Germanate transparent glass-ceramics, methods of making and using the same

Abstract

This invention discloses a germanate transparent glass-ceramic, wherein the main crystalline phase of the germanate transparent glass-ceramic is a rare-earth-containing fluoride, which is uniformly distributed in the residual glass phase. The preparation method of the germanate transparent glass-ceramic includes: uniformly mixing the components of the germanate transparent glass-ceramic to obtain a mixture; melting the mixture at 1300-1550℃ and holding it at that temperature for 10-150 min to obtain a glass melt; rapidly cooling the glass melt to form a solid shape, and then annealing it at 200-450℃ for 2-24 h to obtain a glass precursor; holding the glass precursor at 450-650℃ for 4-60 h and then naturally cooling it to obtain the germanate transparent glass-ceramic. This invention also discloses the applications of the germanate transparent glass-ceramic. The germanate transparent glass-ceramic provided by this invention has the advantages of a wide transmission range, low phonon energy, high refractive index, high hardness, high transparency, and suitability for rare-earth upconversion luminescence.

Description

Technical Field

[0001] This invention relates to the field of ceramic glass technology, specifically to a germanate transparent glass ceramic, its preparation method, and its application. Background Technology

[0002] Germanate glass has advantages such as low phonon energy, high solubility for rare earth ions, wide infrared light transmission range, high thermal and chemical stability, and high refractive index. It is a key and hot material for research in rare earth doped luminescence, infrared optical windows, nonlinear optics and other fields.

[0003] However, germanate glass has a higher phonon energy than fluoride crystals, while its crystal field is weaker, resulting in weaker rare-earth luminescence in germanate glass compared to fluoride crystals. Secondly, the excitation source easily penetrates transparent materials, leading to lower utilization of the excitation source in germanate glass. Furthermore, considering the high similarity in charge and ion size between trivalent rare-earth ions, rare-earth-containing fluoride crystals would be more suitable for rare-earth luminescent center doping. However, rare-earth-containing fluoride crystals are not easily precipitated in germanate glass.

[0004] Therefore, developing a germanate transparent glass-ceramic material that can simultaneously possess the advantages of germanate glass and fluoride crystals, and utilizing the precipitated rare-earth-containing fluoride nanocrystals to enhance the upconversion luminescence intensity while retaining the advantages of germanate glass, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] To address the aforementioned shortcomings of existing technologies, the present invention aims to provide a germanate transparent glass-ceramic, its preparation method, and its applications. The germanate transparent glass-ceramic provided by the present invention exhibits a large amount of rare-earth-containing fluorides precipitated internally, resulting in enhanced upconversion luminescence intensity.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A germanate transparent glass-ceramic, wherein the main crystalline phase of the germanate transparent glass-ceramic is a rare earth-containing fluoride, and the main crystalline phase is uniformly distributed in the residual glass phase.

[0008] Preferably, the germanate transparent glass ceramic has a transmittance of over 80% in the visible and infrared light ranges; and under excitation by a 980nm light source, the luminescence intensity of the transparent glass ceramic is enhanced compared to the glass precursor.

[0009] Preferably, the product comprises the following components in molar amounts:

[0010] Ge-containing compounds: 20-61 parts;

[0011] Ceramic powder: 3-40 parts;

[0012] Alkali metal compounds: 13-45 parts;

[0013] Rare earth compounds: 7-25 parts.

[0014] Preferably, the Ge-containing compound is GeO2 and / or Na2Ge4O9.

[0015] Preferably, the ceramic powder is one or more of Al2O3, AlF3, Al(NO3)3, and Al(NO3)3·9H2O.

[0016] Preferably, the alkali metal compound is one or more of NaF, Na2CO3 and NaHCO3.

[0017] Preferably, the rare earth compound is one or more of YF3, YbF3, TmF3, ErF3, Y2O3, Yb2O3, Tm2O3 and Er2O3.

[0018] This invention also provides a method for preparing germanate transparent glass ceramics, comprising the following steps:

[0019] The components of germanate transparent glass ceramic are mixed evenly to obtain a mixture.

