KR20200083043A - LAS crystallized glass including Y2O3 and Fe2O3 and manufacturing method of the same - Google Patents

Abstract

The present invention relates to an LAS (Li_2O-Al_2O_3-SiO_2)-based crystallized glass including Y_2O_3 and Fe_2O_3 and a manufacturing method thereof, capable of ensuring transparency of the glass while smoothly performing formation of a crystal. According to the present invention, the method of manufacturing the LAS-based crystallized glass including Y_2O_3 and Fe_2O_3 includes: mixing a raw material of Li_2O, Al_2O_3, and SiO_2 or a precursor for generating the raw material through a heat treatment with an additive including Y_2O_3, Fe_2O_3, and a Zr-based compound; heating and melting a mixture of the raw material and the additive to prepare a melt; cooling the melt; and baking the cooled melt after molding the cooled melt, or molding the cooled melt after baking the cooled melt.

Description

LAS crystallized glass containing Ｙ2O3 and ２ｅ2O3 and a manufacturing method therefor {LAS crystallized glass including Y2O3 and Fe2O3 and manufacturing method of the same}

The present invention relates to a crystallized glass of LAS (Li ₂ O-Al ₂ O ₃ -SiO ₂ ) containing Y ₂ O ₃ and Fe ₂ O ₃ and a method for manufacturing the same, more specifically Li ₂ O, Al ₂ O ₃ , SiO ₂ raw material or a precursor for generating the raw material by heat treatment, and Y ₂ O ₃ , Fe ₂ O ₃ And mixing the additive containing the Zr-based compound; Preparing a melt by heating and melting the mixed raw material and additives; Cooling the melt; And LAS (Li ₂ O-Al ₂ O ₃ -SiO ₂ containing Y ₂ O ₃ and Fe ₂ O ₃ characterized in that it contains; A method of manufacturing a crystallized glass based on LA and a crystallized glass of LAS produced by such a method is provided.

Glass materials have the advantage of being transparent, but have the disadvantage that mechanical properties are inferior to ceramics. As a method to compensate for these drawbacks, crystallized glass (glass-ceramics) with improved mechanical properties has been developed by heat-treating a parent glass of a suitable composition to precipitate a collection of fine crystals inside the glass. Crystallized glass, unlike the parent glass, exhibits specific properties by crystals precipitated inside the glass.

In general, crystallized glass has the advantage of superior electrical, mechanical, thermal, and physical and chemical properties compared to the parent glass. Crystallized glass has the disadvantage that the permeability decreases due to interfacial scattering between the precipitated crystal phase and the glass phase, or a difference in refractive index, but if the properties such as the type, size, and refractive index of the crystal phase are well controlled, a crystallized glass in a transparent state can be obtained.

Crystallized glass has excellent electrical, mechanical, thermal, and physical and chemical properties, so it can be used as high-temperature materials, heat-resistant materials, electronic device materials, high-strength materials, building materials, and biomaterials.

Since crystallized glass can be produced by heat-treating a parent glass of a suitable composition, complex shapes can be easily obtained, and there is an advantage in that mechanical properties can be improved and thermal expansion coefficient can be adjusted by controlling the crystal grain size according to the heat treatment method. Among crystallized glass, LAS(Li ₂ O-Al ₂ O ₃ -SiO ₂ )-based glass has been actively studied because it has the advantage of having a coefficient of thermal expansion close to 0 and high permeability.

Crystallization of glass is divided into two stages, nucleation and crystal growth, and the main crystal phase begins to form in the nucleation stage, and the particle size of the main crystal phase is determined in the crystal growth stage. In general, in order to maintain transparency, the crystal size should be 0.1 µm or less, which is smaller than the wavelength of visible light, or the optical anisotropy of the crystal phase should be small, and the difference in refractive index between the crystal phase and the glass phase should be small.

