JPS60239330A - Manufacture of glass block - Google Patents

Abstract

PURPOSE:To prevent cracking effectively by forming a devitrified layer on a substrate and a glass block having a desired composition on the devitrified layer by deposition. CONSTITUTION:Nd2O3-SiO2 glass contg. no Al2O3 is devitrified when the Nd2O3 content is increased to >= about 0.3mol%. The devitrified layer 5 of 0.1-0.3mm. thickness is formed on a quartz glass substrate 3 by feeding gaseous NdCl+ SiCl3 in such a mixing ratio that Nd2O3 is contained by >=0.3mol%. A gaseous NdCl3+AlCl3+SiCl3 mixture having a required composition is then blown into the lower end of a plasma flame 2 from a nozzle 1 to form a desired glass block 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a glass block, and in particular to a method of depositing and forming a desired glass block on a suitable substrate such as a glass substrate by a deposition method such as a chemical vapor deposition (CVD) method. When I did,
The present invention relates to a method for manufacturing a glass block that can effectively prevent cracks from forming in the target glass block.

Conventionally, the general method for manufacturing glass blocks is to deposit and form a block-shaped glass portion of a desired composition on a suitable substrate such as a glass substrate by CVD method, and then cut the substrate with a diamond cutter or the like. There is a way to remove it to get the desired glass block.

Although this method is relatively simple and excellent in principle, the problem is the difference in thermal expansion coefficient between the glass substrate used and the glass block deposited thereon.

This problem is especially serious when a common glass substrate is used as the substrate. Because the chemical composition of the substrate glass and the deposited glass are different, distortion due to the difference in thermal expansion coefficient between the two is large during the cooling process after the deposition process. This tended to result in cracks forming in the stacked glass blocks and eventually causing the entire block to break.

This risk increases as the size of the block increases, so since we are sticking to the most traditional direct deposition method, the only way to prevent cracks is to keep the size of the glass block small. ,It turns out that.

However, of course, there is a high demand for large glass blocks, so as a way to meet this demand,
An "intermediate glass glass" having a coefficient of thermal expansion intermediate between this substrate glass and the deposited glass block as a final product is first deposited on the substrate glass, and then a glass block is to be formed on this "intermediate glass". Methods have been proposed for depositing glasses of desired composition. The idea was to use the "intermediate glass" to alleviate and absorb stress and strain between the substrate glass and the glass block.

However, the method of introducing the concept of "intermediate glass" in this way involves bonding tube-shaped objects ranging from several millimeters to several tens of millimeters, such as a quartz glass tube and a borosilicate glass tube by continuously changing their composition. Even if it is possible to achieve this, there are many difficulties in applying it to objects with a large bonding area, such as the glass blocks discussed here, and it has been completely impossible in practice.

(The present invention was developed in view of the above points.) A method for producing a glass block that is sufficiently practical and that does not cause cracks even when a glass block of relatively large size is formed. This is what we intend to provide.

In order to achieve this objective, the present invention adopts a method in which a devitrification layer is first intentionally formed on a substrate, and then a glass block having a desired composition is deposited on the devitrification layer. This is based on the following knowledge.

In general, multi-component glasses are stably vitrified only within a compositional range, but devitrification occurs outside this range. Devitrification occurs due to the generation of fine crystals or microscopic phase separation, but in any case, in a devitrified state, a fine interface is generated inside.

Since these internal interfaces are relatively easily displaced by stress, the stress is relaxed or absorbed as a result.

Therefore, if a devitrification layer is intentionally formed between the substrate and the target deposited glass block as described above, the stress strain generated between the substrate glass and the glass block will be reduced. This can be reduced or eliminated by intervening a transparent layer.

Hereinafter, embodiments put into practical use by the applicant in accordance with the idea of the present invention will be described with reference to the accompanying drawings.

