Abnormal thermal quenching near-infrared fluorescent ceramic and its preparation method and application

Abstract

The present invention discloses an abnormal thermal quenching near-infrared fluorescent ceramic and its preparation method and application. The chemical formula of the fluorescent ceramic is: (Lu 0.34+z Y 0.66‑y‑z Sc y )3(Sc 0.85‑x Al 0.15 Cr x )2Al3O 12 , 0.0005≤ x ≤0.02, x : y =1:(5‑10), x : z =1:(10‑20). y Sc 3+ The mole percentage of dodecahedral sites occupied, x Cr ions occupy the octahedron Sc 3+ The molar percentage of the lattice site. z is the Lu in the dodecahedron 3+ The molar percentage of the metering control. The ceramic green body is formed and sintered by using the acrylamide gel injection molding method combined with high temperature solid phase reaction. The luminescent center ion in the ceramic of the present invention presents a +3 valence state under the influence of the matrix microenvironment regulator (calcium carbonate, magnesium oxide and zirconium oxide, silicon dioxide, hafnium dioxide). The excitation peak of the ceramic is between 430nm-460nm, the half-height width is between 90nm-130nm, and the half-height width is between 150nm-160nm. o The luminous intensity at 200°C is 105%-165% of the room temperature. o The luminescence intensity at 400°C is 130%-200% of that at room temperature. When excited by a 430-460 nm excitation source, the emission wavelength ranges from 650 nm to 900 nm. The ceramic preparation process is simple, and the resulting anomalous thermally quenched near-infrared fluorescent ceramic is suitable for high-power near-infrared imaging and detection.

Description

Technical Field

[0001] The present invention relates to the technical field of near-infrared luminescent ceramic materials, and in particular to an abnormal thermal quenching near-infrared fluorescent ceramic and a preparation method and application thereof. Background Art

[0002] Near-infrared (NIR) light sources, due to their excellent penetration, rapid response, bio-friendliness, compact size, high efficiency, and low cost, have attracted significant research interest in areas such as nondestructive testing, food composition analysis, night vision, and plant cultivation. The NIR spectrum, between 700 and 1000 nm, encompasses the characteristic absorption signals of CH, OH, and NH bond vibrations, making it suitable for detecting components such as sugars and proteins in food. Furthermore, NIR light can nondestructively penetrate biological tissues, offering great potential for in vivo optical imaging.

[0003] Currently, commercial near-infrared light sources include halogen lamps, near-infrared LEDs (NIR LEDs), and semiconductor lasers. However, halogen lamps are bulky, have short lifespans, and low luminous efficiency. Near-infrared LEDs and semiconductor lasers also have a narrow emission range. Compared to these traditional near-infrared light sources, PC-LEDs offer advantages such as low cost, compact structure, and high efficiency as a new generation of near-infrared light sources. The core of PC-LED devices is the phosphor conversion material, which follows mainstream technology, selecting appropriate activating ions and matrix materials, and using near-ultraviolet or blue light as the excitation source.

[0004] transition metal Cr 3+ ion is an ideal near-infrared luminescence activation ion, Cr 3+ Activated near-infrared ceramic fluorescent materials have only emerged in recent years. Cr 3+ Activating near-infrared ceramics is a hot topic and focus in the current research field. The garnet system has rich crystal field and lattice position adjustability, which can provide new possibilities for near-infrared fluorescent materials. Considering that the actual operating temperature of the device is easily exceeded 150 ℃ by high-power LED / LD excitation source, the thermal quenching behavior of luminescence is considered to be a key factor in judging the luminescence potential. Due to the instability of the material, it is easy to cause inaccurate spectrum application test. Therefore, increasing the Cr 3+ Activating the thermal stability of near-infrared garnet system ceramic luminescence has great practical significance.

[0005] Currently, the commonly used methods to improve thermal stability include: inhibiting non-radiative transitions in ceramic systems, controlling cross relaxation between the excited state of near-infrared activated ions and their ground state, controlling thermal ionization of ceramic systems, energy transfer between multiple ions, and macro-composite structure design. For example, a Chinese patent (CN 111393166 B) proposes a chemical formula (Gd z Cex Y 1-x-z )3(Sc y Al 1-y )2Al3O 12 White light LED / LD with high thermal stability ceramics, the patent makes full use of the Sc in the octahedron 3+ and Gd in a dodecahedron 3+ Forming ion pair matching effect, eliminating lattice distortion and increasing Ce 3+ Thermal stability. Chinese patent (CN116444271A) has published a chemical formula (Lu 1-x Ce x )3(Mn y Sc 1-y )2Al3O 12 However, according to the literature (J. Mater. Chem. C, 2020,8, 16427) and the literature (Ceram. Int., 2015, 41,7140–7145.), the matrix dodecahedron did not enter the high dose radius larger than Lu 3+ ionic elements, octahedral introduction exceeds 20at.%Sc 3+ After that, pure phase ceramics cannot be obtained. Therefore, this patent is a multiphase ceramic, and its thermal stability adjustment is more complicated. Chinese patent (CN 112159220 B) proposes a chemical formula (Lu y Ce z Y 1-z-y )3(Sc x Al 1-x )2Al3O 12 White light LED / LD uses high thermal stability and high quantum efficiency ceramics. This patent mainly utilizes octahedral Sc 3+ and Al 3+ The effective ionic radius formed is similar to that in the dodecahedral lattice Y 3+ He Lu 3+ The effective ion radius matching effect formed promotes the rigidity of the system structure and improves Ce 3+ Luminescence thermal stability. The literature (J Am Ceram Soc. 2020; 103: 5157-5168.) found that the composition is (Gd,Y)3(Ga,Al)5O 12 :Mn 2+ When the temperature of the ceramic increases from room temperature to 420 K, its emission intensity reaches a peak at 590 nm, which is enhanced by 33%, and then gradually decreases with further increase in temperature. 3+ 、Ga 3+ The presence of oxygen vacancies introduced will compensate for the electron detrapping of Mn at higher temperatures. 2+Energy loss caused by thermal quenching of ions.