Zirconia (ZrO ₂ ) or zircon (ZrSiO ₄ ) is mainly used as a nucleating agent for nucleation of LAS crystallized glass, and β-quartz, β-spodumene, and β as crystal phases. -Eucryptite (β-eycryptite) crystals may be precipitated. However, the zirconia (ZrO ₂ ) has a very high melting point of 2680° C., and the specific gravity is also high at 6 g/cm 3, which causes a problem that the content of zirconia (ZrO ₂ ) increases in the lower part when the glass is melted in large quantities. Similar problems exist in the case of zircons. In addition, a certain level of problems has arisen in securing the homogeneity of the glass.

However, according to the manufacturing method of such a glass, the thermal expansion coefficient is generally stable up to a temperature of less than 800°C, but there is a problem in that the thermal expansion coefficient increases rapidly at around 800°C.

In addition, in order to solve the above-mentioned problems of homogeneity, zirconium oxychloride (ZOC, ZrOCl ₂ ) was used instead of ZrO ₂ , and conventional ZOC was mainly used to synthesize a very small amount of glass by a sol-gel method, and was used as a melting furnace. It was not used when producing glass using.

However, ZOC generates chlorine gas, which can lead to environmental pollution and corrosion of refractories and machinery. In addition, the chlorine gas capture facility is complicated and requires advanced operation technology, so it is difficult to secure the facility.

Korea Registered Patent 10-1760039 Korea Registered Patent 10-0614886 Republic of Korea Patent Special 2003-0040438

The present invention has been devised to solve the above-mentioned problems, and the present invention is a LAS containing Y ₂ O ₃ and Fe ₂ O ₃ that ensures the transparency of the glass and achieves homogenization of the glass while facilitating the formation of crystals. It is an object to provide a (Li ₂ O-Al ₂ O ₃ -SiO ₂ )-based crystallized glass and a manufacturing method thereof.

In addition, another object of the present invention is to improve the stability of the LAS crystallized glass at a high temperature by shifting the temperature of the rapid increase in the coefficient of thermal expansion of the LAS crystallized glass to a higher temperature than before.

In addition, another object of the present invention is to secure thermal expansion coefficient stability and thermal shock resistance at the use temperature by promoting thermal expansion coefficient stability when used at a high temperature of the LAS crystallized glass.

In addition, the present invention has a problem in that chlorine gas that causes pollution of the refractory and mechanical equipment in the process of using ZOC in the manufacture of glass, and prevents this and can protect the environment and equipment, Another object is to prevent the need to secure additional pollution prevention equipment such as chlorine gas removal equipment.

In addition, the present invention suppresses the precipitation phenomenon that may occur in the manufacturing process of glass by using Zr(SO ₄ ) ₂ with low density and melting point as an additive, lowers the manufacturing temperature, and the additive is homogeneously inside the glass. It is another object to allow uniform crystal growth by penetrating into the furnace.

The present invention by the addition of _{Zr (SO 4) 2, Zr} (SO 4) , and ₂ denotes a refining effect, be the removal of the air bubbles take place more effectively with a refining agent such as SnO ₂ used in the conventional, SO _x gas Another object is to provide a crystallized glass based on LAS (Li ₂ O-Al ₂ O ₃ -SiO ₂ ) containing Y ₂ O ₃ and Fe ₂ O ₃ which is easy to collect because it only occurs, and a manufacturing method thereof .

In order to achieve the above object, the present invention includes a Li ₂ O, Al ₂ O ₃ , SiO ₂ raw material or a precursor for generating the raw material by heat treatment, and Y ₂ O ₃ , Fe ₂ O ₃ and Zr-based compounds Mixing the additives; Preparing a melt by heating and melting the mixed raw material and additives; Cooling the melt; And LAS (Li ₂ O-Al ₂ O ₃ -SiO ₂ containing Y ₂ O ₃ and Fe ₂ O ₃ characterized in that it contains; It provides a method for producing a)-based crystallized glass.

The Zr-based compound is preferably Zr(SO ₄ ) ₂ .

