Germanization-free chalcogenide glass with high refractive index and preparation method thereof

Abstract

The invention discloses germanium-free high-refractive-index chalcogenide glass which comprises the following components in percentage by atom: 1-5% of Bi, 5-15% of Sb, 10-20% of Se, 40-60% of Te and 10-20% of As, and the sum of the atomic percentages of the components is 100%. The microscopic network structure is formed by connecting a triangular pyramid structure unit with As, Sb or Bi atoms as the center and a chain structure composed of Se or Te atoms. According to the chalcogenide glass, the material cost is remarkably reduced, meanwhile, excellent infrared optical performance is achieved, and the comprehensive performance of the chalcogenide glass is superior to that of similar commercial products; according to the preparation method, efficient deoxygenation and impurity control of the raw materials can be achieved, impurity separation and directional condensation of raw material steam are achieved under precise temperature control through a double-temperature-zone distillation process, the purity of the raw materials is further improved, high purity and high uniformity of the finally prepared product are guaranteed, and the reliability of the material in infrared optical application is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of infrared glass and its preparation technology, specifically to a germanium-free high-refractive-index chalcogenide glass and its preparation method. Background Technology

[0002] Infrared imaging technology has significant application value in defense fields such as individual soldier night vision, space-based early warning, and precision guidance, as well as in civilian fields such as medical diagnosis, intelligent driving, and industrial inspection. With major breakthroughs in sensitivity, integration, and cost control achieved by third-generation focal plane array detectors, infrared imaging systems are developing towards lightweighting, miniaturization, and high performance, undergoing a technological leap from "seeing" to "seeing clearly." However, the infrared optical system, as the core of the optical path convergence, faces a "lightweight dilemma," making it difficult to meet the demands of high-end applications such as target recognition and tracking. Therefore, there is an urgent need to develop new, lightweight, and high-performance infrared lens materials.

[0003] High-refractive-index materials have a large refractive index, allowing for smaller center and edge thicknesses in lenses made from them at the same optical power. In complex optical systems, high-refractive-index materials offer greater design freedom, typically achieving the same aberration correction effect with fewer lenses, thus significantly reducing the overall length and weight of the system. Furthermore, high-refractive-index materials are often combined with low dispersion properties, becoming an effective means of correcting chromatic and spherical aberrations. By appropriately combining different materials, system aberrations can be better balanced, resulting in clearer images with less distortion.

[0004] Currently, commonly used high-refractive-index infrared lens materials mainly include germanium single crystals and chalcogenide glasses. Although germanium single crystals have a refractive index as high as 4.0, their extremely high temperature coefficient of refractive index easily leads to severe focal length drift with temperature, causing thermal defocusing, which poses a serious challenge to the athermal design of optical systems. In contrast, chalcogenide glasses have a lower temperature coefficient of refractive index, only about one-tenth that of germanium single crystals. Furthermore, chalcogenide glasses possess advantages such as flexible composition design, diverse processing methods, and excellent amorphous compatibility, making them promising candidates for high-refractive-index lens materials that meet the needs of novel, lightweight, and high-performance infrared systems through material composition optimization and post-processing. However, currently, commercially available high-refractive-index chalcogenide glasses (such as germanium single crystals)... 30 As 13 Se 32 Te 25 The refractive index is 2.71@10 μm; Ge 28 Sb 12 Se 60 The refractive index is 2.60@10 μm; Ge 33 As 12 Se 55High-refractive-index chalcogenide glasses (such as those with a refractive index of 2.50@10 μm) generally rely on a high proportion of germanium. This not only directly leads to high material costs, but more seriously, germanium is a strategic resource subject to national export controls, causing long-term uncertainty in the stability of its supply chain and its price, severely restricting the sustainable and large-scale development of this type of glass. Therefore, developing germanium-free high-refractive-index chalcogenide glasses is not only a practical way to reduce costs, but also a strategic necessity to ensure the independent control of my country's infrared optical technology. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a germanium-free high-refractive-index chalcogenide glass and its preparation method, which significantly reduces material costs while achieving excellent infrared optical performance. The glass has a refractive index of 3.18-3.23 at a wavelength of 10 μm, an infrared window transmittance of 54-57%, and a density of 5.25-5.31 g / cm³, exhibiting superior overall performance compared to similar commercial products. The preparation method of this chalcogenide glass enables efficient deoxygenation and impurity control of the raw materials. Through a dual-temperature zone distillation process, impurity separation and directional condensation of raw material vapor are achieved under precise temperature control, further improving the purity of the raw materials and ensuring the high purity and high uniformity of the final product, thus guaranteeing the reliability of the material in infrared optical applications.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a germanium-free high refractive index chalcogenide glass, wherein the atomic percentage composition of the chalcogenide glass is: Bi: 1-5%, Sb: 5-15%, Se: 10-20%, Te: 40-60%, As: 10-20%, and the sum of the atomic percentages of each component is 100%; the micro-network structure of the chalcogenide glass is formed by interconnecting trigonal pyramidal structural units centered on As, Sb or Bi atoms with chain-like structures composed of Se or Te atoms.

