Tantalate ceramic material based on lithiation induced phase change as well as preparation method and application of tantalate ceramic material

Abstract

The invention discloses a lithiation induced phase change-based tantalate ceramic material as well as a preparation method and application thereof. The structural formula of the material is ZnTa2O6 and / or (Li < 0.5 > Zn < 0.5 >) TaO < 3 >; znTa2O6 is of a tetragonal phase P42 / mnm structure, and (Li < 0.5 > Zn < 0.5 >) TaO3 is of a trigonal phase R3c structure. The material is prepared by the following steps: fully mixing raw materials including ZnO, Ta2O5 and Li2CO3, putting the mixture into a corundum crucible, and sintering. The material takes ZnTa2O6 as a substrate, under the action of Li < + >, the ceramic material is used for preparing a multifunctional piezoelectric ceramic material, such as a fluorescent material, by controlling the addition amount of Li < + > and inducing phase change in the ceramic material, along with the increase of Li < + >, a tantalate ceramic matrix in the fluorescent material is gradually converted from o-ZTO (cubic phase ZnTa2O6) to pure phase t-ZTO (tetragonal phase ZnTa2O6) until to pure phase LZTO (triclinic phase (Li0. 5Zn0. 5) TaO3), and the material has the advantages of simple process, low cost and high efficiency. Further, the internal quantum efficiency and the light-emitting thermal stability of the fluorescent material are greatly improved.

Description

Technical Field

[0001] The invention relates to a tantalate ceramic material, in particular to a tantalate ceramic material for lithiation-induced phase change and a preparation method and application thereof, belonging to the technical field of piezoelectric ceramics. Background Art

[0002] Tantalate ceramics are a type of wide bandgap semiconductor piezoelectric ceramics, which have important applications in the field of electronic materials. Existing ZnTa2O6 tantalate ceramics are all orthorhombic Pbcn structures, which have good structural stability at room temperature, and because of their piezoelectric and dielectric properties, they are often used to prepare various types of piezoelectric sensors. In addition, tantalate ceramics with Pbcn structures also have good optical properties. After being doped with other fluorescent ions, they can show higher fluorescence efficiency and can be used to prepare near-infrared fluorescent materials. However, it is precisely because the crystal phase structure of tantalate ceramics is too single that it has great limitations in specific application fields and cannot meet the technical requirements of multifunctional piezoelectric ceramic materials.

[0003] The existing technology mostly improves the physical and chemical properties of tantalate ceramics by doping with a variety of impurity ions. The Chinese patent (CN102765939B) discloses a microwave dielectric ceramic with low dielectric constant loss. The material is obtained by adding Sb2O3 to ZnTa2O6 ceramics to obtain a multiphase microwave dielectric ceramic. A microwave dielectric ceramic material with a medium dielectric constant, a high quality factor and a stable temperature coefficient at a relatively low sintering temperature is provided. Its sintering temperature is 1225-1275°C, the dielectric constant is 25-29, the quality factor is 65,000-120,000GHz, and the resonant frequency temperature coefficient is 23-28×10 -6 / ℃. The preparation process of the microwave dielectric ceramic material is simple and pollution-free, and can meet the requirements of application in high-performance microwave devices. However, the ZnTa2O6 ceramic in the material is still an orthorhombic Pbcn structure, which leads to limited performance improvement and the inability to change the physical and chemical properties of the ZnTa2O6 ceramic in a directional manner.

[0004] Due to the problem that the crystal phase structure of ZnTa2O6 ceramics is too single, the market is in urgent need of new pure phase ZnTa2O6 ceramics to meet the specific performance requirements of multifunctional piezoelectric ceramic materials. Summary of the invention

[0005] In view of the problems existing in the prior art, the first object of the present invention is to provide a tantalate ceramic material based on lithiation-induced phase transition. The ceramic material is based on ZnTa2O6 and is + Under the action of Li + The addition amount of Li +As the orthorhombic ZnTa2O6 increases, it gradually transforms into the tetragonal P42 / mnm structure ZnTa2O6 and the trigonal R3c structure (Li 0.5 Zn 0.5 )TaO3, and when Li + With Zn 2+ When the stoichiometric ratio is greater than or equal to 0.7, a pure phase of the rhombohedral R3c structure (Li 0.5 Zn 0.5 )TaO3.

