A samarium-doped high-entropy garnet structure aluminate ceramic material, a preparation method and application thereof

Abstract

The application provides a samarium-doped high-entropy garnet structure aluminate ceramic material and a preparation method and application thereof, and has a chemical structure general formula of Re 3‑x Sm x Al5O 12 wherein Re includes at least five trivalent rare earth elements, Sm is a doping ion with a valence of +3, and x is less than 0.2. In addition, the preparation method is simple and easy to realize, and the characteristic of the preparation method is that the reaction sintering time of the material at high temperature is short, a large amount of energy consumed due to long-time maintenance of a high temperature field can be saved, and the maintenance time of the thermal field is also very short in the application preparation process of the thermal barrier coating, so that the preparation method of the in-situ rapid reaction sintering is very close to the conditions of industrial preparation, the properties of the thermal barrier coating material prepared by the method are more similar to those in actual production, and the in-situ reaction sintering can make the samarium-doped high-entropy garnet structure aluminate ceramic obtain high density and high quantum efficiency.

Description

Technical Field

[0001] This invention relates to the fields of thermal barrier coating materials and fluorescence temperature sensing technology, specifically to a samarium-doped high-entropy garnet structure aluminate ceramic material, its preparation method, and its applications. Background Technology

[0002] Thermal barrier coatings (TBCs) are inorganic protective coatings that act as thermal shielding between high-temperature combustion gases and the alloy component substrate, reducing the surface temperature of turbine blades in high-temperature environments. Numerous studies have shown that TBC technology can significantly improve engine thrust, extend engine life, reduce engine fuel consumption, enhance engine corrosion resistance, and improve engine efficiency, making it one of the core technologies of aero-engines. Modern aero-engines are evolving towards higher thrust-to-weight ratios and higher turbine inlet temperatures, meaning that hot-end components need to operate for extended periods in harsher and more demanding high-temperature and high-pressure environments, which places even stricter requirements on the thermal protection performance of TBC materials.

[0003] Currently, the most widely used thermal barrier coating ceramic material is yttrium-stabilized zirconia (YSZ). Its application structure consists of four parts: an alloy matrix, an MCrAlY or Pt-modified aluminide binder layer, a thermally grown oxide layer (TGO), and a YSZ ceramic layer. However, YSZ ceramic materials have several shortcomings: phase transformation at high temperatures easily causes cracks in the coating; poor sintering resistance, with high temperatures causing coating caking and reducing thermal conductivity; and poor resistance to oxidation and calcium magnesium aluminum silicon molten salt (CMAS) corrosion, leading to coating instability and failure. Therefore, traditional YSZ ceramic materials are insufficient to meet the performance requirements of advanced aero-engines, necessitating the development of new thermal barrier coating materials. Garnet aluminate materials possess excellent high-temperature stability, low thermal conductivity, a coefficient of thermal expansion very close to that of thermally grown alumina (TGO), and excellent high-temperature chemical compatibility, resulting in a tighter bond between the garnet aluminate ceramic surface layer and the binder layer. Furthermore, high-entropy garnet aluminate materials possess unique properties of high-entropy materials, such as lower thermal conductivity, stronger resistance to sintering and corrosion, and good high-temperature stability. These properties make high-entropy garnet aluminate materials a very promising thermal barrier coating material.

[0004] On turbine blades of aero-engines, the operational status of the surface thermal protection ceramic layer and TGO layer requires real-time and accurate assessment, especially the operating temperature of the functional layers. Currently, the most widely used method in temperature measurement is contact resistance thermometry, which has significant limitations in harsh environments such as strong corrosion, strong electromagnetic fields, and high pressure, and is difficult to miniaturize. Fluorescent temperature sensing, on the other hand, is a non-contact optical sensing method. Thanks to the development of fiber optic transmission technology, fluorescent temperature sensing has strong resistance to high voltage and electromagnetic interference, and high sensitivity. However, the thermal quenching of fluorescent materials limits the detection temperature range of current fluorescent temperature sensing, and few fluorescent materials can reach the high-temperature range. This results in a significant gap in high-temperature fluorescent temperature sensing, necessitating researchers to develop fluorescent materials for fluorescent temperature sensing that are resistant to thermal quenching and possess good fluorescence performance. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings of the prior art and provide a samarium-doped high-entropy garnet structure aluminate ceramic material, its preparation method, and its application.

