Radiation resistant low expansion fluoride glass and method of making same

Abstract

The application discloses a kind of radiation-resistant low-expansion fluoride glass and its preparation method, it is related to new type glass technical field.The fluoride glass provided in the application all component ingredients are fluorine-containing compounds, including ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3And Na3AlF6, the mole percentage of each component is (40~55) :(10~15) :(10~15) :(5~10) :(5~10) :(2~5) :(3~5) :(5~10) :(5~10).The above raw materials are dried in vacuum, grinded and screened, ball milled, tube furnace melting, shaping, annealing treatment and other steps in the application, and excellent fluoride glass is prepared, and the preparation process of the application can reduce the impurities and internal stress in the prepared fluoride glass, ensure the stable performance of glass, and be suitable for optical, radiation-resistant and other related fields.

Description

Technical Field

[0001] This application relates to the field of novel glass technology, and in particular to a radiation-resistant, low-expansion fluoride glass and its preparation method. Background Technology

[0002] Fluoride glasses possess significant potential for application in related fields due to their excellent optical transmittance. However, existing fluoride glasses generally suffer from insufficient radiation resistance. Prolonged exposure to radiation environments can lead to the accumulation of lattice defects, resulting in decreased transmittance and deterioration of structural stability. Furthermore, some products have a high coefficient of thermal expansion, making them prone to deformation or even cracking under temperature fluctuations, thus affecting device lifespan. Simultaneously, improper handling of fluorine-containing raw materials in traditional manufacturing processes can further exacerbate the defects in the mechanical and optical properties of fluoride glasses, making them unsuitable for the stability and reliability requirements of high-end applications. Therefore, to meet the increasingly stringent performance requirements of glass materials in fields such as optical engineering, radiation detection, and high-temperature environment devices, developing fluoride glasses with optimized composition, excellent radiation resistance, and low expansion characteristics, and constructing manufacturing processes that effectively control impurities and reduce internal stress, has become an important research direction in the field of fluoride glass materials. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this application provides a radiation-resistant, low-expansion fluoride glass and its preparation method. This application involves processing various fluoride raw materials through vacuum drying, grinding and sieving, ball milling, tube furnace melting, forming, and annealing to obtain a high-performance fluoride glass. Furthermore, the preparation process of this application can reduce impurities and internal stress in the obtained fluoride, ensuring stable glass performance, making it suitable for optical, radiation-resistant, and other related fields.

[0004] To achieve the above objectives, this application adopts the following technical solution:

[0005] In a first aspect, this application provides a radiation-resistant, low-expansion fluoride glass, wherein all components of the radiation-resistant, low-expansion fluoride glass are fluorine-containing compounds; the fluorine-containing compounds include: ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3 and Na3AlF6; the molar percentages of ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3 and Na3AlF6 are: (40~55): (10~15): (10~15): (5~10): (5~10): (2~5): (3~5): (5~10): (5~10).

[0006] By using specific ratios of fluorine-containing compounds, glass can achieve a low coefficient of thermal expansion, high radiation resistance, and good chemical stability.

[0007] In this application, ZrF4 forms the framework of the fluoride glass network, where the rigid structure of the Zr-F bonds provides fundamental stability. Furthermore, CaF2, BaF2, and SrF2 serve as crystal network modifiers, introducing larger Ca atoms... 2+ Ba 2+ and Sr 2+ Ions fill the gaps in the crystal network, suppressing the crystal volume expansion caused by thermal vibrations induced by radiation. Simultaneously, the addition of LiF, NaF, AlF3, and Na3AlF6 introduces small-sized lithium, sodium, and aluminum ions, further filling the gaps in the crystal network. These ions, in conjunction with ZrF4, BaF2, and SrF2, act like adding pebbles and sand to a container already full of large rocks, promoting the densification of the crystal network in the fluoride glass and thus further reducing its coefficient of thermal expansion. Furthermore, the bonding between various metal ions and fluoride ions significantly enhances the structural rigidity of the resulting fluoride glass crystal network, thereby reducing radiation-induced structural defects and improving radiation resistance. Finally, Ce is introduced into the fluoride glass via CeF3, due to its unique 4f outer electron configuration. 1 5d 1 6s 2 Therefore, Ce can exist stably in fluoride glasses. 3+ and Ce 4+ It has two valence states, and these two valence states can be interconverted by capturing free electrons and holes generated by radiation, thereby blocking the formation of crystal color centers and further improving the radiation resistance.

[0008] Secondly, this application provides a method for preparing radiation-resistant, low-expansion fluoride glass, comprising the following steps:

[0009] S1. Place each component of the fluorine-containing compound into a crucible, place the crucible into a vacuum drying oven, and dry to obtain the dried raw material;

[0010] S2. Transfer the dried raw material to a mortar, grind it, and then pass it through a nylon sieve to obtain the sieved raw material.

