Preparation and application of rare earth nickelate electronic phase change oxide curved surface coating composite materials

Abstract

The present invention provides a method for preparing and applying a composite material based on a rare earth nickelate electronic phase change oxide curved surface coating. The main concept is to design rare earth nickelate and core materials in combination with application scenarios, and utilize the chemical adsorption of rare earth nickelate to nucleate and grow a polycrystalline coating on the surface of the curved core material, thereby achieving the coupled application of the electronic phase change properties of rare earth nickelate and the functional properties of the core material. The advantages of this method are that it can achieve adsorption and coating of rare earth nickelate on the surface of core materials with a micron-scale curvature radius, and can design complex devices based on the application scenario and the electronic phase change properties. The metal-insulator transition properties of the prepared composite material and the functional properties of the core material can achieve multi-dimensional functional response under external field design and control, and can be applied to intelligent electromagnetic shielding, optical design and infrared camouflage, optical anti-counterfeiting, external field sensitive resistors, logic electronic devices, and catalysis.

Description

Technical Field

[0001] The present invention belongs to the field of functional composite materials, and specifically relates to the preparation and application of rare earth nickelate electronic phase change oxide curved surface coating composite materials. Rare earth nickelate forms a coating polycrystalline layer by surface adsorption of a curved core with different crystal structures and no lattice matching relationship. The morphology of the curved core material can be determined by its properties and application scenarios. The surface is modified by a polycrystalline rare earth nickelate with reversible electronic phase change properties, thereby obtaining a composite material with both electronic phase change functional properties and shape adjustable properties. The technology provided by the present invention has potential application value in intelligent electromagnetic shielding, optical design and infrared camouflage, optical anti-counterfeiting, external field sensitive resistors, logic electronic devices, and catalysis. Background Art

[0002] Rare earth nickelate oxides have complex electronic and magnetic structures and exhibit metal-insulator phase transition characteristics triggered by characteristic temperature. Its material system mainly includes: 1) 113-type perovskite ReNiO3, where Re is a rare earth element other than La; 2) layered perovskite structure A n+1 Ni n O 3n+1 (n=1, 2, 3), A is a rare earth element or a mixture of rare earth and alkaline earth elements.

[0003] Among them, ReNiO3 has a rich electronic structure. Under the triggering of characteristic temperature, characteristic pressure, polarization electric field, chemical or electrochemical hydrogenation, multiple electronic phase transitions can occur and cause sudden changes in the physical properties of the material, such as resistivity, dielectric constant and infrared reflectivity [1-3]. ReNiO3 characteristic trigger temperature (T MIT ) can be continuously regulated in a wide temperature range of 100-600K by using rare earth element components. By using this characteristic, the conductivity of the material can be regulated by temperature changes, thereby regulating the reflection of electromagnetic waves on the surface of the material [4], and obtaining an electromagnetic shielding material that can be intelligently regulated in multiple dimensions. When the temperature rises above the T MIT Transformed into the metal phase, the electrical conductivity of the material is improved, the reflection and shielding efficiency of electromagnetic waves is improved, and the external field intelligent triggering of the electromagnetic shielding function is realized. The temperature does not exceed T MIT , rare earth nickelates are insulator phases, and electromagnetic waves can penetrate the material [5]. At the same time, the optical properties of rare earth nickelates before and after phase transition can be used to design near-infrared intelligent detection and positioning and intelligent sensing temperature adaptive devices [6-9]. Alternatively, the anodic catalytic oxidation properties of rare earth nickelates can be used for sewage treatment. The active oxygen physically adsorbed on the anode surface oxidizes the pollutants and eventually degrades them into substances with low biotoxicity or easily biodegradable substances. Therefore, ReNiO3 has potential application value in intelligent electromagnetic shielding, optical design and infrared camouflage, optical anti-counterfeiting, external field sensitive resistors, logic electronic devices, and catalysis. [10-12].

[0004] Rare earth nickel-based layered perovskites Re2NiO4 and Re3Ni2O7 both exhibit metal-insulator transition characteristics above room temperature, and their resistivity will first decrease and then increase with increasing temperature. For La3Ni2O7, as the temperature increases, the semiconductor properties gradually transform into metallic properties, and its phase transition temperature is around 300 degrees Celsius

[13] . In addition, the rare earth nickel-based layered perovskite oxide La3Ni2O7 exhibits high-temperature superconductivity of 80K under a pressure of 14GPa, which provides help for further research on the high-temperature superconductivity mechanism

[14] . And as the rare earth ion radius decreases, the phase transition temperature of Re2NiO4 will gradually increase. As for Re4Ni3O 10 , then as the temperature rises, it shows a transition from low temperature metal phase to high temperature metal phase. 10 At a pressure of 43 GPa, low-temperature zero resistance appears at 20 K, indicating a superconducting state. As the pressure increases, the superconducting transition temperature increases further, and at 65 GPa, the superconducting transition temperature increases to 30 K

[15] . By doping its rare earth sites with other rare earth elements or alkaline earth metal elements, the Re of rare earth nickel-based perovskite can be regulated. n+1 Ni n O 3n+1 (n=1, 2, 3) metal-insulator phase transition characteristics. In addition, other transition metal elements can be added to the nickel position to further control the Re of rare earth nickel-based perovskite. n+1 Ni n O 3n+1 (n=1, 2, 3) electrical properties. In addition to the electrical applications of rare earth nickel-based perovskites Re2NiO4 and Re3Ni2O7 similar to 113 structure nickelates, Re3Ni2O7 and Re4Ni3O 10 When the rare earth element is lanthanum, it has high-temperature superconducting properties under pressure, and has broad application prospects in the fields of energy, medicine, information, etc.

[0005] However, due to the brittleness and high hardness of rare earth nickel-based oxides, many current applications of rare earth nickelate materials rely on two-dimensional growth on planar substrates, and cannot achieve the encapsulation of rare earth nickelate on existing curved cores. On the one hand, most rare earth nickelate materials are in a thermodynamically metastable phase, making it difficult to nucleate and grow on substrates that lack a coherent relationship. On the other hand, when a curved substrate and the rare earth nickelate are coherent, the lattice distortion energy caused by the curvature radius of the substrate further increases the material's forward Gibbs free synthesis energy, thereby hindering nucleation and growth. In summary, achieving the growth of rare earth nickelate materials on curved substrates, thereby preparing rare earth nickelate curved surface encapsulated composite materials, has enormous application value.

[0006] 【1】Escote M T,Da Silva A M L,Matos J D R,et al.General properties ofpolycrystal l ine LnNiO3(Ln=Pr,Nd,Sm)compounds prepared through differentprecursors[J].Journal of Solid State Chemistry,2000,151(2):298-307.

[0007] 【2】Aydogdu G H,Ha SD,Viswanath B,et al.Epitaxy,strain,and compositioneffects on metal-insulator transition characteristics of SmNiO3 thin films[J].Journal of Applied Physics,2011,109(12):124110.

[0008] 【3】Kumar Y,Pratap Singh A,Sharma S K,et al.Irradiation inducedmodification in transport properties of LaNiO3 thin films:An x-ray absorptionstudy[J].Applied Physics Letters,2012,101(11):112103.

[0009] 【4】Bhattacharjee,Y.;Chatterjee,D.;Bose,S.Core–multishellheterostructure with excellent heat dissipation for electromagneticinterference shielding.ACS Appl.Mater.Interfaces 2018,10(36),30762–30773

[0010] 【5】Bhattacharjee Y,Bose S.Core-shell nanomaterials for microwaveabsorption and electromagnetic interference shielding:a review[J].Acs AppliedNano Materials,2021,4(2):949-972.

[0011] 【6】BESL P J,JAIN R C.Three-dimensional object recognition[J].ACMComputing Sur veys1985,17(1):75-145.

[0012] 【7】CHAI Y.In-sensor computing for machine vision[J].Nature,2020,579(7797):32-33.

[0013] 【8】AFSHARI H,JACQUES L,BAGNATO L,et al.The PANOPTIC camera:a plenoptic sensor with real-time omnidirectional capability[J].Journal of SignalProcessing Systems for Signal Image and Video Technology,2013,70(3):305-328.

[0014] 【9】SONG Y M,XIE Y,MALYARCHUK V,et al.Digital cameras with designsinspired by the arthropod eye[J].Nature,2013,497(7447):95-99.

[0015]

[10] Schwanz D,Zhang Z,Narayanan B,et al.Perovskite nickelates aselectric-field sensors in salt water[J].Nature,2018,553(7686):68-72.

[0016]

[11] Zhang HT, Zuo F, Li F, et al.Perovskite nickelates as bio-electronic interfaces[J].Nature Communications, 2019,10(1):1-7.

