A large-size, highly uniform infrared chalcogenide glass and its preparation method and application

Abstract

The present invention relates to the technical field of infrared optical material preparation, and in particular to a large-scale, highly uniform infrared chalcogenide glass, and its preparation method and application. The present invention purifies the raw materials by adopting a low-temperature reduction method or a low-temperature solid fractionation method, thereby effectively reducing the residual impurities in the raw materials and meeting the precision requirements of large-scale infrared chalcogenide glass. The present invention also adopts a method of static solidification in an undercooled atmosphere for cooling and solidification, thereby avoiding the occurrence of stripes or cracks in the infrared chalcogenide glass and improving the quality of the glass blank. The present invention also eliminates the internal thermal stress of the glass material through a process of two annealings combined with a special mold, thereby improving the optical uniformity and transmittance of the infrared chalcogenide glass. The technical solution of the present invention effectively solves the problems of poor raw material purification and high residue in the existing large-scale infrared chalcogenide glass preparation process, and the problem of stripes and cracks easily appearing in the synthesis process, thereby affecting the optical uniformity and internal quality of the infrared chalcogenide glass.

Description

Technical Field

[0001] The present invention relates to the technical field of infrared optical material preparation, and in particular to a large-size, highly uniform infrared chalcogenide glass, a preparation method thereof, and applications thereof. Background Art

[0002] Infrared chalcogenide glass is a type of amorphous infrared optical material based on sulfur (S), selenium (Se), and tellurium (Te) from Group VI of the periodic table, with the introduction of other metallic or non-metallic elements (such as Ge, As, and Sb). Compared to crystalline infrared materials such as single crystals or polycrystalline materials, infrared chalcogenide glass has excellent infrared transmittance, a low temperature coefficient of refractive index, and excellent athermalization. It is an ideal material for thermal and chromatic aberration correction in infrared optical systems and is considered an essential material for implementing passive athermal design and temperature self-adaptation in the next generation of infrared thermal imaging systems. High-quality infrared chalcogenide glass must meet the requirements of high transmittance, low absorption, low impurity content, no streak defects, no cracks, and optical uniformity better than 2×10 -4 Requirements such as these are the key to realizing the design and engineering of key equipment models.

[0003] The preparation process for infrared chalcogenide glass primarily involves four stages: raw material purification, material preparation, synthesis, and annealing heat treatment. The commonly used distillation purification method can meet the low absorption and impurity requirements of small-weight infrared chalcogenide glass, but it struggles to meet the precision requirements of large-scale ingots, often resulting in low distillation efficiency, high levels of residual impurities, and inconsistent loss ratios. The synthesis process determines the internal quality of the infrared chalcogenide glass blank, which in turn affects the effectiveness of the annealing heat treatment in reducing material stress. The synthesis process of infrared chalcogenide glass mostly adopts a combination of high-temperature swing melting, cooling and quenching operations. Among them, the quenching process refers to cooling the temperature to 200-600°C, taking out the quartz bottle containing the melt for rapid cooling, but there are the following problems in the rapid cooling process: infrared chalcogenide glass has poor thermal conductivity, extremely short rapid cooling time, increased instantaneous temperature gradient, inconsistent flow ability, which can easily cause defects and seriously affect the internal quality and optical uniformity of the glass; especially when preparing large-sized chalcogenide glass, the radial size of the infrared chalcogenide glass blank increases, the disadvantage of poor thermal conductivity is further highlighted, the temperature gradient and viscosity gradient are further increased, the difficulty of controlling the melt to not flow is further increased, defects such as cracks and streaks are difficult to control, and disadvantages such as optical inhomogeneity are further highlighted.

[0004] Therefore, the development of a large-size infrared chalcogenide glass that is free of streaks, has stable transmittance, high optical uniformity and low stress is of great significance for the research of infrared optical materials. Summary of the Invention

[0005] In response to the problems that the raw material purification effect is poor and there are many residues in the existing large-scale infrared chalcogenide glass preparation process, and stripes and cracks are easily generated during the synthesis process, which affects the optical uniformity and internal quality of the infrared chalcogenide glass, the present invention provides a large-scale highly uniform infrared chalcogenide glass and its preparation method and application.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A first aspect of the present invention provides a method for preparing large-sized, highly uniform infrared chalcogenide glass, comprising the following steps:

[0008] Step 1: purifying the raw materials by a low-temperature reduction method or a low-temperature solid fractionation method, mixing, and obtaining a purified mixture; the raw materials include at least two of Ge, As, Sb, Se, or Te;