[0011] S3. After mixing the weighed and screened raw materials according to the proportion, add them to the agate ball mill jar, add the ball milling media, control the ball-to-material ratio and ball milling speed, and ball mill under inert gas protection to obtain the mixed raw materials.

[0012] S4. Load the mixed raw materials into a crucible, place it in a tube furnace, and introduce inert gas. First, purge at the first flow rate for 30-60 minutes, and then maintain the second flow rate for continuous gas introduction.

[0013] S5. Raise the temperature of the tube furnace from room temperature to 400°C at the first heating rate, hold for 1-2 hours, then continue to raise the temperature to 700°C at the second heating rate and hold for 2-3 hours to obtain molten mixed raw materials.

[0014] S6. Pour the molten mixed raw materials into the preheated mold while hot, and let it cool naturally to room temperature to obtain the shaped glass;

[0015] S7. Place the formed glass and the mold together into an annealing furnace, and after annealing, obtain the radiation-resistant, low-expansion fluoride glass.

[0016] In one feasible implementation scheme, the specific drying parameters in S1 are: temperature 120~150℃, pressure 10~50Pa, and drying time 4~6h.

[0017] In this application, the drying temperature is higher than the boiling point of water but lower than the decomposition temperature of the fluoride used. Combined with the low-pressure environment of the vacuum drying oven, this ensures rapid removal of moisture and prevents the generation of HF gas during subsequent high-temperature processing from corroding the glass structure.

[0018] In one feasible implementation scheme, in S2, the grinding time is 1 to 2 hours, and the nylon sieve has a mesh size of 100 to 200.

[0019] In this application, ball milling under inert gas protection after dehydration can prevent the fluoride raw material from reacting; grinding and crushing the raw material particles and sieving to remove coarse particles can prevent uneven local raw material composition or the generation of unmelted residue during melting.

[0020] In one feasible implementation scheme, in S3, the ball-to-material ratio is 3:1, the ball milling speed is 200~300 r / min, and the ball milling time is 2~4 h.

[0021] A ball-to-material ratio of 3:1 provides sufficient mechanical impact to break up agglomerates in the raw materials; a moderate rotation speed can prevent excessive heat from causing structural damage to the glass raw material components; and controlling the ball milling time can balance the dispersion effect and energy consumption, and also prevent over-grinding from introducing other impurities.

[0022] In one feasible implementation, in S3 and S4, the inert gas includes any one of nitrogen, argon, and a mixture of nitrogen and argon; in the mixture of nitrogen and argon, the volume ratio of nitrogen to argon is (20~30):(70~80).

[0023] In one feasible implementation, in S4, the first flow rate is 50-60 mL / min and the second flow rate is 20-30 mL / min.

[0024] Using nitrogen, argon, or a mixture of both, a rapid purging followed by stable ventilation can effectively isolate oxygen and moisture.

[0025] In one feasible implementation, in S5, the first heating rate is 5~10℃ / min, and the second heating rate is 30~50℃ / min.

[0026] In this application, the slow heating from room temperature to 400°C can prevent the raw materials from cracking due to thermal stress; the accelerated heating from 400°C to 700°C can reduce the decomposition and volatilization of raw material components at high temperatures.

[0027] In one feasible implementation, in S6, the preheated mold includes either a graphite mold or a silicon carbide mold; the preheating temperature is 300~400℃.

[0028] In this application, a graphite mold or silicon carbide mold with a thermal conductivity far higher than that of ordinary molds is used. During preheating, the graphite mold or silicon carbide mold can quickly absorb heat and the overall temperature is uniform. Therefore, after the molten glass is poured in, the mold can conduct heat out evenly, avoiding uneven temperature at the interface between the glass and the mold. This can reduce the stress of the molten fluoride during molding and thus prevent cracks from forming.

[0029] In one feasible implementation, in S7, the annealing process includes:

[0030] First, raise the temperature to 350-400℃ at a rate of 5-10℃ / min, then keep it at that temperature for 2-4 hours. Finally, lower the temperature to 100℃ at a rate of 1-2℃ / min, and then remove it and let it cool naturally to room temperature.

[0031] The further annealing process in this application involves first heating the glass to 350-400°C, which can relax the internal structure of the glass and, combined with sufficient heat preservation time, fully release the stress; then, the glass is slowly cooled to avoid the formation of secondary stress.