[0017]

[12] Zhang HT, Park TJ, Zaluzhnyy IA, et al. Perovskite neural trees[J]. Nature Communications, 2020, 11(1):1-9.

[0018]

[13] Sun H, Huo M, Hu X, et al. Signatures of superconductivity near 80Kin a nickelate under high pressure. Nature 621,493–498(2023).

[0019]

[14] G.Wang, N.Wang, J.Hou, L.Ma, et al. Pressure induced superconductivity in polycrystalline La3Ni2O 7. Physical Review X 14,011040(2024)

[0020]

[15] Zhu Y, Peng D, Zhang E, et al.Superconductivity in pressurizedtrilayer La4Ni3O 10-δ single crystals.Nature 631,531–536(2024). Summary of the Invention

[0021] This invention provides a method for preparing and applying a composite material based on a rare earth nickelate-based electronic phase-change oxide surface coating. The key concept is to design the rare earth nickelate and core material based on the application scenario, and utilize the rare earth nickelate chemical adsorption to nucleate and grow a polycrystalline coating on the surface of the curved core material, thereby achieving a coupled application of the rare earth nickelate's electronic phase-change properties and the core material's functional properties. The technology provided by this invention enables the prepared composite material's metal-insulator transition properties and the core material's functional properties to achieve multi-dimensional functional responses under external field design and control. The technology has applications in intelligent electromagnetic shielding, optical design and camouflage, field-sensitive resistors, logic electronic devices, and catalysis.

[0022] A method for preparing a rare earth nickelate electronic phase change oxide curved surface coated composite material, characterized in that the preparation of the composite material with the rare earth nickelate coated core comprises the following steps:

[0023] 1) Design the material composition, electronic phase transition properties, and synergistic mode of the rare earth nickelate with the core material according to the application scenario. Select the core material composition, surface shape and curvature, and size. Improve its surface chemical adsorption of the rare earth nickelate in the thermodynamically metastable phase in molten salt through surface modification.

[0024] 2) According to the stoichiometric ratio of the metal elements in the selected rare earth nickelate oxide, weigh the corresponding nickel and rare earth element precursor powders, add a certain proportion of molten salt and mix them evenly, and apply the prepared mixed powder to the outside of the core material in step 1) or place the core material in the mixed powder and compact it;

[0025] 3) Heating in a strong oxidizing atmosphere allows the precursor powder to be evenly mixed in the molten salt, and reducing the original positive Gibbs free energy of the rare earth nickelate through chemical adsorption on the surface of the core material, thereby nucleating and growing a rare earth nickelate polycrystalline coating layer on the surface of the core material. After cooling, the prepared composite material consisting of the rare earth nickelate polycrystalline layer coating the core material is taken out and washed with a solvent to remove residual flux.

[0026] Furthermore, the core material components include aluminum oxide, titanium oxide, zirconium oxide, hafnium oxide, and garnet ferrite, and its morphology includes single crystal and polycrystalline ceramic body, and its curved surface shape includes sphere, ellipsoid, and cylinder, and its typical size range is 1 micron to 1 centimeter. The core material is characterized in that its surface has an adsorption effect on rare earth and nickel element precursors in molten salt, and is different from the crystal structure of rare earth nickelate and has no lattice matching relationship; the surface chemical environment of the above-mentioned core material can be modified by acid washing, alkali washing, heating in atmosphere, and surface doping process to improve the adsorption effect of the surface of rare earth nickelate, thereby promoting the rare earth nickelate in a thermodynamically metastable phase to form a coating layer in a polycrystalline form on the surface of the core material with a small curvature radius.

[0027] Furthermore, the functional properties of the core material can be functionally designed or hollowed out to fill in a functional material body, thereby coordinating the functional properties of the rare earth nickelate coating layer; the core material functions include: high infrared emissivity, microwave absorption, electromagnetic induction, ferroelectricity, and high dielectric properties; the composite of the rare earth nickelate coating layer and the core functional properties mainly includes two methods: 1) using an external field to trigger the metal-insulator phase change properties of the rare earth nickelate coating layer to achieve reversible shielding of the core function; 2) triggering the reversible triggering of the metal-insulator phase change of the rare earth nickelate coating layer through the coupling of the core layer and the external field, thereby achieving a sudden change in the properties of the nickelate-coated core composite material. The external field forms of the electronic phase change properties of the rare earth nickelate coating layer include: ambient temperature, polarization electric field, chemical environment, stress, alternating electric field, and alternating magnetic field. By adjusting the composition, curvature radius, thickness of the rare earth nickelate coating layer and the composite design with the core material, the threshold range of the external field triggering the electronic phase change can be controlled; in a preferred embodiment, polycrystalline neodymium samarium nickelate (Nd 0.4 Sm 0.6NiO3) coated with yttrium iron garnet ferrite spheres with a diameter of 1 mm, by changing the external microwave power to change the temperature of the ferrite spheres to trigger the nickelate metal insulator transition, thereby realizing the external field intelligent triggering of the electromagnetic shielding switch effect; in another preferred embodiment, a Zr-doped alumina sphere with a diameter of 1 mm coated with polycrystalline samarium nickelate (SmNiO3) has an increased transmittance of the coating layer to infrared light and a decreased emissivity when the temperature is low. When the temperature exceeds the phase transition temperature, the samarium nickelate is in a metallic phase, the emissivity increases, and the transmittance decreases, and can be applied to 8-14 μm infrared camouflage in the temperature range of 100-140°C; in another preferred embodiment, a Zr-doped alumina sphere with a diameter of 1 mm coated with polycrystalline praseodymium nickelate (PrNiO3) has an increased transmittance of the coating layer to infrared light and a decreased emissivity when the temperature exceeds the phase transition temperature. The 1 mm yttrium iron garnet ferrite ball has an electromagnetic shielding performance of the polycrystalline layer controlled by temperature, thereby controlling the resonant frequency of the yttrium iron garnet single crystal ball resonator in a variable external magnetic field, which can be used for electronic countermeasures, electronic interference and anti-interference equipment; in another preferred embodiment, alumina balls with a diameter of 10 microns coated with polycrystalline samarium nickelate (SmNiO3) are arranged and dispersed in an organic polymer with dielectric properties, and the organic polymer is solidified to form a polymer / composite ball layer with a thickness of about 50 microns, which is composited between dielectric layers, and an electric field is applied to the electrode to form a polarization electric field between the layers to trigger the metal-insulator phase transition of the composite ball, thereby realizing a sudden drop in resistivity, thereby achieving a breakdown effect. In another preferred embodiment, 30-micron-diameter alumina spheres coated with polycrystalline neodymium nickelate (NdNiO3) are dispersed in a conductive organic polymer. The organic polymer is solidified to form a polymer / composite sphere layer approximately 150 microns thick, which is then composited between dielectric layers. Stress is applied to the electrodes to trigger a metal-insulator phase transition in the interlayer composite spheres, achieving a sudden drop in resistivity. In another preferred embodiment, 100-micron-diameter alumina composite spheres filled with magnetic particles coated with polycrystalline neodymium nickelate (NdNiO3) are fabricated. The principle that magnetic particles generate heat due to eddy currents and hysteresis in an alternating magnetic field is utilized to raise the core temperature to the NdNiO3 phase transition temperature, thereby triggering the outer layer's metal-insulator transition. This achieves the coupling of the alternating magnetic field with the core functional body to trigger the rare earth nickelate electronic phase transition.

[0028] Furthermore, the crystal structure of the rare earth nickelate includes 113 type perovskite ReNiO3 and layered perovskite Re n+1 Ni n O 3n+1 ; For ReNiO3, its rare earth element Re sites include: praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), yttrium (Y) and the common occupation of the above elements in different proportions; For the layered perovskite structure Re n+1 Ni n O 3n+1, which mainly includes Re2NiO4, Re3Ni2O7, Re4Ni3O corresponding to n = 1, 2, 3 10 , the rare earth element Re site of which includes: lanthanum (La), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), yttrium (Y) and the co-occupation of different proportions of the above elements; by changing the rare earth elements, the regulation of the electronic energy band structure, metal-insulator phase transition characteristics, and hydrogen-induced electronic phase transition characteristics of rare earth nickelates can be achieved; in a preferred example, polycrystalline neodymium samarium nickelate (Sm x Nd 1-x NiO3) (0 < x < 1) coated alumina spheres with a diameter of 500 microns achieved continuous regulation of the phase transition temperature within the range of 200 - 400 K. As the Sm content increased, the phase transition temperature increased linearly, and among which the phase transition temperature of Nd 0.4 Sm 0.6 NiO3 was close to room temperature; in another preferred example, compared with the ceramic fiber with a curved surface radius of 10 microns coated with neodymium nickelate (NdNiO3), the change in resistivity before and after hydrogenation of the ceramic fiber coated with polycrystalline europium nickelate (EuNiO3) increased by 3 orders of magnitude; in another preferred example, compared with the alumina spheres with a diameter of 600 microns coated with polycrystalline double perovskite structure lanthanum nickelate (La 2.7 Pr 0.3 Ni2O7), the resistivity showed an upward trend for the alumina spheres with a diameter of 600 microns coated with polycrystalline double perovskite structure praseodymium-doped lanthanum nickelate (La

