Self-recovery near-infrared stress luminescent aluminum silicate-based intelligent material and preparation method thereof

Abstract

The invention belongs to the technical field of inorganic luminescent materials. The invention discloses a self-recovery aluminum silicate-based near-infrared stress luminescent intelligent material and a preparation method thereof. The chemical general formula of the self-recovery near-infrared stress luminescent aluminum silicate-based intelligent material is Al2O3.xSiO2: m% Cr, x represents the molar ratio of SiO2 to Al2O3, 0 lt, m represents the molar ratio of SiO2 to Al2O3, and m represents the molar ratio of SiO2 to Al2O3. Xlt; 100,000, 20,000, 20,000, 20,000; and m% represents the molar percentage content of Cr relative to Al2O3.xSiO2. The self-recovery near-infrared stress luminescent aluminum silicate-based intelligent material is low in price and excellent in high temperature resistance, heat insulation and fire resistance, the luminescent wavelength is in the wave band of 600-900 nm, the dominant wavelength is in the wave band of a near-infrared I region, and the material can directly emit light under the stress effect without pre-illumination. The material has the characteristics of high-strength elastic stress luminescence, simple preparation process, low cost and stable chemical properties.

Description

Technical Field

[0001] The invention relates to the technical field of inorganic luminescent materials, and in particular to a self-recovering near-infrared stress luminescent aluminum silicate-based intelligent material and a preparation method thereof. Background Art

[0002] At present, the commonly used existing technologies in the industry are as follows:

[0003] Mechanoluminescence (ML) is a phenomenon in which a material emits light when subjected to mechanical stress (such as stretching, compression, bending or friction). This phenomenon has been studied throughout history, especially in the fields of mineralogy and materials science, and has attracted widespread attention and application. Unlike traditional photoluminescence (light excitation) and electroluminescence (electrical excitation), mechanoluminescence is a unique luminescence mechanism that does not require light or electricity, but directly triggers the material to emit light by applying external stress. Depending on the degree of stress and the elastic limit of the material, mechanoluminescence materials can be divided into fracture type, plastic type and elastic type. In addition, the characteristics of the materials determine that they can be self-recovering or trap-controlled types that require pre-excitation.

[0004] Inorganic luminescent materials have become one of the key luminescent materials due to their structural stability and excellent performance, and stress luminescent materials have shown great application prospects in many 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, image display is achieved through mechanical stimulation; in the field of security and anti-counterfeiting, these materials can be used to make anti-counterfeiting logos and security labels, using specific mechanical stimulation to confirm authenticity; in biomedicine, stress luminescent materials can monitor mechanical stress changes 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 whose chemical composition is mainly composed of aluminum, silicon and oxygen elements, and has a highly stable crystal structure. This material is known 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 resistant materials, traditional high temperature resistant materials such as clay bricks or alumina refractory bricks are prone to soften or melt under extremely high temperature conditions, while aluminum silicate materials can maintain structural stability at temperatures as high as 1700°C. In the fields of construction and aerospace, aluminum silicate is often used as insulation material, structural material and fireproof material due to its light weight, high temperature resistance and impact resistance.

[0006] However, there is still a lack of self-recovering near-infrared stress luminescent materials that are resistant to high temperatures and fireproof. The traditional near-infrared stress luminescent materials that have been reported include SrZnSO:Nd 3+ / Tm 3+ / Er 3+ / Yb 3+ (ML peak 908nm, 1094nm, 1390nm / 790nm / 1534nm / 980nm), SrZn2S2O:Yb 3+ (ML peak 980nm), SrSi2O2N2:Yb 3 + (ML peak 980nm): Nano Energy, 2020, 68: 104329; CaZnOS:Nd reported by South China University of Technology 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 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. The reported aluminosilicate stress luminescent materials 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:

[0008] First, unlike other aluminosilicates with stress luminescence properties (such as CaAl2Si2O8, etc.) whose luminescence wavelength is in the visible light band, the luminescence wavelength of the present invention is in the 600nm-900nm band, and the main wavelength is in the near-infrared band (ML wavelength peak is 694nm); second, compared with other materials, the cost of the present invention is lower and it is commonly found in ores, which makes it have obvious advantages in large-scale preparation and application; third, compared with alumina, due to the introduction of silicon dioxide in the present invention, it has better processing performance, especially in the processing and molding process under low temperature conditions. It shows superiority, such as being able to be processed into fireproof products of various shapes, such as blankets, plates, pipes and ropes, etc., suitable for a variety of application scenarios; Fourth, the present invention has excellent high temperature resistance, can remain stable under extreme conditions, and is not easy to decompose or react chemically, while traditional near-infrared stress luminescent materials (such as CaZnOS, etc.) may undergo structural degradation or performance loss at high temperatures, resulting in failure of stress luminescence or decreased efficiency; Fifth, the present invention combines its excellent high temperature resistance, thermal insulation performance and stress luminescence characteristics in thermal insulation and fireproofing applications, creating a variety of innovative solutions. For example, the use of 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 function makes it particularly suitable for environments that require 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.

[0009] In summary, the problems existing in the prior art are:

[0010] The existing technology has obvious deficiencies in the application of stress luminescent materials, especially the inability to combine the high temperature resistance, heat insulation and fireproof properties and self-recovering near-infrared stress luminescent properties of aluminum silicate materials. Traditional stress luminescent materials usually degrade or fail in high temperature environments and cannot provide reliable heat insulation and fire protection. In addition, the luminous efficiency and stability of these materials under mechanical stress are also difficult to guarantee, which limits their application under extreme conditions. In contrast, aluminum silicate stress luminescent materials not only have excellent high temperature resistance and heat insulation properties, but also maintain stable luminescence characteristics under high temperature and mechanical stress, significantly improving the reliability and safety of materials in high-temperature industrial equipment, building fireproof layers and other applications that require real-time monitoring and fire insulation. 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 - luminescent intelligent material and a preparation method thereof.

[0012] The present invention relates to a self - recovering near - infrared stress - luminescent aluminosilicate - based intelligent material, which is inexpensive, has excellent high - temperature resistance, heat insulation and fire - proof 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 (NIR - I). This material will directly emit light under stress without prior light irradiation. It has high - strength elastic stress - luminescent 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 - 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.

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

[0015] 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 absolute 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 step 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 step S2 to obtain the self - recovering near - infrared stress - luminescent aluminosilicate - based intelligent material.

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

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

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

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

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

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

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

[0025] The self-recovering near-infrared stress luminescent aluminum silicate-based smart material of the present invention has a stress luminescent peak that is a narrow spectrum peak located near 694nm, and a luminescent wavelength in the range of 600nm to 900nm. The material can be observed using an infrared camera in the dark or under natural light conditions.

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

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

[0028] 1) The material of the present invention is prepared by a traditional high-temperature solid phase method, and the material preparation method is simple and easy to prepare;

[0029] 2) The main elements required for the material of the present invention are oxygen, silicon and aluminum, which are the top three elements in the earth's crust. The raw materials are easy to obtain in nature, and the present invention does not contain rare earth elements, thereby significantly reducing the production cost of the material;

[0030] 3) The material of the present 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 materials of the present invention can be widely used in many fields such as force sensing, bio-imaging, anti-counterfeiting, and military. Such materials provide a potential solution to the current energy crisis and also broaden new horizons for multi-path energy conversion;

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

[0033] 6) The material of the present invention can be prepared into aluminum silicate fiber, which is used to produce a variety of fireproof products, such as fireproof cloth, fireproof paper, fireproof cotton, etc. The fiber has excellent properties such as light weight, heat insulation, and high temperature resistance. It can not only maintain its physical structure in fire and high temperature environment, but also maintain its near-infrared stress luminescence characteristics, thereby providing signal feedback in emergency situations and enhancing safety. In addition, the fiber material is suitable for manufacturing the insulation layer and pipeline insulation layer of high temperature resistant equipment, and can be used for sealing, filtering, silencing, etc. in high temperature environments, meeting the multi-functional requirements in industrial applications and significantly improving the efficiency and safety of equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The content ratio of the earth's crust elements is shown, which is rich in oxygen, silicon and aluminum elements required for the material of the present invention. Due to the abundance of these elements in nature, the material of the present invention can be easily obtained from natural resources and is suitable for large-scale production and application.

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

[0036] Figure 3 This is a stress luminescence spectrum of Al2O3·xSiO2:1%Cr prepared in Examples 1 to 9 of the present invention under a force of 30N.

[0037] Figure 4 This is a stress luminescence integrated intensity diagram of Al2O3·xSiO2:1%Cr prepared in Examples 1 to 9 of the present invention under a force of 30N.