[0032] Beneficial technical effects:

[0033] This application utilizes ZrF4 to form the framework of a fluoride glass network, where the rigid structure of the Zr-F bonds provides fundamental stability. Furthermore, CaF2, BaF2, and SrF2 are used as crystal network modifiers, introducing larger Ca atoms... 2+ Ba 2+ and Sr 2+Ions fill the gaps in the crystal network, suppressing the crystal volume expansion caused by thermal vibrations induced by radiation. Simultaneously, the addition of LiF, NaF, AlF3, and Na3AlF6 introduces small-sized lithium, sodium, and aluminum ions, further filling the gaps in the crystal network. These ions, in conjunction with ZrF4, BaF2, and SrF2, act like adding pebbles and sand to a container already full of large rocks, promoting the densification of the crystal network in the fluoride glass and thus further reducing its coefficient of thermal expansion. Furthermore, the bonding between various metal ions and fluoride ions significantly enhances the structural rigidity of the resulting fluoride glass crystal network, thereby reducing radiation-induced structural defects and improving radiation resistance. Finally, Ce is introduced into the fluoride glass via CeF3, due to its unique 4f outer electron configuration. 1 5d 1 6s 2 Therefore, Ce can exist stably in fluoride glasses. 3+ and Ce 4+ The two valence states can interconvert by capturing free electrons and holes generated by radiation, thereby blocking the formation of crystal color centers and further improving radiation resistance. Simultaneously, by combining raw material dehydration and ball milling for homogenization, effective inert atmosphere protection during melting, the use of matching graphite or silicon carbide molds, and temperature control during annealing, the resulting fluoride glass possesses radiation resistance, low expansion, high chemical stability, and structural integrity, making it suitable for various demanding applications. Attached Figure Description

[0034] Figure 1 This is a schematic flowchart of a method for preparing radiation-resistant, low-expansion fluoride glass according to an embodiment of this application. Detailed Implementation

[0035] To facilitate understanding of the content described in this application, the technical solutions described herein are further explained below with reference to specific embodiments; however, this application is not limited thereto. All equivalent transformations or simple substitutions made based on the substantive content of this application should fall within the protection scope of this application.

[0036] The singular forms “for,” “or,” “a,” “any,” and “the” used in this application are intended to include the plural forms unless the context clearly indicates otherwise.

[0037] The following describes in detail, with reference to different embodiments, the preparation method of the radiation-resistant, low-expansion fluoride glass provided in this application.

[0038] Example 1

[0039] like Figure 1As shown, a method for preparing radiation-resistant, low-expansion fluoride glass includes the following steps:

[0040] S1. Place ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3, and Na3AlF6 into crucibles respectively, and place the crucibles in a vacuum drying oven to obtain dried raw materials. The molar percentages of ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3, and Na3AlF6 are 45:12:12:7:6:3:4:6:5. The specific parameters for vacuum drying are: temperature 130℃, pressure 20Pa, and drying time 5h.

[0041] S2. Transfer the dried raw material to a mortar, grind it, and then pass it through a nylon sieve to obtain the sieved raw material; the grinding time is 1.5 hours, and the nylon sieve has a mesh size of 150.

[0042] S3. After mixing the weighed and screened raw materials according to the ratio, add them to the agate ball mill jar, add the ball milling media, control the ball-to-material ratio and the ball milling speed, and ball mill under nitrogen protection to obtain the mixed raw materials; wherein, the ball-to-material ratio is 3:1, the ball milling speed is 250 r / min, and the ball milling time is 3h;

[0043] S4. Load the mixed raw materials into a crucible, place it in a tube furnace, and purge with nitrogen gas. First, purge with a first flow rate of 55 mL / min for 45 min, and then maintain a second flow rate of 25 mL / min for continuous purging.

[0044] S5. The temperature of the tube furnace is raised from room temperature to 400°C at a first heating rate of 8°C / min, held for 1.5 hours, and then raised to 700°C at a second heating rate of 40°C / min and held for 2.5 hours to obtain molten mixed raw materials.

[0045] S6. Pour the molten mixed raw materials into a graphite mold preheated to 350°C while hot, and let it cool naturally to room temperature to obtain the shaped glass.

[0046] S7. The formed glass and the mold are placed together in an annealing furnace and annealed to obtain the radiation-resistant low-expansion fluoride glass. The annealing process includes: first heating to 380°C at a rate of 8°C / min, then holding at that temperature for 3 hours, and finally cooling to 100°C at a rate of 1.5°C / min, and then taking it out and letting it cool naturally to room temperature.

[0047] Example 2

[0048] like Figure 1 As shown, a method for preparing radiation-resistant, low-expansion fluoride glass includes the following steps:

[0049] S1. Place ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3, and Na3AlF6 into crucibles respectively, and place the crucibles in a vacuum drying oven to obtain dried raw materials. The molar percentages of ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3, and Na3AlF6 are 40:15:10:5:5:5:5:5:10. The specific parameters for vacuum drying are: temperature 120℃, pressure 10Pa, and drying time 6h.

[0050] S2. Transfer the dried raw material to a mortar, grind it, and then pass it through a nylon sieve to obtain the sieved raw material; the grinding time is 2 hours, and the nylon sieve has a mesh size of 200.