[0009] Step 2: The purified mixture is placed in a quartz tube, vacuum-dried, and the tube mouth is vacuum-sealed, and high-temperature swing melting is performed at 750°C-900°C. After cooling to 300°C-600°C, the quartz tube is placed in a supercooled atmosphere for static solidification to obtain a glass precursor material;

[0010] Step 3: heating the glass precursor material to 20°C-40°C below the glass transition temperature for a first annealing treatment, keeping the temperature, and removing the quartz tube outside the glass precursor material after cooling to room temperature to obtain a glass blank;

[0011] Step 4: placing the glass blank in a mold for precision annealing and slowly cooling to obtain large-sized and highly uniform infrared chalcogenide glass;

[0012] In step 4, the mold includes a ring, an upper cover plate and a lower base plate. When the ratio of the diameter of the glass blank to the thickness of the glass blank is ≥3, the thermal conductivity of the material used for the ring is 0.1Wm -1 K -1 -0.3Wm -1 K -1 When the ratio of the diameter of the glass blank to the thickness of the glass blank is less than 3, the thermal conductivity of the material used in the ring is 100Wm -1 K -1 -150Wm -1 K -1 The thermal conductivity of the material used for the upper cover and lower base is 100Wm -1 K -1 -150Wm -1 K -1 .

[0013] Compared to existing technologies, the present invention utilizes a low-temperature reduction method or a low-temperature solid fractionation method to first purify the raw materials, removing the oxide layer on the raw material surface, reducing impurity content, ensuring the purity consistency and stability of the raw materials during feeding, and improving glass purity. These methods can meet the precision requirements of large-scale ingots, are less likely to produce residual impurities, and offer high extraction efficiency. The present invention also supercools the material after high-temperature swing melting. Compared to water-cooled or air-cooled curing, the static curing process in a supercooled atmosphere is gentler and effectively addresses streak defects that can occur during curing and molding, thereby avoiding the problem of poor internal quality of the glass material and improving the quality of infrared chalcogenide glass.

[0014] During the annealing heat treatment, the present invention creatively proposes a two-step annealing process combined with a special mold to eliminate stress in the glass material. This significantly reduces residual stress within the resulting infrared chalcogenide glass, improves the optical uniformity of the large-scale infrared chalcogenide glass, and makes its performance more stable and reliable. More importantly, the present invention employs a special mold for precision annealing. Depending on the size of the sample, materials with different thermal conductivities are used as the mold ring. For smaller samples, materials with high thermal conductivity are used as the mold ring. This effectively avoids the rapid heat transfer during cooling, which leads to large temperature gradients on the surface and inside of the material and the generation of new stresses. When the ratio of sample diameter to glass blank thickness is large, using a material with low thermal conductivity as the mold ring effectively controls the temperature gradient during precision annealing. The internal and external temperature differences are small, and the generation of thermal stress is relatively insignificant. This helps reduce internal structural defects caused by temperature differences and allows the glass material to cool more evenly, thereby effectively eliminating residual stress and improving optical uniformity.

[0015] In summary, the method for preparing large-scale, highly uniform infrared chalcogenide glass provided by the present invention can produce a large-scale, streak-free, optically uniform, stable transmittance, and low-stress chalcogenide glass product. This method effectively solves the problems of poor raw material purification and high residue in the existing large-scale infrared chalcogenide glass preparation process, as well as the proneness of streaks and cracks during the synthesis process, which in turn affect the optical uniformity and internal quality of the infrared chalcogenide glass. This method provides new ideas for the research and development of large-scale infrared chalcogenide glass.

[0016] Preferably, in step 1, the Ge element is purified by a low-temperature reduction method, the reduction temperature is 700° C.-750° C., and the reduction time is 2 h-4 h.

[0017] Preferably, in step 1, the As element is purified by low-temperature solid fractionation to purify As particles, the fractionation temperature is 200° C.-240° C., and the fractionation time is 1 h-3 h.

[0018] Preferably, in step 1, the purity of each component in the purified mixture is ≥99.9999%.

[0019] Preferably, in step 2, the vacuum drying temperature is 65°C-85°C, the vacuum drying time is 60min-80min, and the vacuum degree of vacuum drying is less than 1×10 -3 Pa.

[0020] Preferably, in step 2, the specific operation of the high-temperature swing melting is: transferring the quartz tube after the tube mouth is sealed to a swing furnace, heating it to 750°C-900°C at a heating rate of 1°C / min-4°C / min, and then performing asymmetrical swinging after constant temperature, and keeping it warm for 8h-20h.