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

[0039] Figure 6 It is the stress luminescence spectrum of Al2O3·3SiO2:m%Cr (different Cr concentrations) prepared in Examples 3, 10 to 13 of the present invention under a force of 30N, and the inset is the corresponding integrated intensity diagram.

[0040] Figure 7 This is the XRD spectrum of Al2O3·xSiO2:1%Cr prepared in Examples 1 to 9 of the present invention. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with specific examples. However, it should be understood that these examples are only used to illustrate the present invention and do not constitute a limitation on the scope of the present 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 number of moles of Al2O3 is 1, the number of moles of SiO2 is x, 0 < x < 100000; m% represents the percentage of the number of moles of Cr in the sum of the number of moles 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 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 absolute ethanol to the mixed raw materials, fully grind and mix evenly, and then dry in an oven to obtain a mixed powder;

[0045] 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;

[0046] S3. Grind the cooled powder obtained in 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 to obtain the mixed powder.

[0052] In some embodiments, the calcination in S2 is specifically: heating in an air or oxygen atmosphere at a heating rate of 1 - 100 °C / min to 1200 - 1700 °C, and calcining for 0.5 - 24 h; preferably, heating to near the melting point of silica 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; 000001 ≤ m ≤ 10.9; m% represents the molar percentage content of Cr relative to Al2O3·xSiO2. Appropriate anhydrous ethanol or deionized water is added to the mixed raw materials, and after grinding and mixing evenly, it is dried to obtain mixed powder materials.

[0055] Step 2: Place the ground 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 near-infrared stress luminescent material Al2O3·xSiO2:m%Cr powder; in Step 1, the mixed powder materials are 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 heat-induced silicon oxide 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 each elemental raw material according to the stoichiometric ratio, and then mix appropriate 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 materials in an oven at 40 - 300 °C for drying to finally obtain the required stress luminescent material.

[0059] S2. Place the evenly ground 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 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 the elements in the earth's crust is shown, which is rich in oxygen, silicon and aluminum elements required for the material of the present invention. Due to the abundance of these elements in nature, the material of the present invention can be easily obtained from natural resources and is suitable for large-scale production and application.

[0062] The self-recovering near-infrared stress-luminescent aluminum silicate-based intelligent material of the present invention has a simple structure and is easy to prepare. Alumina can be a natural ore as a raw material, and the raw material cost is low and easy to obtain. In the application of thermal insulation and fire protection, it combines its excellent high temperature resistance, thermal insulation and fire protection performance and stress luminescence characteristics to create a variety of innovative solutions. For example, the use of this material in the thermal insulation and fire protection layer 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 instant visual warnings. This dual function makes it particularly suitable for environments that require 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 the present invention can also be used to prepare aluminum silicate fiber, which is a material designed for high-temperature environments and has many excellent properties, such as low bulk density, high heat resistance, excellent thermal stability and low thermal conductivity. In addition, it also exhibits excellent resistance to mechanical vibration, good elasticity, excellent sound insulation, excellent electrical insulation and high chemical stability. In practical applications, aluminum silicate fiber is widely used in various types of high-temperature equipment. For example, in furnaces in the metallurgical, chemical, electric power and mechanical industries, it is often used as a filling material for high-temperature furnaces, an insulation layer for kilns, and insulation projects for heat network pipes. In addition, this fiber material is also suitable for sealing, filtering and silencing systems in high-temperature environments, and is also an ideal choice for catalyst carriers and composite material reinforcements. Aluminum silicate fiber products are rich in variety, covering a variety of forms such as plates, blankets (felt), pipes, ropes and bricks. These diverse product forms meet the needs of different industries and application scenarios, making aluminum silicate fibers play an irreplaceable role in high-temperature protection and related projects.

[0063] The following further illustrates the self-recovering near-infrared stress luminescent aluminum silicate-based smart material and its preparation method of the present invention with specific examples. This section further illustrates the content of the present invention in conjunction with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the examples 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-recovering near-infrared stress luminescent aluminum silicate-based smart material, the general chemical formula of which is Al2O3·SiO2:1%Cr;

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

[0067] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and SiO2 are prepared using the matrix as the raw materials; firstly, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials; then, the mixture is ground and mixed until it is uniformly mixed to obtain a mixed powder; then, the mixed powder is placed in an oven at 80°C for drying to finally obtain a mixed powder;

