A high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass, its preparation method and applications

Abstract

This invention belongs to the field of mid-infrared optical device materials technology, specifically disclosing a high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass, its preparation method, and its applications. The lanthanum aluminate glass comprises the following components by molar percentage: 42-72 mol% alumina, 20-58 mol% lanthanum oxide, and 1-22 mol% hafnium dioxide; all oxides are analytically pure raw materials with a purity greater than 99.95%. This invention utilizes the aforementioned high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass, its preparation method, and its applications to prepare a novel hafnium-doped lanthanum-aluminum high-refractive-index optical glass. This glass has a refractive index above 2.0, along with a high glass transition temperature and Vickers hardness, meeting the requirements of electronic display lenses and windows, and thus can be applied to next-generation ultra-thin AR / VR technology and electronic imaging.

Description

Technical Field

[0001] This invention belongs to the field of mid-infrared optical device materials technology, specifically relating to a high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass, its preparation method, and its applications. Background Technology

[0002] To reduce the size of optical systems such as digital cameras, endoscopes, and microscopes, and to minimize chromatic aberration, there is a significant demand for optical glasses that combine high refractive index, low wavelength dispersion, and high transparency across a wide wavelength range. High-refractive-index glass, as a core component of electronic display technology, plays an indispensable role in display systems for augmented reality (AR) and mixed reality (MR) devices, smartphones, and military electronic reconnaissance display equipment. With the rapid development of electronic display technology, high-refractive-index glass (2.0 and above) provides crucial support for building high-brightness and clarity systems in high-quality display systems due to its effective light refraction properties. With the continuous advancement of AR / VR technology, the demand for high-refractive-index glass is experiencing explosive growth. In the smartphone field, high-refractive-index glass, with its excellent optical and mechanical properties, provides smartphones with clear display effects. Therefore, finding materials with even higher refractive indices is of great significance for promoting the development of AR technology.

[0003] Currently, glasses with a refractive index higher than 2.0 generally contain a large amount of heavy metal oxides, such as PbO, Bi2O3, and TeO2. These elements often cause high-wavelength refraction and dispersion, resulting in dark colors in the visible range, thus limiting their applications. Secondly, glass materials generally suffer from low hardness and poor toughness, significantly limiting their use as electron optical window materials that directly contact relatively harsh external environments. Recent domestic and international research shows that aluminate glass materials can significantly improve the hardness, mechanical properties, and glass transition temperature of glass materials.

[0004] Currently, reports on high-refractive-index glasses both domestically and internationally mainly include lead glass, tellurate glass, bismuthate glass, and lanthanum boron, along with their preparation methods. These materials mainly contain toxic elements and involve issues such as volatility. In addition, due to limitations in composition and preparation technology, these glasses have low hardness and toughness, poor chemical stability, and poor uniformity in composition and melting, which limits their use as electronic display materials.

[0005] Therefore, there is a need in this field to develop a high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass, its preparation method, and its applications. By introducing hafnium, optical glass with high hardness, high toughness, low phonon energy, high refractive index, and good thermal stability can be obtained, which can effectively solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass, its preparation method, and its application. A novel hafnium-doped lanthanum aluminum-based high-refractive-index optical glass is prepared, which has a refractive index of 2.0 or higher, and also has a high glass transition temperature and Vickers hardness, to meet the requirements of electronic display lenses and windows, and thus can be applied to next-generation ultra-thin AR / VR technology and electronic imaging.

[0007] To achieve the above objectives, the present invention provides a high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass, comprising the following components by molar percentage: 42-72 mol% alumina, 20-58 mol% lanthanum oxide, and 1-22 mol% hafnium dioxide; all oxides are analytical grade raw materials with a purity greater than 99.95%.

[0008] Preferably, the high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass has a Vickers hardness of 9.1-11.2 GPa, an indentation fracture resistance of 30-45 N, a visible light transmittance of >85%, a refractive index n>2.02, and a transition temperature of >850℃.

[0009] A method for preparing high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass includes the following steps:

[0010] Step S1: Prepare a uniformly mixed powder mixture;

[0011] Step S2: Place the powdered compound into a porous mold, filling each mold with 20-25 mg of powdered compound, set the pressure to 20-25 MPa, and press the powdered compound into a sheet-like block.

[0012] Step S3: Place the sheet-like block into a containerless pneumatic suspension furnace, turn on the upper carbon dioxide laser, adjust the power to 50-60W, and the melting temperature to 2200-2500℃ to melt the sheet-like block into irregular ceramic sphere samples; turn on the suspension gas and simultaneously turn on the lower carbon dioxide laser, adjusting the power to 40-50W.

[0013] Step S4: Simultaneously adjust the power of the upper and lower carbon dioxide lasers, turn on the airflow control system to make the sample resonate, and make the sample temperature reach 2200-2500℃. Stabilize the airflow and laser system for 2 minutes to ensure that the entire sample melts evenly.