[0006] The second object of the present invention is to provide a method for preparing tantalate ceramic materials based on lithiation-induced phase change. The method is based on the principle of high-temperature solid-phase reaction and adopts a one-pot method to prepare tantalate ceramic materials. By controlling the addition ratio of each raw material component, the crystal phase structure of the obtained tantalate ceramic material is directionally controlled. The method is simple to operate, low in cost, and has a high degree of orientation of the crystal phase of the product, which can meet the requirements of industrial continuous production.

[0007] The third object of the present invention is to provide an application of tantalate ceramic materials based on lithium induced phase change, which is used to prepare multifunctional piezoelectric ceramic materials. Based on the advantages of the above lithium induced phase change tantalate ceramic materials, they can be used to prepare multifunctional piezoelectric ceramic materials; wherein, when the obtained multifunctional piezoelectric ceramic material is a near-infrared fluorescent material, as Li + With the increase of , the tantalate ceramic matrix in the material is gradually transformed from o-ZTO to pure phase t-ZTO and finally to pure phase LZTO, thereby greatly improving the internal quantum efficiency of the fluorescent material and its luminescent thermal stability.

[0008] In order to achieve the above technical objectives, the present invention provides a method for preparing tantalate ceramic materials based on lithiation-induced phase change, wherein raw materials including ZnO, Ta2O5 and Li2CO3 are fully mixed and placed in a corundum crucible for sintering; the stoichiometric ratio of ZnO to Ta2O5 is 0.9-1.1:0.9-1.1; the stoichiometric ratio of Li2CO3 to ZnO ... + With Zn 2+ The stoichiometric ratio is 0.01~1.

[0009] The present invention strictly controls the ratio between the raw material components, thereby controlling the crystal phase structure of the obtained tantalate ceramic material. + In the case of induction, ZnTa2O6 ceramics are orthorhombic ZnTa2O6. + As the orthorhombic ZnTa2O6 increases, it gradually transforms into the tetragonal P42 / mnm structure ZnTa2O6 and the trigonal R3c structure (Li 0.5 Zn 0.5 )TaO3, making the material exhibit different physical and chemical properties.

[0010] As a preferred solution, the sintering process is: first, heating from room temperature to 900°C at 10°C / min, then heating from 900°C to 1300-1400°C at 3°C / min, keeping the temperature for 5-8h, and then cooling to room temperature with the furnace.

[0011] The present invention also provides a tantalate ceramic material based on lithiation-induced phase change, wherein the structural formula of the ceramic material is ZnTa2O6 and / or (Li 0.5 Zn 0.5 )TaO3; the ZnTa2O6 is a tetragonal P42 / mnm structure, denoted as t-ZTO, (Li 0.5 Zn 0.5 )TaO3 is a rhombohedral R3c structure, denoted as LZTO.

[0012] As a preferred solution, when the stoichiometric ratio of Li2CO3 to ZnO is 0.01-0.40, the ceramic material is a mixture of orthorhombic ZnTa2O6 and tetragonal P42 / mnm structured ZnTa2O6, wherein the orthorhombic Pbcn structured ZnTa2O6 is denoted as o-ZTO.

[0013] As a preferred solution, when the stoichiometric ratio of Li2CO3 to ZnO is 0.40 to 0.70, the ceramic material is mainly tetragonal P42 / mnm structure ZnTa2O6 and trigonal R3c structure (Li 0.5 Zn 0.5 )TaO3 mixture.

[0014] As a preferred solution, when the stoichiometric ratio of Li2CO3 to ZnO is greater than 0.7, the ceramic material is a rhombohedral R3c structure (Li 0.5 Zn 0.5 )TaO3.

