CN113754259B - Heat treatment method for optimizing uniformity of synthetic quartz glass - Google Patents
Heat treatment method for optimizing uniformity of synthetic quartz glass Download PDFInfo
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- CN113754259B CN113754259B CN202111182107.9A CN202111182107A CN113754259B CN 113754259 B CN113754259 B CN 113754259B CN 202111182107 A CN202111182107 A CN 202111182107A CN 113754259 B CN113754259 B CN 113754259B
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B25/00—Annealing glass products
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2201/00—Type of glass produced
- C03B2201/02—Pure silica glass, e.g. pure fused quartz
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
- Y02P40/57—Improving the yield, e-g- reduction of reject rates
Abstract
The invention relates to a heat treatment method for optimizing uniformity of synthetic quartz glass, and belongs to the technical field of quartz preparation. The heat treatment method provided by the invention is characterized in that the stress in the prepared quartz glass is completely eliminated through the pre-baking, the first-stage heat treatment, the cooling, the second-stage heat treatment, the cooling and the cooling processes, the quartz glass is uniformly diffused, and the material is prevented from deforming. The heat treatment method reduces impurity pollution and energy consumption.
Description
Technical Field
The invention relates to the technical field of quartz preparation, in particular to a heat treatment method for optimizing uniformity of synthetic quartz glass.
Background
The synthetic quartz has higher purity, can be widely applied to the fields of optics, optical communication and the like, wherein the optical field uses more synthetic quartz, but the synthetic quartz made by different processes acts on different scenes, such as the use scenes of aerospace, semiconductors, photoelectric devices, other high-end precise instruments and the like. Synthetic quartz is the most intuitively judged non-conforming item for optical products except bubble and impurity defects, but the optical uniformity of the product is a key condition for directly determining whether the product can be used or not. High temperature homogenization is a key factor in solving the optical uniformity and effectively improves the material endoplasmic homogenization.
The quartz glass homogenizing mode has slot deposition and precise annealing, wherein the precise annealing consists of three stages of heating, heat preservation and cooling, the stress of products such as conventional welding fire polishing belongs to transient stress, and the common annealing conditions can be satisfied and the stress can be completely removed. But the stress caused by the production of synthetic quartz is difficult to remove under ordinary annealing conditions and seriously affects the optical uniformity. The annealing conditions of the existing synthetic quartz ignore two problems: firstly, the synthetic quartz is polluted by the environment in the furnace, and under the condition of long-time high-temperature heat preservation, the quartz glass is easy to be polluted, and the purity of the product is influenced; secondly, the specification and the size of the synthetic quartz are larger, and the simple annealing treatment is insufficient to thoroughly solve the annealing of the large-size quartz.
Disclosure of Invention
Therefore, the invention aims to solve the technical problem of the uniformity treatment of the large-size synthetic quartz and solve the problems of environmental pollution caused by heat treatment in the prior art.
In order to solve the technical problems, the invention provides a heat treatment method for optimizing the uniformity of synthetic quartz glass.
It is a first object of the present invention to provide a heat treatment method of high-uniformity quartz glass, comprising the steps of,
s1, carrying out vacuumizing treatment while pre-baking silicon dioxide, stopping vacuumizing before the first-stage heat treatment, supplementing nitrogen to ensure slight positive pressure of gas in a furnace, and then heating to realize the first-stage heat treatment; the temperature rise is divided into two temperature rises, namely a primary temperature rise and a secondary temperature rise; the secondary temperature rise is to raise the temperature to 1100-1180 ℃ at the speed of 5-7 ℃/min, and then preserving the heat for 4-12h;
s2, cooling after the first-stage heat treatment in the step S1, and heating to realize the second-stage heat treatment; the temperature rise is divided into two temperature rises, namely a primary temperature rise and a secondary temperature rise; the temperature is reduced to 800-950 ℃ at a speed of 1-2 ℃/min, and then the temperature is kept for 3-12h; the secondary temperature rise is to raise the temperature to 1100-1180 ℃ at the speed of 0.2-0.5 ℃/min, and then preserving the heat for 6-24 hours;
and S3, cooling, annealing and cooling after the second-stage heat treatment in the step S2 to obtain the high-uniformity quartz glass.
