A self-healing near-infrared stress-luminescent SrAl 12 O 19 Substrate-like smart materials and their preparation methods

Abstract

This invention belongs to the field of inorganic luminescent materials technology and discloses a self-recovering near-infrared stress-luminescent SrAl 12 O 19 Substrate-like smart materials and their preparation methods, with the general chemical formula SrAl 12 O 19 :m%Cr-n%R;0.000001≤m≤10.9,0≤n≤15;R is selected from one or more of Yb, Er, Nd, Tm, Ho, Pr, Sm, Dy or Bi, Fe, P, Ta, W, Y, La;m, n represent molar percentage content. The smart material of this invention has stable chemical properties, is easy to mass-produce, and has tunable near-infrared stress luminescence characteristics with multiple emission peaks; it can not only be used as a new type of near-infrared stress luminescence sensor, but also has wide applications in many fields such as large-area structural safety diagnosis, real-time deformation and friction stress distribution detection of highways, bridges, underground facilities, buildings and various metal and civil engineering machinery parts, stress sensors, and anti-counterfeiting.

Description

Technical Field

[0001] This invention relates to a self-healing near-infrared stress-luminescent SrAl 12 O 19 Substrate-like smart materials and their preparation methods belong to the field of inorganic luminescent materials technology. Background Technology

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

[0003] Mechanoluminescence (ML) materials are intelligent optoelectronic functional materials that emit light directly in response to mechanical forces. When various dynamic mechanical forces are applied, these materials exhibit a remarkable luminescence phenomenon. Compared to traditional electroluminescence, photoluminescence, and chemiluminescence, ML directly converts the mechanical energy applied to an object into light energy, requiring no external auxiliary energy sources such as light sources or power supplies, making it an environmentally friendly and energy-saving intelligent material. Based on the luminescence mechanism, they can be classified into elastic stress-luminescent materials, triboelectric stress-luminescent materials, and fracture stress-luminescent materials. The intensity of ML luminescence is related to the range of stress applied within the elastic deformation of the material, which gives it a wide range of applications, including intelligent anti-counterfeiting, machine tactile sensing, information processing, and stress sensing. Furthermore, they can be classified according to material properties into self-healing luminescent materials and trap-controlled luminescent materials, which determines whether the material possesses self-healing properties.

[0004] Although both photoluminescence and stress luminescence involve material luminescence, their luminescence principles, applications, and potential value differ fundamentally in many aspects:

[0005] First, photoluminescence and stress luminescence are excited by different methods. Photoluminescence is a light emission phenomenon under the excitation of a light source. Currently, commonly used photoluminescent materials include phosphors for LED lamps and long-afterglow phosphorescent materials (photo-excitation followed by light emission). Compared with photoluminescence, the uniqueness of stress luminescence lies in the fact that the light emission process does not require external light source excitation. It is a direct light emission caused by mechanical force. The excitation method of stress luminescent materials is more convenient and more convenient in practical applications.

[0006] Secondly, stress-luminescent materials have a wide range of energy sources. When subjected to mechanical forces such as compression, tension, bending, collision, friction, and torsion, changes in the internal crystal structure lead to charge redistribution, generating a built-in electric field. The luminescent centers within the crystal are excited by this internal electric field, resulting in luminescence. The mechanical energy required for stress luminescence can be either kinetic energy or environmental mechanical energy, such as wind energy, water energy, or geological kinetic energy. This physical luminescence characteristic, directly triggered by mechanical force, can be used for health monitoring of deformation, stress, or dynamic pressure in engineering structures; particularly for large structures such as buildings, airports, bridges, vehicles, aircraft, ships, various metals, plastics, and civil engineering structures, detecting cracks, defects, strain, and stress fatigue safety hazards; and for real-time non-destructive testing of underground facilities, such as stability and safety assessment of soil and rock in coal mining, tunnel excavation, and geological exploration projects. It can also be used in a range of fields, including bioimaging of artificial bones and soft tissues under stress, to detect stress distribution and strength. [Applicant Team's Previous Overview / Viewpoint Papers:] Chem Plus Chem ,2015,80(8),1209-1215; Nano Energy ,2019,55,389-400; Science Bulletin ,2020,65,1147-1149; Science Bulletin ,2021,66(3),206-209; Science Bulletin ,2023,68(6),542-545; Advanced Science ,2023,10(3),2204925; Relevant original papers by the applicant's team in the early stage: Advanced Materials ,2019,31(7),1807062; Advanced Materials ,2020,32(16),1907747; Advanced Materials ,2023,35(40),2304140; Advanced Functional Materials ,2023,33(32),2301372; Advanced Functional Materials ,2023,33(3),2209275; InfoMat ,2021,3(11),1272-1284 etc. ]