[0051] S3. After mixing the weighed and screened raw materials according to the ratio, add them to the agate ball mill jar, add the ball milling media, control the ball-to-material ratio and the ball milling speed, and ball mill under nitrogen protection to obtain the mixed raw materials; wherein, the ball-to-material ratio is 3:1, the ball milling speed is 200 r / min, and the ball milling time is 4 h;

[0052] S4. Load the mixed raw materials into a crucible, place it in a tube furnace, and purge with nitrogen gas. First, purge with a first flow rate of 50 mL / min for 60 min, and then maintain a second flow rate of 20 mL / min for continuous purging.

[0053] S5. The temperature of the tube furnace is raised from room temperature to 400°C at a first heating rate of 5°C / min, held for 2 hours, and then raised to 700°C at a second heating rate of 30°C / min and held for 3 hours to obtain molten mixed raw materials.

[0054] S6. Pour the molten mixed raw materials into a silicon carbide mold preheated to 300°C while hot, and let it cool naturally to room temperature to obtain the shaped glass.

[0055] S7. The formed glass and the mold are placed together in an annealing furnace and annealed to obtain the radiation-resistant low-expansion fluoride glass. The annealing process includes: first heating to 350°C at a rate of 5°C / min, then holding at that temperature for 4 hours, and finally cooling to 100°C at a rate of 1°C / min, and then taking it out and letting it cool naturally to room temperature.

[0056] Example 3

[0057] like Figure 1 As shown, a method for preparing radiation-resistant, low-expansion fluoride glass includes the following steps:

[0058] S1. Place ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3, and Na3AlF6 into crucibles respectively, place the crucibles in a vacuum drying oven, and dry to obtain the dried raw material; wherein, the molar percentage of ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3, and Na3AlF6 is 45:10:10:10:5:2:3:8:7; the specific parameters for vacuum drying are: temperature 150℃, pressure 50Pa, and drying time 4h;

[0059] S2. Transfer the dried raw material to a mortar, grind it, and then pass it through a nylon sieve to obtain the sieved raw material; the grinding time is 1 hour, and the nylon sieve has a mesh size of 100.

[0060] S3. After mixing the weighed and screened raw materials according to the ratio, add them to the agate ball mill jar, add the ball milling media, control the ball-to-material ratio and the ball milling speed, and ball mill under the protection of a mixed gas of nitrogen and argon to obtain the mixed raw materials; wherein, the ball-to-material ratio is 3:1, the ball milling speed is 300 r / min, the ball milling time is 2h; the volume ratio of nitrogen to argon is 25:75;

[0061] S4. Load the mixed raw materials into a crucible, place it in a tube furnace, and purge with a mixture of nitrogen and argon. First, purge with a first flow rate of 60 mL / min for 30 min, and then maintain a second flow rate of 30 mL / min for continuous purging; the volume ratio of nitrogen to argon is 25:75.

[0062] S5. The temperature of the tube furnace is raised from room temperature to 400°C at a first heating rate of 10°C / min, held for 1 hour, and then raised to 700°C at a second heating rate of 50°C / min and held for 2 hours to obtain molten mixed raw materials.

[0063] S6. Pour the molten mixed raw materials into a graphite mold preheated to 400°C while hot, and let it cool naturally to room temperature to obtain the shaped glass.

[0064] S7. The formed glass and the mold are placed together in an annealing furnace and annealed to obtain the radiation-resistant low-expansion fluoride glass. The annealing process includes: first heating to 400°C at a rate of 10°C / min, then holding at that temperature for 2 hours, and finally cooling to 100°C at a rate of 2°C / min, and then taking it out and letting it cool naturally to room temperature.

[0065] Example 4

[0066] like Figure 1 As shown, a method for preparing radiation-resistant, low-expansion fluoride glass includes the following steps:

[0067] S1. Place ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3, and Na3AlF6 into crucibles respectively, and place the crucibles in a vacuum drying oven to obtain dried raw materials. The molar percentages of ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3, and Na3AlF6 are 55:10:10:5:5:2:3:5:5. The specific parameters for vacuum drying are: temperature 135℃, pressure 30Pa, and drying time 4.5h.

[0068] S2. Transfer the dried raw material to a mortar, grind it, and then pass it through a nylon sieve to obtain the sieved raw material; the grinding time is 1.5 hours, and the nylon sieve has a mesh size of 150.

[0069] S3. After mixing the weighed and screened raw materials according to the ratio, add them to the agate ball mill jar, add the ball milling media, control the ball-to-material ratio and the ball milling speed, and ball mill under the protection of a mixed gas of nitrogen and argon to obtain the mixed raw materials; wherein, the ball-to-material ratio is 3:1, the ball milling speed is 250 r / min, the ball milling time is 2.5 h, and the volume ratio of nitrogen to argon is 20:80;

[0070] S4. Load the mixed raw materials into a crucible, place it in a tube furnace, and purge with a mixture of nitrogen and argon. First, purge with a first flow rate of 55 mL / min for 40 min, and then maintain a second flow rate of 25 mL / min for continuous purging; the volume ratio of nitrogen to argon is 20:80.

