Novel Thermosensitive Fluorescent Powder, Preparation Method Thereof and Application

Abstract

The present invention discloses a novel temperature-sensitive phosphor with a chemical general formula of M2YNbO6:Pr 3+ (where M = Ca or Sr), using an alkaline earth metal salt (selected from one of calcium salts and strontium salts), yttrium salts, niobium oxides, and praseodymium oxides as raw materials, and formulating according to the molar ratio of the chemical general formula M2YNbO6:Pr 3+ (M = Ca or Sr), grinding evenly and then performing high-temperature sintering, and then naturally cooling to obtain the novel temperature-sensitive phosphor M2YNbO6:Pr 3+ (M = Ca or Sr); the novel temperature-sensitive phosphor disclosed by the present invention has a high temperature measurement sensitivity, its luminescence performance is not affected by the cement hydration process when applied to cement-based materials, the prepared temperature-sensitive cement-based materials have luminescence performance, and the temperature can be calibrated and calculated using the luminescence intensity, enabling non-contact measurement of the temperature of cement-based materials, with a simple measurement method and capable of effectively improving the engineering detection efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of luminescent materials, and particularly relates to a novel temperature-sensitive phosphor, a preparation method thereof and an application thereof. Background Art

[0002] Cement-based materials have good plasticity and can be cast into various shapes, making them the most commonly used materials in the construction industry. With the continuous progress of technology, the application scenarios of cement-based materials have become diversified. To meet the requirements of different scenarios, cement-based materials need to have other auxiliary functions in addition to basic mechanical properties. Therefore, the development and innovative research of cement-based materials are of great importance. Among them, the research and development of novel cement-based materials with temperature-sensitive temperature measurement performance are of great significance for detecting environmental or internal temperature changes of cement-based materials. Currently, the common method for measuring the internal temperature of cement-based materials is to utilize the thermoelectric effect of cement-based materials to convert the temperature change in the structure into a measurable electrical signal. When measuring, electrical conductivity sheets need to be pasted at both ends of the cement-based materials. The electrical conductivity sheets can only collect temperature data of one section at a time. When it is necessary to detect the temperature of multiple parts of the structure, the entire detection process will become extremely complicated. At the same time, the pasting quality of the electrical conductivity sheets also has a great influence on the detection results. Therefore, it is crucial to develop novel cement-based materials with temperature-sensitive properties to achieve non-contact large-area temperature detection of building structures.

[0003] Compared with electrical signals, visible light is a signal that can be directly observed and detected. There has been research on endowing cement-based materials with luminescent functions. For example, Patent 201210442071.8 prepared a energy storage luminescent concrete by introducing energy storage phosphors into concrete. However, it should be noted that currently, in the research of luminescent concrete, the luminescent function is only used as a decorative function without other functions. Among luminescent materials, the luminescence intensity of some materials can change with temperature. Therefore, using such materials as optical temperature sensors, the temperature change can be calibrated and calculated based on the luminescence intensity. Based on this, if temperature-sensitive phosphors are introduced into cement-based materials and the unique temperature-sensitive luminescence characteristics of the materials are utilized, it will be beneficial to the research and development of novel temperature-sensitive cement-based materials, and the temperature change of cement-based materials can be displayed in the form of visible light, which is conducive to achieving non-contact large-area temperature detection. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a novel temperature-sensitive phosphor, a preparation method thereof and an application thereof in view of the deficiencies of the above-mentioned existing technologies. When the novel temperature-sensitive phosphor is applied to cement-based materials, its luminescence performance is not affected by the cement hydration process. The temperature-sensitive cement-based materials prepared by using it have luminescence performance, and the temperature can be calibrated and calculated based on the luminescence intensity. The temperature of cement-based materials can be measured without contact, and the measurement method is simple, which can effectively improve the engineering detection efficiency.

[0005] The technical solution adopted by the present invention to solve the above-mentioned problems is as follows:

[0006] A novel temperature-sensitive phosphor, characterized in that its chemical general formula is M2YNbO6:Pr 3+ (M = Ca or Sr).