It is preferable that the Zr(SO ₄ ) ₂ is weighed and added to produce 1 to 2 parts by weight of ZrO ₂ based on the glass composition.

It is preferable that Y ₂ O ₃ and Fe ₂ O ₃ are added in excess of 0 to 1 part by weight, and more than 0 to 0.2 part by weight, respectively, based on the glass composition.

When Y ₂ O ₃ and Fe ₂ O ₃ are simultaneously added, Y ₂ O ₃ is preferably added in an amount of 0.1 to 1 part by weight, and Fe ₂ O ₃ is added in an amount of 0.2 to 1 part by weight.

When the Zr-based compound is Zr(SO ₄ ) ₂ , the glass transition temperature is preferably at least 855°C.

In addition, the present invention is a LAS (Li ₂ O-Al ₂ O ₃ -SiO ₂ )-based crystallized glass, a mixing agent is added during the manufacturing process of the glass, and the mixing agent is a mixture of Y ₂ O ₃ and Fe ₂ O ₃ It provides a crystallized glass of LAS (Li ₂ O-Al ₂ O ₃ -SiO ₂ ) containing Y ₂ O ₃ and Fe ₂ O ₃ characterized in that.

The Y ₂ O ₃ is added more than 0 and 1 part by weight or less based on the total glass composition, and Fe ₂ O ₃ is preferably added more than 0 and 0.2 part by weight or less.

When Y ₂ O ₃ and Fe ₂ O ₃ are simultaneously added, Y ₂ O ₃ is preferably added in an amount of 0.1 to 1 part by weight, and Fe ₂ O ₃ is added in an amount of 0.2 to 1 part by weight.

The melting step is preferably a step of heating at 1550 ~ 1700 ℃ for 2 to 4 hours to melt.

The cooling step is preferably a step of cooling for 30 minutes to 1 hour and 30 minutes at a temperature elevated by 10° C. to 25° C. than the glass transition temperature of the glass.

According to the present invention as described above, while smoothly generating crystals, it is possible to secure the transparency of the glass and to expect an effect of achieving homogenization of the glass.

In addition, the present invention can be expected to improve the stability of the LAS crystallized glass in use at high temperatures by shifting the temperature of the rapid increase in the coefficient of thermal expansion of the LAS crystallized glass to a higher temperature than in the prior art.

In addition, the present invention can be expected to have an effect of securing thermal shock resistance as well as thermal expansion coefficient stability at the use temperature by promoting the thermal expansion coefficient stability when used at a high temperature of the LAS crystallized glass.

In addition, the present invention has a problem in that chlorine gas that causes pollution of the refractory and mechanical equipment in the process of using ZOC in the manufacture of glass, and prevents this and can protect the environment and equipment, In addition, it is possible to expect an effect of not requiring securing of pollution prevention equipment such as a chlorine gas removal facility.

In addition, the present invention suppresses the precipitation phenomenon that may occur in the manufacturing process of glass by using Zr(SO ₄ ) ₂ with low density and melting point as an additive, lowers the manufacturing temperature, and the additive is homogeneously inside the glass. It can be expected to penetrate into the structure to enable uniform crystal growth.

The present invention is by the addition of _{Zr (SO 4) 2, Zr} (SO 4) , and ₂ denotes a refining effect, be the removal of the air bubbles take place more effectively with a refining agent such as SnO ₂ used in the conventional, SO _Since only gas is generated, it is possible to expect an effect of easy collection.