[0006] To achieve the above-mentioned objectives, in a first aspect, the present invention provides a samarium-doped high-entropy garnet-structured aluminate ceramic material with the general chemical formula Re. 3-x Sm x Al5O 12 Among them, Re includes at least 5 trivalent rare earth elements, Sm is a dopant ion with a valence state of +3 and x < 0.2.

[0007] In one embodiment, rare earth elements include Y, Sc, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.

[0008] In one embodiment, the samarium-doped high-entropy garnet-structured aluminate ceramic material has a density of not less than 93%, a thermal conductivity of not more than 4 W / m Kelvin at 300–1200 degrees Celsius, and a coefficient of thermal expansion of not less than 8.5 × 10⁻⁶. -6 Every Kelvin.

[0009] In one embodiment, a samarium-doped high-entropy garnet-structured aluminate ceramic material emits Sm under 405 nm ultraviolet light excitation. 3+ The characteristic linear emission spectrum of the ions has a main emission wavelength of 617 nm and a quantum efficiency of not less than 30%. By comparing the fluorescence intensity ratio of different emission peak wavelengths, it can perform temperature self-checking at high temperatures. The maximum operating temperature of its fluorescence temperature sensing is not less than 300 degrees Celsius.

[0010] Secondly, the present invention provides a method for preparing a samarium-doped high-entropy garnet-structured aluminate ceramic material, comprising:

[0011] Weigh alumina, samarium oxide and at least five rare earth oxide powder raw materials according to stoichiometric ratio, and add them together with dispersant, dispersion medium and ball mill. After ball milling and drying, a fine and uniformly mixed powder raw material is obtained.

[0012] The powder raw material is successively ground, sieved, dry pressed, debinded, and cold isostatic pressed to obtain a ceramic green body;

[0013] High-temperature in-situ rapid reaction sintering of ceramic green bodies in a vacuum Joule furnace yields samarium-doped high-entropy garnet-structured aluminate ceramic materials.

[0014] In one embodiment, the dispersant is polyethylene glycol, the dispersion medium is alcohol or isopropanol, the ball mill is alumina, the ball milling speed is 200-450 rpm, the ball milling time is 5-36 hours, the drying temperature is 60-120 degrees Celsius, and the drying time is 12-24 hours.

[0015] In one embodiment, grinding is done manually for 10–30 minutes; sieving is performed using 180-mesh and 300-mesh sieves sequentially; dry pressing is achieved using carbide die molds with diameters of 10 mm, 15 mm, and 18 mm, with a pressure of 10–50 kN and a holding time of 2–5 minutes; the discharge temperature is 500–800 degrees Celsius, and the discharge time is 3–8 hours; cold isostatic pressing is performed in a cold isostatic press with a pressure of 180–250 MPa and a holding time of 60–300 seconds.

[0016] In one embodiment, the sintering temperature is 1500–1700 degrees Celsius, and the sintering time is 20–60 seconds.

[0017] In one embodiment, the amount of dispersant added is 2% of the total mass of alumina, samarium oxide and at least five rare earth oxide powder raw materials; the amount of dispersion medium added is 1.5 times the total mass of alumina, samarium oxide and at least five rare earth oxide powder raw materials; and the ball milling powder is added in a ball-to-material ratio of 1:10.

[0018] Thirdly, this invention provides an application of samarium-doped high-entropy garnet structure aluminate ceramic materials in the field of thermal barrier coatings.

[0019] The advantages and beneficial effects of this invention compared to the prior art are as follows:

[0020] (1) Currently, YSZ ceramic materials, the most widely used thermal barrier coating material, have many shortcomings that prevent them from meeting the requirements of advanced aero-engines. For example, phase transformation at high temperatures can easily cause cracks in the coating; poor sintering resistance leads to coating caking and reduced thermal conductivity at high temperatures; and poor resistance to oxidation and CMAS corrosion can cause coating instability and failure. Furthermore, the harsh working environment of thermal barrier coatings has created a significant gap in temperature detection methods, especially for fluorescent temperature sensing, which is rarely used in temperature ranges above 800 Kelvin. Therefore, developing and applying fluorescent temperature sensing technology in high-temperature regions is of great significance. The samarium-doped high-entropy garnet structure aluminate ceramic material and its preparation method provided in this invention can provide effective thermal protection for aero-engines while enabling self-temperature detection in a high-temperature range via fluorescent sensing.