[0007] The preparation method of the above-mentioned novel temperature-sensitive phosphor includes the following steps:

[0008] (1) Using alkaline earth metal salts, yttrium salts, niobium oxides and praseodymium oxides as raw materials, and formulating according to the molar ratio of the chemical general formula M2YNbO6:Pr 3+ (M = Ca or Sr), grinding evenly to obtain a mixture; the alkaline earth metal salt is one of calcium salts and strontium salts;

[0009] (2) Sintering the mixture obtained in step (1) and naturally cooling to obtain M2YNbO6:Pr 3+ (M = Ca or Sr) novel temperature-sensitive phosphor.

[0010] According to the above scheme, the calcium salt is any one of calcium-containing carbonates, nitrates, chlorides, oxides and oxalates.

[0011] According to the above scheme, the strontium salt is any one of strontium-containing carbonates, nitrates, chlorides, oxides and oxalates.

[0012] According to the above scheme, the yttrium salt is any one of yttrium-containing carbonates, nitrates, chlorides, oxides and oxalates.

[0013] According to the above scheme, the niobium oxide is any one of Nb2O5, NbO2 and Nb2O3.

[0014] According to the above scheme, the praseodymium oxide is Pr6O 11 .

[0015] According to the above scheme, the sintering process is divided into two steps: (1) Heating to 500 - 800 °C in an air atmosphere and calcining for 5 - 7 h, naturally cooling and then grinding and mixing evenly to remove the moisture and gas therein; (2) Heating again to 1400 - 1600 °C and calcining for 5 - 7 h, and naturally cooling to obtain the above-mentioned novel temperature-sensitive phosphor.

[0016] The application of the above-mentioned novel temperature-sensitive phosphor in cement-based materials; wherein the above-mentioned novel temperature-sensitive phosphor replaces part of the cement in equal amounts, and the replacement amount is 2% - 8% of the cement mass.

[0017] Compared with the existing technology, the beneficial effects of the present invention are:

[0018] (1) The novel temperature-sensitive phosphor provided by the present invention has different rates of change of emission peak intensities in different wavelength bands with increasing temperature, and can achieve temperature measurement by detecting the ratio of emission peak intensities in different wavelength bands at different temperatures. Moreover, the novel temperature-sensitive phosphor has a high temperature measurement sensitivity.

[0019] (2) When the novel temperature-sensitive phosphor provided by the present invention is applied to cement-based materials, its luminescent properties are not affected by the cement hydration process, and the cement-based materials have the function of optical temperature measurement without affecting the basic properties of the cement-based materials. It can use the luminescence intensity ratio for calibration and temperature calculation, can achieve non-contact measurement of the temperature of cement-based materials, and the measurement method is simple, effectively improving the engineering detection efficiency. Description of the Drawings

[0020] Figure 1 X-ray diffraction patterns of Ca2YNbO6:0.01Pr obtained in Example 1 3+ and Sr2YNbO6:0.01Pr obtained in Example 2 3+

[0021] Figure 2 Emission spectra of Ca2YNbO6:0.01Pr obtained in Example 1 3+ and Sr2YNbO6:0.01Pr obtained in Example 2 3+

[0022] Figure 3 Variable-temperature spectra of Ca2YNbO6:0.01Pr obtained in Example 1 (a); ratio change diagram of 625nm and 660nm emission peaks (b); relationship diagram of absolute sensitivity (Sa) and relative sensitivity (Sr) with temperature function (c). 3+

[0023] Figure 4 Variable-temperature spectra of Sr2YNbO6:0.01Pr obtained in Example 2 (a); ratio change diagram of 625nm and 653nm emission peaks (b); relationship diagram of absolute sensitivity (Sa) and relative sensitivity (Sr) with temperature function (c). 3+ Detailed Embodiments

[0024] The technical solutions of the present invention will be described completely and clearly below in conjunction with the embodiments and the drawings. However, the described embodiments are only some embodiments of the present invention, and all other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0025] ​​​​The calcium carbonate, yttrium oxide, niobium pentoxide, praseodymium hexadecaoxide, and strontium carbonate used in the embodiments of the present invention are all commercially available and have a chemical purity of chemically pure; the cement used is 42.5R ordinary Portland cement and white cement (meeting the requirements of the "General Portland Cement" (GB175-2007) and the "White Portland Cement" (GB / T2015-2017) standards respectively); the sand used is machine-made sand, which is Zone II sand with a fineness modulus of 2.7 - 3.0 and an MB value less than 1.4; the mineral powder used is of S95 grade; the fly ash used is of Grade II; the fiber used is polypropylene fiber with a length of 1 - 3 mm; the water used is ordinary tap water.

