Low-hydroxyl quartz glass and preparation method therefor

Abstract

The present invention provides a low-hydroxyl quartz glass and a preparation method therefor. The hydroxyl content of the low-hydroxyl quartz glass is 0.1-0.95 ppm. The low-hydroxyl quartz glass provided by the present invention has relatively low hydroxyl content, and can solve the problem of high hydroxyl content in quartz glass.

Description

Low-hydroxyl quartz glass and preparation method thereof TECHNICAL FIELD

[0001] The present application belongs to the technical field of materials, and particularly relates to a low-hydroxyl quartz glass and a preparation method thereof. BACKGROUND

[0002] The content of hydroxyl in quartz has a great influence on the quality of quartz glass. The hydroxyl can strongly absorb infrared light waves of a certain wavelength, leading to problems such as cracking of the quartz glass at high temperatures. The presence of hydroxyl also reduces the mechanical properties of the glass, making it prone to breakage. Therefore, hydroxyl is the main impurity in quartz glass. With the change of the content of hydroxyl in quartz glass, the performance of the quartz glass also changes. With the increase of the content of hydroxyl, the viscosity, density and refractive index of the quartz glass decrease, and the infrared absorption and expansion coefficient increase. For key materials used in the fields of optical fibers, high-energy lasers, semiconductor integrated circuits, precision optics and instruments, and optoelectronic devices, the content of hydroxyl in the glass needs to be strictly monitored.

[0003] In the prior art, low-hydroxyl quartz glass is generally prepared by a continuous melting process or a two-step process of gas refining. However, the deposition efficiency is slow, which is not suitable for mass production. In addition, the quartz glass prepared has appearance defects such as bubbles, gas lines and hydroxyl impurities. SUMMARY

[0004] The main purpose of the present application is to provide a low-hydroxyl quartz glass with a low content of hydroxyl, which can solve the problem of high content of hydroxyl in quartz glass.

[0005] The present application also provides a preparation method of low-hydroxyl quartz glass. The preparation method is simple, easy to implement, low in cost, high in production efficiency, and suitable for mass production.

[0006] In a first aspect, the present application provides a low-hydroxyl quartz glass, wherein the content of hydroxyl in the low-hydroxyl quartz glass is 0.1-0.95 ppm.

[0007] The low-hydroxyl quartz glass as described above, wherein the content of hydroxyl in the low-hydroxyl quartz glass is 0.1-0.22 ppm.

[0008] In a second aspect, the present application provides a preparation method of the low-hydroxyl quartz glass as described above, comprising the following steps:

[0009] 1) subjecting raw materials comprising a silicon source, an inert gas, hydrogen and oxygen to deposition treatment on a carrier to obtain a silica loose body;

[0010] 2) subjecting the silica loose body to dehydration treatment at 300-600 DEG C to obtain a dehydration product;

[0011] 3) subjecting the dehydration product to a dehydroxy treatment at 850-1000℃ to obtain a dehydroxy product;

[0012] 4) subjecting the dehydroxy product to a temperature rising treatment at a temperature rising rate of 0.75-2.5℃ / min until reaching a glass transition temperature to obtain the low-hydroxyl quartz glass.

[0013] The preparation method as described above, the deposition treatment is carried out in a deposition chamber, the deposition chamber comprises a first torch and a second torch for carrying out the deposition treatment, the spraying directions of the first torch and the second torch are towards the carrier;

[0014] The included angle θ1 between the spraying direction of the first torch and the axis of the carrier is 35-45°; and / or,

[0015] The included angle θ2 between the spraying direction of the second torch and the axis of the carrier is (0.6-0.8)θ1.

[0016] The preparation method as described above, the distance h between the flame burning centers generated by the first torch and the second torch and the distance L between the burner mouths of the first torch and the second torch satisfy: h=L-20(1-sinθ1+sinθ2);

[0017] The L is 20-25cm.

[0018] The preparation method as described above, the flow rate of the inert gas in the first torch and the second torch is 10-15L / min; and / or,

[0019] The ratio of hydrogen to oxygen in the first torch and the second torch is 1.5-2:1; and / or,

[0020] The ratio of silicon to oxygen in the first torch and the second torch is 0.6-1.2:1.

[0021] The preparation method as described above, the dehydration treatment comprises: introducing He gas at a speed of 10-40L / min for 1-3h, then vacuumizing to -0.6--1.0Pa, and making the silica loose body enter a sintering furnace at a speed of 1-3mm / min, and keeping for 3-6h.

[0022] The preparation method as described above, the dehydroxy treatment comprises: introducing He gas at a speed of 10-40L / min for 1-3h, then vacuumizing to -0.6--1.0Pa, and subjecting the dehydration product to a dehydroxy treatment for 4-6h.

[0023] The preparation method as described above, the temperature rising treatment comprises: introducing He gas at a speed of 10-40L / min for 1-3h, then vacuumizing to -0.6--1.0Pa, and subjecting the dehydroxy product to a temperature rising treatment for 4-10h; and / or,

[0024] After the temperature is raised to the glass transition temperature, the method further comprises: introducing He gas at a speed of 10-40 L / min for 1-3 h, then vacuumizing to-0.6 to-1.0 Pa, and keeping at 1400-1600 ℃ for 2-4 h to obtain the low-hydroxyl quartz glass.

[0025] The preparation method as described above, the carrier is rotated along the self axis, and the rotation speed of the carrier is 5-40 r / min.

[0026] The low-hydroxyl quartz glass provided by the application has a low hydroxyl content, and can solve the problem of high hydroxyl content in quartz glass. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings needed to be used in the description of the embodiments of the present application or the related art are briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0028] Fig. 1 is a schematic diagram of the device for deposition treatment of the present application;

[0029] Fig. 2 is a schematic diagram of the device for sintering treatment of the present application;

[0030] Fig. 3 is a display diagram of each stage of sintering treatment of the present application;

[0031] Fig. 4 is the test result of the surface temperature of the silica loose body in embodiments 1-3 of the present application;

[0032] Fig. 5 is the hydroxyl content distribution diagram of the low-hydroxyl quartz glass in embodiments 1-3 of the present application;

[0033] Fig. 6 is the test result of the surface temperature of the silica loose body in embodiments 4-6 of the present application;

[0034] Fig. 7 is the hydroxyl content distribution diagram of the low-hydroxyl quartz glass in embodiments 4-6 of the present application;

[0035] Fig. 8 is the hydroxyl content distribution diagram of the quartz glass in comparative examples 1-3 of the present application;

[0036] Fig. 9 is the hydroxyl content distribution diagram of the quartz glass in comparative examples 4-6 of the present application.