Further, in the step S1, the vacuum degree of the vacuuming treatment reaches 4×10 -4 -7×10 -4 Pa, removing impurities and oxygen in the furnace, repeatedly circulating for 3-5 times, and repeatedly replacing gas to remove impurities, thereby ensuring the space environment in the furnace; and stopping vacuumizing before the first-stage heat treatment, and supplementing nitrogen to ensure the slight positive pressure of the gas in the furnace so that the pressure in the furnace is slightly higher than the pressure outside the furnace.
Further, in the step S1, the wire diameter of the silicon dioxide is smaller than 150mm.
Further, in the step S1, the purity of the silica is 99.999998% or more.
Further, in the step S1, the pre-baking is performed for 0.5-3 hours at 300-400 ℃; the temperature rising rate of the pre-baking is 5-20 ℃/min.
Further, in the step S1, the temperature after the primary temperature rise is 750-850 ℃, and the primary temperature rise rate is 8-10 ℃/min.
Further, in the step S2, the temperature after the primary temperature rise is 1000-1050 ℃; the rate of one-time heating is 0.5-0.8 ℃/min.
Further, in the step S3, the temperature after cooling is 500-700 ℃, and the cooling rate is 0.1-0.2 ℃/min.
Further, in step S3, the temperature after cooling is 20-40 ℃.
A second object of the present invention is to provide a highly uniform quartz glass.
Compared with the prior art, the technical scheme of the invention has the following advantages:
(1) The first-stage heat treatment of the invention disturbs the stress distribution of the silicon dioxide inside near the center; the second stage of heat treatment is preceded by rapid cooling to break the temporary stress balance state in the quartz, because the viscosity of the quartz glass is relatively high, the quartz glass diffuses very slowly in a solid state, and under a certain temperature condition, the material endoplasm moves to a certain degree to solidify and can not rapidly resolve the stress, so that the temperature needs to be reduced once, and then the slow heating and cooling treatment process is carried out to ensure the complete release of the stress.
(2) The heat treatment method of the invention completely eliminates the stress in the quartz glass, uniformly diffuses the quartz glass and ensures that the material is not deformed.
(3) The heat treatment method saves the time of heating and cooling and reduces the energy consumption.
Drawings
In order that the invention may be more readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings, in which:
FIG. 1 is a schematic view showing a heat treatment method for producing quartz glass according to an embodiment of the present invention.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and specific examples, which are not intended to be limiting, so that those skilled in the art will better understand the invention and practice it.
Example 1
As shown in fig. 1, a heat treatment method for optimizing uniformity of synthetic quartz glass includes the steps of:
(1) Specification of the specification
Cleaning silicon dioxide and then placing the cleaned silicon dioxide into a furnace;
(2) Heating the furnace at 15 ℃/min to 350 ℃, preserving heat for 2 hours, and drying the furnace to remove water vapor;
(3) Vacuumizing in the heating process to reach a vacuum degree of 6×10 -4 Pa, removing impurities and oxygen in the furnace, repeatedly circulating for 4 times, and repeatedly replacing gas to remove impurities, thereby ensuring the space environment in the furnace;
(4) Stopping vacuumizing, supplementing nitrogen to ensure slight positive pressure of the gas in the furnace, and heating at 9 ℃/min to 800 ℃;
(5) Heating at 6 ℃/min to 1150 ℃;
(6) Incubation at 1150 ℃ for 12h, at which stage there is a homogenization process inside, but homogenization is not complete;
(7) Cooling at 1 ℃/min to 950 ℃, preserving heat for 12 hours, and breaking the balance of the movement of one substance in the current stage;
(8) Heating at 0.7deg.C/min to 1025deg.C;
(9) Heating to 1150 ℃ at 0.4 ℃/min;
(10) Preserving heat for 24 hours at 1150 ℃ for a time sufficient to ensure homogenization of the product inner mass;
(11) Cooling to 600 ℃ at 0.1 ℃/min, and slowly cooling to prevent new stress;
(12) Stopping heating at 600 ℃, and cooling to room temperature along with the furnace.
