JPH0264031A - Manufacturing method of lump glass - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a method for producing glass by a sol-gel method.

[Prior art] In the production of glass by the conventional sol-gel method, a liquid sol having a desired glass component composition is prepared using fine particles of metal alkoxides and metal oxides as main raw materials, and the liquid sol is sealed into a desired shape. After gelling in a container to produce a wet gel, the wet gel is immersed in H, O,
The ethanol in the wet gel was replaced with 820, and the ammonium chloride in the wet gel was eluted into the 820, then taken out from HtO, heat treated, and vitrified.

[Problem to be Solved by the Invention] However, in the above-mentioned conventional technology, when immersing in the wet gel 820, a difference occurs in the amount of ethanol substitution and ammonium chloride elution inside the wet gel, which causes During the post-process heat treatment, the gel cracks,
There are problems in that cracks etc. occur and it is extremely difficult to produce large lumps of glass.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for easily producing large glass blocks by relaxing the distribution of the amount of ethanol and ammonium chloride generated inside a wet gel when the wet gel is immersed in HiO.

[Means for Solving the Problems 1 The method for producing bulk glass by the sol-gel method of the present invention is as follows:
A liquid sol with a desired glass component composition is prepared using metal alkoxide and metal oxide fine particles as main raw materials, and the liquid sol is gelled in a sealed container of a desired shape to produce a wet gel. Depending on the manufacturing method that involves heat treatment such as drying and sintering, the wet gel is
It is characterized by being irradiated with ultrasonic waves when immersed in O.

[Function] In the present invention, when a wet gel is immersed in H3O, ultrasonic waves are irradiated to increase the displacement of H, O and ethanol and the elution rate of ammonium chloride, thereby completely performing the above-mentioned displacement and elution. This makes it possible to produce a homogeneous wet gel and prevents cracks from occurring during the heat treatment process.

[Example 1 Ethyl silicate, ethanol, water, ammonia water (2
9%) were mixed in a molar ratio of 6:4:0°08, stirred for about 3 hours, and then allowed to stand at room temperature to grow and ripen the particles. Thereafter, by concentrating under reduced pressure, a silica fine particle dispersion with good dispersibility was prepared.The particle size distribution was measured by a centrifugal sedimentation method, and the average particle size was 0.54 μm.

Next, using 174 amounts of ethyl silicate, add 0.02N hydrochloric acid to give a weight ratio of 1:1, and stir for about 2 hours while cooling with water to prepare a hydrolyzed solution. did.

Here, the value of p) of the silica fine particle dispersion was adjusted to 4.5 by adding 2N hydrochloric acid, and then mixed with a hydrolyzed solution of ethyl silicate, and thoroughly heated until it became a homogeneous liquid sol. After stirring, 0.2N ammonia water was added to the liquid sol to adjust the pH value to 5.0, and a diameter of 3
The liquid sol was injected into a 0 cm cylindrical mold to a height of 10 cm, and the mold was further sealed and gelled to produce a wet gel. This wet gel was immersed in H2O and irradiated with ultrasound. After that, transfer it to a drying container and dry it for 70 minutes.
It was dried in a constant temperature dryer kept at °C, and the drying was completed in about 2 weeks, yielding a white gel with a diameter of 21 cm and a height of 7 cm. However, no ultrasound was applied during immersion in HzO. The wet gel has cracked.

The obtained gel body was once heated to 800 °C in an oxygen/nitrogen atmosphere.
℃, and various treatments such as promotion of condensation reaction, dehydration, removal of organic residues, etc., then heating to 1350℃ under reduced pressure to vitrify, further heating to 1750℃ in a nitrogen atmosphere, After holding for 30 minutes, it was slowly cooled.

The glass body thus obtained was a colorless cylinder with high transparency, and had a diameter of 15 cm, a height of 5 cI11, and a weight of 1940 g.

In addition, the physical properties of the obtained glass were consistent with those of silica glass, including Vickers hardness, specific gravity, coefficient of thermal expansion, infrared and near-infrared absorption spectra, and refractive index.

〔Effect of the invention〕

As described above, according to the method of the present invention, it is easy to produce a large lump of glass with excellent optical homogeneity.

Therefore, we believe that its application will expand not only to fields where quartz glass has been used up until now, but also to various fields that require particularly high quality, such as photomask substrates for ICs, optical fiber base materials, and special optical applications.

In addition, in the sol preparation step, B, Ti, Ge, Na,
Ca, LL, A1. Since it is possible to add various elements such as Te, Zr, Ce, Nd, and Cr, it is easy to manufacture a wide variety of multicomponent glasses and glasses that do not have existing compositions.

that's all

Claims (1)

[Claims] 1) Prepare a liquid sol with the desired glass component composition using metal alkoxide and metal oxide fine particles as main raw materials, gel the liquid sol in a sealed container of a desired shape to produce a wet gel, and then A method for producing bulk glass, which comprises irradiating ultrasonic waves when a wet gel is immersed in H_2O in a production method using a sol-gel method in which wet gel is vitrified by heat treatment such as drying and sintering.