[0015] The present invention also provides an application of tantalate ceramic materials based on lithiation-induced phase change, characterized in that: it is used to prepare multifunctional piezoelectric ceramic materials; the multifunctional piezoelectric ceramic material is at least one of ferroelectric materials, dielectric materials, catalytic materials, fluorescent materials and energy storage materials.

[0016] As a preferred solution, when the multifunctional piezoelectric ceramic material is a near-infrared fluorescent material in a fluorescent material, its general structural formula is ZnTa (2-x / 2) O6:xCr 3+ @yLi + , denoted as ZTO:xCr 3+ , where 0≤x≤0.10, 0<y<1.

[0017] As a preferred solution, the structural formula of the near-infrared fluorescent material is ZnTa 1.96 O6:0.08Cr 3+ @yLi + , wherein, when 0≤y<0.05, the tantalate ceramic matrix in the obtained fluorescent material is a mixture of o-ZTO and t-ZTO, when y=0.05, the tantalate ceramic matrix in the obtained fluorescent material is t-ZTO, when 0.05≤y<0.7, the tantalate ceramic matrix in the obtained fluorescent material is a mixture of o-ZTO, t-ZTO and LZTO, and when 0.7≤y, the tantalate ceramic matrix in the obtained fluorescent material is LZTO.

[0018] As a preferred solution, the preparation process of the near-infrared fluorescent material is: ZnO, Ta2O5, Li2CO3 and Cr2O3 are fully mixed and placed in a corundum crucible, compacted, and then heated from room temperature to 900°C at 10°C / min, and then heated from 900°C to 1300-1400°C at 3°C / min, kept warm for 5-8h, and then cooled to room temperature with the furnace.

[0019] The tetragonal P42 / mnm structure ZnTa2O6 prepared in the present invention has the same structure as MgTa2O6, while the trigonal R3c structure (Li 0.5 Zn 0.5 )TaO3 has exactly the same structure as LiTaO3. Due to the change in the structure of the matrix material, the performance of the near-infrared fluorescent material has also changed accordingly. After testing, when the matrix material is pure phase t-ZTO, its internal quantum efficiency is increased by 112% compared with o-ZTO. When the matrix material is pure phase LZTO, its internal quantum efficiency is increased by 140% compared with o-ZTO. At 100℃, the luminescence integrated intensity values ​​of the three fluorescent materials are maintained at 20.7%, 35.8% and 42.6% of their initial values ​​at 25℃, respectively, proving that the tetragonal P42 / mnm structure ZnTa2O6 and the trigonal R3c structure (Li 0.5 Zn 0.5 )TaO3 can give fluorescent materials higher thermal stability.

[0020] Compared with the prior art, the beneficial technical effects of the technical solution of the present invention are:

[0021] 1) The tantalate ceramic material provided by the present invention is based on ZnTa2O6 and is + Under the action of Li + The addition amount of Li +As the orthorhombic ZnTa2O6 increases, it gradually transforms into the tetragonal P42 / mnm structure ZnTa2O6 and the trigonal R3c structure (Li 0.5 Zn 0.5 )TaO3, and when Li + With Zn 2+ When the stoichiometric ratio is greater than or equal to 0.7, a pure phase of the R3c structure (Li 0.5 Zn 0.5 )TaO3.

[0022] 2) The preparation method provided by the present invention is based on the principle of high-temperature solid-phase reaction and adopts a one-pot method to prepare tantalate ceramic materials. By controlling the addition ratio of each raw material component, the crystal phase structure of the obtained tantalate ceramic material is directionally controlled. This method is simple to operate, low in cost, and has a high degree of orientation of the crystal phase of the product, which can meet the requirements of industrial continuous production.