[0007] The above-mentioned method for preparing germanium-free high-refractive-index chalcogenide glasses includes the following steps: 1) Raw material preparation and loading: According to the atomic percentage composition, weigh out the elemental forms of bismuth (Bi), antimony (Sb), selenium (Se), tellurium (Te) and arsenic (As) as raw materials, mix them in an inert atmosphere to form a mixture, and then load it together with the deoxidizer into the glass raw material tube of a clean and dry H-type double-tube quartz ampoule. This glass raw material tube is connected to the purified glass tube. 2) Vacuum sealing and distillation purification: A vacuum is drawn into the H-type double-tube quartz ampoule while the glass raw material tube is heated at a low temperature to further remove residual free water within the H-type double-tube quartz ampoule. The vacuum level is maintained at 10... -3When the pressure is below Pa, the H-type double-tube quartz ampoule is fused and sealed. Then, the H-type double-tube quartz ampoule is placed in a dual-temperature zone distillation furnace and kept at a high temperature to allow the oxides in the mixture to fully react with the deoxidizer. Then, the glass raw material tube is placed in the high-temperature zone and the purified glass tube is placed in the low-temperature zone for distillation purification. The purified material condenses inside the purified glass tube. Distillation purification can remove impurities such as oxides and hydroxyl groups from the raw material, thereby reducing the extrinsic absorption of chalcogenide glass in the infrared region. After purification, the purified glass tube is separated and sealed. 3) Melting, quenching and annealing: The purified glass tube is placed in a swing furnace, and the material in the purified glass tube is swung and melted into a molten material. Then, it is quenched by air cooling and then annealed to obtain the germanium-free high refractive index chalcogenide glass.

[0008] Preferably, in step 1), the H-type double-tube quartz ampoule undergoes the following pretreatment before filling: the inner wall of the H-type double-tube quartz ampoule is washed successively with aqua regia and deionized water, and then thoroughly dried. This pretreatment prevents impurities inside the H-type double-tube quartz ampoule from contaminating the raw materials.

[0009] Preferably, in step 1), the oxygen scavenger is metallic magnesium or metallic aluminum, and the amount of oxygen scavenger added is 0.05-0.3% of the total weight of the mixture. Magnesium and aluminum are both reactive metallic elements that can preferentially react with oxides in the raw materials at high temperatures to generate high-boiling-point, high-stability compounds such as magnesium oxide or aluminum oxide, thereby achieving efficient oxygen removal. If the amount of oxygen scavenger added is too small, the oxide impurities in the raw materials will not be fully removed, while if the content is too large, the oxygen scavenger may be mixed into the raw materials, affecting the optical properties of the glass. Therefore, the present invention controls the amount of oxygen scavenger added to be 0.05-0.3% of the total weight of the mixture.

