Preparation method of temperature sensor based on polymer precursor ceramic metasurface

Abstract

The invention belongs to the field of sensitive ceramic metamaterials, and relates to a preparation method of a temperature sensor based on a polymer precursor ceramic metasurface. The method comprises the following steps: 1) preparing a precursor mixed solution of a polymer precursor ceramic sensitive material with adjustable dielectric constant and loss; 2) forming a polymer precursor ceramic microstructure array on the intermediate dielectric layer (2) based on the polymer precursor (mixed solution) prepared in the step 1) to form a metasurface (3); and 3) preparing a high-temperature-resistant metal layer or a high-conductivity composite material layer (1) on the lower surface of the intermediate dielectric layer (2) to obtain the polymer precursor ceramic metasurface temperature sensor. The sensor can be applied to the field of high-temperature extreme environments, and has the characteristics of high temperature resistance, small size, simple preparation process, high sensitivity, wireless and passive properties and the like. The sensor has good universality and can be used in high-temperature extreme environments such as aero-engines, nuclear reactors and thermal power stations.

Description

Technical Field

[0001] The present invention belongs to the field of sensitive ceramic metamaterials, and relates to a preparation method of a temperature sensor based on a polymer precursor ceramic metasurface. Background Art

[0002] Temperature monitoring in high-temperature extreme environments such as aeroengines, nuclear reactors, and thermal power plants is crucial for ensuring the safe operation of equipment, improving efficiency, and optimizing design. However, the extreme environments of high temperature, high pressure, strong oxidation, and strong corrosion pose extremely high requirements for sensitive materials and sensors. Especially for some moving parts and complex components, traditional wired temperature sensors are difficult to meet the needs. Currently, high-temperature temperature sensors mainly include the following three categories: (1) Fiber optic temperature sensors, which have the advantage of high test temperature but the disadvantages of being unable to achieve wireless measurement and the signal being easily interfered by environmental factors; (2) Metal-based temperature sensors: They have the advantages of mature technology and high temperature resistance, but the disadvantages of poor oxidation and corrosion resistance and being unable to achieve wireless passive measurement; (3) Ceramic-based temperature sensors: They have the advantages of high temperature resistance, oxidation resistance, and corrosion resistance, and good tolerance to high-temperature extreme environments, but the disadvantages of being difficult to process, especially the preparation process of small-size complex structures is difficult and costly.

[0003] Polymer precursor ceramics are a new type of ceramic material that converts liquid polymer precursors into ceramics through crosslinking curing and pyrolysis. The liquid precursors have the characteristics of fluidity, processability, structural designability, and easy formability. The ceramics formed after crosslinking curing and pyrolysis have good high-temperature thermal stability, excellent high-temperature multifunctionality, oxidation and corrosion resistance, etc. At the same time, the entire preparation process is simple and low-cost. Therefore, polymer precursor ceramics are high-quality candidate materials for solving the above-mentioned extreme environment sensors. There have been some reports on the research of polymer precursor ceramic temperature sensors. For example, the invention application with the application number CN201310416802.6 discloses a SiCN ceramic wireless passive temperature sensor and its preparation method, and the invention application with the application number CN201810009046.8 discloses a SiCN wireless passive temperature sensor loaded with a patch antenna and its preparation method. However, the above-mentioned research all applies a certain metal coating outside the polymer precursor ceramic to form a resonant cavity, and then realizes wireless passive temperature measurement. The disadvantage of this design is that the outer metal cannot be used for a long time in extreme environments such as strong oxidation and strong corrosion. At the same time, the quality factor (Q value) of this design is low, and the sensor size is large (>6 mm), which is not conducive to the development requirements of device miniaturization.

[0004] Ceramic-based dielectric metamaterials are usually formed by periodically arranged artificial atoms of dielectric ceramics. They achieve resonance by utilizing the coupling effects within and between the artificial atoms of dielectric ceramics, and have the characteristics of low inherent loss, flexible design of structure and size, and good weather resistance. The ceramic-based dielectric metasurface is a two-dimensional array plane composed of structural units of ceramic-based dielectric metamaterials. Compared with three-dimensional metamaterials, the metasurface has a thinner thickness, is easier to miniaturize and integrate, and can realize the regulation of electromagnetic waves more flexibly and precisely. Accordingly, we innovatively propose a high-temperature extreme environment temperature sensor based on a polymer precursor ceramic metasurface by utilizing the characteristics of the structural designability, easy small-size formability, and temperature sensitivity of polymer precursor ceramics, effectively solving the problems of traditional resonant wireless passive temperature sensors. The core points are as follows: (1) Regulation of the dielectric constant and dielectric loss of polymer precursor ceramics (a high dielectric constant can more effectively confine electromagnetic energy, and appropriate loss is more conducive to enhancing the interaction between electromagnetic waves and materials, which is beneficial to the miniaturization of devices); (2) How to solve the problems of difficult processing and preparation of micro-scale ceramic structures. Summary of the Invention

[0005] In order to solve the problems existing in the above-mentioned background technology, the present invention proposes a preparation method for a temperature sensor based on a polymer precursor ceramic metasurface, which has the characteristics of high temperature resistance, small volume, simple preparation process, high sensitivity, etc.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The temperature sensor based on the polymer precursor ceramic metasurface mainly includes three parts: a polymer precursor ceramic microstructure array, an intermediate dielectric layer, and a reflective layer (as Figure 1 shown), and the polymer precursor ceramic microstructure array and the intermediate dielectric layer are sequentially arranged on the reflective layer from top to bottom. It is characterized in that: the preparation method of the temperature sensor based on the polymer precursor ceramic metasurface includes the following steps:

[0008] 1) Prepare a polymer precursor ceramic sensitive material precursor mixture with adjustable dielectric constant and loss;

[0009] 2) Based on the polymer precursor (mixture) prepared in step 1), form a polymer precursor ceramic microstructure array on the intermediate dielectric layer (2) to form a metasurface (3);

[0010] 3) Prepare a reflective layer (1) on the lower surface of the intermediate dielectric layer (2), and the reflective layer (1) is a high-temperature resistant metal layer or a high-conductivity composite material layer (1) to obtain a polymer precursor ceramic metasurface temperature sensor.