[0006] The above-mentioned published literature mainly promotes thermal stability by changing the effective ion radius matching in ceramic or near-infrared material matrix, system structural rigidity, suppressing non-radiative transition of the system and energy transfer within the matrix. However, many literatures have confirmed that the introduction of Gd into YAG:Ce 3+ ions, although promoting Ce 3+ Ion conduction band and 5d 1 The energy separation between them suppresses thermal ionization, but the dodecahedron in the matrix produces severe distortion, which leads to the instability of the GAG ​​crystal structure. In addition, the introduction of Ga into the matrix 3+ There are also problems, Ga 3+ The raw materials of Ga are mostly oxides, which are very volatile during sintering. 3+ The introduction of will also change the position of the ceramic conduction band and affect the shallow defects of the ceramic matrix. Summary of the Invention

[0007] One of the purposes of the present invention is to provide an abnormal thermal quenching near-infrared fluorescent ceramic. o C, the luminous intensity gradually increases with the increase of temperature.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows: an abnormal thermal quenching near-infrared fluorescent ceramic, the chemical formula of which is: (Lu 0.34+z Y 0.66-y-z Sc y )3(Sc 0.85-x Al 0.15 Cr x )2Al3O 12 ,in y Sc 3+ The mole percentage of occupied dodecahedral sites, x Cr ions occupy the octahedron Sc 3+ The molar percentage of the lattice site, z is the Lu in the dodecahedron 3+ Mole percentage of metering control, 0.0005≤ x ≤0.02, x : y =1:(5-10), x : z =1:(10-20).

[0009] The second object of the present invention is to provide the above abnormal thermal quenching near-infrared fluorescent ceramic (Lu 0.34+z Y 0.66-y-z Sc y )3(Sc 0.85-x Al 0.15 Cr x)2Al3O 12 The preparation method has stable preparation technology and controllable process.

[0010] The present invention realizes abnormal thermal quenching of ceramics by actively introducing controllable defects, the types of defects are anti-site defects and oxygen vacancies. The ceramic structure is a garnet structure, the dodecahedron Lu 3+ and Sc 3+ The purpose is to increase the disorder of cations in the ceramic matrix, so that the system will produce more electron traps and increase the depth of the traps. 3+ and Sc 3+ A small part of it can be integrated into the matrix octahedral lattice to achieve the introduction and active control of antisite defects. 3+ This integration is promoted. In addition, the luminescent center ions in the ceramics are in a +3 valence state under the influence of the matrix microenvironment regulators (calcium carbonate, magnesium oxide and zirconium oxide, silicon dioxide, hafnium dioxide). Among them, calcium carbonate and magnesium oxide are called +2 valence matrix microenvironment regulators. Zirconium oxide, silicon dioxide and hafnium dioxide are called +4 valence matrix microenvironment regulators. Another function of the matrix microenvironment regulator is to control the oxygen vacancies in the ceramic matrix by changing its dosage. Under the synergistic effect of antisite defects and oxygen vacancies, when the near-infrared fluorescent ceramics are excited at room temperature, some electrons are induced to be captured and stored in the ceramic matrix trap energy level. After the temperature rises, the ceramic matrix is ​​thermally excited, and the captured electrons jump out of the trap energy level and transfer to Cr through the conduction band. 3+ The excited state energy level can achieve luminescence, provide additional excitation energy and supplement the energy loss of the system. (Lu 0.34+z Y 0.66-y-z Sc y )3(Sc 0.85-x Al 0.15 Cr x )2Al3O 12 The capture of electrons by trap energy levels in the ceramic matrix and the release of electrons from the traps reach a dynamic balance.

[0011] The present invention also provides the above (Lu 0.34+z Y 0.66-y-z Sc y )3(Sc 0.85-x Al 0.15 Cr x )2Al3O 12 The method for preparing ceramics adopts an acrylamide gel casting method combined with solid phase sintering to prepare ceramics, and specifically comprises the following steps:

[0012] (1) According to the chemical formula (Lu 0.34+z Y 0.66-y-z Sc y )3(Sc 0.85-x Al 0.15Cr x )2Al3O 12 Lutetium oxide, yttrium oxide, scandium oxide, aluminum oxide and chromium oxide with a purity of 99.5% are weighed in the stoichiometric ratio of each element as raw material powders. y Sc 3+ The mole percentage of occupied dodecahedral sites, x Cr ions occupy the octahedron Sc 3+ The molar percentage of the lattice site, z is the Lu in the dodecahedron 3+ Mole percentage of metering control, 0.0005≤ x ≤0.02, x : y =1:(5-10), x :z=1:(10-20). The raw material powder, ceramic matrix microenvironment regulator, alumina grinding balls, and alcohol are mixed in a certain proportion and ball-milled. After drying and sieving, a ceramic mixed powder is obtained. The ball milling speed is 60-110 r / min, and the ball milling time is 24 h-48 h.

[0013] (2) Gel casting slurry configuration

[0014] A premix of ammonium citrate (dispersant), tetramethylammonium hydroxide (pH adjuster), acrylamide (monomer), N,N'-methylenebisacrylamide (crosslinker), and deionized water was prepared. The ceramic mixed powder was added to the premix to prepare a gel casting slurry with a solid content of 52 vol.% to 53 vol.%. The ceramic mixed powder was added to the premix in 4-5 batches and ball milled. The slurry was then filtered and a catalyst tetramethylethylenediamine solution and an initiator ammonium persulfate solution were added in sequence. The mixture was stirred until uniformly mixed before proceeding to the next molding operation.

[0015] (3) Preparation of ceramic green body

[0016] The mixed slurry is injected into the glass mold. After the slurry is filled, the glass cover is pushed along the edge of the mold to cover it. The mold is placed in a constant temperature and humidity box with a temperature of 38-42 ° C and a humidity of 75%-80% to dry for 2-3 h / g. The green blank after drying and demoulding is placed in an alumina crucible for sintering. The slurry is sintered from room temperature to 910 o C, heating rate is 0.25-0.5℃ / min, holding temperature for 6-9h, then cooling to 200℃ at 1-2℃ / min, and then naturally cooling to room temperature to obtain ceramic green body;

[0017] (4) Ceramic sintering

[0018] The ceramic green body is sintered in a muffle furnace or a tube furnace in a nitrogen atmosphere at room temperature to 900 oThe sintering rate at C is 0.25-0.5℃ / min. o C-1450 o The sintering rate at 1450°C is 0.8-1.0°C / min. o C-1485 o The sintering rate at C is 0.25-0.5 ℃ / min, 1485 o The holding time at 1485°C is 6-10 h. o The cooling rate from 0.5°C to room temperature is 2-5°C / min. After sintering, the anomalous thermal quenching near-infrared fluorescent ceramic is obtained.