[0071] S5. The temperature of the tube furnace is raised from room temperature to 400°C at a first heating rate of 8°C / min, held for 1.5 hours, and then raised to 700°C at a second heating rate of 45°C / min and held for 2.5 hours to obtain molten mixed raw materials.

[0072] S6. Pour the molten mixed raw materials into a silicon carbide mold preheated to 350°C while hot, and let it cool naturally to room temperature to obtain the shaped glass.

[0073] S7. The formed glass and the mold are placed together in an annealing furnace and annealed to obtain the radiation-resistant low-expansion fluoride glass. The annealing process includes: first heating to 350°C at a rate of 8°C / min, then holding at that temperature for 2.5 hours, and finally cooling to 100°C at a rate of 1.5°C / min, and then taking it out and letting it cool naturally to room temperature.

[0074] Example 5

[0075] like Figure 1 As shown, a method for preparing radiation-resistant, low-expansion fluoride glass includes the following steps:

[0076] S1. Place ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3, and Na3AlF6 into crucibles respectively, and place the crucibles in a vacuum drying oven to obtain dried raw materials. The molar percentages of ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3, and Na3AlF6 are 46:10:12:5:5:3:4:10:5. The specific parameters for vacuum drying are: temperature 140℃, pressure 40Pa, and drying time 5.5h.

[0077] S2. Transfer the dried raw material to a mortar, grind it, and then pass it through a nylon sieve to obtain the sieved raw material; the grinding time is 1.5 hours, and the nylon sieve has a mesh size of 120.

[0078] S3. After mixing the weighed and screened raw materials according to the ratio, add them to the agate ball mill jar, add the ball milling media, control the ball-to-material ratio and the ball milling speed, and ball mill under the protection of a mixed gas of nitrogen and argon to obtain the mixed raw materials; wherein, the ball-to-material ratio is 3:1, the ball milling speed is 200 r / min, the ball milling time is 3.5 h; the volume ratio of nitrogen to argon is 30:70;

[0079] S4. Load the mixed raw materials into a crucible, place it in a tube furnace, and purge with a mixture of nitrogen and argon gas. First, purge with a first flow rate of 50 mL / min for 50 min, and then maintain a second flow rate of 20 mL / min for continuous purging; the volume ratio of nitrogen to argon is 30:70.

[0080] S5. The temperature of the tube furnace is raised from room temperature to 400°C at a first heating rate of 5°C / min, held for 2 hours, and then raised to 700°C at a second heating rate of 40°C / min and held for 3 hours to obtain molten mixed raw materials.

[0081] S6. Pour the molten mixed raw materials into a graphite mold preheated to 320°C while hot, and let it cool naturally to room temperature to obtain the shaped glass.

[0082] S7. The formed glass and the mold are placed together in an annealing furnace and annealed to obtain the radiation-resistant low-expansion fluoride glass. The annealing process includes: first heating to 360°C at a rate of 5°C / min, then holding at that temperature for 3.5 hours, and finally cooling to 100°C at a rate of 1°C / min, and then taking it out and letting it cool naturally to room temperature.

[0083] Example 6

[0084] like Figure 1 As shown, a method for preparing radiation-resistant, low-expansion fluoride glass includes the following steps:

[0085] S1. Place ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3, and Na3AlF6 into crucibles respectively, and place the crucibles in a vacuum drying oven to obtain dried raw materials. The molar percentages of ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3, and Na3AlF6 are 43:12:13:7:5:2:5:6:7. The specific parameters for vacuum drying are: temperature 125℃, pressure 25Pa, and drying time 5h.

[0086] S2. Transfer the dried raw material to a mortar, grind it, and then pass it through a nylon sieve to obtain the sieved raw material; the grinding time is 2 hours, and the nylon sieve has a mesh size of 180 mesh;

[0087] S3. After mixing the weighed and screened raw materials according to the ratio, add them to the agate ball mill jar, add the ball milling media, control the ball-to-material ratio and the ball milling speed, and ball mill under argon protection to obtain the mixed raw materials; wherein, the ball-to-material ratio is 3:1, the ball milling speed is 250 r / min, and the ball milling time is 3h;

[0088] S4. Load the mixed raw materials into a crucible, place it in a tube furnace, and purge with argon gas. First, purge with a first flow rate of 50 mL / min for 40 min, and then maintain a second flow rate of 25 mL / min for continuous purging.

[0089] S5. The temperature of the tube furnace is raised from room temperature to 400°C at a first heating rate of 5°C / min, held for 1.5 hours, and then raised to 700°C at a second heating rate of 45°C / min and held for 2 hours to obtain molten mixed raw materials.

[0090] S6. Pour the molten mixed raw materials into a silicon carbide mold preheated to 360°C while hot, and let it cool naturally to room temperature to obtain the shaped glass.

