A self-healing near-infrared stress-luminescent aluminum silicate-based smart material and its preparation method

Abstract

The present invention belongs to the technical field of inorganic luminescent materials. The present invention discloses a self-recovery aluminosilicate-based near-infrared stress luminescent intelligent material and a preparation method thereof. The chemical general formula of the self-recovery near-infrared stress luminescent aluminosilicate-based intelligent material of the present invention is Al2O3·xSiO2:m%Cr, where x represents the molar ratio of SiO2 to Al2O3, 0 < x < 100000; m% represents the molar percentage content of Cr relative to Al2O3·xSiO2. The self-recovery near-infrared stress luminescent aluminosilicate-based intelligent material of the present invention is inexpensive, has excellent high-temperature resistance, heat insulation and fireproof performance, the luminescence wavelength is in the range of 600 nm to 900 nm, and the main wavelength is in the near-infrared I region band. This material will directly emit light under stress without prior light irradiation. This material has high-strength elastic stress luminescence characteristics, a simple preparation process, low cost, and stable chemical properties.

Description

Technical Field

[0001] This invention relates to the field of inorganic luminescent materials technology, and in particular to a self-recovering near-infrared stress-luminescent aluminum silicate-based smart material and its preparation method. Background Technology

[0002] Currently, the commonly used technologies in the industry are as follows:

[0003] Mechanoluminescence (ML) is a phenomenon in which materials emit light when subjected to mechanical stress (such as tension, compression, bending, or friction). This phenomenon has been studied historically, particularly in mineralogy and materials science, where it has attracted widespread attention and application. Unlike traditional photoluminescence (optical excitation) and electroluminescence (electrical excitation), ML is a unique luminescence mechanism that does not require light or electricity; instead, it is triggered directly by the application of external stress. Based on the degree of stress and the material's elastic limit, ML materials can be classified as fracture-type, plastic-type, and elastic-type. Furthermore, the material's properties determine whether they can be self-healing or trap-controlled types requiring pre-excitation.

[0004] Inorganic luminescent materials have become key luminescent materials due to their structural stability and excellent performance, while stress-luminescent materials have shown great promise in numerous fields, including stress sensing, display technology, security and anti-counterfeiting, and biomedicine. For example, stress-luminescent materials can be used to develop stress sensors to monitor structural health and stress distribution; in display technology, they can achieve image display through mechanical stimulation; in security and anti-counterfeiting, these materials can be used to create anti-counterfeiting labels and security tags, using specific mechanical stimuli to verify authenticity; and in biomedicine, stress-luminescent materials can monitor changes in mechanical stress in cells and tissues. These applications fully demonstrate the broad potential and multifunctional uses of stress-luminescent materials.

[0005] Aluminum silicate is a common inorganic material, primarily composed of aluminum, silicon, and oxygen, possessing a highly stable crystal structure. This material is renowned for its excellent high-temperature resistance, chemical corrosion resistance, and good mechanical strength, and is widely used in various industries and scientific research. In the field of high-temperature materials, traditional high-temperature resistant materials such as clay bricks or alumina refractory bricks are prone to softening or melting under extreme high-temperature conditions, while aluminum silicate materials can maintain structural stability at temperatures exceeding 1700℃. In the construction and aerospace industries, aluminum silicate, due to its lightweight, high-temperature resistance, and impact resistance, is often used as a thermal insulation material, structural material, and fireproofing material.

[0006] However, high-temperature resistant and fire-retardant self-healing near-infrared stress-luminescent materials are still relatively scarce. Among the traditional near-infrared stress-luminescent materials that have been reported, the one reported by Xiamen University is SrZnSO:Nd. 3+ / Tm 3+ / Er 3+ / Yb 3+ (ML peak values: 908nm, 1094nm, 1390nm / 790nm / 1534nm / 980nm), SrZn2S2O:Yb 3+ (ML peak 980nm), SrSi2O2N2:Yb 3 + (ML peak 980nm): Nano Energy, 2020, 68:104329; South China University of Technology reported CaZnOS:Nd 3+ (ML peak 908nm, 1094nm, 1390nm): ACS applied materials&interfaces, 2018, 10(17): 14509-14516, Sr3Sn2O7:Nd 3+ (ML peak 900nm): Journal of the American Ceramic Society, 2019, 102(10): 5899-5909, LiNbO3:Nd 3+ (ML peak values ​​895nm, 928nm, 938nm): Journal of Materials Chemistry C, 2019, 7(21): 6301-6307, LiGa5O8:Pr 3+ (ML peak 861nm, 913nm): Advanced Optical Materials, 2019, 7(24): 1901107 etc. Aluminosilicate stress-luminescent materials that have been reported include NaAlSiO4:Eu, Dy: Research Journal of Engineering and Technology, 2017, 8(4): 311-314, NaAlSiO4:Eu 2+ ,Ln 3+ :Key Engineering Materials, 2016, 680: 220-223; Sr2Al2SiO7: Eu, Dy: AIP Conference Proceedings.AIP Publishing, 2019, 2104 (1); CaAl2Si2O8: Eu 2+ CaAl2Si2O8:Eu 2+ ,Dy 3+:Advanced Materials Research, 2013, 815:655-661, etc.