[0037] Explanation of reference signs: 1-carrier; 2-silica loose body; 3-deposition cavity; 4-first fixed end; 5-flame burning center distance h generated by first torch and second torch; 6-first torch; 7-second torch; 8-lamp port distance L of first torch and second torch; 9-second fixed end; 10-sealing ring; 11-pressure gauge; 12-exhaust pipe; 13-square cavity; 14-separation plate; 15-graphite resistor; 16-sintering furnace body; 17-gas supply pipe. DETAILED DESCRIPTION

[0038] To make the objectives, technical solutions, and advantages of the present application clearer, the following will describe the technical solutions in the embodiments of the present application in a clear and complete manner with reference to the embodiments of the present application. Obviously, the described embodiments are only some, but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0039] In a first aspect, the present application provides a low-hydroxyl silica glass, wherein the hydroxyl content of the low-hydroxyl silica glass is 0.1-0.95 ppm.

[0040] It can be understood that the hydroxyl content in the silica glass will affect its bonding structure, and further affect the performance of the silica glass. Generally, low-hydroxyl silica glass is usually used for silica auxiliary materials, and is widely used in the optical fiber communication and semiconductor industries, and is also required in different fields such as special experimental equipment, aerospace, and biomedical fields, and the like. And the hydroxyl content is required to be as low as possible.

[0041] In the present application, the hydroxyl content of the low-hydroxyl silica glass is 0.1-0.95 ppm, which is in a lower range, and can solve the problem of high hydroxyl content in the silica glass.

[0042] In some embodiments of the present application, the hydroxyl content of the low-hydroxyl silica glass is 0.1-0.22 ppm.

[0043] In the present application, the hydroxyl content of the low-hydroxyl silica glass is limited to 0.1-0.22 ppm, which is a preferred solution, and can further solve the problem of high hydroxyl content in the silica glass.

[0044] In a second aspect, the present application provides a preparation method of the low-hydroxyl silica glass as described above, comprising the following steps:

[0045] 1) subjecting raw materials comprising a silicon source, an inert gas, hydrogen, and oxygen to a deposition treatment on a carrier to obtain a silica loose body;

[0046] 2) subjecting the silica bulk to a dehydration treatment at 300-600℃ to obtain a dehydrated product;

[0047] 3) subjecting the dehydrated product to a dehydroxylation treatment at 850-1000℃ to obtain a dehydroxylated product;

[0048] 4) subjecting the dehydroxylated product to a temperature rising treatment at a temperature rising rate of 0.75-2.5℃ / min until reaching a glass transition temperature to obtain the low-hydroxyl quartz glass.

[0049] In the present application, the low-hydroxyl quartz glass can be prepared by subjecting the raw material to a deposition treatment, a dehydration treatment, a dehydroxylation treatment, a temperature rising treatment and a glass transition treatment.

[0050] Specifically, in step 1), the silicon source reacts with the water vapor generated by the combustion of hydrogen and oxygen to form silica particles and deposit on the carrier to obtain a silica bulk. The carrier can be a quartz target rod; the silicon source can be selected from at least one of siloxane, alkoxide and tetrachloride containing silicon, for example, the silicon source can be selected from at least one of silicon tetrachloride, organosiloxane and polysiloxane, for example, at least one of hexamethyldisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane and hexamethylcyclotrisiloxane; the inert gas can be Ar gas. FIG. 1 is a schematic diagram of the deposition treatment device of the present application. As shown in FIG. 1, the carrier (quartz target rod) 1 can be fixed at the first fixed end 4 of the chemical vapor deposition (VAD) machine, at this time, the carrier (quartz target rod) 1 is in the deposition cavity 3, and the deposition treatment of the carrier (quartz target rod) 1 can obtain the silica bulk 2. The present application uses an axial vapor deposition process, and the silica bulk 2 is prepared by using a VAD machine, which has high deposition efficiency and is suitable for large-scale production.

[0051] In step 2), the silica bulk is subjected to a dehydration treatment at 300-600℃ to remove the physical water on the surface of the silica bulk and also remove the overflow hydroxyl to obtain a dehydrated product.

[0052] In step 3), the dehydrated product is subjected to a dehydroxylation treatment at 850-1000℃ to remove the water and decomposed hydroxyl inside the dehydrated product by high temperature to obtain a dehydroxylated product.

[0053] In step 4), the dehydroxylated product is subjected to a temperature rising treatment at a temperature rising rate of 0.75-2.5℃ / min until reaching a glass transition temperature to obtain the low-hydroxyl quartz glass. This stage is a stage for the temperature rising of the dehydroxylation treatment and the transition to the glass transition temperature. Under a suitable temperature rising rate, the residual gas inside the dehydroxylated product, for example, water vapor and decomposed hydroxyl, is further discharged by heating, so that the product structure is more compact, the internal bubbles, gas lines and hydroxyl impurities of the product are effectively removed, and the internal structure defects are repaired.

[0054] The axial vapor deposition process is used for deposition treatment in the application, and the deposition efficiency is high; through dehydration treatment, hydroxyl removal treatment, temperature increase treatment and vitrification treatment, the bubbles, gas lines and hydroxyl impurities in the silica loose body can be removed, and the loose body is simultaneously converted into a compact structure in a glass state, without using chlorine and fluorine containing hydroxyl removal agents, so that the cost is saved and the environmental benefits are achieved, and the application is suitable for large-scale mass production.

