sprayed on the textile fiber cloth, the sample was placed at room temperature for 4 hours, and then placed in an oven at 200°C for 2 hours to obtain a sample with a coating thickness of 20-30μm.

[0110] Embodiment 6:

[0111] Preparation of Al@HfO2 core-shell particles:

[0112] Step 1: First, a certain amount of flaky Al powder (15 μm) was placed in the reaction chamber, heated to 80 °C and maintained for 1 h to remove water vapor. After the pretreatment, the chamber temperature was set to the HfO2 formulation growth temperature of 180 °C, and argon was filled and maintained at a pressure of 17.3 Pa (1.3×10 -1 torr) condition, the powder was stirred in a rotating chamber and the coating layer was grown by ALD. Secondly, tetra(ethylmethylamino hafnium), H2O and Ar were used as Hf precursor, oxidant and purge gas, respectively. The feeding and purge time of Hf precursor were fixed at 1.5s and 30s, respectively, and the feeding and purge time of oxidant (H2O) were optimized to 1s and 30s, respectively. Finally, the order of Hf precursor-purge-oxygen source-purge (1.5s-30s-1s-30s) was cycled for 4000 cycles to obtain Al@HfO2 core-shell particles.

[0113] Doped Al@HfO2@V 1-y W y Preparation of O2(M) core-shell particles:

[0114] Step 2: Place the Al@HfO2 powder obtained in step 1 into the reaction chamber of the atomic deposition equipment, then raise the chamber temperature by 200°C, fill with argon and maintain the pressure at 2.5torr, stir the powder by rotating the chamber and start growing the VO2 coating layer using ALD. Tri(isopropoxy)vanadium oxide and water are used as vanadium and oxygen sources, respectively, ammonium tungstate is used as a dopant, and nitrogen (N2) is used as a purge gas. During the deposition process, the vanadium source and water are alternately introduced into the chamber in the sequence of vanadium source (dopant)-N2-H2O-N2 ((1s-8s-0.5s-8s)). When the precursor gas diffuses into the gaps between the particles and reacts, N2 is used to blow out the residual source, and this sequence is repeated for 800 cycles to obtain Al@HfO2@V 1-y W y O x Core-shell particles. Finally, the dried Al@HfO2@V 1-y W y O x The powder was calcined at 600℃ for 1.5h in a nitrogen atmosphere, at which point the shell VO2 would be reduced to V2O3. A certain proportion of oxygen and nitrogen (oxygen partial pressure was 10%) was introduced, and the pressure in the vacuum tube furnace was kept constant. After being kept at 500℃ for 30min, Al@HfO2@V 1-y W y O2 target product.

[0115] Al@HfO2@V 1-y W y Preparation of O2 smart radiation coating:

[0116] First, take a certain amount of compound solvent (prepared according to the mass ratio of ethyl acetate: butyl acetate: xylene = 6:3:4), then add a certain amount of silicone resin (solid content 50%), stir and disperse in a disperser at a speed of 1300r / min for 2h, add a certain amount of Al@HfO2@V 1-y W y O2, Hemmings dispersant 904S and oleic acid were stirred and dispersed at a speed of 1300r / min for 5 minutes to obtain the coating. The prepared coating was then sprayed on a textile fiber cloth, the sample was placed at room temperature for 4 hours, and then placed in an oven at 200°C for 2 hours to obtain a sample with a coating thickness of 30-40μm.

[0117] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A smart radiation coating, characterized in that: It comprises a base layer (5) and a resin layer (1) above the base layer (5); the upper surface of the resin layer (1) is uniformly dispersed with horizontally oriented flaky doped VO2(M) core-shell particles Al@X@VO2(M); The flaky doped VO2(M) core-shell particle Al@X@VO2(M) comprises a core material of flaky aluminum powder (2) with a reflectivity greater than 90%, an intermediate layer of X material (3) with an infrared transmittance greater than 95%, and a surface layer of a doped VO2 shell layer (4), wherein the X material (3) is calcium fluoride, zinc sulfide, zinc selenide or barium fluoride. Horizontally oriented doped VO2(M) core-shell particles Al@X@VO2(M) are used to achieve the transition between infrared light reflection and absorption properties; When the temperature is lower than the phase transition temperature, the permeability of VO2 is enhanced, and the reflectivity of the flaky aluminum powder reduces the emissivity of the coating. When the temperature is higher than the phase transition temperature, the VO in the doped VO2 (M) core-shell particles x The shell layer transforms into M phase, i.e., metal phase, forming a metal-dielectric-metal "sandwich structure". The incident infrared wave causes a resonant response, resulting in enhanced absorption of the coating and corresponding enhanced emissivity, achieving a cooling effect.