[0021] Further preferably, the tilt angle of the asymmetric swing is -40°-40°, and the swing frequency is 5 times / min-15 times / min.

[0022] Preferably, in step 2, the temperature of the supercooled atmosphere is 60°C-240°C.

[0023] Preferably, in step 2, the static curing time is 1 hour to 3 hours.

[0024] Preferably, in step three, the holding time of the first annealing treatment is 4h-6h.

[0025] Preferably, in step three, the temperature is lowered to room temperature by programmed cooling at a cooling rate of 0.2°C / min-0.5°C / min.

[0026] Preferably, in step 4, the temperature of the precision annealing treatment is 170° C.-400° C., and the holding time of the precision annealing treatment is 10 h-50 h.

[0027] Preferably, in step 4, slow cooling is performed by programmed cooling, with a cooling rate of 0.02°C / min-0.1°C / min.

[0028] Preferably, in step 4, the distance between the edge of the mold and the edge of the glass blank is 2 mm to 5 mm.

[0029] A second aspect of the present invention provides a large-sized, highly uniform infrared chalcogenide glass, which is prepared using the method for preparing the large-sized, highly uniform infrared chalcogenide glass.

[0030] A third aspect of the present invention provides an application of large-scale, highly uniform infrared chalcogenide glass in the preparation of infrared optical materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Flowchart of the process of each embodiment and comparative example;

[0032] Figure 2 Schematic diagram of the structure of the mold used in each embodiment and comparative example; wherein 1 is the mold upper cover plate; 2 is the mold ring; 3 is the mold lower base plate;

[0033] Figure 3 is the transmittance spectrum of Example 1;

[0034] Figure 4 Graphs showing radial stress distribution of large-sized, highly uniform infrared chalcogenide glasses obtained in Example 1 and Comparative Examples 3-4;

[0035] Figure 5 Graphs showing radial stress distribution of large-sized, highly uniform infrared chalcogenide glasses obtained in Example 1 and Comparative Example 5. DETAILED DESCRIPTION

[0036] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0037] Example 1

[0038] This embodiment provides a large-sized and highly uniform infrared chalcogenide glass As 40 Se 60 The preparation method specifically comprises the following steps:

[0039] Step 1: Place 99.9999% pure arsenic particles into a quartz boat, place the quartz boat in a quartz tube, connect the quartz tube to a vacuum deoxidation device, perform a "vacuum-fill with protective gas-vacuum" cycle four times, fully expel the air in the quartz tube, heat to 220°C, keep warm for 2 hours, then cool to room temperature, flush with protective gas to normal pressure, remove the quartz tube in an oxygen-free protective atmosphere, take out the quartz boat and transfer it to an oxygen-free glove box; obtain high-purity As particles; calculate according to Φ130×50mm, weigh 1190.58g of high-purity As particles and 1882.16g of selenium particles in proportion in an oxygen-free glove box, and place them into a Φ130mm diameter quartz tube, where the purity of the selenium particles is 99.9999%;

[0040] Step 2: Connect the quartz tube to a vacuum pump and evacuate to a vacuum of <1×10 -3 Pa, then keep it at 70°C for 1 hour, seal the tube mouth of the quartz container with a hydrogen-oxygen flame, transfer it to a synthesis furnace, heat it to 800°C at a heating rate of 2°C / min, and after constant temperature, perform asymmetrical shaking to mix evenly, and keep it warm for 12 hours; cool it to 450°C, take out the quartz tube, place it in a supercooling range of 60°C and let it stand for 2 hours for supercooling solidification to obtain a glass precursor material;

[0041] Step 3: The glass precursor material is heated to 155° C. for a first annealing treatment, kept at this temperature for 5 hours, and then cooled to room temperature at a rate of 0.3° C. / min. The quartz tube outside the glass precursor material is removed to obtain a cylindrical glass blank with a diameter of 130×40 mm and a flat upper and lower surface;

[0042] Step 4: Place the cylindrical glass blank in a large-diameter mold, then place the large-diameter mold in a precision annealing furnace and heat it to 180°C for precision annealing, keep it warm for 30 hours, and slowly cool it to room temperature at a cooling rate of 0.06°C / min to obtain a large-size, highly uniform infrared chalcogenide glass.

[0043] The internal size of the large diameter mold is 130×45 mm, including a ring, an upper cover plate and a lower base plate. The ring is made of polycrystalline alumina composite fiber board with a thermal conductivity of 0.2Wm -1 K -1 ; The upper cover and lower base are made of graphite with a thermal conductivity of 130Wm -1 K -1 .

