A lithium-based induced phase transition tantalate ceramic material, a preparation method and application thereof

Abstract

This invention discloses a lithium-induced phase change tantalate ceramic material, its preparation method, and its applications. The material has the structural formula ZnTa₂O₆ and / or (Li₂O₆). 0.5 Zn 0.5 TaO3; the ZnTa2O6 is a tetragonal phase P42 / mnm structure, (Li 0.5 Zn 0.5 TaO3 has a trigonal R3c structure. This material is obtained by thoroughly mixing raw materials including ZnO, Ta2O5, and Li2CO3, placing them in a corundum crucible, and then sintering. This material uses ZnTa2O6 as a substrate and Li... + Under the influence of Li, by controlling Li + The addition of certain amounts of Li induces a phase transition within the ceramic material, allowing it to be used to prepare multifunctional piezoelectric ceramic materials, such as fluorescent materials. + With the increase of [unclear], the tantalate ceramic matrix in the fluorescent material gradually transforms from o-ZTO (cubic ZnTa₂O₆) to pure t-ZTO (tetragonal ZnTa₂O₆) and finally to pure LZTO (triclinic ZnTa₂O₆). 0.5 Zn 0.5 (TaO3), thereby significantly improving the internal quantum efficiency and luminescence thermal stability of fluorescent materials.

Description

Technical Field

[0001] This invention relates to a tantalate ceramic material, and more particularly to a lithiation-induced phase change tantalate ceramic material, its preparation method, and its application, belonging to the field of piezoelectric ceramic technology. Background Technology

[0002] Tantalate ceramics are wide-bandgap semiconductor piezoelectric ceramics with important applications in the field of electronic materials. Existing ZnTa₂O₆ tantalate ceramics are all orthorhombic Pbcn structures, exhibiting good structural stability at room temperature. Due to their piezoelectric and dielectric properties, they are commonly used to fabricate various piezoelectric sensors. Furthermore, Pbcn-structured tantalate ceramics possess excellent optical properties; after doping with other fluorescent ions, they can exhibit high fluorescence efficiency and can be used to prepare near-infrared fluorescent materials. However, the overly singular crystal phase structure of tantalate ceramics limits their application in specific fields, failing to meet the technical requirements of multifunctional piezoelectric ceramic materials.

[0003] Existing technologies often improve the physicochemical properties of tantalate ceramics by doping them with various heteroions. Chinese patent (CN102765939B) discloses a microwave dielectric ceramic with low dielectric constant and low loss. This material is obtained by adding Sb₂O₃ to ZnTa₂O₆ ceramic to obtain a multiphase microwave dielectric ceramic. It provides a microwave dielectric ceramic material with moderate dielectric constant, high quality factor, and stable temperature coefficient at a relatively low sintering temperature. Its sintering temperature is 1225–1275℃, dielectric constant is 25–29, quality factor is 65,000–120,000 GHz, and resonant frequency temperature coefficient is 23–28 × 10⁻⁶. -6 / ℃. The preparation process of this microwave dielectric ceramic material is simple and pollution-free, meeting the requirements for application in high-performance microwave devices. However, the ZnTa2O6 ceramic in this material still has an orthorhombic Pbcn structure, which limits its performance improvement and makes it impossible to directionally change the physicochemical properties of ZnTa2O6 ceramic.

[0004] Due to the problem of the overly simplistic crystal phase structure of ZnTa2O6 ceramics, the market urgently needs novel pure-phase ZnTa2O6 ceramics to meet the specific performance requirements of multifunctional piezoelectric ceramic materials. Summary of the Invention

[0005] To address the problems existing in the prior art, the first objective of this invention is to provide a lithium-induced phase change tantalate ceramic material. This ceramic material uses ZnTa₂O₆ as a substrate and... + Under the influence of Li, by controlling Li + The addition of certain substances induces a phase transition within the organism; as Li... +With the increase of [unclear], orthorhombic ZnTa2O6 gradually transforms into tetragonal P42 / mnm structure ZnTa2O6 and trigonal R3c structure (Li [unclear]). 0.5 Zn 0.5 TaO3, and when Li + With Zn 2+ When the stoichiometry is greater than or equal to 0.7, a pure-phase trigonal R3c structure (Li) is obtained. 0.5 Zn 0.5 TaO3.

[0006] The second objective of this invention is to provide a method for preparing tantalate ceramic materials based on lithiation-induced phase change. This method is based on the principle of high-temperature solid-state reaction and uses 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 can be controlled in a directional manner. 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 continuous industrial production.