[0055] In some embodiments of the application, the deposition treatment is performed in a deposition cavity 3, the deposition cavity 3 comprising a first burner 6 and a second burner 7 for performing the deposition treatment, the spraying directions of the first burner 6 and the second burner 7 being towards the carrier;

[0056] The included angle θ1 between the spraying direction of the first burner 6 and the axis of the carrier is 35-45°; and / or,

[0057] The included angle θ2 between the spraying direction of the second burner 7 and the axis of the carrier is (0.6-0.8) θ1.

[0058] In the application, the deposition treatment is performed in a deposition cavity 3, and the deposition cavity 3 comprises a first burner 6 and a second burner 7 for performing the deposition treatment, the spraying directions of the first burner 6 and the second burner 7 being towards the carrier, and the spraying directions of the first burner 6 and the second burner 7 and the axis of the carrier have certain included angles θ1 and θ2, so that the content of hydroxyl in the quartz glass can be further reduced.

[0059] In some embodiments of the application, the flame burning center distance h generated by the first burner 6 and the second burner 7 and the burner port distance L of the first burner 6 and the second burner 7 satisfy: h = L-20(1-sin θ1+sin θ2);

[0060] Wherein, the L is 20-25 cm.

[0061] In the deposition treatment process of the application, the flame burning center distance h generated by adjusting the two burners can further reduce the content of hydroxyl in the quartz glass.

[0062] In some embodiments of the application, the flow rate of the inert gas in the first burner 6 and the second burner 7 is 10-15 L / min; and / or,

[0063] The hydrogen-oxygen ratio in the first burner 6 and the second burner 7 is 1.5-2:1; and / or,

[0064] The silicon-oxygen ratio in the first burner 6 and the second burner 7 is 0.6-1.2:1.

[0065] The flow of inert gas in the first torch 6 and the second torch 7, the hydrogen-oxygen ratio and the silicon-oxygen ratio are limited in the application, so that the gas mixture is more uniform, and the maximum silicon dioxide can be generated to be deposited on the carrier, and the content of hydroxyl in the quartz glass is further reduced.

[0066] In some embodiments of the application, the dehydration treatment comprises: introducing He gas at a speed of 10-40 L / min for 1-3 h, then vacuumizing to -0.6 to -1.0 Pa, and then making the silica loose body enter the sintering furnace at a speed of 1-3 mm / min, and keeping for 3-6 h.

[0067] In some embodiments of the application, the dehydration treatment comprises: introducing He gas at a speed of 10-40 L / min for 1-3 h, then vacuumizing to -0.6 to -1.0 Pa, and then making the silica loose body enter the sintering furnace at a speed of 1-3 mm / min, and keeping for 3-6 h.

[0068] In some embodiments of the application, the dehydroxy treatment comprises: introducing He gas at a speed of 10-40 L / min for 1-3 h, then vacuumizing to -0.6 to -1.0 Pa, and then dehydroxy treating the dehydration product for 4-6 h.

[0069] In some embodiments of the application, the dehydroxy treatment comprises: introducing He gas at a speed of 10-40 L / min for 1-3 h, then vacuumizing to -0.6 to -1.0 Pa, and then dehydroxy treating the dehydration product for 4-6 h.

[0070] In some embodiments of the application, the temperature rising treatment comprises: introducing He gas at a speed of 10-40 L / min for 1-3 h, then vacuumizing to -0.6 to -1.0 Pa, and then temperature rising treating the dehydroxy product for 4-10 h; and / or,

[0071] After rising to the glass transition temperature, it further comprises: introducing He gas at a speed of 10-40 L / min for 1-3 h, then vacuumizing to -0.6 to -1.0 Pa, and then keeping at 1400-1600 ℃ for 2-4 h to obtain the low-hydroxyl quartz glass.

[0072] The temperature rising treatment in the application specifically comprises: passing He gas at a speed of 10-40 L / min for 1-3 h, then vacuumizing to -0.6 to -1.0 Pa, and performing temperature rising treatment on the dehydroxy product for 4-10 h, which can further discharge the residual gas in the dehydroxy product, avoid the generation of bright spots, and reduce the content of hydroxyl in the product.

[0073] The vitrification treatment in the application specifically comprises: passing He gas at a speed of 10-40 L / min for 1-3 h, then vacuumizing to -0.6 to -1.0 Pa, and keeping at 1400-1600 ℃ for 2-4 h, which can gradually convert the loose body into a glass state, promote the structural relaxation of quartz glass, and further homogenize the internal glass state.

[0074] In some embodiments of the application, the carrier rotates along its own axis, and the rotation speed of the carrier is 5-40 r / min.

[0075] The carrier in the application can rotate along its own axis, and the rotation speed is 5-40 r / min, which is in a suitable range, can make the silica deposited on the carrier more uniform, and is beneficial to reducing the content of hydroxyl in the final quartz glass.

[0076] The technical solutions of the application are further described below in combination with specific examples.

[0077] The preparation of the low-hydroxyl quartz glass in the example is carried out by using the devices in FIG. 1 and FIG. 2, wherein FIG. 1 is a schematic diagram of a deposition treatment device in the application; and FIG. 2 is a schematic diagram of a dehydration treatment, dehydroxy treatment, temperature rising treatment and vitrification treatment device in the application.

[0078] Example 1

[0079] The preparation method of the low-hydroxyl quartz glass in the example comprises the following steps:

[0080] 1) The deposition is carried out by using a chemical vapor deposition (VAD) process, first, a carrier (quartz target rod) 1 is fixed at a first fixed end 4 of a VAD machine table, and the rotation speed of the carrier is set to 25 r / min, at this time, the included angle θ1 between the jet direction of the first torch 6 and the axis of the carrier is 45°, and the included angle θ2 between the jet direction of the second torch 7 and the axis of the carrier is 36°. The mixed gas of raw material SICl4, H2, O2 and Ar gas is passed into the first torch 6 and the second torch 7, and the flow rates are 48 L / min, 60 L / min, 40 L / min and 10 L / min respectively, and ignition operation is performed. At the same time, the jet directions of the first torch 6 and the second torch 7 are towards the carrier, the center distance h between the torch flame burning centers generated by the first torch 6 and the second torch 7 is 7.38 cm, and the distance L from the lamp port of the first torch 6 to the lamp port of the second torch 7 is 25 cm. After waiting for the deposition to be completed, the silica loose body 2 is obtained.