[0020] The mixture is melted at 1300-1550℃ and held for 10-150 minutes to obtain a glass melt;

[0021] After the glass melt is rapidly cooled and shaped, it is annealed at 200-450℃ for 2-24 hours to obtain the glass precursor.

[0022] The germanate transparent glass ceramic is prepared by holding the glass precursor at 450-650℃ for 4-60 hours and then naturally cooling it.

[0023] Preferably, the components of the germanate transparent glass-ceramic, in molar fractions, include:

[0024] Ge-containing compounds: 20-61 parts;

[0025] Ceramic powder: 3-40 parts;

[0026] Alkali metal compounds: 13-45 parts;

[0027] Rare earth compounds: 7-25 parts.

[0028] Preferably, the rapid cooling forming involves casting the molten glass into a mold or pouring the molten glass into a cooling liquid.

[0029] This invention also discloses an application of germanate transparent glass ceramic, which is used in display device cover plates, light-emitting devices, nonlinear optics, and temperature sensing fields.

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

[0031] 1. The germanate transparent glass ceramic provided by this invention contains a large number of fluoride nanocrystals by adding rare earth compounds to the ceramic formulation. Because the fluoride nanocrystals have low phonon energy and the similar charges and radii of rare earth ions facilitate substitution, the upconversion luminescence intensity of the germanate transparent glass ceramic is significantly enhanced. The germanate transparent glass ceramic prepared by this invention achieves a transmittance of over 80% in the visible and infrared light ranges, exhibiting a wide transmittance range. Under 980nm light source excitation, the luminescence is significantly enhanced compared to the glass precursor. Simultaneously, because the rare earth-containing fluoride nanocrystals are uniformly distributed in the residual glass, they hinder crack propagation during material failure, which is highly beneficial for improving the mechanical properties of the material, manifested in the high micro-Vickers hardness of the germanate transparent glass ceramic. Furthermore, the germanate glass system inherently possesses low phonon energy and high refractive index; therefore, this germanate transparent glass ceramic also has the advantages of low phonon energy, high refractive index, and high transparency.

[0032] 2. The method for preparing germanate transparent glass ceramics provided by this invention involves preparing a precursor glass via melt quenching, followed by direct heat treatment of the glass precursor to precipitate a large amount of rare-earth-containing fluoride nanocrystals within the glass, thus obtaining germanate transparent glass ceramics. Specifically, during the holding period at 450–650℃ for 4–60 hours, a large amount of rare-earth-containing fluoride nanocrystals precipitate within the germanate transparent glass ceramic, thereby preparing germanate transparent glass ceramics with high transparency and a wide infrared transmission range. This preparation method is simple in steps, has a short preparation cycle, and has the advantages of increasing production capacity and reducing costs.

[0033] 3. The germanate transparent glass ceramic provided by this invention has good application prospects in the fields of optical windows in the ultraviolet-visible-infrared range, rare earth luminescent substrates, display device cover plates, light-emitting devices, optical temperature sensing and nonlinear optics. Attached Figure Description

[0034] Figure 1 This is a flowchart illustrating the preparation process of germanate transparent glass ceramics in this embodiment of the invention.

[0035] Figure 2 The XRD diffraction pattern is shown for the transparent glass-ceramic prepared in Example 1 of this invention.

[0036] Figure 3This is a scanning electron microscope image of the transparent glass-ceramic prepared in Example 1 of the present invention.

[0037] Figure 4 This is the transmission spectrum of the transparent glass-ceramic prepared in Example 1 of the present invention.

[0038] Figure 5 The upconversion emission spectra of the glass precursor and transparent glass ceramic prepared in Example 1 of this invention are shown.

[0039] Figure 6 The results are the micro Vickers hardness test results of the transparent glass ceramic prepared in Example 1 of this invention.

[0040] Figure 7 The XRD diffraction pattern is shown for the transparent glass-ceramic prepared in Example 2 of this invention.

[0041] Figure 8 The upconversion emission spectra of the glass precursor and transparent glass ceramic prepared in Example 2 of this invention are shown.

[0042] Figure 9 The XRD diffraction pattern is shown for the transparent glass-ceramic prepared in Example 3 of this invention.

