JP2002154840A - Li2O-Al2O3-SiO2 CRYSTALLIZED GLASS - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an Li2O-Al2O3-SiO2 crystallized glass having clarification comparable to or higher than that of the conventional glass even when As2O3 is not used as a clarificant and satisfying product characteristics. SOLUTION: The Li2O-Al2O3-SiO2 crystallized glass has a composition comprising, by weight, 55-72% SiO2, 16-30% Al2O3, 1.5-4.0% Li2O, 2.1-10% K2O, 1.3-5.0% TiO2, 0-3% ZrO2, 1.5-8.0% TiO2+ZrO2, 1-10% ZnO, 0-2.5% MgO, 0-4% CaO, 0-6% BaO, 0-7% B2O3, 0-4% Na2O, 0-0.9% P2O5, 0.1-3% SnO2, 0-3% Sb2O3 and 0-3% Cl and having a TiO2 to SnO2 ratio of 3.3-45. A β-spodumene solid solution and/or a β-quartz solid solution has been deposited as principal crystals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to Li ₂ O—Al ₂ O
₃ relates -SiO ₂ based crystallized glass.

[0002]

2. Description of the Related Art Conventionally, front windows of oil stoves, wood stoves, etc., substrates for high-tech products such as color filters and image sensor substrates, setters for firing electronic components, shelf plates for microwave ovens, top plates for electromagnetic cooking, Li ₂ O—Al ₂ O ₃ is used as a material for window glass for fire doors, optical components and the like.
-SiO ₂ based crystallized glass is used.

[0003] Li ₂ O-Al ₂ O ₃ -SiO ₂ -based crystallized glass has excellent thermal characteristics because of its low coefficient of thermal expansion and high mechanical strength.

[0004]

However, when producing this type of crystallized glass, it is melted at about 1700 ° C. For this reason, As ₂ O ₃ that can generate a large amount of fining gas during melting at a high temperature is used as a fining agent added to the glass batch. That, As ₂ O ₃ fining contribute temperature range, because it matches well with the melting temperature, fining efficiency is the highest, is a very effective work in the molten glass.

[0005] However, As ₂ O ₃ is not preferable because it is highly toxic and may contaminate the environment during the glass manufacturing process or the treatment of waste glass.

An object of the present invention is to provide a Li ₂ O—Al ₂ O ₃ which has clarity equal to or higher than that of a conventional product and sufficiently satisfies product characteristics without using As ₂ O ₃ as a fining agent. -To provide a SiO ₂ -based crystallized glass.

[0007]

The Li ₂ O—Al _{2 of the} present invention is provided.
O ₃ —SiO ₂ crystallized glass is SiO ₂ 55% by weight.
_{~72%, Al 2 O 3 16~30} %, Li 2 O 1.5
_{~4.0%, K 2 O2.1~10%,} TiO 2 1.3~
5.0%, ZrO ₂ 0-3%, TiO ₂ + ZrO ₂
1.5-8.0%, 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%, SnO 2 0.1~3%,} Sb 2 O 3 0~3%,
Cl 0-3%, TiO ₂ / SnO ₂ 3.3-45, β-spodumene solid solution and / or
Alternatively, β-quartz solid solution is deposited.

[0008]

According to the present invention, a Li ₂ O—Al ₂ O ₃ —SiO ₂ system crystallized glass composition is specified so that excellent properties can be obtained without using As ₂ O ₃ .

[0009] From a number of tests and survey results, As_TwoO_Three
Not only greatly contributes to clarification, but also
Has also been shown to affect nucleation in
Was. Therefore, As_TwoO_ThreeWithout using
In order to obtain the characteristics, As _TwoO_ThreeS as an alternative fining agent
nO_TwoAdding, As_TwoO_ThreeIs reduced
The nucleation ability of the nucleating agent TiO_Two, ZrO_TwoContained
Optimizing the amount, nucleating agent TiO_TwoAnd fining agent S
nO_TwoThe importance of optimizing the ratio of
I found it.

Next, the reason for limiting the composition range of the crystallized glass in the present invention will be described.