[0007] The third objective of this invention is to provide an application of lithium-induced phase change tantalate ceramic materials for the preparation of multifunctional piezoelectric ceramic materials. Based on the advantages of 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 gradually transforms from o-ZTO to pure-phase t-ZTO and eventually to pure-phase LZTO, thereby significantly improving the internal quantum efficiency and luminescence thermal stability of the fluorescent material.

[0008] To achieve the above-mentioned technical objectives, this invention provides a method for preparing tantalate ceramic materials based on lithium-induced phase change. The method involves thoroughly mixing raw materials including ZnO, Ta₂O₅, and Li₂CO₃, placing them in an alumina crucible, and sintering to obtain the final product. The stoichiometric ratio of ZnO to Ta₂O₅ is 0.9–1.1:0.9–1.1. The stoichiometric ratio of Li₂CO₃ to ZnO is [missing information - likely a specific ratio]. + With Zn 2+ The stoichiometric ratio is 0.01 to 1.

[0009] This invention controls the crystal phase structure of the resulting tantalate ceramic material by strictly controlling the proportions of each raw material component, in the absence of Li + Under induced conditions, ZnTa₂O₆ ceramics are orthorhombic ZnTa₂O₆, with the influence of Li + With the increase of [unclear], orthorhombic ZnTa2O6 gradually transforms into tetragonal P42 / mnm structure ZnTa2O6 and trigonal R3c structure (Li [unclear]). 0.5 Zn 0.5 TaO3 gives the material different physicochemical properties.

[0010] As a preferred embodiment, the sintering process is as follows: first, the temperature is increased from room temperature to 900℃ at a rate of 10℃ / min, then increased from 900℃ to 1300-1400℃ at a rate of 3℃ / min, held at that temperature for 5-8 hours, and then cooled to room temperature in the furnace to obtain the final product.

[0011] This invention also provides a lithium-induced phase change tantalate ceramic material, wherein the ceramic material has the structural formula ZnTa2O6 and / or (Li 0.5 Zn 0.5 TaO3; the ZnTa2O6 is a tetragonal phase P42 / mnm structure, denoted as t-ZTO, (Li 0.5 Zn 0.5 TaO3 has a trigonal R3c structure, denoted as LZTO.

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

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

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

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

[0016] As a preferred embodiment, when the multifunctional piezoelectric ceramic material is a near-infrared 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 embodiment, the near-infrared fluorescent material has the structural formula 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 embodiment, the near-infrared fluorescent material is prepared as follows: ZnO, Ta2O5, Li2CO3 and Cr2O3 are thoroughly mixed and placed in a corundum crucible, compacted, and then heated from room temperature to 900℃ at 10℃ / min, followed by heating from 900℃ to 1300~1400℃ at 3℃ / min, held at that temperature for 5~8h, and then cooled to room temperature with the furnace to obtain the final product.

[0019] The tetragonal P42 / mnm structure ZnTa2O6 prepared in this invention has the same structure as MgTa2O6, while the trigonal R3c structure (Li 0.5 Zn 0.5 TaO3 has the exact same structure as LiTaO3. Due to the change in the matrix material structure, the performance of the near-infrared fluorescent materials also changed accordingly. Tests showed that when the matrix material was pure-phase t-ZTO, its internal quantum efficiency was increased by 112% compared to o-ZTO; when the matrix material was pure-phase LZTO, its internal quantum efficiency was increased by 140% compared to o-ZTO. Furthermore, at 100℃, the luminescence integral intensity values ​​of the three fluorescent materials remained at 20.7%, 35.8%, and 42.6% of their initial values ​​at 25℃, respectively. This demonstrates the effectiveness of the tetragonal P42 / mnm structure ZnTa2O6 and the trigonal R3c structure (Li... 0.5 Zn 0.5 TaO3 can impart higher thermal stability to fluorescent materials.

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

[0021] 1) The tantalate ceramic material provided by this invention uses ZnTa2O6 as a substrate and is based on Li + Under the influence of Li, by controlling Li + The addition of certain substances induces a phase transition within the organism; as Li... +With the increase of [unclear], orthorhombic ZnTa2O6 gradually transforms into tetragonal P42 / mnm structure ZnTa2O6 and trigonal R3c structure (Li [unclear]). 0.5 Zn 0.5 TaO3, and when Li + With Zn 2+ When the stoichiometry is greater than or equal to 0.7, a pure-phase trigonal R3c structure (Li) is obtained. 0.5 Zn 0.5 TaO3.