[0043] Figure 10 The upconversion emission spectra of the glass precursor and transparent glass ceramic prepared in Example 3 of this invention are shown.

[0044] Figure 11 The XRD diffraction pattern is shown for the transparent glass-ceramic prepared in Example 4 of this invention.

[0045] Figure 12 The upconversion emission spectra of the glass precursor and transparent glass ceramic prepared in Example 4 of this invention are shown. Detailed Implementation

[0046] This invention discloses a germanate transparent glass-ceramic, wherein the main crystalline phase of the germanate transparent glass-ceramic is a rare-earth-containing fluoride, and the main crystalline phase is uniformly distributed in the residual glass phase. The germanate transparent glass-ceramic comprises the following components in molar parts:

[0047] Ge-containing compounds: 20-61 parts;

[0048] Ceramic powder: 3-40 parts;

[0049] Alkali metal compounds: 13-45 parts;

[0050] Rare earth compounds: 7-25 parts.

[0051] Germanate transparent glass ceramics contain a large number of fluoride nanocrystals, thus exhibiting high micro-Vickers hardness and transmittance exceeding 80% in the visible and infrared light ranges. Under 980nm excitation, their luminescence is significantly enhanced compared to glass precursors. They possess advantages such as a wide transmittance range, low phonon energy, high refractive index, high hardness, and high transparency.

[0052] This invention also discloses a germanate transparent glass-ceramic, wherein the main crystalline phase of the germanate transparent glass-ceramic is a rare earth-containing fluoride, and the main crystalline phase is uniformly distributed in the residual glass phase.

[0053] The preparation method of this germanate transparent glass ceramic includes the following steps:

[0054] The components of germanate transparent glass ceramic are mixed evenly to obtain a mixture.

[0055] The mixture is melted at 1300-1550℃ and held for 10-150 minutes to obtain a glass melt;

[0056] After the glass melt is rapidly cooled and shaped, it is annealed at 200-450℃ for 2-24 hours to obtain the glass precursor.

[0057] The germanate transparent glass ceramic is prepared by holding the glass precursor at 450-650℃ for 4-60 hours and then naturally cooling it.

[0058] This preparation method is simple in steps and has a short preparation cycle, and has the advantages of increasing production capacity and reducing costs.

[0059] Example 1

[0060] A germanate transparent glass-ceramic, comprising, by molar parts: 43.87 parts GeO2, 14 parts Al2O3, 30 parts NaF, 10 parts YF3, 2 parts YbF3, 0.03 parts TmF3, and 0.1 parts ErF3.

[0061] See Figure 1 The preparation method of this germanate transparent glass ceramic is as follows:

[0062] After weighing the above components, grind them manually in an agate mortar for 30 minutes to obtain a mixture.

[0063] The mixture is loaded into a covered corundum crucible and slightly compacted. The corundum crucible containing the material is then transferred to an electric furnace and heated from room temperature to 1450°C at a heating rate of 10°C / min and held for 60 minutes to obtain glass melt.

[0064] The molten glass is poured into a brass mold preheated to 400°C. The glass is then transferred along with the mold to an electric furnace preheated to 400°C and held at that temperature for 8 hours. After holding, the glass is cooled to room temperature in the furnace to obtain the glass precursor.

[0065] The glass precursor is cut, and the cut glass is placed in an electric furnace and heated from room temperature to 610°C at a heating rate of 5°C / min and held at that temperature for 8 hours. After the holding time is completed, the glass is cooled with the furnace to obtain transparent glass ceramic.

[0066] The transparent glass-ceramics prepared in this embodiment were characterized by XRD, scanning electron microscopy, transmission spectroscopy, upconversion luminescence, and micro-Vickers hardness.

[0067] The XRD diffraction pattern of the transparent glass-ceramic prepared in this embodiment is as follows: Figure 2 As shown. From Figure 2 It can be seen that the four main diffraction peaks of the transparent glass-ceramic are located at 27.9°, 32.6°, 46.5°, and 55.1°. Comparison with the standard card shows that the main crystalline phase of the prepared glass-ceramic is NaY3F. 10 .