[0011] The specific implementation manner of the above step 1) includes the following:

[0012] Method 1: Mechanical mixing method. Weigh an appropriate amount of ceramic powder with a high dielectric constant, and then weigh an appropriate amount of curing agent powder. Add the ceramic powder and the curing agent powder into an appropriate amount of liquid polymer precursor respectively, and heat and dissolve under the protection of inert gas to obtain a mixed solution;

[0013] Method 2: Chemical synthesis method. Weigh an appropriate amount of ceramic precursor and mix it with a suitable solvent and deionized water to obtain solution B. Under anhydrous and anaerobic conditions, weigh an appropriate amount of metal salt solution or metal salt with a high dielectric constant and dissolve it in a suitable solvent to obtain solution A. Inject the freshly prepared A into B, slowly drop in a catalyst, and then heat for a polycondensation reaction. Finally, remove the solvent to obtain a liquid polymer precursor solution containing a high dielectric phase. Weigh an appropriate amount of curing agent powder and add it to an appropriate amount of the liquid polymer precursor solution containing a high dielectric phase, and heat and dissolve under the protection of inert gas to obtain a mixed solution.

[0014] In step 1), the curing agent is a photo-curing agent or a thermal-curing agent. The photo-curing agent is (2,4,6-trimethylbenzoyl) phosphine oxide, and the thermal-curing agent is dicumyl peroxide; in step 1), the mass ratio of the liquid polymer precursor to the curing agent powder is 1:0.008 - 0.15; in step 1), the temperature during heating and dissolution is 80 - 200 °C; in method 1 of step 1), the liquid polymer precursor includes polysilazane, polyborosilazane, polyaluminosilazane or polyboronaluminosilazane; in method 1 of step 1), the ceramic powder with a high dielectric constant includes calcium titanate, strontium titanate, barium titanate or strontium barium titanate powder; in method 1 of step 1), the mass ratio of the liquid polymer precursor to the ceramic powder with a high dielectric constant is 1:0.05 - 0.95; in method 2 of step 1), the ceramic precursor is a polyalkoxysiloxane; in method 2 of step 1), the solvent for the polyalkoxysiloxane is anhydrous ethanol; in method 2 of step 1), the metal salt solution with a high dielectric constant includes zirconium n-propoxide, zirconium n-butoxide, zirconium acetylacetonate, titanium n-propoxide, tetraethyl titanate or tetrabutyl titanate, etc., and the metal salt is tantalum chloride, etc.; in method 2 of step 1), the solvent for the metal salt is anhydrous ethanol; in method 2 of step 1), the catalyst is high-purity hydrochloric acid; in method 2 of step 1), the molar ratio of the silicon content in the polyalkoxysiloxane to the metal content in the metal salt or metal salt solution is 1:0.2 - 1.2; in method 2 of step 1), the molar ratio of the alkoxy group in the polyalkoxysiloxane to the deionized water is 1:0.5 - 1.3; in method 2 of step 1), the dosage of the high-purity hydrochloric acid is such that the pH of the reaction solution is about 5; in method 2 of step 1), the heating temperature of the polycondensation reaction is 65 - 80 °C, and the reaction time of the polycondensation reaction is 6 - 15 h.

[0015] The preparation method of the polymer precursor ceramic microstructure array and the dielectric layer in step 2) is mold casting or direct lithography.

[0016] When the preparation method is mold casting, the specific implementation method of step 2) is as follows:

[0017] a.1) Pour the mixture obtained in step 1) into a mold with a pre-designed polyhedron groove microstructure, and then pour another layer of the mixture with a certain thickness above the groove.

[0018] a.2) After the mixture in the mold is cured, demold it to obtain the intermediate dielectric layer and the polymer precursor microstructure array at the same time. The polymer precursor microstructure array is stacked above the intermediate dielectric layer.

[0019] a.3) Perform high-temperature heat treatment on the obtained polymer precursor microstructure array and the intermediate dielectric layer in an inert atmosphere to obtain a polymer precursor ceramic metasurface.

[0020] When the preparation method is lithography, the specific implementation method of step 2) is as follows:

[0021] b.1) Coat the upper surface of the intermediate dielectric layer with the mixture obtained in step 1).

[0022] b.2) Use an ultraviolet lithography machine to perform lithography on the part of the intermediate dielectric layer coated with the mixture according to the designed template, and then use a cleaning solution to remove the excess mixture on the intermediate dielectric layer to obtain a solid polymer precursor microstructure array attached to the intermediate dielectric layer.

[0023] b.3) Perform high-temperature heat treatment on the obtained polymer precursor microstructure array and the intermediate dielectric layer in an inert atmosphere to obtain a polymer precursor ceramic metasurface.

[0024] The mold in step a.1) is a silicone mold; the silicone mold contains pre-designed grooves arranged in an array; the single microstructure of the groove is a cylinder, a cone, a cube, a tetrahedron, a hexahedron, a prism or a pyramid; the side length, diameter or height of the single microstructure of the groove is 0.5 μm - 1 mm; the side length or diameter of the entire array area is 0.5 mm - 30 mm.

[0025] The curing in step a.2) is carried out by ultraviolet curing or thermal curing; when the curing is carried out by ultraviolet curing, the exposure time of the curing is 200 ms - 30 min; when the curing is carried out by thermal curing, the curing temperature is 80 - 150 °C, and the curing time is 10 - 120 min.

[0026] The intermediate dielectric layer in step b.1) is a polymer precursor ceramic, alumina ceramic, zirconia ceramic or silica ceramic, and the thickness of the intermediate dielectric layer is 0.5 μm - 1 mm;

[0027] In step b.2), the side length, diameter or height of each microstructure is 0.5 μm - 500 μm, and the side length or diameter of the entire array area is 0.5 mm - 30 mm;

[0028] The cleaning liquid in step b.2) is isopropyl alcohol or ethanol.

[0029] The inert gas in steps a.3) and b.3) is nitrogen or argon, the temperature of the high-temperature pyrolysis is 800 - 1350 °C, and the pyrolysis time is 30 min - 360 min; the polymer precursor ceramic obtained after the high-temperature heat treatment is SiCN, SiBCN, SiAlCN or SiAlBCN, etc.

[0030] The specific implementation manner of step 3) is Method 1 or Method 2:

[0031] Method 1 is to directly deposit a high-temperature resistant metal layer on the lower surface of the intermediate dielectric layer, and the method of depositing the high-temperature resistant metal layer is evaporation plating, electroplating or magnetron sputtering.