[0010] Preferably, in step 2), during the heat preservation process, the temperature of the glass raw material tube is 600-700 °C, the temperature of the purified glass tube is 750 °C, and the heat preservation time is 8-14 h. This ensures that the oxides in the raw material react fully with the deoxidizer, while reducing the temperature difference between the two tubes and preventing impurities from migrating to the purified glass tube due to airflow disturbance. During the distillation purification process, the temperature of the high-temperature zone is 800-900 °C, the temperature of the low-temperature zone is 200-300 °C, and the distillation purification time is 8-12 h. This creates a significant temperature and pressure difference, allowing the raw material vapor to migrate directionally into the purified glass tube in the low-temperature zone and condense, thereby achieving impurity separation and raw material purification. In the above heat preservation and distillation purification processes, by placing the glass raw material tube and the purified glass tube in the furnace chambers of the dual-temperature zone distillation furnace at different temperatures, temperature gradient control and effective distillation can be achieved, ensuring the raw material purification effect.

[0011] Preferably, in step 2), the heating temperature of the glass raw material tube during the vacuuming process is 80-200 °C.

[0012] Preferably, in step 3), the temperature of the rocking melting is 800-900 °C and the time is 12-24 h, to ensure that the raw materials are fully and evenly mixed in the purified glass tube.

[0013] As a further preferred embodiment, the heating process before the swing furnace melting adopts a segmented heating method: First, the temperature of the swing furnace is raised to 350 °C in 3 hours and held for 1-2 hours; then, the temperature of the swing furnace is raised to 650 °C in 3 hours and held for 1-2 hours; finally, the temperature of the swing furnace is raised to 800-900 °C in 4 hours. This segmented heating method effectively reduces the thermal stress on the H-type double-tube quartz ampoule by gradually mitigating the temperature changes within the furnace, while simultaneously allowing the gradual release of volatile components from the raw materials. This prevents the H-type double-tube quartz ampoule from cracking due to a sudden increase in vapor pressure, thereby ensuring the safety and stability of the melting process.

[0014] As a further preferred option, after the swing melting is completed, the temperature of the swing furnace is first reduced to 650°C over 4 hours, and the glass raw material tube is kept in a vertical position for 2 hours to avoid the phenomenon of glass liquid adhering to the wall, and then air-cooled quenching is performed.

[0015] Preferably, in step 3), the annealing temperature is 140-180 °C and the annealing time is 48-72 h to release the internal stress of the glass.

[0016] Compared with the prior art, the present invention has the following advantages: (1) The chalcogenide glass of the present invention is a germanium-free Bi-Sb-Se-Te-As system chalcogenide glass. The chalcogenide glass has a specific atomic percentage composition and micro-network structure. It does not contain expensive germanium, which significantly reduces the material cost. The preparation cost per kilogram is about RMB 1,300, which is much lower than the high refractive index chalcogenide glass commonly found on the market. It has outstanding cost competitiveness and economic advantages. (2) The chalcogenide glass of the present invention exhibits excellent optical properties in the infrared band, specifically high refractive index and good light transmittance. Its refractive index at a wavelength of 10 μm is 3.18-3.23, its infrared window transmittance is 54-57%, and its density is 5.25-5.31 g / cm³. 3 It also has low absorption and scattering loss, and its overall optical performance is superior to similar commercial products, which can meet the key material requirements of high-performance infrared optical systems. (3) The method for preparing chalcogenide glass of the present invention can achieve efficient deoxygenation and impurity control of raw materials, and through the dual-temperature zone distillation process, impurity separation and directional condensation of raw material vapor can be achieved under precise temperature control, further improving the purity of raw materials, ensuring the high purity and high uniformity of the final product, and ensuring the reliability of the material in infrared optical applications. Attached Figure Description

[0017] Figure 1 Bi3Sb7Se of Example 1 20 Te 60 As 10 Schematic diagram of the microstructure of chalcogenide glasses; Figure 2 Bi3Sb7Se of Example 1 20 Te 60 As 10 Refractive index test results of chalcogenide glasses; Figure 3 Bi3Sb7Se of Example 1 20 Te 60 As 10 Transmittance curves of chalcogenide glasses. Detailed Implementation

[0018] To better understand the present invention, the following detailed description is provided in conjunction with embodiments. However, the implementation of the present invention is not limited thereto. For process parameters not specifically described, conventional techniques can be referred to.