[0023] 3) In the technical solution provided by the present invention, based on the advantages of the above-mentioned lithium-induced phase change tantalate ceramic material, it can be used to prepare a multifunctional piezoelectric ceramic material; wherein, when the obtained multifunctional piezoelectric ceramic material is a near-infrared fluorescent material, as Li + With the increase of , the tantalate ceramic matrix in the material is gradually transformed from o-ZTO to pure phase t-ZTO and finally to pure phase LZTO, thereby greatly improving the internal quantum efficiency of the fluorescent material and its luminescent thermal stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The different Li in Examples 1 to 5 of the present invention + Content lithiation induced ZnTa2O6:yLi + XRD pattern of phase transition;

[0025] Figure 2 The near-infrared phosphor ZnTa of the present invention (2-x / 2) O6:xCr 3+ (ZTO:xCr 3+ )’s XRD pattern;

[0026] Figure 3 The near-infrared phosphor ZnTa of the present invention 1.96 O6:0.08Cr 3+ @yLi + XRD pattern of

[0027] Figure 4 The near-infrared phosphor t-ZTO:0.08Cr of the present invention 3+ @0.05Li + FESEM image of (P42 / mnm) and its FESEM-EDS mapping image;

[0028] Figure 5 The near-infrared phosphor t-ZTO:0.08Cr of the present invention 3+ @0.05Li + and LZTO:0.08Cr 3+ @0.7Li + Schematic diagram of the structure;

[0029] in, Figure 5 (a) is the crystal structure diagram of LiTaO3 and the [TaO6] octahedral skeleton diagram left after Li is removed from LiTaO3. Figure 5 (b) LZTO:0.08Cr 3+ @0.7Li + , XRD patterns of LiTaO3 and [TaO6] octahedral frameworks, Figure 5 (c) LZTO:0.08Cr 3+ @0.7Li + FESEM image and FESEM-EDS mapping image, Figure 5 (d) t-ZTO:0.08Cr 3+ @0.05Li + HRTEM image of Figure 5 (e) t-ZTO:0.08Cr 3+ @0.05Li + The electron diffraction pattern of Figure 5 (f) LZTO:0.08Cr 3+ @0.7Li + HRTEM image of Figure 5 (g) LZTO:0.08Cr 3+ @0.7Li + Electron diffraction pattern of

[0030] Figure 6 The near-infrared phosphor o-ZTO of the present invention: 0.04Cr 3+ 、t-ZTO:0.08Cr 3+ @0.05Li + and LZTO:0.08Cr 3+ @0.7Li + XRD patterns and sample photos;

[0031] in, Figure 6 (a) is o-ZTO: 0.04Cr 3+ XRD diagram and sample photos, Figure 6 (b) t-ZTO:0.08Cr 3+ @0.05Li +XRD diagram and sample photos, Figure 6 (c) LZTO:0.08Cr 3+ @0.7Li + XRD patterns and sample photos;

[0032] Figure 7 The near-infrared phosphor o-ZTO of the present invention: 0.04Cr 3+ 、t-ZTO:0.08Cr 3+ @0.05Li + and LZTO:0.08Cr 3+ @0.7Li + Preliminary performance test diagram of

[0033] in, Figure 7 (a) is o-ZTO: 0.04Cr 3+ 、t-ZTO:0.08Cr 3+ @0.05Li + and LZTO:0.08Cr 3+ @0.7Li + Diffuse reflectance absorption spectrum of Figure 7 (b) is o-ZTO: 0.04Cr 3+ 、t-ZTO:0.08Cr 3+ @0.05Li + and LZTO:0.08Cr 3 + @0.7Li + Excitation and emission spectra of

[0034] Figure 8 The near-infrared phosphor ZnTa of the present invention 1.96 O6:0.08Cr 3+ @yLi + Fluorescence performance test chart;

[0035] Figure 8 (a) is ZnTa 1.96 O6:0.08Cr 3+ @yLi + The excitation spectrum of Figure 8 (b) ZnTa 1.96 O6:0.08Cr 3+ @yLi + and emission spectra, Figure 8 (c) ZnTa 1.96 O6:0.08Cr 3+ @yLi + The integrated luminous intensity diagram of

[0036] Fig. 9The near-infrared phosphor o-ZTO of the present invention: 0.04Cr 3+ 、t-ZTO:0.08Cr 3+ @0.05Li + and LZTO:0.08Cr 3+ @0.7Li + Thermal stability analysis diagram of