[0014] Step S5: Quickly turn off the carbon dioxide laser at the resonant frequency, and the sample is rapidly cooled to obtain a high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass sample;

[0015] Step S6: Place the high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass sample into an annealing furnace for annealing treatment. The annealing temperature is 840℃ and the annealing time is 2 hours. Cool the sample in the furnace to obtain high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass.

[0016] Preferably, step S1 specifically involves:

[0017] Step S11: Alumina, lanthanum oxide, and hafnium dioxide are subjected to high-temperature calcination at 700°C for 2 hours to reduce the moisture and hydroxyl content of the glass raw materials;

[0018] Step S12: Weigh the powder according to the molar percentage composition of alumina 42-72 mol%, lanthanum oxide 20-58 mol%, and hafnium dioxide 1-22 mol%, and ball mill to obtain the original powder;

[0019] Step S13: Add an appropriate amount of alcohol dispersion medium to the original powder to obtain mixture A; then place mixture A on a magnetic stirrer and stir thoroughly for 1-2 hours to obtain a uniformly mixed mixture B.

[0020] Step S14: Dry the mixture B at 500℃ for the second time to obtain dried mixture B;

[0021] Step S15: Add polyvinyl alcohol to the dried mixture B and magnetically stir for 2-3 hours to obtain mixture C; after stirring, sinter mixture C at 1200℃ to remove polyvinyl alcohol from mixture C and obtain a uniformly mixed powder.

[0022] Preferably, the heating rate of high-temperature calcination in step S11 and sintering in step S15 is 5-10℃ / min.

[0023] Preferably, in step S2, the pressing time is 5 to 10 minutes.

[0024] Preferably, in step S3, the gas used in the pneumatic suspension furnace is air; ensuring that the upper laser power / lower laser power is 1.2 to 1.5.

[0025] Preferably, in step S5, the cooling rate is 500-1000°C / s.

[0026] A method for preparing high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass; application of the prepared high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass in imaging systems and electronic components.

[0027] The present invention employs the above-mentioned high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass, its preparation method, and its application, with the following beneficial effects:

[0028] (1) The high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass obtained by the present invention has excellent transmittance in the visible light region and near-mid-infrared band. After grinding and polishing, it can be made into an electronic optical device with excellent mechanical properties and good transmittance.

[0029] (2) The high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass prepared by this invention has good mechanical properties. Experiments have shown that the introduction of hafnium oxide can significantly improve the hardness of the glass and it has excellent anti-crystallization properties, thermal shock resistance and corrosion resistance.

[0030] (3) The high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass prepared by this invention does not involve toxic components such as fluorine, chlorine, sulfur, and lead during the preparation process, and has good environmental protection and safety.

[0031] (4) The high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass (10mm thick) prepared by the present invention has the following characteristics: transmittance in the visible light region (800-2800nm) ≥80%; refractive index ≥2.2; hardness ≥9.1MPa; softening temperature ≥850℃; water resistance stability is grade III; and toughness ≥30N.

[0032] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0033] Figure 1 This is the resonance displacement curve of lanthanum aluminate melt in Example 1 of the present invention, which describes a high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass, its preparation method, and its application.

[0034] Figure 2 The cooling curves of the glass and the standard sample alumina are shown in Example 1 of the present invention, which describes a high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass, its preparation method, and its application.

[0035] Figure 3 The X-ray diffraction pattern of the glass in the first application example of the present invention is shown below;

[0036] Figure 4 This is a DSC curve of the glass in Example 1 of the present invention, which describes a high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass, its preparation method, and its application.

[0037] Figure 5 This is a refractive index curve of a high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass, its preparation method, and its application example 1 of the present invention.

[0038] Figure 6 This is a micro-indentation image of a high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass, its preparation method, and its application example 1, taken at 50 N.

[0039] Figure 7 This is the transmission spectrum of the glass in Example 1 of the present invention, which describes a high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass, its preparation method, and its application. Detailed Implementation

[0040] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0041] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0042] Example 1

[0043] A high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass includes the following steps:

[0044] Step S1: Prepare a uniformly mixed powder batch by one mechanical mixing and two solvent mixing.

[0045] Step S11: Alumina, lanthanum oxide, and hafnium dioxide are subjected to high-temperature calcination at 700°C for 2 hours to reduce the moisture and hydroxyl content of the glass raw materials.

[0046] Step S12: Weigh 12 mol% hafnium dioxide (HfO2), 30 mol% lanthanum oxide (La2O3), and 58 mol% aluminum oxide (Al2O3) as high-purity compounding materials according to the molar percentage composition ratio, and ball mill them to obtain the original powder.