[0026] Example 1

[0027] A novel temperature-sensitive phosphor with the chemical general formula Ca2YNbO6:0.01Pr 3+ , and its preparation method specifically includes the following steps:

[0028] According to the chemical formula Ca2YNbO6:0.01Pr 3+ , weigh 3.984 g of calcium carbonate CaCO3, 2.266 g of yttrium oxide Y2O3, 2.658 g of niobium pentoxide Nb2O5, and 0.034 g of praseodymium hexadecaoxide Pr6O 11 respectively, and grind them in an agate mortar for 0.5 h to make them uniformly mixed. Then, pre-sinter the obtained mixture in an air atmosphere. The pre-calcination temperature is 700 °C, and the calcination time is 6 h to remove the moisture and gas in the material. After natural cooling, grind and mix them evenly, and then calcine them in an air atmosphere. The calcination temperature is 1500 °C, and the calcination time is 6 h. After natural cooling, take out the Ca2YNbO6:0.01Pr 3+ novel temperature-sensitive phosphor.

[0029] Example 2

[0030] A novel temperature-sensitive phosphor with the chemical general formula Sr2YNbO6:0.01Pr 3+ , and its preparation method specifically includes the following steps:

[0031] According to the chemical formula Sr2YNbO6:0.01Pr 3+ , weigh 5.856 g of strontium carbonate SrCO3, 2.266 g of yttrium oxide Y2O3, 2.658 g of niobium pentoxide Nb2O5, and praseodymium hexadecaoxide Pr6O 110.034 g was ground in an agate mortar for 0.5 h to make it uniformly mixed. The obtained mixture was pre-sintered in an air atmosphere. The pre-calcination temperature was 700 °C and the calcination time was 6 h to remove the moisture and gas in the material. After natural cooling, it was ground and mixed evenly, and then calcined in an air atmosphere. The calcination temperature was 1500 °C and the calcination time was 6 h. After natural cooling, Sr2YNbO6:0.01Pr was obtained. 3+ Novel temperature-sensitive fluorescent powder.

[0032] At room temperature, the Ca2YNbO6:0.01Pr obtained in Example 1 was tested using an X-ray powder diffractometer (Bruker D8 Advance). 3+ The sample and the Sr2YNbO6:0.01Pr obtained in Example 2 3+ The phase purity of the sample, with the instrument using Cu target Kα radiation, The scanning voltage and current were 40 kV and 40 mA respectively, the scanning range was from 10° to 70°, and the scanning speed was 5° / min.

[0033] The Ca2YNbO6:0.01Pr obtained in Example 1 3+ The sample and the Sr2YNbO6:0.01Pr obtained in Example 2 3+ The X-ray diffraction data diagrams of the samples are as Figure 1 shown. It can be seen from Figure 1 that the X-ray diffraction peaks of the samples prepared in Example 1 and Example 2 can correspond one by one to the diffraction peaks of the standard card, indicating that the Ca2YNbO6:0.01Pr 3+ sample obtained in Example 1 and the Sr2YNbO6:0.01Pr 3+ sample obtained in Example 2 are pure phases.

[0034] The emission spectra of the Ca2YNbO6:0.01Pr obtained in Example 1 at room temperature were tested using a fluorescence spectrometer (Horiba FLUOROMAX-4P). 3+ The sample and the Sr2YNbO6:0.01Pr obtained in Example 2 3+ The sample, with the excitation source being a 150 W xenon lamp and the scanning step being 1 nm.

[0035] The Ca2YNbO6:0.01Pr obtained in Example 1 3+ The sample and the Sr2YNbO6:0.01Pr obtained in Example 2 3+ The emission spectra of the samples are as Figure 2 shown. It can be seen from Figure 2 that under the excitation of 450 nm wavelength, the Ca2YNbO6:0.01Pr obtained in Example 1 3+The emission spectrum of the sample consists of emission peaks located near 492 nm, 534 nm, 625 nm, and 660 nm, corresponding to Pr 3+ ions 3 P0→ 3 H4, 3 P1→ 3 H5, 3 P0→ 3 F2 and 3 P0→ 3 F4 electronic transitions; for the Sr2YNbO6:0.01Pr obtained in Example 2 3+ The emission peaks of the sample are similar to those in Example 1. However, it should be noted that for the Ca2YNbO6:0.01Pr obtained in Example 1 3+ The emission peak at 660 nm, in the Sr2YNbO6:0.01Pr obtained in Example 2 3+ has an emission position of 653 nm. The difference between the two is due to the different ionic radii of Ca 2+ ions and Sr 2+ ions, which leads to a change in the crystal field strength inside the matrix, thus affecting the position of the emission peak.

