A high-temperature reversible thermochromic smart material and its preparation method and application

Abstract

The invention discloses a high-temperature reversible thermochromic smart material and a preparation method and application thereof. The chemical formula of the high-temperature reversible thermochromic smart material is LaCr 1‑x Co x O3, x is the doping amount of Co, 0≤x≤0.2, the material is prepared by a solid phase method or a sol-gel method, and coordinated with an organic carrier, coated on a substrate and calcined to obtain a high-temperature reversible thermochromic smart material coating. Compared with the prior art, the coating of the present invention can be light green at room temperature, gradually change to dark brown as the temperature rises, and return to light green when the temperature drops to room temperature. The range of action is from room temperature to 700°C, and it has the characteristics of high temperature stability, wide color change temperature range, high recyclability, easy large-area preparation, clear color and temperature correspondence, etc. It can be used for thermal indication of surface temperature at high-temperature hot end components such as aviation engines, aerospace engines, aerospace nuclear reactors, industrial furnaces, and civil gas turbines.

Description

Technical Field

[0001] The present invention relates to the technical field of functional materials, and in particular to a high-temperature reversible thermochromic smart material and a preparation method and application thereof. Background Art

[0002] Reversible thermochromic materials are a type of material whose color and optical properties change with the ambient temperature. They have an intelligent temperature indication effect and have broad application prospects in thermal indication and other aspects. Faced with extreme environmental conditions such as high temperature, high pressure, high speed, and narrow space, traditional temperature detection technology is difficult to apply. It is crucial to use reversible thermochromic materials for high-precision non-contact temperature measurement at high temperatures.

[0003] In the field of intelligent temperature indication, high-temperature reversible thermochromic coatings can realize the surface temperature thermal indication of high-temperature hot-end components such as aircraft engines, aerospace engines, aerospace nuclear reactors, industrial furnaces, and civil gas turbines. For example, the temperature of high-temperature components in aircraft engine blades, combustion chambers, and nozzles generally exceeds 500°C. Using high-temperature reversible color-changing coatings to measure the surface temperature of high-temperature components of the engine rotating at high speed can obtain the temperature field distribution of the tested components, with an intuitive and vivid full-domain temperature field color display. It is almost impossible to obtain such a result using conventional measurement technology.

[0004] The thermochromic materials reported so far are mainly organic substances such as esters, benzenes, anilines, polydiacetylene, and vanadium oxides (VO2, V2O5, etc.), rare earth garnet structure oxides (Er3Ga5O 12 、Sm3Fe5O 12 ), MoO3, Bi2O3 and other inorganic metal compounds. Organic materials are brightly colored, but the color change temperature range is mainly between room temperature (RT) and 200°C. They have poor thermal stability and are easily decomposed at higher temperatures. Among inorganic materials, V2O5 and MoO3-based materials mainly change color below 300°C. Er3Ga5O reported by Liu et al. (Chem. Mater. 2019, 31, 1048-1056) 12 It can change color in the range of room temperature to 460°C, and the visible spectra at different temperatures almost completely overlap. The color change is small and the correspondence between color and temperature is not clear. Yuan et al. (J. Mater. Chem. C, 2022, 10, 11354) reported that the chromaticity parameter La*ab of Fe / Cr-(co)-doped α-Al2O3 can be fitted with a functional relationship with temperature change, but the function is nearly a horizontal straight line and the error is large, which limits its further application. Therefore, the development of a high-temperature reversible thermochromic smart material that can stably change color at high temperatures and has a clear correspondence between temperature change and color change is a technical problem that needs to be solved urgently in the current research field. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a high-temperature reversible thermochromic smart material with high temperature stability, wide color change temperature range, high recyclability, easy large-area preparation, and clear color and temperature correspondence, as well as a preparation method and application thereof.

[0006] The purpose of the present invention can be achieved by the following technical solution: a high-temperature reversible thermochromic smart material, the chemical structure of which is LaCr 1-x Co x O3, wherein x is the doping amount of Co, 0≤x≤0.2.

[0007] The invention also provides a method for preparing a high-temperature reversible thermochromic intelligent material, which is prepared by a solid phase method or a sol-gel method.

