JPH09183630A - Crystalline glass and crystallized glass article produced by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a crystalline glass capable of redrawing forming. SOLUTION: This crystalline glass consists of, by weight, 60-75% SiO2 16-30% Al2 O3 , 1.5-2.8% Li2 O, 2.1-10% K2 O, 1.3-5% TiO2 , 0-4% ZrO2 , 2-9% TiO2 +ZrO2 , 1-10% ZnO, 0-2.5% MgO, 0-4% CaO, 0-6% BaO, 0-7% B2 O3 , 0-4% Na2 O, 0-0.9% P2 O3 , 0-3% As2 O3 , and 0-3% Sb2 O3 , and has a property to deposite β-quartz solid solution or β-spodumene solid solution as a principal crystal.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a crystalline glass and a crystallized glass article produced by using the crystalline glass.

[0002]

2. Description of the Related Art Crystallized glass is a material exhibiting unique properties which are not present in amorphous glass due to various crystals deposited in the glass. For example, when crystals such as β-quartz solid solution and β-spodumene solid solution are precipitated, crystallized glass exhibiting extremely low expansion or negative expansion can be obtained. Moreover, crystallized glass generally has higher mechanical strength than glass due to the presence of these crystals.

In recent years, a crystallized glass having such excellent characteristics is precision processed into a thin rod shape, a thin tube shape, a thin plate shape or the like to produce a product requiring precise dimensional accuracy such as electronic parts and precision machine parts. Attempts have been made to apply it to the field.

[0004]

A forming method called a redraw forming method is known as a method for precisely processing glass. This method is to stretch-form a glass molded body that has been preformed to have an appropriate precision while heating it to a temperature equal to or higher than the softening point of glass, and continuously produce glass products that require high precision. It is widely used as a manufacturing method.

However, in the case of the conventional crystallized glass, it is difficult to perform the redraw molding like the glass for the following reasons. That is, the conventional crystallized glass has a problem that the heat resistance is too high, devitrification occurs during heating, stretching is difficult, and the amount of crystal changes due to heating, resulting in a large change in physical properties. This is because Therefore, redraw molding of glass before being crystallized glass, so-called crystalline glass, was studied. However, since this kind of glass is designed to be easily crystallized by heating, devitrification occurs inevitably when crystalline glass is heated for redraw molding, and not only the dimensions but also the physical properties cannot be controlled. .

Therefore, in the case of obtaining a precision-processed product made of crystallized glass, the same machining process as ceramics is inevitably required, resulting in an extremely high cost at present.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a crystallizable glass that can be redraw-molded and a crystallized glass article manufactured by using the crystallizable glass.

[0008]

The devitrification region of glass has a TTT (Time-Temperature-Transformatio) shown in FIG.
n) It can be represented by a diagram called a curve. TT
The T-curve is a plot of the time until devitrification (crystal) occurs when the glass is continuously heated at a certain temperature, where the vertical axis is temperature and the horizontal axis is time. The transparent region and the outside indicate the glass region.

When the crystalline glass is heated and molded, it is sufficient that the glass can be molded under a temperature / time condition other than the devitrification region in the figure in order to prevent devitrification. Conducted various experiments to identify a crystallized glass composition that could be redraw-molded.

That is, the crystalline glass of the present invention has a weight percentage of SiO ₂ 60 to 75% and Al ₂ O ₃ 16 to 30.
%, Li ₂ O 1.5 to 2.8%, K ₂ O 2.1 to 1
0%, TiO ₂ 1.3-5%, ZrO ₂ 0-4%,
TiO ₂ + ZrO ₂ 2-9%, ZnO 1-10%,
MgO 0-2.5%, CaO 0-4%, BaO 0
6%, B ₂ O ₃ 0 to 7%, Na ₂ O 0 to 4%, P _{2
O 5 0~0.9%, As 2 O} 3 0~3%, Sb 2 O
_{It is characterized by comprising 30 to} 3% and having a property of precipitating a β-quartz solid solution or a β-spodumene solid solution as a main crystal.