[0037] in, Fig. 9 (a) is o-ZTO: 0.04Cr 3+ 2D thermal stability spectrum of Fig. 9 (b) t-ZTO:0.08Cr 3+ @0.05Li + 2D thermal stability spectrum of Fig. 9 (c) LZTO:0.08Cr 3+ @0.7Li + 2D thermal stability spectrum of Fig. 9 (d) is o-ZTO: 0.04Cr 3+ 、t-ZTO:0.08Cr 3+ @0.05Li + and LZTO:0.08Cr 3+ @0.7Li + High temperature integrated luminous intensity diagram. DETAILED DESCRIPTION

[0038] In order to facilitate the understanding of the present invention, the present invention will be described in more comprehensive and detailed manner in conjunction with the accompanying drawings and preferred embodiments of the specification. It should be noted that the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Example 1

[0040] ZnO, Ta2O5 and Li2CO3 were prepared according to ZnTa2O6:yLi + (ZTO:yLi + ) in a stoichiometric ratio, and then weighed and mixed thoroughly, transferred to a corundum crucible, compacted, and then heated from room temperature to 900°C at 10°C / min, and then heated from 900°C to 1350°C at 3°C / min, sintered for 6h, and then cooled to room temperature in the furnace to obtain the product. Wherein, y = 0.07.

[0041] Example 2

[0042] This embodiment is exactly the same as the embodiment 1, except that y=0.35.

[0043] Example 3

[0044] This embodiment is exactly the same as the embodiment 1, except that y=0.40.

[0045] Example 4

[0046] This embodiment is exactly the same as the embodiment 1, except that y=0.50.

[0047] Example 5

[0048] This embodiment is exactly the same as the embodiment 1, except that y=0.70.

[0049] The materials obtained in Examples 1 to 5 were subjected to XRD testing, and the results are as follows: Figure 1 As shown, the material contains Li + The results of the content changes of different phases induced by phase change of the material are shown in Table 1.

[0050] Table 1

[0051]

[0052] Note: o-ZTO is orthorhombic ZnTa2O6, t-ZTO is tetragonal P42 / mnm structure ZnTa2O6, LZTO is trigonal R3c structure (Li 0.5 Zn 0.5 )TaO3.

[0053] pass Figure 1 As shown in Table 1, when Li is not added + When Li + When the dosage gradually increases to y = 0.35, the ceramic material becomes a mixed phase of o-ZTO and t-ZTO; when Li + When the dosage increases to y = 0.40, it further evolves into a three-phase mixture of o-ZTO, t-ZTO and LZTO, and as Li + As the dosage increases, the content of o-ZTO and t-ZTO decreases gradually, and the content of LZTO increases gradually. + When the dosage increases to y = 0.70, the ceramic material is completely transformed into pure phase LZTO and no longer contains other impurities. Figure 1It can also be seen that since t-ZTO and LZTO are two new structures of tantalate ceramics, there are no standard cards for them in XRD. However, by comparison, it can be found that t-ZTO has exactly the same structure as MgTa2O6 (space group is P42 / mnm, PDF card number is 84-1679), and LZTO has exactly the same structure as LiTaO3, which also proves that t-ZTO is a tetragonal P42 / mnm structure and LZTO is a trigonal R3c structure.

[0054] Since t-ZTO and LZTO are completely different from the tantalate crystal phase structures in the prior art, the physicochemical properties they exhibit are also completely different. A series of multifunctional piezoelectric ceramic materials can be prepared using the above-mentioned tantalate ceramics as a matrix. The present invention takes the fluorescent material in the multifunctional piezoelectric ceramic material as an example to specifically illustrate the excellent performance of the lithiation-induced phase change tantalate ceramic material. It should be noted that the following description is only to facilitate those skilled in the art to better understand the physicochemical properties of the material rather than to limit the application field of the material. Any conversion and application based on the specific structure of the material without creative labor shall be deemed to be within the scope of protection claimed by the present invention.