[0007] The difference between the near-infrared stress-luminescent material of the above invention and the material of this patent is as follows:

[0008] First, unlike other aluminosilicates with stress luminescence properties (such as CaAl2Si2O8), which emit light in the visible light band, this invention emits light in the 600nm-900nm band, with the dominant wavelength located in the near-infrared band (ML wavelength peak at 694nm). Second, compared to other materials, this invention is less expensive and commonly found in ores, giving it a significant advantage in large-scale preparation and application. Third, compared to alumina, the introduction of silicon dioxide in this invention results in better processing performance, especially in low-temperature processing and forming. The invention exhibits several advantages, such as its ability to be processed into various shapes of fire-resistant products, including blankets, sheets, pipes, and ropes, making it suitable for diverse applications. Fourth, it possesses excellent high-temperature resistance, remaining stable even under extreme conditions and resisting decomposition or chemical reactions. In contrast, traditional near-infrared stress-luminescent materials (such as CaZnOS) may experience structural degradation or performance loss at high temperatures, leading to stress-luminescence failure or reduced efficiency. Fifth, the invention combines its superior high-temperature resistance, thermal insulation properties, and stress-luminescence characteristics in thermal insulation and fireproofing applications, creating a variety of innovative solutions. For example, using this material in the thermal insulation and fireproofing layers of high-temperature industrial equipment and buildings can effectively prevent heat diffusion and fire spread, while also emitting light signals when the structure is subjected to mechanical stress or damage, providing immediate visual warnings. This dual functionality makes it particularly suitable for environments requiring high safety and real-time monitoring, such as high-temperature industrial furnaces, power plants, chemical facilities, and high-rise buildings, providing new technological means for fire prevention and structural health monitoring.

[0009] In summary, the problems with existing technologies are:

[0010] Existing technologies for stress-luminescent materials have significant limitations, particularly in combining the high-temperature resistance, heat insulation, and fireproofing properties of aluminosilicate materials with their self-recovering near-infrared stress-luminescence properties. Traditional stress-luminescent materials typically experience performance degradation or failure at high temperatures, failing to provide reliable heat insulation and fire protection. Furthermore, the luminescence efficiency and stability of these materials under mechanical stress are difficult to guarantee, limiting their application under extreme conditions. In contrast, aluminosilicate stress-luminescent materials not only possess excellent high-temperature resistance and heat insulation properties but also maintain stable luminescence characteristics under high temperatures and mechanical stress, significantly improving the reliability and safety of these materials in high-temperature industrial equipment, building fireproofing layers, and other applications requiring real-time monitoring and fireproofing. SUMMARY OF THE INVENTION

[0011] In view of the problems existing in the prior art, the present invention provides a self-recovering aluminosilicate-based near-infrared stress-emitting intelligent material and a preparation method thereof.

[0012] The present invention is a self-recovering near-infrared stress-emitting aluminosilicate-based intelligent material, which is inexpensive, has excellent high-temperature resistance, heat insulation and fireproof performance, has a luminescence wavelength in the range of 600 nm to 900 nm, and the main wavelength is located in the near-infrared I region band (NIR-I). This material will directly emit light under stress without prior light irradiation. The material has high-strength elastic stress-emitting characteristics, a simple preparation process, low cost, and stable chemical properties. It can directly respond to different forms of mechanical force signals, such as compression, tension, bending, collision, friction, torsion, etc., and the emitted light can be observed using an infrared camera.

[0013] The chemical general formula of the self-recovering near-infrared stress-emitting aluminosilicate-based intelligent material of the present invention is Al2O3·xSiO2:m%Cr, where x represents the molar ratio of SiO2 to Al2O3, 0 < x < 100000; m% represents the molar percentage content of Cr relative to Al2O3·xSiO2.

[0014] The preparation method of the self-recovering near-infrared stress-emitting aluminosilicate-based intelligent material of the present invention includes the following steps:

[0015] S1. Weigh raw materials according to the stoichiometric ratio of each element in the chemical general formula of the self-recovering near-infrared stress-emitting aluminosilicate-based intelligent material, mix the raw materials to obtain a mixed raw material, add anhydrous ethanol to the mixed raw materials, fully grind and mix evenly, and then dry in an oven to obtain a mixed powder;

[0016] S2. Place the mixed powder in S1 in an alumina crucible, calcine in a calcination furnace, and naturally cool to room temperature with the furnace;

[0017] S3. Grind the cooled powder obtained in S2 to obtain a self-recovering near-infrared stress-emitting aluminosilicate-based intelligent material.