The content of SiO ₂ is 55 to 72%, preferably 62 to 68.5%. If the content of SiO ₂ is less than 55%, a crystallized glass having a uniform structure cannot be obtained.
If it is larger than this, it becomes difficult to melt the glass.

The content of Al ₂ O ₃ is 16 to 30%, preferably 17 to 24%. If the content of Al ₂ O ₃ is less than 16%, the crystals become coarse and crystallized glass having a uniform structure cannot be obtained. On the other hand, if it exceeds 30%, devitrification tends to occur.

The content of Li ₂ O is 1.5-4.0%, preferably 1.8-3.0%. Li ₂ O is 1.5%
If it is less than 4.0%, it is difficult to obtain a uniform crystallized glass.
If it is larger, the crystallinity becomes too strong and the devitrification also becomes strong.

The content of K ₂ O is 2.1 to 10%, preferably 2.2 to 7%. If K ₂ O is less than 2.1%, the devitrification will increase. On the other hand, if it exceeds 10%, it becomes difficult to become crystallized glass.

TiO ₂ is a component which acts as a nucleating agent during crystallization, and its content is 1.3 to 5.0%, preferably 2.0 to 4.5%. If it is less than 2%, it is not possible to prevent a decrease in nucleation ability due to the absence of As ₂ O ₃ , and a crystalline glass having a uniform structure cannot be obtained. On the other hand, if it is more than 5%, a large amount of heterogeneous crystals will precipitate and desired characteristics cannot be obtained.

ZrO ₂ is a component that acts as a nucleating agent like TiO _2, and its content is 0 to 3%, preferably 0.5 to 2%. If ZrO ₂ is more than 3%, melting of the glass becomes difficult and the devitrification of the glass increases.

The total amount of TiO ₂ and ZrO ₂ is 1.5 to 8
%, Preferably 2.5 to 6%. The total amount of both is 1.
If it is less than 5%, it becomes difficult to obtain a dense crystal, and if it exceeds 8%, the glass tends to be non-uniform.

The content of ZnO is 1 to 10%, preferably 2 to 6%. If ZnO is less than 1%, the refining effect at the time of glass melting is reduced, and if it is more than 10%, the stability of the crystal phase is reduced.

The content of MgO is 0-2.5%, preferably 0-2%. If the content of MgO is more than 2.5%, the thermal expansion coefficient becomes too large.

The content of CaO is 0 to 4%, preferably 0 to 4%.
~ 2%. If the content of CaO is more than 4%, a large amount of heterogeneous crystals precipitate.

The content of BaO is 0 to 6%, preferably 0 to 6%.
~ 3%. If the content of BaO is more than 6%, the crystallinity becomes low and the thermal expansion coefficient becomes too large.

The content of B ₂ O ₃ is 0 to 7%, preferably 0 to 7%.
~ 4%. If B ₂ O ₃ is more than 7%, the crystallinity becomes low and the thermal expansion coefficient becomes too large.

Na ₂ O is a component that promotes the 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%, the crystallinity becomes low and the thermal expansion coefficient becomes too large.

P ₂ O ₅ has an action of making crystals fine, and its content is 0 to 0.9%, preferably 0 to 0.7%. When P ₂ O ₅ is more than 0.9%, the devitrification becomes strong.

SnO ₂ acts as an alternative fining agent for As ₂ O ₃ and also has a function as a nucleating agent. Its content should be 0.1-3%, preferably 0.1-1%. If the content of SnO ₂ is more than 3%, the devitrification of the glass increases, while if the content of SnO ₂ is less than 0.1%, the fining effect is not sufficient, and the crystallinity is reduced.

Further, when Sb ₂ O ₃ or Cl is added in the range of 0 to 3%, preferably 0 to 1.0%, the refining power is further improved.

The weight ratio of TiO ₂ / SnO ₂ is 3.3 to 4
5, preferably in the range of 7 to 43. TiO ₂ is As ₂
It is important to recover the decrease in nucleation power due to the absence of O ₃ , and SnO ₂ has a fining effect and the function of restoring the decrease in nucleation power due to the absence of As ₂ O ₃ . This ratio is 3.
If it is smaller than 3, metastable crystals will precipitate in the crystal, and the devitrification of the raw glass will increase. When it is larger than 45, clarity is reduced, and heterogeneous crystals are precipitated,
It becomes bad.