[0019] Example 1: The atomic percentage composition of the germanium-free high-refractive-index chalcogenide glass in this example is expressed by the chemical formula: Bi3Sb7Se 20 Te 60 As 10 Its preparation method includes the following steps: 1) Raw material preparation and loading: According to the atomic percentage composition, weigh out bismuth, antimony, selenium, tellurium and arsenic in elemental form with a purity of 5N as raw materials. Weigh each raw material according to the required weight in a glove box filled with inert gas and mix them evenly to obtain a mixture. Prepare an H-type double-tube quartz ampoule. Wash the inner wall of the H-type double-tube quartz ampoule with aqua regia and deionized water, and then dry it thoroughly. Load 260 g of the mixture and 0.78 g of magnesium strip into the clean and dry glass raw material tube of the H-type double-tube quartz ampoule. The glass raw material tube is connected to the purified glass tube. The inner diameter of both the glass raw material tube and the purified glass tube is 52 mm. 2) Vacuum sealing and distillation purification: A vacuum is drawn into the H-type double-tube quartz ampoule while the glass raw material tube is simultaneously heated at 100 °C until the vacuum level reaches 10... -3When the pressure is below Pa, the H-type double-tube quartz ampoule is sealed using an oxyhydrogen flame. The H-type double-tube quartz ampoule is then placed in a dual-temperature zone distillation furnace and kept at 600 °C and 750 °C for 12 hours. This allows the oxides in the mixture to fully react with the magnesium strip. Then, the glass raw material tube is placed in a high-temperature zone of 900 °C and the purified glass tube in a low-temperature zone of 260 °C for 12 hours of distillation purification, causing the purified materials of Bi, Sb, Se, Te, and As to condense inside the purified glass tube. After purification, the purified glass tube is separated and sealed using an oxyhydrogen flame. 3) Melting, Quenching, and Annealing: The purified glass tube is placed in a swing furnace, and the furnace is heated to 850 °C in stages: First, the temperature of the swing furnace is raised to 350 °C over 3 hours and held for 1 hour; then, the temperature is raised to 650 °C over 3 hours and held for 1 hour; finally, the temperature is raised to 850 °C over 4 hours and held at 850 °C for 18 hours for swing melting to ensure thorough and uniform mixing of the raw materials, allowing the material in the purified glass tube to be swayed and melted into a molten substance. After the swing melting is completed, the temperature of the swing furnace is lowered to 650 °C over 4 hours, and the glass raw material tube is kept vertical for 2 hours. Then, the purified glass tube containing the molten substance is removed from the swing furnace and subjected to air-cooling quenching to solidify the molten substance. After cooling, the purified glass tube is placed in an annealing furnace for annealing at 150 °C for 48 hours. h, to release the internal stress of the glass, after annealing, the germanium-free high refractive index Bi3Sb7Se of Example 1 is obtained. 20 Te 60 As 10 Chalcogenide glass.

[0020] Germanium-free high-refractive-index Bi3Sb7Se of Example 1 20 Te 60 As 10 A schematic diagram of the microstructure of chalcogenide glasses is shown below. Figure 1 As shown, the microstructure of this chalcogenide glass consists of trigonal pyramidal structural units centered on As, Sb, or Bi atoms, interconnected with chain-like structures composed of Se or Te atoms.

[0021] It was estimated that preparing 1 kg of Bi3Sb7Se from Example 1 would yield [a specific product / material]. 20 Te 60 As 10 The cost of chalcogenide glass is approximately 1340 yuan. Example 1: Bi3Sb7Se 20 Te 60 As 10 The refractive index test results of chalcogenide glasses are shown below. Figure 2 The transmittance curve is shown below. Figure 3 Tests showed that the Bi3Sb7Se of Example 1 with a thickness of 2mm... 20 Te 60 As 10 The chalcogenide glass has a refractive index of 3.23 at a wavelength of 10 μm, an infrared window transmittance of 57%, and a density of 5.31 g / cm³. 3 Its performance is superior to that of commercially available high-refractive-index chalcogenide glass.