[0018] Preferably, the raw materials used in S1 are as follows:

[0019] The raw materials corresponding to the Al element include oxides, hydroxides or carbonates of Al, and natural ores; the natural ores include at least one of feldspar, kaolinite, kyanite, and sillimanite;

[0020] The raw materials corresponding to the Si element include oxides, hydroxides or carbonates of Si;

[0021] The raw materials corresponding to the Cr element include oxides of Cr, soluble nitrates, and chlorides.

[0022] Preferably, the mixed powder is obtained by drying in S1 at 80-300°C.

[0023] Preferably, the calcination in S2 specifically involves heating to 1200–1700°C in an air or oxygen atmosphere at a heating rate of 1–100°C / min, and calcining for 3–5 hours; preferably, heating to near the melting point of silicon dioxide microcrystals.

[0024] The self-healing near-infrared stress-luminescent aluminum silicate-based smart material is ground and sieved into powder and then combined with optically transparent organic polymer elastic material PET to form a composite. This composite is then made into a sheet or coated onto the surface of the component to be tested. Under the action of mechanical external force, the stress on the composite or component can be converted into light emission, realizing a high-brightness near-infrared force-light direct energy conversion.

[0025] The self-recovering near-infrared stress-luminescent aluminum silicate-based smart material of this invention exhibits a narrow-spectrum stress emission peak located around 694 nm, with an emission wavelength in the 600 nm to 900 nm band. The material can be observed using an infrared camera under dark or natural light conditions.

[0026] The self-recovering near-infrared stress-luminescent aluminum silicate-based smart material of the present invention, within the elastic limit, has an elastic stress luminescence intensity that is proportional to the magnitude of the applied mechanical force.

[0027] The following are the beneficial effects of the present invention:

[0028] 1) The material preparation method of this invention is a traditional high-temperature solid-state method, which is simple and easy to use;

[0029] 2) The main elements required for the materials of this invention are oxygen, silicon and aluminum. These elements are the top three most abundant elements in the Earth's crust. The raw materials are easy to obtain in nature. Furthermore, this invention does not contain rare earth elements, which significantly reduces the production cost of the materials.

[0030] 3) The material of this invention has near-infrared red stress luminescence characteristics, which can be observed using an infrared camera when a certain mechanical force is applied to the material;

[0031] 4) The material of this invention can be widely used in many fields such as force sensing, bioimaging, anti-counterfeiting, and military applications. This type of material offers a potential solution to the current energy crisis and also broadens new horizons for multi-pathway energy conversion;

[0032] 5) The material of this invention has high temperature resistance and near-infrared stress luminescence properties, which can be used to develop high temperature resistant sensors in high temperature environments to realize real-time monitoring of stress changes, so as to continuously monitor and feed back data in extreme environments, which is crucial for the safe operation of energy, aviation and other fields.

[0033] 6) The material of this invention can be prepared as aluminosilicate fiber, used to produce various fireproof products, such as fireproof cloth, fireproof paper, and fire-resistant cotton. This fiber possesses excellent properties such as lightweight, heat insulation, and high-temperature resistance. In fire and high-temperature environments, it not only maintains its physical structure but also retains its near-infrared stress luminescence characteristics, thereby providing signal feedback in emergency situations and enhancing safety. Furthermore, this fiber material is suitable for manufacturing insulation layers for high-temperature equipment and pipe insulation layers, and can be used for sealing, filtering, and sound absorption in high-temperature environments, meeting the multifunctional needs of industrial applications and significantly improving equipment efficiency and safety. Attached Figure Description

[0034] Figure 1 The diagram shows the proportions of elements in the Earth's crust, which are rich in oxygen, silicon, and aluminum, elements required for the materials of this invention. Due to the abundance of these elements in nature, the materials of this invention can be readily obtained from natural resources, making them suitable for large-scale production and application.

[0035] Figure 2 This is a flowchart illustrating the preparation method of the self-recovering near-infrared stress-luminescent aluminum silicate-based smart material of the present invention.

[0036] Figure 3 The stress emission spectra of Al2O3·xSiO2:1%Cr prepared in Examples 1 to 9 of this invention are shown under a force of 30N.

[0037] Figure 4 The stress luminescence integral intensity diagrams of Al2O3·xSiO2:1%Cr prepared in Examples 1-9 of this invention under a force of 30N are shown.

[0038] Figure 5 This is a repeatable spectrum of the stress luminescence integral intensity of Al2O3·3SiO2:1%Cr prepared in Example 3 of the present invention under a force of 5N.

[0039] Figure 6 The images show the stress emission spectra of Al2O3·3SiO2:m%Cr prepared in Examples 3, 10-13 of this invention (with different Cr concentrations) under a 30N force. The inset is the corresponding integrated intensity diagram.