[0008] Furthermore, the solid phase method includes the following steps: mixing a lanthanum-containing compound, a chromium-containing compound, and a cobalt-containing compound, placing the obtained mixture and an organic solvent in a ball mill for ball milling to obtain a mixed slurry, drying the mixed slurry and pressing it into sheets to obtain block flakes, which are then calcined, and the obtained solid phase product is crushed to obtain a thermochromic smart material.

[0009] The ball milling method mainly relies on the extrusion and shear force between the grinding media in the ball mill to break the material. During the ball milling process, the mechanical energy of the ball milling media is transferred to the powder in different forms through the violent collision, extrusion and friction between the ball milling media and the ball milling media, and between the powder and the ball milling media and the wall of the ball mill. In the frequent collisions in this process, the large grains of the powder are transformed into small grains and continuously refined.

[0010] The solid phase method is to fully mix metal salts or metal oxides in a certain proportion, grind them and calcine them, and directly obtain powders through solid phase reaction, or crush them again to obtain powders. The solid phase reaction starts with the diffusion contact between the two reactant molecules, followed by chemical reactions to generate product molecules. The product molecules accumulate to a certain size, and the crystal nucleus of the product appears, thus completing the nucleation process. As the crystal nucleus grows, an independent crystal phase of the product appears after reaching a certain size, and the target product is gradually formed.

[0011] Further, the lanthanum-containing compound includes lanthanum oxide; the chromium-containing compound includes chromium oxide; the cobalt-containing compound includes cobalt oxide;

[0012] The organic solvent is any one of ethanol, ethylene glycol, n-butanol, and acetone, or a mixed solvent of at least several of them; the amount of the organic solvent added is 5%-20% of the total mass of the mixture of metal compounds

[0013] The drying temperature is 100-140°C and the drying time is 24-48h;

[0014] The calcination temperature is 800-1200° C., and the calcination time is 2-24 hours.

[0015] Furthermore, the sol-gel method includes the following steps: mixing lanthanum nitrate, chromium nitrate and cobalt nitrate, mixing the resulting mixture with a chelating agent and a dispersant, and magnetically stirring under water bath heating until a dark blue sol is formed; aging the sol and cooling it to room temperature, and then drying it to form a gel; and fully grinding the gel and calcining it to obtain a thermochromic smart material.

[0016] Furthermore, the metal nitrates (lanthanum nitrate, chromium nitrate, cobalt nitrate) are first dissolved in water at a molar ratio of 1:1 to form a mixed solution, and then a chelating agent and a dispersant are added. The chelating agent includes citric acid; the dispersant includes ethylene glycol; the molar ratio of citric acid to total metal nitrates is 1.5-2.5:1, and the molar ratio of ethylene glycol to citric acid is 1-1.5:1;

[0017] Ethylene glycol (CH2OH)2) is a straight molecular chain structure. The hydroxyl groups at both ends can act as ligands to coordinate with metal ions and can be used as a dispersant. Citric acid (C6H8O7) contains three carboxyl groups. The carboxylic acid groups are deprotonated. The carboxylate radicals formed can chelate with divalent and trivalent elements and have strong chelating ability. It is used as a chelating agent.

[0018] The drying temperature is 80-100° C., and the drying time is 24-48 hours; the calcination temperature is 700-900° C., and the calcination time is 2-4 hours.

[0019] The present invention also provides an application of a high-temperature reversible thermochromic smart material, wherein the thermochromic smart material and an organic carrier are uniformly ground to form a printing slurry, which is then coated on a substrate and calcined to form a coating.

[0020] Furthermore, the organic carrier is ethyl cellulose and terpineol; the weight ratio of ethyl cellulose to terpineol is 1:(20-30);

[0021] The coating method is multi-layer screen printing, preferably 4-6 layers, and after printing, it is placed in an oven at 80-150° C. for drying for 15-30 minutes, and then the next layer is printed; the calcination temperature is 1300-1400° C., and the calcination is 2-6 hours.

[0022] Furthermore, the substrate includes a high-temperature hot end component of an aircraft engine, a space engine, an aerospace nuclear reactor, an industrial furnace or a civil gas turbine; and the coating indicates the temperature on the surface of the high-temperature hot end component.