[0021] (2) The present invention provides a method for preparing samarium-doped high-entropy garnet structure aluminate ceramic material, namely, using a raw material ball milling method to obtain a uniformly mixed and refined raw material, then using a pressure method to obtain a dense raw material green body, and then using a pulse Joule heating rapid reaction sintering method to obtain a dense samarium-doped high-entropy garnet structure aluminate ceramic material. This preparation method employs pulsed Joule heating rapid reaction sintering to prepare samarium-doped high-entropy garnet-structured aluminate ceramics in situ. The preparation process is simple and easy to implement. A key characteristic of this method is the short reaction sintering time at high temperatures, which saves significant energy compared to maintaining a high temperature field for extended periods. Furthermore, the thermal barrier coating application requires only a very short thermal field maintenance time. This in-situ rapid reaction sintering method closely resembles industrial preparation conditions, resulting in thermal barrier coatings with properties more similar to those used in actual production. In addition, in-situ reaction sintering enables samarium-doped high-entropy garnet-structured aluminate ceramics to achieve high density and high quantum efficiency, with a density greater than 93%, a thermal conductivity of no more than 4 W / m Kelvin at 300–1200°C, and a coefficient of thermal expansion of no less than 8.5 × 10⁻⁶. -6 Every Kelvin. Attached Figure Description

[0022] Figure 1 The (Y) prepared in Example 1 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12 Ceramic material and its XRD pattern after being treated at 1600 degrees Celsius.

[0023] Figure 2 This is the emission spectrum of a samarium-doped high-entropy garnet-structured aluminate ceramic material under 405 nm violet light excitation at different samarium doping concentrations.

[0024] Figure 3 To implement the (Y) obtained in step 1 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12 Emission spectrum of ceramic materials excited by 405 nm violet light.

[0025] Figure 4 To implement the (Y) obtained in step 1 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12 Excitation spectrum of ceramic materials under 617 nm monitoring.

[0026] Figure 5 The (Y) prepared in Example 1 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12 Temperature-varying spectra of ceramic materials excited by 405 nm violet laser light from 573 Kelvin to 1273 Kelvin.

[0027] Figure 6 The (Y) obtained in Example 1 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12 The variation of fluorescence intensity ratio at different wavelengths in ceramic materials with temperature and the fitted curve.

[0028] Figure 7 The (Y) obtained in Example 1 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O12 Surface morphology of ceramic materials after CMAS etching at 1350 degrees Celsius: (a) after 6 hours of etching; (b) after 12 hours of etching; (c) after 18 hours of etching.

[0029] Figure 8 The (Y) obtained in Example 1 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12 Images of ceramic materials in different sizes and specifications.

[0030] Figure 9 The (Y) obtained in Example 1 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12 Grain morphology of ceramic materials observed after being kept at 1550 degrees Celsius for a certain period of time: (a) 0 hours of holding; (b) 6 hours of holding; (c) 12 hours of holding; (d) 18 hours of holding.

[0031] Figure 10 The (Y) obtained in Example 1 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12 The average grain size change of salt ceramic material after being held at 1550 degrees Celsius for different times. Detailed Implementation

[0032] To make the technical problem to be solved, the technical solution, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0033] The purpose of this invention is to propose a samarium-doped high-entropy garnet structure aluminate ceramic material, its preparation method, and its application. This aims to address the problems of poor high-temperature phase stability and poor corrosion and sintering resistance of traditional YSZ ceramics, providing better thermal protection for turbine blades of high-performance aero-engines. Simultaneously, by utilizing the material's inherent fluorescence properties and combining them with fiber optic transmission technology to analyze its fluorescence information, self-sensing of the thermal barrier coating's temperature state in high-temperature regions can be achieved, addressing the material and technological gap in non-destructive temperature detection of turbine engine thermal barrier coatings.

[0034] In a first aspect, the present invention provides a samarium-doped high-entropy garnet-structured aluminate ceramic material with the general chemical formula Re. 3-x Sm x Al5O 12 Among them, Re includes at least 5 trivalent rare earth elements, Sm is a dopant ion with a valence state of +3 and x < 0.2.