[0007] With the advancement of modern materials science and optical technology, the application scope of stress luminescence technology will be further expanded, and the demand for stress luminescence materials will also increase.

[0008] Due to their stable repeatability and excellent self-healing properties, inorganic luminescent materials possess immense development potential. As a novel type of inorganic luminescent material, the research of inorganic stress-luminescent materials is a hot research direction. They show promising application prospects in lighting technology, display technology, biomedical applications, optoelectronics, and sensors. Currently, the luminescence of known inorganic stress materials is mainly distributed in the visible light band, limiting further applications. However, near-infrared stress-luminescent materials, due to their immunity to bright environments and good bio-tissue permeability, are gradually attracting researchers' attention and becoming an important class of stress-luminescent materials. In recent years, near-infrared stress-luminescent materials have become a research hotspot. They can emit light in the near-infrared band when subjected to mechanical forces. Near-infrared stress-luminescent materials have attracted considerable attention due to their good biocompatibility and adaptability to bio-stress imaging. This novel material further broadens the application prospects in fields such as optical measurement and stress sensors. As research continues, new applications of near-infrared stress-luminescent materials are gradually being developed. They can be used to monitor the stress distribution, deformation, or damage of structures, such as in aerospace, construction engineering, and the machinery industry. Tunable multi-band emitted light can serve as a signal for detection and sensing, enabling simultaneous monitoring of multiple bands. Therefore, near-infrared stress-luminescent materials exhibit enormous potential application value and prospects in fields such as sensors and biomedicine.

[0009] However, near-infrared stress-luminescent materials that simultaneously possess tunable emission peak capabilities and multiple emission wavelengths are still relatively scarce. Currently reported near-infrared stress-luminescent materials include...

[0010] CaZnOS-Nd 3+ : Applied materials & Interfaces ,2018,10(17):14509-14516;

[0011] Sr3Sn2O7-Nd 3+ : Journal of the American Ceramic ,2019,102:5899–5909; Advanced Materials ,2020,32(25),1908083; LiNbO3-Nd 3+ : Journal of Materials Chemistry C,2019,7,6301-6307;

[0012] LiGa5O8-Pr 3+ : Advanced Optical Materials ,2019,7(24):1901107; Advanced Functional Materials ,2021,31(19),2010685;SrZn2S2O-Yb 3+ : Nano Energy ,2020,68,104329;Y3Al5O 12 -Cr 3+ : Advanced Functional Materials ,2023,33(27),2214497;ZnGa2O4-Cr 3+ : Advanced Functional Materials ,2023,33(3),2209275; Optical Materials Express ,2022,12(8),3238-3247;

[0013] LaAlO3-Cr 3+ : Advanced Powder Materials ,2024,3(2),100165;Lu3Ga 4.88 O 12 -Cr 3+ : Nano Energy ,2023,116,108811.

[0014] The difference between the near-infrared stress-luminescent material of the above invention and the material of this patent is as follows:

[0015] First, the matrix material is different; compared with other materials, SrAl 12 O 19 It has a hexagonal structure and a large c / a ratio in its unit cell. The product obtained after high-temperature solid-state firing is a plate-like structure. Compared with other materials, it does not require further processing, which is conducive to its further application in practical applications (such as coatings).

[0016] Second, SrAl 12 O 19It exhibits relatively stable physical properties (wear resistance, corrosion resistance, and high-temperature stability) and can withstand prolonged exposure to radiation, ultraviolet light, and oxygen atmospheres. It can be used under extreme conditions, has relaxed requirements for environmental conditions and excitation light sources, and has a wide range of applications, including sensors and anti-counterfeiting labels.