[0081] 2) The silica loose body is fixed by the second fixed end 9, and is lowered into the square cavity 13. The sealing ring 10 is installed and fixed. The temperature in the cavity is normal room temperature. Before sintering, the partition plate 14 is removed, and the silica loose body 2 is lowered into the VSI sintering furnace. The He gas with a flow rate of 30 L / min is introduced through the gas pipeline 17, and the rod lowering speed is 1 mm / min. The gas exchange and pressure adjustment are performed through the exhaust pipeline 12, and the vacuum degree in the sintering furnace is adjusted to -0.6 Pa. The graphite resistance 15 starts to heat, and the He gas with a flow rate of 20 L / min is introduced. At this time, the temperature in the cavity is heated to 600 DEG C, and the dehydration treatment is performed under the constant temperature condition for 3 h. The He gas with a flow rate of 30 L / min is introduced for 2 h, and then the temperature is increased to the dehydroxy temperature of 950 DEG C, and enters the dehydroxy stage. The quartz target rod is suspended in the center of the sintering furnace, and the duration is 4 h. After the dehydroxy ends, it enters the temperature rising stage, and the temperature rising rate is 0.75 DEG C / min. This stage is the dehydroxy temperature rising and the transition to the glassification temperature. The quartz target rod is suspended in the center of the furnace. The He gas with a flow rate of 20 L / min is introduced for 1 h, and then the vacuum is extracted. The vacuum degree in the sintering furnace is controlled to -0.6 Pa. Under the high-temperature negative pressure, the residual gas in the interior is further discharged from the rod body (the time is 10 h). The structure of the powder particles is more compact, and the bubbles are gradually discharged from the rod body. In the glassification stage, the temperature is 1400 DEG C, and the quartz target rod is suspended in the center of the furnace. The He gas with a flow rate of 30 L / min is introduced for 2 h, and then the vacuum is extracted. The vacuum degree in the sintering furnace is controlled to -0.6 Pa. The glassification stage is 4 h, and the low-hydroxyl quartz glass is obtained.

[0082] Example 2-3

[0083] The preparation method of the low-hydroxyl quartz glass in Example 2-3 is basically the same as that in Example 1, except that the included angle θ1 between the jet direction of the first torch 6 and the axis of the carrier and the included angle θ2 between the jet direction of the second torch 7 and the axis of the carrier are changed. The results are shown in Table 1.

[0084] The temperatures at the points 1 to 5 measured every 3 cm upward from the lower edge of the flame of the first torch 6 are shown in Table 1. Each point in the table represents the average temperature of the corresponding point of the intact rod.

[0085] Table 1

[0086] The hydroxyl content of Example 1 is respectively: 0.117 ppm, 0.109 ppm, 0.113 ppm, 0.136 ppm, 0.129 ppm, 0.111 ppm, and 0.121 ppm.

[0087] The hydroxyl contents of Examples 2 are respectively: 0.167 ppm, 0.141 ppm, 0.154 ppm, 0.179 ppm, 0.176 ppm, 0.159 ppm, 0.163 ppm.

[0088] The hydroxyl contents of Examples 3 are respectively: 0.201 ppm, 0.172 ppm, 0.177 ppm, 0.216 ppm, 0.214 ppm, 0.19 ppm, 0.194 ppm.

[0089] The flame burning center distance h generated by the first torch 6 and the second torch 7, the angle θ1 between the first torch 6 and the axis of the carrier, and the angle θ2 between the second torch 7 and the axis of the carrier are suitable, and the silica loose body 2 is successfully formed; the angles θ1 between the first torch 6 and the axis of the carrier and the angles θ2 between the second torch 7 and the axis of the carrier of Examples 2-3 are all reduced, so that the flame burning center distance h generated by the first torch 6 and the second torch 7 is reduced, the temperature at the intersection of the flames is increased, and the hydroxyl content of the obtained silica loose body 2 is increased.

[0090] Example 4

[0091] The method for preparing the low-hydroxyl quartz glass of the present embodiment comprises the following steps:

[0092] 1) Using the chemical vapor deposition (VAD) process for deposition, first fix a carrier (quartz target rod) 1 at the first fixed end 4 of the VAD machine, click the carrier rotation to set the rotation speed to 25 r / min, at this time the angle θ1 between the spraying direction of the first torch 6 and the axis of the carrier is 45°, and the angle θ2 between the spraying direction of the second torch 7 and the axis of the carrier is 36°. The mixed gas of raw materials SICl4, H2, O2 and Ar gas is introduced into the first torch 6 and the second torch 7, and the flow rates are respectively 24 L / min, 60 L / min, 40 L / min and 15 L / min, and ignition operation is performed. At the same time, the spraying directions of the first torch 6 and the second torch 7 are towards the carrier, the torch flame burning center distance h generated by the first torch 6 and the second torch 7 is 7.38 cm, and the distance L from the lamp port of the first torch 6 to the lamp port of the second torch 7 is 25 cm. Wait for the deposition to be completed, and obtain the silica loose body 2.

[0093] 2) The silica loose body is fixed by the second fixed end 9, and is lowered into the square cavity 13. The sealing ring 10 is installed and fixed. The temperature in the cavity is normal room temperature. Before sintering, the partition plate 14 is removed, and the silica loose body 2 is lowered into the VSI sintering furnace. The He gas with a flow rate of 30 L / min is introduced through the gas pipeline 17, and the rod lowering speed is 3 mm / min. The gas exchange and pressure adjustment are performed through the exhaust pipeline 12, and the vacuum degree in the sintering furnace is adjusted to -0.8 Pa. The graphite resistance 15 starts to heat, and the He gas with a flow rate of 20 L / min is introduced. At this time, the temperature in the cavity is heated to 500 DEG C, and the dehydration treatment is performed under the constant temperature condition for 3 h. The He gas with a flow rate of 30 L / min is introduced for 2 h, and then the temperature is increased to the dehydroxy temperature of 950 DEG C, and enters the dehydroxy stage. The quartz target rod is suspended in the center of the sintering furnace, and the duration is 4 h. After the dehydroxy ends, it enters the temperature rising stage, and the temperature rising rate is 0.917 DEG C / min. This stage is the dehydroxy temperature rising and the transition to the glassification temperature. The quartz target rod is suspended in the center of the furnace. The He gas with a flow rate of 20 L / min is introduced for 1 h, and then the vacuum is extracted. The vacuum degree in the sintering furnace is controlled to -0.8 Pa. Under the high-temperature negative pressure, the residual gas in the rod body is further discharged (the time is 10 h). The structure of the powder particles is more compact, and the bubbles are gradually discharged from the rod body. In the glassification stage, the temperature is 1500 DEG C, and the quartz target rod is suspended in the center of the furnace. The He gas with a flow rate of 35 L / min is introduced for 2 h, and then the vacuum is extracted. The vacuum degree in the sintering furnace is controlled to -0.8 Pa. The glassification stage is 3 h, and the low-hydroxyl quartz glass is obtained.