[0019] Preferably, the ceramic matrix microenvironment regulator consists of a +2-valent matrix microenvironment regulator and a +4-valent matrix microenvironment regulator, wherein the addition amount of the +2-valent matrix microenvironment regulator accounts for 5%-10% of the mass percentage of the Cr raw material chromium trioxide, preferably 5%-6%; the addition amount of the +4-valent matrix microenvironment regulator accounts for 10%-15% of the mass percentage of the Cr raw material chromium trioxide, preferably 10%-12%; the +2-valent matrix microenvironment regulator includes at least one of calcium carbonate and magnesium oxide, and the +4-valent matrix microenvironment regulator includes at least one of zirconium oxide, silicon dioxide and hafnium dioxide.

[0020] Preferably, in step (1), the mass ratio of alumina grinding balls to raw material powder is (1.2-1.3):(4-5), and the amount of alcohol used is 1.8-3.6 times the mass of the raw material powder.

[0021] Preferably, in step (1), the ball milling speed is 60-70 r / min, and the ball milling time is 24h-30h.

[0022] Preferably, in step (2), a gel casting slurry having a solid content of 52 vol.%-52.5 vol.% is prepared.

[0023] Preferably, during the ball milling in step (2), the mass ratio of the raw material powder to the grinding balls is 1:(2-3), the amount of the initiator ammonium persulfate solution used is 0.15-0.4wt.% of the ceramic mixed powder, the mass ratio of the catalyst tetramethylethylenediamine solution to acrylamide is 1:(8-12), and the stirring speed is 50 r / min-60 r / min.

[0024] Preferably, in step (2), the ceramic mixed powder is added to the premixed liquid for ball milling in 4-5 times, the amount added in the first 1-2 times is 10%-15% of the total mass of the ceramic mixed powder, and the amount added in the next 2-3 times is 25%-40% of the total mass of the ceramic mixed powder.

[0025] Preferably, when preparing the ceramic green body in step (3), the wet green body is dried in a constant temperature and humidity chamber at a temperature of 38-40°C and a humidity of 75%-76% for a standing time of 2-2.5 h / g.

[0026] Preferably, in step (4), the ceramic blank is sintered in a muffle furnace or a tube furnace in a nitrogen atmosphere at room temperature to 900 o The sintering rate at C is 0.25-0.4 ℃ / min.

[0027] Preferably, at 1460 o C-1485 o The sintering rate at C is 0.25-0.4 ℃ / min, 1485 o The holding time at C is 8-10 h.

[0028] The third object of the present invention is to provide the application of the abnormal thermal quenching near-infrared fluorescent ceramics. The abnormal thermal quenching near-infrared fluorescent ceramics provided by the present invention are pure garnet phase, Cr 3+ The crystal field strength of the ions is regulated, and the excitation peak of the ceramic is between 430 nm and 460 nm. o The luminous intensity at 200℃ is 105%-165% of the room temperature. o The luminescence intensity at room temperature was 130%-200% of that at room temperature. When the prepared near-infrared fluorescent ceramic was packaged with an excitation source (light source) with an excitation peak in the range of 430 nm-460 nm, the device exhibited an emission band of 650 nm-900 nm and a half-width (FWHM) of 90 nm-130 nm. This indicates that the anomalous thermally quenched near-infrared fluorescent ceramic provided by the present invention can be used in the field of high-power near-infrared imaging and detection.

[0029] In the present invention, the Lu 3+ and Sc 3+ The purpose is to increase the disorder of cations in the ceramic matrix, so that the system will produce more electron traps and increase the depth of the traps. The defects here are mainly anti-site defects. 3+ and Sc 3+ A small part of it can be integrated into the matrix octahedral lattice. 3+ This integration is promoted. At the same time, calcium carbonate, magnesium oxide and zirconium oxide, silicon dioxide, and hafnium dioxide are ceramic matrix microenvironment regulators. The introduction of +2-valent and +4-valent matrix microenvironment regulators can generate oxygen vacancy defects in ceramics on the basis of system charge stability. By controlling the amount of the above raw materials, the number and depth of antisite defects and oxygen vacancies in the ceramics can be synergistically controlled. After the temperature rises, the ceramic matrix is ​​thermally excited, and the trapped electrons jump out of the trap energy level and transfer to the Cr through the conduction band. 3+The excited state energy level can realize luminescence, provide additional excitation energy and supplement the energy loss of the system, thus realizing the anomalous thermal quenching characteristics of near-infrared fluorescent ceramics.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The present invention accurately controls Lu 3+ and Sc 3+ The molar mass of Y to replace the dodecahedron in the matrix 3+ ions, and control the Sc in the octahedron 3+ The molar mass of the cations in the ceramic matrix is ​​increased, and controllable electron trap antisite defects are actively introduced under the premise of stable existence of the garnet phase.

[0032] (2) The near-infrared fluorescent ceramic provided by the present invention effectively solves the problems of the half-width at half maximum of the emission spectrum and the narrow emission band, and realizes broadband emission.

[0033] (3) The near-infrared fluorescent ceramic provided by the present invention effectively solves the problem of low quantum efficiency. The internal quantum efficiency of the ceramic is between 70-85.

[0034] (4) The present invention provides near-infrared fluorescent ceramics with abnormal thermal quenching characteristics by synergistically controlling the number and depth of antisite defects and oxygen vacancies in the ceramics. o The luminous intensity at 200℃ is 105%-165% of the room temperature. o The luminous intensity at 400 °C is 130%-200% of that at room temperature.

[0035] (5) The ceramic matrix microenvironment regulator promotes the complete conversion of the valence state of Cr in the ceramic to +3, ensures the stability of the +3 valence state of Cr ions in the ceramic, and controls the oxygen vacancies in the ceramic.

[0036] (6) The near-infrared fluorescent ceramic provided by the present invention can be used in the field of high-power near-infrared imaging and detection after being packaged with a blue light LED / LD excitation source. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The figures are actual pictures of the near-infrared ceramics prepared in Examples 1-3 and Comparative Examples 1-2 of the present invention;

[0038] Figure 2 The emission spectra of the near-infrared ceramics prepared in Examples 1-3 of the present invention are shown;

[0039] Figure 3 XRD patterns of the near-infrared ceramics prepared in Examples 1-3 and Comparative Examples 1-2 of the present invention;

[0040] Figure 4The near-infrared ceramic temperature-varying spectra obtained in Examples 1-3 and Comparative Examples 1-2 of the present invention are shown;

[0041] Figure 5 These are SEM images of the near-infrared ceramics prepared in Examples 1-3 of the present invention.

[0042] Figure 6 Reflection spectra of the near-infrared ceramics prepared in Examples 1 to 3 of the present invention and Counterexample 1.