[0040] Figure 7 The XRD patterns are those of Al2O3·xSiO2:1%Cr prepared in Examples 1 to 9 of this invention. Detailed Implementation

[0041] The present invention will be further illustrated below with reference to specific embodiments. However, it should be understood that these embodiments are for illustrative purposes only and do not constitute a limitation on the scope of the invention.

[0042] The chemical general formula of the self - recovering near - infrared stress - luminescent aluminosilicate - based intelligent material of the present invention is Al2O3·xSiO2:m%Cr, where x represents the molar ratio of SiO2 to Al2O3, 0 < x < 100000; m% represents the molar percentage content of Cr relative to Al2O3·xSiO2; specifically, if the molar number of Al2O3 is 1, the molar number of SiO2 is x, 0 < x < 100000; m% represents the percentage of the molar number of Cr to the sum of the molar numbers of Al2O3 and SiO2.

[0043] The preparation method of the above - mentioned self - recovering near - infrared stress - luminescent aluminosilicate - based intelligent material includes the following steps:

[0044] S1. Weigh the raw materials according to the stoichiometric ratio of each element in the chemical general formula of the self - recovering near - infrared stress - luminescent aluminosilicate - based intelligent material, mix the raw materials to obtain a mixed raw material, add anhydrous ethanol to the mixed raw materials, grind and mix them evenly, and then dry them in an oven to obtain a mixed powder.

[0045] S2. Place the mixed powder in step S1 in an alumina crucible, calcine it in a calcination furnace, and naturally cool it to room temperature with the furnace.

[0046] S3. Grind the cooled powder obtained in step S2 to obtain the self - recovering near - infrared stress - luminescent aluminosilicate - based intelligent material.

[0047] In some embodiments, the raw materials used in S1 are as follows:

[0048] The raw materials corresponding to the Al element include oxides, hydroxides or carbonates of Al, and natural ores; the natural ores include at least one of feldspar, kaolinite, kyanite, and sillimanite.

[0049] The raw materials corresponding to the Si element include oxides, hydroxides or carbonates of Si.

[0050] The raw materials corresponding to the Cr element include oxides of Cr, soluble nitrates, and chlorides.

[0051] In some embodiments, the mixed powder is dried at 80 - 300 °C in S1.

[0052] In some embodiments, the calcination in S2 is specifically: heating at a heating rate of 1 - 100 °C / min to 1200 - 1700 °C in an air or oxygen atmosphere and calcining for 0.5 - 24 h; preferably, heating near the melting point of silicon oxide microcrystals.

[0053] In some embodiments, as Figure 2 shown, the preparation method of the self - recovering near - infrared stress - luminescent aluminosilicate - based intelligent material includes the following steps:

[0054] Step 1: When preparing, SiO2 and Al2O3 use their oxides, hydroxides or carbonates as raw materials, and natural ores can also be used, such as including but not limited to feldspar, kaolinite, kyanite, sillimanite, etc. Cr uses its oxide, soluble nitrate or chloride as raw material, and the addition amount is Al2O3·xSiO2: m% Cr; 0 < x < 100000; x represents the molar ratio of SiO2 to Al2O3; 0.000001 ≤ m ≤ 10.9; m% represents the molar percentage content of Cr relative to Al2O3·xSiO2. Add an appropriate amount of anhydrous ethanol or deionized water to the mixed raw materials, grind and mix evenly, and then dry to obtain the mixed powder.

[0055] Step 2: Place the milled powder in an alumina crucible or other high-temperature resistant container, and heat it to 1200 - 1700 °C in an air or oxygen atmosphere, calcine for 0.5 - 24 hours, and cool naturally with the furnace.

[0056] Step 3: Grind the obtained cooled powder to obtain the near-infrared stress luminescent material Al2O3·xSiO2: m% Cr powder. In Step 1, the mixed powder is dried at 80 - 300 °C. In Step 2, it is heated to 1200 - 1700 °C at a heating rate of 1 - 100 °C / min in an air or oxygen atmosphere, preferably near the melting point of the heat-induced silicon dioxide microcrystals.

[0057] In some embodiments, the self-recovery near-infrared stress luminescent aluminosilicate-based intelligent material is prepared by the high-temperature solid-phase method, and the preparation process includes the following steps:

[0058] S1. Raw materials: When preparing, Cr uses its oxide Cr2O3 as raw material, and the aluminosilicate matrix uses Al2O3 and SiO2 as raw materials. First, weigh the raw materials of each element according to the stoichiometric ratio, and then mix an appropriate amount of anhydrous ethanol or deionized water into the raw materials. Next, put the raw materials into an agate mortar for grinding and mixing until evenly mixed. Subsequently, place the mixed powder in an oven at 40 - 300 °C for drying to finally obtain the required stress luminescent material.

[0059] S2. Place the evenly milled powder in an alumina crucible, heat it to 1200 - 1700 °C at a heating rate of 1 - 100 °C / min in air, calcine for 0.5 - 24 hours, and finally cool naturally with the furnace.