[0029] Furthermore, the rare earth site of the above perovskite and layered perovskite can be partially replaced by alkaline earth element Ae, or the Ni-site can be partially replaced by other transition elements, so as to further regulate the valence state of nickel element, the electronic structure, electrical transport properties, and magnetism of the rare earth nickelate coating layer; among which, the alkaline earth element Ae includes calcium, strontium, and barium; Re 2-x Ae x NiO4, Re 3-x Ae x Ni2O7, Re 4-x Ae x Ni3O 10 the substitution range of alkaline earth elements is 0 < x ≤ 1 for all, and Re 1-x Ae x NiO3 the substitution range of alkaline earth elements is 0 < x ≤ 0.3 for all; the other transition elements are preferably manganese, iron, rhenium, vanadium, and cobalt, and their substitution range for Ni-elements is greater than 0 and less than or equal to 30%; in a preferred example, polycrystalline double perovskite structure manganese-doped lanthanum nickelate (La3Mn 0.2 Ni1.8 The resistivity of the 300 μm diameter alumina sphere coated with polycrystalline double-layer perovskite structure lanthanum nickelate (La3Ni2O7) is significantly increased compared to the 300 μm diameter alumina sphere coated with polycrystalline double-layer perovskite structure lanthanum nickelate (La3Ni2O7). In another preferred embodiment, the resistivity of the 300 μm diameter alumina sphere coated with polycrystalline single-layer perovskite structure cobalt-doped lanthanum nickelate (La2Co 0.1 Ni 0.9 O4) coated with a 300 micron diameter alumina ball, the resistivity is significantly increased compared to the 300 micron diameter alumina ball coated with a polycrystalline single-layer perovskite structure lanthanum nickelate (La2NiO4); in another preferred embodiment, the polycrystalline three-layer perovskite structure iron-doped lanthanum nickelate (La4Fe 0.3 Ni 2.7 O 10 ) coated with alumina beads with a diameter of 300 microns compared to polycrystalline three-layer perovskite structure lanthanum nickelate (La4Ni3O 10 ) coated with 300 μm diameter alumina spheres, the resistivity is increased; in another preferred embodiment, the resistivity of 600 μm diameter alumina spheres coated with polycrystalline single-layer perovskite structure strontium-doped lanthanum nickelate (LaSrNiO4) is higher than that of 600 μm diameter alumina spheres coated with polycrystalline single-layer perovskite structure strontium-doped praseodymium nickelate (PrSrNiO4), which is an order of magnitude higher;

[0030] Furthermore, the nickel and rare earth element precursor powders include nickel oxides, nitrates, acetates and carbonates, and rare earth element oxides, nitrates, acetates and carbonates. The specific molten salts include: potassium chloride (KCl), sodium chloride (NaCl), lithium chloride (LiCl), potassium carbonate (K2CO3), sodium carbonate (Na2CO3) or their mixtures. The type and mixing ratio of the flux can be used to control the melting point of the flux and further design the reaction temperature. The ratio of the precursor to the molten salt ranges from 0.05 to 50, and the applied oxygen pressure ranges from 0.1 MPa to 100 MPa. By designing the molten salt composition, coordinating the reaction temperature and oxygen pressure, the adsorption energy of the curved core in the molten salt on the rare earth nickelate precursor can be effectively controlled, thereby further controlling the crystallization quality, grain size, surface morphology of the polycrystalline coating layer, and the curvature radius of the curved core that can be wrapped. In a preferred embodiment, for an alumina ball coated with polycrystalline neodymium nickelate (NdNiO3), when the radius of curvature of the alumina ball is 1 mm, potassium chloride is used as the molten salt, and the polycrystalline layer can be coated on the ball at 800 degrees Celsius and 7 MPa oxygen pressure, and the grains of the polycrystalline layer have regular shapes and uniform sizes; when the radius of curvature of the alumina ball is 10 μm, in order to enable the polycrystalline layer to coat a smaller core ball, considering improving its surface adsorption, the molten salt is adjusted to a mass fraction of potassium chloride and lithium chloride of 1:1, and the temperature and oxygen pressure are appropriately increased. Finally, the curved surface coating is achieved at 1000 degrees Celsius and 10 MPa oxygen pressure. The grains of the polycrystalline layer are more irregular in shape than those adsorbed by the 1 mm ball.

[0031] Furthermore, the prepared rare earth nickelate curved surface coated core composite material can be further arranged into an array, and the overall optical properties, microwave transmission properties, and DC and AC transport properties before and after the electronic phase transition can be adjusted by regulating the array arrangement mode; in a preferred embodiment, the polycrystalline samarium neodymium nickelate (Nd 0.25 Sm 0.75 A high-precision, large-area multilayer array of 500-micron-diameter alumina spheres coated with NiO3) has a modulation effect on microwaves in the infrared-terahertz band, and the reflection and transmission frequencies can be controlled by the radius of the sphere surface and the composition and thickness of the rare earth nickelate coating layer; in another preferred embodiment, a polycrystalline neodymium nickelate (Pr 0.5 Nd 0.5 Alumina spheres with a diameter of 1 mm coated with NiO3 are arranged into a bionic compound eye-like hemisphere. The process is to receive and sense the infrared signals of the surrounding environment and send them to the sensor. The array and detector signal readout and some information processing functions are integrated into one device. After processing, infrared environment position positioning information can be formed. The radiation intensity of the detection target is detected through the curved surface ball sensing site, realizing multi-dimensional acquisition of light field information and target distance characteristic information.

[0032] The application of the rare earth nickelate electronic phase change oxide curved surface coated composite material prepared according to the method as described above is characterized in that aluminum oxide, titanium oxide, zirconium oxide, hafnium oxide, and garnet ferrite with a certain curved surface shape are used as the core and their surface is modified to improve the surface adsorption effect on the specific crystal plane of the rare earth nickelate oxide, and after mixing them with rare earth and nickel element precursors and a specific flux, a rare earth nickelate polycrystalline layer is used to coat the surface of the above-mentioned core that does not have a crystal coherent relationship through a flux reaction; the metal-insulator transition characteristics of the prepared composite material and the functional characteristics of the core material can achieve multi-dimensional functional response under the design and regulation of an external field, and the shell layer of the composite material with a core-shell structure has electronic phase change functional characteristics under external field triggering, and can cooperate with the functional characteristics of the core material, thereby realizing intelligent electromagnetic shielding, optical design and infrared camouflage, optical anti-counterfeiting, external field sensitive resistors, logic electronic devices, and catalytic functions.

[0033] After extensive and in-depth research, the present invention has achieved the preparation and application of rare earth nickelate electronic phase change oxide curved surface coating composite materials. The present invention reduces the forward Gibbs free energy of rare earth nickelate through chemical adsorption, and forms a coating polycrystalline layer on the curved surface core with different crystal structures and no lattice matching relationship. By designing the core material morphology, changing the surface treatment process, and doping the coating layer components, the coupling application of the core material properties and the rare earth nickelate properties is achieved; it has application value in intelligent electromagnetic shielding, optical design and infrared camouflage, optical anti-counterfeiting, external field sensitive resistors, logic electronic devices, catalysis, and high-temperature superconductivity. Compared with previous composite technologies, the technology provided by the present invention has the advantages of realizing inorganic functional material coating of curved surface cores and the ability to design complex devices based on application scenarios in combination with electronic phase change properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a photograph of alumina (Al2O3) pellets coated with neodymium nickelate (NdNiO3) using the method of the present invention.

[0035] Figure 2 The resistance-temperature curve of alumina (Al2O3) pellets coated with neodymium nickelate (NdNiO3) using the method of the present invention is shown.

[0036] Figure 3 The figure shows the resistance-temperature relationship curve of ceramic fiber coated with samarium nickelate (SmNiO3) using the method of the present invention.

[0037] Figure 4 In order to coat yttrium iron garnet (Y3Fe5O3) with praseodymium nickelate (PrNiO3) by the method of the present invention, 12 )The resistance-temperature curve of the ball.

[0038] Figure 5The resistance-temperature relationship curve of alumina (Al2O3) spheres coated with single-layer perovskite structure lanthanum nickelate (La2NiO4) using the method of the present invention.

[0039] Figure 6 The resistance-temperature relationship curve of aluminum oxide (Al2O3) balls coated with double-layer perovskite structure lanthanum nickelate (La3Ni2O7) using the method of the present invention.