[0043] Figure 7 The electroluminescence spectra of the near-infrared ceramics prepared in Examples 1-3 of the present invention are shown. DETAILED DESCRIPTION

[0044] The present invention will be further described in detail below with reference to the accompanying drawings and specific examples. It should be understood that the following examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention, and that those skilled in the art may make non-essential improvements and adjustments based on the contents of the above invention.

[0045] The raw material powders used in the following examples and comparative examples were all commercially available products with a purity greater than 99.5%. The particle sizes of lutetium oxide, yttrium oxide, scandium oxide, aluminum oxide, and chromium oxide ranged from 100 nm to 20 μm, while the matrix microenvironment modifiers calcium carbonate, magnesium oxide, zirconium oxide, silicon dioxide, and hafnium dioxide ranged from 1 nm to 10 nm.

[0046] Example 1: (Lu 0.345 Y 0.6525 Sc 0.0025 )3(Sc 0.8495 Al 0.15 Cr 0.0005 )2Al3O 12 Preparation of Abnormal Thermal Quenching Near-Infrared Fluorescent Ceramics

[0047] (1) Set the target product (Lu 0.345 Y 0.6525 Sc 0.0025 )3(Sc 0.8495 Al 0.15 Cr 0.0005 )2Al3O 12Lutetium oxide, yttrium oxide, scandium oxide, aluminum oxide, and chromium trioxide were weighed as raw material powders according to the stoichiometric ratios of the elements in the above chemical formula. The raw material powders, ceramic matrix microenvironment modifiers, aluminum oxide grinding balls, and alcohol were mixed in a specific proportion and ball-milled at a speed of 60 r / min for 24 hours. The mixed ceramic powder was dried and sieved to obtain the final product. The divalent matrix microenvironment modifiers (calcium carbonate and magnesium oxide) were added in an amount of 5wt% of the mass of the chromium trioxide, and the tetravalent matrix microenvironment modifiers (zirconia, silicon dioxide, and hafnium dioxide) were added in an amount of 10wt% of the mass of the chromium trioxide. The mass ratio of aluminum oxide grinding balls to raw material powders was 1.2:4, and the amount of alcohol was 1.8 times the mass of the raw material powders.

[0048] (2) The dispersant ammonium citrate, the pH regulator tetramethylammonium hydroxide, the monomer acrylamide, the crosslinking agent, and deionized water are mixed to prepare a premix; wherein the amount of ammonium citrate is 0.1 wt% of the total mass of the ceramic mixed powder, the amount of tetramethylammonium hydroxide is 0.5 wt% of the total mass of the ceramic mixed powder, the amount of acrylamide is 1 wt% of the total mass of the ceramic mixed powder, and the mass ratio of N,N'-methylenebisacrylamide to acrylamide is 1:5; the ceramic mixed powder is added to the premix in 4 times and ball milled to prepare a gel casting slurry with a solid content of 52 vol.%. The amount of the first and second additions is 10% and 10% of the total mass of the ceramic mixed powder, respectively, and the amount of the last two additions is 40% and 40% of the mass of the ceramic mixed powder, respectively; the mass ratio of the ceramic mixed powder to the grinding ball is 1:2. The slurry is then filtered out, and the catalyst tetramethylethylenediamine solution and the initiator ammonium persulfate solution are added in sequence, and the amount of the initiator is 0.15 wt.% of the ceramic mixed powder. The mass ratio of the catalyst to acrylamide is 1:8; after stirring and mixing evenly at a stirring speed of 50 r / min, the next molding operation can be carried out.

[0049] (3) Pour the slurry mixed evenly in step (2) into a glass mold. After the slurry is filled, push the glass cover plate along the edge of the mold to cover it. Place it in a constant temperature and humidity box at a temperature of 38°C and a humidity of 75% to dry for 2 h / g. After drying, place the demoulded blank in an alumina crucible for sintering. The sintering system is: sintering from room temperature to 910 o C, the heating rate is 0.25 ℃ / min. o C, keep it warm for 6 h, then cool it to 200 C at a rate of 1 C / min, and then cool it naturally to room temperature to obtain a ceramic green body.

[0050] (4) The ceramic blank is sintered in a muffle furnace or a tube furnace in a nitrogen atmosphere at room temperature to 900 o The sintering rate at C is 0.25℃ / min, 900o C-1450 o The sintering rate at 1450°C was 0.8°C / min. o C-1485 o The sintering rate at 1485°C was 0.25°C / min. o C for 6 hours, then 1485 o The temperature was cooled to room temperature at a rate of 2°C / min. After sintering, the anomalous thermal quenching near-infrared fluorescent ceramic was obtained.

[0051] (5) The ceramic obtained in step (4) is mechanically thinned to a thickness of 1.0 mm to obtain a fluorescent ceramic for high-power near-infrared imaging and detection. See the actual picture for details. Figure 1 (Ceramic of Example 1) is a light green anomalous thermally quenched near-infrared fluorescent ceramic.

[0052] The valence state of the luminescent center ion in the near-infrared fluorescent ceramic prepared in this embodiment is +3. The ceramic has a garnet phase structure (see attached Figure 3 ), the excitation peak of the ceramic is 430nm, the half-height width is 90nm, and at 150 o The luminous intensity at 200°C is 165% of the room temperature. o The luminescence intensity at 400°C is 200% of that at room temperature. When excited by an excitation source with a wavelength of 430 nm, the emission band is between 650 nm and 900 nm.

[0053] Example 2: (Lu 0.74 Y 0.06 Sc 0.2 )3(Sc 0.83 Al 0.15 Cr 0.02 )2Al3O 12 Preparation of Abnormal Thermal Quenching Near-Infrared Fluorescent Ceramics

[0054] (1) Set the target product (Lu 0.74 Y 0.06 Sc 0.2 )3(Sc 0.83 Al 0.15 Cr 0.02 )2Al3O 12Lutetium oxide, yttrium oxide, scandium oxide, aluminum oxide, and chromium oxide were weighed as raw material powders according to the stoichiometric ratios of the elements in the above chemical formula. The raw material powders, ceramic matrix microenvironment modifiers, aluminum oxide grinding balls, and alcohol were mixed in a specific proportion and ball-milled at a speed of 110 r / min for 48 h. The mixed powder was dried and sieved to obtain the final product. The +2-valent matrix microenvironment modifiers (calcium carbonate and magnesium oxide) were added in an amount of 10 wt% of the mass of chromium oxide. The +4-valent matrix microenvironment modifiers (zirconia, silicon dioxide, and hafnium dioxide) were added in an amount of 15 wt% of the mass of chromium oxide. The mass ratio of aluminum oxide grinding balls to raw material powders was 1.3:5, and the amount of alcohol was 3.6 times the mass of the powder.