[0047] Step S13: Place the original compounded powder into an alumina crucible, add an appropriate amount of alcohol dispersion medium to the original powder to obtain mixture A. Then place mixture A on a magnetic stirrer and stir thoroughly for 2 hours to obtain a homogeneous mixture B.

[0048] Step S14: Place the mixture B in a glass furnace at 500℃ and heat for 2 hours for secondary drying to obtain dried mixture B.

[0049] Step S15: Add polyvinyl alcohol to the dried mixture B and magnetically stir for 2 hours to obtain mixture C. After stirring, sinter mixture C at 1200℃ for 2 hours to remove impurities and organic solvents, resulting in a uniformly mixed powder.

[0050] Step S2: Place the powdered compound into a stainless steel porous mold, filling each mold with 25mg of powdered compound, and set the pressure to 20MPa to press the powdered compound into sheet-like blocks.

[0051] Step S3: Place the sheet-like block into a containerless pneumatic levitation furnace. Turn on the upper carbon dioxide laser, adjust the power to 50W, and the melting temperature to 2500℃ to melt the sheet-like block into irregular ceramic sphere samples. Turn on the levitation gas and simultaneously turn on the lower carbon dioxide laser, adjusting the power to 40W.

[0052] Step S4: Simultaneously adjust the power of the upper and lower carbon dioxide lasers, turn on the airflow control system to make the sample resonate, and make the sample temperature reach 2200℃. Stabilize the airflow and laser system for 2 minutes to ensure that the entire sample melts evenly.

[0053] Step S5, as follows Figure 1 As shown, the carbon dioxide laser is rapidly shut down at the resonant frequency, as... Figure 2 As shown, the sample was rapidly cooled at 500-1000℃ / s to obtain a high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass sample with a diameter of 3 mm.

[0054] Step S6: Place the high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass sample into an annealing furnace for annealing treatment. The annealing temperature is 840℃ and the annealing time is 2 hours. Cool the sample with the furnace to obtain the high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass.

[0055] The high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass prepared in this embodiment was first subjected to XRD testing, such as... Figure 3 As shown, the sample showed no crystallization peaks, confirming that it was a glass sample. Next, the high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass was subjected to DSC thermal analysis. The DSC curve of the glass is shown below. Figure 4 As shown, the transition temperature (Tg) of the high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass is 861℃, and the crystallization initiation temperature (Tx) is 993℃. Its Vickers hardness is 9.57 GPa, and its shatter resistance is 35 N. Figure 5 As shown, the refractive index of the high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass is 2.02. The visible light transmittance of the high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass is greater than 80%.

[0056] Example 2

[0057] Step S1: Prepare a uniformly mixed powder batch.

[0058] Step S11: Alumina, lanthanum oxide, and hafnium dioxide are subjected to high-temperature calcination at 700°C for 2 hours to reduce the moisture and hydroxyl content of the glass raw materials.

[0059] Step S12: Weigh 22 mol% hafnium dioxide (HfO2), 20 mol% lanthanum oxide (La2O3), and 58 mol% aluminum oxide (Al2O3) as high-purity compounding materials according to the molar percentage composition ratio, and ball mill them to obtain the original powder.

[0060] Step S13: Place the original compounded powder into an alumina crucible, add an appropriate amount of alcohol dispersion medium to the original powder to obtain mixture A. Then place mixture A on a magnetic stirrer and stir thoroughly for 2 hours to obtain a homogeneous mixture B.

[0061] Step S14: Place the mixture B in a glass furnace at 500℃ and heat for 2 hours for secondary drying to obtain dried mixture B.

[0062] Step S15: Add polyvinyl alcohol to the dried mixture B and magnetically stir for 2 hours to obtain mixture C. After stirring, sinter mixture C at 1200℃ for 2 hours to remove impurities and organic solvents, resulting in a uniformly mixed powder.

[0063] Step S2: Place the powdered compound into a stainless steel porous mold, filling each mold with 20mg of powdered compound, and set the pressure to 20MPa to press the powdered compound into sheet-like blocks.

[0064] Step S3: Place the sheet-like block into a containerless pneumatic levitation furnace. Turn on the upper carbon dioxide laser, adjust the power to 60W, and the melting temperature to 2500℃ to melt the sheet-like block into irregular ceramic sphere samples. Turn on the levitation gas and simultaneously turn on the lower carbon dioxide laser, adjusting the power to 50W.

[0065] Step S4: Simultaneously adjust the power of the upper and lower carbon dioxide lasers, turn on the airflow control system to make the sample resonate, make the sample temperature reach 2500℃, stabilize the airflow and laser system for 2 minutes, and ensure that the entire sample melts evenly.

[0066] Step S5: Quickly turn off the carbon dioxide laser at the resonant frequency and rapidly cool the sample at 500-1000℃ / s to obtain a high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass sample with a diameter of 3mm.