[0060] S3. Crush and grind the cooled powder obtained in Step S2, and obtain the near-infrared stress luminescent Al2O3·xSiO2:Cr powder after passing through a 150-mesh sieve.

[0061] In some embodiments, such as Figure 1As shown, the proportion of elements in the Earth's crust is displayed, which is rich in oxygen, silicon, and aluminum, which are required for the materials of this invention. Due to the abundance of these elements in nature, the materials of this invention can be easily obtained from natural resources and are suitable for large-scale production and application.

[0062] The self-recovering near-infrared stress-luminescent aluminosilicate-based smart material of this invention has a simple structure and is easy to prepare. Alumina can be sourced from natural minerals, which are inexpensive and readily available. In thermal insulation and fireproofing applications, it combines excellent high-temperature resistance, thermal insulation and fireproofing properties with stress-luminescent characteristics, creating a variety of innovative solutions. For example, using this material in the thermal insulation and fireproofing layers of high-temperature industrial equipment and buildings can not only effectively prevent heat diffusion and fire spread, but also emit light signals when the structure is subjected to mechanical stress or damage, providing immediate visual warnings. This dual functionality makes it particularly suitable for environments requiring high safety and real-time monitoring, such as high-temperature industrial furnaces, power plants, chemical facilities, and high-rise buildings, providing new technical means for fire prevention and structural health monitoring. The material of this invention can also be used to prepare aluminosilicate fibers, a material specifically designed for high-temperature environments, possessing several excellent properties, such as low density, high heat resistance, excellent thermal stability, and low thermal conductivity. Furthermore, it exhibits excellent resistance to mechanical vibration, good elasticity, excellent sound insulation, excellent electrical insulation, and high chemical stability. In practical applications, aluminosilicate fibers are widely used in various high-temperature equipment. For example, in furnaces of the metallurgical, chemical, power, and machinery industries, it is often used as a filling material for high-temperature furnaces, an insulation layer for kilns, and an insulation project for heating network pipelines. Furthermore, this fibrous material is suitable for sealing, filtration, and noise reduction systems in high-temperature environments, and is also an ideal choice for catalyst carriers and composite material reinforcements. Alumina silicate fiber products are diverse, encompassing various forms such as sheets, blankets (felts), pipes, ropes, and bricks. These diverse product forms meet the needs of different industries and application scenarios, enabling alumina silicate fibers to play an irreplaceable role in high-temperature protection and related engineering.

[0063] The following specific embodiments further illustrate the self-healing near-infrared stress-luminescent aluminum silicate-based smart material and its preparation method of the present invention. This section further illustrates the content of the present invention in conjunction with specific embodiments, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0064] Example 1

[0065] This embodiment provides a self-healing near-infrared stress-luminescent aluminum silicate-based smart material with the general chemical formula Al2O3·SiO2:1%Cr;

[0066] Taking Al2O3·SiO2:1%Cr at 1500℃ as an example, the preparation method of the above material is illustrated below. The specific operation steps are as follows:

[0067] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and SiO2 are used as the matrix raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the raw materials are placed in an agate mortar and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until it is homogeneous to obtain a mixed powder. Subsequently, the mixed powder is dried in an oven at 80°C to finally obtain the mixed powder.

[0068] b) Place the mixed powder in an alumina crucible and heat it in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min. Then heat it from 1000°C to 1500°C at a heating rate of 5°C / min for 4 hours. Finally, allow it to cool down naturally in the furnace.

[0069] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent Al2O3·SiO2:1%Cr powder.

[0070] Example 2

[0071] This embodiment provides a self-healing near-infrared stress-luminescent aluminum silicate-based smart material with the general chemical formula Al2O3·2SiO2:1%Cr;

[0072] Taking Al2O3·2SiO2:1%Cr at 1500℃ as an example, the preparation method of the above material is illustrated below. The specific operation steps are as follows:

[0073] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and SiO2 are used as the matrix raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the raw materials are placed in an agate mortar and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until it is homogeneous to obtain a mixed powder. Subsequently, the mixed powder is dried in an oven at 80°C to finally obtain the mixed powder.

[0074] b) Place the mixed powder in an alumina crucible and heat it in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min. Then heat it from 1000°C to 1500°C at a heating rate of 5°C / min for 4 hours. Finally, allow it to cool down naturally in the furnace.

[0075] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent Al2O3·2SiO2:1%Cr powder.

[0076] Example 3

[0077] This embodiment provides a self-healing near-infrared stress-luminescent aluminum silicate-based smart material with the general chemical formula Al2O3·3SiO2:1%Cr;

[0078] The preparation method of the above material is illustrated using Al2O3·3SiO2:1%Cr at 1500℃ as an example. The specific operation steps are as follows:

[0079] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and SiO2 are used as the matrix raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the raw materials are placed in an agate mortar and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until it is homogeneous to obtain a mixed powder. Subsequently, the mixed powder is dried in an oven at 80°C to finally obtain the mixed powder.