[0017] Third, the emission wavelength of this invention is in the 650nm-1600nm band, with the main wavelength located in the red light band (NIR-I). The stress emission wavelength peaks are 694nm and 794nm, respectively. Further doping can achieve multiple emission peaks (NIR-II) of other rare earth elements at 865nm, 902nm, 978nm, 1058nm, 1070nm, and 1524nm.

[0018] Fourth, compared with the narrow peaks of previous near-infrared stress luminescent materials, the material of this patent exhibits broad peaks, with the main peaks spanning from 650nm to 750nm and from 750nm to 900nm respectively. Further doping can achieve broad peaks for other rare earth elements in the ranges of 825nm to 890nm, 890nm to 970nm, 950nm to 1000nm, 1030nm to 1110nm, and 1485nm to 1615nm.

[0019] The strontium aluminate doped in this invention is a self-recovering near-infrared stress luminescence that can be observed directly under moderate mechanical force / pressure (~10 kPa) without the need for light source excitation and has highly repeatable luminescence (>100 times).

[0020] In summary, the problems with existing technologies are:

[0021] Many traditional materials, such as sulfide materials and doped fluorescent materials, have complex matrix structures, including lattice structure, defect types, and grain size. This complexity makes performance control and optimization extremely challenging. Furthermore, different matrix structures can lead to variations in material properties, which is detrimental to certain applications. Previous near-infrared stress-luminescent materials, such as CaZnOS, Sr3Sn2O7, LiNbO3, LiGa5O8, SrZn2S2O, and Y3Al5O3, have exhibited complex matrix structures. 12 ZnGa2O4, LaAlO3, Lu3Ga 4.88 O 12 The crystal structure is composed of multiple element ions, which is complex and often requires full rare earth doping to achieve stress luminescence. Stress luminescence originates from the ff forbidden transition of rare earth ions, resulting in low luminescence efficiency.

[0022] Compared to the aforementioned complex matrix structure, SrAl 12 O 19 The crystal structure consists of one 12-coordinated Sr2+ Cation sites and 5 different Al 3+ The matrix, composed of cation sites, provides a multi-dimensional spatial network structure, allowing for selective doping with different luminescent ions to achieve luminescence configurations of various luminescent ions and tunable wavelengths of multi-band emitted light. This enables SrAl... 12 O 19 The material exhibits strong tolerance to various rare earth ions or transition metal ions. The embodiments in this patent demonstrate the doping of transition metals into Al. 3+ Cation sites, rare earth ions doped into Sr 2+ The cation sites allow for pure transition metal doping or partial transition metal and partial rare earth doping. Compared to fully rare earth-doped luminescent materials, the near-infrared stress-emitting material of this patent can save rare earth, an important strategic resource.

[0023] Most near-infrared luminescent materials do not have a plate-like crystal structure, resulting in poor orientation of each crystal and hindering further applications. After high-temperature solid-state sintering, SrAl... 12 O 19 The crystal structure of SrAl is plate-like because the a-axis to c-axis length of the crystal is relatively large, which is conducive to the growth of a plate-like structure. Among the previous near-infrared stress-luminescent materials mentioned above, only CaZnOS can achieve a medium-thickness plate-like structure after secondary processing. However, the sulfur in CaZnOS is toxic and will pollute the environment. In contrast, SrAl 12 O 19 After firing, it forms a thin, sheet-like structure without further processing, and the material matrix contains no sulfur, making it environmentally friendly. Due to its good orientation, this sheet-like structure can be used to fabricate high-performance sensors. Furthermore, the sheet-like SrAl... 12 O 19 It adheres easily and can be widely used in coatings, enabling applications such as stability measurement of steel frame structures.

