JPS61236619A - Production of quartz glass - Google Patents

Abstract

PURPOSE:To obtain the quartz glass hard to generate a thermal deformation at a high temperature by adding Al or Al compounds to a sol or gel in the production of quartz glass by a sol-gel method. CONSTITUTION:Al or Al compounds such as AlCl3, Al2O3, etc. are added at either one process among the processes from the preparation of the gel to its sintering, in case of producing quartz glass by the sol-gel method wherein its material is metallic alkoxide or ultrafine powder silica. For example, Al (compounds) are added into a sol solution. Cr, dried gel or sintered gel is dipped in the solution containing Al ions or Al2O3 to diffuse Al into the gel, after drying to sinter it. By this method, Al atoms are introduced into quartz glass and the presence of traces of Al atoms improves the thermal resistance of quartz glass.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing quartz glass by a sol-gel method, and more particularly to a method for producing quartz glass with high heat resistance.

[Conventional technology]

The conventional method for synthesizing quartz glass using the sol-gel method uses high-purity alkyl silicate or high-purity ultrafine powder silica as raw materials, forms a sol with a solvent such as water or alcohol, gels it, and then processes it in an appropriate manner. Shrink and dry under the following conditions to form a dry gel. The dry gel was sintered under appropriate conditions to produce transparent quartz glass.

[Problem that the invention seeks to solve]

However, the above-mentioned conventional technology has the following drawbacks.

When quartz glass is used at high temperatures, the heat tends to cause thermal deformation such as warping and bending, which is a major problem when applied to various precision products such as thin film transistors.

The present invention is intended to solve these problems, and its purpose is to provide a method for manufacturing quartz glass that is less susceptible to thermal deformation at high temperatures.

[Means for solving problems]

The method for producing quartz glass of the present invention is a method for producing quartz glass by a sol-gel method using metal alkoxide or ultrafine powdered silica as a raw material, and is characterized by adding aluminum or an aluminum compound to the sol or gel. In addition, as for the addition method, A I Ot3 or At(OR)3 or Al is added to the sol solution.
It is a process in which 2O3 is added, or a dry gel or sintered gel is dissolved in a solution containing aluminum ions or Al2O3, and then diffused into the dry gel or sintered gel, and then dried and sintered. ] According to the above structure of the present invention, aluminum atoms are included in the quartz glass, and the presence of a trace amount of aluminum atoms improves the heat resistance of the quartz glass.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1゜Purified commercially available silicon ethoxide 208F (1 mol)
[101 N of hydrochloric acid 280] was added to the mixture, and the mixture was vigorously stirred for hydrolysis. Next, add ultrafine powdered silica (Aerosil QX50 with a surface area of 50rr?/P) to this solution at 90F (
1.5 mol) was added with stirring and ultrasonic vibration was applied. Further, clumps were removed by centrifugation, and aluminum chloride was added to 0.00745F (5.5 x 1 mol).
added. After stirring to make the mixture well homogeneous, 0.1N aqueous ammonia was added dropwise to adjust the pH value to 4.0. Next, this sol was poured into a polypropylene box-shaped container (W3
oxn3゜x, H10cm) so that the height was 1 tin.

The mixture was sealed tightly and allowed to stand at 20°C to form a gel, and was then stored overnight. Next, change the lid of the container to one with an opening ratio of 08%, and
When the temperature was raised to .degree. C. and dried at this temperature for 10 days, a stable dry gel that did not crack even when left at room temperature was obtained.

Subsequently, the glass was heated to 1400° C. and sintered using an appropriate heating program to obtain transparent quartz glass. When measuring the purity of this quartz glass, it was found that 5PPm of At was present, and in the conventional manufacturing method without adding At, At was OPPm and pA
The t content is increasing.

The quartz glass obtained in this example was 100×10×1.2
(, m), kept in an electric furnace as shown in Figure 1, and heated at 1150°C for 5 hours.
! : Thickness was 0.1 wm. However, when quartz glass with Oppm At obtained by the conventional manufacturing method is processed in the same way and treated at 1150°C for 3 hours, the amount of deflection is 0.5 mm, and the heat resistance is improved by the addition of < ht in this example. Example 2: Similar to Example 1, silicon ethoxide was hydrolyzed, and triethoxyaluminum 0.009 p ('5.5 x 10'' mol) was added to a sol solution containing ultrafine powdered silica. A transparent quartz glass was obtained by performing all the first steps in the same manner as in Example 1. When the purity of this quartz glass was measured, it was found that 4.0 ppm of At was present.

When this quartz glass is processed into a size of 100 x 10 x 1.2 and treated at 1150°C for 3 hours, the deflection l is 0. o
It can be seen that the heat resistance has improved in 8 cases.

Example 3 Silicon ethoxide was hydrolyzed in the same manner as in Example 1, ultrafine powdered silica was added, and the pH value was adjusted to 4. The OK-adjusted sol was gelatinized in the same container as in Example 1 and dried to obtain a dry gel. Heat the dry gel to 10% using an appropriate heating program.
It was heated to 00°C to form a porous sintered gel. On the other hand, a 1% aqueous solution of aluminum chloride was prepared, and the sintered gel was immersed therein. Subsequently, the sintered gel was dried and further heated to 1400° C. to form transparent quartz glass. When the purity of this quartz glass was measured, it was found that 50 ppm of At was present. When this quartz glass is processed into Box1oxt2 (mm) and treated at 1150°C for 3 hours, the amount of deflection is 00
It can be seen that the heat resistance is improved.

〔Effect of the invention〕

As described above, according to the present invention, by adding aluminum or an aluminum compound, the amount of thermal deformation at high temperatures can be reduced and heat resistance can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram for measuring the heat resistance of quartz glass. Above is Figure 1 in'q-

Claims (3)

[Claims] (1) In the low-temperature synthesis method of producing quartz glass by the sol-gel method using at least metal alkoxide or ultrafine powdered silica as raw materials, aluminum is added to the sol or gel at any step from sol preparation to sintering. Alternatively, a method for producing quartz glass characterized by adding an aluminum compound. (2) The step of adding an aluminum compound according to claim 1 is performed by adding AlCl_3 or Al to the sol solution.
A method for producing quartz glass, characterized in that (OR)_3 and Al_2O_3 are added. (3) The step of adding aluminum or an aluminum compound as described in claim 1 may cause gel, dry gel, or sintered gel to become aluminum ion or Al_
A method for producing quartz glass, comprising the steps of immersing it in a solution containing 2O_3, diffusing aluminum ions or Al_2O_3 into a gel or dry gel sintered gel, and then drying and sintering it.