[0032] Method 2 is to select a high-temperature resistant metal substrate or a high-conductivity composite material, and directly prepare the polymer precursor ceramic metasurface on the high-temperature resistant metal or high-conductivity composite material.

[0033] In Method 1 and Method 2, the high-temperature resistant metal layer or metal substrate is platinum, gold, tungsten, nickel alloy or tungsten molybdenum alloy, and the thickness range of the metal layer, metal substrate and high-conductivity composite material is 0.5 μm - 2 mm;

[0034] The advantages of the present invention are:

[0035] The present invention provides a temperature sensor based on a polymer precursor ceramic metasurface and a preparation method thereof. The method includes the following steps: 1) preparing a polymer precursor ceramic sensitive material precursor with adjustable dielectric constant and loss; 2) preparing a polymer precursor ceramic metasurface microstructure array and a dielectric layer; 3) preparing a high-temperature resistant metal or high-conductivity reflective layer. The present invention can be applied to the field of high-temperature extreme environments, and has the characteristics of high temperature resistance, small volume, simple preparation process, high sensitivity, wireless and passive, etc. The sensor has good universality and can be used in high-temperature extreme environments such as aeroengines, nuclear reactors, and thermal power plants. Description of the Drawings

[0036] Figure 1 It is a schematic structural composition diagram of a temperature sensor based on a polymer precursor ceramic metasurface of the present invention;

[0037] Wherein: 1 - reflective layer, 2 - intermediate dielectric layer, 3 - polymer precursor ceramic microstructure array.

[0038] Figure 2 It is a graph showing the relationship between the resonant peak and frequency at different temperatures in Example 1;

[0039] Figure 3 It is a linear relationship graph between the resonant frequency and temperature in Example 1;

[0040] Figure 4 It is a microscopic morphology graph of the polymer precursor ceramic microstructure array in Example 3.

[0041] Figure 5 It is a graph showing the relationship between the resonant intensity and resonant frequency at different temperatures in Example 4;

[0042] Figure 6 It is a linear relationship graph between the resonant frequency and temperature in Example 4;

[0043] Figure 7 It is a graph showing the relationship between the resonant intensity and resonant frequency at different temperatures in Example 8;

[0044] Figure 8 It is a linear relationship graph between the resonant frequency and temperature in Example 8;

[0045] Figure 9 It is a distribution graph of the electric field and magnetic field on the cross-sections (A, B, C, D) of four unit structures in Example 1. Detailed implementation manners

[0046] The present invention provides a temperature sensor based on a polymer precursor ceramic metasurface and a preparation method thereof. The temperature sensor based on the polymer precursor ceramic metasurface mainly includes three parts: a polymer precursor ceramic microstructure array, an intermediate dielectric layer, and a reflective layer (as Figure 1 shown). It is characterized in that the preparation method of the temperature sensor based on the polymer precursor ceramic metasurface includes the following steps:

[0047] 1) Prepare a polymer precursor ceramic sensitive material precursor mixture with adjustable dielectric constant and loss;

[0048] 2) Based on the polymer precursor (mixture) prepared in step 1), form a polymer precursor ceramic microstructure array on the intermediate dielectric layer (2) to form a metasurface (3);

[0049] 3) Prepare a high-temperature resistant metal layer or a highly conductive composite material layer (1) on the lower surface of the intermediate dielectric layer (2) to obtain a polymer precursor ceramic metasurface temperature sensor.

[0050] The specific implementation methods of step 1) include the following:

[0051] Method 1: Mechanical mixing method. Weigh an appropriate amount of ceramic powder with a high dielectric constant, and then weigh an appropriate amount of curing agent powder. Add the ceramic powder and the curing agent powder into an appropriate amount of liquid polymer precursor respectively, and heat and dissolve under the protection of inert gas to obtain a mixed solution;

[0052] Method 2: Chemical synthesis method. Weigh an appropriate amount of ceramic precursor and mix it with a suitable solvent and deionized water to obtain solution B. Weigh an appropriate amount of metal salt solution or metal salt with a high dielectric constant and dissolve it in a suitable solvent under anhydrous and anaerobic conditions to obtain solution A. Inject the freshly prepared A into B, slowly drop in a catalyst, and then heat for polycondensation reaction. Finally, remove the solvent to obtain a liquid polymer precursor solution containing a high dielectric phase. Weigh an appropriate amount of curing agent powder and add it into an appropriate amount of liquid polymer precursor solution containing a high dielectric phase, and heat and dissolve under the protection of inert gas to obtain a mixed solution.

[0053] In step 1), the curing agent is a photo-curing agent or a thermal-curing agent. The photo-curing agent is (2,4,6-trimethylbenzoyl) phosphine oxide, and the thermal-curing agent is dicumyl peroxide; in step 1), the mass ratio of the liquid polymer precursor to the curing agent powder is 1:0.008 - 0.15; in step 1), the temperature during heating and dissolution is 80 - 200 °C; in method 1 of step 1), the liquid polymer precursor includes polysilazane, polyborosilazane, polyaluminosilazane or polyboron-aluminosilazane; in method 1 of step 1), the ceramic powder with a high dielectric constant includes calcium titanate, strontium titanate, barium titanate or strontium barium titanate powder; in method 1 of step 1), the mass ratio of the liquid polymer precursor to the ceramic powder with a high dielectric constant is 1:0.05 - 0.95; in method 2 of step 1), the ceramic precursor is a polyalkoxysiloxane; in method 2 of step 1), the solvent of the polyalkoxysiloxane is anhydrous ethanol; in method 2 of step 1), the metal salt solution with a high dielectric constant includes zirconium propoxide, zirconium butoxide, zirconium acetylacetonate, titanium propoxide, tetraethyl titanate or tetrabutyl titanate, etc., and the metal salt is tantalum chloride, etc.; in method 2 of step 1), the solvent of the metal salt is anhydrous ethanol; in method 2 of step 1), the catalyst is high-purity hydrochloric acid; in method 2 of step 1), the molar ratio of the silicon content in the polyalkoxysiloxane to the metal content in the metal salt or metal salt solution is 1:0.2 - 1.2; in method 2 of step 1), the molar ratio of the alkoxy group in the polyalkoxysiloxane to deionized water is 1:0.5 - 1.3; in method 2 of step 1), the dosage of the high-purity hydrochloric acid is such that the pH of the reaction solution is about 5; in method 2 of step 1), the heating temperature of the polycondensation reaction is 65 - 80 °C, and the reaction time of the polycondensation reaction is 6 - 15 h.