[0068] b) placing the mixed powder in an alumina crucible, heating the mixture in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min, then heating the mixture from 1000°C to 1500°C at a heating rate of 5°C / min, calcining for 4 hours, and finally cooling the mixture naturally in the furnace;

[0069] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-recovering near-infrared stress luminescent aluminum silicate-based smart material, the general chemical formula of which is Al2O3·2SiO2:1%Cr;

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

[0073] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and SiO2 are prepared using the matrix as the raw materials; firstly, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials; then, the mixture is ground and mixed until it is uniformly mixed to obtain a mixed powder; then, the mixed powder is placed in an oven at 80°C for drying to finally obtain a mixed powder;

[0074] b) placing the mixed powder in an alumina crucible, heating the mixture in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min, then heating the mixture from 1000°C to 1500°C at a heating rate of 5°C / min, calcining for 4 hours, and finally cooling the mixture naturally in the furnace;

[0075] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-recovering near-infrared stress luminescent aluminum silicate-based smart material, the general chemical formula of which is Al2O3·3SiO2:1%Cr;

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

[0079] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and SiO2 are prepared using the matrix as the raw materials; firstly, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials; then, the mixture is ground and mixed until it is uniformly mixed to obtain a mixed powder; then, the mixed powder is placed in an oven at 80°C for drying to finally obtain a mixed powder;

[0080] b) placing the mixed powder in an alumina crucible, heating the mixture in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min, then heating the mixture from 1000°C to 1500°C at a heating rate of 5°C / min, calcining for 4 hours, and finally cooling the mixture naturally in the furnace;

[0081] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-recovering near-infrared stress luminescent aluminum silicate-based smart material, the general chemical formula of which is Al2O3·4SiO2:1%Cr;

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

[0085] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and SiO2 as the matrix; firstly, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials. Then, the mixture is ground and mixed until it is mixed evenly to obtain a mixed powder; then, the mixed powder is placed in an oven at 80°C for drying to finally obtain a mixed powder;

[0086] b) placing the mixed powder in an alumina crucible, heating the mixture in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min, then heating the mixture from 1000°C to 1500°C at a heating rate of 5°C / min, calcining for 4 hours, and finally cooling the mixture naturally in the furnace;

[0087] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-recovering near-infrared stress luminescent aluminum silicate-based smart material, the general chemical formula of which is Al2O3·5SiO2:1%Cr;

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

[0091] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and SiO2 are prepared using the matrix as the raw materials; firstly, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials; then, the mixture is ground and mixed until it is uniformly mixed to obtain a mixed powder; then, the mixed powder is placed in an oven at 80°C for drying to finally obtain a mixed powder;

[0092] b) placing the mixed powder in an alumina crucible, heating the mixture in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min, then heating the mixture from 1000°C to 1500°C at a heating rate of 5°C / min, calcining for 4 hours, and finally cooling the mixture naturally in the furnace;

[0093] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-recovering near-infrared stress luminescent aluminum silicate-based smart material, the general chemical formula of which is Al2O3·6SiO2:1%Cr;

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

[0097] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and SiO2 as the matrix; firstly, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials. Then, the mixture is ground and mixed until it is mixed evenly to obtain a mixed powder; then, the mixed powder is placed in an oven at 80°C for drying to finally obtain a mixed powder;

[0098] b) placing the mixed powder in an alumina crucible, heating the mixture in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min, then heating the mixture from 1000°C to 1500°C at a heating rate of 5°C / min, calcining for 4 hours, and finally cooling the mixture naturally in the furnace;

[0099] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-recovering near-infrared stress luminescent aluminum silicate-based smart material, the general chemical formula of which is Al2O3·7SiO2:1%Cr;

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

[0103] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and SiO2 as the matrix; firstly, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials. Then, the mixture is ground and mixed until it is mixed evenly to obtain a mixed powder; then, the mixed powder is placed in an oven at 80°C for drying to finally obtain a mixed powder;

[0104] b) placing the mixed powder in an alumina crucible, heating the mixture in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min, then heating the mixture from 1000°C to 1500°C at a heating rate of 5°C / min, calcining for 4 hours, and finally cooling the mixture naturally in the furnace;

[0105] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-recovering near-infrared stress luminescent aluminum silicate-based smart material, the general chemical formula of which is Al2O3·8SiO2:1%Cr;