[0040] Figure 7 The present invention provides a grazing incidence X-ray diffraction pattern of aluminum oxide (Al2O3) coated with neodymium nickelate (NdNiO3) using the method of the present invention.

[0041] Figure 8 This is a scanning electron microscope image of a 40-micron diameter aluminum oxide (Al2O3) sphere coated with samarium nickelate (SmNiO3) using the method of the present invention.

[0042] Figure 9 This is a scanning electron microscope image of a 3-micron diameter aluminum oxide (Al2O3) ceramic fiber coated with samarium nickelate (SmN iO3) using the method of the present invention.

[0043] Figure 10 The diagram is a schematic diagram of the polarization electric field triggering principle of coating the dielectric layer of the curved ball array with rare earth nickelate electronic phase change oxide using the method of the present invention.

[0044] Figure 11 This is a schematic diagram of the stress triggering principle of coating the piezoelectric layer of a curved sphere with rare earth nickelate electronic phase change oxide using the method of the present invention.

[0045] Figure 12 This is a schematic diagram of the terahertz microwave modulation principle of a quasi-photonic crystal array of curved small balls coated with rare earth nickelate electronic phase change oxides according to the method of the present invention.

[0046] Figure 13 This is a schematic diagram of infrared position detection and positioning sensing using a rare earth nickelate electronic phase change oxide-coated curved ball compound eye array. DETAILED DESCRIPTION

[0047] Unless otherwise specified, the various raw materials of the present invention can be obtained commercially or prepared according to conventional methods in the art. Unless otherwise defined or indicated, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein can be applied to the methods of the present invention.

[0048] Other aspects of the invention will be apparent to those skilled in the art in view of the disclosure herein.

[0049] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present invention only and are not intended to limit the scope of the invention. The experimental methods in the following examples, for which no specific conditions are specified, are generally carried out under conventional conditions or under conditions recommended by the manufacturer.

[0050] Test methods: XRD, SEM, CTA, and PPMS were used to characterize the prepared materials. The characterization methods were performed according to common standards in the field.

[0051] Example-1:

[0052] In order to realize the intelligent control of the infrared emissivity of composite materials in the atmospheric window band, Nd x Sm 1-x NiO3 (0≤x≤1) coated ultra-white alumina spheres with high infrared emissivity in the atmospheric window band. Using ultra-white alumina spheres with a diameter of 500μm as the core material, nickel oxide, neodymium oxide, and samarium oxide as precursors, and potassium chloride as molten salt, the spheres were reacted at 7 MPa oxygen pressure and 800 degrees Celsius for 24 hours before being removed. The resulting composite material is shown in the following photo. Figure 1 The resistivity-temperature relationship is shown in Figure 2 As shown, the grazing incidence X-ray diffraction pattern is as follows Figure 7 As shown. Nd with polycrystalline structure 0.4 Sm 0.6 NiO3 is evenly coated on the surface of the ultra-white alumina ball, and the whole ball exhibits metal-insulator phase transition characteristics at 302K. When the temperature is lower than 302K, Nd 0.4 Sm 0.6 NiO3 has high infrared transmittance in the atmospheric window band of interest. Since alumina has high infrared emission in this band, the composite material exhibits overall high radiation characteristics. When the temperature is higher than 302K, Nd 0.4 Sm 0.6 NiO3 has low infrared transmittance in the atmospheric window band of interest, which suppresses the infrared emission of ultra-white alumina and makes the composite material exhibit overall low radiation characteristics.

[0053] Example-2:

[0054] In order to achieve the temperature-induced infrared color-tuning characteristics in a wide temperature range of 100-600K, a series of PrNiO3, NdNiO3, Nd 0.5 Sm 0.5 NiO3、Nd 0.4 Sm 0.6NiO3, SmNiO3, EuNiO3, and GdNiO3 are coated with Zr-doped alumina beads with a curvature radius of 10 μm to 1 mm, respectively. The electron scanning microscope photos of the surface of the SmNiO3 coated alumina beads with a diameter of 40 μm are shown in the figure. Figure 8 As shown. To prepare PrNiO3-coated Zr-doped alumina beads with a diameter of 600 μm, praseodymium oxide and nickel oxide were used as precursors, potassium carbonate was used as molten salt, and the reaction was carried out at 4 MPa and 800 degrees Celsius for 24 hours. To prepare NdNiO3-coated Zr-doped alumina beads with a diameter of 100 μm, neodymium oxide and nickel oxide were used as precursors, potassium chloride was used as molten salt, and the reaction was carried out at 5 MPa and 800 degrees Celsius for 24 hours. To prepare SmNiO3-coated Zr-doped alumina beads with a diameter of 800 μm, samarium nitrate and nickel nitrate were used as precursors, potassium chloride was used as molten salt, and the reaction was carried out at 7 MPa and 900 degrees Celsius for 36 hours. To prepare EuNiO3-coated Zr-doped alumina beads with a diameter of 1 mm, europium oxide and nickel oxide were used as precursors, lithium chloride and sodium chloride were used as molten salt, and the reaction was carried out at 12 MPa and 900 degrees Celsius for 36 hours. To prepare GdNiO3-coated Zr-doped alumina spheres with a diameter of 1 mm, gadolinium oxide and nickel oxide were used as precursors, and lithium chloride was used as a molten salt. The reaction was carried out at 15 MPa and 900 degrees Celsius for 48 hours. This rare earth nickelate exhibits an insulating phase below the metal-insulator transition temperature, with high infrared reflectivity and low infrared transmittance; above the metal-insulator transition temperature, it exhibits a metallic phase with low infrared reflectivity and high infrared transmittance. These Zr-doped alumina spheres coated with rare earth nickelates containing different rare earth elements and metal-insulator transition temperatures were arranged into a photonic crystal planar array. By adjusting the arrangement, the overall planar pattern of high and low infrared reflectivity was controlled at different temperatures. This enabled temperature-triggered infrared imaging differentiation of pixels in different planes, enabling anti-counterfeiting, optical design, and infrared camouflage functions.

[0055] Example-3:

[0056] In order to realize the self-protection function of ferrite frequency modulation devices, PrNiO3, NdNiO3, Nd x Sm 1-x NiO3 (x = 0.1, 0.2, 0.3, 0.4), SmNiO3, EuNiO3, GdNiO3 are coated with yttrium iron garnet (YIG) balls with a curvature radius of 50μm to 8mm, among which the resistance-temperature relationship of the YIG ball with a diameter of 200μm coated by PrNiO3 is as follows: Figure 4To prepare PrNiO3 coated YIG beads with a diameter of 200 μm, nickel oxide and praseodymium oxide were used as precursors, potassium chloride was used as molten salt, and the reaction was carried out at 6 MPa and 800 degrees Celsius for 24 hours; to prepare NdNiO3 coated YIG beads with a diameter of 150 μm, nickel oxide and samarium oxide were used as precursors, potassium chloride was used as molten salt, and the reaction was carried out at 6 MPa and 800 degrees Celsius for 30 hours; to prepare Nd x Sm 1-x NiO3 (x = 0.1, 0.2, 0.3, 0.4) coated YIG beads with a diameter of 100 μm were prepared using nickel oxide, neodymium oxide, and samarium oxide as precursors, potassium chloride as a molten salt, and a reaction temperature of 6 MPa and 800°C for 36 hours. To prepare SmNiO3 coated YIG beads with a diameter of 700 μm, samarium nitrate and nickel nitrate were used as precursors, potassium chloride was used as a molten salt, and a reaction temperature of 9 MPa and 900°C for 36 hours. To prepare EuNiO3 coated YIG beads with a diameter of 2 mm, europium acetate and nickel acetate were used as precursors, sodium chloride was used as a molten salt, and a reaction temperature of 10 MPa and 900°C for 36 hours. To prepare GdNiO3 coated YIG beads with a diameter of 1 mm, gadolinium nitrate and nickel nitrate were used as precursors, lithium chloride was used as a molten salt, and a reaction temperature of 12 MPa and 1000°C for 48 hours. Under the influence of applied microwave power, YIG heats up, raising its temperature below the metal-insulator transition temperature. The rare earth nickelate then assumes an insulating phase, providing no significant shielding against the applied microwaves. However, when the temperature rises above the metal-insulator transition temperature, the rare earth nickelate transforms into a metallic phase, improving its microwave shielding effectiveness. This enables the self-protection function of ferrite frequency modulation devices. By manipulating the rare earth element composition and controlling the metal-insulator transition temperature of the coating layer, the critical power density can be adjusted.