[0054] In step 2), the preparation method of the polymer precursor ceramic metasurface microstructure array and the dielectric layer is mold casting molding or direct lithography molding.

[0055] When the preparation method is die-casting molding, the specific implementation method of step 2) is as follows:

[0056] a.1) Pour the mixture obtained in step 1) into a mold with a pre-designed polyhedron groove microstructure, and then pour another layer of the mixture with a certain thickness above the groove;

[0057] a.2) After the mixture in the mold is cured, demold it to obtain the intermediate dielectric layer and the polymer precursor microstructure array at the same time. The polymer precursor microstructure array is stacked above the intermediate dielectric layer;

[0058] a.3) Perform high-temperature heat treatment on the obtained polymer precursor microstructure array and the intermediate dielectric layer in an inert atmosphere to obtain a polymer precursor ceramic metasurface;

[0059] When the preparation method is lithography molding, the specific implementation method of step 2) is as follows:

[0060] b.1) Coat the upper surface of the intermediate dielectric layer with the mixture obtained in step 1);

[0061] b.2) Use an ultraviolet lithography machine to perform lithography on the part of the intermediate dielectric layer coated with the mixture according to the designed template, and then use a cleaning solution to remove the excess mixture on the intermediate dielectric layer to obtain a solid polymer precursor microstructure array attached to the intermediate dielectric layer.

[0062] b.3) Perform high-temperature heat treatment on the obtained polymer precursor microstructure array and the intermediate dielectric layer in an inert atmosphere to obtain a polymer precursor ceramic metasurface;

[0063] The mold in step a.1) is a silicone mold; the silicone mold contains grooves arranged in a pre-designed array; the single microstructure of the groove is a cylinder, a cone, a cube, a tetrahedron, a hexahedron, a prism or a pyramid; the side length, diameter or height of the single microstructure of the groove is 0.5 μm - 1 mm; the side length or diameter of the entire array area is 0.5 mm - 30 mm;

[0064] The curing in step a.2) is carried out by ultraviolet curing or thermal curing; when the curing is carried out by ultraviolet curing, the exposure time for curing is 200 ms - 30 min; when the curing is carried out by thermal curing, the curing temperature is 80 - 150 °C, and the curing time is 10 - 120 min;

[0065] The intermediate dielectric layer in step b.1) is polymer precursor ceramic, alumina ceramic, zirconia ceramic or silica ceramic, and the thickness of the intermediate dielectric layer is 0.5 μm - 1 mm;

[0066] In step b.2), the side length, diameter or height of each microstructure is 0.5 μm - 500 μm, and the side length or diameter of the entire array area is 0.5 mm - 30 mm;

[0067] The cleaning liquid in step b.2) is isopropyl alcohol or ethanol.

[0068] The inert gas in steps a.3) and b.3) is nitrogen or argon, the temperature of high-temperature pyrolysis is 800 - 1350 °C, and the pyrolysis time is 30 min - 360 min; The polymer precursor ceramics obtained after high-temperature heat treatment are SiCN, SiBCN, SiAlCN, SiAlBCN, etc.

[0069] The specific implementation method of step 3) is Method 1 or Method 2:

[0070] Method 1 is to directly deposit a high-temperature resistant metal layer on the lower surface of the intermediate dielectric layer, and the method of depositing the high-temperature resistant metal layer is evaporation plating, electroplating or magnetron sputtering.

[0071] Method 2 is to select a high-temperature resistant metal substrate or a high-conductivity composite material, and directly prepare the polymer precursor ceramic metasurface on the high-temperature resistant metal or high-conductivity composite material.

[0072] In Method 1 and Method 2, the high-temperature resistant metal layer or metal substrate is platinum, gold, tungsten, nickel alloy or tungsten molybdenum alloy, and the thickness range of the metal layer, metal substrate and high-conductivity composite material is 0.5 μm - 2 mm.

[0073] The technical solution of the present invention will be described in detail below in conjunction with the embodiments. At the same time, the following embodiments are only used to illustrate the present invention in detail and do not limit the scope of the present invention in any way.

[0074] Example 1:

[0075] (1) Weigh 4.5 g of calcium titanate powder, and then weigh 0.75 g of dicumyl peroxide powder. Add the calcium titanate powder and dicumyl peroxide powder to 5 g of liquid polysilazane respectively, and heat up to 80 °C under nitrogen gas protection to dissolve to obtain a mixed solution;

[0076] (2) Take an appropriate amount of the mixed solution prepared in step (1) and pour it into a pre-designed silicone mold with a cube groove microstructure. The length of the cube groove is 160 μm, the width is 160 μm, and the height is 160 μm. The center distance between two grooves is 550 μm. Then pour another layer of the mixed solution with a thickness of 13.4 μm above the grooves. Convert the liquid polysilazane into a solid state at a temperature of 150 °C, and then demold to obtain a polymer precursor intermediate medium layer with a thickness of 13.4 μm. The upper surface of the polymer precursor intermediate medium layer has an array structure of cubes with a length of 160 μm, a width of 160 μm, and a height of 160 μm. Place the prepared polymer precursor microstructure array and the intermediate medium layer into a high-temperature furnace and pyrolyze at a temperature of 1400 °C under the protection of argon to obtain a polymer precursor ceramic metasurface;

[0077] (3) Directly evaporate and deposit high-temperature-resistant metal platinum onto the lower surface of the intermediate medium layer prepared in step (2) to obtain a polymer precursor ceramic metasurface temperature sensor.