[0035] Among the aforementioned technical solutions, high-entropy materials have rapidly become a research hotspot in various fields due to their four unique effects: thermodynamic high-entropy effect, kinetic hysteresis diffusion effect, structural lattice distortion, and performance "cocktail" effect. Thermodynamically, the high-entropy effect brought about by multiple elements enhances the formation of the solid solution phase, giving high-entropy garnet-structured aluminate materials excellent high-temperature stability. Kinetically, the differences in atomic size and asymmetric bonding and electronic structure caused by multiple atoms in the lattice lead to severe lattice distortion, which enhances phonon scattering, resulting in lower thermal conductivity in high-entropy garnet-structured aluminate materials. Kinetically, the large fluctuations in lattice potential energy between lattice sites hinder atomic diffusion, making atomic diffusion within high-entropy materials extremely slow. This gives high-entropy garnet-structured aluminate materials stronger resistance to sintering and corrosion. Therefore, high-entropy garnet-structured aluminate materials are highly suitable as thermal barrier coating materials.

[0036] In the structural formula, Sm 3+ Samarium doping, acting as a luminescent center, enables high-entropy garnet aluminates to absorb ultraviolet or violet light and emit orange-red light. Furthermore, Sm... 3+ It emits light through the ff transition, and the emission spectrum is a line spectrum. Therefore, the processing of light information is more accurate, resulting in smaller detection errors. At the same time, samarium-doped high-entropy garnet aluminate has strong resistance to thermal quenching, which allows it to maintain a certain luminescence intensity at high temperatures, thereby enabling higher detection temperatures.

[0037] The above technical solution utilizes the relationship between the fluorescence intensity ratio of two emission peaks at different wavelengths in the emission spectrum of samarium-doped high-entropy garnet aluminate and temperature to achieve fluorescence temperature sensing, also known as fluorescence intensity ratio (FIR) thermometry. More specifically, FIR here refers to... 4 G 5 / 2 → 6 H 11 / 2 The main peak of the transition launch is 568 nanometers and 4 G 5 / 2 → 6 H 7 / 2 The transition emission peak is the ratio of the fluorescence peak intensities of the two emission peaks at 617 nm.

[0038] In the above technical solution, due to Sm 3+ The coordination radius in garnet structures is relatively large, making extensive doping impossible. Furthermore, excessive doping can induce fluorescence quenching. Therefore, the value of x in the general structural formula should not be too large. Specifically, in the general structural formula of a samarium-doped high-entropy garnet aluminate ceramic material with a certain composition, 0.005 ≤ x ≤ 0.1. Figure 2 For different Sm materials 3+ The emission spectrum of this material under 405 nm violet light excitation at the desired doping concentration is typical of Sm. 3+ Linear emission, with varying emission peak intensities at different doping concentrations, is observed in this material. 3+ The luminescence intensity is highest when the doping concentration x is 0.02. Furthermore, due to Sm... 3+ This is a typical ff transition emission, and its emission peak position hardly changes due to different doped materials. This is just an example, so there is no need to elaborate on the specific composition.

[0039] Furthermore, rare earth elements include Y, Sc, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.

[0040] Re includes at least five elements from ten rare earth elements: Y, Sc, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, with a valence state of +3. The reason for selecting five elements from these ten rare earth elements in the above technical solution is structural stability. Due to the contraction of the lanthanides, the atomic radii of lanthanide elements decrease with increasing atomic number. Starting with Eu, which has a larger atomic number than Gd, the large coordination radius in the garnet structure prevents the formation of a stable garnet structure, leading to decomposition into a perovskite structure (ReAlO3), which is difficult to integrate into the garnet lattice, thus making it easier to obtain a high-entropy garnet structure. Therefore, eight rare earth elements with large atomic numbers from Gd onwards are selected, along with two other rare earth elements, Y and Sc, whose coordination radii in the garnet structure are relatively similar to the previous eight. It should be noted that different combinations of elements result in different material properties. Therefore, there is no mandatory element selection for this type of exploratory material. Thus, this invention is limited to selecting five elements from the above ten.

[0041] In the general formula, Re represents at least five elements selected from the ten rare earth elements. These selected elements serve as the high-entropy components of the high-entropy material. From the definition of high entropy, the closer the molar ratio of each component element is to the other, the better it conforms to the concept of high entropy. For example, the five-element high-entropy component might have a molar ratio of 1:1:1:1:1. However, this does not necessarily mean that this ratio is the best in terms of properties; further adjustments to the component ratios may be needed to obtain the optimal ratio. Because there are numerous different combinations of materials and components, and the applications of the prepared materials are not entirely the same, this invention does not elaborate on specific components.

