JPH09183629A - Crystalline glass and crystallized glass article produced by molding the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a crystalline glass capable of drawing forming under heating. SOLUTION: This crystalline glass consists of, by wt., 55-72% 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 O5 , 0-3% As2 O3 , and 0-3% Sb2 O3 , and depositing β-quartz solid solution or β-spodumene solid solution as a principal crystal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystallized glass and a crystallized glass article formed by molding the crystallized 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 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, it was also considered to redraw the glass before becoming crystallized glass, so-called raw glass, but since this kind of glass is designed to be easily crystallized by heating, the raw glass for redraw molding is used. When heated, devitrification inevitably occurs, making it impossible to control not only the dimensions but also the physical properties.

Therefore, in the case of precision processing of crystallized glass, the same mechanical processing 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 crystallized glass which can be redraw-molded and a crystallized glass article obtained by redraw-molding the crystallized glass.

[0008]

Means for Solving the Problems As a result of various experiments, the inventor has found that the crystallized glass can be redraw-formed, that it is easily softened by heating, and that the crystal phase is stable even when heated. Therefore, it was found that two points that the amount of crystals does not increase and devitrification does not occur are important, and a crystallized glass composition that can be redraw-molded was specified.

The crystallized glass of the present invention contains S by weight percentage.
_{iO 2 55~72%, Al 2 O} 3 16~30%, Li 2
O 1.5-2.8%, K ₂ O 2.1-10%, T
iO 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 to 0.9%, As ₂ O ₃ 0 to 3%, Sb ₂ O ₃ 0
~ 3%, β-quartz solid solution or β- as the main crystal
It is characterized in that a solid solution of spodumene is deposited.

The redraw-molded crystallized glass article of the present invention also has a weight percentage of SiO ₂ 55-72%, Al _{2
O 3 16~30%, Li 2 O} 1.5~2.8%,
K ₂ O 2.1-10%, TiO ₂ 1.3-5%, Z
rO ₂ 0 to 4%, TiO ₂ + ZrO _{2 2 to} 9%, Z
nO 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
A preformed body of crystallized glass, which is composed of 0 to 3% and Sb ₂ O _{3 of} 0 to 3% and in which β-quartz solid solution or β-spodumene solid solution is deposited as a main crystal, is heated to a temperature equal to or higher than the softening point. However, it is characterized by being stretch-formed.

[0011]

The reason why the composition of the crystallized glass is limited will be described below.

SiO ₂ is a main constituent component of glass as well as a crystal component, and its content is 55 to 72%,
It is preferably 62 to 68.5%. 55% SiO ₂
If it is less than the above, a crystallized glass having a uniform structure cannot be obtained,
When it is more than 72%, the softening point of the crystallized glass becomes high and the meltability at the time of melting the glass is deteriorated to cause a non-uniform state, so that partial devitrification easily occurs and redraw formability is remarkably lowered.

Al ₂ O ₃ is also a crystal constituent component, and its content is 16 to 30%, preferably 17 to 24%.
If Al ₂ O ₃ is less than 16%, the crystal becomes coarse. For this reason, the elongation during redraw molding is reduced, and the crystals stick out to the surface, which causes devitrification. On the other hand, if it exceeds 30%, devitrification is likely to occur during redraw molding.

Li ₂ O is an essential component as a constituent component of crystals, and its content is 1.5 to 2.8%, preferably 1.8 to 2.5%. If Li ₂ O is less than 1.5%, it is difficult to obtain a uniform crystallized glass, and if it is more than 2.8%, the crystallinity becomes too strong. For this reason, the amount of precipitated crystals is too large and the proportion of the glass phase becomes insufficient to make it difficult to soften, or crystallization easily progresses in the process of redraw molding.

K ₂ O is an essential component for controlling the crystallinity and has an important influence on the ratio of the glass phase and the softening point, and the content thereof is 2.1 to 10%, preferably 2.
It is 5 to 7%. When K ₂ O is less than 2.1%, the crystallinity becomes too strong and the proportion of the glass phase becomes insufficient,
Crystallization is facilitated during redraw molding. Further, the softening point of the crystallized glass becomes high. On the other hand, if it exceeds 10%, it becomes difficult to form crystallized glass.

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%, the crystal becomes coarse and redraw molding becomes difficult,
If it is more than 5%, a large amount of heterogeneous crystals are deposited and desired characteristics cannot be obtained.

Like TiO ₂ , ZrO ₂ is a component that acts as a nucleating agent, and its content is 0 to 4%, preferably 0.5 to 3%. If ZrO ₂ is more than 4%, it becomes 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 lowers the softening point of crystallized glass, and its content is 1 to 10%, preferably 2
~ 6%. If the content of ZnO is less than 1%, the softening point of the crystallized glass tends to be high, and if it is more than 10%, the stability of the crystal phase decreases.

MgO is a component that lowers the softening point of crystallized glass and constitutes crystals, and its content is 0.
~ 2.5%, preferably 0-2%. MgO is 2.
If it exceeds 5%, the crystallinity becomes too strong.