[0078] Example 2:

[0079] (1) Weigh 0.5 g of barium strontium titanate powder and then weigh 0.2 g of dicumyl peroxide powder. Add the barium strontium titanate powder and dicumyl peroxide powder into 10 g of liquid polyborosilazane respectively, and heat up to 150 °C under the protection of argon gas to dissolve and obtain a mixed solution;

[0080] (2) Take an appropriate amount of the mixed solution prepared in step (1) and pour it into a pre-designed silicone mold with a cuboid groove microstructure. The length of the cuboid groove is 73.3 μm, the width is 73.3 μm, and the height is 88.0 μm. The center distance between two grooves is 333 μm. Then pour another layer of the solution with a thickness of 13.4 μm above the grooves. Convert the liquid polyborosilazane into a solid state at a temperature of 80 °C, and then demold to obtain a polymer precursor intermediate medium layer with a thickness of 13.4 μm. The upper surface of the polymer precursor intermediate medium layer has an array structure of cuboids with a length of 73.3 μm, a width of 73.3 μm, and a height of 88.0 μm. Place the prepared polymer precursor microstructure array and the intermediate medium layer into a high-temperature furnace and pyrolyze at a temperature of 800 °C under the protection of nitrogen to obtain a polymer precursor ceramic metasurface;

[0081] (3) Directly magnetron sputter high-temperature-resistant metal gold onto the lower surface of the intermediate medium layer prepared in step (2) to obtain a polymer precursor ceramic metasurface temperature sensor.

[0082] Example 3:

[0083] (1) Weigh 10 g of barium titanate powder and then weigh 2 g of dicumyl peroxide powder. Add the barium titanate powder and dicumyl peroxide powder separately to 20 g of liquid polyaluminosilazane, and heat to 100 °C under argon gas protection to dissolve and obtain a mixed solution;

[0084] (2) Take an appropriate amount of the mixed solution prepared in step (1) and pour it into a pre-designed silicone mold with a cylindrical groove microstructure. The diameter of the cylindrical groove is 8 μm, the height is 8 μm, and the center distance between two grooves is 13.5 μm. Pour another layer of solution with a thickness of 1.83 μm above the groove. Convert the liquid polyaluminosilazane into a solid state at a temperature of 100 °C, and then demold to obtain a 1.83-μm-thick polymer precursor intermediate medium layer. The upper surface of the polymer precursor intermediate medium layer has an array structure of cylinders with a diameter of 8 μm and a height of 8 μm. Put the prepared polymer precursor microstructure array and the intermediate medium layer into a high-temperature furnace and pyrolyze at 1000 °C under argon protection to obtain a polymer precursor ceramic metasurface;

[0085] (3) Bond a high-temperature-resistant metal tungsten plate to the lower surface of the intermediate medium layer prepared in step (2) to obtain a polymer precursor ceramic metasurface temperature sensor.

[0086] Example 4:

[0087] (1) Weigh 9 g of strontium titanate powder and then weigh 0.96 g of dicumyl peroxide powder. Add the strontium titanate powder and dicumyl peroxide powder separately to 12 g of liquid polyboron aluminosilazane, and heat to 100 °C under argon gas protection to dissolve and obtain a mixed solution;

[0088] (2) Take an appropriate amount of the mixed solution prepared in step (1) and pour it into a pre-designed silicone mold with a cuboid groove microstructure. The length of the cuboid groove is 73.3 μm, the width is 73.3 μm, the height is 88.0 μm, and the center distance between two grooves is 333 μm. Pour another layer of solution with a thickness of 13.4 μm above the groove. Convert the liquid polyboron aluminosilazane into a solid state at a temperature of 120 °C, and then demold to obtain a 13.4-μm-thick polymer precursor intermediate medium layer. The upper surface of the polymer precursor intermediate medium layer has a cuboid array structure with a length of 73.3 μm, a width of 73.3 μm, and a height of 88.0 μm. Put the prepared polymer precursor microstructure array and the intermediate medium layer into a high-temperature furnace and pyrolyze at 1100 °C under argon protection to obtain a polymer precursor ceramic metasurface;

[0089] (3) Weld a high-temperature-resistant metal nickel alloy plate to the lower surface of the intermediate medium layer prepared in step (2) to obtain a polymer precursor ceramic metasurface temperature sensor.

[0090] Example 5:

[0091] (1) Weigh 9 g of strontium titanate powder and then weigh 0.96 g of (2,4,6-trimethylbenzoyl)phosphine oxide powder. Add the strontium titanate powder and (2,4,6-trimethylbenzoyl)phosphine oxide powder into 12 g of liquid polyboron aluminosilazane respectively, and heat to 100 °C under argon gas protection to dissolve and obtain a mixed solution;

[0092] (2) Take an appropriate amount of the mixed solution prepared in step (1) and pour it into a pre-designed silicone mold with a cylindrical groove microstructure. The diameter of the cylindrical groove is 8 μm, the height is 8 μm, and the center distance between two grooves is 8 μm. Then pour another layer of solution with a thickness of 2 μm above the grooves. Under the condition of ultraviolet light curing for 20 min, convert the liquid polyboron aluminosilazane into a solid state, and then demold to obtain a 2-μm-thick polymer precursor intermediate medium layer. The upper surface of the polymer precursor intermediate medium layer has an array structure of cylinders with a diameter of 8 μm and a height of 8 μm. Put the prepared polymer precursor microstructure array and the intermediate medium layer into a high-temperature furnace and pyrolyze at 1000 °C under the protection of argon to obtain a polymer precursor ceramic metasurface;

[0093] (3) Bond the highly conductive composite material to the lower surface of the intermediate medium layer prepared in step (2) to obtain a polymer precursor ceramic metasurface temperature sensor.

[0094] Example 6:

[0095] (1) Weigh 14.8 g of trimethoxyvinylsiloxane, 21 g of absolute ethanol and 5.4 g of deionized water into a three-necked flask, and mix and stir for 0.5 h under nitrogen atmosphere protection; Weigh 7.17 g of tantalum chloride and dissolve it in 5 g of absolute ethanol in an anhydrous and oxygen-free environment, quickly inject it into the three-necked flask, stir for 0.5 h and then slowly drop 0.0365 g of high-purity hydrochloric acid, and heat to 60 °C and stir for 12 h; Filter the obtained pre-precursor solution through a sand core and then perform rotary evaporation to obtain a tantalum-modified polysiloxane precursor solution; Weigh 0.7 g of dicumyl peroxide powder and add it to 7 g of liquid tantalum-modified polysiloxane, and heat to 100 °C under nitrogen gas protection to dissolve and obtain a mixed solution;

[0096] (2) Take an appropriate amount of the mixed solution prepared in step (1) and pour it into a silicone mold with a cube groove microstructure. The length of the cube groove is 78.0 μm, the width is 78.0 μm, and the height is 78.0 μm. The center distance between two grooves is 359.3 μm. Then pour another layer of solution with a thickness of 18.6 μm above the grooves. Convert the liquid tantalum-modified polysiloxane into a solid state at a temperature of 120 °C, and then demold to obtain a polymer precursor intermediate medium layer with a thickness of 18.6 μm. The upper surface of the polymer precursor intermediate medium layer has an array structure of cubes with a length of 78.0 μm, a width of 78.0 μm, and a height of 78.0 μm. Place the prepared polymer precursor microstructure array and the intermediate medium layer into a high-temperature furnace and pyrolyze at a temperature of 1200 °C under the protection of argon to obtain a polymer precursor ceramic metasurface;

[0097] (3) Directly magnetron sputter high-temperature resistant metal gold onto the lower surface of the intermediate medium layer prepared in step (2) to obtain a polymer precursor ceramic metasurface temperature sensor.