[0068] Figure 3 This is a scanning electron microscope image of the transparent glass-ceramic prepared in this embodiment. As can be seen from the image, the main crystalline phase of the transparent glass-ceramic is NaY3F. 10 The particles, with a size of 10-50 nm, are spherical and uniformly distributed in the residual glass phase. All Y elements in the glass are crystallized into NaY3F. 10 Therefore, it is estimated that the main crystal phase accounts for approximately 16.0% of the total mass.

[0069] Figure 4 The figure shows the transmission spectrum of the transparent glass-ceramic prepared in this embodiment. As can be seen from the figure, the transparent glass-ceramic achieves a transmittance of 82% in the visible light range and 83% in the infrared range. Furthermore, the transparent glass-ceramic also exhibits certain transmittance in the high-frequency short-wave, mid-frequency medium-wave, and low-frequency short-wave ultraviolet ranges. Therefore, the transparent glass-ceramic prepared in this embodiment has a wide transmittance range.

[0070] Figure 5 The figures show the upconversion emission spectra of the glass precursor and the transparent glass-ceramic prepared in this embodiment. As can be seen from the figures, under 980nm light source excitation, the transparent glass-ceramic exhibits a 3-fold increase in luminescence compared to the glass precursor.

[0071] Figure 6 The micro Vickers hardness test result of the transparent glass-ceramic prepared in this embodiment is 6.79 GPa.

[0072] Example 2

[0073] A germanate transparent glass-ceramic, comprising, by molar parts: 44.4 parts GeO2, 3 parts Al2O3, 22 parts NaF, 20 parts Na2CO3, 10 parts YF3, 0.5 parts YbF3, and 0.1 parts Tm2O3.

[0074] See Figure 1 The preparation method of this germanate transparent glass ceramic is as follows:

[0075] After weighing the above components, grind them manually in an agate mortar for 30 minutes to obtain a mixture.

[0076] The mixture is loaded into a covered corundum crucible and slightly compacted. The corundum crucible containing the material is then transferred to an electric furnace and heated from room temperature to 1300°C at a heating rate of 10°C / min and held for 150 minutes to obtain glass melt.

[0077] The molten glass is poured into a brass mold preheated to 400°C. The glass is then transferred along with the mold to an electric furnace preheated to 400°C and held at that temperature for 8 hours. After holding, the glass is cooled to room temperature in the furnace to obtain the glass precursor.

[0078] The glass precursor is cut, and the cut glass is placed in an electric furnace and heated from room temperature to 450°C at a heating rate of 5°C / minute and held at that temperature for 18 hours. After the holding time is completed, the glass is cooled with the furnace to obtain transparent glass ceramic.

[0079] The transparent glass-ceramic prepared in this embodiment was characterized by XRD, and the upconversion luminescence of the glass precursor and the transparent glass-ceramic was characterized.

[0080] The XRD diffraction pattern of the transparent glass-ceramic prepared in this embodiment is as follows: Figure 7 As shown. From Figure 7 It can be seen that the four main diffraction peaks of the transparent glass ceramic are located at 28.3°, 32.7°, 46.9° and 55.6°. By comparing with the standard card, it can be seen that the main crystalline phase of the prepared glass ceramic is NaYF4.

[0081] The upconversion spectra of the glass precursor and transparent glass-ceramic prepared in this embodiment are as follows: Figure 8 As shown in the figure, under 980nm light source excitation, the luminescence of transparent glass-ceramic is significantly enhanced compared to that of glass precursors.

[0082] Example 3

[0083] A germanate transparent glass-ceramic, comprising, by molar parts: 58.8 parts GeO2, 10 parts Al2O3, 20 parts NaF, 8 parts YF3, 2 parts YbF3, 0.1 parts TmF3, and 0.1 parts ErF3.

[0084] See Figure 1 The preparation method of this germanate transparent glass ceramic is as follows:

[0085] After weighing the above components, grind them manually in an agate mortar for 30 minutes to obtain a mixture.

[0086] The mixture is loaded into a covered corundum crucible and slightly compacted. The corundum crucible containing the material is then transferred to an electric furnace and heated from room temperature to 1550°C at a heating rate of 10°C / min and held for 10 minutes to obtain glass melt.