[0094] Examples 5-6

[0095] Examples 5-6 and the preparation method of the low-hydroxyl quartz glass of Example 1 are basically the same, except that the distance L between the lamp mouths of the first torch 6 and the second torch 7 is changed. The results are shown in Table 2.

[0096] The temperatures at the points 1 to 5, which are measured every 3 cm upward from the lower edge of the flame of the first torch 6, are shown in Table 2. Each point in the table represents the average temperature of the corresponding point of the intact rod.

[0097] Table 2

[0098] The hydroxyl contents of Example 4 are respectively: 0.134 ppm, 0.169 ppm, 0.187 ppm, 0.122 ppm, 0.153 ppm, 0.186 ppm, and 0.131 ppm.

[0099] The hydroxyl contents of Example 5 are respectively: 0.496 ppm, 0.515 ppm, 0.489 ppm, 0.415 ppm, 0.507 ppm, 0.482 ppm, and 0.494 ppm.

[0100] The hydroxyl contents are 0.839 ppm, 0.835 ppm, 0.847 ppm, 0.879 ppm, 0.927 ppm, 0.822 ppm, and 0.869 ppm, respectively.

[0101] The distance L between the lamp mouths of the first torch 6 and the second torch 7 in Example 4 is appropriate, and the silica loose body 2 is successfully formed. The distance L between the lamp mouths of the first torch 6 and the second torch 7 in Examples 5-6 is reduced, and thus the flame burning center distance h generated by the first torch 6 and the second torch 7 is reduced. The temperature at the flame intersection is increased, the hydroxyl content of the obtained silica loose body 2 is increased, and if the flame fluctuates, the temperature at the convergence point may exceed 1200°C, and hardened spots may be formed. However, the powder rod formed at such a temperature has an excellent appearance and few bubble lines.

[0102] Example 7

[0103] The method for preparing the low-hydroxyl quartz glass in this example includes the following steps:

[0104] 1) Using a chemical vapor deposition (VAD) process for deposition, first fix a carrier (quartz target rod) 1 at the first fixed end 4 of the VAD machine, click the carrier rotation to set the rotation speed to 25 r / min. At this time, the angle θ1 between the spraying direction of the first torch 6 and the axis of the carrier is 45°, and the angle θ2 between the spraying direction of the second torch 7 and the axis of the carrier is 36°. The mixed gas of raw materials SICl4, H2, O2, and Ar gas is introduced into the first torch 6 and the second torch 7, and the flow rates are 24 L / min, 80 L / min, 40 L / min, and 12 L / min, respectively, and ignition operation is performed. At the same time, the spraying directions of the first torch 6 and the second torch 7 are directed towards the carrier, the flame burning center distance h generated by the first torch 6 and the second torch 7 is 7.38 cm, and the distance L between the lamp mouth of the first torch 6 and the lamp mouth of the second torch 7 is 25 cm. Wait for the deposition to be completed, and obtain the silica loose body 2.

[0105] 2) The silica loose body is fixed by the second fixed end 9, and is lowered into the square cavity 13. The sealing ring 10 is installed and fixed. The temperature in the cavity is normal room temperature. Before sintering, the partition plate 14 is removed, and the silica loose body 2 is lowered into the VSI sintering furnace. The He gas with a flow rate of 30 L / min is introduced through the gas pipeline 17, and the rod lowering speed is 2 mm / min. The gas exchange and pressure adjustment are performed through the exhaust pipeline 12, and the vacuum degree in the sintering furnace is adjusted to -1.0 Pa. The graphite resistance 15 starts to heat, and the He gas with a flow rate of 20 L / min is introduced. At this time, the temperature in the cavity is heated to 300℃, and the dehydration treatment is performed under the constant temperature condition for 3 h. The He gas with a flow rate of 30 L / min is introduced for 2 h, and then the temperature is increased to the dehydroxy temperature of 950℃, and enters the dehydroxy stage. The quartz target rod is suspended in the center of the sintering furnace, and the duration is 4 h. After the dehydroxy ends, it enters the temperature rising stage, and the temperature rising rate is 0.75℃ / min. This stage is the dehydroxy temperature rising and the transition to the glassification temperature. The quartz target rod is suspended in the center of the furnace. The He gas with a flow rate of 20 L / min is introduced for 1 h, and then the vacuum is extracted. The vacuum degree in the sintering furnace is controlled to -1.0 Pa. Under the high-temperature negative pressure, the residual gas in the rod body is further discharged (the time is 4 h). The structure of the powder particles is more compact, and the bubbles are gradually discharged from the rod body. In the glassification stage, the temperature is 1550℃, and the quartz target rod is suspended in the center of the furnace. The He gas with a flow rate of 40 L / min is introduced for 2 h, and then the vacuum is extracted. The vacuum degree in the sintering furnace is controlled to -1.0 Pa. The glassification stage is 2 h, and the low-hydroxyl quartz glass is obtained.

[0106] Examples 8-9

[0107] Examples 8-9 and the preparation method of the low-hydroxyl quartz glass in Example 1 are basically the same, except that the temperature rising rate of the temperature rising treatment is changed. The results are shown in Table 3.