[0023] Furthermore, the method for indicating the temperature of the coating on the surface of the high-temperature hot end component is to construct a temperature-color coordinate mathematical model, comprising the following steps:

[0024] S1: Take optical photos of the coating surface color at different temperatures and use the image processing system to obtain its color coordinate value and determine the color position in the chromaticity diagram;

[0025] S2: Fit the functional relationship between the chromaticity value and the temperature in the coordinate system to obtain the corresponding mathematical model between the coating color and the temperature.

[0026] The above color coordinates select CIE xyY (x, y, Y), and the chromaticity diagram selects CIE 1931XYZ system; the optical photograph is obtained using D65 light source for illumination, the light source is perpendicular to the sample spreading surface, the preferred distance between the light source and the sample is 30-60 cm, the shooting angle is 10-15°, and the shooting distance is 10-20 cm; in order to ensure the consistency of the image, the camera position, sample surface and light source position are fixed.

[0027] The high-temperature reversible thermochromic smart material described in the above technical solution or the high-temperature reversible thermochromic smart material prepared by the preparation method of the above technical solution is used in the field of thermal indication of surface temperature at high-temperature hot end components such as aircraft engines, aerospace engines, aerospace nuclear reactors, industrial furnaces and civil gas turbines.

[0028] Compared with the existing process technology, the present invention has the following advantages:

[0029] 1. The high-temperature reversible thermochromic smart material of the present invention has a simple and stable structure, a wider temperature range, and more stable high-temperature reversible thermochromic performance. The coating of the present invention can be light green at room temperature, gradually change to dark brown as the temperature rises, and return to light green when the temperature drops to room temperature. The effective range is from room temperature to 700°C, and it has the characteristics of wide color change temperature range, high temperature stability, high recyclability, easy large-area preparation, and clear color and temperature correspondence. It can be used for thermal indication of surface temperature at high-temperature hot end components such as aircraft engines, aerospace engines, aerospace nuclear reactors, industrial furnaces, and civil gas turbines.

[0030] 2. The high-temperature reversible thermochromic smart material of the present invention is used as a coating, the process is simple and environmentally friendly, it is easy to prepare on a large scale, it can display different colors at different temperatures, it can be used for temperature identification indication or temperature detection, and the color change is reversible with temperature, so it can be used in a long-term cycle.

[0031] 3. The high-temperature reversible thermochromic smart material coating of the present invention can fit a corresponding functional relationship between the coating color and the coating temperature. Therefore, the surface temperature can be directly determined by obtaining the coating surface color. The temperature field distribution can be digitally represented by capturing the coating color, which has an intelligent temperature indication effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1This is a comparison chart of the color change of the high-temperature reversible thermochromic smart material coating prepared in Example 1 of the present invention as the temperature increases between RT-700°C.

[0033] Figure 2 The chromaticity value change of the high-temperature reversible thermochromic smart material coating prepared in Example 1 of the present invention between RT-700°C.

[0034] Figure 3 This is the fitting relationship between the change in chromaticity value and temperature of the high-temperature reversible thermochromic smart material coating prepared in Example 1 of the present invention between RT-700°C.

[0035] Figure 4 This is a comparison chart of the color change of the high-temperature reversible thermochromic smart material coating prepared in Example 2 of the present invention as the temperature increases between RT-700°C.

[0036] Figure 5 This is a comparison chart of the color change of the high-temperature reversible thermochromic smart material coating prepared in Example 3 of the present invention as the temperature increases between RT-700°C. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0039] Example 1

[0040] The preparation method and application of the high-temperature reversible thermochromic smart material coating provided in this embodiment include the following steps:

[0041] (1) Preparation of thermochromic materials

[0042] Step 1, weigh metal nitrates: La(NO)3·6H2O and Cr(NO)3·9H2O respectively, dissolve them in ultrapure water in a molar ratio of 1:1, and stir them magnetically to obtain a mixed solution. Then, citric acid and ethylene glycol are added to the mixed solution as a chelating agent and a dispersant, respectively, wherein the molar ratio of citric acid to total metal nitrates is 2:1, and the molar ratio of ethylene glycol to citric acid is 1.2:1. The mixture is heated in a water bath at 80°C and stirred magnetically until a dark blue sol is formed.

[0043] Step 2: After aging the sol for 30 minutes and cooling to room temperature, the sol is placed in an oven at 80° C. and dried for 24 hours to form a gel.