1 is a graph showing the change in the coefficient of thermal expansion of LAS glass to which Y ₂ O ₃ and Fe ₂ O ₃ are added according to Preparation Example 4 of the present invention.
Figure 2 is a graph showing the change in the coefficient of thermal expansion of LAS glass to which Y ₂ O ₃ and Fe ₂ O ₃ are added by Preparation Example 5 of the present invention.
3 is a graph showing the change in the thermal expansion coefficient of LAS glass to which Y ₂ O ₃ and Fe ₂ O ₃ are not added according to Preparation Example 0 in the present invention.
4 is a TMA analysis result of the mother glass made in the manufacturing process of the embodiments of the present invention and corresponding comparative examples.
5 is a TMA analysis result of the embodiments and comparative examples of the present invention.
Figure 6 shows a photo crystallized with a β-quartz solid solution by heat treatment at 860 ℃ according to an embodiment of the present invention.
7 is a SEM image for comparing the size and homogeneity of the crystal phase of the Examples and Comparative Examples of the present invention. Here, pictures of β-spodumene with distinct comparison results are included.
8 is a graph showing the measurement of three-point bending strength using the specimens of Example 1, Comparative Example 1, Comparative Example 3, and Comparative Example 5 of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the following description, only parts necessary for understanding the operation according to the embodiment of the present invention are described, and descriptions of other parts will be omitted so as not to obscure the gist of the present invention.

The terms or words used in the present specification and claims described below should not be construed as being limited to ordinary or lexical meanings, and the inventor is appropriate as a concept of terms to describe his or her invention in the best way. It should be interpreted as a meaning and a concept consistent with the technical idea of the present invention based on the principle that it can be defined as such. Therefore, the embodiments shown in the embodiments and the drawings described in this specification are only the most preferred embodiments of the present invention, and do not represent all of the technical spirit of the present invention, and various equivalents that can replace them at the time of this application It should be understood that there may be water and variations.

A. Y ₂ O ₃ Wow Fe ₂ O ₃ To Effect of temperature when the coefficient of thermal expansion increases rapidly when added

Hereinafter, it was examined how the thermal expansion coefficient increases when Y ₂ O ₃ and Fe ₂ O ₃ are added.

<Production Example>

After mixing Li ₂ O, Al ₂ O ₃ , SiO ₂ raw material or a precursor for generating the raw material by heat treatment, and additives including Y ₂ O ₃ , Fe ₂ O ₃ and Zr-based compounds, using a ball mill It was put in a platinum crucible and kept at 1600°C for 2 hours to melt. Here, ZOC was used as the Zr-based compound.

Further, in the present invention, Y ₂ O ₃ and Fe ₂ O ₃ are added. Currently, there is a property that the viscosity of the glass is very high due to the properties of the raw material used for crystallized glass. The high viscosity of glass means that very high thermal energy is consumed in the process of melting the glass. Therefore, although some alkali oxides and alkaline earth oxides are added to lower the melting temperature, the coefficient of thermal expansion increases, making it difficult to set it close to zero. As a result, some other oxides are added to compensate for this shortcoming, which is a lanthanide element, Y ₂ O ₃ is a lanthanide element, and the increased thermal expansion coefficient due to the alkali group element used to lower the viscosity of the crystallized glass is zero again. It plays a role of approaching.

In addition, Y ₂ O ₃ has an advantage in that a transparent crystallized glass can be produced while the transmittance of visible light is excellent due to a tendency to make the size of crystals generated in the crystallized glass uniform and small. That is, there is an effect of suppressing the crystal growth rate. However, when Y ₂ O ₃ is used in an amount of 1% by weight or more based on the weight of the composition, the generation of crystals is hindered, and the activation energy is increased to intensively change the crystallization of the bulk state to the surface. Therefore, an appropriate amount of Y ₂ O ₃ should be used to play a role in crystal formation and viscosity control.

In addition, when Fe ₂ O ₃ is added within a certain range, it has the effect of lowering the formation temperature of the transparent crystalline phase, β-quartz phase, thereby reducing energy during the manufacturing process. It serves to prevent the transition from the β-quartz phase to the β-spodumene phase, and has the advantage of producing a crystallized glass through which a wider range of visible light is transmitted.

The reason why the β-quartz phase is important is because it is a crystalline phase having a zero (0) thermal expansion coefficient. When the temperature that is transferred to the β-spodumene phase is low, the amount of transition increases, and thus the properties of the thermal expansion coefficient are completely different. That is, for example, the product glass use temperature is 800° C., but when the crystal phase transitions at 800° C., the longer the use time, the larger the β-quartz is converted to β-spodumene. However, there is an effect of increasing the transition temperature from β-quartz to β-spodumene by using Fe ₂ O ₃ . Therefore, more β-quartz residual amount can be maintained.