[0024] Despite SrAl 12 O 19 Photoluminescent materials have been the subject of some research and reports, but according to the survey up to this patent application, based on SrAl... 12 O 19Stress-luminescent materials have not been reported before. Photoluminescence, limited by its reliance on external light sources, restricts its practicality in some applications, particularly in environments where continuous or stable excitation is unavailable. However, stress luminescence, with its unique characteristic of not requiring external excitation, exhibits significant potential in practical applications, differing from photoluminescence, and shows broad application prospects in multiple fields. Especially in special applications requiring independent detection and autonomous assessment of structural integrity and other performance characteristics, stress luminescence offers an innovative and effective solution.

[0025] Therefore, this patent aims to further explore and utilize the near-infrared stress luminescence characteristics of strontium aluminate sheet materials with different doping concentrations and high-temperature solid-state sintering temperatures, and to develop new near-infrared stress luminescence materials and applications to meet the needs of future technological development. Summary of the Invention

[0026] To address the problems existing in the prior art, this invention provides a self-healing near-infrared stress-luminescent SrAl 12 O 19 Substrate-like smart materials and their preparation methods.

[0027] This invention is a self-healing near-infrared stress-luminescent SrAl 12 O 19 This invention relates to a substrate-like smart material, which utilizes inexpensive raw materials and emits light in the 600nm to 950nm wavelength range, with the dominant wavelength located in the near-infrared (NIR-I) band. This smart material emits light directly under mechanical force, without the need for pre-illumination. The purpose of this invention is to provide a near-infrared stress-luminescent smart material and its preparation method, thereby addressing the current shortage of such materials.

[0028] This smart material exhibits multiple emission peaks and tunable emission peaks in its elastic stress luminescence properties. It is simple to prepare, has low cost, and possesses inert chemical properties. Furthermore, this smart material can directly respond to various forms of mechanical force signals, such as compression, tension, bending, collision, friction, and torsion.

[0029] This invention relates to self-recovering near-infrared stress luminescence SrAl 12 O 19 The general chemical formula of substrate-like smart materials is SrAl. 12 O 19 m%Cr - n%R; 0.000001≤m≤10.9; 0≤n≤15; R is selected from one or more of Yb, Er, Nd, Tm, Ho, Pr, Sm, Dy or Bi, Fe, P, Ta, W, Y, La; m, n represent molar percentage content; This stress-luminescent smart material is prepared by a high-temperature solid-state method. The preparation process includes the following steps:

[0030] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and SrAl is used as the matrix. 12 O 19 The raw materials are as follows: First, weigh each element according to the stoichiometric ratio, and then mix an appropriate amount of anhydrous ethanol or deionized water into the raw materials. Next, place the raw materials in an agate mortar for grinding and mixing until they are evenly mixed. Then, place the mixed powder in an oven at 40℃~300℃ to dry, and finally obtain the desired light green stress-luminescent smart material.

[0031] b) Place the uniformly ground powder in an alumina crucible and heat it to 1300-1650°C in air at a heating rate of 1-100°C / min. Calcinate for 0.5-24 hours and then allow it to cool naturally in the furnace.

[0032] c) The cooled powder obtained in step b) is pulverized and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent SrAl. 12 O 19 Cr powder.

[0033] The self-recovering near-infrared stress-luminescent material is ground and sieved into powder, which is 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, thus realizing the direct energy conversion of near-infrared force and light.

[0034] The near-infrared stress-luminescent smart material of the present invention is characterized by a stress emission peak located around 690 nm and an emission wavelength in the 600 nm to 950 nm band. By appropriately adjusting the proportion of dopant materials, dual emission peaks at 690 nm and 790 nm can be achieved, and the intensity of the two different peaks can be adjusted.

[0035] The near-infrared stress-luminescent smart material of the present invention is characterized in that, within the elastic deformation threshold, the elastic stress luminescence intensity of the smart material is proportional to the magnitude of the applied mechanical force.

[0036] The following are the beneficial effects of this invention:

[0037] 1) The smart material prepared in this invention adopts the traditional high-temperature solid-state method, which is simple to prepare, easy to prepare in large quantities, and does not require rare earth elements.

[0038] 2) The smart material of this invention has near-infrared red stress luminescence characteristics. When a certain mechanical force is applied to the material, it can emit light in the near-infrared band.