[0042] Furthermore, the density of samarium-doped high-entropy garnet-structured aluminate ceramic materials is not less than 93%, their thermal conductivity at 300–1200 degrees Celsius is not higher than 4 W / m Kelvin, and their coefficient of thermal expansion is not less than 8.5 × 10⁻⁶. -6 The above data per Kelvin is due to the sintering method, which will be explained below.

[0043] Furthermore, samarium-doped high-entropy garnet-structured aluminate ceramics emit Sm+ under 405 nm ultraviolet light excitation. 3+ The characteristic linear emission spectrum of the ions has a main emission wavelength of 617 nm and a quantum efficiency of not less than 30%. By comparing the fluorescence intensity ratio of different emission peak wavelengths, it can perform temperature self-checking at high temperatures. The maximum operating temperature of its fluorescence temperature sensing is not less than 300 degrees Celsius.

[0044] Secondly, the present invention provides a method for preparing a samarium-doped high-entropy garnet-structured aluminate ceramic material, comprising:

[0045] Step S1: Weigh alumina, samarium oxide and at least five rare earth oxide powder raw materials according to the stoichiometric ratio, and add them together with a dispersant, dispersion medium and ball mill. After ball milling and drying, a fine and uniformly mixed powder raw material is obtained.

[0046] Step S2: The powder raw material is successively ground, sieved, dry pressed, debinded, and cold isostatically pressed to obtain a ceramic green body;

[0047] Step S3: The ceramic green body is subjected to high-temperature in-situ rapid reaction sintering in a vacuum Joule furnace to obtain samarium-doped high-entropy garnet structure aluminate ceramic material.

[0048] The preparation method of the present invention involves obtaining uniformly mixed and refined raw materials by ball milling, obtaining a dense raw material green body by pressurization, and then obtaining a dense samarium-doped high-entropy garnet structure aluminate ceramic material by in-situ reaction sintering using pulsed Joule heating rapid reaction sintering method. This preparation method employs pulsed Joule heating rapid reaction sintering to prepare samarium-doped high-entropy garnet-structured aluminate ceramics in situ. The preparation process is simple and easy to implement. A key characteristic of this method is the short reaction sintering time at high temperatures, which saves significant energy compared to maintaining a high temperature field for extended periods. Furthermore, the thermal barrier coating application requires only a very short thermal field maintenance time. This in-situ rapid reaction sintering method closely resembles industrial preparation conditions, resulting in thermal barrier coatings with properties more similar to those used in actual production. In addition, in-situ reaction sintering enables samarium-doped high-entropy garnet-structured aluminate ceramics to achieve high density and high quantum efficiency, with a density greater than 93%, a thermal conductivity of no more than 4 W / m Kelvin at 300–1200°C, and a coefficient of thermal expansion of no less than 8.5 × 10⁻⁶. -6 Every Kelvin.

[0049] Furthermore, polyethylene glycol is used as the dispersant to reduce the agglomeration of powder particles; alcohol or isopropanol is used as the dispersion medium to ensure good dispersion of the powder raw materials; the grinding balls are made of alumina, specifically high-density alumina grinding balls, and the mass ratio of the grinding balls is 10 mm diameter: 5 mm diameter = 1:2 to obtain a better crushing and grinding effect on rare earth oxide raw materials; the grinding speed is 200-450 rpm, and the grinding time is 5-36 hours to ensure that the raw materials are mixed evenly and the particle size distribution is concentrated, preventing the reaction from deviating from the stoichiometric ratio due to uneven mixing and thus failing to obtain a pure phase. At the same time, the raw material powder with concentrated particle size distribution can obtain a denser ceramic material. The denser the ceramic material, the smaller the standard deviation of related properties; the drying temperature is 60-120 degrees Celsius, and the drying time is 12-24 hours to completely dry the powder raw materials.