[0044] Step 3, after fully grinding the gel, transfer it to a crucible, put it into a muffle furnace, heat it to 800° C. and calcine it for 2 hours to obtain a thermochromic powder material.

[0045] (2) Preparation of coating

[0046] Step 4: Mix and grind the thermochromic powder material with an organic carrier (a mixture of ethyl cellulose and pinene alcohol in a weight ratio of 1:25) to form a printing paste; print the printing paste on the substrate by screen printing, put it in an oven at 100°C for 15 minutes after printing, and then print the next layer. After printing 5 layers, put the printed coating in a muffle furnace and calcine it at 1300°C for 5 hours to form a high-temperature reversible thermochromic smart material coating. (Screen printing only needs to print the printing paste on the surface, so the characteristics of this method itself determine that the coating is easy to prepare on a large area)

[0047] (3) Construction of temperature-color coordinate model

[0048] Step 5, placing the high-temperature reversible thermochromic smart material coating on the thermal control plate, taking optical photos of the coating surface color at different temperatures, and using an image processing system (Photoshop commercial software is used in this embodiment, and the RGB chromaticity value is obtained and then converted to obtain the color coordinate value) to obtain its CIE xyY color coordinate value (x, y, Y), and determine the color position in the chromaticity diagram;

[0049] Step 6, fitting the functional relationship between the chromaticity values ​​x, y and the temperature T in the coordinate system (using the least square method to perform a simple linear fit on the chromaticity values ​​x, y and T) to obtain the corresponding relationship between the coating color and the temperature.

[0050] Figure 1 This is a comparison chart of the color change of the high-temperature reversible thermochromic smart material coating prepared in this example between RT and 700°C as the temperature increases. The coating shows obvious temperature-dependent thermochromic phenomenon. As the temperature is heated from room temperature to 700°C, the coating gradually changes from light green to dark brown, and returns to light green when the temperature drops to room temperature. The coating changes color stably between RT and 700°C, without decomposition or other chemical reactions, which can prove its high-temperature stability. At the same time, when the temperature drops to room temperature, the color also returns to the state at room temperature. The color change process is reversible, which can prove its high recyclability.

[0051] Figure 2 The figure shows the change of the chromaticity value of the coating in this embodiment between RT and 700°C. The figure clearly shows that the position of the coating color in the chromaticity diagram changes with the increase of temperature.

[0052] Figure 3 This is the fitting relationship between the chromaticity value change and temperature of the coating in this embodiment between RT-700℃. It can be seen that the values ​​of the color coordinates x, y of the coating color change linearly with the increase of temperature. The fitting relationship is T=19079.6x-6081.8, T=-13472.5y+5517.4. The coating surface temperature can be determined simply and directly through this relationship by obtaining the chromaticity value extracted by the coating surface color.

[0053] Example 2

[0054] The preparation method and application of the high-temperature reversible thermochromic smart material coating provided in this embodiment include the following steps:

[0055] (1) Preparation of thermochromic materials

[0056] Step 1, weighing metal nitrates La(NO)3·6H2O, Cr(NO)3·9H2O and Co(NO)2·6H2O respectively in a molar ratio of 1:0.95:0.05 and dissolving them in ultrapure water, magnetically stirring to obtain a mixed aqueous solution, and then adding citric acid and ethylene glycol as a chelating agent and a dispersant to the mixed solution, respectively, the molar ratio of citric acid to total metal nitrates is 1.5:1, and the molar ratio of ethylene glycol to citric acid is 1:1, and magnetically stirring is performed under heating at 80° C. in a water bath until a dark blue sol is formed.

[0057] Step 2: After aging the sol for 30 minutes and cooling to room temperature, the sol is placed in an oven at 80° C. and dried for 24 hours to form a gel.

[0058] Step 3, after fully grinding the gel, transfer it to a crucible, put it into a muffle furnace, heat it to 800° C. and calcine it for 2 hours to obtain a thermochromic powder material.

[0059] (2) Preparation of coating

[0060] Step 4, the thermochromic powder material and the organic carrier (a mixture of ethyl cellulose and pinene alcohol in a weight ratio of 1:20) are mixed and ground to form a printing slurry; the mixed slurry is printed on the substrate by screen printing, and after printing, it is placed in an oven at 100°C for drying for 15 minutes and then the next layer is printed. Five layers are printed in this way, and the printed coating is then placed in a muffle furnace and calcined at 1300°C for 5 hours to form a high-temperature reversible thermochromic smart material coating.