[0022] Example 2: The atomic percentage composition of the germanium-free high-refractive-index chalcogenide glass in this example is expressed by the chemical formula: Bi5Sb 15 Se 20 Te 40 As 20 Its preparation method includes the following steps: 1) Raw material preparation and loading: Based on atomic percentage composition, weigh out bismuth, antimony, selenium, tellurium and arsenic in elemental form with a purity of 5 N as raw materials. Weigh each raw material according to the required weight in a glove box filled with inert gas and mix them evenly to obtain a mixture. Prepare an H-type double-tube quartz ampoule. Wash the inner wall of the H-type double-tube quartz ampoule with aqua regia and deionized water, and then dry it thoroughly. Load 350 g of the mixture and 0.70 g of magnesium strip into the clean and dry glass raw material tube of the H-type double-tube quartz ampoule. The glass raw material tube is connected to the purified glass tube. The inner diameter of both the glass raw material tube and the purified glass tube is 52 mm. 2) Vacuum sealing and distillation purification: A vacuum is drawn into the H-type double-tube quartz ampoule while the glass raw material tube is simultaneously heated at 90 °C until the vacuum level reaches 10. -3 When the pressure is below Pa, the H-type double-tube quartz ampoule is sealed using an oxyhydrogen flame. The H-type double-tube quartz ampoule is then placed in a dual-temperature zone distillation furnace for heat preservation. During this heat preservation, the temperature of the glass raw material tube is set to 700 °C, and the temperature of the purified glass tube is set to 750 °C for 14 hours. This heat preservation allows the oxides in the mixture to fully react with the magnesium strip. Then, the glass raw material tube is placed in a high-temperature zone of 850 °C, and the purified glass tube is placed in a low-temperature zone of 240 °C for 10 hours of distillation purification, causing the purified materials of Bi, Sb, Se, Te, and As to condense inside the purified glass tube. After purification, the purified glass tube is separated and sealed using an oxyhydrogen flame. 3) Melting, Quenching, and Annealing: The purified glass tube is placed in a swing furnace, and the furnace is heated to 900 °C in stages: First, the temperature of the swing furnace is raised to 350 °C over 3 hours and held for 1 hour; then, the temperature is raised to 650 °C over 3 hours and held for 2 hours; finally, the temperature is raised to 900 °C over 4 hours and held at 900 °C for 20 hours for swing melting to ensure thorough and uniform mixing of the raw materials, allowing the material in the purified glass tube to be swayed and melted into a molten substance. After the swing melting is completed, the temperature of the swing furnace is lowered to 650 °C over 4 hours, and the glass raw material tube is kept vertical for 2 hours. Then, the purified glass tube containing the molten substance is removed from the swing furnace and subjected to air-cooling quenching to solidify the molten substance. After cooling, the purified glass tube is placed in an annealing furnace for annealing at 180 °C for 60 minutes. h, to release the internal stress of the glass, after annealing, the germanium-free high refractive index Bi5Sb of Example 2 is obtained. 15 Se 20 Te 40 As 20 Chalcogenide glass.

[0023] It was estimated that preparing 1 kg of Bi5Sb from Example 2 would yield [a specific yield]. 15 Se 20 Te 40 As 20 The cost of chalcogenide glass is approximately 1300 yuan. Tests showed that the Bi5Sb of Example 2, with a thickness of 2 mm, [was effective]. 15 Se 20 Te 40 As 20 The chalcogenide glass has a refractive index of 3.18 at a wavelength of 10 μm, an infrared window transmittance of 54%, and a density of 5.25 g / cm³. 3 Its performance is superior to that of commercially available high-refractive-index chalcogenide glass.