[0057] Example-4:

[0058] In order to realize the application of sudden change thermistor devices in different scenarios, a series of Pr x Sm 1-x NiO3(0≤x≤1), Pr x Nd 1-x NiO3(0≤x≤1), Nd x Sm 1-x NiO3(0≤x≤1), Sm x Eu 1-x NiO3 (0≤x≤1) and other rare earth element doped nickelates are coated with aluminum oxide, zirconium oxide, hafnium oxide small balls or small cylinders with a curvature radius of 5μm to 5mm. x Sm 1-x NiO3 coating layer, using praseodymium oxide, nickel oxide, samarium oxide as precursors, potassium chloride as molten salt, reacting at 6 MPa and 900 degrees Celsius for 20 hours;x Nd 1-x NiO3 coating layer, using neodymium acetate, praseodymium acetate, nickel acetate as precursors, potassium chloride as molten salt, reacting at 6 MPa and 950 degrees Celsius for 24 hours; x Sm 1-x NiO3 coating layer, using samarium nitrate, neodymium nitrate, nickel nitrate as precursors, potassium carbonate as molten salt, reacting at 7 MPa and 900 degrees Celsius for 36 hours; x Eu 1-x The NiO3 coating is prepared using europium oxide, samarium oxide, and nickel oxide as precursors, lithium chloride and sodium chloride as molten salts, and reacting at 900 degrees Celsius at 9 MPa for 36 hours. The prepared composite materials, made of rare earth nickelates doped with various rare earth elements and coated with aluminum oxide, zirconium oxide, or hafnium oxide pellets or cylinders, exhibit a metal-insulator phase transition temperature range of 100 to 600 K. As the ionic radius of the rare earth element decreases, the phase transition temperature of the rare earth nickelate gradually increases, and the resistivity change caused by the metal-insulator phase transition also increases. In summary, by varying the type and doping amount of the rare earth element, the electronic phase transition temperature range of the rare earth nickelate can be continuously controlled, enabling precise design of the thermistor's sudden change temperature based on the application scenario.

[0059] Example-5:

[0060] In order to realize infrared camouflage technology such as thermal deception and optical design anti-counterfeiting, the material is driven by temperature to undergo a reversible phase change, thereby realizing dynamic regulation of the material's own infrared emissivity. x Sm 1-x NiO3 (x = 0.1, 0.2, 0.3, 0.4, 0.5), SmNiO3, EuNiO3, GdNiO3 coated titanium dioxide beads with a curvature radius of 50 μm to 1 mm. x Sm 1-xNiO3 (x = 0.1, 0.2, 0.3, 0.4, 0.5) coated titanium dioxide spheres with a diameter of 500 μm, using nickel oxide, neodymium oxide, and samarium oxide as precursors, potassium chloride as molten salt, and reacting at 7 MPa and 880 degrees Celsius for 30 hours; to prepare SmNiO3 coated titanium dioxide spheres with a diameter of 800 μm, samarium nitrate and nickel nitrate as precursors, potassium chloride as molten salt, and reacting at 7 MPa and 900 degrees Celsius for 40 hours; to prepare EuNiO3 coated titanium dioxide spheres with a diameter of 900 μm, europium oxide and nickel oxide as precursors, sodium chloride as molten salt, and reacting at 7 MPa and 900 degrees Celsius for 42 hours. To prepare GdNiO3-coated titanium dioxide spheres with a diameter of 1 mm, gadolinium nitrate and nickel nitrate were used as precursors, and lithium chloride was used as a molten salt. The reaction was carried out at 10 MPa and 950 degrees Celsius for 48 hours. By leveraging the temperature-independent infrared emission characteristics of rare earth nickelates within the metal-insulator phase transition temperature range, the target emissivity was adaptively controlled to adapt to temperature changes in different regions, thus achieving intelligent dynamic infrared camouflage for the composite material.

[0061] Example-6:

[0062] In order to realize the application of composite materials in marine electric field sensing or neuron logic devices, ceramic fibers with fiber diameters of 1μm to 50μm are coated with NdNiO3, SmNiO3, and EuNiO3 respectively. The resistivity-temperature relationship of ceramic fibers with a fiber diameter of 3μm coated with SmNiO3 is as follows: Figure 3 As shown in the scanning electron microscope photos Figure 9 As shown. To prepare the NdNiO3 coating, neodymium nitrate and nickel nitrate are used as precursors, sodium carbonate is used as molten salt, and the reaction is carried out at 3.5 MPa and 850 degrees Celsius for 20 hours; to prepare the SmNiO3 coating, samarium nitrate and nickel nitrate are used as precursors, potassium chloride is used as molten salt, and the reaction is carried out at 6.5 MPa and 860 degrees Celsius for 36 hours; to prepare the EuNiO3 coating, europium acetate and nickel acetate are used as precursors, lithium chloride and sodium chloride are used as molten salt, and the reaction is carried out at 8 MPa and 900 degrees Celsius for 40 hours. After the rare earth nickelate is hydrogenated, the Ni based 3+ The electron itinerant state becomes based on Ni 2+ The electron localization state increases resistivity by several orders of magnitude, and the hydrogenation process is reversible while maintaining high proton conductivity. The ultrahigh sensitivity brought about by the tiny size of hydrogen ions enables ultrafast and precise responses to external signals. When an electrical bias is applied through proton conduction, the rare earth nickelate resistor responds, enabling the composite material to be used in marine sensors or neuron logic devices.

[0063] Example-7:

[0064] In order to realize thermistor devices for application in different scenarios, a series of nickelates doped with rare earth elements or alkaline earth elements in the form of single-layer perovskite structure nickelates (Re2NiO4) are used to coat aluminum oxide, zirconium oxide, hafnium oxide small balls or small cylinders with a curvature radius of 5μm to 5mm. To prepare the LaPrNiO4 coating layer, lanthanum oxide, praseodymium oxide, and nickel oxide are used as precursors, potassium chloride is used as molten salt, and the reaction is carried out at 0.1 MPa oxygen pressure and 1200 degrees Celsius for 24 hours; to prepare the PrSrNiO4 coating layer, strontium acetate, nickel acetate, and praseodymium acetate are used as precursors, potassium chloride is used as molten salt, and the reaction is carried out at 0.1 MPa oxygen pressure and 1200 degrees Celsius for 24 hours; to prepare the NdSrNiO4 coating layer, neodymium oxide, strontium oxide, and nickel oxide are used as precursors, potassium carbonate is used as molten salt, and the reaction is carried out at 0.1 MPa oxygen pressure and 1200 degrees Celsius for 24 hours. To prepare the EuSrNiO4 coating layer, europium oxide, strontium oxide, and nickel oxide are used as precursors, potassium carbonate is used as molten salt, and the reaction is carried out at 0.5 MPa oxygen pressure and 1200 degrees Celsius for 36 hours; to prepare the GaBaNiO4 coating layer, gadolinium oxide, barium oxide, and nickel oxide are used as precursors, potassium chloride is used as molten salt, and the reaction is carried out at 1 MPa oxygen pressure and 1300 degrees Celsius for 24 hours; by changing the type of elements and the doping amount, the electronic phase transition temperature range of the coating layer can be controlled.

[0065] Example-8:

[0066] To realize the sensing device that can monitor human body temperature, Nd 0.5 Sm 0.5 NiO3 coated ceramic fibers with a diameter of 1μm to 50μm. 0.5 Sm 0.5 The NiO3 coating layer uses nickel oxide, neodymium oxide, and samarium oxide as precursors and potassium chloride as molten salt, and reacts at 6 MPa and 800 degrees Celsius for 36 hours. The flexible sensor with ceramic fiber fabric as the base has different resistivity corresponding to different temperature changes. The temperature sensitivity around the phase transition temperature is particularly accurate. It can monitor external stimuli and convert them into accurately identifiable electrical signals, providing a basis for the digitalization of various application scenarios.