[0091] S7. The formed glass and the mold are placed together in an annealing furnace and annealed to obtain the radiation-resistant low-expansion fluoride glass. The annealing process includes: first heating to 350°C at a rate of 5°C / min, then holding at that temperature for 3 hours, and finally cooling to 100°C at a rate of 1.5°C / min, and then taking it out and letting it cool naturally to room temperature.

[0092] Comparative Example 1

[0093] A method for preparing radiation-resistant, low-expansion fluoride glass includes the following steps:

[0094] S1. Place ZrF4, BaF2, SrF2, CaF2, and CeF3 into crucibles respectively, place the crucibles in a vacuum drying oven, and dry to obtain the dried raw material; wherein, the molar percentage of ZrF4, BaF2, SrF2, CaF2, and CeF3 is 55:15:15:5:10; the specific parameters for vacuum drying are: temperature 130℃, pressure 20Pa, and drying time 5h;

[0095] S2. Transfer the dried raw material to a mortar, grind it, and then pass it through a nylon sieve to obtain the sieved raw material; the grinding time is 1.5 hours, and the nylon sieve has a mesh size of 150.

[0096] S3. After mixing the weighed and screened raw materials according to the ratio, add them to the agate ball mill jar, add the ball milling media, control the ball-to-material ratio and the ball milling speed, and ball mill under nitrogen protection to obtain the mixed raw materials; wherein, the ball-to-material ratio is 3:1, the ball milling speed is 250 r / min, and the ball milling time is 3h;

[0097] S4. Load the mixed raw materials into a crucible, place it in a tube furnace, and purge with nitrogen gas. First, purge with a first flow rate of 55 mL / min for 45 min, and then maintain a second flow rate of 25 mL / min for continuous purging.

[0098] S5. The temperature of the tube furnace is raised from room temperature to 400°C at a first heating rate of 8°C / min, held for 1.5 hours, and then raised to 700°C at a second heating rate of 40°C / min and held for 2.5 hours to obtain molten mixed raw materials.

[0099] S6. Pour the molten mixed raw materials into a graphite mold preheated to 350°C while hot, and let it cool naturally to room temperature to obtain the shaped glass.

[0100] S7. The formed glass and the mold are placed together in an annealing furnace and annealed to obtain the radiation-resistant low-expansion fluoride glass. The annealing process includes: first heating to 380°C at a rate of 8°C / min, then holding at that temperature for 3 hours, and finally cooling to 100°C at a rate of 1.5°C / min, and then taking it out and letting it cool naturally to room temperature.

[0101] Comparative Example 2

[0102] A method for preparing radiation-resistant, low-expansion fluoride glass includes the following steps:

[0103] S1. Place ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, and Na3AlF6 into crucibles respectively, place the crucibles in a vacuum drying oven, and dry to obtain the dried raw material; wherein, the molar percentage of ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, and Na3AlF6 is 53:10:10:10:5:2:3:7; the specific parameters for vacuum drying are: temperature 150℃, pressure 50Pa, and drying time 4h;

[0104] S2. Transfer the dried raw material to a mortar, grind it, and then pass it through a nylon sieve to obtain the sieved raw material; the grinding time is 1 hour, and the nylon sieve has a mesh size of 100.

[0105] S3. After mixing the weighed and screened raw materials according to the ratio, add them to the agate ball mill jar, add the ball milling media, control the ball-to-material ratio and the ball milling speed, and ball mill under the protection of a mixed gas of nitrogen and argon to obtain the mixed raw materials; wherein, the ball-to-material ratio is 3:1, the ball milling speed is 300 r / min, the ball milling time is 2h; the volume ratio of nitrogen to argon is 25:75;

[0106] S4. Load the mixed raw materials into a crucible, place it in a tube furnace, and purge with a mixture of nitrogen and argon. First, purge with a first flow rate of 60 mL / min for 30 min, and then maintain a second flow rate of 30 mL / min for continuous purging; the volume ratio of nitrogen to argon is 25:75.

[0107] S5. The temperature of the tube furnace is raised from room temperature to 400°C at a first heating rate of 10°C / min, held for 1 hour, and then raised to 700°C at a second heating rate of 50°C / min and held for 2 hours to obtain molten mixed raw materials.

[0108] S6. Pour the molten mixed raw materials into a graphite mold preheated to 400°C while hot, and let it cool naturally to room temperature to obtain the shaped glass.

[0109] S7. The formed glass and the mold are placed together in an annealing furnace and annealed to obtain the radiation-resistant low-expansion fluoride glass. The annealing process includes: first heating to 400°C at a rate of 10°C / min, then holding at that temperature for 2 hours, and finally cooling to 100°C at a rate of 2°C / min, and then taking it out and letting it cool naturally to room temperature.

[0110] Comparative Example 3

[0111] A method for preparing radiation-resistant, low-expansion fluoride glass includes the following steps:

[0112] S1. Place ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3, and Na3AlF6 into crucibles respectively, and place the crucibles in a vacuum drying oven to obtain dried raw materials. The molar percentages of ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3, and Na3AlF6 are 43:12:13:7:5:2:5:6:7. The specific parameters for vacuum drying are: temperature 125℃, pressure 25Pa, and drying time 5h.