[0080] b) Place the mixed powder in an alumina crucible and heat it in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min. Then heat it from 1000°C to 1500°C at a heating rate of 5°C / min for 4 hours. Finally, allow it to cool down naturally in the furnace.

[0081] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent Al2O3·3SiO2:1%Cr powder.

[0082] Example 4

[0083] This embodiment provides a self-healing near-infrared stress-luminescent aluminum silicate-based smart material with the general chemical formula Al2O3·4SiO2:1%Cr;

[0084] Taking Al2O3·4SiO2:1%Cr at 1500℃ as an example, the preparation method of the above material is illustrated below. The specific operation steps are as follows:

[0085] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SiO2 as raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the obtained raw materials are placed in an agate mortar, and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until homogeneous to obtain a mixed powder. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the mixed powder.

[0086] b) Place the mixed powder in an alumina crucible and heat it in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min. Then heat it from 1000°C to 1500°C at a heating rate of 5°C / min for 4 hours. Finally, allow it to cool down naturally in the furnace.

[0087] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent Al2O3·4SiO2:1%Cr powder.

[0088] Example 5

[0089] This embodiment provides a self-healing near-infrared stress-luminescent aluminum silicate-based smart material with the general chemical formula Al2O3·5SiO2:1%Cr;

[0090] The preparation method of the above material is illustrated using Al2O3·5SiO2:1%Cr at 1500℃ as an example. The specific operation steps are as follows:

[0091] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and SiO2 are used as the matrix raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the raw materials are placed in an agate mortar and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until it is homogeneous to obtain a mixed powder. Subsequently, the mixed powder is dried in an oven at 80°C to finally obtain the mixed powder.

[0092] b) Place the mixed powder in an alumina crucible and heat it in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min. Then heat it from 1000°C to 1500°C at a heating rate of 5°C / min for 4 hours. Finally, allow it to cool down naturally in the furnace.

[0093] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent Al2O3·5SiO2:1%Cr powder.

[0094] Example 6

[0095] This embodiment provides a self-healing near-infrared stress-luminescent aluminum silicate-based smart material with the general chemical formula Al2O3·6SiO2:1%Cr;

[0096] The preparation method of the above material is illustrated using Al2O3·6SiO2:1%Cr at 1500℃ as an example. The specific operation steps are as follows:

[0097] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SiO2 as raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the obtained raw materials are placed in an agate mortar, and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until homogeneous to obtain a mixed powder. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the mixed powder.

[0098] b) Place the mixed powder in an alumina crucible and heat it in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min. Then heat it from 1000°C to 1500°C at a heating rate of 5°C / min for 4 hours. Finally, allow it to cool down naturally in the furnace.

[0099] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent Al2O3·6SiO2:1%Cr powder.

[0100] Example 7

[0101] This embodiment provides a self-healing near-infrared stress-luminescent aluminum silicate-based smart material with the general chemical formula Al2O3·7SiO2:1%Cr;

[0102] Taking Al2O3·7SiO2:1%Cr at 1500℃ as an example, the preparation method of the above material is illustrated below. The specific operation steps are as follows:

[0103] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SiO2 as raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the obtained raw materials are placed in an agate mortar, and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until homogeneous to obtain a mixed powder. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the mixed powder.

[0104] b) Place the mixed powder in an alumina crucible and heat it in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min. Then heat it from 1000°C to 1500°C at a heating rate of 5°C / min for 4 hours. Finally, allow it to cool down naturally in the furnace.

[0105] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent Al2O3·7SiO2:1%Cr powder.

[0106] Example 8

[0107] This embodiment provides a self-healing near-infrared stress-luminescent aluminum silicate-based smart material with the general chemical formula Al2O3·8SiO2:1%Cr;

[0108] Taking Al2O3·8SiO2:1%Cr at 1500℃ as an example, the preparation method of the above material is illustrated below. The specific operation steps are as follows:

[0109] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SiO2 as raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the obtained raw materials are placed in an agate mortar, and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until homogeneous to obtain a mixed powder. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the mixed powder.

[0110] b) Place the mixed powder in an alumina crucible and heat it in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min. Then heat it from 1000°C to 1500°C at a heating rate of 5°C / min for 4 hours. Finally, allow it to cool down naturally in the furnace.

[0111] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent Al2O3·8SiO2:1%Cr powder.

[0112] Example 9

[0113] This embodiment provides a self-healing near-infrared stress-luminescent aluminum silicate-based smart material with the general chemical formula Al2O3·9SiO2:1%Cr;

[0114] The preparation method of the above material is illustrated using Al2O3·9SiO2:1%Cr at 1500℃ as an example. The specific operation steps are as follows:

[0115] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SiO2 as raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the obtained raw materials are placed in an agate mortar, and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until homogeneous to obtain a mixed powder. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the mixed powder.