[0055] (2) Dispersant ammonium citrate, pH regulator tetramethylammonium hydroxide, monomer acrylamide, crosslinking agent, and deionized water were mixed to prepare a premix; wherein the amount of ammonium citrate was 0.2 wt% of the total mass of the ceramic mixed powder, the amount of tetramethylammonium hydroxide was 0.8 wt% of the total mass of the ceramic mixed powder, the amount of acrylamide was 1.5 wt% of the total mass of the ceramic mixed powder, and the mass ratio of N,N'-methylenebisacrylamide to acrylamide was 1:8; the ceramic mixed powder was added to the premix in 5 batches and ball milled to prepare a gel casting slurry with a solid content of 53 vol.%. The amount added in the first and second batches was 10% and 15% of the total mass of the ceramic mixed powder, respectively, and the amount added in the last three batches was 25%, 25%, and 25% of the total mass of the ceramic mixed powder, respectively; the mass ratio of raw material powder to grinding balls was 1:3. The slurry is then filtered and a solution of tetramethylethylenediamine catalyst and an initiator, ammonium persulfate, are added sequentially. The initiator is used at a concentration of 0.4 wt.% of the ceramic powder mixture. The mass ratio of catalyst to acrylamide is 1:12. Stirring at 60 rpm until uniformly mixed, the next step, molding, is then performed.

[0056] (3) Pour the mixed slurry into the glass mold. After the slurry is filled, push the glass cover along the edge of the mold to cover it. Place it in a constant temperature and humidity box at 42 °C and 80% for 3 h / g to dry. After drying, place the demoulded green blank in an alumina crucible for sintering. The sintering schedule is: sintering from room temperature to 910 o C, heating rate is 0.5℃ / min. o C, keep warm for 9 hours, then cool to 200°C at a rate of 2°C / min, and then cool naturally to room temperature to obtain a ceramic green body.

[0057] (4) The ceramic blank is sintered in a muffle furnace or a tube furnace in a nitrogen atmosphere at room temperature to 900 o The sintering rate at C is 0.5℃ / min.o C-1450 o The sintering rate at 1450°C was 1.0°C / min. o C-1485 o The sintering rate at 1485 C was 0.5 ° C / min. o C for 6 hours. Then 1485 o The temperature was cooled to room temperature at a rate of 5 °C / min. The sintered ceramics were anomalous thermal quenching near-infrared fluorescent ceramics.

[0058] (5) The ceramic obtained in step (4) is mechanically thinned to a thickness of 1.0 mm to obtain a fluorescent ceramic for high-power near-infrared imaging and detection. See the actual picture for details. Figure 1 (Ceramic of Example 2) is a light green anomalous thermally quenched near-infrared fluorescent ceramic.

[0059] The valence state of the luminescent center ion in the prepared near-infrared fluorescent ceramic is +3. The ceramic has a garnet phase structure (see Appendix Figure 3 ), the excitation peak of the ceramic is 460nm, the half-height width is 130nm, and at 150 o The luminous intensity at 200°C is 105% of the room temperature. o The luminescence intensity at 400°C is 130% of that at room temperature. When excited by an excitation source with a wavelength of 460 nm, the emission band is between 650 nm and 900 nm.

[0060] Example 3: (Lu 0.49 Y 0.43 Sc 0.08 )3(Sc 0.84 Al 0.15 Cr 0.01 )2Al3O 12 Preparation of Abnormal Thermal Quenching Near-Infrared Fluorescent Ceramics

[0061] (1) Set the target product (Lu 0.49 Y 0.43 Sc 0.08 )3(Sc 0.84 Al 0.15 Cr 0.01 )2Al3O 12Lutetium oxide, yttrium oxide, scandium oxide, aluminum oxide, and chromium oxide were weighed as raw material powders according to the stoichiometric ratios of the elements in the above chemical formula. The raw material powders, ceramic matrix microenvironment modifiers, alumina grinding balls, and alcohol were mixed in a specific proportion and ball-milled at a speed of 80 r / min for 30 h. The mixed powder was dried and sieved to obtain the final product. The amount of the divalent matrix microenvironment modifiers (calcium carbonate and magnesium oxide) added was 8 wt% of the mass of the chromium oxide. The amount of the tetravalent matrix microenvironment modifiers (zirconia, silicon dioxide, and hafnium dioxide) added was 12 wt% of the mass of the chromium oxide. The mass ratio of alumina grinding balls to raw material powders was 1.25:4.5, and the amount of alcohol used was 2.4 times the mass of the powder.

[0062] (2) Dispersant ammonium citrate, pH regulator tetramethylammonium hydroxide, monomer acrylamide, crosslinking agent, and deionized water were mixed to prepare a premix; wherein the amount of ammonium citrate was 0.15 wt% of the total mass of the ceramic mixed powder, the amount of tetramethylammonium hydroxide was 0.6 wt% of the total mass of the ceramic mixed powder, the amount of acrylamide was 1.2 wt% of the total mass of the ceramic mixed powder, and the mass ratio of N,N'-methylenebisacrylamide to acrylamide was 1:7; the ceramic mixed powder was added to the premix in 4 batches and ball milled to prepare a gel casting slurry with a solid content of 52.5 vol.%. The amount added in the first and second batches was 15% and 15% of the total mass of the ceramic mixed powder, respectively, and the amount added in the last two batches was 30% and 40% of the total mass of the ceramic mixed powder, respectively; the mass ratio of raw material powder to grinding balls was 1:2.5. The slurry is then filtered and a solution of tetramethylethylenediamine catalyst and an initiator, ammonium persulfate, are added sequentially. The initiator is used at a concentration of 0.12 wt.% of the ceramic powder mixture. The mass ratio of catalyst to acrylamide is 1:10. Once the mixture is thoroughly mixed at a stirring speed of 55 r / min, the next step, molding, can be performed.

[0063] (3) Pour the mixed slurry into the glass mold. After the slurry is filled, push the glass cover along the edge of the mold to cover it. Place it in a constant temperature and humidity box at 40 ℃ and 78% for 3 h / g to dry. After drying, place the demoulded green blank in an alumina crucible for sintering. The sintering system is: sintering from room temperature to 910 o C, heating rate is 0.4℃ / min. o C, keep warm for 8h, then cool to 200℃ at a rate of 1.5℃ / min, and then cool naturally to room temperature to obtain a ceramic green body.