[0039] 3) The smart materials of this invention can be widely used in many fields such as force sensing, bioimaging, anti-counterfeiting, and military applications. These smart materials offer a potential solution to the current energy crisis and also broaden new horizons for multi-pathway energy conversion. Attached Figure Description

[0040] Figure 1 This is a flowchart illustrating the preparation process of the near-infrared stress-luminescent smart material in this invention.

[0041] Figure 2 This is the product SrAl from Embodiment 1 of the present invention. 12 O 19 Stress emission spectrum of Cr (including noise).

[0042] Figure 3 This refers to SrAl products from Examples 1, 10, and 12 (different concentrations) of the present invention. 12 O 19 Normalized stress emission spectrum of Cr.

[0043] Figure 4 This is the product SrAl from Embodiment 14 of the present invention. 12 O 19 Stress emission spectrum of Cr-Yb.

[0044] Figure 5 This is the product SrAl from Embodiment 15 of the present invention. 12 O 19 Visible light stress emission spectrum of Cr-Nd.

[0045] Figure 6 This is the product SrAl from Embodiment 15 of the present invention. 12 O 19 :Infrared stress emission spectrum of Cr-Nd.

[0046] Figure 7 This is the product SrAl from Embodiment 16 of the present invention. 12 O 19 Visible light stress emission spectrum of Cr-Er.

[0047] Figure 8 This is the product SrAl from Embodiment 16 of the present invention. 12 O 19 :Infrared stress emission spectrum of Cr-Er.

[0048] Figure 9 This is the product SrAl from Embodiment 1 of the present invention. 12 O 19 Repeatability data spectrum of Cr stress luminescence intensity (including noise).

[0049] Figure 10 These are SrAl products from Examples 1-9 (at different temperatures) of the present invention. 12 O 19 Peak intensity diagram of stress luminescence of Cr.

[0050] Figure 11 This refers to SrAl products from Examples 1, 10, and 13 (different concentrations) of the present invention. 12 O 19 Peak intensity diagram of stress luminescence of Cr.

[0051] Figure 12 This refers to SrAl products from Examples 1, 10, and 13 (different concentrations) of the present invention. 12 O 19 XRD pattern of Cr.

[0052] Figure 13 This is the product SrAl from Embodiment 13 of the present invention. 12 O 19 SEM image of Cr. Detailed Implementation

[0053] 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.

[0054] like Figure 1 As shown, the preparation method of the near-infrared stress-luminescent smart material provided in Embodiment 1 of the present invention includes the following steps:

[0055] Step 1: In the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and SrCO3 and Al2O3 are used as the matrix raw materials. First, each element raw material is weighed according to the stoichiometric ratio, and then an appropriate amount of anhydrous ethanol or deionized water is mixed into the raw materials. Next, the raw materials are placed in an agate mortar for grinding and mixing until they are uniformly mixed. Subsequently, the mixed powder is dried in an oven at 80°C to finally obtain the desired green stress luminescent material precursor powder.

[0056] Step 2: Place the uniformly ground precursor powder in an alumina crucible, compact it and cover it. Heat it to 1650°C in air at a heating rate of 1-100°C / min, calcine for 4 hours, and finally let it cool naturally in the furnace.

[0057] Step 3: Crush and grind the cooled powder, then pass it through a 150-mesh sieve to obtain near-infrared stress-luminescent powder SrAl. 12 O 19 Cr 2%.

[0058]

Example 1

[0059] SrAl at 1650℃12 O 19 Taking Cr 2% as an example, the specific operating steps are as follows:

[0060] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SrCO3. First, each element raw material is weighed according to the stoichiometric ratio. Then, an appropriate amount of anhydrous ethanol or deionized water is mixed into the raw materials. Next, the raw materials are placed in an agate mortar for grinding and mixing until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material precursor powder.

[0061] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, then heat it to 1650℃ at a heating rate of 2℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0062] c) The cooled powder obtained in step b) is pulverized and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent SrAl. 12 O 19 1% Cr powder.