However, when a large amount of Fe ₂ O ₃ is used, the glass is darkly colored and it is difficult to produce a uniform glass by preventing heat rays from moving to the bottom of the melting furnace during the glass manufacturing process. .

Therefore, in the present invention, Y ₂ O ₃ and Fe ₂ O ₃ were used in combination, and the thermal expansion coefficient rapidly increased at around 800° C. like Example (ECK) glass in which Y ₂ O ₃ and Fe ₂ O ₃ were not used at all. Unlike glass with a different composition, such as KI-SKG-S and KI-SKG-Adv, which used two raw materials properly, the temperature range showed an increase of 40 to 50℃, which is the thermal shock temperature and It has the effect of raising the use temperature. That is, Y ₂ O ₃ is added in excess of 0 to 1 part by weight based on the total composition of the glass, and Fe ₂ O ₃ is preferably added in an amount of more than 0 and 0.2 parts by weight or less. The above numerical range is a critical significance for showing that the temperature range increases by 40 ~ 50℃ as above, and if it deviates, the thermal expansion coefficient does not rise or is insignificant.

In short, the fact experimentally identified in the present invention is that Fe ₂ O ₃ and Y ₂ O ₃ have similar functions in that β-quartz increases the temperature at which phase is converted to β-spodumene. Since there are features in that it was possible to solve the disadvantages or insufficient points that occurred when using Fe ₂ O ₃ only or excessively using Y ₂ O ₃ by anti-complement, Y ₂ O ₃ and Fe ₂ O ₃ Are organically linked to each other.

Looking at the function of each component in more detail, Y ₂ O ₃ expresses the effect of making the resulting crystal phase fine, and when fine crystals are generated, it means that the uniformity is improved during growth, and also the stability of thermal and mechanical properties. do. When added with Fe ₂ O ₃ , the lower limit is 0.1% by weight, and the upper limit is preferably 1% by weight from the viewpoint of lowering crystallinity. That is, when Y ₂ O ₃ is based on the weight of the crystallized glass, it is preferable that 0.1 to 1% by weight thereof is included.

In addition, Fe ₂ O ₃ is the main purpose of the effect of delaying the phase transition of β-quartz prepared to β-spodumene, and when added together with Y ₂ O ₃ , 0.2 wt% is set as the lower limit. In order to minimize the change in the crystallization mechanism and permeability, it is preferable to set the upper limit of 1% by weight. That is, when Fe ₂ O ₃ is based on the weight of the crystallized glass, it is preferably contained 0.2 to 1% by weight.

In addition, the glass to which Y ₂ O ₃ and Fe ₂ O ₃ is added has a temperature at which the crystallization starts is 10 to 15° C. lower than that of the glass to which it is not added, and thus the crystal structure is densified, and Y ₂ O ₃ and The composition in which Fe ₂ O ₃ was mixed (composition of KI-SKG-Adv) increased the 3-point bending strength by 13% compared to the composition in which Y ₂ O ₃ and Fe ₂ O ₃ were not mixed (EKC).

Next, it was melted by heating at 1550 to 1700°C for 2 to 4 hours. In order for the LAS glass to melt, it must be at least 1550°C. In addition, sufficient melting is achieved by melting for at least 2 hours. Here, the melting temperature is related to the viscosity, and must be melted to be less than log η=2 (also referred to as 100 poise). The melting temperature above has a critical significance as a range for satisfying the above viscosity conditions. That is, in order to maintain a viscosity value below the above viscosity value, a melting temperature of at least 1550°C is required, and an excess of 1700°C becomes an unnecessary melting temperature.