Example 2
As shown in fig. 1, a heat treatment method for optimizing uniformity of synthetic quartz glass includes the steps of:
(1) Specification of the specification
Cleaning silicon dioxide and then placing the cleaned silicon dioxide into a furnace;
(2) Heating the furnace at 15 ℃/min to 350 ℃, preserving heat for 2 hours, and drying the furnace to remove water vapor;
(3) Vacuumizing in the heating process to reach a vacuum degree of 6×10 -4 Pa, removing impurities and oxygen in the furnace, repeatedly circulating for 4 times, and repeatedly replacing gas to remove impurities, thereby ensuring the space environment in the furnace;
(4) Stopping vacuumizing, supplementing nitrogen to ensure slight positive pressure of the gas in the furnace, and heating at 9 ℃/min to 800 ℃;
(5) Heating at 6 ℃/min to 1150 ℃;
(6) Incubation at 1150 ℃ for 12h, at which stage there is a homogenization process inside, but homogenization is not complete;
(7) Cooling at 1 ℃/min to 950 ℃, preserving heat for 6 hours, and breaking the balance of the movement of one substance in the current stage;
(8) Heating at 0.7deg.C/min to 1025deg.C;
(9) Heating to 1150 ℃ at 0.4 ℃/min;
(10) Preserving heat for 24 hours at 1150 ℃ for a time sufficient to ensure homogenization of the product inner mass;
(11) Cooling to 600 ℃ at 0.1 ℃/min, and slowly cooling to prevent new stress;
stopping heating at 600 ℃, and cooling to room temperature along with the furnace.
Example 3
As shown in fig. 1, a heat treatment method for optimizing uniformity of synthetic quartz glass includes the steps of:
(1) Specification of the specification
Is put into after cleaning the silicon dioxideA furnace;
(2) Heating the furnace at 15 ℃/min to 350 ℃, preserving heat for 2 hours, and drying the furnace to remove water vapor;
(3) Vacuumizing in the heating process to reach a vacuum degree of 6×10 -4 Pa, removing impurities and oxygen in the furnace, repeatedly circulating for 4 times, and repeatedly replacing gas to remove impurities, thereby ensuring the space environment in the furnace;
(4) Stopping vacuumizing, supplementing nitrogen to ensure slight positive pressure of the gas in the furnace, and heating at 9 ℃/min to 800 ℃;
(5) Heating at 6 ℃/min to 1150 ℃;
(6) Incubation at 1150 ℃ for 6 hours, at which stage there is a homogenization process inside, but homogenization is not complete;
(7) Cooling at 1 ℃/min to 950 ℃, preserving heat for 6 hours, and breaking the balance of the movement of one substance in the current stage;
(8) Heating at 0.7deg.C/min to 1025deg.C;
(9) Heating to 1150 ℃ at 0.4 ℃/min;
(10) Preserving heat for 12h at 1150 ℃ for enough time to ensure homogenization of the product inner quality;
(11) Cooling to 600 ℃ at 0.1 ℃/min, and slowly cooling to prevent new stress;
stopping heating at 600 ℃, and cooling to room temperature along with the furnace.