[0063]

Example 2

[0064] SrAl at 1600℃ 12 O 19 Taking Cr 2% as an example, the specific operating steps are as follows:

[0065] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SrCO3. First, each element raw material is weighed according to the stoichiometric ratio. Then, an appropriate amount of anhydrous ethanol or deionized water is mixed into the raw materials. Next, the raw materials are placed in an agate mortar for grinding and mixing until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material precursor powder.

[0066] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0067] c) The cooled powder obtained in step b) is pulverized and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent SrAl. 12 O 19 1% Cr powder.

[0068]

Example 3

[0069] SrAl at 1550℃ 12 O 19 Taking Cr 2% as an example, the specific operating steps are as follows:

[0070] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SrCO3. First, each element raw material is weighed according to the stoichiometric ratio. Then, an appropriate amount of anhydrous ethanol or deionized water is mixed into the raw materials. Next, the raw materials are placed in an agate mortar for grinding and mixing until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material precursor powder.

[0071] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1550℃ at a heating rate of 5℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0072] c) The cooled powder obtained in step b) is pulverized and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent SrAl. 12 O 19 1% Cr powder.

[0073]

Example 4

[0074] SrAl at 1500℃ 12 O 19 Taking Cr 2% as an example, the specific operating steps are as follows:

[0075] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SrCO3. First, each element raw material is weighed according to the stoichiometric ratio. Then, an appropriate amount of anhydrous ethanol or deionized water is mixed into the raw materials. Next, the raw materials are placed in an agate mortar for grinding and mixing until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material precursor powder.

[0076] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1500℃ at a heating rate of 5℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0077] c) The cooled powder obtained in step b) is pulverized and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent SrAl. 12 O 19 1% Cr powder.

[0078]

Example 5

[0079] SrAl at 1450℃ 12 O 19 Taking Cr 2% as an example, the specific operating steps are as follows:

[0080] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SrCO3. First, each element raw material is weighed according to the stoichiometric ratio. Then, an appropriate amount of anhydrous ethanol or deionized water is mixed into the raw materials. Next, the raw materials are placed in an agate mortar for grinding and mixing until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material precursor powder.

[0081] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1450℃ at a heating rate of 5℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0082] c) The cooled powder obtained in step b) is pulverized and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent SrAl. 12 O 19 1% Cr powder.

[0083]

Example 6

[0084] SrAl at 1400℃ 12 O 19 Taking Cr 2% as an example, the specific operating 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 SrCO3. First, each element raw material is weighed according to the stoichiometric ratio. Then, an appropriate amount of anhydrous ethanol or deionized water is mixed into the raw materials. Next, the raw materials are placed in an agate mortar for grinding and mixing until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material precursor powder.

[0086] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1400℃ at a heating rate of 5℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0087] c) The cooled powder obtained in step b) is pulverized and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent SrAl. 12 O19 1% Cr powder.

[0088]

Example 7

[0089] SrAl at 1350℃ 12 O 19 Taking Cr 2% as an example, the specific operating steps are as follows:

[0090] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SrCO3. First, each element raw material is weighed according to the stoichiometric ratio. Then, an appropriate amount of anhydrous ethanol or deionized water is mixed into the raw materials. Next, the raw materials are placed in an agate mortar for grinding and mixing until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material precursor powder.

[0091] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1350℃ at a heating rate of 5℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0092] c) The cooled powder obtained in step b) is pulverized and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent SrAl. 12 O 19 1% Cr powder.

[0093]

Example 8

[0094] SrAl at 1300℃ 12 O 19 Taking Cr 2% as an example, the specific operating steps are as follows:

[0095] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SrCO3. First, each element raw material is weighed according to the stoichiometric ratio. Then, appropriate amounts of anhydrous ethanol or deionized water are mixed into the raw materials. Next, the raw materials are placed in an agate mortar for grinding and mixing until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material precursor.

[0096] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1300℃ at a heating rate of 5℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0097] c) The cooled powder obtained in step b) is pulverized and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent SrAl.12 O 19 1% Cr powder.