[0108] Points 1 to 7 are determined from the quartz target rod upper part downward every 200 mm.

[0109] Table 3

[0110] From Table 3, it can be seen that the hydroxyl content slightly decreases with the decrease of the temperature rising rate, but the appearance of the obtained rod is further improved. It can be known that the slower the temperature increases, the fewer the appearance defects for the deposited appearance, but when the temperature rising rate is lower than 0.75℃ / min, the time cost is too high, and the marginal benefit appears, and the improvement effect is less obvious.

[0111] Examples 10-11

[0112] Examples 10-11 and the preparation method of the low-hydroxyl quartz glass in Example 1 are basically the same, except that the rotation speed of the carrier is changed. The results are shown in Table 4.

[0113] Table 4

[0114] From Table 4, it can be seen that the hydroxyl content slightly decreases with the increase of the carrier rotation speed. Slow carrier rotation is prone to cause uneven distribution of powder, thus increasing the bright line defect. Fast carrier rotation will affect the deposition rate, so it is limited to 5-40 r / min.

[0115] Examples 12-13

[0116] Examples 12-13 and the preparation method of the low-hydroxyl quartz glass of Example 1 are basically the same, except that the lowering rod speed in the dehydration treatment is changed, and the results are shown in Table 5.

[0117] Table 5

[0118] From Table 5, it can be seen that the hydroxyl content slightly increases with the increase of the lowering rod speed in the dehydration treatment. The essence is that the increase of the lowering rod speed reduces the overall time for removing the hydroxyl impurities, thus increasing the hydroxyl content. However, the subsequent dehydroxy treatment will reduce the difference caused by this point, and finally the increase of the hydroxyl content is not obvious.

[0119] Comparative Example 1

[0120] The preparation method of the quartz glass of the present comparative example comprises the following steps:

[0121] 1) depositing by using a chemical vapor deposition (VAD) process, first fixing a carrier (quartz target rod) 1 at a first fixed end 4 of a VAD machine, setting the rotation speed to 25 r / min by clicking the carrier rotation, at this time the angle θ1 between the jet direction of the first torch 6 and the axis of the carrier is 45°, and the angle θ2 between the jet direction of the second torch 7 and the axis of the carrier is 36°. The mixed gas of raw materials SICl4, H2, O2 and Ar gas is introduced into the first torch 6 and the second torch 7, and the flow rates are 24 L / min, 60 L / min, 40 L / min and 15 L / min respectively, and ignition operation is performed. At the same time, the jet directions of the first torch 6 and the second torch 7 are directed towards the carrier, the center distance h between the torch flame burning centers generated by the first torch 6 and the second torch 7 is 7.38 cm, and the distance L from the first torch 6 to the second torch 7 is 25 cm. After waiting for the deposition to be completed, a silica loose body 2 is obtained.

[0122] 2) The silica loose body is fixed by the second fixed end 9, and is lowered into the square cavity 13. The sealing ring 10 is installed and fixed. The temperature in the cavity is normal room temperature. Before sintering, the partition plate 14 is removed, and the silica loose body 2 is lowered into the VSI sintering furnace. The He gas with a flow rate of 30 L / min is introduced through the gas pipeline 17, and the rod lowering speed is 2 mm / min. The gas exchange and pressure adjustment are performed through the exhaust pipeline 12, and the vacuum degree in the sintering furnace is adjusted to -0.6 Pa. The graphite resistance 15 starts to heat, and the He gas with a flow rate of 20 L / min is introduced. At this time, the cavity is heated to 600 DEG C, and the dehydration treatment is performed under the constant temperature condition for 3 h. The He gas with a flow rate of 30 L / min is introduced for 2 h, and then the temperature is increased to the dehydroxy temperature of 950 DEG C. The quartz target rod is suspended in the center of the sintering furnace, and the dehydroxy stage is entered. The dehydroxy stage is ended, and the temperature rising stage is entered. The temperature rising rate is 3.75 DEG C / min. In this stage, the dehydroxy temperature is increased, and the glass transition temperature is transitioned. The quartz target rod is suspended in the center of the furnace. The He gas with a flow rate of 20 L / min is introduced for 1 h, and then the vacuum is pumped. The vacuum degree in the sintering furnace is controlled to -0.6 Pa. Under the high-temperature negative pressure, the residual gas in the rod body is further discharged (the time is 2 h). The structure of the powder particles is more compact, and the bubbles are gradually discharged from the rod body. In the glassification stage, the temperature is 1400 DEG C, and the quartz target rod is suspended in the center of the furnace. The He gas with a flow rate of 30 L / min is introduced for 2 h, and then the vacuum is pumped. The vacuum degree in the sintering furnace is controlled to -0.6 Pa. The glassification stage is 4 h, and the quartz glass is obtained.

[0123] Comparative Example 2-3

[0124] The preparation method of the low-hydroxyl quartz glass in Comparative Example 2-3 is basically the same as that in Comparative Example 1, except that the temperature rising rate of the temperature rising treatment is changed. The results are shown in Table 6.

[0125] Points 1 to 7 are determined at every 200 mm from the upper part of the quartz target rod.

[0126] Table 6

[0127] The temperature rising rate of Comparative Example 1-3 is not in the range of 0.75-2.5 DEG C / min. The hydroxyl content is significantly increased, and the appearance bubbles are increased. In Comparative Example 1-3, because the temperature rising rate of the temperature rising treatment stage is fast, too many bubbles and gas lines appear in the rod, and the rod cannot be used.

[0128] Comparative Example 4

[0129] The preparation method of the quartz glass in the present comparative example includes the following steps:

[0130] 1) Using the chemical vapor deposition (VAD) process for deposition, first fix a carrier (quartz target rod) 1 at the first fixed end 4 of the VAD machine, click the carrier rotation to set the rotation speed to 25 r / min, at this time the angle θ1 between the jet direction of the first torch 6 and the axis of the carrier is 45°, and the angle θ2 between the jet direction of the second torch 7 and the axis of the carrier is 36°. The mixed gas of raw materials SICl4, H2, O2 and Ar gas is introduced into the first torch 6 and the second torch 7, and the flow rates are 48 L / min, 60 L / min, 40 L / min and 10 L / min, respectively, and ignition operation is performed. At the same time, the jet directions of the first torch 6 and the second torch 7 are directed towards the carrier, the center distance h between the torch flame burning centers generated by the first torch 6 and the second torch 7 is 7.38 cm, and the distance L from the lamp port of the first torch 6 to the lamp port of the second torch 7 is 25 cm. Wait for the deposition to be completed to obtain a silica loose body 2.