[0061] (3) Construction of temperature-color coordinate model

[0062] Step 5, placing the high-temperature thermochromic coating on the thermal control plate, taking optical photos of the coating surface color at different temperatures and using an image processing system to obtain its CIE xyY color coordinate value (x, y, Y), and determining the color position in the chromaticity diagram;

[0063] Step 6, fitting the functional relationship between the chromaticity values ​​x, y and the temperature T in the coordinate system to obtain the corresponding relationship between the coating color and the temperature.

[0064] Example 3

[0065] The preparation method and application of the high-temperature reversible thermochromic smart material coating provided in this embodiment include the following steps:

[0066] (1) Preparation of thermochromic materials

[0067] Step 1, weigh the metal oxides La2O3, Cr2O3 and CoO respectively and mix them in a molar ratio of 1:0.85:0.15, then put the mixture and ethanol (the amount of ethanol added is 5% of the total mass of the mixture) into a ball mill for ball milling to obtain a mixed slurry.

[0068] Step 2: Place the mixed slurry in an oven at 120° C. and dry for 24 hours, then use a tablet press to press the solid phase to obtain a thin sheet material.

[0069] Step 3, putting the thin sheet material into a crucible, placing it in a muffle furnace and calcining it at 1200° C. for 12 hours, and fully grinding the calcined solid phase product in a mortar to obtain a thermochromic powder material.

[0070] (2) Preparation of coating

[0071] Step 4, the thermochromic material powder and the organic carrier (a mixture of ethyl cellulose and pinene alcohol in a weight ratio of 1:30) are mixed and ground to form a printing slurry; the mixed slurry is then printed on the substrate by screen printing, and after printing, it is placed in an oven at 100°C for 15 minutes and then the next layer is printed, and 5 layers are printed in this way; the printed coating is then placed in a muffle furnace and calcined at 1300°C for 5 hours to form a high-temperature reversible thermochromic smart material coating.

[0072] (3) Construction of temperature-color coordinate model

[0073] Step 5, place the high temperature thermochromic coating on the thermal control plate and take optical photos of the coating surface color at different temperatures, such as Figure 4 As shown, the CIE xyY color coordinate value (x, y, Y) is obtained by using the image processing system to determine the color position in the chromaticity diagram;

[0074] Step 6, fitting the functional relationship between the chromaticity values ​​x, y and the temperature T in the coordinate system to obtain the corresponding relationship between the coating color and the temperature.

[0075] Example 4

[0076] The preparation method and application of the high-temperature reversible thermochromic smart material coating provided in this embodiment include the following steps:

[0077] (1) Preparation of thermochromic materials

[0078] Step 1, weigh the metal oxides La2O3, Cr2O3 and CoO respectively and mix them in a molar ratio of 1:0.95:0.05, then put the mixture and ethanol (the amount of ethanol added is 20% of the total mass of the mixture) into a ball mill for ball milling to obtain a mixed slurry.

[0079] Step 2: Place the mixed slurry in an oven at 120° C. and dry for 24 hours, then use a tablet press to press the solid phase to obtain a thin sheet material.

[0080] Step 3, putting the thin sheet material into a crucible, placing it in a muffle furnace and calcining it at 1200° C. for 12 hours, and fully grinding the calcined solid phase product in a mortar to obtain a thermochromic powder material.

[0081] (2) Preparation of coating

[0082] Step 4, the thermochromic material powder and the organic carrier (a mixture of ethyl cellulose and pinene alcohol in a weight ratio of 1:25) are mixed and ground to form a printing slurry; the mixed slurry is then printed on the substrate by screen printing, and after printing, it is placed in an oven at 100°C for 15 minutes and then the next layer is printed, and 5 layers are printed in this way; the printed coating is then placed in a muffle furnace and calcined at 1300°C for 5 hours to form a high-temperature reversible thermochromic smart material coating.

[0083] (3) Construction of temperature-color coordinate model

[0084] Step 5, placing the high-temperature thermochromic coating on the thermal control plate, taking optical photos of the coating surface color at different temperatures and using an image processing system to obtain its CIE xyY color coordinate value (x, y, Y), and determining the color position in the chromaticity diagram;

[0085] Step 6, fitting the functional relationship between the chromaticity values ​​x, y and the temperature T in the coordinate system to obtain the corresponding relationship between the coating color and the temperature.