[0116] b) Place the mixed powder in an alumina crucible and heat it in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min. Then heat it from 1000°C to 1500°C at a heating rate of 5°C / min for 4 hours. Finally, allow it to cool down naturally in the furnace.

[0117] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent Al2O3·9SiO2:1%Cr powder.

[0118] Example 10

[0119] This embodiment provides a self-healing near-infrared stress-luminescent aluminum silicate-based smart material with the general chemical formula Al2O3·3SiO2:0%Cr;

[0120] Taking Al2O3·3SiO2:0%Cr at 1500℃ as an example, the preparation method of the above material is illustrated below. The specific operation steps are as follows:

[0121] a) Raw materials: The matrix uses Al2O3 and SiO2 as raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the obtained raw materials are placed in an agate mortar, and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until it is homogeneous to obtain a mixed powder. Subsequently, the mixed powder is dried in an oven at 80°C to finally obtain the mixed powder.

[0122] b) Place the mixed powder in an alumina crucible and heat it in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min. Then heat it from 1000°C to 1500°C at a heating rate of 5°C / min for 4 hours. Finally, allow it to cool down naturally in the furnace.

[0123] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent Al2O3·3SiO2:0%Cr powder.

[0124] Example 11

[0125] This embodiment provides a self-healing near-infrared stress-luminescent aluminum silicate-based smart material with the general chemical formula Al2O3·3SiO2:0.1%Cr;

[0126] The preparation method of the above material is illustrated using Al2O3·3SiO2:0.1%Cr at 1500℃ as an example. The specific operation steps are as follows:

[0127] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SiO2 as raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the obtained raw materials are placed in an agate mortar, and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until homogeneous to obtain a mixed powder. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the mixed powder.

[0128] b) Place the mixed powder in an alumina crucible and heat it in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min. Then heat it from 1000°C to 1500°C at a heating rate of 5°C / min for 4 hours. Finally, allow it to cool down naturally in the furnace.

[0129] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent Al2O3·3SiO2:0.1%Cr powder.

[0130] Example 12

[0131] This embodiment provides a self-healing near-infrared stress-luminescent aluminum silicate-based smart material with the general chemical formula Al2O3·3SiO2:0.5%Cr;

[0132] The preparation method of the above material is illustrated using Al2O3·3SiO2:0.5%Cr at 1500℃ as an example. The specific operation steps are as follows:

[0133] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SiO2 as raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the obtained raw materials are placed in an agate mortar, and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until homogeneous to obtain a mixed powder. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the mixed powder.

[0134] b) Place the mixed powder in an alumina crucible and heat it in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min. Then heat it from 1000°C to 1500°C at a heating rate of 5°C / min for 4 hours. Finally, allow it to cool down naturally in the furnace.

[0135] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent Al2O3·3SiO2:0.5%Cr powder.

[0136] Example 13

[0137] This embodiment provides a self-healing near-infrared stress-luminescent aluminum silicate-based smart material with the general chemical formula Al2O3·3SiO2:2%Cr;

[0138] The preparation method of the above material is illustrated using Al2O3·3SiO2:2%Cr at 1500℃ as an example. The specific operation steps are as follows:

[0139] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SiO2 as raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the obtained raw materials are placed in an agate mortar, and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until homogeneous to obtain a mixed powder. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the mixed powder.

[0140] b) Place the mixed powder in an alumina crucible and heat it in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min. Then heat it from 1000°C to 1500°C at a heating rate of 5°C / min for 4 hours. Finally, allow it to cool down naturally in the furnace.

[0141] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent Al2O3·3SiO2:2%Cr powder.

[0142] Performance Characterization of Self-Recovering Near-Infrared Stress-Emitting Aluminosilicate-Based Smart Materials

[0143] Figure 3 The stress emission spectra of Al2O3·xSiO2:1%Cr prepared in Examples 1 to 9 of this invention are shown under a force of 30N. Figure 3 Al2O3·1SiO2 to Al2O3·9SiO2 correspond to the materials prepared in Examples 1 to 9, respectively.

[0144] from Figure 3 As can be seen from the above, the Al2O3·xSiO2:1%Cr of the present invention emits light in the near-infrared region of 650-850nm under a force of 30N, and the Al2O3·3SiO2:1%Cr prepared in Example 3 has the highest peak intensity.

[0145] Figure 4 The stress luminescence integral intensity diagrams of Al2O3·xSiO2:1%Cr prepared in Examples 1-9 of this invention under a force of 30N are shown. Figure 4 The horizontal axis x ranges from 1 to 9, corresponding to the materials prepared in Examples 1 to 9, respectively.

[0146] from Figure 4 As can be seen, the luminescence intensity of Al2O3·xSiO2:1%Cr of the present invention first increases and then decreases with the increase of SiO2, and the integral intensity is the highest when x=3.