[0131] 2) The silica loose body is fixed through the second fixed end 9, lowered into the square cavity 13, and the sealing ring 10 is installed and fixed, and the temperature in the cavity is normal room temperature environment. Before sintering, remove the spacer plate 14, and lower the silica loose body 2 into the VSI sintering furnace. The temperature is raised to the dehydroxylation temperature of 950℃, and the dehydroxylation stage is entered, and the quartz target rod is suspended in the center of the sintering furnace for 4 h; after the dehydroxylation is completed, the temperature rising stage is entered, and the temperature rising rate is 2.5℃ / min, and this stage is the dehydroxylation temperature rising and the transition to the glass transition temperature, and the quartz target rod is suspended in the center area of the furnace. Introduce He 20 L / min for 1 h, and then vacuumize, and the vacuum degree in the sintering furnace is controlled to -0.6 pa. Under high temperature and negative pressure, the residual gas in the inside is further discharged from the rod body (the time is 2 h), the structure of the powder particles is more compact, and the bubbles are gradually discharged from the rod body. In the glassification stage, the temperature is 1500℃, and the quartz target rod is suspended in the center of the furnace. Introduce He 30 L / min for 2 h, and then vacuumize, and the vacuum degree in the sintering furnace is controlled to -0.8 pa, and the glassification stage is 2 h, and the quartz glass is obtained.

[0132] Comparative Example 5

[0133] The preparation method of the quartz glass of the present comparative example comprises the following steps:

[0134] 1) Using the chemical vapor deposition (VAD) process for deposition, first fix a carrier (quartz target rod) 1 at the first fixed end 4 of the VAD machine, click the carrier rotation to set the rotation speed to 25 r / min, at this time the angle θ1 between the jet direction of the first torch 6 and the axis of the carrier is 45°, and the angle θ2 between the jet direction of the second torch 7 and the axis of the carrier is 36°. The mixed gas of raw materials SICl4, H2, O2 and Ar gas is introduced into the first torch 6 and the second torch 7, and the flow rates are 48 L / min, 60 L / min, 40 L / min and 10 L / min, respectively, and ignition operation is performed. At the same time, the jet directions of the first torch 6 and the second torch 7 are directed towards the carrier, the center distance h between the torch flame burning centers generated by the first torch 6 and the second torch 7 is 7.38 cm, and the distance L from the lamp port of the first torch 6 to the lamp port of the second torch 7 is 25 cm. Wait for the deposition to be completed to obtain a silica loose body 2.

[0135] 2) The silica loose body 2 is fixed through the second fixed end 9 and lowered into the square cavity 13, and the sealing ring 10 is installed and fixed, and the temperature in the cavity is normal room temperature environment. Before sintering, remove the spacing plate 14, and lower the silica loose body 2 into the VSI sintering furnace. The temperature is raised to the dehydroxylation temperature of 950℃, and the dehydroxylation stage is entered, and the quartz target rod is suspended in the center of the sintering furnace for 4h; within 30min after the dehydroxylation is completed, the glass transition temperature is quickly raised, the heating rate is 7.5℃ / min, and the quartz target rod is suspended in the center of the furnace. Introduce He 20 L / min for 1h, then vacuumize, and control the vacuum degree in the sintering furnace to -0.6pa. Under high temperature and negative pressure, the residual gas in the inside is further discharged from the rod body (the time is 2h), the structure of the powder particles is more compact, and the bubbles are gradually discharged from the rod body. In the glass transition stage, the temperature is 1500℃, and the quartz target rod is suspended in the center of the furnace. Introduce He 30 L / min for 2h, then vacuumize, and control the vacuum degree in the sintering furnace to -0.6pa, and the glass transition stage is 3h, to obtain a quartz glass.

[0136] Comparative Example 6

[0137] The preparation method of the quartz glass of the present comparative example comprises the following steps:

[0138] 1) using chemical vapor deposition (VAD) process for deposition, first fix a carrier (quartz target rod) 1 at the first fixed end 4 of the VAD machine, click the carrier rotation to set the rotation speed to 25 r / min, at this time the angle θ1 between the spray direction of the first torch 6 and the axis of the carrier is 45°, the angle θ2 between the spray direction of the second torch 7 and the axis of the carrier is 36°. The mixed gas of raw material SICl4, H2, O2 and Ar gas is introduced into the first torch 6 and the second torch 7, the flow rates are 48 L / min, 60 L / min, 40 L / min and 10 L / min respectively, and ignition operation is performed. At the same time, the spray directions of the first torch 6 and the second torch 7 are towards the carrier, the center distance h between the torch flame burning centers generated by the first torch 6 and the second torch 7 is 7.38 cm, and the distance L from the lamp port of the first torch 6 to the lamp port of the second torch 7 is 25 cm. Wait for the deposition to be completed to obtain a silica loose body 2.

[0139] 2) The silica loose body is fixed through the second fixed end 9, is lowered into the square cavity 13, the sealing ring 10 is installed and fixed, and the temperature in the cavity is normal room temperature environment. Before sintering, the spacing plate 14 is removed, and the silica loose body 2 is lowered into the VSI sintering furnace. The temperature is raised to the dehydroxylation temperature 950℃, the dehydroxylation stage is entered, the quartz target rod is suspended in the center of the sintering furnace, and the suspension lasts for 4 h; 30 min after the dehydroxylation is completed, the glass transition temperature is rapidly raised, the heating rate is 7.5℃ / min, and the quartz target rod is suspended in the center area of the furnace. He 20 L / min is introduced for 1 h, then vacuum is pumped, and the vacuum degree in the sintering furnace is controlled to fluctuate within the range of 0-0.2 pa. Under high temperature and negative pressure, the residual gas in the rod body is further discharged (the time is 2 h), the structure of the powder particles is more compact, and the bubbles are gradually discharged from the rod body. In the glass transition stage, the temperature is 1400℃, and the quartz target rod is suspended in the center of the furnace. He 30 L / min is introduced for 2 h, then vacuum is pumped, and the vacuum degree in the sintering furnace is controlled to fluctuate within the range of 0-0.2 pa. The glass transition stage lasts for 4 h, and quartz glass is obtained.