[0022] 2) The preparation method provided by this invention is based on the principle of high-temperature solid-state reaction and uses 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 materials can be controlled in a directional manner. 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 continuous industrial production.

[0023] 3) In the technical solution provided by this invention, based on the advantages of the aforementioned lithium-induced phase change tantalate ceramic material, it 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 gradually transforms from o-ZTO to pure-phase t-ZTO and eventually to pure-phase LZTO, thereby significantly improving the internal quantum efficiency and luminescence thermal stability of the fluorescent material. Attached Figure Description

[0024] Figure 1 Different Li in Examples 1-5 of the present invention + Lithification-induced ZnTa2O6:yLi + XRD pattern of phase transition;

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

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

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

[0028] Figure 5 The near-infrared phosphor t-ZTO:0.08Cr of this invention is... 3+ @0.05Li + And LZTO:0.08Cr 3+ @0.7Li + A schematic diagram of the structure;

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

[0030] Figure 6 The near-infrared phosphor o-ZTO:0.04Cr of this invention is... 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 patterns and sample photos, Figure 6 (b) is t-ZTO:0.08Cr 3+ @0.05Li +XRD patterns and sample photos, Figure 6 (c) is LZTO:0.08Cr 3+ @0.7Li + XRD patterns and sample photos;

[0032] Figure 7 The near-infrared phosphor o-ZTO:0.04Cr of this invention is... 3+ t-ZTO:0.08Cr 3+ @0.05Li + And LZTO:0.08Cr 3+ @0.7Li + Preliminary performance test charts;

[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 + The diffuse reflectance absorption spectrum, 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;

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

[0035] Figure 8 (a) is ZnTa 1.96 O6:0.08Cr 3+ @yLi + The excitation spectrum, Figure 8 (b) is ZnTa 1.96 O6:0.08Cr 3+ @yLi + emission spectrum Figure 8 (c) is ZnTa 1.96 O6:0.08Cr 3+ @yLi + The integral luminescence intensity diagram;

[0036] Figure 9The near-infrared phosphor o-ZTO:0.04Cr of this invention is... 3+ t-ZTO:0.08Cr 3+ @0.05Li + And LZTO:0.08Cr 3+ @0.7Li + Thermal stability analysis diagram;

[0037] in, Figure 9 (a) is o-ZTO: 0.04Cr 3+ 2D thermal stability spectrum Figure 9 (b) is t-ZTO:0.08Cr 3+ @0.05Li + 2D thermal stability spectrum, Figure 9 (c) is LZTO:0.08Cr 3+ @0.7Li + 2D thermal stability spectrum, Figure 9 (d) is o-ZTO: 0.04Cr 3+ t-ZTO:0.08Cr 3+ @0.05Li + And LZTO:0.08Cr 3+ @0.7Li + High-temperature integral luminescence intensity diagram. Detailed Implementation

[0038] To facilitate understanding of the present invention, a more comprehensive and detailed description of the invention will be provided below in conjunction with the accompanying drawings and preferred embodiments. It should be noted that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0039] Example 1

[0040] ZnO, Ta2O5, and Li2CO3 were mixed in the ratio ZnTa2O6:yLi + (ZTO:yLi + Weigh out the stoichiometric proportions of the sample, mix thoroughly, transfer to a corundum crucible, compact, and then heat from room temperature to 900℃ at 10℃ / min, followed by heating from 900℃ to 1350℃ at 3℃ / min, sinter for 6 hours, and then cool to room temperature in the furnace to obtain the final product. Where y = 0.07.

[0041] Example 2

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

[0043] Example 3

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

[0045] Example 4

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

[0047] Example 5

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

[0049] The materials obtained in Examples 1-5 were subjected to XRD tests, and the results are as follows: Figure 1 As shown, the material contains Li + The content changes induced phase transitions in the material, resulting in different phase contents, as shown in Table 1.

[0050] Table 1

[0051]

[0052] Note: o-ZTO is orthorhombic ZnTa₂O₆, t-ZTO is tetragonal P₄² / mnm structure ZnTa₂O₆, and LZTO is trigonal R₃c structure (Li₂O₆). 0.5 Zn 0.5 TaO3.