[0098] Example 7:

[0099] (1) Weigh 8 g of dimethoxyvinylsiloxane, 12 g of trimethoxysilane, 52.239 g of absolute ethanol, and 11.232 g of deionized water into a three-necked flask, and mix and stir for 0.5 h under the protection of a nitrogen atmosphere. Weigh 49.136 g of zirconium propoxide quickly and inject it into the three-necked flask in an anhydrous and oxygen-free environment. After stirring for 0.5 h, slowly drop 0.0657 g of high-purity hydrochloric acid, and heat to 60 °C and stir for 6 h. Filter the obtained pre-precursor solution through a sand core and then perform rotary evaporation to obtain a zirconium-modified polysiloxane precursor solution. Weigh 2.8 g of (2,4,6-trimethylbenzoyl)phosphine oxide powder, add the phosphine oxide powder to 5.0 g of liquid zirconium-modified polysiloxane, and heat to 125 °C under the protection of nitrogen gas to dissolve and obtain a mixed solution;

[0100] (2) Take an appropriate amount of the mixed solution prepared in step (1) and pour it into a silicone mold with a cylindrical groove microstructure. The diameter of the cylindrical groove is 12.0 μm, the height is 26.0 μm, and the center distance between two grooves is 38.67 μm. Then pour another layer of solution with a thickness of 36.2 μm above the grooves. Convert the liquid zirconium-modified polysiloxane into a solid state under the condition of ultraviolet light curing for 15 min, and then demold to obtain a polymer precursor intermediate medium layer with a thickness of 36.2 μm. The upper surface of the polymer precursor intermediate medium layer has an array structure with a diameter of 12.0 μm and a height of 26.0 μm. Place the prepared polymer precursor microstructure array and the intermediate medium layer into a high-temperature furnace and pyrolyze at a temperature of 1150 °C under the protection of argon to obtain a polymer precursor ceramic metasurface;

[0101] (3)Weld the high-temperature resistant metal tungsten-molybdenum alloy plate to the lower surface of the intermediate dielectric layer prepared in step (2) to obtain the polymer precursor ceramic metasurface temperature sensor.

[0102] Example 8:

[0103] (1) Weigh 14.8 g of trimethoxyvinylsiloxane, 30.3 g of absolute ethanol and 9 g of deionized water into a three-necked flask, mix and stir for 0.5 h under nitrogen atmosphere protection; weigh 22.811 g of tetraethyl titanate quickly and inject it into the three-necked flask in an anhydrous and oxygen-free environment. After stirring for 0.5 h, slowly drop 0.0365 g of high-purity hydrochloric acid, heat to 85 °C and stir for 15 h; filter the obtained pre-precursor solution through a sand core and then perform rotary evaporation to obtain a titanium-modified polysiloxane precursor solution; weigh 0.45 g of (2,4,6-trimethylbenzoyl)phosphine oxide powder, add the phosphine oxide powder to 3.0 g of liquid titanium-modified polysiloxane, and heat to 125 °C under nitrogen gas protection to dissolve to obtain a mixed solution;

[0104] (2) Spin-coat the titanium-modified polysiloxane precursor solution prepared in step (1) on a 0.1 mm thick alumina ceramic; import the pre-designed template into the ultraviolet lithography machine. The length of a single microstructure of the microstructure array is 733 μm, the width is 733 μm, and the period is 3.33 mm. Use the ultraviolet lithography machine to perform lithography on the part coated with the mixed solution on the alumina ceramic, and then remove the excess mixed solution on the alumina ceramic with isopropanol. The upper surface of the intermediate dielectric layer of the alumina ceramic has a microstructure array with a length of 733 μm, a width of 733 μm, a height of 733 μm, and a period of 3.33 mm; put the prepared polymer precursor microstructure array and the intermediate dielectric layer into a high-temperature furnace, and pyrolyze at 1350 °C under nitrogen protection to obtain the polymer precursor ceramic metasurface;

[0105] (3) Directly evaporate deposit the high-temperature resistant metal platinum on the lower surface of the intermediate dielectric layer prepared in step (2) to obtain the polymer precursor ceramic metasurface temperature sensor.

[0106] The structural composition schematic diagram of a temperature sensor based on a polymer precursor ceramic metasurface of the present invention is as Figure 1 shown, where: 1 is the reflection layer, 2 is the intermediate dielectric layer, and 3 is the polymer precursor ceramic microstructure array. The relationship between the resonance peak and frequency of the temperature sensor based on the polymer precursor ceramic metasurface obtained in Example 1 is as Figure 2As shown, it can be seen from the figure that the sensor undergoes electromagnetic resonance in the range of 0.14 - 0.22 THz, and the resonance intensity is very high, with an absorption rate close to 100%. At the same time, as the temperature increases from 25 °C to 1300 °C, the complex dielectric constant of the polymer precursor ceramic doped with calcium titanate increases from 41.5 to 49.9, and the resonance frequency of the metasurface sensor decreases accordingly, from 0.1978 THz to 0.1804 THz. The relationship between the resonance frequency and temperature obtained in Example 1 is as Figure 3 shown. It can be seen that the resonance frequency of the metasurface sensor decreases monotonically with the increase of temperature, and there is a one-to-one correspondence between the resonance frequency and temperature. Figure 4 Figure 4 is the microscopic morphology diagram of the polymer precursor ceramic microstructure array obtained in Example 3. It can be seen from the figure that the SiCN ceramic cylinders are arranged regularly and neatly, and there are no micro pores or micro cracks inside the material. The relationship diagram between the resonance intensity and resonance frequency at different temperatures in Example 4 is as Figure 5 shown, and its linear relationship diagram between the resonance frequency and temperature is as Figure 6 shown. It can be seen that the resonance frequency of the metasurface sensor decreases monotonically with the increase of temperature, and there is a one-to-one correspondence between the resonance frequency and temperature. The relationship diagram between the resonance intensity and resonance frequency at different temperatures in Example 8 is as Figure 7 shown, and its linear relationship diagram between the resonance frequency and temperature is as Figure 8 shown. Similarly, it can be seen that the resonance frequency of the metasurface sensor decreases monotonically with the increase of temperature, and there is a one-to-one correspondence between the resonance frequency and temperature. Figure 9 Figure 14 is the distribution diagrams of the electric field and magnetic field on the cross-sections (A, B, C, D) of the four unit structures in Example 1.