[0098]

Example 9

[0099] SrAl at 1250℃ 12 O 19 Taking Cr 2% as an example, the specific operating steps are as follows:

[0100] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SrCO3. First, each element raw material is weighed according to the stoichiometric ratio. Then, appropriate amounts of anhydrous ethanol or deionized water are mixed into the raw materials. Next, the raw materials are placed in an agate mortar for grinding and mixing until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material precursor.

[0101] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1250℃ at a heating rate of 5℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0102] c) The cooled powder obtained in step b) is pulverized and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent SrAl. 12 O 19 1% Cr powder.

[0103]

Example 10

[0104] SrAl at 1650℃ 12 O 19 Taking Cr 0.1% as an example, the specific operating steps are as follows:

[0105] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SrCO3. First, each element raw material is weighed according to the stoichiometric ratio. Then, an appropriate amount of anhydrous ethanol or deionized water is mixed into the raw materials. Next, the raw materials are placed in an agate mortar for grinding and mixing until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material precursor powder.

[0106] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, then heat it to 1650℃ at a heating rate of 2℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0107] c) The cooled powder obtained in step b) is pulverized and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent SrAl. 12 O 19 1% Cr powder.

[0108]

Example 11

[0109] SrAl at 1650℃ 12 O 19 Taking Cr 0.5% as an example, the specific operating steps are as follows:

[0110] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SrCO3. First, each element raw material is weighed according to the stoichiometric ratio. Then, an appropriate amount of anhydrous ethanol or deionized water is mixed into the raw materials. Next, the raw materials are placed in an agate mortar for grinding and mixing until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material precursor powder.

[0111] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, then heat it to 1650℃ at a heating rate of 2℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0112] c) The cooled powder obtained in step b) is pulverized and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent SrAl. 12 O 19 1% Cr powder.

[0113]

Example 12

[0114] SrAl at 1650℃ 12 O 19 Taking Cr 1% as an example, the specific operating 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 SrCO3. First, each element raw material is weighed according to the stoichiometric ratio. Then, an appropriate amount of anhydrous ethanol or deionized water is mixed into the raw materials. Next, the raw materials are placed in an agate mortar for grinding and mixing until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material precursor powder.

[0116] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, then heat it to 1650℃ at a heating rate of 2℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0117] c) The cooled powder obtained in step b) is pulverized and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent SrAl. 12 O 19 1% Cr powder.

[0118]

Example 13

[0119] SrAl at 1650℃ 12 O 19 Taking Cr 4% as an example, the specific operating steps are as follows:

[0120] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and SrCO3. First, each element raw material is weighed according to the stoichiometric ratio. Then, an appropriate amount of anhydrous ethanol or deionized water is mixed into the raw materials. Next, the raw materials are placed in an agate mortar for grinding and mixing until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material precursor powder.

[0121] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, then heat it to 1650℃ at a heating rate of 2℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0122] c) The cooled powder obtained in step b) is pulverized and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent SrAl. 12 O 19 1% Cr powder.

[0123]

Example 14

[0124] SrAl at 1650℃ 12 O 19 Taking Cr 2% and Yb 1% as an example, the specific operating steps are as follows:

[0125] a) Raw materials: Cr is prepared using its oxide Cr2O3, Yb is prepared using its oxide Yb2O3, and the matrix is ​​prepared using Al2O3 and SrCO3. First, each element raw material is weighed according to its stoichiometric ratio. Then, an appropriate amount of anhydrous ethanol or deionized water is mixed into the raw materials. Next, the raw materials are placed in an agate mortar and ground and mixed until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired pink stress-luminescent material precursor powder.

[0126] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, then heat it to 1650℃ at a heating rate of 2℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0127] c) The cooled powder obtained in step b) is pulverized and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent SrAl. 12 O 19 Cr 2% - Yb 1% powder.

[0128]

Example 15

[0129] SrAl at 1650℃ 12 O 19 Taking Cr 2% and Nd 1% as an example, the specific operating steps are as follows:

[0130] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, Nd is prepared using its carbonate compound Nd2(CO3)3 as the raw material, and the matrix is ​​prepared using Al2O3 and SrCO3 as raw materials. First, each element raw material is weighed according to the stoichiometric ratio. Then, an appropriate amount of anhydrous ethanol or deionized water is mixed into the raw materials. Next, the raw materials are placed in an agate mortar for grinding and mixing until uniform. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired white stress-luminescent material precursor powder.