[0055] In order to better illustrate the application advantages of the above-mentioned lithiation-induced phase change tantalate ceramic materials, the present invention firstly analyzes the ZnTa (2-x / 2) O6:xCr 3+ XRD test was carried out and the results are as follows Figure 2 The results of different phase contents in the material are shown in Table 2.

[0056] Table 2

[0057]

[0058] pass Figure 2 As shown in Table 2, when there is no Li + When induced, the fluorescent material follows Cr 3+ When the doping amount increases, that is, when x increases to 0.04, the trace phase Ta2O5 in the tantalate ceramic matrix disappears, and pure phase o-ZTO is obtained. 3+ When the doping amount increases further, a mixed phase of o-ZTO and t-ZTO appears. 3+ When the dosage is 0.04, it can induce the formation of pure phase o-ZTO, but further increase of Cr 3+ When the amount is too small, it cannot induce the formation of LZTO phase, but can only induce the formation of t-ZTO phase, and pure phase t-ZTO cannot be obtained.

[0059] The present invention adopts lithiation-induced phase change tantalate ceramic material as the matrix to prepare a series of near-infrared fluorescent materials, and the process is as follows: ZnO, Ta2O5, Li2CO3 and Cr2O3 are reacted according to ZnTa 1.96 O6:0.08Cr 3+ @yLi + The stoichiometric ratio is weighed and fully mixed, transferred to a corundum crucible, compacted, and then heated from room temperature to 900°C at 10°C / min, then heated from 900°C to 1350°C at 3°C / min, sintered for 6h, and then cooled to room temperature with the furnace to obtain, wherein 0<y<1.

[0060] ZnTa 1.96 O6:0.08Cr 3+ @yLi + XRD test was performed, and the results were as follows Figure 3 The results of different phase contents in the material are shown in Table 3.

[0061] Table 3

[0062]

[0063] pass Figure 3 As shown in Table 3, when Li is not added + When Li + When y = 0.03, the relative content of t-ZTO phase reaches 99.29%. + When the dosage of Li continued to increase to y = 0.05, the tantalate matrix was completely transformed into t-ZTO pure phase; further, when Li + When the dosage continues to increase to y>0.05, the tantalate matrix becomes a three-phase mixture of o-ZTO, t-ZTO and LZTO, and as Li + With the increase of dosage, the relative content of LZTO phase gradually increases until y=0.7, when the tantalate matrix is ​​completely transformed into pure LZTO phase.

[0064] To verify t-ZTO:0.08Cr 3+ @0.05Li + and LZTO:0.08Cr 3+ @0.7Li + The present invention also performs ICP-OES component analysis on the above two fluorescent materials respectively, and the results are shown in Table 4.

[0065] Table 4

[0066]

[0067] Note: *A: t-ZTO:0.08Cr 3+ ,0.05Li + (P42 / mnm); ^B: LZTO: 0.08Cr 3+ ,0.70Li + (R3c)

[0068] From Table 4, we can see that t-ZTO:0.08Cr 3+ @0.05Li + The chemical formula of t-ZTO matrix is ​​ZnTa2O6, LZTO: 0.08Cr 3+ @0.7Li + The chemical formula of the LZTO matrix is ​​(Li 0.5 Zn 0.5 )TaO3, and Figure 3 This corresponds to the test results in Table 3.

[0069] Furthermore, the present invention also provides t-ZTO:0.08Cr 3+ @0.05Li + and LZTO:0.08Cr 3+ @0.7Li + A series of characterizations were performed on the two fluorescent materials, and the results are as follows Figure 4 and Figure 5 As shown, through Figure 4 and Figure 5 It can be seen that t-ZTO:0.08Cr 3+ @0.05Li + The 101 crystal plane spacing of the fluorescent material is d = 0.425nm, and the 002 crystal plane spacing is d = 0.485nm. Combined with its electron diffraction pattern, it can be fully determined that the tantalate ceramic matrix in the material is a tetragonal phase P42 / mnm structure; the [TaO6] octahedral skeleton left after removing Li from LiTaO3 is exactly the same as the XRD test results of LiTaO3, and the above test results are consistent with LZTO:0.08Cr 3+ @0.7Li + The XRD test results of LZTO: 0.08Cr 3+ @0.7Li + The 110 crystal plane spacing of the fluorescent material is d=0.267nm, and the 012 crystal plane spacing is d=0.387nm. Combined with its electron diffraction pattern, it can be fully determined that the tantalate ceramic matrix in the material is a rhombohedral phase R3c structure.