[0107] When the present invention studies the temperature sensor based on the polymer precursor ceramic metasurface, it is found that as the types and contents of the ceramic powders with high dielectric constants doped are different, and the types and contents of the metals with high dielectric constants during chemical modification are different, the values of the complex dielectric constant change (5 - 300), and the complex dielectric loss tangent changes (0.001 - 0.5). Therefore, the dielectric constant and dielectric loss tangent of the temperature sensor based on the polymer precursor ceramic metasurface of the present invention are designable, so as to meet the design requirements of different working bands.

[0108] When studying the temperature sensor based on the polymer precursor ceramic metasurface, it is found that as the size, spacing, and period of the polymer precursor ceramic microstructure array change, the resonant frequency of the metasurface sensor changes; as the material and thickness of the intermediate dielectric layer change, the resonant frequency of the metasurface sensor changes; as the material of the reflective layer changes, the resonant frequency of the metasurface sensor changes. Therefore, the polymer precursor ceramic metasurface temperature sensor of the present invention has structural designability and resonant frequency adjustable flexibility, so as to meet the sensor shape and size requirements in different working scenarios.

[0109] The temperature sensor based on the polymer precursor ceramic metasurface in the present invention has high sensitivity, up to 0.188 GHz / °C. The present invention can be applied to the field of high-temperature extreme environments, and has the characteristics of high temperature resistance, small volume, simple preparation process, high sensitivity, wireless passivity, etc. This sensor has good universality and can be used in high-temperature extreme environments such as aeroengines, nuclear reactors, and thermal power plants.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Other modifications or equivalent replacements made by those of ordinary skill in the art to the technical solutions of the present invention shall be covered by the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a temperature sensor based on a polymer precursor ceramic supersurface, characterized in that: The temperature sensor based on the polymer precursor ceramic metasurface comprises a polymer precursor ceramic microstructure array (3), an intermediate dielectric layer (2) and a reflective layer (1); the polymer precursor ceramic microstructure array (3) and the intermediate dielectric layer (2) are arranged on the reflective layer (1) in sequence from top to bottom; The preparation method of the temperature sensor based on the polymer precursor ceramic supersurface comprises the following steps: 1) Prepare a polymer precursor ceramic sensitive material precursor mixed solution with adjustable dielectric constant and loss; 2) forming a polymer precursor ceramic microstructure array on the intermediate dielectric layer (2) based on the polymer precursor mixed solution prepared in step 1) to form a super surface (3); 3) A reflective layer (1) is prepared on the lower surface of the intermediate dielectric layer (2), wherein the reflective layer (1) is a high temperature resistant metal layer or a high conductive composite material layer (1), thereby obtaining a temperature sensor based on a polymer precursor ceramic super surface.

2. The method for preparing a temperature sensor based on a polymer precursor ceramic supersurface according to claim 1, characterized in that: The step 1) is method 1 or method 2; When the step 1) is the first method, the step 1) is a mechanical mixing method, specifically: weighing an appropriate amount of ceramic powder with a high dielectric constant, and then weighing an appropriate amount of curing agent powder, respectively adding the ceramic powder and the curing agent powder to an appropriate amount of liquid polymer precursor, and heating and dissolving under the protection of an inert gas to obtain a mixed liquid; When the step 1) is the second method, the step 1) is a chemical synthesis method, specifically: weighing an appropriate amount of a ceramic precursor and mixing it with a suitable solvent and deionized water to obtain a solution B, weighing an appropriate amount of a metal salt solution with a high dielectric constant or a metal salt dissolved in a suitable solvent under anhydrous and oxygen-free conditions to obtain a solution A, injecting the freshly prepared A into B, slowly dripping a catalyst, heating it for a polycondensation reaction, and finally removing the solvent to obtain a liquid polymer precursor solution containing a high dielectric phase; weighing an appropriate amount of a curing agent powder and adding it to an appropriate amount of a liquid polymer precursor solution containing a high dielectric phase, heating it under the protection of an inert gas to dissolve it to obtain a mixed solution.

3. The method for preparing a temperature sensor based on a polymer precursor ceramic supersurface according to claim 2, characterized in that: When the step 1) is method 1, the liquid polymer precursor includes polysilazane, polyborosilazane, polyaluminosilazane or polyboroaluminosilazane; the ceramic powder with a high dielectric constant includes calcium titanate, strontium titanate, barium titanate or barium strontium titanate powder; the mass ratio of the liquid polymer precursor to the ceramic powder with a high dielectric constant is 1:0.05-0.95; the curing agent is a photocuring agent or a thermosetting agent, when the curing agent is a photocuring agent, the photocuring agent is (2,4,6-trimethylbenzoyl)phosphine oxide, when the curing agent is a thermosetting agent, the thermosetting agent is diisopropylbenzene peroxide; the mass ratio of the liquid polymer precursor to the curing agent powder is 1:0.008-0.15; the temperature during the heating and dissolving is 80-200°C.