[0087] The molten glass is poured into a brass mold preheated to 200°C. The glass is then transferred along with the mold to an electric furnace preheated to 200°C and held at that temperature for 24 hours. After the holding time is completed, the glass is cooled to room temperature with the furnace to obtain the glass precursor.

[0088] The glass precursor is cut, and the cut glass is placed in an electric furnace and heated from room temperature to 640°C at a heating rate of 5°C / minute and held at that temperature for 10 hours. After the holding time is completed, the glass is cooled with the furnace to obtain transparent glass ceramic.

[0089] The transparent glass-ceramic prepared in this embodiment was characterized by XRD, and the upconversion luminescence of the glass precursor and the transparent glass-ceramic was characterized.

[0090] The XRD diffraction pattern of the transparent glass-ceramic prepared in this embodiment is as follows: Figure 9 As shown. From Figure 9 It can be seen that the four main diffraction peaks of the transparent glass-ceramic are located at 27.9°, 32.6°, 46.5°, and 55.1°. Comparison with the standard card shows that the main crystalline phase of the prepared glass-ceramic is NaY3F. 10 .

[0091] The upconversion spectra of the glass precursor and transparent glass-ceramic prepared in this embodiment are as follows: Figure 10 As shown in the figure, under 980nm light source excitation, the luminescence of transparent glass-ceramic is effectively enhanced compared to that of glass precursors.

[0092] Example 4

[0093] A germanate transparent glass-ceramic, comprising, by molar parts: 23.87 parts Na2Ge4O9, 21 parts Al2O3, 16 parts AlF3, 16 parts NaF, 21 parts YF3, 2 parts Yb2O3, 0.03 parts Tm2O3, and 0.1 parts Er2O3.

[0094] See Figure 1 The preparation method of this germanate transparent glass ceramic is as follows:

[0095] After weighing the above components, grind them manually in an agate mortar for 30 minutes to obtain a mixture.

[0096] The mixture is loaded into a covered corundum crucible and slightly compacted. The corundum crucible containing the material is then transferred to an electric furnace and heated from room temperature to 1400°C at a heating rate of 10°C / min and held for 80 minutes to obtain glass melt.

[0097] The molten glass is poured into a brass mold preheated to 350°C. The glass is then transferred along with the mold to an electric furnace preheated to 350°C and held at that temperature for 12 hours. After the holding time is completed, the glass is cooled to room temperature with the furnace to obtain the glass precursor.

[0098] The glass precursor is cut, and the cut glass is placed in an electric furnace and heated from room temperature to 610°C at a heating rate of 5°C / minute and held at that temperature for 48 hours. After the holding time is completed, the glass is cooled with the furnace to obtain transparent glass ceramic.

[0099] The transparent glass-ceramics prepared in this embodiment were characterized by XRD, and the upconversion luminescence of the glass precursor and the transparent glass-ceramics was characterized.

[0100] The XRD diffraction pattern of the transparent glass-ceramic prepared in this embodiment is as follows: Figure 11 As shown. From Figure 11 It can be seen that the four main diffraction peaks of the transparent glass-ceramic are located at 27.9°, 32.6°, 46.5°, and 55.1°. Comparison with the standard card shows that the main crystalline phase of the prepared glass-ceramic is NaY3F. 10 .

[0101] The upconversion spectra of the glass precursor and transparent glass-ceramic prepared in this embodiment are as follows: Figure 12 As shown in the figure, under 980nm light source excitation, the luminescence of transparent glass-ceramic is effectively enhanced compared to that of glass precursors.

[0102] As can be seen, rare-earth-containing fluoride nanocrystals were also precipitated in the transparent glass-ceramics prepared in Examples 2-4, effectively enhancing upconversion luminescence. Therefore, Examples 2-4 also possess the advantages of wide infrared transmission range, low phonon energy, high refractive index, high hardness, and high transparency.

[0103] The composition, proportions (molar parts) and heat treatment parameters of germanate transparent glass ceramics in Examples 1 to 4 are shown in Table 1.