[0070] After determining the above three pure phase tantalate ceramic matrix phosphor materials o-ZTO: 0.04Cr 3+ 、t-ZTO:0.08Cr 3 +@0.05Li + and LZTO:0.08Cr 3+ @0.7Li + Afterwards, the present invention carried out XRD test and preliminary performance test respectively, and the results are as follows Figure 6 and Figure 7 As shown. Figure 6 It can be seen that o-ZTO: 0.04Cr 3+ It is an orthorhombic Pbcn structure, pink in color, t-ZTO: 0.08Cr 3+ @0.05Li + It is a tetragonal phase P42 / mnm structure, gray in color, LZTO: 0.08Cr 3+ @0.7Li + It has a trigonal R3c structure and is pea green in color. Figure 7 It can be seen that the luminescence half-widths of the above three fluorescent materials are 199nm, 184nm and 202nm, and the luminescence centers are 949nm, 885nm and 862nm, respectively. This shows that with the increase of Li + As the dosage increases, the luminescence peak gradually blue shifts. 1.96 O6:0.08Cr 3+ @yLi + Press Li + A series of fluorescence performance tests were conducted with different dosages of Figure 8 As shown. Figure 8 It can be clearly seen that with the + The amount of the fluorescent material increases, and the emission peak center wavelength of the fluorescent material changes from o-ZTO: 0.04Cr 3+ The 949nm gradually blue shifts, and as Li + As the amount of Cr increases, the luminescence properties of the fluorescent materials also change. Among them, o-ZTO: 0.04Cr 3+ The internal quantum efficiency of the fluorescent material is 11.8%, t-ZTO: 0.08Cr 3+ @0.05Li + The internal quantum efficiency of the fluorescent material is 25.0%, which is an increase of 112%. LZTO: 0.08Cr 3+ @0.7Li + The internal quantum efficiency is 28.2%, an increase of 140%; Regarding the integrated luminous intensity of the material, t-ZTO:0.08Cr 3+ @0.05Li + The integrated luminous intensity of o-ZTO:0.04Cr 3+ 162.8%, LZTO:0.08Cr 3+ @0.7Li+ The integrated luminous intensity of o-ZTO:0.04Cr 3+ 248.1%, t-ZTO:0.08Cr 3+ @0.05Li + 132.5%, which also shows that the luminous efficiency of the above fluorescent materials is not completely reduced with the increase of Li + The increase is not due to the increase of, but due to the change of the crystal phase structure of t-ZTO and LZTO matrix, which directly enhances the luminescence efficiency of the material.

[0071] After confirming that t-ZTO and LZTO matrices have a direct impact on the luminescent properties of fluorescent materials, the present invention also conducted thermal stability analysis on three pure phase tantalate ceramic matrix fluorescent materials. The results are as follows: Fig. 9 As shown. Fig. 9 It can be seen that the luminescence intensity of the three fluorescent materials decreases with the increase of temperature. At 100°C, the integrated luminescence intensity values ​​of the three fluorescent materials remain at 20.7%, 35.8% and 42.6% of their initial values ​​at 25°C, respectively. This also shows that the phase structure evolution of the tantalate ceramic matrix from o-ZTO (Pbcn) phase → t-ZTO (P42 / mnm) phase → LZTO (R3c) phase gradually improves the thermal stability of the material, which can give the material more excellent thermal stability.

Claims

1. A method for preparing a tantalate ceramic material based on lithiation-induced phase change, characterized in that: The raw materials including ZnO, Ta2O5 and Li2CO3 are fully mixed and placed in a corundum crucible and sintered to obtain the product; the stoichiometric ratio of ZnO to Ta2O5 is 0.9-1.1:0.9-1.1; the stoichiometric ratio of Li2CO3 to ZnO ... + With Zn 2+ The stoichiometric ratio is 0.01~1.