In this example, explanation will be made on the assumption that Nd203-A1203-5iOz glass blocks (for use as a telelaser active medium) are deposited on a quartz glass substrate by plasma torch CVD method. The NdCl3+ AlCl3+ 5iC13 gas was delivered using argon gas for transportation, and the pot line nozzle 1 was
Oxygen or oxygen-argon mixed plasma is oxidized by blowing into the lower end of the plasma flame 2, and about 170
The object (7) Nd203-Al2O is placed directly on the quartz glass substrate 3 which is heated to 0'O and is rotating and descending.
3-5 iOz glass-block 4 was deposited.

Therefore, as described above, cracks occur in the deposited glass block 4 due to distortion due to the difference in thermal expansion coefficient between the substrate glass 3 and the deposited target Nd203-AI203-5in2 super block 4. , which could grow and cause the entire block to break.

In contrast, in the present invention, a devitrification layer 5 with an appropriate thickness, for example, about 0.1-0.3 mm, is intentionally formed between the substrate glass 3 and the target deposited glass block 4. It has characteristics.

In this example, the devitrification layer is formed by the following procedure.

For Nd203-8lo2 gas containing Al2O3, devitrification occurs when Nd2O3 exceeds about 0.3 mol%. Therefore, first, Nd2O3 is 0.3 mol%
A devitrification layer 5 is intentionally formed on the quartz glass substrate 3 by flowing NdCl3+5iC13 gas having the above-mentioned mixing ratio. This thickness is, for example, 0.1-0.3+ as before.
Make it about am. Rather, it is formed to have a thickness sufficient to at least eliminate distortion.

After that, NdCl3+ AlCl3+5i of the desired composition is added to form the glass block 4 of the desired composition.
Blow C13 mixed gas through nozzle 1.

Actually, by such a method, Nd2O3 was 0.3 mol%, Al2O3 was 2.1 mol%, and 5i02 was 87.
A laser glass block having a composition of 6 mol % could be manufactured to a considerable size without cracking.

That is, it was possible to obtain results that indicate that the devitrification layer 5 sufficiently performs the stress relaxation function expected in the present invention.

It goes without saying that after the glass block 4 has been deposited, the devitrification layer 5 can be removed together with the substrate 1 by a suitable method such as a mechanical cutting method.

Of course, it is clear from the principles of the present invention described above that the present invention will still function effectively even when manufacturing glass blocks having compositions other than those shown in the above embodiments.

As described in detail above, the idea of the present invention of using a devitrification layer to eliminate strain and prevent the occurrence of cracks is that in addition to the basic effect of being able to obtain fairly large glass blocks without any inconvenience, the devitrification layer Special materials and equipment are generally not required to form the layers; the equipment required to form the desired deposited glass block is simply used and directed.

It is possible to obtain great effects from the viewpoint of productivity and rationality, such as by simply selecting unused materials from the group of materials used to obtain the composition of the final product.

[Brief explanation of the drawing]

The drawing is a schematic diagram of an apparatus to which the glass block manufacturing method of the present invention is applied. In the figure, l is a hot line nozzle, 2 is a plasma flame, 3 is a substrate, 4 is a deposited glass block to be produced, and 5 is a devitrification layer. Designated agent: Agency of Industrial Science and Technology procedural amendment book phantom year 1972? Showa sq year patent application No. 93! ;3 No. Otsu 2 Name of the invention Glass block manufacturing method 3 Person making the amendment Relationship to the case Patent applicant 114 Director of the Agency of Industrial Science and Technology Hirobe Kawada 4 Designated agent 7 Contents of the amendment (1) In the specification, Correct "Drawing" in line 6 of your letter to "Figure 1." (2) Fill in "Figure 1" on the attached drawing as shown in the attached sheet. Figure 1

Claims (1)

[Claims] A method for manufacturing a glass block, which comprises depositing a glass block on a substrate, first forming a devitrification layer on the substrate, and then depositing a devitrification layer on the devitrification layer. 1. A method for manufacturing a glass block, characterized in that the glass block of the composition is deposited.