[0024] Example 3: The atomic percentage composition of the germanium-free high-refractive-index chalcogenide glass in this example is expressed by the chemical formula: Bi 2.5 Sb5Se 20 Te 60 As 12.5 Its preparation method includes the following steps: 1) Raw material preparation and loading: According to the atomic percentage composition, weigh out bismuth, antimony, selenium, tellurium and arsenic in elemental form with a purity of 5 N as raw materials. Weigh each raw material according to the required weight in a glove box filled with inert gas and mix them evenly to obtain a mixture. Prepare an H-type double-tube quartz ampoule. Wash the inner wall of the H-type double-tube quartz ampoule with aqua regia and deionized water, and then dry it thoroughly. Load 400 g of the mixture and 1.20 g of magnesium strip into the clean and dry glass raw material tube of the H-type double-tube quartz ampoule. The glass raw material tube is connected to the purified glass tube. The inner diameter of both the glass raw material tube and the purified glass tube is 52 mm. 2) Vacuum sealing and distillation purification: A vacuum is drawn into the H-type double-tube quartz ampoule while the glass raw material tube is simultaneously heated at 120 °C until the vacuum level reaches 10. -3 When the pressure is below Pa, the H-type double-tube quartz ampoule is sealed using an oxyhydrogen flame. The H-type double-tube quartz ampoule is then placed in a dual-temperature zone distillation furnace for heat preservation. During this heat preservation, the temperature of the glass raw material tube is set to 680 °C, and the temperature of the purified glass tube is set to 750 °C for 13 h. This heat preservation allows the oxides in the mixture to fully react with the magnesium strip. Then, the glass raw material tube is placed in a high-temperature zone of 870 °C, and the purified glass tube is placed in a low-temperature zone of 260 °C for 10 h of distillation purification. This allows the purified materials of Bi, Sb, Se, Te, and As to condense inside the purified glass tube. After purification, the purified glass tube is separated and sealed using an oxyhydrogen flame. 3) Melting, Quenching, and Annealing: The purified glass tube is placed in a swing furnace, and the furnace is heated to 880 °C in stages: First, the temperature of the swing furnace is raised to 350 °C over 3 hours and held for 1.5 hours; then, the temperature is raised to 650 °C over 3 hours and held for 1 hour; finally, the temperature is raised to 880 °C over 4 hours and held at 880 °C for 24 hours for swing melting to ensure thorough and uniform mixing of the raw materials, allowing the material in the purified glass tube to be swayed and melted into a molten substance. After the swing melting is completed, the temperature of the swing furnace is lowered to 650 °C over 4 hours, and the glass raw material tube is kept vertical for 2 hours. Then, the purified glass tube containing the molten substance is removed from the swing furnace and subjected to air-cooling quenching to solidify the molten substance. After cooling, the purified glass tube is placed in an annealing furnace for annealing at 160 °C for 72 hours. h, to release the internal stress of the glass, after annealing, the germanium-free high refractive index Bi of Example 3 is obtained. 2.5 Sb5Se 20 Te 60 As 12.5 Chalcogenide glass.

[0025] It was estimated that preparing 1 kg of Bi in Example 3 would require... 2.5Sb5Se 20 Te 60 As 12.5 The cost of chalcogenide glass is approximately 1320 yuan. Tests showed that the Bi3 glass of Example 3, with a thickness of 2 mm,... 2.5 Sb5Se 20 Te 60 As 12.5 The chalcogenide glass has a refractive index of 3.21 at a wavelength of 10 μm, an infrared window transmittance of 56%, and a density of 5.30 g / cm³. 3 Its performance is superior to that of commercially available high-refractive-index chalcogenide glass.