CaO is a component that lowers the softening point of crystallized glass, and its content is 0-4%, preferably 0-.
2%. If CaO is more than 4%, a large amount of different crystals will be precipitated.

BaO is also a component that lowers the softening point of crystallized glass, and the content thereof is 0 to 6%, preferably 0.
3%. When BaO is more than 6%, a large amount of different crystals are precipitated.

B ₂ O ₃ is also a component that lowers the softening point of crystallized glass, and its content is 0 to 7%, preferably 0.
~ 4%. If the B ₂ O ₃ content is more than 7%, a large amount of different crystals will be deposited.

Na ₂ O is 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 precipitated.

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 becomes strong.

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

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

The crystallized glass having the above composition 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 types, and heterogeneous crystals such as garnite 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 formed by the following method.

First, the weight percentage of SiO ₂ 55-72
%, 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 preformed body of crystallized glass is prepared which is composed of As ₂ O ₃ 0 to 3% and Sb ₂ O ₃ 0 to 3%, and in which β-quartz solid solution or β-spodumene solid solution is deposited as a main crystal. As the preform, either a preformed crystallized glass formed into a desired shape or a preformed crystallized glass formed into a desired shape and then crystallized is used. May be. The preferred composition range of the crystallized glass is SiO ₂ 62 to 68.5% in weight percentage.
Al ₂ O ₃ 17-24%, Li ₂ O 1.8-2.5
%, K ₂ O 2.5 to 7%, TiO ₂ 1.5 to 4.5
%, ZrO ₂ 0.5 to 3%, TiO ₂ + ZrO ₂ 3
~ 6%, ZnO 2-6%, MgO 0-2%, CaO
0-2%, BaO 0-3%, B ₂ O ₃ 0-4%, N
a ₂ O 0 to 2%, P ₂ O ₅ 0 to 0.7%, As ₂ O
_{It is 30 to} 1.5% and Sb ₂ O _{3 is 0 to} 1.5%.

Subsequently, the crystallized glass preform is stretch-molded while being heated to a temperature equal to or higher than the softening point, and further subjected to post-processing such as cutting, to obtain the crystallized glass article of the present invention. .

[0033]

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 Nos. 6 and 7), respectively.

[0035]

[Table 1]

[0036]

[Table 2]

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. These glasses were then heated in an electric furnace to crystallize. The crystallization was performed by heating each at the nucleation temperature and the crystal growth temperature shown in Tables 1 and 2 for 4 hours.

Next, the outer circumference of the crystallized glass was ground with a diamond tool to adjust the roundness to obtain a preform having a diameter of 400 mm. Then, as shown in FIG. 1, the annular electric furnace 1
The preform G is continuously fed at a speed of 5 mm / minute from the upper part of the above, and the lower end of the softened and extended downwardly formed compact is sandwiched by the roller 2 to form a thin rod of 1280 mm in diameter. The film was stretched at a speed of 1 / min to evaluate the moldability.
In the figure, g indicates a molded crystallized glass article. Redraw molding was performed at the temperatures shown in Tables 3 and 4. The evaluation results of each sample are shown in Tables 3 and 4.

[0039]

[Table 3]

[0040]

[Table 4]

As is apparent from the table, No. 1 which is an embodiment of the present invention. Each of the samples 1 to 5 showed good moldability. On the other hand, No. Sample No. 6 could not be stretched due to insufficient softening deformation. In addition, sample No. In No. 7, the crystal grains were coarse, the glass was cut during stretching, and devitrification was remarkable.

The main types of precipitated crystals were specified by X-ray diffraction (XRD). Redraw moldability (elongation, presence of devitrified matter) was evaluated as follows. Regarding the elongation, those in which cutting did not occur during redraw molding were evaluated as good, and those in which cutting and no elongation occurred were regarded as defective. With respect to the devitrified material, the surface of the sample after molding was visually observed, and those in which the devitrified material was not observed were classified as none and those in which the devitrified material was recognized.

[0043]

As described above, since the crystallized glass of the present invention can be redraw-molded, it hardly needs to be machined. Therefore, it is possible to provide a highly accurate molded product at low cost, and it can be applied to the fields of electronic parts, precision machine parts and the like.

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

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing redraw molding.

[Explanation of symbols]

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

Claims (2)

[Claims] 1. SiO ₂ 55-72% by weight percentage,
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 crystallized glass comprising 0 to 3% of s ₂ O _{3 and} 0 to 3% of Sb ₂ O ₃ and precipitating a β-quartz solid solution or a β-spodumene solid solution as a main crystal. 2. SiO ₂ 55-72% in weight percentage,
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 to 3% and Sb ₂ O ₃ 0 to 3%, and a preformed body of crystallized glass obtained by precipitating a β-quartz solid solution or a β-spodumene solid solution as a main crystal is A redraw-molded crystallized glass article, characterized by being stretch-formed while being heated to a temperature.