Example 4
As shown in fig. 1, a heat treatment method for optimizing uniformity of synthetic quartz glass includes the steps of:
(1) Specification of the specification
Cleaning silicon dioxide and then placing the cleaned silicon dioxide into a furnace;
(2) Heating the furnace at a speed of 5 ℃/min to 300 ℃, preserving heat for 3 hours, and drying the furnace to remove water vapor;
(3) Vacuumizing in the heating process to reach a vacuum degree of 4×10 -4 Pa, removing impurities and oxygen in the furnace, repeating the cycle for 3 times, and repeatedly removing the replacement gasImpurities ensure the space environment in the furnace;
(4) Stopping vacuumizing, supplementing nitrogen to ensure slight positive pressure of the gas in the furnace, and heating at 8 ℃/min to 750 ℃;
(5) Heating at 4 ℃/min to 1100 ℃;
(6) Incubation at 1100 ℃ for 12h, at which stage there is a homogenization process inside, but homogenization is not complete;
(7) Cooling at 1 ℃/min to 800 ℃, preserving heat for 12 hours, and breaking the balance of the movement of one substance in the current stage;
(8) Heating at 0.5 ℃/min to 1000 ℃;
(9) Raising the temperature to 1100 ℃ at 0.2 ℃/min;
(10) Preserving heat for 24 hours at 1100 ℃, wherein the heat preservation time is enough to ensure homogenization of the product endoplasm;
(11) Cooling to 500 ℃ at 0.1 ℃/min, and slowly cooling to prevent new stress;
(12) Stopping heating at 500 ℃, and cooling to room temperature along with the furnace.
Example 5
As shown in fig. 1, a heat treatment method for optimizing uniformity of synthetic quartz glass includes the steps of:
(1) Specification of the specification
Cleaning silicon dioxide and then placing the cleaned silicon dioxide into a furnace;
(2) Heating the furnace at 20 ℃/min to 400 ℃, preserving heat for 0.5h, and drying to remove water vapor;
(3) Vacuumizing in the heating process to reach vacuum degree of 7×10 -4 Pa, removing impurities and oxygen in the furnace, repeatedly circulating for 5 times, and repeatedly replacing gas to remove impurities, thereby ensuring the space environment in the furnace;
(4) Stopping vacuumizing, supplementing nitrogen to ensure slight positive pressure of the gas in the furnace, and heating at 10 ℃/min to 850 ℃;
(5) Heating at 7deg.C/min to 1180deg.C;
(6) Incubation for 4h at 1180 ℃ at this stage, with a homogenization process inside, but homogenization is not complete;
(7) Cooling at 2 ℃/min to 950 ℃, preserving heat for 3 hours, and breaking the balance of the movement of one substance in the current stage;
(8) Heating at 0.8 ℃/min to 1050 ℃;
(9) Heating to 1180 ℃ at 0.5 ℃/min;
(10) Preserving heat for 6 hours at 1180 ℃ for a time sufficient to ensure homogenization of the product inner mass;
(11) Cooling to 700 ℃ at 0.2 ℃/min, and slowly cooling to prevent new stress;
(12) Stopping heating at 700 ℃, and cooling to room temperature along with the furnace.
Comparative example 1
(1) Specification of the specification
Cleaning silicon dioxide and then placing the cleaned silicon dioxide into a furnace;
(2) Heating the furnace at 15 ℃/min to 350 ℃, preserving heat for 2 hours, and drying the furnace to remove water vapor;
(3) Heating at 9 deg.c/min to 1150 deg.c;
(4) Incubation at 1150 ℃ for 12h, at which stage there is a homogenization process inside, but homogenization is not complete;
(5) Cooling to 600 ℃ at 0.1 ℃/min, and slowly cooling to prevent new stress;
(6) Stopping heating at 600 ℃, and cooling to room temperature along with the furnace.
Test case
The quartz glass produced in examples 1-3 and comparative examples 1-2 were subjected to uniformity test by ZYGO laser interferometer test using quartz glass not subjected to heat treatment as comparative example 2.
Table 1 shows the relevant parameters of the final measured homogeneity properties of the quartz glass:
TABLE 1
As can be seen from Table 1, the uniformity of the raw material of comparative example 2 is 40ppm, the uniformity of the material after one temperature rise and drop of comparative example 1 is improved to some extent, but the current use requirement is not satisfied, the uniformity of the material after 2 temperature rises and drops of examples 1 to 3 is obviously improved, the heat preservation time is prolonged, the uniformity of the material is effectively homogenized, and the uniformity of the quartz glass can be stabilized at 3 to 11ppm.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations and modifications of the present invention will be apparent to those of ordinary skill in the art in light of the foregoing description. It is not necessary here nor is it exhaustive of all embodiments. And obvious variations or modifications thereof are contemplated as falling within the scope of the present invention.