[0064] (4) The ceramic blank is sintered in a muffle furnace or a tube furnace in a nitrogen atmosphere at room temperature to 900 o The sintering rate at C is 0.4℃ / min.o C-1450 o The sintering rate at 1450°C was 0.9°C / min. o C-1485 o The sintering rate at C is 0.4℃ / min and the holding time is 7h. o The cooling rate from 4 ℃ to room temperature is 4 ℃ / min. The sintered ceramics are anomalous thermal quenching near-infrared fluorescent ceramics.

[0065] (5) The ceramic obtained in step (4) is mechanically thinned to a thickness of 1.0 mm to obtain a fluorescent ceramic for high-power near-infrared imaging and detection. See the actual picture for details. Figure 1 (Ceramic of Example 3) is a light green anomalous thermal quenching near-infrared fluorescent ceramic.

[0066] The valence state of the luminescent center ion in the prepared near-infrared fluorescent ceramic is +3. The ceramic has a garnet phase structure (see Appendix Figure 3 ), the excitation peak of the ceramic is 450nm, the half-height width is 120nm, and at 150 o The luminous intensity at 200°C is 115% of the room temperature. o The luminescence intensity at 40°C is 140% of that at room temperature. When excited by an excitation source with a wavelength of 460 nm, the emission wavelength is between 650 nm and 900 nm.

[0067] Implementation of counterexample 1 (comparative example 1): (Lu 0.35 Y 0.64 Sc 0.01 )3(Sc 0.84 Al 0.15 Cr 0.01 )2Al3O 12 Preparation of near-infrared fluorescent ceramics

[0068] (1) Set the target product (Lu 0.35 Y 0.64 Sc 0.01 )3(Sc 0.84 Al 0.15 Cr 0.01 )2Al3O 12Lutetium oxide, yttrium oxide, scandium oxide, aluminum oxide, and chromium trioxide were weighed as raw material powders according to the stoichiometric ratios of the elements in the above chemical formula. The raw material powders, ceramic matrix microenvironment modifiers, aluminum oxide grinding balls, and alcohol were mixed in a specific proportion and ball-milled at a speed of 60 r / min for 24 hours. The mixed ceramic powder was dried and sieved to obtain the final product. The divalent matrix microenvironment modifiers (calcium carbonate and magnesium oxide) were added in an amount of 5wt% of the mass of the chromium trioxide, and the tetravalent matrix microenvironment modifiers (zirconia, silicon dioxide, and hafnium dioxide) were added in an amount of 10wt% of the mass of the chromium trioxide. The mass ratio of aluminum oxide grinding balls to raw material powders was 1.2:4, and the amount of alcohol was 1.8 times the mass of the raw material powders.

[0069] (2) The dispersant ammonium citrate, the pH regulator tetramethylammonium hydroxide, the monomer acrylamide, the crosslinking agent, and deionized water are mixed to prepare a premix; wherein the amount of ammonium citrate is 0.1 wt% of the total mass of the ceramic mixed powder, the amount of tetramethylammonium hydroxide is 0.5 wt% of the total mass of the ceramic mixed powder, the amount of acrylamide is 1 wt% of the total mass of the ceramic mixed powder, and the mass ratio of N,N'-methylenebisacrylamide to acrylamide is 1:5; the ceramic mixed powder is added to the premix in 4 times and ball milled to prepare a gel casting slurry with a solid content of 52 vol.%. The amount of the first and second additions is 10% and 10% of the total mass of the ceramic mixed powder, respectively, and the amount of the last two additions is 40% and 40% of the mass of the ceramic mixed powder, respectively; the mass ratio of the ceramic mixed powder to the grinding ball is 1:2. The slurry is then filtered out, and the catalyst tetramethylethylenediamine solution and the initiator ammonium persulfate solution are added in sequence, and the amount of the initiator is 0.15 wt.% of the ceramic mixed powder. The mass ratio of the catalyst to acrylamide is 1:8; after stirring and mixing evenly at a stirring speed of 50 r / min, the next molding operation can be carried out.

[0070] (3) Pour the slurry mixed evenly in step (2) into a glass mold. After the slurry is filled, push the glass cover plate along the edge of the mold to cover it. Place it in a constant temperature and humidity box at a temperature of 38°C and a humidity of 75% to dry for 2 h / g. After drying, place the demoulded blank in an alumina crucible for sintering. The sintering system is: sintering from room temperature to 910 o C, the heating rate is 0.25 ℃ / min. o C, keep it warm for 6 h, then cool it to 200 C at a rate of 1 C / min, and then cool it naturally to room temperature to obtain a ceramic green body.

[0071] (4) The ceramic blank is sintered in a muffle furnace or a tube furnace in a nitrogen atmosphere at room temperature to 900 o The sintering rate at C is 0.25℃ / min, 900o C-1450 o The sintering rate at 1450°C was 0.8°C / min. o C-1485 o The sintering rate at 1485°C was 0.25°C / min. o C for 6 hours, then 1485 o The temperature was cooled to room temperature at a rate of 2°C / min. After sintering, the anomalous thermal quenching near-infrared fluorescent ceramic was obtained.

[0072] (5) The ceramic obtained in step (4) is mechanically thinned to a thickness of 1.0 mm to obtain a fluorescent ceramic for high-power near-infrared imaging and detection. Figure 1 The (ceramic of counter-example 1) is a light green anomalous thermally quenched near-infrared fluorescent ceramic.

[0073] The valence states of the luminescent center ions in the near-infrared fluorescent ceramic prepared by implementing Counter Example 1 are +3 and +4. The ceramic has a garnet phase structure (see Appendix Figure 3 ), the excitation peak of the ceramic is 450 nm, the half-height width is 120 nm, and at 150 o The luminous intensity at 200°C is 85% of that at room temperature. o The luminescence intensity at 400 °C is 71% of that at room temperature. When excited by an excitation source with a wavelength of 460 nm, the emission band is between 650 nm and 900 nm.

[0074] Implementation of counterexample 2 (Comparative Example 2): (Lu 0.345 Y 0.6525 Sc 0.0025 )3(Sc 0.8495 Al 0.15 Cr 0.0005 )2Al3O 12 Preparation of near-infrared fluorescent ceramics

[0075] (1) Set the target product (Lu 0.345 Y 0.6525 Sc 0.0025 )3(Sc 0.8495 Al 0.15 Cr 0.0005 )2Al3O 12 Lutetium oxide, yttrium oxide, scandium oxide, aluminum oxide, and chromium oxide were weighed as raw material powders according to the stoichiometric ratios of the elements in the above chemical formula. The raw material powders, alumina grinding balls, and alcohol were mixed in a certain proportion and ball-milled at a speed of 60 r / min for 24 hours. The mixed ceramic powder was dried and sieved. The mass ratio of alumina grinding balls to raw material powders was 1.2:4, and the amount of alcohol used was 1.8 times the mass of the raw material powders.