[0140] Table 7

[0141] The comparative example 4 is not subjected to the dehydration treatment, the comparative example 5 is not subjected to the dehydration treatment and the heating rate is not within the range of 0.75-2.5℃ / min, and the comparative example 6 is not subjected to the dehydration treatment, the heating rate is not within the range of 0.75-2.5℃ / min, the dehydroxylation treatment and the glass transition treatment pressure are not within the range of -0.6~-1.0 Pa, the water content and the hydroxyl content in the powder rod cannot be effectively removed, and the hydroxyl content of the finished product is obviously increased.

[0142] Fig. 4 is a test result of the surface temperature of the silica loose body in the embodiment 1-3 of the present application;

[0143] As can be seen from Fig. 4, the surface temperature of the silica loose body in Examples 1-3 changes little.

[0144] Fig. 5 is a diagram showing the distribution of the hydroxyl content of the low-hydroxyl quartz glass in Examples 1-3 of the present application.

[0145] As can be seen from Fig. 5, the hydroxyl content of the low-hydroxyl quartz glass in Examples 1-3 is low and the distribution range is narrow.

[0146] Fig. 6 is a diagram showing the test results of the surface temperature of the silica loose body in Examples 4-6 of the present application.

[0147] As can be seen from Fig. 6, the surface temperature of the silica loose body in Examples 4-6 changes little.

[0148] Fig. 7 is a diagram showing the distribution of the hydroxyl content of the low-hydroxyl quartz glass in Examples 4-6 of the present application.

[0149] As can be seen from Fig. 7, the hydroxyl content of the low-hydroxyl quartz glass in Examples 4-6 is low and the distribution range is narrow.

[0150] Fig. 8 is a diagram showing the distribution of the hydroxyl content of the quartz glass in Comparative Examples 1-3 of the present application.

[0151] As can be seen from Fig. 8, the hydroxyl content of the quartz glass in Comparative Examples 1-3 is high and the distribution range is wide.

[0152] Fig. 9 is a diagram showing the distribution of the hydroxyl content of the quartz glass in Comparative Examples 4-6 of the present application.

[0153] As can be seen from Fig. 9, the hydroxyl content of the quartz glass in Comparative Examples 4-6 is high and the distribution range is wide.

[0154] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the same; although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that they can still modify the technical solutions described in the above examples, or make equivalent replacements to some or all of the technical features; and such modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A low-hydroxyl quartz glass, characterized in that, The hydroxyl content of the low-hydroxyl quartz glass is 0.07-0.95 ppm.

2. The low-hydroxyl quartz glass according to claim 1, characterized in that, The hydroxyl content of the low-hydroxyl quartz glass is 0.07-0.22 ppm.

3. A method for preparing low-hydroxyl quartz glass as described in claim 1 or 2, characterized in that, Includes the following steps: 1) A raw material including silicon source, inert gas, hydrogen and oxygen is deposited on a carrier to obtain a porous silica body; 2) The silica porous body is dehydrated at 300-600℃ to obtain a dehydrated product; 3) The dehydrated product is subjected to dehydroxylation treatment at 850-1000℃ to obtain the dehydroxylated product; 4) The dehydroxylated product is heated at a heating rate of 0.75-2.5℃ / min until the glass transition temperature is reached to obtain the low-hydroxyl quartz glass.

4. The preparation method according to claim 3, characterized in that, The deposition process is carried out in a deposition chamber, which includes a first torch and a second torch for performing the deposition process, with the spraying direction of the first torch and the second torch facing the carrier. The angle θ1 between the spray direction of the first blowtorch and the axis of the carrier is 35-45°; and / or, The angle θ2 between the spray direction of the second blowtorch and the axis of the carrier is (0.6-0.8)θ1.

5. The preparation method according to claim 4, characterized in that, The distance h between the flame burning centers of the first and second blowtorches and the distance L between the nozzles of the first and second blowtorches satisfy: h = L - 20(1 - sinθ1 + sinθ2); Wherein, L is 20-25cm.

6. The preparation method according to claim 4 or 5, characterized in that, The flow rate of the inert gas in the first and second blowtorches is 10-15 L / min; and / or, The hydrogen-to-oxygen ratio in the first and second blowtorches is 1.5-2:1; and / or, The silicon-to-oxygen ratio in the first and second blowtorches is 0.6-1.2:

1.

7. The preparation method according to any one of claims 3-6, characterized in that, The dehydration process includes: introducing He gas at a rate of 10-40 L / min for 1-3 hours, then evacuating to -0.6 to -1.0 Pa, so that the silica loose material enters the sintering furnace at a rate of 1-3 mm / min and is maintained for 3-6 hours.

8. The preparation method according to any one of claims 3-7, characterized in that, The dehydroxylation treatment includes: introducing He gas at a rate of 10-40 L / min for 1-3 h, then evacuating to -0.6 to -1.0 Pa, and performing dehydroxylation treatment on the dehydrated product for 4-6 h.

9. The preparation method according to any one of claims 3-8, characterized in that, The heating treatment includes: introducing He gas at a rate of 10-40 L / min for 1-3 h, then evacuating to -0.6 to -1.0 Pa, and heating the dehydroxylated product for 4-10 h; and / or, After heating to the glass transition temperature, the process further includes: introducing He gas at a rate of 10-40 L / min for 1-3 h, then evacuating to -0.6 to -1.0 Pa and maintaining at 1400-1600 °C for 2-4 h to obtain the low-hydroxyl quartz glass.

10. The preparation method according to any one of claims 3-9, characterized in that, The carrier rotates along its own axis at a speed of 5-40 r / min.

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