[0067] Example-9:

[0068] In order to realize the treatment of industrial-grade wastewater by adsorbing active oxygen using anodic oxidation, a series of PrNiO3, NdNiO3, SmNiO3, EuNiO3, GdNiO3, DyNiO3, and HoNiO3 were used to coat alumina balls with an average diameter of 1 mm. To prepare the PrNiO3 coating layer, praseodymium oxide and nickel oxide are used as precursors, potassium carbonate is used as molten salt, and the reaction is carried out at 4 MPa and 800 degrees Celsius for 24 hours; to prepare the NdNiO3 coating layer, neodymium oxide and nickel oxide are used as precursors, potassium chloride is used as molten salt, and the reaction is carried out at 5 MPa and 800 degrees Celsius for 24 hours; to prepare the SmNiO3 coating layer, samarium nitrate and nickel nitrate are used as precursors, potassium chloride is used as molten salt, and the reaction is carried out at 7 MPa and 900 degrees Celsius for 36 hours; to prepare the EuNiO3 coating layer, europium oxide and nickel oxide are used as precursors, lithium chloride and sodium chloride are used as molten salts, and the reaction is carried out at 7 MPa and 900 degrees Celsius for 36 hours. To prepare the GdNiO3 coating, gadolinium oxide and nickel oxide are used as precursors, and lithium chloride is used as a molten salt, reacting at 900 degrees Celsius at 9 MPa for 48 hours. To prepare the DyNiO3 coating, dysprosium nitrate and nickel nitrate are used as precursors, and a mixture of lithium chloride and potassium chloride is used as a molten salt, reacting at 900 degrees Celsius at 10 MPa for 48 hours. To prepare the HoNiO3 coating, holmium nitrate and nickel nitrate are used as precursors, and lithium chloride is used as a molten salt, reacting at 900 degrees Celsius at 10 MPa for 48 hours. Anodic oxidation catalysis is performed using appropriate rare earth nickelates tailored to the industrial wastewater temperatures. In a water purification tank filled with rare earth nickelate-coated alumina spheres, the reactive oxygen species physically adsorbed on the anode surface of the rare earth nickelates oxidizes the pollutants, ultimately degrading them into low-biotoxic or readily biodegradable substances, or even directly mineralizing them into inorganic substances, thus achieving the goal of industrial wastewater treatment.

[0069] Example-10:

[0070] In order to realize superconducting material related devices used in different scenarios, La3Ni2O7 and La4Ni3O 10 Superconducting properties under pressure. Layered perovskite structure nickelates are coated with aluminum oxide, zirconium oxide, hafnium oxide small balls or small cylinders with a curvature radius of 5μm to 5mm. To prepare the La3Ni2O7 coating layer, lanthanum oxide and nickel oxide are used as precursors and potassium chloride is used as molten salt. The reaction is carried out under 0.1 MPa oxygen pressure and 1100 degrees Celsius for 24 hours. To prepare La4Ni3O 10 The coating layer uses lanthanum acetate and nickel acetate as precursors and potassium chloride as molten salt, and reacts under 0.1 MPa oxygen pressure and 1000 degrees Celsius for 24 hours; by changing the ambient pressure, the temperature range in which the coating layer undergoes zero-resistance superconductivity can be controlled.

[0071] Example-11:

[0072] To realize abrupt thermistor devices for different applications, La3Ni2O7 was used to achieve a sharper temperature-triggered resistivity mutation characteristic than the heavy rare earth component 113-type rare earth nickel-based perovskite oxide within a high temperature range. A series of nickelates with equal rare earth elements or alkaline earth elements doped in rare earth positions, or transition elements doped in nickel positions, were coated with alumina, zirconium oxide, and hafnium oxide pellets or small cylinders with a curvature radius of 5μm to 5mm. The resistance-temperature relationship of the La3Ni2O7-coated alumina pellet with a diameter of 200μm is shown in the following figure: Figure 6 As shown. 2.7 Pr 0.3 To prepare the Ni2O7 coating layer, lanthanum oxide, praseodymium oxide, and nickel oxide are used as precursors, potassium chloride is used as molten salt, and the reaction is carried out at 0.1 MPa oxygen pressure and 1100 degrees Celsius for 24 hours; to prepare the La3Ni2O7 coating layer, lanthanum acetate and nickel acetate are used as precursors, potassium chloride is used as molten salt, and the reaction is carried out at 0.1 MPa oxygen pressure and 1100 degrees Celsius for 24 hours; to prepare the La 3-x Bi x The Ni2O7 coating layer uses lanthanum oxide, bismuth oxide, and nickel oxide as precursors and potassium carbonate as molten salt, and reacts at 0.1 MPa oxygen pressure and 1100 degrees Celsius for 36 hours. As the Bi doping amount increases, the La 3-x Bi x The metal-insulator transition temperature of Ni2O7 gradually decreases. By varying the type and doping level of the element, the electronic phase transition temperature range of the coating layer can be controlled, enabling precise design of the thermistor's transition temperature based on the application scenario.

[0073] Example-12:

[0074] In order to realize thermistor devices, single-layer perovskite structure nickelate La2NiO4 is used to coat alumina, zirconium oxide, hafnium oxide small balls or small cylinders with a curvature radius of 5μm to 5mm. The resistance-temperature relationship of La2NiO4 coated alumina small balls with a curvature radius of 20μm is as follows: Figure 5 To prepare the La2NiO4 coating, lanthanum oxide and nickel oxide are used as precursors, potassium chloride is used as a molten salt, and the reaction is carried out at 1200 degrees Celsius and 0.1 MPa of oxygen pressure for 30 hours. By varying the growth time, the electronic phase transition temperature of the coating can be controlled.

[0075] Example-13:

[0076] To realize thermistor devices applicable in different scenarios, nickelates with a single-layer perovskite structure (Re2NiO4) doped with a series of rare-earth elements or alkaline-earth elements at the rare-earth sites are used to coat alumina, zirconia, hafnium oxide spheres or small cylinders with a radius of curvature of 5 μm to 5 mm. To prepare the La2Co x Ni 1-x O4 (0 < x ≤ 0.3) coating, lanthanum oxide, cobalt oxide, and nickel oxide are used as precursors, potassium chloride is used as a molten salt, and the reaction is carried out at 0.1 megapascal oxygen pressure and 1200 °C for 24 hours; to prepare the La2Fe x Ni 1-x O4 (0 < x ≤ 0.3) coating, iron acetate, nickel acetate, and lanthanum acetate are used as precursors, potassium chloride is used as a molten salt, and the reaction is carried out at 0.1 megapascal oxygen pressure and 1200 °C for 24 hours; to prepare the La2V x Ni 1-x O4 (0 < x ≤ 0.3) coating, lanthanum oxide, vanadium oxide, and nickel oxide are used as precursors, potassium carbonate is used as a molten salt, and the reaction is carried out at 0.1 megapascal oxygen pressure and 1350 °C for 36 hours; to prepare the La2Mn x Ni 1-x O4 (0 < x ≤ 0.3) coating, manganese oxide, lanthanum oxide, and nickel oxide are used as precursors, potassium carbonate is used as a molten salt, and the reaction is carried out at 0.5 megapascal oxygen pressure and 1460 °C for 36 hours; by changing the types of elements, doping amounts, and growth times, the electronic phase transition temperature range of the coating can be regulated.

[0077] Example - 14:

[0078] To realize thermistor devices applicable in different scenarios, nickelates with a double-layer perovskite structure (Re3Ni2O7) doped with a series of rare-earth elements or alkaline-earth elements at the rare-earth sites are used to coat alumina, zirconia, hafnium oxide spheres or small cylinders with a radius of curvature of 5 μm to 5 mm. To prepare the La3Co x Ni 2-x O7 (0 < x ≤ 0.3) coating, lanthanum oxide, cobalt oxide, and nickel oxide are used as precursors, potassium chloride is used as a molten salt, and the reaction is carried out at 0.1 megapascal oxygen pressure and 1180 °C for 24 hours; to prepare the La3Fe x Ni 2-x O7 (0 < x ≤ 0.3) coating, iron acetate, nickel acetate, and lanthanum acetate are used as precursors, potassium chloride is used as a molten salt, and the reaction is carried out at 0.1 megapascal oxygen pressure and 1200 °C for 24 hours; to prepare the La3V x Ni 2- xO7 (0 < x ≤ 0.3) coating layer, using lanthanum oxide, vanadium oxide, nickel oxide as precursors, potassium carbonate as molten salt, reacting for 36 hours under 0.1 megapascal oxygen pressure and 1350 degrees Celsius; for preparing La3Mn x Ni 2-x O7 (0 < x ≤ 0.3) coating layer, using manganese oxide, lanthanum oxide, nickel oxide as precursors, potassium carbonate as molten salt, reacting for 36 hours under 0.5 megapascal oxygen pressure and 1200 degrees Celsius; the electron phase transition temperature range of the coating layer can be regulated by changing the element types, doping amounts and growth times.

[0079] Example - 15:

[0080] To realize thermistor devices applied in different scenarios, using a series of nickelates with perovskite structure doped with multiple rare earth elements or alkaline earth elements in the rare earth site to coat alumina, zirconia, hafnium oxide spheres or small cylinders with a curvature radius of 5 μm to 5 mm respectively. For preparing La4Co 10 ) Ni x Ni 3-x O 10 (0 < x ≤ 0.3) coating layer, using lanthanum oxide, cobalt oxide, nickel oxide as precursors, potassium chloride as molten salt, reacting for 24 hours under 0.1 megapascal oxygen pressure and 1300 degrees Celsius; for preparing La4Fe x Ni 3-x O 10 (0 < x ≤ 0.3) coating layer, using iron acetate, nickel acetate, lanthanum acetate as precursors, potassium chloride as molten salt, reacting for 24 hours under 0.1 megapascal oxygen pressure and 1500 degrees Celsius; for preparing La3V x Ni 3- x O 10 (0 < x ≤ 0.3) coating layer, using lanthanum oxide, vanadium oxide, nickel oxide as precursors, potassium carbonate as molten salt, reacting for 36 hours under 0.1 megapascal oxygen pressure and 1200 degrees Celsius; for preparing La2Mn x Ni 1-x O4 (0 < x ≤ 0.3) coating layer, using manganese oxide, lanthanum oxide, nickel oxide as precursors, potassium carbonate as molten salt, reacting for 36 hours under 0.5 megapascal oxygen pressure and 1200 degrees Celsius; the resistance - temperature relationship change range of the coating layer can be regulated by changing the element types, doping amounts and growth times.