2. The smart radiation coating according to claim 1, characterized in that: The particle size of the flaky aluminum powder (2) is 5 to 15 μm; And / or the shell thickness of the X material (3) is 300nm-1000nm.

3. The smart radiation coating according to claim 1, characterized in that: The thickness of the VO2 shell layer (4) is 20nm-60nm.

4. The smart radiation coating according to claim 1, characterized in that: The VO2 shell layer (4) is doped with tungsten, molybdenum and boron elements to reduce its phase transition temperature.

5. The smart radiation coating according to claim 1, characterized in that: The base layer (5) is a copper sheet, a flexible tin foil, a textile cloth, a steel plate or an aluminum alloy plate.

6. A method for preparing doped M-phase VO2 core-shell particles, characterized in that The following steps are involved: Step 1, prepare flaky aluminum powder with a particle size of 5 to 15 μm for later use; Step 2: by atomic layer deposition, by controlling the reaction time, coating the flaky aluminum powder with a material X having a thickness of 300 nm to 1000 nm, to obtain flaky Al@X core-shell particles; Step 3: Prepare Al@X@VO2 core-shell particles by atomic layer deposition: (3.1) Place the Al@X core-shell particles obtained in step 2 into the reaction chamber of the atomic deposition equipment, raise the chamber temperature to the set value, fill with argon gas and maintain a certain pressure, stir the powder by rotating the chamber, and start growing the coating layer by atomic layer deposition ALD: (3.2) First, introduce the vanadium source and dopant for a certain period of time. After the vanadium source and dopant react fully with the –OH on the surface of the Al@X core-shell particle substrate, introduce the carrier gas N2 to remove the byproduct methane generated in this part of the reaction. (3.3) Then, water vapor is introduced into the cavity to fully react with the –CH3 on the surface; then, carrier gas N2 is introduced again to remove the byproduct CH4; this is one cycle, and Al@X@VOx core-shell particles with different shell thicknesses can be obtained by setting different numbers of cycles; Step 4: Prepare Al@X@VO x The particles are calcined in a certain atmosphere to promote VO x The shell layer transforms to the M phase to obtain doped VO2(M) core-shell particles; The atmosphere calcination in step 4 is divided into two stages: the first stage is carried out at 550° C. for 2 hours under nitrogen with a purity of 99.99%, The second stage is to keep warm at 400-650℃ for 10-30min under the condition of oxygen partial pressure RO2=VO2 / (VO2+VN2)=2.5%~10%.

7. The method for preparing doped M-phase VO2 core-shell particles according to claim 6, characterized in that: The chamber temperature in step (3.1) is set to 150-200°C; And / or in step (3.2), the vanadium source is triisopropoxy vanadium oxide, and the dopant is ammonium molybdate, sodium tungstate or boric acid; And / or the cycle period in step (3.3) is 400-2000 times.

8. A doped M-phase VO2 core-shell particle, characterized in that The method is obtained by the preparation method according to claim 6 or 7.

9. A method for preparing an intelligent radiation coating, characterized in that: First, take a certain amount of compound solvent, add a resin with a solid content of 50% in the compound solvent and stir evenly in a dispersant; secondly, add a certain amount of doped M-phase VO2 core-shell particles Al@X@VO2 obtained by the preparation method of claim 6 or 7 and a certain amount of floating agent and dispersant and continue to stir evenly to obtain a spray slurry, wherein the solid content of the doped M-phase VO2 core-shell particles Al@X@VO2 is 20% to 50%; the mass ratio of doped M-phase VO2 core-shell particles: floating agent: dispersant is 5:1:1, and finally the smart radiation coating is obtained by spraying on the substrate.

10. The method for preparing the smart radiation coating according to claim 9, characterized in that: The components of the composite solvent are ethyl acetate:butyl acetate:xylene=6:3:4 in terms of mass ratio; and / or the resin is acrylic resin, silicone resin, styrene, polyethylene or polystyrene; And / or the floating agent is oleic acid; And / or the dispersant is Hemmings dispersant 904S.

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