[0036] Using a fluorescence spectrometer with a temperature controller to test the change of the emission spectrum of the Ca2YNbO6:0.01Pr sample obtained in Example 1 with increasing temperature, and the temperature measurement range is from room temperature 25 °C to 300 °C. 3+ (a) shows the change of the emission spectrum of the Ca2YNbO6:0.01Pr sample obtained in Example 1 with increasing temperature. As can be seen from Figure 3 (a), with the increase of temperature, the intensities of all emission peaks in the system gradually decrease. The reason for this phenomenon is that with the increase of temperature, the probability of non-radiative transitions inside increases, resulting in a decrease in emission intensity. Although the intensity of the emission peak gradually decreases with the increase of temperature, the decreasing rates of different emission peaks are different. As shown in 3+ (b), for the Ca2YNbO6:0.01Pr obtained in Example 1 Figure 3 the decreasing rate of the emission peak at 625 nm is much smaller than that of the emission peak at 660 nm. This different decreasing rate will make the ratio between the two different at different temperatures. Based on this, by measuring the ratio of the intensity of the emission peak at 625 nm and the intensity of the emission peak at 660 nm at different temperatures, the temperature corresponding to this ratio can be deduced inversely. This phenomenon provides a basis for optical temperature measurement. Selecting the two emission peaks at 625 nm and 660 nm for comparison, and calculating and fitting the absolute sensitivity (Sa) and relative sensitivity (Sr) of temperature measurement for the Ca2YNbO6:0.01Pr sample obtained in Example 1 according to formulas (1) to (7), the results are as follows Figure 3 (b), for the Ca2YNbO6:0.01Pr obtained in Example 1 3+ in which the decreasing rate of the emission peak at 625 nm is much smaller than that of the emission peak at 660 nm. This different decreasing rate will make the ratio between the two different at different temperatures. Based on this, by measuring the ratio of the intensity of the emission peak at 625 nm and the intensity of the emission peak at 660 nm at different temperatures, the temperature corresponding to this ratio can be deduced inversely. This phenomenon provides a basis for optical temperature measurement. Selecting the two emission peaks at 625 nm and 660 nm for comparison, and calculating and fitting the absolute sensitivity (Sa) and relative sensitivity (Sr) of temperature measurement for the Ca2YNbO6:0.01Pr sample obtained in Example 1 according to formulas (1) to (7), the results are as follows 3+ for the sample temperature measurement, and the results are as followsFigure 3 as shown in (c).

[0037] I ij = hvA ij N ij (1)

[0038] In formula (1), I ij is the luminescence intensity from a certain i state to the j state; hv is the photon energy; v is the photon frequency; h is Planck's constant; A ij is the spontaneous emission probability; N i is the population of the i state.

[0039] ν = c / λ (2)

[0040] In formula (2), ν is the photon frequency; c is the speed of light; λ is the wavelength. I ij can be transformed into formula (3):

[0041]

[0042] Therefore, the fluorescence intensity ratio FIR based on thermally coupled energy levels can be expressed as:

[0043]

[0044] I U is the emission intensity from the upper coupled energy level to the j state; I L is the emission intensity from the lower coupled energy level to the j state. FIR can be transformed into formula (5):

[0045]

[0046] Based on the above formulas, it is deduced that the absolute sensitivity (Sa) and relative sensitivity (Sr) can be expressed as:

[0047]

[0048]

[0049] According to the spectral data and calculation results, it can be seen that within the test temperature range, for the Ca2YNbO6:0.01Pr 3+ sample obtained in Example 1, the maximum values of the absolute sensitivity (Sa) and relative sensitivity (Sr) are 0.201 K -1 and 5.403% K -1 .