Further, the crystallized glass article of the present invention has a weight percentage of SiO ₂ 60 to 75% and Al ₂ O ₃ 16 to ₃ %.
0%, Li ₂ O 1.5 to 2.8%, K ₂ O 2.1 to
10%, TiO ₂ 1.3-5%, ZrO ₂ 0-4
%, TiO ₂ + ZrO ₂ 2-9%, ZnO 1-10
%, MgO 0-2.5%, CaO 0-4%, BaO
_{0~6%, B 2 O 3 0~7} %, Na 2 O 0~4%,
_{P 2 O 5 0~0.9%, As} 2 O 3 0~3%, Sb
_A preform of crystalline glass consisting of 0 to 3% of ₂ O ₃ and having a property of precipitating a β-quartz solid solution or a β-spodumene solid solution as a main crystal is stretch-molded while being heated and then crystallized. It is characterized by

[0012]

The crystallizable glass of the present invention has a viscosity (10 ^4.5 to 10 4.5-) capable of being subjected to redraw molding at a temperature higher than the upper limit temperature of the devitrification region.
10 ^6.5 poise).

The reason for limiting the glass composition in the crystalline glass of the present invention will be described.

SiO ₂ is a main constituent component of glass and also a crystal constituent component, and the content thereof is 60 to 75.
%, Preferably 64-72%. 60% SiO ₂
If it is less than the above range, the viscosity of the glass becomes too low, and the temperature range where redraw molding is possible overlaps with the devitrification region, resulting in devitrification during redraw molding. On the other hand, if the SiO ₂ content is more than 75%, the meltability of the glass when it is melted deteriorates, making it difficult to obtain a uniform glass.

Al ₂ O ₃ is also a component constituting the crystal,
Its content is 16 to 30%, preferably 17 to 24%. If the content of Al ₂ O ₃ is less than 16%, the crystallized glass article obtained by coarsening the crystal tends to deteriorate in properties,
If it exceeds 30%, the devitrification region expands, which is not preferable.

Li ₂ O is a constituent component of the crystal, and its content is 1.5 to 2.8%, preferably 1.8 to 2.5%.
It is. If the content of Li ₂ O is less than 1.5%, it is difficult to obtain a uniform crystallized glass. If the content of Li ₂ O is more than 2.8%, the devitrification region expands and the viscosity of the glass tends to be low, so that the redraw molding temperature range is It overlaps with the devitrification area.

K ₂ O is an essential component for controlling the devitrification region, and its content is 2.1 to 10%, preferably 2.5 to 7%. If K ₂ O is less than 2.1%, the devitrification region becomes too wide and the upper limit temperature of the devitrification region rises. On the other hand, if it exceeds 10%, the viscosity becomes too low and crystallization becomes difficult.

TiO ₂ is a component that acts as a nucleating agent during crystallization, and its content is 1.3 to 5%, preferably 1.5 to 4.5%. If the content of TiO ₂ is less than 1.3%, a crystallized glass having a dense structure cannot be obtained. If the content of TiO ₂ is more than 5%, a large amount of different crystals precipitate during crystallization, making it difficult to obtain desired characteristics.

Like TiO ₂ , ZrO ₂ is a component which acts as a nucleating agent during crystallization, and the content thereof is 0-.
It is 4%, preferably 0.5 to 3%. ZrO ₂ is 4%
If it is more, it will be difficult to melt the glass.

The total amount of TiO ₂ and ZrO ₂ is 2-9.
%, Preferably 3 to 6%. If the total amount of both is less than 2%, it becomes difficult to obtain a dense crystal, and if it exceeds 9%, the glass tends to be non-uniform.

ZnO is a component that promotes melting of glass, and its content is 1 to 10%, preferably 1.5 to 6%.
It is. If ZnO is less than 1%, the glass tends to be non-uniform, and if it is more than 10%, a large amount of heterogeneous crystals are precipitated.

MgO is also a component for promoting melting of glass, and its content is 0 to 2.5%, preferably 0 to 2%. If MgO is more than 2.5%, the glass tends to devitrify.

CaO is also a component that promotes melting of glass, and its content is 0 to 4%, preferably 0 to 2%. If CaO is more than 4%, devitrification tends to occur.

BaO is also a component that accelerates melting of glass, and its content is 0 to 6%, preferably 0 to 3%. If BaO exceeds 6%, devitrification tends to occur.

B ₂ O ₃ is also a component that promotes melting of glass, and its content is 0 to 7%, preferably 0 to 4%. If B ₂ O ₃ is more than 7%, the glass becomes non-uniform.