Next, after the molten glass was molded into a graphite mold, the mother glass was prepared by cooling (slow cooling) for about 1 hour at a temperature elevated by about 20° C. from the glass transition temperature (Tg). Then, the mother glass was heat treated at 720° C. for 3 hours, and then heat treated at 870° C. for 3 hours to precipitate β-quartz crystals to prepare crystallized glass.

However, the cooling temperature may be achieved at a temperature elevated by a range of 10 to 25°C compared to the glass transition temperature.

The cooling temperature is significant as a temperature range for completely removing the stress.

The slow cooling of the glass is to remove the thermal stress on the surface and inside of the glass. To remove this, if heat is applied at a slightly lower viscosity than the glass transition point and cooled slowly, the permanent strain is not newly introduced even after rapid cooling. As described above, the slow cooling temperature related to viscosity is 15 to 25°C higher than the glass transition point, and the time is slightly different depending on the glass thickness, but is around 30 minutes.

Meanwhile, in Table 1 below, Manufacturing Example 0 does not include both Y ₂ O ₃ and Fe ₂ O ₃ , Manufacturing Example 1 includes only Y ₂ O ₃ , and Manufacturing Example 2 is Fe ₂ O _It contains only ₃ , Preparation Example 3 includes both Y ₂ O ₃ and Fe ₂ O ₃ , but was set to contain an amount that is less than the preferred amount presented in the present invention.

Composition range Preparation Example 0 Preparation Example 1 Preparation Example 2 Preparation Example 3 Preparation Example 4 Preparation Example 5 Category/ wt% ECK KI-SKG-Y KI-SKG-F KI-SKG-N KI-SKG-ADV KI-SKG-S SiO2 61-66 64.70 64.18 63.88 63.95 64.00 64.40 Al2O3 19-23 20.90 20.15 20.15 20.15 20.00 20.60 Li2O 3-5.5 3.67 3.75 3.72 3.72 3.72 3.60 BaO 2-4.5 2.50 2.55 2.45 2.45 2.45 2.20 TiO2 2-4.5 2.80 2.80 2.80 2.80 2.80 2.65 ZrO2 1.5-4 1.68 1.67 1.60 1.60 1.60 1.60 ZnO 0-3 2.00 2.00 2.00 2.00 2.00 2.00 P2O5 0-3 1.77 1.54 1.63 1.54 1.00 Na2O 0-2 0.50 1.05 0.90 CaO 0-2 0.37 K2O 0-2 0.85 0.75 MgO 0-2 0.15 0.15 0.15 Fe2O3 0-0.6 0 0.53 0.05 0.27 0.37 Y2O3 0-0.6 0.33 0 0.05 0.22 0.22 SnO2 0-0.6 0.53 0.55 0.55 0.55 0.50 0.46 Total 100.00 100.00 100.00 100.00 100.00 100.00 LAS molar ratio LAS amount (wt%) TiO2: ZrO2 molar ratio Nucleation agent content (wt%) Batch amount (g) Crucible type Pt Pt Pt Pt Pt Pt Whether to use Stirrer x x x x x x Melting Temp.(℃) 1680 1680 1680 1680 1680 1680 Melting hour 3 3 3 3 3 3 Annealing Temp.(℃) 650 600 600 600 600 600 Experiment result Viscosity Solubility (upper and lower) Homogeneity (upper and lower) Chengjing Province (upper and lower) color Brown Brown Dark brown Light brown Dark brown Dark brown Uniqueness Thermal properties of parent glass Transition temperature (℃) 690 Heat peak start temperature (℃) 863 866 858 867 875 851 Maximum heating peak temperature (℃) 882 886 877 887 893 882 Coefficient of thermal expansion (10 ^-7 /℃): 50-600℃ 4.54 Heat treatment Nucleation temperature (℃) 710-730 710-730 710-730 710-730 710-730 710-730 Crystal growth temperature (℃) 850-890 850-890 850-890 850-890 850-890 850-890 Crystallized glass thermal properties Transition temperature (℃) Thermal shock temperature℃ 750℃ satisfaction 650℃ satisfaction 700℃ satisfaction 700℃ satisfaction 750℃ satisfaction 750℃ satisfaction Coefficient of thermal expansion (10 ^-7 /℃): 50-600℃ -2.60 -7.98 8.85 11.30 -2.66 -2.17 Coefficient of thermal expansion (10 ^-7 /℃) :300-600℃ -0.20 -6.84 10.18 15.70 -0.56 -0.19 Temperature at which the coefficient of thermal expansion rises rapidly 800-805 800~810 810-820 800~810 840~845 835~840