[0044] Example 2

[0045] This embodiment provides a large-scale, highly uniform infrared chalcogenide glass Ge 10 As 40 Se 50 The preparation method specifically comprises the following steps:

[0046] Step 1: Place 99.9999% pure arsenic raw material into a quartz boat, place the quartz boat in a quartz tube, connect the quartz tube to a vacuum deoxidation device, and perform a "vacuum-fill with protective gas-vacuum" cycle four times to fully expel the air in the quartz tube. Raise the temperature to 220°C, keep the temperature for 2 hours, then cool to room temperature, flush with protective gas to normal pressure, remove the quartz tube in an oxygen-free protective atmosphere, take out the quartz boat and transfer it to an oxygen-free glove box to obtain high-purity As particles.

[0047] The zone melting germanium ingot is placed in a high-purity quartz boat, placed in a hydrogen reduction furnace, the air is evacuated, argon is introduced for protection, the temperature is raised to 740°C, and then a hydrogen-argon mixture is introduced for reduction for 2 hours, then the temperature is lowered to room temperature, the hydrogen introduction is stopped and argon is introduced, and after 15 minutes, the germanium ingot is taken out in an oxygen-free environment and transferred to an oxygen-free glove box to obtain a high-purity germanium ingot;

[0048] According to the calculation of 180×50mm, 2236.72g high-purity As pellets, 542.16g high-purity germanium ingots and 2946.67g selenium pellets were weighed in proportion in an oxygen-free glove box and placed into a 180mm diameter quartz tube. The purity of the selenium pellets was 99.9999%.

[0049] Step 2: Connect the quartz tube to a vacuum pump and evacuate to a vacuum of <1×10 -3 Pa, then keep it at 70°C for 1 hour, seal the tube mouth of the quartz container with a hydrogen-oxygen flame, transfer it to a synthesis furnace, heat it to 880°C at a heating rate of 1.5°C / min, and after constant temperature, perform asymmetrical shaking to mix evenly and keep it warm for 12 hours; cool it to 500°C, take out the quartz tube, place it in a supercooling range of 90°C and let it stand for 2 hours for supercooling solidification to obtain a glass precursor material;

[0050] Step 3: heating the glass precursor material to 194° C. for a first annealing treatment, keeping the temperature for 5 hours, then cooling the temperature to room temperature at a rate of 0.3° C. / min, and removing the quartz tube outside the glass precursor material to obtain a cylindrical glass blank with a diameter of 180×40 mm and a flat top and bottom surface;

[0051] Step 4: Place the cylindrical glass blank in a large-diameter mold, then place the large-diameter mold in a precision annealing furnace and heat it to 230°C for precision annealing. Keep it warm for 40 hours, and slowly cool it to room temperature at a cooling rate of 0.06°C / min to obtain a large-size, highly uniform infrared chalcogenide glass.

[0052] The internal size of the large diameter mold is 180×45 mm, including a ring, an upper cover plate and a lower base plate. The ring is made of polycrystalline alumina composite fiber board with a thermal conductivity of 0.2 Wm -1 K -1 ; The upper cover and lower base are made of graphite with a thermal conductivity of 130Wm -1 K -1 .

[0053] Example 3

[0054] This embodiment provides a large-scale, highly uniform infrared chalcogenide glass Ge 28 Sb 12 Se 60 The preparation method specifically comprises the following steps:

[0055] Step 1: Place the zone melting germanium ingot into a high-purity quartz boat, place it in a hydrogen reduction furnace, evacuate the air, introduce argon protection, heat it to 740°C, then introduce a hydrogen-argon mixture, reduce it for 2 hours, then cool it to room temperature, stop introducing hydrogen and continue introducing argon, take out the germanium ingot after 15 minutes in an oxygen-free environment, and transfer it to an oxygen-free glove box to obtain a high-purity germanium ingot;

[0056] According to the calculation of Ø120×40mm, 652.47g high-purity germanium ingot, 468.73g antimony particles and 1519.62g selenium particles were weighed proportionally in an oxygen-free glove box and placed into a Ø120mm diameter quartz tube. The purity of the antimony particles and selenium particles were both 99.9999%.