Na ₂ O is also a component that accelerates melting of glass, and its content is 0 to 4%, preferably 0 to 2%. If the content of Na ₂ O is more than 4%, a large amount of different crystals will be deposited.

P ₂ O ₅ has a function of making crystals finer,
Its content is 0 to 0.9%, preferably 0 to 0.7%. When P ₂ O ₃ is more than 0.9%, the devitrification region becomes wide.

As ₂ O ₃ and Sb ₂ O ₃ can be added as refining agents in amounts of up to 3% each, preferably up to 1.5% each.

In addition to this, SnO ₂ , PbO, Bi ₂ O _{3 and the} like can be added in a range not exceeding 5% in total.

The crystalline glass having the above composition has a property of becoming a low expansion crystallized glass having a β-quartz solid solution or a β-spodumene solid solution as a main crystal. It should be noted that the crystals to be precipitated are not limited to these two kinds, and heterogeneous crystals such as gannite may be precipitated as long as desired characteristics are not impaired.

Next, the crystallized glass article of the present invention will be described.

The crystallized glass article of the present invention is manufactured by the following method.

First, the weight percentage of SiO _{2 is} 60-75.
%, Al ₂ O ₃ 16 to 30%, Li ₂ O 1.5 to
2.8%, K ₂ O 2.1 to 10%, TiO ₂ 1.3
~ 5%, ZrO ₂ 0-4%, TiO ₂ + ZrO ₂ 2
~ 9%, ZnO 1-10%, MgO 0-2.5%,
CaO 0-4%, BaO 0-6%, B ₂ O ₃ 0-
7%, Na ₂ O 0 to 4%, P ₂ O ₅ 0 to 0.9%,
A preform of crystalline glass is prepared, which is composed of As ₂ O ₃ 0 to 3% and Sb ₂ O ₃ 0 to 3% and deposits a β-quartz solid solution or a β-spodumene solid solution as a main crystal. The preferred composition range of crystalline glass is SiO ₂
64-72%, Al ₂ O ₃ 17-24%, Li ₂ O
1.8-2.5%, K ₂ O 2.5-7%, TiO _{2
1.5~4.5%, ZrO 2 0.5~3%,} TiO 2
+ ZrO ₂ 3-6%, ZnO 1.5-6%, MgO
0-2%, CaO 0-2%, BaO 0-3%, B
_{2 O 3 0~4%, Na 2} O 0~2%, P 2 O 5 0~
_{0.7%, As 2 O 3 0~1.5} %, Sb 2 O 3 0
~ 1.5%.

Subsequently, the crystalline glass preform is stretch-formed while being heated. The heating temperature is a temperature higher than the maximum temperature of devitrification area, viscosity suitable for redraw molding (10 ^4.5 to
10 ^6.5 poise).

Then, the redraw-molded crystalline glass is crystallized to obtain the crystallized glass article of the present invention. If necessary, processing such as cutting may be performed after the redraw molding or after the crystallization.

The crystallized glass article thus obtained is a low expansion crystallized glass obtained by depositing a β-quartz solid solution or a β-spodumene solid solution as a main crystal. Note that the precipitated crystals are not limited to these two kinds, and if a small amount, different kinds of crystals such as gannite may be precipitated.

[0037]

EXAMPLES The present invention will be described below based on examples.

Table 1 shows examples of the present invention (Sample Nos. 1 to 1).
5) and Table 2 show comparative examples (Sample No. 6), respectively.

[0039]

[Table 1]

[0040]

[Table 2]

Each sample was prepared as follows.

First, glass raw materials prepared so as to have the composition shown in the table were put into a glass melting furnace, melted at 1650 ° C. for 24 hours, and then cast into a cylindrical shape having a diameter of 50 mm and a length of 500 mm. Next, the outer circumference was ground with a diamond tool to adjust the roundness, and a preform having a diameter of 40 mm was obtained.

The temperature of 10 ^4.5 poise (the maximum temperature at which redraw molding can be performed) and the maximum temperature in the devitrification region of the thus obtained preformed body were determined. Samples 1 to ⁵ had a temperature of 1250 to 1380 ° C. showing 10 ^4.5 poise and a devitrification upper limit temperature of 1160 to 1220 ° C., and a temperature showing 10 ^4.5 poise was 50 to 220 ° C. higher than the devitrification upper limit temperature. on the other hand,
Sample No. which is a comparative example. In No. 6, the temperature showing 10 ^4.5 poise was 1230 ° C., the upper limit temperature of devitrification was 1300 ° C., and the upper limit temperature of devitrification was 70 ° C. higher than the temperature showing 10 ^4.5 poise.