[0113] S2. Transfer the dried raw material to a mortar, grind it, and then pass it through a nylon sieve to obtain the sieved raw material; the grinding time is 2 hours, and the nylon sieve has a mesh size of 180 mesh;

[0114] S3. After mixing the weighed and screened raw materials according to the ratio, add them to the agate ball mill jar, add the ball milling media, control the ball-to-material ratio and the ball milling speed, and ball mill under argon protection to obtain the mixed raw materials; wherein, the ball-to-material ratio is 3:1, the ball milling speed is 250 r / min, and the ball milling time is 3h;

[0115] S4. Load the mixed raw materials into a crucible, place it in a tube furnace, and purge with argon gas. First, purge with a first flow rate of 50 mL / min for 40 min, and then maintain a second flow rate of 25 mL / min for continuous purging.

[0116] S5. The temperature of the tube furnace is raised from room temperature to 400°C at a first heating rate of 5°C / min, held for 1.5 hours, and then raised to 700°C at a second heating rate of 45°C / min and held for 2 hours to obtain molten mixed raw materials.

[0117] S6. Pour the molten mixed raw materials into a stainless steel mold preheated to 360°C while hot, and let it cool naturally to room temperature to obtain fluoride glass.

[0118] The fluoride glasses prepared in Examples 1-6 and Comparative Examples 1-3 were tested for radiation resistance (8 hours of X-ray irradiation, working voltage: 100kV, working current: 7mA±0.5mA) and coefficient of thermal expansion. The radiation resistance performance was represented by the visible light transmittance of the prepared fluoride glasses after irradiation. The test results are shown in Table 1.

[0119] Table 1. Test results of fluoride glasses prepared in Examples 1-6 and Comparative Examples 1-3

[0120] Visible light transmittance after irradiation (%) Coefficient of thermal expansion ( / °C) Example 1 92 <![CDATA[6.7×10 -7 ]]> Example 2 90 <![CDATA[7.2×10 -7 ]]> Example 3 93 <![CDATA[6.4×10 -7 ]]> Example 4 91 <![CDATA[6.9×10 -7 ]]> Example 5 91 <![CDATA[7.1×10 -7 ]]> Example 6 93 <![CDATA[6.5×10 -7 ]]> Comparative Example 1 87 <![CDATA[3.7×10 -6 ]]> Comparative Example 2 79 <![CDATA[4.9×10 -7 ]]> Comparative Example 3 73 <![CDATA[5.1×10 -6 ]]>

[0121] As shown in Table 1, the radiation resistance and low expansion characteristics of Examples 1-6 are generally better than those of Comparative Examples 1-3.

[0122] The main reason is that Examples 1-6 use ZrF4 to form the framework of the fluoride glass network, where the rigid structure of the Zr-F bonds provides basic stability. Furthermore, CaF2, BaF2, and SrF2, as crystal network modifiers, introduce larger Ca atoms... 2+ Ba 2+ and Sr 2+ Ions fill the gaps in the crystal network, suppressing the crystal volume expansion caused by thermal vibrations induced by radiation. Simultaneously, the addition of LiF, NaF, AlF3, and Na3AlF6 introduces small-sized lithium, sodium, and aluminum ions, further filling the gaps in the crystal network. These ions, in conjunction with ZrF4, BaF2, and SrF2, act like adding pebbles and sand to a container already full of large rocks, promoting the densification of the crystal network in the fluoride glass and thus further reducing its coefficient of thermal expansion. Furthermore, the bonding between various metal ions and fluoride ions significantly enhances the structural rigidity of the resulting fluoride glass crystal network, thereby reducing radiation-induced structural defects and improving radiation resistance. Finally, Ce is introduced into the fluoride glass via CeF3, due to its unique 4f outer electron configuration. 1 5d 1 6s 2 Therefore, Ce can exist stably in fluoride glasses. 3+ and Ce 4+ The two valence states can interconvert by capturing free electrons and holes generated by radiation, thereby blocking the formation of crystal color centers and further improving radiation resistance. Simultaneously, by combining raw material dehydration and ball milling for homogenization, effective inert atmosphere protection during melting, the use of matching graphite or silicon carbide molds, and temperature control during annealing, the resulting fluoride glass possesses radiation resistance, low expansion, high chemical stability, and structural integrity, making it suitable for various demanding applications.

[0123] In contrast, the fluoride glass prepared in Comparative Example 1 does not contain LiF, AlF3, NaF, or Na3AlF6. Therefore, it does not introduce small-sized lithium, sodium, and aluminum ions, which cannot further fill the gaps in the crystal network and cannot interact with ZrF4, BaF2, and SrF2. Consequently, the crystal network in the fluoride glass cannot be further densified, resulting in a higher coefficient of thermal expansion. Furthermore, the absence of lithium, sodium, and aluminum ions reduces the bonding between various metal ions and fluoride ions, weakening the structural rigidity of the fluoride glass crystal network. This makes it difficult to reduce radiation-induced structural defects, thus lowering its radiation resistance.