[0053] pass Figure 1 As shown in Table 1, when Li is not added + At that time, the ceramic material mainly consists of o-ZTO and trace amounts of Ta2O5 phase; when Li + When the dosage is gradually increased to y = 0.35, the ceramic material becomes a mixed phase of o-ZTO and t-ZTO; when Li + When the dosage is increased to y = 0.40, it further evolves into a three-phase mixture of o-ZTO, t-ZTO, and LZTO, and with the increase of Li + With increasing dosage, the contents of o-ZTO and t-ZTO gradually decrease, while the content of LZTO gradually increases; when Li + When the dosage is increased to y = 0.70, the ceramic material is completely transformed into pure phase LZTO, no longer containing other impurities. Through... Figure 1It is also known that since t-ZTO and LZTO are two novel structures of tantalate ceramics, there are no standard cards for them in XRD. However, by comparison, it can be found that t-ZTO has the same structure as MgTa2O6 (space group P42 / mnm, PDF card number 84-1679), and LZTO has the same structure as LiTaO3. This also proves that t-ZTO is a tetragonal P42 / mnm structure and LZTO is a trigonal R3c structure.

[0054] Since t-ZTO and LZTO have completely different crystal phase structures from those of tantalates in the prior art, their physicochemical properties are also completely different. Using the above-mentioned tantalate ceramics as a matrix, a series of multifunctional piezoelectric ceramic materials can be prepared. This invention takes fluorescent materials among multifunctional piezoelectric ceramic materials as an example to specifically illustrate the excellent performance of lithium-induced phase change tantalate ceramic materials. It should be noted that the following description is only to help those skilled in the art better understand the physicochemical properties of the material and is not a limitation on the application field of the material. Any uninventive transfer or application based on the specific structure of the material is considered to be within the scope of protection claimed by this invention.

[0055] To better illustrate the application advantages of the aforementioned lithium-induced phase change tantalate ceramic materials, this invention first addresses the existing ZnTa... (2-x / 2) O6:xCr 3+ XRD tests were performed, and the results are as follows: Figure 2 As shown in Table 2, the results of different phase contents in the material are presented.

[0056] Table 2

[0057]

[0058] pass Figure 2 As shown in Table 2, when Li is not present... + During induction, the fluorescent material reacts with Cr 3+ As the doping concentration increases, i.e., x increases to 0.04, the trace phase Ta₂O₅ disappears in the tantalate ceramic matrix, resulting in the pure phase o-ZTO. When Cr... 3+ As the doping concentration further increased, a mixed phase of o-ZTO and t-ZTO appeared. This indicates that Cr... 3+ At a dosage of 0.04, it can induce the formation of pure-phase o-ZTO, but further increases in Cr... 3+ When the dosage is adjusted, it cannot induce the formation of the LZTO phase, but can only induce the formation of the t-ZTO phase, and it is impossible to obtain the pure t-ZTO phase.

[0059] This invention uses lithium-induced phase change tantalate ceramic materials as a matrix to prepare a series of near-infrared fluorescent materials. The process is as follows: ZnO, Ta2O5, Li2CO3 and Cr2O3 are mixed in the order ZnTa 1.96 O6:0.08Cr 3+ @yLi + After weighing the stoichiometric proportions, mix thoroughly, transfer to a corundum crucible, compact, and then heat from room temperature to 900℃ at 10℃ / min, followed by heating from 900℃ to 1350℃ at 3℃ / min, sinter for 6 hours, and then cool to room temperature with the furnace to obtain the product, where 0 < y < 1.

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

[0061] Table 3

[0062]

[0063] pass Figure 3 As shown in Table 3, when Li is not added + At that time, the tantalate matrix in the fluorescent material was a mixture of o-ZTO and t-ZTO phases, and with the Li + With the addition of [unclear], when y = 0.03, the relative content of the t-ZTO phase reaches 99.29%, and when Li [unclear]... + When the amount of tantalum is further increased to y = 0.05, the tantalum matrix is ​​completely transformed into the t-ZTO pure phase; furthermore, when Li + When the amount of Li was further increased to y>0.05, the tantalate matrix became a three-phase mixture of o-ZTO, t-ZTO and LZTO, and with the increase of Li + With increasing dosage, the relative content of the LZTO phase gradually increases until y = 0.7, at which point the tantalate matrix is ​​completely transformed into the pure LZTO phase.