4. The method for preparing a temperature sensor based on a polymer precursor ceramic supersurface according to claim 2, characterized in that: When the step 1) is the second method, the ceramic precursor is a polyalkoxysiloxane; the polyalkoxysiloxane solvent is anhydrous ethanol; the metal salt solution with a high dielectric constant is zirconium n-propoxide, zirconium n-butoxide, zirconium acetylacetonate, titanium n-propoxide, tetraethyl titanate or tetrabutyl titanate; the metal salt is tantalum chloride; the metal salt solvent is anhydrous ethanol; the catalyst is high-purity hydrochloric acid; in the second method of the step 1), the molar ratio of the silicon content in the polyalkoxysiloxane to the metal content in the metal salt or the metal salt solution is 1:0.2-1.2; the alkoxy group in the polyalkoxysiloxane is 0.1% to 0.1%; the metal salt solvent is anhydrous ethanol; the catalyst is high-purity hydrochloric acid; the molar ratio of the silicon content in the polyalkoxysiloxane to the metal content in the metal salt or the metal salt solution ... metal salt solvent is anhydrous ethanol; the catalyst is high-purity hydrochloric acid; the metal salt solvent is anhydrous ethanol; the catalyst is high-purity hydrochloric acid; the metal salt solvent is anhydrous ethanol; the catalyst is high-purity hydrochloric acid; the metal salt solvent is anhydrous ethanol; the catalyst is high-purity hydro The molar ratio of the liquid polymer precursor to water is 1:0.5-1.3; the amount of the high-purity hydrochloric acid is such that the pH of the reaction solution is 5; the heating temperature of the polycondensation reaction is 65-80°C, and the reaction time of the polycondensation reaction is 6-15h; the curing agent is a photocuring agent or a thermosetting agent, when the curing agent is a photocuring agent, the photocuring agent is (2,4,6-trimethylbenzoyl)phosphine oxide, when the curing agent is a thermosetting agent, the thermosetting agent is diisopropylbenzene peroxide; the mass ratio of the liquid polymer precursor to the curing agent powder is 1:0.008-0.15; the temperature during the heating and dissolving is 80-200°C.

5. The method for preparing a temperature sensor based on a polymer precursor ceramic supersurface according to claim 1, characterized in that: The preparation method of the polymer precursor ceramic microstructure array and the dielectric layer in step 2) is mold casting or direct photolithography.

6. The method for preparing a temperature sensor based on a polymer precursor ceramic supersurface according to claim 5, characterized in that: When the preparation method of the polymer precursor ceramic microstructure array and the dielectric layer in step 2) is mold casting, the specific implementation method of step 2) is: a.1) pouring the mixed solution prepared in step 1) into a pre-designed mold of a polyhedral groove microstructure, and pouring a layer of the mixed solution with a certain thickness above the groove; a.2) demoulding after the mixed liquid in the mold is solidified, and obtaining an intermediate dielectric layer and a polymer precursor microstructure array at the same time, wherein the polymer precursor microstructure array is superimposed on the intermediate dielectric layer; a.3) subjecting the obtained polymer precursor microstructure array and the intermediate dielectric layer to high temperature heat treatment under an inert atmosphere to obtain a polymer precursor ceramic supersurface.

7. The method for preparing a temperature sensor based on a polymer precursor ceramic supersurface according to claim 6, characterized in that: The mold in step a.1) is a silicone mold; the silicone mold contains pre-designed grooves arranged in an array; the individual microstructures of the grooves are cylinders, cones, cubes, tetrahedrons, hexahedrons, prisms or pyramids; the side length, diameter or height of the individual microstructures of the grooves is 0.5 μm-1 mm; the side length or diameter of the entire array area is 0.5 mm-30 mm; The curing in step a.2) is by UV curing or thermal curing; when the curing is by UV curing, the exposure time of the curing is 200ms-30min; when the curing is by thermal curing, the curing temperature is 80-150°C and the curing time is 10-120min; The inert gas in step a.3) is nitrogen or argon, the high temperature pyrolysis temperature is 800-1350°C, and the pyrolysis time is 30min-360min; the polymer precursor ceramic obtained after the high temperature heat treatment is SiCN, SiBCN, SiAlCN or SiAlBCN.

8. The method for preparing a temperature sensor based on a polymer precursor ceramic supersurface according to claim 5, characterized in that: When the preparation method of the polymer precursor ceramic microstructure array and the dielectric layer in step 2) is direct photolithography, the specific implementation method of step 2) is: b.1) coating the mixed solution prepared in step 1) on the upper surface of the intermediate dielectric layer; b.2) using an ultraviolet lithography machine to perform photolithography on the portion of the intermediate dielectric layer coated with the mixed liquid according to the designed template, and then using a cleaning liquid to remove excess mixed liquid on the intermediate dielectric layer to obtain a solid polymer precursor microstructure array attached to the intermediate dielectric layer; b.3) subjecting the obtained polymer precursor microstructure array and the intermediate dielectric layer to high-temperature heat treatment under an inert atmosphere to obtain a polymer precursor ceramic supersurface.

9. The method for preparing a temperature sensor based on a polymer precursor ceramic supersurface according to claim 8, characterized in that: The intermediate dielectric layer in step b.1) is a polymer precursor ceramic, alumina ceramic, zirconia ceramic or silicon oxide ceramic, and the thickness of the intermediate dielectric layer is 0.5 μm-1 mm; In step b.2), the side length, diameter or height of each microstructure is 0.5 μm-500 μm, and the side length or diameter of the entire array area is 0.5 mm-30 mm; The cleaning solution in step b.2) is isopropanol or ethanol; The inert gas in step b.3) is nitrogen or argon, the high temperature pyrolysis temperature is 800-1350°C, and the pyrolysis time is 30min-360min; the polymer precursor ceramic obtained after the high temperature heat treatment is SiCN, SiBCN, SiAlCN or SiAlBCN.

10. The method for preparing a temperature sensor based on a polymer precursor ceramic supersurface according to claim 1, characterized in that: The specific implementation method of step 3) is method 1 or method 2: The first method is to directly plate a high temperature resistant metal layer on the lower surface of the intermediate dielectric layer, and the method of plating the high temperature resistant metal layer is evaporation, electroplating or magnetron sputtering; The second method is to select a high temperature resistant metal substrate or a high conductive composite material, and directly prepare the polymer precursor ceramic super surface on the high temperature resistant metal or the high conductive composite material; In the first and second methods, the high temperature resistant metal layer or metal substrate is platinum, gold, tungsten, nickel alloy or tungsten-molybdenum alloy, and the thickness of the metal layer, metal substrate and high conductive composite material ranges from 0.5 μm to 2 mm.

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