[0124] The fluoride glass prepared in Comparative Example 2 does not contain CeF3 in its composition; therefore, the two valence states of Ce do not exist in the fluoride glass.3+ and Ce 4+ Therefore, it is difficult to block the formation of crystal color centers, resulting in fluoride glass with poor radiation resistance, but the coefficient of thermal expansion does not change much.

[0125] Comparative Example 3 uses a stainless steel mold without an annealing process. As a result, the stress in the fluoride glass produced is difficult to release in time, which easily leads to cracks, poor stability and structural integrity, poor radiation resistance, and a large coefficient of thermal expansion.

[0126] The above results demonstrate and describe the basic principles and main features of this application, as well as its advantages.

[0127] Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the equivalents of the appended claims.

Claims

1. A radiation-resistant, low-expansion fluoride glass, characterized in that, All components of the radiation-resistant, low-expansion fluoride glass are fluorine-containing compounds; the fluorine-containing compounds include: ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3 and Na3AlF6; the molar percentages of ZrF4, BaF2, SrF2, LiF, AlF3, NaF, CaF2, CeF3 and Na3AlF6 are: (40~55): (10~15): (10~15): (5~10): (5~10): (2~5): (3~5): (5~10): (5~10).

2. A method for preparing a radiation-resistant, low-expansion fluoride glass, used to prepare the radiation-resistant, low-expansion fluoride glass as described in claim 1, characterized in that, Includes the following steps: S1. Place each component of the fluorine-containing compound into a crucible, place the crucible into a vacuum drying oven, and dry to obtain the dried raw material; S2. Transfer the dried raw material to a mortar, grind it, and then pass it through a nylon sieve to obtain the sieved raw material. S3. After mixing the weighed and screened raw materials according to the proportion, add them to the agate ball mill jar, add the ball milling media, control the ball-to-material ratio and ball milling speed, and ball mill under inert gas protection to obtain the mixed raw materials. S4. Load the mixed raw materials into a crucible, place it in a tube furnace, and introduce inert gas. First, purge at the first flow rate for 30-60 minutes, and then maintain the second flow rate for continuous gas introduction. S5. Raise the temperature of the tube furnace from room temperature to 400°C at the first heating rate, hold for 1-2 hours, then continue to raise the temperature to 700°C at the second heating rate and hold for 2-3 hours to obtain molten mixed raw materials. S6. Pour the molten mixture into a preheated mold and allow it to cool naturally to room temperature to obtain the shaped glass. S7. Place the formed glass and the mold together into an annealing furnace, and after annealing, obtain the radiation-resistant, low-expansion fluoride glass.

3. The method for preparing radiation-resistant, low-expansion fluoride glass according to claim 2, characterized in that, In S1, the specific drying parameters are: temperature 120~150℃, pressure 10~50Pa, and drying time 4~6h.

4. The method for preparing radiation-resistant, low-expansion fluoride glass according to claim 2, characterized in that, In S2, the grinding time is 1~2 hours, and the nylon sieve mesh size is 100~200 mesh.

5. The method for preparing radiation-resistant, low-expansion fluoride glass according to claim 2, characterized in that, In S3, the ball-to-material ratio is 3:1, the ball milling speed is 200~300 r / min, and the ball milling time is 2~4 h.

6. The method for preparing radiation-resistant, low-expansion fluoride glass according to claim 2, characterized in that, In S3 and S4, the inert gas includes any one of nitrogen, argon, and a mixture of nitrogen and argon; in the mixture of nitrogen and argon, the volume ratio of nitrogen to argon is (20~30):(70~80).

7. The method for preparing radiation-resistant, low-expansion fluoride glass according to claim 2, characterized in that, In S4, the first flow rate is 50~60 mL / min, and the second flow rate is 20~30 mL / min.

8. The method for preparing radiation-resistant, low-expansion fluoride glass according to claim 2, characterized in that, In S5, the first heating rate is 5~10℃ / min, and the second heating rate is 30~50℃ / min.

9. The method for preparing radiation-resistant, low-expansion fluoride glass according to claim 2, characterized in that, In S6, the preheated mold includes either a graphite mold or a silicon carbide mold; the preheating temperature is 300~400℃.

10. The method for preparing radiation-resistant, low-expansion fluoride glass according to claim 2, characterized in that, In S7, the annealing process includes: First, raise the temperature to 350-400℃ at a rate of 5-10℃ / min, then keep it at that temperature for 2-4 hours. Finally, lower the temperature to 100℃ at a rate of 1-2℃ / min, and then remove it and let it cool naturally to room temperature.

Images