[0064] To verify t-ZTO:0.08Cr 3+ @0.05Li + And LZTO:0.08Cr 3+ @0.7Li + In addition to the chemical formula correspondence, the present invention also performed ICP-OES composition analysis on the two fluorescent materials mentioned above, 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] Table 4 shows that t-ZTO: 0.08Cr 3+ @0.05Li + The chemical formula of the LZTO matrix is ​​ZnTa₂O₆, and LZTO is 0.08Cr. 3+ @0.7Li + The chemical formula of the LZTO matrix is ​​(Li 0.5 Zn 0.5 TaO3, and Figure 3 The results correspond to those in Table 3.

[0069] Furthermore, the present invention also addresses t-ZTO:0.08Cr 3+ @0.05Li + And LZTO:0.08Cr 3+ @0.7Li + The two fluorescent materials underwent a series of characterizations, 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 interplanar spacing d = 0.425 nm for the 101 crystal plane and d = 0.485 nm for the 002 crystal plane in the fluorescent material, combined with its electron diffraction pattern, completely confirms that the tantalate ceramic matrix in this material has a tetragonal P42 / nm structure. The [TaO6] octahedral framework remaining after removing Li from LiTaO3 shows identical XRD results to LiTaO3, and these results are consistent with those of LZTO:0.08Cr. 3+ @0.7Li + The XRD test results were also identical, and LZTO:0.08Cr 3+ @0.7Li + The interplanar spacing of the 110 crystal plane of the fluorescent material is d = 0.267 nm, and the interplanar spacing of the 012 crystal plane is d = 0.387 nm. Combined with its electron diffraction pattern, it can be completely determined that the tantalate ceramic matrix in this material is a trigonal R3c structure.

[0070] After determining the three pure-phase tantalate ceramic matrix fluorescent materials o-ZTO: 0.04Cr 3+ t-ZTO:0.08Cr 3 +@0.05Li + And LZTO:0.08Cr 3+ @0.7Li + Subsequently, the present invention underwent XRD testing and preliminary performance testing, and the results are as follows: Figure 6 and Figure 7 As shown. (Through) Figure 6 It can be seen that o-ZTO: 0.04Cr 3+ It exhibits an orthorhombic Pbcn structure, is pink in color, and has a t-ZTO ratio of 0.08Cr. 3+ @0.05Li + It has a tetragonal P42 / mnm structure, is gray in color, and contains LZTO: 0.08Cr. 3+ @0.7Li + It has a trigonal R3c structure and is pea-green in color. (Through...) Figure 7 It can be seen that the full width at half maximum (FWHM) of the emission of the above three fluorescent materials are 199 nm, 184 nm, and 202 nm, respectively, and the emission centers are 949 nm, 885 nm, and 862 nm, respectively. This indicates that with the increase of Li... + As the dosage of ZnTa increases, the emission peak gradually shifts to blue. To better verify this viewpoint, this invention further investigated ZnTa... 1.96 O6:0.08Cr 3+ @yLi + According to Li + A series of fluorescence performance tests were conducted with different dosages, and the results are as follows: Figure 8 As shown. (Through) Figure 8 It can be clearly seen that, with Li + With the increase in the amount of [unspecified substance], the center wavelength of the emission peak of the fluorescent material changes from o-ZTO: 0.04Cr 3+ The 949nm process gradually exhibits a blue shift, and, with Li + With the increase in the amount of [a specific ingredient] used, the luminescent properties of the fluorescent material also changed. Specifically, o-ZTO: 0.04Cr 3+ The fluorescent material has an internal quantum efficiency of 11.8% and a t-ZTO content of 0.08Cr. 3+ @0.05Li + The internal quantum efficiency of the fluorescent material is 25.0%, an improvement of 112%, LZTO:0.08Cr 3+ @0.7Li + The internal quantum efficiency is 28.2%, an improvement of 140%; regarding the integral luminescence intensity of the material, t-ZTO:0.08Cr 3+ @0.05Li + The integrated luminescence intensity is o-ZTO: 0.04Cr 3+ 162.8%, LZTO: 0.08Cr 3+ @0.7Li+ The integrated luminescence intensity is o-ZTO: 0.04Cr 3+ 248.1%, t-ZTO: 0.08Cr 3+ @0.05Li + The luminescence efficiency of the aforementioned fluorescent materials is 132.5%, which also indicates that the luminescence efficiency does not completely change with the efficiency of Li. + The increase is not due to the increase in luminescence, but rather to the change in the crystal phase structure of the t-ZTO and LZTO matrix, which directly enhances the luminescence efficiency of the material.