[0026] Example 4: The atomic percentage composition of the germanium-free high-refractive-index chalcogenide glass in this example is expressed by the chemical formula: Bi4Sb 10 Se 18 Te 50 As 18 Its preparation method includes the following steps: 1) Raw material preparation and loading: According to the atomic percentage composition, weigh out bismuth, antimony, selenium, tellurium and arsenic in elemental form with a purity of 5 N as raw materials. Weigh each raw material according to the required weight in a glove box filled with inert gas and mix them evenly to obtain a mixture. Prepare an H-type double-tube quartz ampoule. Wash the inner wall of the H-type double-tube quartz ampoule with aqua regia and deionized water, and then dry it thoroughly. Load 500 g of the mixture and 1.00 g of magnesium strip into the clean and dry glass raw material tube of the H-type double-tube quartz ampoule. The glass raw material tube is connected to the purified glass tube. The inner diameter of both the glass raw material tube and the purified glass tube is 52 mm. 2) Vacuum sealing and distillation purification: A vacuum is drawn into the H-type double-tube quartz ampoule while the glass raw material tube is simultaneously heated at 130 °C until the vacuum level reaches 10. -3 When the pressure is below Pa, the H-type double-tube quartz ampoule is sealed using an oxyhydrogen flame. The H-type double-tube quartz ampoule is then placed in a dual-temperature zone distillation furnace for heat preservation. During this heat preservation, the temperature of the glass raw material tube is set to 650 °C, and the temperature of the purified glass tube is set to 750 °C for 10 h. This heat preservation allows the oxides in the mixture to fully react with the magnesium strip. Then, the glass raw material tube is placed in a high-temperature zone of 890 °C, and the purified glass tube is placed in a low-temperature zone of 250 °C for 12 h of distillation purification. This allows the purified materials of Bi, Sb, Se, Te, and As to condense inside the purified glass tube. After purification, the purified glass tube is separated and sealed using an oxyhydrogen flame. 3) Melting, Quenching, and Annealing: The purified glass tube is placed in a swing furnace, and the furnace is heated to 890 °C in stages: First, the temperature of the swing furnace is raised to 350 °C over 3 hours and held for 2 hours; then, the temperature is raised to 650 °C over 3 hours and held for 1 hour; finally, the temperature is raised to 890 °C over 4 hours and held at 890 °C for 22 hours for swing melting to ensure thorough and uniform mixing of the raw materials, allowing the material in the purified glass tube to be swayed and melted into a molten substance. After the swing melting is completed, the temperature of the swing furnace is lowered to 650 °C over 4 hours, and the glass raw material tube is kept vertical for 2 hours. Then, the purified glass tube containing the molten substance is removed from the swing furnace and subjected to air-cooling quenching to solidify the molten substance. After cooling, the purified glass tube is placed in an annealing furnace for annealing at 170 °C for 64 hours. h, to release the internal stress of the glass, after annealing, the germanium-free high refractive index Bi4Sb of Example 4 is obtained. 10 Se 18 Te 50 As 18 Chalcogenide glass.

[0027] It was estimated that preparing 1 kg of Bi4Sb in Example 4 would yield [a specific yield]. 10 Se 18 Te 50 As 18 The cost of chalcogenide glass is approximately 1290 yuan. Tests showed that the Bi4Sb of Example 4, with a thickness of 2 mm,... 10 Se 18 Te 50 As 18 The chalcogenide glass has a refractive index of 3.20 at a wavelength of 10 μm, an infrared window transmittance of 57%, and a density of 5.27 g / cm³. 3 Its performance is superior to that of commercially available high-refractive-index chalcogenide glass.

[0028] As a comparative example, germanium-containing chalcogenide glasses (such as Ge) were prepared using the same grade of raw material purity and a similar preparation process as described in this method. 30 As 13 Se 32 Te 25 The cost per kilogram of the glass is approximately RMB 7,200, which is significantly higher than the cost per kilogram of the glass of this invention (approximately RMB 1,300). The main increase in cost comes from the price of the strategic metal germanium.

Claims

1. A germanium-free high-refractive-index chalcogenide glass, characterized in that, The atomic percentage composition of this chalcogenide glass is as follows: Bi: 1-5%, Sb: 5-15%, Se: 10-20%, Te: 40-60%, As: 10-20%, and the sum of the atomic percentages of each component is 100%. The microstructure of this chalcogenide glass is composed of trigonal pyramidal structural units centered on As, Sb, or Bi atoms and chain-like structures composed of Se or Te atoms.