[0081] Example - 16:

[0082] In order to realize the application of the metal-insulator phase change process of composite spheres triggered by polarization electric field, a series of PrNiO3, NdNiO3, SmNiO3, EuNiO3, and GdNiO3 are used to coat a number of alumina spheres with an average diameter of 10μm, which are arranged and dispersed in an organic polymer with dielectric properties. The organic polymer is solidified to form a polymer / composite sphere layer with a thickness of about 50 microns, which is compounded between dielectric layers. An electric field is applied to the electrode to form a polarization electric field between the layers to trigger the metal-insulator phase change of the composite spheres, thereby achieving a sudden drop in resistivity and thus achieving a breakdown effect. The principle diagram is shown as follows: Figure 10 To prepare the PrNiO3 coating layer, praseodymium oxide and nickel oxide are used as precursors, potassium chloride is used as molten salt, and several small balls are placed in the precursor powder, and reacted at 5 MPa and 800 degrees Celsius for 24 hours; to prepare the NdNiO3 coating layer, neodymium nitrate and nickel nitrate are used as precursors, potassium chloride is used as molten salt, and several small balls are placed in the precursor powder, and reacted at 6 MPa and 820 degrees Celsius for 36 hours; to prepare the SmNiO3 coating layer, samarium nitrate and nickel nitrate are used as precursors, potassium chloride is used as molten salt, and several small balls are placed in the precursor powder, and reacted at 6.5 MPa and 860 degrees Celsius for 36 hours. Celsius conditions for 36 hours; to prepare the EuNiO3 coating layer, europium acetate and nickel acetate are used as precursors, potassium chloride is used as molten salt, and several small balls are placed in the precursor powder, and reacted at 7 MPa and 900 degrees Celsius for 36 hours; to prepare the GdNiO3 coating layer, gadolinium oxide and nickel oxide are used as precursors, and a mixture of lithium chloride and potassium chloride is used as molten salt, and several small balls are placed in the precursor powder, and reacted at 7 MPa and 900 degrees Celsius for 48 hours; by changing the type of elements, doping amount and growth time, the electronic phase transition temperature range of the coating layer can be controlled.

[0083] Example-17:

[0084] In order to realize the application of stress-triggered metal-insulator phase change of composite spheres, a series of PrNiO3, NdNiO3, SmNiO3, EuNiO3, and GdNiO3 are used to coat a number of alumina spheres with an average diameter of 30μm. These spheres are arranged and dispersed in an organic polymer with conductive properties. The organic polymer is solidified to form a polymer / composite sphere layer with a thickness of about 150 microns. The polymer / composite sphere layer is then composited between dielectric layers. Stress is applied to the electrode to trigger the metal-insulator phase change of the interlayer composite spheres, achieving a sudden drop in resistivity. The principle diagram is shown in the figure. Figure 11To prepare the PrNiO3 coating layer, praseodymium oxide and nickel oxide are used as precursors, potassium chloride is used as molten salt, and several small balls are placed in the precursor powder, and reacted at 5 MPa and 800 degrees Celsius for 24 hours; to prepare the NdNiO3 coating layer, neodymium nitrate and nickel nitrate are used as precursors, potassium chloride is used as molten salt, and several small balls are placed in the precursor powder, and reacted at 6 MPa and 820 degrees Celsius for 36 hours; to prepare the SmNiO3 coating layer, samarium nitrate and nickel nitrate are used as precursors, potassium chloride is used as molten salt, and several small balls are placed in the precursor powder, and reacted at 6.5 MPa and 860 degrees Celsius for 36 hours. Celsius conditions for 36 hours; to prepare the EuNiO3 coating layer, europium acetate and nickel acetate are used as precursors, potassium chloride is used as molten salt, and several small balls are placed in the precursor powder, and reacted at 7 MPa and 900 degrees Celsius for 36 hours; to prepare the GdNiO3 coating layer, gadolinium oxide and nickel oxide are used as precursors, and a mixture of lithium chloride and potassium chloride is used as molten salt, and several small balls are placed in the precursor powder, and reacted at 7 MPa and 900 degrees Celsius for 48 hours; by changing the type of elements, doping amount and growth time, the electronic phase transition temperature range of the coating layer can be controlled.

[0085] Example-18:

[0086] In order to realize the frequency modulation of infrared-terahertz microwaves, Nd x Sm 1-x NiO3 (0≤x≤1) coated alumina balls with diameters of 30μm to 3mm and arranged as follows Figure 12 The multilayer array is connected to the sensor and processor to complete the reception and processing of information. 0.25 Sm 0.75 NiO3 coated alumina balls with a diameter of 100 μm, using nickel oxide, neodymium oxide, praseodymium oxide as precursors, potassium chloride as molten salt, reacted at 6 MPa and 800 degrees Celsius for 36 hours; 0.75 Sm 0.25 NiO3 coated alumina beads with a diameter of 50 μm, using nickel oxide, neodymium oxide, praseodymium oxide as precursors, potassium chloride as molten salt, reacted at 5 MPa and 800 degrees Celsius for 24 hours; 0.5 Sm 0.5 NiO3 coated alumina balls with a diameter of 300 μm, using nickel oxide, neodymium oxide, praseodymium oxide as precursors, potassium chloride as molten salt, reacted at 6 MPa and 900 degrees Celsius for 48 hours; 0.33 Sm 0.67NiO3-coated alumina beads with a diameter of 500μm use nickel oxide, neodymium oxide, and praseodymium oxide as precursors and potassium chloride as molten salt, reacting at 7 MPa and 900 degrees Celsius for 36 hours. Frequency modulation of infrared-terahertz microwaves from incident to reflection and transmission can be achieved, and the frequency modulation range can be calculated and adjusted by regulating the rare earth element composition to control the metal-insulator phase transition temperature of the coating layer and the particle size of the beads.

[0087] Example-19:

[0088] In order to realize the compound eye position detection sensor in the infrared band, Pr x Nd 1-x NiO3 (0≤x≤1) coated alumina balls with a diameter of 1μm to 1mm and arranged as follows Figure 13 The hemispherical shape of the schematic diagram is then connected to the sensor and processor to complete the reception and processing of information. 0.5 Nd 0.5 NiO3 coated alumina beads with a diameter of 100 μm, using nickel oxide, neodymium oxide, and praseodymium oxide as precursors, potassium chloride as molten salt, reacted at 6 MPa and 800 degrees Celsius for 36 hours; 0.2 Nd 0.8 NiO3 coated alumina beads with a diameter of 50 μm, using nickel oxide, neodymium oxide, praseodymium oxide as precursors, potassium chloride as molten salt, reacted at 5 MPa and 800 degrees Celsius for 24 hours; 0.3 Nd 0.7 NiO3 coated alumina beads with a diameter of 300 μm, using nickel oxide, neodymium oxide, praseodymium oxide as precursors, potassium chloride as molten salt, reacted at 6 MPa and 900 degrees Celsius for 48 hours; 0.6 Nd 0.4 NiO3-coated alumina beads with a diameter of 500μm use nickel oxide, neodymium oxide, and praseodymium oxide as precursors, potassium chloride as molten salt, and react at 7 MPa and 900 degrees Celsius for 36 hours. It can realize the compound eye position detection sensing function in the infrared band, and by controlling the metal insulator phase transition temperature of the coating layer and the particle size of the beads by regulating the rare earth element composition, the detection and reception infrared wavelength range can be adjusted.