[0057] Step 2: Connect the quartz tube to a vacuum pump and evacuate to a vacuum of <1×10 -3 Pa, then keep it at 70°C for 1 hour, seal the tube mouth of the quartz container with a hydrogen-oxygen flame, transfer it to a synthesis furnace, heat it to 880°C at a heating rate of 2°C / min, and after constant temperature, perform asymmetrical shaking to mix evenly, and keep it warm for 12 hours; cool it to 540°C, take out the quartz tube, place it in a supercooling range of 120°C and let it stand for 2 hours for supercooling solidification to obtain a glass precursor material;

[0058] Step 3: heating the glass precursor material to 250° C. for a first annealing treatment, keeping the temperature for 5 hours, and then cooling it to room temperature at a rate of 0.3° C. / min. removing the quartz tube outside the glass precursor material to obtain a cylindrical glass blank with a diameter of 120×40 mm and a flat top and bottom surface;

[0059] Step 4: Place the cylindrical glass blank in a large-diameter mold, then place the large-diameter mold in a precision annealing furnace and heat it to 180°C for precision annealing, keep it warm for 30 hours, and slowly cool it to room temperature at a cooling rate of 0.06°C / min to obtain a large-size, highly uniform infrared chalcogenide glass.

[0060] The internal size of the large diameter mold is 124×45 mm, including a ring, an upper cover plate and a lower base plate. The ring is made of polycrystalline alumina composite fiber board with a thermal conductivity of 0.2 Wm -1 K -1 ; The upper cover and lower base are made of graphite with a thermal conductivity of 130Wm -1 K -1 .

[0061] Comparative Example 1

[0062] This comparative example provides a large-sized and highly uniform infrared chalcogenide glass As 40 Se 60 The preparation method of Example 1 is different from that of Example 1 in that the arsenic raw material is purified by distillation, and other processes and parameters remain unchanged. The method specifically comprises the following steps:

[0063] Step 1: According to the calculation of Ø130×50mm, 1190.58g of arsenic particles and 1882.16g of selenium were weighed in proportion in an oxygen-free glove box, placed in a double-zone "H" type quartz tube, and vacuumed to <1×10 -3 Pa, then kept warm at 70°C for 1 hour, the tube mouth of the quartz container was sealed with an oxyhydrogen flame, and the sealed tube was placed in a dual-temperature zone distillation furnace. The temperature of the quartz reactor end for collecting the purified material was 200°C, and the temperature of the charging quartz tube end was 900°C for distillation and purification; among them, the purity of the arsenic particles was 99.9999%, and the purity of selenium was 99.9999%; the purified arsenic and selenium were obtained at the quartz reactor end, and the double tubes were sealed with an oxyhydrogen flame.

[0064] Step 2: Transfer the sealed quartz reactor containing the purified arsenic and selenium to a synthesis furnace, heat it to 800°C at a heating rate of 2°C / min, and then asymmetrically shake it to mix it evenly, and keep it warm for 12 hours; cool it to 450°C, remove the quartz tube, and place it in a supercooling range of 60°C for 2 hours for supercooling and solidification to obtain a glass precursor material;

[0065] Step 3: The glass precursor material is heated to 155° C. for a first annealing treatment, kept at this temperature for 5 hours, and then cooled to room temperature at a rate of 0.3° C. / min. The quartz tube outside the glass precursor material is removed to obtain a cylindrical glass blank with a diameter of 130×40 mm and a flat upper and lower surface;

[0066] Step 4: Place the cylindrical glass blank in a large-diameter mold, then place the large-diameter mold in a precision annealing furnace and heat it to 180°C for precision annealing, keep it warm for 30 hours, and slowly cool it to room temperature at a cooling rate of 0.06°C / min to obtain a large-size, highly uniform infrared chalcogenide glass.

[0067] The internal size of the large diameter mold is 130×45 mm, including a ring, an upper cover plate and a lower base plate. The ring is made of polycrystalline alumina composite fiber board with a thermal conductivity of 0.2Wm -1 K -1 ; The upper cover and lower base are made of graphite with a thermal conductivity of 130Wm -1 K -1 .

[0068] Comparative Example 2

[0069] This comparative example provides a large-sized and highly uniform infrared chalcogenide glass As 40 Se 60 The preparation method of the embodiment 1 is different from that of the embodiment 1 in that water cooling is used instead of solidification in a supercooled atmosphere, and other processes and parameters remain unchanged, and specifically comprises the following steps:

[0070] Step 1: Place 99.9999% pure arsenic particles into a quartz boat, place the quartz boat in a quartz tube, connect the quartz tube to a vacuum deoxidation device, perform a "vacuum-fill with protective gas-vacuum" cycle four times, fully expel the air in the quartz tube, heat to 220°C, keep warm for 2 hours, then cool to room temperature, flush with protective gas to normal pressure, remove the quartz tube in an oxygen-free protective atmosphere, take out the quartz boat and transfer it to an oxygen-free glove box; obtain high-purity As particles; calculate according to Φ130×50mm, weigh 1190.58g of arsenic particles and 1882.16g of selenium particles in proportion in an oxygen-free glove box, and place them into a Φ130mm diameter quartz tube, wherein the purity of the selenium particles is 99.9999%;

[0071] Step 2: Connect the quartz tube to a vacuum pump and evacuate to a vacuum of <1×10 -3 Pa, then keep it at 70°C for 1 hour, seal the tube mouth of the quartz container with a hydrogen-oxygen flame, transfer it to a synthesis furnace, heat it to 800°C at a heating rate of 2°C / min, and after constant temperature, perform asymmetrical shaking to mix evenly, and keep it warm for 12 hours; cool it to 450°C, take out the quartz tube, spray it with water to make it cool and solidify quickly, and obtain a glass precursor material;

[0072] Step 3: The glass precursor material is heated to 155° C. for a first annealing treatment, kept at this temperature for 5 hours, and then cooled to room temperature at a rate of 0.3° C. / min. The quartz tube outside the glass precursor material is removed to obtain a cylindrical glass blank with a diameter of 130×40 mm and a flat upper and lower surface;

[0073] Step 4: Place the cylindrical glass blank in a large-diameter mold, then place the large-diameter mold in a precision annealing furnace and heat it to 180°C for precision annealing, keep it warm for 30 hours, and slowly cool it to room temperature at a cooling rate of 0.06°C / min to obtain a large-size, highly uniform infrared chalcogenide glass.

[0074] The internal size of the large diameter mold is 130×45 mm, including a ring, an upper cover plate and a lower base plate. The ring is made of polycrystalline alumina composite fiber board with a thermal conductivity of 0.2Wm -1 K -1 ; The upper cover and lower base are made of graphite with a thermal conductivity of 130Wm -1 K -1 .

[0075] Comparative Example 3

[0076] This comparative example provides a large-sized and highly uniform infrared chalcogenide glass As 40 Se 60 The preparation method of the embodiment 1 is different from that of the embodiment 1 in that air cooling is used instead of curing in a supercooled atmosphere, and other processes and parameters remain unchanged, and specifically comprises the following steps:

[0077] Step 1: Place 99.9999% pure arsenic particles into a quartz boat, place the quartz boat in a quartz tube, connect the quartz tube to a vacuum deoxidation device, perform a "vacuum-fill with protective gas-vacuum" cycle four times, fully expel the air in the quartz tube, heat to 220°C, keep warm for 2 hours, then cool to room temperature, flush with protective gas to normal pressure, remove the quartz tube in an oxygen-free protective atmosphere, take out the quartz boat and transfer it to an oxygen-free glove box; obtain high-purity As particles; calculate according to Φ130×50mm, weigh 1190.58g of arsenic particles and 1882.16g of selenium particles in proportion in an oxygen-free glove box, and place them into a Φ130mm diameter quartz tube, wherein the purity of the selenium particles is 99.9999%;

[0078] Step 2: Connect the quartz tube to a vacuum pump and evacuate to a vacuum of <1×10 -3 Pa, then keep it at 70℃ for 1h, seal the tube mouth of the quartz container with a hydrogen-oxygen flame, transfer it to a synthesis furnace, heat it to 800℃ at a heating rate of 2℃ / min, and after constant temperature, perform asymmetrical shaking to mix evenly, and keep it warm for 12h; cool it to 450℃, take out the quartz tube, send it to a cooling furnace, and ventilate it for cooling and solidification at a ventilation rate of 1NL / min to obtain a glass precursor material;

[0079] Step 3: The glass precursor material is heated to 155° C. for a first annealing treatment, kept at this temperature for 5 hours, and then cooled to room temperature at a rate of 0.3° C. / min. The quartz tube outside the glass precursor material is removed to obtain a cylindrical glass blank with a diameter of 130×40 mm and a flat upper and lower surface;

[0080] Step 4: Place the cylindrical glass blank in a large-diameter mold, then place the large-diameter mold in a precision annealing furnace and heat it to 180°C for precision annealing, keep it warm for 30 hours, and slowly cool it to room temperature at a cooling rate of 0.06°C / min to obtain a large-size, highly uniform infrared chalcogenide glass.