[0086] Obviously, the above embodiments are only preferred implementation examples of the present invention, and are not intended to limit the implementation methods. For those skilled in the art, other improvements and modifications in different forms can be made on this basis. It is not necessary and impossible to list all the implementation methods here. However, the obvious improvements and modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. Application of a high-temperature reversible thermochromic smart material, characterized in that: The chemical structural formula of the high-temperature reversible thermochromic intelligent material is LaCr 1-x Co x O3, where x is the doping amount of Co, 0 < x ≤ 0.2; the high-temperature reversible thermochromic intelligent material is evenly ground with an organic carrier to form a printing paste, which is coated on a substrate and calcined to form a coating.

2. The application of the high-temperature reversible thermochromic smart material according to claim 1, characterized in that: The high-temperature reversible thermochromic smart material is prepared by a solid phase method or a sol-gel method.

3. The application of the high-temperature reversible thermochromic smart material according to claim 2, characterized in that: The solid phase method comprises the following steps: mixing a lanthanum-containing compound, a chromium-containing compound and a cobalt-containing compound, placing the obtained mixture and an organic solvent in a ball mill for ball milling to obtain a mixed slurry, drying the mixed slurry and then pressing it into sheets to obtain block flakes, which are then calcined, and the obtained solid phase product is crushed to obtain a thermochromic smart material.

4. The use of the high-temperature reversible thermochromic smart material according to claim 3, characterized in that: The lanthanum-containing compound includes lanthanum oxide; the chromium-containing compound includes chromium oxide; the cobalt-containing compound includes cobalt oxide; The organic solvent is any one of ethanol, ethylene glycol, n-butanol, and acetone, or a mixed solvent of at least several of them; the amount of the organic solvent added is 5%-20% of the total mass of the mixture of metal compounds; The drying temperature is 100-140°C and the drying time is 24-48h; The calcination temperature is 800-1200° C., and the calcination time is 2-24 hours.

5. The use of the high-temperature reversible thermochromic smart material according to claim 2, characterized in that: The sol-gel method comprises the following steps: mixing lanthanum nitrate, chromium nitrate and cobalt nitrate, mixing the obtained mixture with a chelating agent and a dispersant, and magnetically stirring under water bath heating until a dark blue sol is formed; aging the sol and cooling it to room temperature, and then drying it to form a gel; and fully grinding the gel and calcining it to obtain a thermochromic smart material.

6. The use of the high-temperature reversible thermochromic smart material according to claim 5, characterized in that: The chelating agent includes citric acid; the dispersant includes ethylene glycol; the molar ratio of citric acid to total metal nitrate is 1.5-2.5:1, and the molar ratio of ethylene glycol to citric acid is 1-1.5:1; The drying temperature is 80-100° C., and the drying time is 24-48 hours; the calcination temperature is 700-900° C., and the calcination time is 2-4 hours.

7. The use of the high-temperature reversible thermochromic smart material according to claim 1, characterized in that: The organic carrier is ethyl cellulose and terpineol; the weight ratio of ethyl cellulose to terpineol is 1:(20-30); The coating method is multi-layer screen printing, and after printing, it is placed in an oven at 80-150° C. for drying for 15-30 minutes, and then the next layer is printed; the calcination temperature is 1300-1400° C., and the calcination is 2-6 hours.

8. The application of the high-temperature reversible thermochromic smart material according to claim 1, characterized in that: The substrate includes a high-temperature hot end component of an aircraft engine, a space engine, an aerospace nuclear reactor, an industrial furnace or a civil gas turbine; the coating indicates the temperature on the surface of the high-temperature hot end component.

9. The use of the high-temperature reversible thermochromic smart material according to claim 8, characterized in that: The method for indicating the temperature of the coating on the surface of the high-temperature hot end component is to construct a temperature-color coordinate mathematical model, comprising the following steps: S1: Take optical photos of the coating surface color at different temperatures and use the image processing system to obtain its color coordinate value and determine the color position in the chromaticity diagram; S2: Fit the functional relationship between the chromaticity value and the temperature in the coordinate system to obtain the corresponding mathematical model between the coating color and the temperature.

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