[0050] Furthermore, grinding is done manually for 10–30 minutes to loosen the raw material powder, allowing for the pressing of a denser raw material green body. Sieving involves passing the powder through 180-mesh and 300-mesh sieves sequentially to prevent large agglomerations. Dry pressing uses hard alloy tableting molds with diameters of 10 mm, 15 mm, and 18 mm, with a pressure of 10–50 kN and a holding time of 2–5 minutes. Debinding removes the dispersant polyethylene glycol at a temperature of 500–800 degrees Celsius for 3–8 hours. Cold isostatic pressing is performed in a cold isostatic press with a pressure of 180–250 MPa, held for 60–300 seconds. The purpose of cold isostatic pressing is to obtain a denser raw material green body while eliminating internal stress and uneven density distribution caused by the axial pressure of the tablet press, thereby reducing deformation and cracking during ceramic sintering.

[0051] Furthermore, the sintering temperature was set at 1500–1700 degrees Celsius, and the sintering time was 20–60 seconds, approaching the short-term temperature field maintenance conditions required for the preparation of thermal barrier coatings on turbine blades in industrial manufacturing. This resulted in a samarium-doped high-entropy garnet-structured aluminate ceramic material with a density of 93.3–96.2%, and a quantum efficiency of up to 55% under 405 nm ultraviolet light excitation. Moreover, at 1200 degrees Celsius, the thermal conductivity of the samarium-doped high-entropy garnet-structured aluminate ceramic material was 2.7–1.8 W / m Kelvin, and the coefficient of thermal expansion was 8.6–9.5 × 10⁻⁶. -6 Every Kelvin.

[0052] Furthermore, the amount of dispersant added is 2% of the total mass of alumina, samarium oxide, and at least five rare earth oxide powder raw materials; the amount of dispersion medium added is 1.5 times the total mass of alumina, samarium oxide, and at least five rare earth oxide powder raw materials; and the ball milling powder is added in a ball-to-material ratio of 1:10. In the ball-to-material ratio, the mass of the material is the total mass of alumina, samarium oxide, at least five rare earth oxide powder raw materials, dispersant, and dispersion medium.

[0053] Thirdly, this invention provides an application of samarium-doped high-entropy garnet structure aluminate ceramic materials in the field of thermal barrier coatings.

[0054] This invention has undergone numerous experiments, and some of the experimental results are presented here for reference to further describe the invention in detail. The following is a detailed description in conjunction with specific embodiments.

[0055] Example 1

[0056] A method for preparing a samarium-doped high-entropy garnet-structured aluminate ceramic material includes:

[0057] Step 1: According to (Y) 0.2 Gd 0.2 Tb0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12 Weigh out a total of 10g of powdered raw materials, namely Y2O3, Gd2O3, Tb4O7, Lu2O3, Sc2O3, Sm2O3, and Al2O3, and place them together in a 500ml ball mill jar. Then, add polyethylene glycol (2% by mass) as a dispersant and anhydrous ethanol (1.5 times by mass) as a particle dispersant. Add prepared alumina ball milling pellets at a ball-to-powder ratio of 1:10. The ball milling time is 24 hours at a speed of 300 rpm. Transfer the ball-milled raw materials to a forced-air drying oven at 80 degrees Celsius for 12–24 hours to completely dry the powdered raw materials.

[0058] Specifically, the ball milling method is planetary ball milling. Because it has more rotational dimensions, the ball milling is more thorough and uniform. The grinding jar is made of nylon or agate, and the grinding stones are high-density alumina balls. The mass ratio of the grinding stones is 10 mm diameter: 5 mm diameter = 1:2. Larger grinding stones provide greater kinetic energy during grinding, which can effectively crush and grind large and hard rare earth oxide raw materials. The final result is a raw material with a concentrated particle size distribution and uniform mixing. This prevents the reaction from deviating from the stoichiometric ratio due to incomplete mixing, thus avoiding the inability to obtain a pure phase. At the same time, the concentrated particle size distribution of the raw material powder can produce a denser ceramic material. The denser the ceramic material, the smaller the standard deviation of the relevant properties.

[0059] Step 2: Place the dried raw material into an agate mortar and grind it manually for 10-30 minutes. The purpose is to make the raw material powder looser so that a denser raw material body can be pressed out. After manual grinding, sieve the powder through a sieve. Sifting is done by passing the powder through a 180-mesh sieve and a 300-mesh sieve in turn to prevent large agglomerates in the raw material from affecting the density of the body. Then, dry press the dried powder raw material into shape. Dry pressing refers to using a hard alloy pressing mold with a diameter of 10 mm, 15 mm or 18 mm and holding it under pressure of 20 kN for 3 minutes to obtain a ceramic green body of the specified size.