[0081] The internal size of the large diameter mold is 130×45 mm, including a ring, an upper cover plate and a lower base plate. The ring is made of polycrystalline alumina composite fiber board with a thermal conductivity of 0.2Wm -1 K -1 ; The upper cover and lower base are made of graphite with a thermal conductivity of 130Wm -1 K -1 .

[0082] Comparative Example 4

[0083] This comparative example provides a large-sized and highly uniform infrared chalcogenide glass As 40 Se 60 The preparation method of the embodiment 1 is different from that of the embodiment 1 in that the precision annealing is performed in a moldless manner, and other processes and parameters remain unchanged, and specifically includes the following steps:

[0084] Step 1: Place 99.9999% pure arsenic particles into a quartz boat, place the quartz boat in a quartz tube, connect the quartz tube to a vacuum deoxidation device, perform a "vacuum-fill with protective gas-vacuum" cycle four times, fully expel the air in the quartz tube, heat to 220°C, keep warm for 2 hours, then cool to room temperature, flush with protective gas to normal pressure, remove the quartz tube in an oxygen-free protective atmosphere, take out the quartz boat and transfer it to an oxygen-free glove box; obtain high-purity As particles; calculate according to Φ130×50mm, weigh 1190.58g of arsenic particles and 1882.16g of selenium particles in proportion in an oxygen-free glove box, and place them into a Φ130mm diameter quartz tube, wherein the purity of the selenium particles is 99.9999%;

[0085] Step 2: Connect the quartz tube to a vacuum pump and evacuate to a vacuum of <1×10 -3 Pa, then keep it at 70°C for 1 hour, seal the tube mouth of the quartz container with a hydrogen-oxygen flame, transfer it to a synthesis furnace, heat it to 800°C at a heating rate of 2°C / min, and after constant temperature, perform asymmetrical shaking to mix evenly, and keep it warm for 12 hours; cool it to 450°C, take out the quartz tube, place it in a supercooling range of 60°C and let it stand for 2 hours for supercooling solidification to obtain a glass precursor material;

[0086] Step 3: The glass precursor material is heated to 155° C. for a first annealing treatment, kept at this temperature for 5 hours, and then cooled to room temperature at a rate of 0.3° C. / min. The quartz tube outside the glass precursor material is removed to obtain a cylindrical glass blank with a diameter of 130×40 mm and a flat upper and lower surface;

[0087] Step 4: Place the cylindrical glass blank in a precision annealing furnace, heat it to 180° C. for precision annealing, keep it warm for 30 hours, and slowly cool it to room temperature at a cooling rate of 0.06° C. / min to obtain a large-sized, highly uniform infrared chalcogenide glass.

[0088] In order to further demonstrate the technical effects of the present invention, the large-size, highly uniform infrared chalcogenide glasses obtained in Examples 1-3 and Comparative Examples 1-4 of the present invention were subjected to the following tests: stress tests were performed on the samples obtained in each Example and Comparative Example with reference to the national standard GB / T32561.5-2022; striae tests were performed on the samples obtained in each Example and Comparative Example with reference to the national standard GB / T32561.2-2016; uniformity tests were performed on the samples obtained in each Example and Comparative Example with reference to the national standard GB / T36265-2018; refractive index tests were performed on the samples obtained in each Example and Comparative Example with reference to the national standard GB / T34184-2017; bending strength tests were performed on the samples obtained in each Example and Comparative Example with reference to the national standard GB / T6569-2006; and hardness tests were performed on the samples obtained in each Example and Comparative Example with reference to the national standard GB / 16534-2009. The test results are shown in Tables 1 and Figure 3-5 shown.

[0089] Table 1 Performance test results of samples obtained from various embodiments and comparative examples

[0090]