[0089] Example-20:

[0090] In order to achieve the contactless triggering of the electronic phase transition of rare earth nickelate by alternating magnetic field, magnetic particles are filled into the interior of the alumina ball. The heat generated by the eddy current and hysteresis of the magnetic particles under the alternating magnetic field is used to raise the core temperature to the ReNiO3 phase transition temperature, thereby triggering the outer metal-insulator transition. x Sm 1-xNiO3 (x = 0.1, 0.2, 0.3, 0.4), SmNiO3, EuNiO3, GdNiO3 are coated on magnetic particle / alumina composite beads with a curvature radius of 50μm to 8mm. To prepare PrNiO3 coated composite beads with a diameter of 200μm, nickel oxide and praseodymium oxide are used as precursors, potassium chloride is used as molten salt, and the reaction is carried out at 6 MPa and 800 degrees Celsius for 24 hours; to prepare NdNiO3 coated composite beads with a diameter of 150μm, nickel oxide and samarium oxide are used as precursors, potassium chloride is used as molten salt, and the reaction is carried out at 6 MPa and 800 degrees Celsius for 30 hours; to prepare Nd x Sm 1-x NiO3 (x = 0.1, 0.2, 0.3, 0.4)-coated composite spheres with a diameter of 100 μm were prepared using nickel oxide, neodymium oxide, and samarium oxide as precursors and potassium chloride as a molten salt at 6 MPa and 800 degrees Celsius for 36 hours. To prepare SmNiO3-coated composite spheres with a diameter of 700 μm, samarium nitrate and nickel nitrate were used as precursors and potassium chloride as a molten salt at 900 degrees Celsius for 36 hours at 9 MPa. To prepare EuNiO3-coated composite spheres with a diameter of 2 mm, europium acetate and nickel acetate were used as precursors and sodium chloride as a molten salt at 10 MPa and 900 degrees Celsius for 36 hours. To prepare GdNiO3-coated composite spheres with a diameter of 1 mm, gadolinium nitrate and nickel nitrate were used as precursors and lithium chloride as a molten salt at 12 MPa and 1000 degrees Celsius for 48 hours. Under the influence of an external alternating magnetic field, the magnetic particles heat up, raising their temperature below the metal-insulator transition temperature, where the rare earth nickelate assumes an insulating phase. When the temperature rises above the metal-insulator transition temperature, the rare earth nickelate transforms into a metallic phase. By manipulating the rare earth element composition and growth time to control the metal-insulator transition temperature, a contactless, external field-triggered metal-insulator phase transition can be achieved.

Claims

1. A method for preparing a rare earth nickelate electronic phase change oxide curved surface coating composite material, characterized in that: The following steps are involved: 1) Design the material composition, electronic phase transition properties, and synergistic mode of the rare earth nickelate with the core material according to the application scenario. Select the core material composition, surface shape and curvature, and size. Improve its surface chemical adsorption of the rare earth nickelate in the thermodynamically metastable phase in molten salt through surface modification. 2) According to the stoichiometric ratio of the metal elements in the selected rare earth nickelate oxide, weigh the corresponding nickel and rare earth element precursor powders, add a certain proportion of molten salt and mix them evenly, and apply the prepared mixed powder to the outside of the core material in step 1) or place the core material in the mixed powder and compact it; 3) heating the precursor powder in a strongly oxidizing atmosphere to uniformly mix the precursor powder in the molten salt, and reducing the original forward Gibbs free energy of the rare earth nickelate through chemical adsorption on the surface of the core material, thereby nucleating and growing a rare earth nickelate polycrystalline coating layer on the surface of the core material; after cooling, removing the prepared composite material composed of the rare earth nickelate polycrystalline layer coating the core material and washing it with a solvent to remove residual molten salt; The crystal structure of the rare earth nickelate includes 113 type perovskite ReN iO3 and layered perovskite Re n+1 Ni n O 3n+1 ; For ReNiO3, its rare earth element Re sites include: praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), yttrium (Y) and the common occupation of the above elements in different proportions; For the layered perovskite structure Re n+1 Ni n O 3n+1 , which mainly include Re2NiO4, Re3Ni2O7, Re4Ni3O corresponding to n=1, 2, 3 10 , its rare earth element Re sites include: lanthanum (La), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), yttrium (Y) and the common occupation of the above elements in different proportions; The core material components include aluminum oxide, titanium oxide, zirconium oxide, hafnium oxide, and garnet ferrite. Its forms include single crystal and polycrystalline ceramic bodies. Its curved surface shapes include sphere, ellipsoid, and cylinder. Its typical size ranges from 1 micron to 1 centimeter.

2. The method for preparing a rare earth nickelate electronic phase change oxide curved surface coating composite material according to claim 1, characterized in that: The nickel and rare earth element precursor powders include nickel oxide, nitrate, acetate and carbonate, and rare earth element oxide, nitrate, acetate and carbonate.

3. The method for preparing a rare earth nickelate electronic phase change oxide curved surface coating composite material according to claim 1, characterized in that: The molten salt includes: potassium chloride (KCl), sodium chloride (NaCl), lithium chloride (LiCl), potassium carbonate (K2CO3), sodium carbonate (Na2CO3) or a mixture thereof.

4. The method for preparing a rare earth nickelate electronic phase change oxide curved surface coating composite material according to claim 1, characterized in that: The functional properties of the core material can be further designed or hollowed out to be filled with functional materials, thereby synergizing the functional properties of the rare earth nickelate coating layer. The core material functions include: high infrared emissivity, microwave absorption, electromagnetic induction, ferroelectricity, and high dielectric properties. The rare earth nickelate coating layer and the core functional properties can be combined in two main ways: 1) Using an external field to trigger the metal-insulator phase transition characteristics of the rare earth nickelate coating layer to achieve reversible shielding of the core function; the external field includes temperature, polarization electric field, light triggering, and atmosphere triggering; 2) The reversible triggering of the metal-insulator phase transition of the rare earth nickelate coating layer is triggered by the coupling of the inner core layer and the external field, thereby realizing a sudden change in the overall optical and electrical properties of the nickelate-coated inner core composite material; the external field includes an alternating electric field and an alternating magnetic field; through the synergy of the above-mentioned functional characteristics of the inner core material and the electronic phase change characteristics of the rare earth nickelate, an intelligent triggering design of the overall functions of critical microwave power, electromagnetic induction, intelligent electromagnetic shielding under polarized electric field triggering, optical design and infrared camouflage, infrared emissivity regulation, and infrared reflectivity regulation can be realized.

5. The method for preparing a rare earth nickelate electronic phase change oxide curved surface coating composite material according to claim 1, characterized in that: The alkaline earth element Ae can be used to partially replace the rare earth sites of the above perovskite and layered perovskite, or other transition elements can be used to partially replace the Ni-site, so as to further regulate the valence state of nickel elements, the electronic structure of materials, the electrical transport properties, and magnetism in the rare earth nickelate coating layer; wherein, the alkaline earth element Ae includes calcium, strontium, and barium; Re 2-x Ae x NiO4, Re 3- x Ae x Ni2O7, Re 4-x Ae x Ni3O 10 The substitution range of the alkaline earth element in Re is 0 < x ≤ 1, Re 1-x Ae x The substitution range of the alkaline earth element in NiO3 is 0 < x ≤ 0.3; the other transition elements are manganese, iron, rhenium, vanadium, and cobalt, and their substitution range for Ni-elements is greater than 0 and less than or equal to 30%.

6. The method for preparing a rare earth nickelate electronic phase change oxide curved surface coating composite material according to claim 1, characterized in that: The external field triggering forms of the electronic phase change characteristics of the rare earth nickelate coating layer include: ambient temperature triggering, applied polarization electric field triggering, chemical environment triggering, applied stress triggering, and core material coupling triggering. By adjusting the composition, curvature radius, thickness, and composite design of the rare earth nickelate coating layer with the core material, the external field threshold range of the electronic phase change triggering is controlled.

7. The method for preparing a rare earth nickelate electronic phase change oxide curved surface coating composite material according to claim 1, characterized in that: The prepared composite material of rare earth nickelate curved surface coated core can be further arranged into an array, and by regulating the array arrangement mode, the overall optical properties, microwave transmission properties, and DC and AC transport properties before and after the electronic phase transition can be adjusted.

8. Application of the rare earth nickelate electronic phase change oxide curved surface coating composite material prepared by the method of claim 1, characterized in that: Aluminum oxide, titanium oxide, zirconium oxide, hafnium oxide, and garnet ferrite with a certain curved surface shape are used as the core and their surface is modified to improve the surface adsorption effect on the rare earth nickelate oxide crystal surface. After mixing them with rare earth, nickel element precursors and molten salt, a rare earth nickelate polycrystalline layer is used to coat the surface of the above-mentioned core that does not have a crystal coherent relationship through a flux reaction; the metal-insulator transition characteristics of the prepared composite material and the functional characteristics of the core material can achieve multi-dimensional functional response under the design and regulation of external field. The shell layer of the composite material with a core-shell structure has the functional characteristics of electronic phase change under external field triggering, and can cooperate with the functional characteristics of the core material, thereby realizing intelligent electromagnetic shielding, optical design and infrared camouflage, optical anti-counterfeiting, external field sensitive resistors, logic electronic devices, and catalytic functions.

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