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

[0109] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and SiO2 as the matrix; firstly, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials. Then, the mixture is ground and mixed until it is mixed evenly to obtain a mixed powder; then, the mixed powder is placed in an oven at 80°C for drying to finally obtain a mixed powder;

[0110] b) placing the mixed powder in an alumina crucible, heating the mixture in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min, then heating the mixture from 1000°C to 1500°C at a heating rate of 5°C / min, calcining for 4 hours, and finally cooling the mixture naturally in the furnace;

[0111] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-recovering near-infrared stress luminescent aluminum silicate-based smart material, the general chemical formula of which is Al2O3·9SiO2:1%Cr;

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

[0115] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and SiO2 as the matrix; firstly, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials. Then, the mixture is ground and mixed until it is mixed evenly to obtain a mixed powder; then, the mixed powder is placed in an oven at 80°C for drying to finally obtain a mixed powder;

[0116] b) placing the mixed powder in an alumina crucible, heating the mixture in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min, then heating the mixture from 1000°C to 1500°C at a heating rate of 5°C / min, calcining for 4 hours, and finally cooling the mixture naturally in the furnace;

[0117] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-recovering near-infrared stress luminescent aluminum silicate-based smart material, the general chemical formula of which is Al2O3·3SiO2:0%Cr;

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

[0121] a) Raw materials: The matrix uses Al2O3 and SiO2 as raw materials; firstly, weigh the raw materials of each element according to the stoichiometric ratio, then put the obtained raw materials into an agate bowl, and add sufficient anhydrous ethanol or deionized water to completely immerse the raw materials. Then grind and mix the mixture until it is evenly mixed to obtain a mixed powder; then, dry the mixed powder in an oven at 80°C to finally obtain a mixed powder;

[0122] b) placing the mixed powder in an alumina crucible, heating the mixture in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min, then heating the mixture from 1000°C to 1500°C at a heating rate of 5°C / min, calcining for 4 hours, and finally cooling the mixture naturally in the furnace;

[0123] c) crushing and grinding the cooled powder obtained in step b), and passing it through a 150-mesh sieve to obtain near-infrared stress luminescent Al2O3·3SiO2:0%Cr powder.

[0124] Embodiment 11

[0125] This embodiment provides a self-recovering near-infrared stress luminescent aluminum silicate-based smart material, the chemical formula of which is Al2O3·3SiO2:0.1%Cr;

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

[0127] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and SiO2 as the matrix; firstly, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials. Then, the mixture is ground and mixed until it is mixed evenly to obtain a mixed powder; then, the mixed powder is placed in an oven at 80°C for drying to finally obtain a mixed powder;

[0128] b) placing the mixed powder in an alumina crucible, heating the mixture in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min, then heating the mixture from 1000°C to 1500°C at a heating rate of 5°C / min, calcining for 4 hours, and finally cooling the mixture naturally in the furnace;

[0129] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-recovering near-infrared stress luminescent aluminum silicate-based smart material, the general chemical formula of which is Al2O3·3SiO2:0.5%Cr;

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

[0133] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and SiO2 as the matrix; firstly, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials. Then, the mixture is ground and mixed until it is mixed evenly to obtain a mixed powder; then, the mixed powder is placed in an oven at 80°C for drying to finally obtain a mixed powder;

[0134] b) placing the mixed powder in an alumina crucible, heating the mixture in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min, then heating the mixture from 1000°C to 1500°C at a heating rate of 5°C / min, calcining for 4 hours, and finally cooling the mixture naturally in the furnace;

[0135] c) crushing and grinding the cooled powder obtained in step b), and passing it through a 150-mesh sieve to obtain near-infrared stress luminescent Al2O3·3SiO2:0.5%Cr powder.

[0136] Embodiment 13

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

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

[0139] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and SiO2 as the matrix; firstly, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials. Then, the mixture is ground and mixed until it is mixed evenly to obtain a mixed powder; then, the mixed powder is placed in an oven at 80°C for drying to finally obtain a mixed powder;

[0140] b) placing the mixed powder in an alumina crucible, heating the mixture in a muffle furnace from room temperature (25°C) to 1000°C at a heating rate of 10°C / min, then heating the mixture from 1000°C to 1500°C at a heating rate of 5°C / min, calcining for 4 hours, and finally cooling the mixture naturally in the furnace;

[0141] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-luminescent aluminum silicate-based smart materials

[0143] Figure 3 This is a stress luminescence spectrum of Al2O3·xSiO2:1%Cr prepared in Examples 1 to 9 of the present invention under a force of 30N. Figure 3 Al2O3·1SiO2~Al2O3·9SiO2 correspond to the materials prepared in Examples 1~9 respectively.