[0067] Step S6: Place the high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass sample into an annealing furnace for annealing treatment. The annealing temperature is 845℃ and the annealing time is 2 hours. Cool the sample in the furnace to obtain the high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass.

[0068] The high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass prepared in this embodiment was first subjected to XRD testing. The absence of crystallization peaks confirmed that the sample was indeed a glass. Next, the high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass was subjected to DSC thermal analysis. The lanthanum aluminate glass exhibited a transition temperature (Tg) of 869℃, a crystallization initiation temperature (Tx) of 1003℃, a Vickers hardness of 9.97 GPa, a shatter resistance of 39 N, and a refractive index of 2.12. Figure 6 As shown. The high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass prepared in this embodiment has a visible light transmittance greater than 80%, as shown. Figure 7 As shown.

[0069] Therefore, this invention utilizes the aforementioned high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass, its preparation method, and its application to prepare a novel hafnium-doped lanthanum aluminum-based high-refractive-index optical glass. This glass has a refractive index of over 2.0, as well as a high glass transition temperature and Vickers hardness, to meet the requirements of electronic display lenses and windows, thus enabling its application in next-generation ultra-thin AR / VR technology and electronic imaging.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass, characterized in that, The product comprises the following components by molar percentage: 42-72 mol% aluminum oxide, 20-58 mol% lanthanum oxide, and 1-22 mol% hafnium dioxide; all oxides are analytical grade raw materials with a purity greater than 99.95%. The Vickers hardness of high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass is 9.1-11.2 GPa, its indentation fracture resistance is 30-45 N, its visible light transmittance is >85%, its refractive index n is >2.02, and its transition temperature is >850℃.

2. A method for producing high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass as described in claim 1, characterized in that, Includes the following steps: Step S1: Prepare a uniformly mixed powder mixture; Step S2: Place the powdered compound into a porous mold, filling each mold with 20-25 mg of powdered compound, set the pressure to 20-25 MPa, and press the powdered compound into a sheet-like block. Step S3: Place the sheet-like block into a containerless pneumatic suspension furnace, turn on the upper carbon dioxide laser, adjust the power to 50-60W, and the melting temperature to 2200-2500℃ to melt the sheet-like block into irregular ceramic sphere samples; turn on the suspension gas and simultaneously turn on the lower carbon dioxide laser, adjusting the power to 40-50W. The gas used in the pneumatic suspension furnace is air; ensure that the upper laser power / lower laser power ratio is 1.2 to 1.

5. Step S4: Simultaneously adjust the power of the upper and lower carbon dioxide lasers, turn on the airflow control system to make the sample resonate, and make the sample temperature reach 2200-2500℃. Stabilize the airflow and laser system for 2 minutes to ensure that the entire sample melts evenly. Step S5: Quickly turn off the carbon dioxide laser at the resonant frequency, and the sample is rapidly cooled to obtain a high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass sample; The cooling rate is 500–1000 °C / s; Step S6: Place the high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass sample into an annealing furnace for annealing treatment. The annealing temperature is 840℃ and the annealing time is 2 hours. Cool the sample in the furnace to obtain high-hardness, high-toughness, and high-refractive-index lanthanum aluminate glass.

3. The method for preparing a high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass according to claim 2, characterized in that: Step S1 specifically involves: Step S11: Alumina, lanthanum oxide, and hafnium dioxide are subjected to high-temperature calcination at 700°C for 2 hours to reduce the moisture and hydroxyl content of the glass raw materials; Step S12: Weigh the powder according to the molar percentage composition of alumina 42-72 mol%, lanthanum oxide 20-58 mol%, and hafnium dioxide 1-22 mol%, and ball mill to obtain the original powder; Step S13: Add an appropriate amount of alcohol dispersion medium to the original powder to obtain mixture A; then place mixture A on a magnetic stirrer and stir thoroughly for 1-2 hours to obtain a uniformly mixed mixture B. Step S14: Dry the mixture B at 500℃ for the second time to obtain dried mixture B; Step S15: Add polyvinyl alcohol to the dried mixture B and magnetically stir for 2-3 hours to obtain mixture C; after stirring, sinter mixture C at 1200℃ to remove polyvinyl alcohol from mixture C and obtain a uniformly mixed powder.

4. The method for preparing a high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass according to claim 3, characterized in that: The heating rate for high-temperature calcination in step S11 and sintering in step S15 is 5-10℃ / min.

5. The method for preparing a high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass according to claim 2, characterized in that: In step S2, the compression time is 5 to 10 minutes.

6. The application of high-hardness, high-toughness, high-refractive-index lanthanum aluminate glass prepared by the method described in any one of claims 2-5 in imaging systems and electronic components.

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