Then, as shown in FIG. 2, the preform G is continuously fed from the upper part of the annular electric furnace 1 at a speed of 5 mm / min, and the lower end of the compact which is softened and deformed and extends downward is set to the roller 2. 1) so that it becomes a thin rod with a diameter of 2.5 mm.
It was stretched at a speed of 280 mm / min to evaluate the moldability. In the figure, g indicates a molded crystalline glass. The redraw molding was performed at the temperature shown in the table. The evaluation results of each sample are shown in the table.

As is apparent from the table, No. 1 which is an example of the present invention is used. Each of the samples 1 to 5 exhibited appropriate viscosity, and devitrification did not occur, so that the moldability was good. On the other hand, in Comparative Example No. Using 6 samples,
What was redraw molded at a temperature higher than the devitrification upper limit temperature,
Although no devitrification was observed, the viscosity during molding was too low to control the shape. In the case of the redraw molding at a temperature of 10 ^4.5 poise, the glass remarkably devitrified and cutting occurred during stretching.

In addition, the sample No. 1 to
Sample No. 5 was heated again at 750 ° C. for 2 hours and then at 1100 ° C. for 1 hour. Sample Nos. 1 to 4 are β-spodumene solid solutions. In No. 5, crystallized glass having a β-quartz solid solution as a main crystal was obtained.
In addition, it was confirmed that each sample had almost no change in size and shape before and after reheating.

The temperature showing a viscosity of 10 ^4.5 poise was measured by the platinum ball pulling method. The upper limit temperature of devitrification was determined by holding the sample in a temperature-gradient furnace for a predetermined time, taking it out, and confirming the presence or absence of precipitated crystals by an optical microscope. The main crystal was investigated by X-ray diffraction.

[0048]

INDUSTRIAL APPLICABILITY As described above, the crystalline glass of the present invention can be redraw-molded, so that a highly accurate crystallized glass article can be produced. Therefore, it is suitable as a material for crystallized glass products used for electronic parts, precision machine parts and the like.

The crystallized glass article of the present invention has high dimensional accuracy and can be supplied at low cost, and is therefore suitable for electronic parts, precision machine parts and the like.

[Brief description of the drawings]

FIG. 1 is a graph showing a T-T-T curve.

FIG. 2 is an explanatory diagram showing redraw molding.

[Explanation of symbols]

 G crystalline glass preform g redraw molded crystalline glass 1 annular electric furnace 2 roller

Claims (2)

[Claims] 1. SiO ₂ 60-75% by weight,
Al ₂ O ₃ 16-30%, Li ₂ O 1.5-2.8
%, K ₂ O 2.1 to 10%, TiO ₂ 1.3 to 5
%, ZrO ₂ 0 to 4%, TiO ₂ + ZrO _{2 2 to} 9
%, ZnO 1-10%, MgO 0-2.5%, Ca
O 0-4%, BaO 0-6%, B ₂ O ₃ 0-7
%, Na ₂ O 0 to 4%, P ₂ O ₅ 0 to 0.9%, A
s ₂ O ₃ 0-3%, Sb ₂ O ₃ 0-3%, β
-Crystalline glass having the property of precipitating a quartz solid solution or a β-spodumene solid solution as a main crystal. 2. SiO ₂ 60-75% by weight,
Al ₂ O ₃ 16-30%, Li ₂ O 1.5-2.8
%, K ₂ O 2.1 to 10%, TiO ₂ 1.3 to 5
%, ZrO ₂ 0 to 4%, TiO ₂ + ZrO _{2 2 to} 9
%, ZnO 1-10%, MgO 0-2.5%, Ca
O 0-4%, BaO 0-6%, B ₂ O ₃ 0-7
%, Na ₂ O 0 to 4%, P ₂ O ₅ 0 to 0.9%, A
A preform of crystalline glass consisting of s ₂ O ₃ 0 to 3% and Sb ₂ O ₃ 0 to 3% and having the property of precipitating β-quartz solid solution or β-spodumene solid solution as the main crystal, A crystallized glass article, characterized by being crystallized after being stretch-formed while being heated.