[0050] Similarly, Sr2YNbO6:0.01Pr obtained in Example 2 was tested 3+The emission spectrum of the sample changes with the increase of temperature. The intensity of the emission peak also gradually decreases with the increase of temperature, and the emission peaks of 625nm and 653nm decrease at different speeds. The two emission peaks of 625nm and 653nm are selected as comparisons, and the absolute sensitivity (Sa) and relative sensitivity (Sr) of the temperature measurement of Example 2 are calculated. The results are as follows: Figure 4 As shown in the results, the Sr2YNbO6:0.01Pr 3+ It also has optical temperature sensitivity. Within the test temperature range, the Sr2YNbO6:0.01Pr 3+ The maximum values ​​of the absolute sensitivity (Sa) and relative sensitivity (Sr) of the temperature measurement are 0.231K -1 and 7.504% K -1 .

[0051] Comparative Example 1

[0052] The cement-based composite material was prepared, and the components in the mixture were calculated by weight as follows: 400 parts of silicate cement, 1200 parts of sand, 50 parts of mineral powder, 50 parts of fly ash, 200 parts of water, and 1 part of fiber. After all the above components were mixed, they were stirred in a planetary mixer for 240 seconds to obtain a cement-based composite material with excellent workability, no segregation, and no bleeding. The material was placed in a standard size mold for curing and molding.

[0053] Application Example 1

[0054] The thermosensitive cement-based composite material was prepared. The weight percentage of each component in the mixture was as follows: Ca2YNbO6 prepared in Example 1: 0.01Pr 3+ 10 parts of new thermosensitive phosphor, 390 parts of Portland cement, 1200 parts of sand, 50 parts of mineral powder, 50 parts of fly ash, 200 parts of water, and 1 part of fiber. After mixing all the above components, stir them in a planetary mixer for 240 seconds to obtain a cement-based composite material with excellent workability, no segregation or bleeding, and put it into a standard size mold for curing and molding.

[0055] Application Example 2

[0056] The thermosensitive cement-based composite material was prepared. The weight percentage of each component in the mixture was as follows: Ca2YNbO6 prepared in Example 1: 0.01Pr 3+ 30 parts of new thermosensitive phosphor, 370 parts of Portland cement, 1200 parts of sand, 50 parts of mineral powder, 50 parts of fly ash, 200 parts of water, and 1 part of fiber. After mixing all the above components, stir them in a planetary mixer for 240 seconds to obtain a cement-based composite material with excellent workability, no segregation or bleeding, and put it into a standard size mold for curing and molding.

[0057] Application Example 3

[0058] The thermosensitive cement-based composite material was prepared. The weight percentage of each component in the mixture was as follows: Sr2YNbO6 prepared in Example 2: 0.01Pr 3+ 10 parts of new thermosensitive phosphor, 390 parts of Portland cement, 1200 parts of sand, 50 parts of mineral powder, 50 parts of fly ash, 200 parts of water, and 1 part of fiber. After mixing all the above components, stir them in a planetary mixer for 240 seconds to obtain a cement-based composite material with excellent workability, no segregation or bleeding, and put it into a standard size mold for curing and molding.

[0059] Application Example 4

[0060] The thermosensitive cement-based composite material was prepared. The weight percentage of each component in the mixture was as follows: Sr2YNbO6 prepared in Example 2: 0.01Pr 3+ 30 parts of new thermosensitive phosphor, 370 parts of Portland cement, 1200 parts of sand, 50 parts of mineral powder, 50 parts of fly ash, 200 parts of water, and 1 part of fiber. After mixing all the above components, stir them in a planetary mixer for 240 seconds to obtain a cement-based composite material with excellent workability, no segregation or bleeding, and put it into a standard size mold for curing and molding.

[0061] Application Example 5

[0062] The thermosensitive cement-based composite material was prepared. The weight percentage of each component in the mixture was as follows: Ca2YNbO6 prepared in Example 1: 0.01Pr 3+ 30 parts of new thermosensitive phosphor, 370 parts of white cement, 1200 parts of sand, 50 parts of mineral powder, 50 parts of fly ash, 200 parts of water, and 1 part of fiber. After mixing all the above components, stir them in a planetary mixer for 240 seconds to obtain a cement-based composite material with excellent workability, no segregation or bleeding, and put it into a standard size mold for curing and molding.

[0063] Application Example 6

[0064] The thermosensitive cement-based composite material was prepared. The weight percentage of each component in the mixture was as follows: Sr2YNbO6 prepared in Example 2: 0.01Pr 3+ 30 parts of new thermosensitive phosphor, 370 parts of white cement, 1200 parts of sand, 50 parts of mineral powder, 50 parts of fly ash, 200 parts of water, and 1 part of fiber. After mixing all the above components, stir them in a planetary mixer for 240 seconds to obtain a cement-based composite material with excellent workability, no segregation or bleeding, and put it into a standard size mold for curing and molding.