The crystallized glass having the above composition has a β-spodumene solid solution (Li ₂ O.Al ₂ O _3.
nSiO ₂ : n ≧ 4) and / or β-quartz solid solution (L
It is a low expansion crystallized glass obtained by precipitating i ₂ O.Al ₂ O ₃ .nSiO ₂ : n ≧ 2). Note that the precipitated crystal is not limited to this, and a crystal such as ganite (ZnO.Al ₂ O ₃ ) may be precipitated as long as desired characteristics are not impaired.

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

The Li ₂ O—Al ₂ O ₃ —SiO ₂ crystallized glass of the present invention can be produced as follows.

First, SiO 2 in% by weight_Two 55-72%,
Al_TwoO_Three 16-30%, Li_TwoO 1.5-4.0%,
K_TwoO 2.1-10%, TiO_Two 1.3-5.0%,
ZrO_Two 0-3%, TiO_Two+ ZrO_Two 1.5-8.
0%, ZnO 1-10%, MgO 0-2.5%, C
aO 0-4%, BaO 0-6%, B_TwoO_Three 0-7
%, Na_TwoO 0-4%, P_TwoO_Five 0 to 0.9%, Sn
O_Two 0.1-3%, Sb _TwoO_Three 0-3%, Cl 0
3% composition, TiO_Two/ SnO_TwoWeight ratio of 3.3
Adjust so that it is in the range of ~ 45.

Next, the prepared glass raw materials were mixed with 1550-17
After melting at 00 ° C. for 8 to 24 hours, molding is performed.

Subsequently, the glass molded body was held at 720 to 840 ° C. for 0.5 to 5 hours to form nuclei.
After heat treatment at 950 ° C for 0.5-5 hours, β-
Quartz solid solution precipitates, while 1 to 5 at 950 to 1200 ° C.
After heat treatment for a period of time, a crystallized glass in which a β-spodumene solid solution precipitates as a main crystal is obtained. The main crystal is β-
The coefficient of thermal expansion when the quartz solid solution is precipitated is 0 to 20 ×
10 ^-7 / ° C, the coefficient of thermal expansion when β-spodumene solid solution is precipitated is 10 to 30 × 10 ^-7 / ° C, and the coefficient of thermal expansion when both crystals are precipitated is 5 to 20 × 10 ^-7 / ° C. ° C. Thus, since these crystallized glasses have a low coefficient of thermal expansion, they have extremely excellent heat resistance.

The obtained crystallized glass is subjected to post-processing such as cutting and polishing, or is subjected to heat processing such as stretching, and is used for various purposes.

[0035]

EXAMPLES The following of the present invention based on examples Li ₂ O-
The Al ₂ O ₃ -SiO ₂ -based crystallized glass will be described.

Tables 1 and 2 show examples of the present invention (sample No. 1).
8 to 8) and Comparative Examples (Sample Nos. 9 to 11).

[0037]

[Table 1]

[0038]

[Table 2]

The batch raw materials are mixed in the form of oxides, hydroxides, halides, carbonates, nitrates, etc., so as to have the composition shown in the table, mixed uniformly, and then mixed with a platinum crucible in an electric furnace. After melting at 1550 to 1650 ° C. for 8 to 24 hours, the molten glass was then poured out onto a carbon platen to obtain a plate-like glass molded body. Next, this glass molded body was placed in an electric furnace to be crystallized. The sample No. 1 to
6 and sample no. In the heat treatment for crystallization of 9 to 11, the temperature is raised from room temperature to the nucleation temperature at a heating rate of 80 ° C./hour, maintained at the nucleation temperature of 780 ° C. for 2 hours, and further from the nucleation temperature to the crystal growth temperature. The temperature was increased at a rate of 40 ° C./hour, and the temperature was maintained at 1050 ° C. for 4 hours to cool the furnace. On the other hand, sample No. 7 and no. In the heat treatment for crystallization of No. 8, the temperature was raised from room temperature to the nucleation temperature at a heating rate of 80 ° C./hour, and maintained at the nucleation temperature of 740 ° C. for 2 hours.
The temperature was raised at a heating rate of / hour, the crystal growth temperature was maintained at 860 ° C. and 950 ° C. for 3 hours, respectively, and the furnace was cooled.