[0147] Figure 5 This is a repeatable spectrum of the stress luminescence integral intensity of Al2O3·3SiO2:1%Cr prepared in Example 3 of the present invention under a force of 5N.

[0148] from Figure 5 As can be seen from the above, the Al2O3·3SiO2:1%Cr prepared in Example 3 of the present invention exhibits excellent repeatability and good self-healing properties.

[0149] Figure 6 The images show the stress emission spectra of Al2O3·3SiO2:m%Cr prepared in Examples 3, 10-13 of this invention (with different Cr concentrations) under a 30N force. The inset is the corresponding integrated intensity diagram. Figure 6 In this context, 0% mol represents the material prepared in Example 10, 0.1% mol represents the material prepared in Example 11, 0.5% mol represents the material prepared in Example 12, 1% mol represents the material prepared in Example 3, and 2% mol represents the material prepared in Example 13. Figure 6 The horizontal axis of the inset represents the molar percentage of Cr in the materials prepared in Examples 3, 10-13.

[0150] from Figure 6 As can be seen from the above, the effect of Cr on the luminescence performance of Al2O3·3SiO2:m%Cr in this invention is that the luminescence intensity first increases and then decreases with the increase of Cr, and the luminescence intensity is the highest when m=1.

[0151] Figure 7 The XRD patterns are those of Al2O3·xSiO2:1%Cr prepared in Examples 1 to 9 of this invention. Figure 7 Al2O3·SiO2 to Al2O3·9SiO2 correspond to the materials prepared in Examples 1 to 9, respectively.

[0152] from Figure 7 As can be seen from the above, the Al2O3·xSiO2:1%Cr material prepared by this invention is mainly composed of Al2O3 and SiO2 crystalline phases, indicating that the target material has been successfully prepared.

[0153] It is understood that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0154] The above are merely preferred embodiments of this application, and only specifically describe the technical principles of this application. These descriptions are only for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application, as well as other specific embodiments of this application that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of this application.

Claims

1. A self-healing near-infrared stress-luminescent aluminum silicate-based smart material, characterized in that, The self-healing near-infrared stress-luminescent aluminum silicate-based smart material has the general chemical formula Al2O3·xSiO2:m%Cr, where x represents the molar ratio of SiO2 to Al2O3, x = 3; m% represents the molar percentage content of Cr relative to Al2O3·xSiO2, m = 1; The preparation method of the self-healing near-infrared stress-luminescent aluminum silicate-based smart material includes the following steps: S1. Weigh the raw materials according to the stoichiometric ratio of each element in the chemical formula of the self-recovering near-infrared stress-luminescent aluminum silicate-based smart material, mix the raw materials to obtain a mixed raw material, add anhydrous ethanol to the mixed raw material, grind and mix thoroughly, and then dry in an oven to obtain a mixed powder. S2. Place the mixed powder from S1 into an alumina crucible and calcine it in a calcining furnace, allowing it to cool naturally to room temperature. S3. Grind the cooled powder obtained in S2 to obtain a self-healing near-infrared stress-luminescent aluminum silicate-based smart material. The raw material corresponding to Al is Al2O3; The raw material corresponding to the element Si is SiO2; The raw material corresponding to Cr is Cr2O3; The calcination process in S2 is as follows: the temperature is increased from room temperature to 1000℃ in a muffle furnace at a heating rate of 10℃ / min, and then increased from 1000℃ to 1500℃ at a heating rate of 5℃ / min for 4 hours.

2. A method for preparing a self-healing near-infrared stress-luminescent aluminum silicate-based smart material as described in claim 1, characterized in that, Includes the following steps: S1. Weigh the raw materials according to the stoichiometric ratio of each element in the chemical formula of the self-recovering near-infrared stress-luminescent aluminum silicate-based smart material, mix the raw materials to obtain a mixed raw material, add anhydrous ethanol to the mixed raw material, grind and mix thoroughly, and then dry in an oven to obtain a mixed powder. S2. Place the mixed powder from S1 into an alumina crucible and calcine it in a calcining furnace, allowing it to cool naturally to room temperature. S3. Grind the cooled powder obtained in S2 to obtain a self-healing near-infrared stress-luminescent aluminum silicate-based smart material. The raw material corresponding to Al is Al2O3; The raw material corresponding to the element Si is SiO2; The raw material corresponding to Cr is Cr2O3; The calcination process in S2 is as follows: the temperature is increased from room temperature to 1000℃ in a muffle furnace at a heating rate of 10℃ / min, and then increased from 1000℃ to 1500℃ at a heating rate of 5℃ / min for 4 hours.

3. The preparation method of the self-healing near-infrared stress-luminescent aluminum silicate-based smart material as described in claim 2, characterized in that, S1 is dried at 80-300℃ to obtain mixed powder.

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