[0065] The cement-based mortar specimens prepared in Application Examples 1-6 all have luminescent properties. The results show that when the novel temperature-sensitive phosphor is applied to cement-based materials, its luminescent properties are not affected by the cement hydration process. The mechanical properties of the cement-based mortar specimens prepared in Comparative Example 1 and Application Examples 1-6 were tested (GB / T 17671-2021). The flexural strength was tested using a DKZ-5000 type electric flexural testing machine, and the compressive strength was tested using a TYE-300 pressure testing machine. The test results are shown in Table 1. It can be seen from Table 1 that as the curing time increases and the degree of cement hydration improves, the flexural strength and compressive strength of the specimens gradually increase; the doping of the novel temperature-sensitive phosphor will affect the strength of the specimens, resulting in a decrease in the strength of the specimens, but the decrease amplitude is not large, which proves that the doping of the novel temperature-sensitive phosphor has little effect on the mechanical properties.

[0066] Table 1

[0067]

[0068] The variable-temperature spectra of the temperature-sensitive cement-based composites in Application Examples 1-6 were tested, and the maximum values of the absolute sensitivity (Sa) and relative sensitivity (Sr) of the temperature-sensitive cement-based materials in the test temperature range were calculated according to Formulas (1)-(7). The results are shown in Table 2. According to the results, it can be known that the absolute sensitivity (Sa) and relative sensitivity (Sr) can be calculated for the cement-based specimens prepared in Practical Application Examples 1-6. The appearance of the maximum absolute sensitivity and relative sensitivity means that the luminescence intensity of the temperature-sensitive cement-based materials is correlated with the temperature change, realizing the temperature-sensitive temperature measurement function.

[0069] Table 2

[0070]

[0071] In summary, without affecting the basic mechanical properties of the temperature-sensitive cement-based composites, the addition of the novel temperature-sensitive phosphor can endow the prepared temperature-sensitive cement-based composites with the function of optical temperature measurement.

[0072] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and its improvement concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A temperature-sensitive phosphor, characterized in that The chemical general formula is M2YNbO6:Pr 3+ , where M = Sr or Ca.

2. The preparation method of the temperature-sensitive phosphor according to claim 1, characterized in that, Including the following steps: (1) Using alkaline earth metal salts, yttrium salts, niobium oxides, and praseodymium oxides as raw materials, according to the molar ratio of the chemical general formula M2YNbO6:Pr 3+ for proportioning, grinding evenly to obtain a mixture, where M = Sr or Ca; the alkaline earth metal salt is one of calcium salts and strontium salts; (2) Sinter the mixture obtained in step (1) and naturally cool it to obtain M2YNbO6:Pr 3+ temperature-sensitive phosphor, where M = Sr or Ca.

3. The preparation method of the temperature-sensitive phosphor according to claim 2, characterized in that, The calcium salt is any one of calcium-containing carbonates, oxides and oxalates.

4. The preparation method of the temperature-sensitive phosphor according to claim 2, wherein The strontium salt is any one of strontium-containing carbonates, oxides and oxalates.

5. The preparation method of the temperature-sensitive phosphor according to claim 2, characterized in that, The yttrium salt is any one of yttrium-containing carbonates, oxides and oxalates.

6. The preparation method of the temperature-sensitive phosphor according to claim 2, wherein, The niobium oxide is any one of Nb2O5, NbO2 and Nb2O3.

7. The preparation method of the temperature-sensitive phosphor according to claim 2, characterized in that, The praseodymium oxide is Pr6O 11 .

8. The preparation method of the temperature-sensitive phosphor according to claim 2, wherein, The sintering process is divided into two steps: (1) heating to 500-800 °C in an air atmosphere and calcining for 5-7 h, naturally cooling and then grinding and mixing evenly to remove moisture and gas therein; (2) heating again to 1400-1600 °C and calcining for 5-7 h, and naturally cooling to obtain the temperature-sensitive phosphor.

9. Application of the temperature-sensitive phosphor according to claim 1 in a cement-based material.

10. The application according to claim 9, wherein The temperature-sensitive phosphor replaces part of the cement in equal amounts, and the replacement amount is 2%-8% of the mass of the cement.

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