[0104] Table 1

[0105] Example 1 Example 2 Example 3 Example 4 <![CDATA[GeO2]]> 43.87 44.4 58.8 / <![CDATA[Na2Ge4O9]]> / / / 23.87 Total Ge-containing compounds 43.87 44.4 58.8 23.87 <![CDATA[Al2O3]]> 14 3 10 21 <![CDATA[AlF3]]> / / / 16 Total ceramic powder 14 3 10 37 NaF 30 22 20 16 <![CDATA[Na2CO3]]> / 20 / / Total alkali metal compounds 30 42 20 16 <![CDATA[YF3]]> 10 10 8 21 <![CDATA[YbF3]]> 2 0.5 2 / <![CDATA[Yb2O3]]> / / / 2 <![CDATA[TmF3]]> 0.03 / 0.1 / <![CDATA[ErF3]]> 0.1 / 0.1 / <![CDATA[Er2O3]]> / / / 0.1 <![CDATA[Tm2O3]]> / 0.1 / 0.03 Total rare earth compounds 12.13 10.6 10.2 23.13 Heat treatment temperature / °C 610 450 640 610 Heat treatment time / h 8 18 10 48 ceramic main crystal phase <![CDATA[NaY3F 10 ]]> <![CDATA[NaYF4]]> <![CDATA[NaY3F 10 ]]> <![CDATA[NaY3F 10 ]]>

[0106] As shown in Table 1, the percentage of each element's molar composition in Examples 1 and 4 is basically the same, differing only in the raw materials used. If the elemental composition is consistent, the resulting glass precursor should be identical. Since the crystalline phase of the prepared transparent glass-ceramic was completely precipitated after heat treatment at 610℃ for 8 hours, the subsequent 40 hours did not alter the results; therefore, the products obtained in the two examples were almost identical. The comparison between Examples 1 and 4 shows that even using different raw materials, transparent glass-ceramics containing the same main crystalline phase can be prepared.

[0107] In summary, the germanate transparent glass ceramics provided in the embodiments of the present invention have the advantages of wide infrared transmission range, low phonon energy, high refractive index, high hardness, and high transparency.

[0108] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A germanate transparent glass-ceramic, characterized in that, The main crystalline phase of the germanate transparent glass-ceramic is a rare-earth-containing fluoride, which is uniformly distributed in the residual glass phase; the germanate transparent glass-ceramic comprises the following components in molar amounts: Ge-containing compounds: 20-61 parts; the Ge-containing compounds are GeO2 and / or Na2Ge4O9; Ceramic powder: 3-40 parts, wherein the ceramic powder is Al2O3, AlF3, Al(NO3)3, or Al(NO3)3. One or more of 9H2O; Alkali metal compound: 13-45 parts, wherein the alkali metal compound is one or more of NaF, Na2CO3 and NaHCO3; Rare earth compounds: 7-25 parts, wherein the rare earth compounds are one or more of YF3, YbF3, TmF3, ErF3, Y2O3, Yb2O3, Tm2O3 and Er2O3; The preparation method of the germanate transparent glass ceramic includes the following steps: The components of germanate transparent glass ceramic are mixed evenly to obtain a mixture. The mixture is melted at 1300-1550℃ and held for 10-150 minutes to obtain a glass melt; After the glass melt is rapidly cooled and shaped, it is annealed at 200-450℃ for 2-24 hours to obtain the glass precursor. The germanate transparent glass ceramic is prepared by holding the glass precursor at 450~650℃ for 4~60h and then naturally cooling it.

2. The germanate transparent glass-ceramic according to claim 1, characterized in that, The germanate transparent glass ceramic has a transmittance of over 80% in the visible and infrared light ranges; under excitation by a 980 nm light source, the luminescence intensity of the transparent glass ceramic is enhanced compared to the glass precursor.

3. The germanate transparent glass-ceramic according to claim 1, characterized in that, The rapid cooling process involves casting the molten glass into a mold or pouring the molten glass into a cooling liquid.

4. An application of a germanate transparent glass-ceramic, characterized in that, The germanate transparent glass ceramic of claim 1 is used in display device cover plates, light-emitting devices, nonlinear optics, and temperature sensing fields.

Images