[0144] from Figure 3 It can be seen that the luminescence band of the Al2O3·xSiO2:1%Cr of the present invention under a force of 30N is in the near-infrared region of 650 to 850nm and the peak intensity of the Al2O3·3SiO2:1%Cr prepared in Example 3 is the highest.

[0145] Figure 4 This is a stress luminescence integrated intensity diagram of Al2O3·xSiO2:1%Cr prepared in Examples 1 to 9 of the present invention under a force of 30N. Figure 4 The horizontal coordinate x is 1 to 9, corresponding to the materials prepared in Examples 1 to 9, respectively.

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

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

[0148] from Figure 5 It can be seen that the Al2O3·3SiO2:1%Cr prepared in Example 3 of the present invention has excellent repeatability and good self-recovery properties.

[0149] Figure 6 It is the stress luminescence spectrum of Al2O3·3SiO2:m%Cr (different Cr concentrations) prepared in Examples 3, 10 to 13 of the present invention under a force of 30N, and the inset is the corresponding integrated intensity diagram. Figure 6 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 abscissa in the inset represents the molar percentage of Cr in the materials prepared in Examples 3 and 10-13.

[0150] from Figure 6 It can be seen from the figure that the Cr in the Al2O3·3SiO2:m%Cr of the present invention has an effect on the luminescence performance. The luminescence intensity first increases and then decreases with the increase of Cr. When m=1, the luminescence intensity is the highest.

[0151] Figure 7 This is the XRD spectrum of Al2O3·xSiO2:1%Cr prepared in Examples 1 to 9 of the present invention. Figure 7 Al2O3·SiO2~Al2O3·9SiO2 correspond to the materials prepared in Examples 1~9 respectively.

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

[0153] It can be understood that the technical features of the above-described embodiments can be arbitrarily combined. In order to make the description concise, not all possible combinations of the technical features in the above-described 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 only preferred embodiments of the present application, and only specifically describe the technical principles of the present application. These descriptions are only for explaining the principles of the present application and cannot be interpreted as limiting the scope of protection of the present application in any way. Based on the explanation here, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application, and other specific implementation methods of the present application that can be associated with the technicians in this field without creative work, should be included in the scope of protection of the present application.

Claims

1. A self-recovering near-infrared stress-luminescent aluminum silicate-based smart material, characterized in that: The self-recovering near-infrared stress-luminescent aluminosilicate-based intelligent material has a chemical general formula of Al2O3·xSiO2:m% Cr, where x represents the molar ratio of SiO2 to Al2O3, 0 < x < 100000; and m% represents the molar percentage content of Cr relative to Al2O3·xSiO2.

2. A method for preparing the self-recovering near-infrared stress-luminescent aluminum silicate-based smart material according to claim 1, characterized in that: It includes the following steps: S1. Weigh raw materials according to the stoichiometric ratios of the elements 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 absolute ethanol to the mixed raw materials, fully grind and mix evenly, and then dry in an oven to obtain a mixed powder. S2. Place the mixed powder in S1 in an alumina crucible and calcine it in a calcination furnace, and naturally cool it to room temperature with the furnace. S3. Grind the cooled powder obtained in S2 to obtain the self-recovering near-infrared stress-luminescent aluminosilicate-based intelligent material.

3. The method for preparing the self-recovering near-infrared stress-luminescent aluminum silicate-based smart material according to claim 2, characterized in that: The raw materials used in S1 are as follows: 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. The raw materials corresponding to the Si element include oxides, hydroxides or carbonates of Si. The raw materials corresponding to the Cr element include oxides of Cr, soluble nitrates, and chlorides.

4. The method for preparing the self-recovering near-infrared stress-luminescent aluminum silicate-based smart material according to claim 2, characterized in that: In S1, the mixed powder is dried at 80 - 300 °C.

5. The method for preparing the self-recovering near-infrared stress-luminescent aluminum silicate-based smart material according to claim 2, characterized in that: The calcination in S2 is specifically: heating in an air or oxygen atmosphere at a heating rate of 1 - 100 °C / min to 1200 - 1700 °C and calcining for 0.5 - 24 h; preferably, heating to near the melting point of silicon oxide microcrystals.

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