2. The method for preparing a germanium-free high-refractive-index chalcogenide glass according to claim 1, characterized in that, Includes the following steps: 1) Raw material preparation and loading: According to the atomic percentage composition, weigh out the elemental forms of bismuth, antimony, selenium, tellurium and arsenic as raw materials, mix them in an inert atmosphere to form a mixture, and then load it together with the deoxidizer into the glass raw material tube of a clean and dry H-type double-tube quartz ampoule. The glass raw material tube is connected to the purified glass tube. 2) Vacuum sealing and distillation purification: A vacuum is drawn into the H-type double-tube quartz ampoule while the glass raw material tube is heated at a low temperature until the vacuum level reaches 10. -3 When the pressure is below Pa, the H-type double-tube quartz ampoule is fused and sealed; then the H-type double-tube quartz ampoule is placed in a dual-temperature zone distillation furnace and kept at a constant temperature to allow the oxides in the mixture to react fully with the deoxidizer. Then, the glass raw material tube is placed in the high-temperature zone and the purification glass tube is placed in the low-temperature zone for distillation and purification, causing the purified material to condense inside the purification glass tube; after purification is completed, the purification glass tube is separated and sealed. 3) Melting, quenching and annealing: The purified glass tube is placed in a swing furnace, and the material in the purified glass tube is swung and melted into a molten material. Then, it is quenched by air cooling and then annealed to obtain the germanium-free high refractive index chalcogenide glass.

3. The method for preparing germanium-free high-refractive-index chalcogenide glass according to claim 2, characterized in that, In step 1), the H-type double-tube quartz ampoule undergoes the following pretreatment before filling: the inner wall of the H-type double-tube quartz ampoule is washed with aqua regia and deionized water, and then thoroughly dried.

4. The method for preparing germanium-free high-refractive-index chalcogenide glass according to claim 2, characterized in that, In step 1), the oxygen scavenger is metallic magnesium or metallic aluminum, and the amount of oxygen scavenger added is 0.05-0.3% of the total weight of the mixture.

5. The method for preparing germanium-free high-refractive-index chalcogenide glass according to claim 2, characterized in that, In step 2), during the heat preservation process, the temperature of the glass raw material tube is 600-700 °C, the temperature of the purified glass tube is 750 °C, and the heat preservation time is 8-14 h; during the distillation and purification process, the temperature of the high-temperature zone is 800-900 °C, the temperature of the low-temperature zone is 200-300 °C, and the distillation and purification time is 8-12 h.

6. The method for preparing germanium-free high-refractive-index chalcogenide glass according to claim 2, characterized in that, In step 2), during the vacuuming process, the heating temperature of the glass raw material tube is 80-200 °C.

7. The method for preparing germanium-free high-refractive-index chalcogenide glass according to claim 2, characterized in that, In step 3), the temperature of the rocking melting is 800-900 °C and the time is 12-24 h.

8. The method for preparing a germanium-free high-refractive-index chalcogenide glass according to claim 7, characterized in that, The heating process before the swing melting adopts a segmented heating method: First, the temperature of the swing furnace is raised to 350°C in 3 hours and held for 1-2 hours; then, the temperature of the swing furnace is raised to 650°C in 3 hours and held for 1-2 hours; finally, the temperature of the swing furnace is raised to 800-900°C in 4 hours.

9. The method for preparing a germanium-free high-refractive-index chalcogenide glass according to claim 7, characterized in that, After the swing melting is completed, the temperature of the swing furnace is first reduced to 650 °C over 4 hours, and the glass raw material tube is kept in a vertical position for 2 hours before air cooling quenching.

10. The method for preparing a germanium-free high-refractive-index chalcogenide glass according to claim 2, characterized in that, In step 3), the annealing temperature is 140-180 °C and the annealing time is 48-72 h.

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