[0076] (2) The dispersant ammonium citrate, the pH regulator tetramethylammonium hydroxide, the monomer acrylamide, the crosslinking agent, and deionized water are mixed to prepare a premix; wherein the amount of ammonium citrate is 0.1 wt% of the total mass of the ceramic mixed powder, the amount of tetramethylammonium hydroxide is 0.5 wt% of the total mass of the ceramic mixed powder, the amount of acrylamide is 1 wt% of the total mass of the ceramic mixed powder, and the mass ratio of N,N'-methylenebisacrylamide to acrylamide is 1:5; the ceramic mixed powder is added to the premix in 4 times and ball milled to prepare a gel casting slurry with a solid content of 52 vol.%. The amount of the first and second additions is 10% and 10% of the total mass of the ceramic mixed powder, respectively, and the amount of the last two additions is 40% and 40% of the mass of the ceramic mixed powder, respectively; the mass ratio of the ceramic mixed powder to the grinding ball is 1:2. The slurry is then filtered out, and the catalyst tetramethylethylenediamine solution and the initiator ammonium persulfate solution are added in sequence, and the amount of the initiator is 0.15 wt.% of the ceramic mixed powder. The mass ratio of the catalyst to acrylamide is 1:8; after stirring and mixing evenly at a stirring speed of 50 r / min, the next molding operation can be carried out.

[0077] (3) Pour the slurry mixed evenly in step (2) into a glass mold. After the slurry is filled, push the glass cover plate along the edge of the mold to cover it. Place it in a constant temperature and humidity box at a temperature of 38°C and a humidity of 75% to dry for 2 h / g. After drying, place the demoulded blank in an alumina crucible for sintering. The sintering system is: sintering from room temperature to 910 o C, the heating rate is 0.25 ℃ / min. o C, keep it warm for 6 h, then cool it to 200 C at a rate of 1 C / min, and then cool it naturally to room temperature to obtain a ceramic green body.

[0078] (4) The ceramic blank is sintered in a muffle furnace or a tube furnace in a nitrogen atmosphere at room temperature to 900 o The sintering rate at C is 0.25℃ / min, 900 o C-1450 o The sintering rate at 1450°C was 0.8°C / min. o C-1485 o The sintering rate at 1485°C was 0.25°C / min. o C for 6 hours, then 1485 o The temperature was cooled to room temperature at a rate of 2°C / min. After sintering, the anomalous thermal quenching near-infrared fluorescent ceramic was obtained.

[0079] (5) The ceramic obtained in step (4) is mechanically thinned to a thickness of 1.0 mm to obtain a fluorescent ceramic for high-power near-infrared imaging and detection. See the actual picture for details. Figure 1 The (ceramic of counterexample 2) is a light green anomalous thermally quenched near-infrared fluorescent ceramic.

[0080] In the counter-example 2, no matrix microenvironment modifier was added, i.e. no oxygen vacancies were introduced. The valence states of the luminescent center ions in the prepared near-infrared fluorescent ceramics were +3 and +4. The ceramics had a garnet phase structure (see Appendix Figure 3 ), the excitation peak of the ceramic is 460nm, the half-height width is 120nm, and the o The luminous intensity at 200°C is 80% of that at room temperature. o The luminescence intensity at 400°C is 69% of that at room temperature. When excited by an excitation source with a wavelength of 460 nm, the emission wavelength is between 650 nm and 900 nm.

[0081] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. An abnormal thermal quenching near-infrared fluorescent ceramic, characterized in that: Its chemical formula is: (Lu 0.34+z Y 0.66-y-z Sc y )3(Sc 0.85-x Al 0.15 Cr x )2Al3O 12 ,in y Sc 3+ The mole percentage of dodecahedral sites occupied, x Cr ions occupy the octahedron Sc 3+ The molar percentage of the lattice site, z is the Lu in the dodecahedron 3+ Mole percentage of metering control, 0.0005≤ x ≤0.02, x : y =1:(5-10), x :z=1:(10-20); The ceramics are prepared by using an acrylamide gel casting method combined with solid phase sintering, which specifically includes the following steps: (1) According to the chemical formula (Lu 0.34+z Y 0.66-y-z Sc y )3(Sc 0.85-x Al 0.15 Cr x )2Al3O 12 , 0.0005≤ x ≤0.02, x : y =1:(5-10), x :z=1:(10-20) stoichiometric ratio of each element in which lutetium oxide, yttrium oxide, scandium oxide, aluminum oxide and chromium oxide are weighed as raw material powders respectively, the raw material powders, ceramic matrix microenvironment regulator, aluminum oxide grinding balls and alcohol are mixed in a certain proportion and ball milled, and then dried and sieved to obtain ceramic mixed powder; (2) Preparation of gel casting slurry A premix of ammonium citrate (dispersant), tetramethylammonium hydroxide (pH adjuster), acrylamide (monomer), N,N'-methylenebisacrylamide (crosslinker), and deionized water is prepared. The ceramic powder mixture is added to the premix to prepare a gel casting slurry with a solid content of 52-53 vol%. The ceramic powder mixture is added to the premix in 4-5 batches and ball milled. The slurry is then filtered and a tetramethylethylenediamine solution (catalyst) and an ammonium persulfate solution (initiator) are added in sequence. The mixture is stirred until uniformly mixed before proceeding to the next step of molding. (3) Preparation of ceramic green body The mixed slurry is poured into a glass mold. After the slurry is filled, a glass cover is pushed along the edge of the mold to cover it. The mold is placed in a constant temperature and humidity chamber at a temperature of 38-42°C and a humidity of 75%-80% to dry for 2-3 h / g. The dried and demoulded green body is placed in an alumina crucible for sintering to obtain a ceramic green body. (4) Ceramic sintering The ceramic blank is sintered in a muffle furnace or a tube furnace in a nitrogen atmosphere from room temperature to 900 o The sintering rate at C is 0.25-0.5 ℃ / min, 900 o C-1450 o The sintering rate at 1450°C is 0.8-1.0°C / min. o C-1485 o The sintering rate at 1485°C is 0.25-0.5°C / min. o The holding time at 1485°C is 6-10 h. o When the temperature is lowered to room temperature, the anomalous thermal quenching near-infrared fluorescent ceramics are obtained, and the cooling rate is 2-5 ℃ / min. The ceramic matrix microenvironment regulator consists of a +2-valent matrix microenvironment regulator and a +4-valent matrix microenvironment regulator, wherein the addition amount of the +2-valent matrix microenvironment regulator accounts for 5%-10% of the mass percentage of chromium trioxide, and the addition amount of the +4-valent matrix microenvironment regulator accounts for 10%-15% of the mass percentage of chromium trioxide.