[0131] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, then heat it to 1650℃ at a heating rate of 2℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0132] c) The cooled powder obtained in step b) is pulverized and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent SrAl. 12 O 19 :Cr 2%-Nd 1% powder.

[0133]

Example 16

[0134] SrAl at 1650℃ 12 O 19 Taking Cr 2% - Er 1% as an example, the specific operating steps are as follows:

[0135] a) Raw materials: Cr and Er are prepared using their oxides Cr₂O₃ and Er₂O₃, respectively. The matrix is ​​composed of Al₂O₃ and SrCO₃. First, each element is weighed according to its stoichiometric ratio. Then, an appropriate amount of anhydrous ethanol or deionized water is added to the raw materials. Next, the raw materials are ground and mixed in an agate mortar until homogeneous. Subsequently, the mixed powder is dried in an oven at 80°C to obtain the desired pink stress-luminescent material precursor powder.

[0136] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, then heat it to 1650℃ at a heating rate of 2℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0137] c) The cooled powder obtained in step b) is pulverized and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent SrAl. 12 O 19 :Cr 2%-Er 1% powder.

Claims

1. A self-healing near-infrared stress-luminescent SrAl 12 O 19 Substrate-like smart materials, characterized in that, The chemical formula of the material is SrAl. 12 O 19 m%Cr-n%R, where m is 2, 0 < n ≤ 1; R is selected from Yb, Er, and Nd; m and n represent molar percentage content. The self-recovering near-infrared stress luminescence SrAl 12 O 19 The method for preparing substrate-like smart materials includes the following steps: Step 1: In the preparation, Al is prepared using its oxides, hydroxides, carbonates, corundum, or bauxite as raw materials; Sr is prepared using its oxides, carbonates, or soluble nitrates, sulfates, or chlorides as raw materials; Cr is prepared using its oxides, carbonates, or soluble nitrates, sulfates, or chlorides as raw materials; Yb, Er, and Nd are prepared using their oxides, or soluble nitrates, or chlorides as raw materials. An appropriate amount of anhydrous ethanol or deionized water is added to the mixed raw materials, and the mixture is ground and mixed evenly in an agate mortar and then dried in an oven to obtain a mixed powder. Step 2: Place the ground powder in an alumina crucible, heat it to 1200~2050℃ in an air or oxygen atmosphere, calcine for 0.5~24 hours, and then allow it to cool naturally in the furnace. Step 3: Grind the cooled powder to obtain SrAl, a near-infrared stress-luminescent smart material. 12 O 19 : m%Cr-n%R.

2. The self-healing near-infrared stress-emitting SrAl as described in claim 1 12 O 19 The method for preparing substrate-like smart materials is characterized by, Includes the following steps: Step 1: In the preparation, Al is prepared using its oxides, hydroxides, carbonates, corundum, or bauxite as raw materials; Sr is prepared using its oxides, carbonates, or soluble nitrates, sulfates, or chlorides as raw materials; Cr is prepared using its oxides, carbonates, or soluble nitrates, sulfates, or chlorides as raw materials; Yb, Er, and Nd are prepared using their oxides, or soluble nitrates, or chlorides as raw materials. An appropriate amount of anhydrous ethanol or deionized water is added to the mixed raw materials, and the mixture is ground and mixed evenly in an agate mortar and then dried in an oven to obtain a mixed powder. Step 2: Place the ground powder in an alumina crucible, heat it to 1200~2050℃ in an air or oxygen atmosphere, calcine for 0.5~24 hours, and then allow it to cool naturally in the furnace. Step 3: Grind the obtained cooled powder to obtain SrAl, a near-infrared stress-luminescent smart material. 12 O 19 : m%Cr-n%R.

3. The self-healing near-infrared stress-emitting SrAl as described in claim 2 12 O 19 The method for preparing substrate-like smart materials is characterized by: In step 1, the mixed powder is obtained by drying in an oven at 80~300℃.

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