[0071] After determining that the t-ZTO and LZTO matrices have a direct impact on the luminescence properties of fluorescent materials, this invention also conducted thermal stability analysis on fluorescent materials based on three pure-phase tantalate ceramic matrices. The results are as follows: Figure 9 As shown. (Through) Figure 9 It can be seen that the luminescence intensity of the three fluorescent materials decreases with increasing temperature. At 100℃, the luminescence integral intensity values ​​of the three fluorescent materials remain at 20.7%, 35.8%, and 42.6% of their initial values ​​at 25℃, respectively. This also indicates 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, thus endowing the material with better thermal stability.

Claims

1. A method for preparing tantalate ceramic materials based on lithiation-induced phase change, characterized in that: The raw materials, including ZnO, Ta2O5, and Li2CO3, are thoroughly mixed and placed in an alumina crucible, then sintered to obtain the final product. The stoichiometric ratio of ZnO to Ta2O5 is 0.9~1.1:0.9~1.

1. The stoichiometric ratio of Li2CO3 to ZnO is as follows: + With Zn 2+ The stoichiometric ratio is 0.35~0.7; The ceramic material has the structural formula ZnTa2O6 and / or (Li) 0.5 Zn 0.5 TaO3; the ZnTa2O6 is a tetragonal phase. P 42 / mnm Structure and / or orthorhombic phase, denoted as t-ZTO / o-ZTO, (Li 0.5 Zn 0.5 TaO3 is a trigonal phase. R 3 c The structure is denoted as LZTO.

2. The method for preparing tantalate ceramic materials based on lithiation-induced phase change according to claim 1, characterized in that: The sintering process is as follows: First, the temperature is increased from room temperature to 900℃ at a rate of 10℃ / min, then increased from 900℃ to 1300~1400℃ at a rate of 3℃ / min, held for 5~8 hours, and then cooled to room temperature in the furnace to obtain the final product.

3. The tantalate ceramic material based on lithiation-induced phase change according to claim 1, characterized in that: When the stoichiometric ratio of Li2CO3 to ZnO is 0.35, the ceramic material is a mixture of o-ZTO and t-ZTO. When the stoichiometric ratio of Li2CO3 to ZnO increases from 0.35 to 0.4, the ceramic material evolves into a three-phase mixture of o-ZTO, t-ZTO and LZTO.

4. The tantalate ceramic material based on lithiation-induced phase change according to claim 1, characterized in that: When the stoichiometric ratio of Li2CO3 to ZnO increases from 0.4 to 0.7, the content of the mixed phase of o-ZTO and t-ZTO in the ceramic material gradually decreases until it is transformed into pure phase LZTO.

5. The tantalate ceramic material based on lithiation-induced phase change according to claim 1, characterized in that: When the stoichiometric ratio of Li₂CO₃ to ZnO is greater than 0.7, the ceramic material is a trigonal phase. R 3 c Structure (Li) 0.5 Zn 0.5 TaO3.

6. The application of the lithium-induced phase change tantalate ceramic material according to claim 1, characterized in that: Used to prepare fluorescent materials.

7. A lithium-induced phase change tantalate ceramic material, characterized in that: The general structural formula of the tantalate ceramic material is ZnTa. 1.96 O6:0.08Cr 3+ @yLi + When 0 ≤ y < 0.05, the tantalate ceramic material consists of orthorhombic ZnTa₂O₆ and tetragonal phases. P 42 / mnm A mixture of ZnTa₂O₆ structures, when y=0.05, results in a tetragonal tantalate ceramic material. P 42 / mnm For ZnTa₂O₆ structures, when 0.05 < y < 0.7, tantalate ceramic materials are orthorhombic ZnTa₂O₆ or tetragonal phases. P 42 / mnm Structure and trigonal phase R 3 c Structure (Li) 0.5 Zn 0.5 When 0.7 = y, the mixture of TaO3 forms a trigonal phase tantalate ceramic material. R 3 c Structure (Li) 0.5 Zn 0.5 TaO3.

8. A lithium-induced phase change tantalate ceramic material according to claim 7, characterized in that: The preparation process of the tantalate ceramic material is as follows: ZnO, Ta2O5, Li2CO3 and Cr2O3 are thoroughly mixed and placed in a corundum crucible, compacted, and then heated from room temperature to 900℃ at 10℃ / min, followed by heating from 900℃ to 1300~1400℃ at 3℃ / min, and held at that temperature for 5~8h. Then, the material is cooled to room temperature with the furnace to obtain the final product.

Images