[0091] According to Table 1 and Figure 3-5 It can be seen that the transmittance of the sample obtained in Example 1 in the 2μm-16μm band is ≥50%, and the absorption of -OH, HOH, As-O, Se-O, etc. is significantly reduced; the amplitude of the stress change of the 20mm thick sample of Example 1 after curing is significantly reduced; after precision annealing in the mold, the stress of Example 1 is significantly reduced, and the stress value of the 20mm thick sample is reduced to below 50nm. In the comparative example, the refractive index of the sample obtained by distillation purification of the raw materials in Comparative Example 1 fluctuates greatly and is unstable; the number of periodic fluctuations in the radial stress distribution of Comparative Examples 2 and Comparative Examples 3 increases significantly. Within one cycle, the stress value is an accurate measurement value. After exceeding one cycle, it is shown that the density of periodic fluctuations represents the relative central stress value. That is, the denser the fluctuations, the greater the stress value. From the analysis of the radial stress distribution, the faster the fluctuations are towards the edge, the greater the actual stress value; Comparative Example 4, after mold-free precision annealing, has no periodic fluctuations, but the radial stress varies greatly, and the maximum value is significantly higher than that of Example 1.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing large-scale, highly uniform infrared chalcogenide glass, characterized by: The steps include: Step 1: purifying the raw materials by a low-temperature reduction method or a low-temperature solid fractionation method, mixing, and obtaining a purified mixture; the raw materials include at least two of Ge, As, Sb, Se, or Te; Step 2: The purified mixture is placed in a quartz tube, vacuum-dried, and the tube mouth is vacuum-sealed, and high-temperature swing melting is performed at 750°C-900°C. After cooling to 300°C-600°C, the quartz tube is placed in a supercooled atmosphere for static solidification to obtain a glass precursor material; Step 3: heating the glass precursor material to 20°C-40°C below the glass transition temperature for a first annealing treatment, keeping the temperature, and removing the quartz tube outside the glass precursor material after cooling to room temperature to obtain a glass blank; Step 4: placing the glass blank in a mold for precision annealing and slowly cooling to obtain large-sized and highly uniform infrared chalcogenide glass; In step 4, the mold includes a ring, an upper cover plate and a lower base plate. When the ratio of the diameter of the glass blank to the thickness of the glass blank is ≥3, the thermal conductivity of the material used for the ring is 0.1Wm -1 K -1 -0.3Wm -1 K -1 When the ratio of the diameter of the glass blank to the thickness of the glass blank is less than 3, the thermal conductivity of the material used in the ring is 100Wm -1 K -1 -150Wm -1 K -1 The thermal conductivity of the material used for the upper cover and lower base is 100Wm -1 K -1 -150Wm -1 K -1 ; In step 1, the Ge element is purified by a low-temperature reduction method, the reduction temperature is 700° C.-750° C., and the reduction time is 2 h-4 h; In step 1, the As element is purified by low-temperature solid fractionation to purify As particles, the fractionation temperature is 200° C.-240° C., and the fractionation time is 1 h-3 h.

2. The method for preparing large-sized, highly uniform infrared chalcogenide glass according to claim 1, wherein: In step 1, the purity of each component in the purified mixture is ≥99.9999%.

3. The method for preparing large-sized, highly uniform infrared chalcogenide glass according to claim 1, wherein: In step 2, the vacuum drying temperature is 65°C-85°C, the vacuum drying time is 60min-80min, and the vacuum degree of vacuum drying is less than 1×10 -3 Pa.

4. The method for preparing large-sized, highly uniform infrared chalcogenide glass according to claim 1, wherein: In step 2, the specific operation of the high-temperature swing melting is: transfer the quartz tube with the tube mouth sealed to a swing furnace, heat it to 750℃-900℃ at a heating rate of 1℃ / min-4℃ / min, and then perform asymmetrical swinging after constant temperature, and keep it warm for 8h-20h.

5. The method for preparing large-sized, highly uniform infrared chalcogenide glass according to claim 4, wherein: The tilt angle of the asymmetric swing is -40° to 40°, and the swing frequency is 5 times / min to 15 times / min.

6. The method for preparing large-sized, highly uniform infrared chalcogenide glass according to claim 1, wherein: In step 2, the temperature of the supercooled atmosphere is 60°C-240°C; and / or In step 2, the static curing time is 1 hour to 3 hours.

7. The method for preparing large-sized, highly uniform infrared chalcogenide glass according to claim 1, wherein: In step 3, the holding time of the first annealing treatment is 4h-6h; and / or In step 3, the temperature is lowered to room temperature by programmed cooling at a rate of 0.2°C / min-0.5°C / min.

8. The method for preparing large-sized, highly uniform infrared chalcogenide glass according to claim 1, wherein: In step 4, the temperature of the precision annealing treatment is 170°C-400°C, and the holding time of the precision annealing treatment is 10h-50h; and / or In step 4, the mixture is slowly cooled by programmed cooling at a rate of 0.02°C / min to 0.1°C / min; and / or In step 4, the distance between the edge of the mold and the edge of the glass blank is 2 mm to 5 mm.

9. A large-scale, highly uniform infrared chalcogenide glass, characterized by: The large-sized, highly uniform infrared chalcogenide glass is prepared by the preparation method of any one of claims 1 to 8.

10. Use of the large-sized, highly uniform infrared chalcogenide glass according to claim 9 in the preparation of infrared optical materials.

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