2. The method for preparing a tantalate ceramic material based on lithiation-induced phase transition according to claim 1, characterized in that: The sintering process is as follows: first, heating from room temperature to 900° C. at 10° C. / min, then heating from 900° C. to 1300-1400° C. at 3° C. / min, keeping the temperature for 5-8 hours, and then cooling to room temperature in the furnace.

3. The tantalate ceramic material based on lithiation-induced phase transition according to claim 1 or 2, characterized in that: The structural formula of the ceramic material is ZnTa2O6 and / or (Li 0.5 Zn 0.5 )TaO3; the ZnTa2O6 is a tetragonal P42 / mnm structure, denoted as t-ZTO, (Li 0.5 Zn 0.5 )TaO3 is a rhombohedral R3c structure, denoted as LZTO.

4. The tantalate ceramic material based on lithiation-induced phase transition according to claim 3, characterized in that: When the stoichiometric ratio of Li2CO3 to ZnO is 0.01 to 0.40, the ceramic material is a mixture of orthorhombic phase Pbcn structure ZnTa2O6 and tetragonal phase P42 / mnm structure ZnTa2O6, wherein the orthorhombic phase Pbcn structure ZnTa2O6 is recorded as o-ZTO.

5. The tantalate ceramic material based on lithiation-induced phase transition according to claim 3, characterized in that: The stoichiometric ratio of Li2CO3 to ZnO is 0.40-0.70, and the ceramic material is mainly tetragonal P42 / mnm structure ZnTa2O6 and rhombohedral R3c structure (Li 0.5 Zn 0.5 )TaO3 mixture.

6. The tantalate ceramic material based on lithiation-induced phase transition according to claim 3, characterized in that: When the stoichiometric ratio of Li2CO3 to ZnO is greater than 0.7, the ceramic material is a rhombohedral R3c structure (Li 0.5 Zn 0.5 )TaO3.

7. The use of the lithiation-induced phase transition tantalate ceramic material according to claim 3, characterized in that: Used to prepare multifunctional piezoelectric ceramic materials; the multifunctional piezoelectric ceramic material is at least one of ferroelectric materials, dielectric materials, catalytic materials, fluorescent materials and energy storage materials.

8. The use of a tantalate ceramic material based on lithiation-induced phase transition according to claim 7, characterized in that: When the multifunctional piezoelectric ceramic material is a near-infrared fluorescent material among fluorescent materials, its general structural formula is ZnTa (2-x / 2) O6:xCr 3+ @yLi + , denoted as ZTO:xCr 3+ , where 0≤x≤0.10, 0<y<1.

9. The use of a tantalate ceramic material based on lithiation-induced phase transition according to claim 8, characterized in that: The structural formula of the near-infrared fluorescent material is ZnTa 1.96 O6:0.08Cr 3+ @yLi + , wherein, when 0≤y<0.05, the tantalate ceramic matrix in the obtained fluorescent material is a mixture of o-ZTO and t-ZTO, when y=0.05, the tantalate ceramic matrix in the obtained fluorescent material is t-ZTO, when 0.05≤y<0.7, the tantalate ceramic matrix in the obtained fluorescent material is a mixture of o-ZTO, t-ZTO and LZTO, and when 0.7≤y, the tantalate ceramic matrix in the obtained fluorescent material is LZTO.

10. The use of a tantalate ceramic material based on lithiation-induced phase transition according to claim 9, characterized in that: The preparation process of the near-infrared fluorescent material is as follows: ZnO, Ta2O5, Li2CO3 and Cr2O3 are fully mixed and placed in a corundum crucible, compacted, and then heated from room temperature to 900°C at 10°C / min, then heated from 900°C to 1300-1400°C at 3°C / min, kept warm for 5-8 hours, and then cooled to room temperature in the furnace.

Images