As is clear from the table, the sample No. 1 to 8 are optimization of alternative fining agents (SnO ₂ ) and nucleating agents (TiO ₂ , ZrO ₂ ) and TiO ₂
By adjusting the ratio of / SnO ₂ to 3.3 to 45, the clarity and devitrification show good results, and the coefficient of thermal expansion of the crystallization properties is excellent at 25 × 10 −7 / ° C. or less. It showed thermal properties. On the other hand, sample N which is a comparative example
o. Since No. 9 contained no fining agent, there were many bubbles in the glass and the fining was poor. Further, since the nucleating agent contained a large amount of ZrO ₂ , the devitrification was remarkable, and metastable crystals were precipitated in the crystal, and the desired properties were not satisfied. Samples Nos. 10 and 11 had a weight ratio of TiO ₂ / SnO ₂ outside the range of 3.3 to 45. 10
No. In No. 11, the devitrification was extremely poor.

The main types of the precipitated crystals were identified by X-ray diffraction (XRD). The coefficient of thermal expansion was 5
It was processed into a solid rod of 0 mm × 5 mmφ and measured with a dilatometer in a temperature range of 30 to 750 ° C. For the evaluation of clarity, the glass material was melted at 1550 to 1650 ° C. for 4 to 8 hours, and the glass sample after molding was observed. Was determined to be defective. The devitrification of the glass was evaluated by microscopic observation to determine whether a devitrified substance was present in the glass sample after molding. As a result, the symbol “な け れ ば” indicates that there was no devitrified material, and the symbol “×” indicates that it did.

[0042]

As described above, the Li ₂ O—Al ₂ of the present invention
O ₃ —SiO ₂ -based crystallized glass is used as a fining agent as As ₂ O ₃
Because it does not contain, there is no risk of polluting the environment. Furthermore, the crystallized glass of the present invention has a low coefficient of thermal expansion and excellent thermal properties, and is used for high-tech product substrates such as front windows of oil stoves, wood stoves, etc., and color filters and image sensor substrates. It is suitable as a material for electronic component firing setters, microwave oven shelves, electromagnetic cooking top plates, fire door windows, optical components, and the like.

Continued on the front page F term (reference) 4G062 AA01 BB01 BB06 DA06 DA07 DB04 DC01 DC02 DC03 DD01 DD02 DE03 DF01 EA03 EB01 EB02 EB03 EC03 ED01 ED02 ED03 EE01 EE02 EE03 EF01 EG01 EG02 EG03 FA01 FB03 FC01 FC01 FC01 FC03 FK01 FL01 GA01 GA10 GB01 GC01 GD01 GE01 HH01 HH03 HH05 HH07 HH09 HH11 HH13 HH15 HH17 HH20 JJ01 JJ03 JJ04 JJ05 JJ06 JJ07 JJ10 KK01 KK03 KK03 KK05 KK07 KK10 MM01 Q02 Q27 NN30 NN10

Claims (1)

[Claims] 1. The method of claim 1 wherein the weight percentage of SiO_Two 55-72%, Al_Two
O_Three 16-30%, Li_TwoO 1.5-4.0%, K_Two
O 2.1-10%, TiO_Two 1.3-5.0%, Z
rO_Two 0-3%, TiO_Two+ ZrO_Two 1.5-8.0
%, ZnO 1-10%, MgO 0-2.5%, CaO
 0-4%, BaO 0-6%, B _TwoO_Three 0-7%, N
a_TwoO 0-4%, P_TwoO_Five 0-0.9%, SnO_Two 
0.1-3%, Sb_TwoO_Three 0-3%, Cl 0-3%,
TiO_Two/ SnO_Two A main crystal having a composition of 3.3 to 45
Β-spodumene solid solution and / or β-quartz solid
Li characterized by depositing a solution_TwoO-Al_TwoO
_Three-SiO_TwoSystem crystallized glass.