Claims (8)
1. A heat treatment method of high-uniformity quartz glass is characterized by comprising the following steps,
s1, carrying out vacuumizing treatment while pre-baking silicon dioxide, stopping vacuumizing before the first-stage heat treatment, supplementing nitrogen to ensure slight positive pressure of gas in a furnace, and then heating to realize the first-stage heat treatment; the temperature rise is divided into two temperature rises, namely a primary temperature rise and a secondary temperature rise; the secondary temperature rise is to raise the temperature to 1100-1180 ℃ at the speed of 5-7 ℃/min, and then preserving the heat for 4-12h; the temperature after the primary temperature rise is 750-850 ℃, and the primary temperature rise rate is 8-10 ℃/min;
s2, cooling after the first-stage heat treatment in the step S1, and heating to realize the second-stage heat treatment; the temperature rise is divided into two temperature rises, namely a primary temperature rise and a secondary temperature rise; the temperature is reduced to 800-950 ℃ at a speed of 1-2 ℃/min, and then the temperature is kept for 3-12h; the secondary temperature rise is to raise the temperature to 1100-1180 ℃ at the speed of 0.2-0.5 ℃/min, and then preserving the heat for 6-24 hours; the temperature after the primary temperature rise is 1000-1050 ℃; the primary heating rate is 0.5-0.8 ℃/min;
and S3, cooling, annealing and cooling after the second-stage heat treatment in the step S2 to obtain the high-uniformity quartz glass.
2. The heat treatment method of high-uniformity silica glass according to claim 1, wherein: in the step S1, the vacuum degree of the vacuuming treatment reaches 4 multiplied by 10 -4 -7×10 -4 Pa。
3. The heat treatment method of high-uniformity silica glass according to claim 1, wherein: in the step S1, the line diameter of the silicon dioxide is smaller than 150mm.
4. The heat treatment method of high-uniformity silica glass according to claim 1, wherein: in step S1, the purity of the silica is 99.999998% or more.
5. The heat treatment method of high-uniformity silica glass according to claim 1, wherein: in the step S1, the pre-baking is performed for 0.5 to 3 hours at the temperature of 300 to 400 ℃; the temperature rising rate of the pre-baking is 5-20 ℃/min.
6. The heat treatment method of high-uniformity silica glass according to claim 1, wherein: in the step S3, the temperature after cooling is 500-700 ℃, and the cooling rate is 0.1-0.2 ℃/min.
7. The heat treatment method of high-uniformity silica glass according to claim 1, wherein: in the step S3, the temperature after cooling is 20-40 ℃.
8. A highly uniform quartz glass produced by the heat treatment method according to any one of claims 1 to 7.
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| CN115108713B (en) * | 2022-06-15 | 2024-01-26 | 江苏亨芯石英科技有限公司 | Preparation process of quartz glass with high optical uniformity |
| CN115745384A (en) * | 2022-11-22 | 2023-03-07 | 宁波云德半导体材料有限公司 | Annealing method of thick quartz product |
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| JP6107701B2 (en) * | 2014-02-21 | 2017-04-05 | 信越化学工業株式会社 | Method for heat treatment of synthetic quartz glass and method for producing synthetic quartz glass substrate |
| CN106830651B (en) * | 2017-01-05 | 2019-08-02 | 富通集团（嘉善）通信技术有限公司 | The deshydroxy method for annealing of large-scale optical fiber prefabricating stick |
| CN108383365B (en) * | 2018-04-11 | 2020-09-15 | 中国建筑材料科学研究总院有限公司 | Annealing method of quartz glass |
| CN108675620A (en) * | 2018-05-21 | 2018-10-19 | 许昌市红外技术研究所有限公司 | A kind of fine annealing method of quartz glass |
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| CN113387550A (en) * | 2021-07-03 | 2021-09-14 | 四川神光石英科技有限公司 | Method for improving uniformity of quartz glass |
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