2. The abnormal thermal quenching near-infrared fluorescent ceramic according to claim 1, characterized in that: The abnormal thermal quenching near-infrared fluorescent ceramic is a pure garnet phase, Cr 3+ The crystal field strength of the ions is regulated, the excitation peak of the ceramic is between 430 nm and 460 nm, the half-height width is between 90 nm and 130 nm, the emission band is between 650 nm and 900 nm, and under the excitation of the excitation source with a wavelength of 430 nm to 460 nm, the ceramic is at 150 o The luminous intensity at 200℃ is 105%-165% of the room temperature. o The luminous intensity at 400 °C is 130%-200% of that at room temperature.

3. The method for preparing the abnormal thermal quenching near-infrared fluorescent ceramic according to claim 1 or 2, characterized in that: The ceramics are prepared by using an acrylamide gel casting method combined with solid phase sintering, which specifically includes the following steps: (1) According to the chemical formula (Lu 0.34+z Y 0.66-y-z Sc y )3(Sc 0.85-x Al 0.15 Cr x )2Al3O 12 , 0.0005≤ x ≤0.02, x : y =1:(5-10), x :z=1:(10-20) stoichiometric ratio of each element in which lutetium oxide, yttrium oxide, scandium oxide, aluminum oxide and chromium oxide are weighed as raw material powders respectively, the raw material powders, ceramic matrix microenvironment regulator, aluminum oxide grinding balls and alcohol are mixed in a certain proportion and ball milled, and then dried and sieved to obtain ceramic mixed powder; (2) Preparation of gel casting slurry A premix of ammonium citrate (dispersant), tetramethylammonium hydroxide (pH adjuster), acrylamide (monomer), N,N'-methylenebisacrylamide (crosslinker), and deionized water is prepared. The ceramic powder mixture is added to the premix to prepare a gel casting slurry with a solid content of 52-53 vol%. The ceramic powder mixture is added to the premix in 4-5 batches and ball milled. The slurry is then filtered and a tetramethylethylenediamine solution (catalyst) and an ammonium persulfate solution (initiator) are added in sequence. The mixture is stirred until uniformly mixed before proceeding to the next step of molding. (3) Preparation of ceramic green body The mixed slurry is poured into a glass mold. After the slurry is filled, a glass cover is pushed along the edge of the mold to cover it. The mold is placed in a constant temperature and humidity chamber at a temperature of 38-42°C and a humidity of 75%-80% to dry for 2-3 h / g. The dried and demoulded green body is placed in an alumina crucible for sintering to obtain a ceramic green body. (4) Ceramic sintering The ceramic blank is sintered in a muffle furnace or a tube furnace in a nitrogen atmosphere from room temperature to 900 o The sintering rate at C is 0.25-0.5 ℃ / min, 900 o C-1450 o The sintering rate at 1450°C is 0.8-1.0°C / min. o C-1485 o The sintering rate at 1485°C is 0.25-0.5°C / min. o The holding time at 1485°C is 6-10 h. o When the temperature is lowered to room temperature, the anomalous thermal quenching near-infrared fluorescent ceramics are obtained, and the cooling rate is 2-5 ℃ / min. The ceramic matrix microenvironment regulator consists of a +2-valent matrix microenvironment regulator and a +4-valent matrix microenvironment regulator, wherein the addition amount of the +2-valent matrix microenvironment regulator accounts for 5%-10% of the mass percentage of chromium trioxide, and the addition amount of the +4-valent matrix microenvironment regulator accounts for 10%-15% of the mass percentage of chromium trioxide.

4. The method for preparing the abnormal thermal quenching near-infrared fluorescent ceramic according to claim 3, characterized in that: The +2-valent modifier includes at least one of calcium carbonate and magnesium oxide, and the +4-valent modifier includes at least one of zirconium oxide, silicon dioxide, and hafnium dioxide.

5. The method for preparing the abnormal thermal quenching near-infrared fluorescent ceramic according to claim 3, characterized in that: The rotation speed of the mixing ball mill in the step (1) is 60-110 r / min, and the ball milling time is 24 h-48 h.

6. The method for preparing the abnormal thermal quenching near-infrared fluorescent ceramic according to claim 3, characterized in that: In step (1), the mass ratio of alumina grinding balls to raw material powder is (1.2-1.3):(4-5), and the amount of alcohol used is 1.8-3.6 times the mass of the raw material powder.

7. The method for preparing the abnormal thermal quenching near-infrared fluorescent ceramic according to claim 3, characterized in that: During the ball milling in step (2), the mass ratio of the raw material powder to the grinding balls is 1:(2-3), the amount of the initiator ammonium persulfate solution used is 0.15-0.4wt.% of the ceramic mixed powder, the mass ratio of the catalyst tetramethylethylenediamine solution to acrylamide is 1:(8-12), and the stirring speed is 50 r / min-60 r / min.

8. The method for preparing the abnormal thermal quenching near-infrared fluorescent ceramic according to claim 3, characterized in that: In the step (2), the ceramic mixed powder is added to the premixed liquid for ball milling in 4-5 times, the amount added in the first 1-2 times is 10%-15% of the total mass of the ceramic mixed powder, and the amount added in the next 2-3 times is 25%-40% of the total mass of the ceramic mixed powder.

9. The method for preparing the abnormal thermal quenching near-infrared fluorescent ceramic according to claim 3, characterized in that: The sintering operation in step (3) is as follows: sintering from room temperature to 910 o C, heating rate of 0.25-0.5℃ / min, at 910 o C, keep warm for 6-9h, then cool to 200℃ at a rate of 1-2℃ / min, and then cool naturally to room temperature to obtain a ceramic green body.

10. Application of the anomalous thermal quenching near-infrared fluorescent ceramic according to claim 1 or 2 in the field of high-power near-infrared imaging and detection, characterized in that: The excitation peak of the anomalous thermal quenching near-infrared fluorescent ceramic is between 430 nm and 460 nm, and the half-height width is between 90 nm and 130 nm. After the prepared near-infrared fluorescent ceramic is packaged with an excitation source with an excitation peak of 430 nm to 460 nm, the emission band of the device is between 650 nm and 900 nm, and the ceramic is between 150 nm and 130 nm. o The luminous intensity at 200℃ is 105%-165% of the room temperature. o The luminous intensity at 400 °C is 130%-200% of that at room temperature.

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