[0060] Step 3: After dry pressing, the ceramic green body needs to undergo high-temperature debinding. Debinding is to remove the organic dispersant polyethylene glycol. The debinding temperature is 600 degrees Celsius, and the debinding time is 6 hours. Then, the debinded green body is subjected to cold isostatic pressing. Cold isostatic pressing is carried out in a cold isostatic press with a pressure of 200 MPa and held for 150 seconds. The purpose of cold isostatic pressing is to obtain a denser raw material green body while eliminating the internal stress and uneven density distribution caused by the axial pressure of the press, thereby reducing deformation and cracking during ceramic sintering.

[0061] Step 4: The raw material blank processed in the above steps is subjected to pulsed Joule heating rapid reaction sintering, and in-situ reaction sintering at 1650 degrees Celsius for 40 seconds to obtain (Y). 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12 A samarium-doped high-entropy garnet-structured aluminate dense ceramic material was developed, exhibiting a density of 96%, a quantum efficiency of 55% under 405 nm ultraviolet light excitation, a thermal conductivity of 1.9 W / m Kelvin at 1200°C, and a coefficient of thermal expansion of 8.8 × 10⁻⁶. –6 Each Kelvin indicates that the prepared ceramic material has good luminescent properties and thermal protection properties.

[0062] Figure 1 In this example (Y) 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12 The XRD patterns of the ceramic material after in-situ reaction sintering at 1650 degrees Celsius for 40 seconds and after holding at a high temperature of 1600 degrees Celsius for 5 hours were compared with the YAG standard card. The two characteristic peaks corresponded one-to-one, indicating that pure garnet phase was obtained by in-situ reaction sintering at 1650 degrees Celsius for 40 seconds, and the ceramic material has very good phase temperature characteristics at high temperature.

[0063] Figure 3 In this example (Y) 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12The ceramic material exhibits an emission peak under 405 nm violet light excitation, and its emission spectrum is typical of Sm... 3+ Linear emission with a main emission peak at 617 nm; after excitation, the material exhibits red-orange light emission.

[0064] Figure 4 In this example (Y) 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12 The absorption peak of the ceramic material at 617 nm indicates that the material has good absorption in the 405 nm violet and ultraviolet regions.

[0065] Figure 5 In this example (Y) 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12 Temperature-varying spectra of ceramic materials under stable excitation with 405 nm violet light from 300 to 1000 degrees Celsius. All spectra have had the influence of blackbody radiation background removed. It can be seen that the emission intensity decreases with increasing temperature, and the decrease in the 617 nm main peak is greater than that in the 569 nm peak.

[0066] Figure 6 In this example (Y) 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12 The fluorescence intensity ratio (FIR) at 569 nm and 617 nm of the ceramic material varies with temperature, and the fitted curves show that the FIR at both wavelengths has a very obvious exponential relationship with temperature. The fitted relationship is FIR = 0.474exp(-399.407 / T) + 0.125, indicating that the temperature in the range of 300-1000 degrees Celsius can be sensed by using the FIR at these two wavelengths.

[0067] Figure 7 In this example (Y) 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm0.04 Al5O 12 Surface morphology of ceramic materials after CMAS corrosion at 1350 degrees Celsius: (a) after 6 hours of corrosion; (b) after 12 hours of corrosion; (c) after 18 hours of corrosion. It can be seen that the ceramic material exhibits excellent resistance to CMAS corrosion.

[0068] Figure 8 The (Y) obtained in this example 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12 Images of ceramic materials in different sizes and specifications.

[0069] Figure 9 In this example (Y) 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12 The grain morphology of the ceramic material observed after holding at 1550 degrees Celsius for a certain period of time is as follows: (a) 0 hours; (b) 6 hours; (c) 12 hours; (d) 18 hours. The changes in the figure show that the grain growth of the ceramic material slows down with the extension of the holding time, and no obvious abnormal grain growth phenomenon is observed, indicating that the ceramic material has good anti-sintering properties.

[0070] Figure 10 For this instance (Y) 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 The average grain size of Al5O1 salt ceramic material changed at 1550 degrees Celsius for different holding times. The holding time ranged from 0 hours to 18 hours. The average grain size of the ceramic material changed from 1.1 micrometers to 2.2 micrometers. The trend in the figure shows that the grain growth rate was slower at longer holding times, which further proves that the ceramic material has good anti-sintering properties.

[0071] Example 2

[0072] The application of a samarium-doped high-entropy garnet structure aluminate ceramic material, combined with a high-temperature resistant micro-optical fiber inside the coating, allows the optical fiber to transmit excitation light while also receiving fluorescence information from the coating itself. This fluorescence information is transmitted through the optical fiber to a distant spectrometer and extracted. Subsequently, the mathematical relationship between the fluorescence signal and temperature is calculated by computer and fitted to obtain real-time temperature information, thereby realizing real-time self-detection temperature sensing of the coating.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A samarium-doped high-entropy garnet-structured aluminate ceramic material, characterized in that, The chemical structural formula is (Y 0.2 Gd 0.2 Tb 0.2 Lu 0.2 Sc 0.2 ) 2.96 Sm 0.04 Al5O 12 .

2. The samarium-doped high-entropy garnet-structured aluminate ceramic material according to claim 1, characterized in that, The density of samarium-doped high-entropy garnet-structured aluminate ceramic materials is not less than 93%, and their thermal conductivity at 300–1200 degrees Celsius is not higher than 4 W / m Kelvin, and their coefficient of thermal expansion is not less than 8.5 × 10⁻⁶. -6 Every Kelvin.

3. The samarium-doped high-entropy garnet-structured aluminate ceramic material according to claim 1, characterized in that, Samarium-doped high-entropy garnet-structured aluminate ceramics emit Sm under 405 nm ultraviolet light excitation. 3+ The characteristic linear emission spectrum of the ions has a main emission wavelength of 617 nm and a quantum efficiency of not less than 30%. By comparing the fluorescence intensity ratio of different emission peak wavelengths, it can perform temperature self-checking at high temperatures. The maximum operating temperature of its fluorescence temperature sensing is not less than 300 degrees Celsius.

4. A method for preparing samarium-doped high-entropy garnet-structured aluminate ceramic material as described in any one of claims 1-3, characterized in that, include: Weigh alumina, samarium oxide and five rare earth oxide powders according to stoichiometric ratio, and add them together with dispersant, dispersion medium and ball mill. After ball milling and drying, fine and uniformly mixed powders are obtained. The powder raw material is successively ground, sieved, dry pressed, debinded, and cold isostatic pressed to obtain a ceramic green body; High-temperature in-situ rapid reaction sintering of ceramic green bodies in a vacuum Joule furnace yields samarium-doped high-entropy garnet-structured aluminate ceramic materials.

5. The method for preparing samarium-doped high-entropy garnet-structured aluminate ceramic material according to claim 4, characterized in that, The dispersant is polyethylene glycol, the dispersion medium is alcohol or isopropanol, the ball mill is alumina, the ball milling speed is 200-450 rpm, the ball milling time is 5-36 hours, the drying temperature is 60-120 degrees Celsius, and the drying time is 12-24 hours.

6. The method for preparing samarium-doped high-entropy garnet-structured aluminate ceramic material according to claim 4, characterized in that, Grinding is done manually for 10–30 minutes; sieving is done using 180-mesh and 300-mesh sieves in sequence; dry pressing is done using carbide die molds with diameters of 10 mm, 15 mm, and 18 mm, with a pressure of 10–50 kN and a holding time of 2–5 minutes; the discharge temperature is 500–800 degrees Celsius and the discharge time is 3–8 hours; cold isostatic pressing is done in a cold isostatic press with a pressure of 180–250 MPa and a holding time of 60–300 seconds.

7. The method for preparing samarium-doped high-entropy garnet-structured aluminate ceramic material according to claim 4, characterized in that, The sintering temperature is 1500–1700 degrees Celsius, and the sintering time is 20–60 seconds.

8. The method for preparing samarium-doped high-entropy garnet-structured aluminate ceramic material according to claim 4, characterized in that, The amount of dispersant added is 2% of the total mass of alumina, samarium oxide and five rare earth oxide powder raw materials; the amount of dispersion medium added is 1.5 times the total mass of alumina, samarium oxide and five rare earth oxide powder raw materials; and the ball-to-material ratio of the added ball milling particles is 1:

10.

9. The application of a samarium-doped high-entropy garnet structure aluminate ceramic material as described in any one of claims 1-3 in the field of thermal barrier coatings.

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