As can be seen from Table 1 above, it was found that in the case of Production Examples 4 and 5, the "temperature at which the coefficient of thermal expansion rises rapidly (above 20 x 10 ^-7 /°C)" is higher than in other cases. Preparation Examples 1 and 2 because it contains only one of Y ₂ O ₃ and Fe ₂ O _3, in the case of Production Example 3, the lack of the amount of Y ₂ O ₃ and Fe ₂ O ₃ set in the present invention hayeoteumeuro, respectively The temperature at which the coefficient of thermal expansion rises sharply was rather low. Therefore, in the present invention, it is preferable to use both Y ₂ O ₃ and Fe ₂ O ₃ in order to secure the stability of the thermal expansion coefficient of the LAS glass, and although not all expressed, the critical value of Y ₂ O ₃ is 0.1 ~ 1% by weight, Fe ₂ O _{3 It} was confirmed through experiments that the range of 0.2 to 1% by weight.

B. ZrSO ₄ To Effect when added

<Example 1>

This Example 1 is the same as <Production Example> in A. above except that Y ₂ O ₃ and Fe ₂ O ₃ are not added. Here, preferably, as a Zr-based compound, Zr(SO ₄ ) ₂ was used, and when Zr(SO ₄ ) ₂ is used, Zirconium sulfate hydrate has the advantages due to the light density and low melting point of ZOC. The precipitation phenomenon that can occur in the process is significantly reduced and uniformly grows into the glass interior to enable uniform crystal growth. In particular, it has the advantage that there is no concern about the generation of chlorine gas compared to ZOC.

To the glass, a clarifying agent for removing air bubbles is added. Most of the clarifying agents are in the form of polyvalent oxides, and among them, the representative form is SO ₄ oxide. In the present invention, since SnO ₂ was separately used as a clarifier, when Zr(SO ₄ ) ₂ is additionally used, the role of the clarifier is not intentionally added, but air bubbles together with the conventional clarifier In this respect, there is an advantage over using ZrO ₂ , ZrOCl ₂ , and ZrOSiO ₄ because the removal effect can be obtained.

<Example 2>

After preparing the mother glass in the same manner as in Example 1, the mother glass was heat treated at 720° C. for 3 hours, and then heat treated at 1100° C. for 3 hours to precipitate β-spodumene crystals to obtain crystallized glass. It was prepared.

<Comparative Example 1>

Β-quartz (β-quartz) crystallized glass was prepared under the same conditions as in Example 1, except that zirconium oxychloride or zirconyl chloride (ZrOCl ₂ ) was used as a nucleating agent. Zirconium oxychloride and zircon have a lower density and melting point than zirconia.

<Comparative Example 2>

After the mother glass was prepared in the same manner as in Comparative Example 1, the mother glass was heat treated at 720° C. for 3 hours, and then heat treated at 1100° C. for 3 hours to precipitate β-spodumene crystals to obtain crystallized glass. It was prepared.

<Comparative Example 3>

Β-quartz (β-quartz) crystallized glass was prepared under the same conditions as in Example 1, except that zircon (Zircon, Zr(SiO ₄ )) was used as a nucleating agent. Zirconium oxychloride and zircon have a lower density and melting point than zirconia.

<Comparative Example 4>

After the mother glass was prepared in the same manner as in Comparative Example 3, the mother glass was heat treated at 720°C for 3 hours, and then heat treated at 1100°C for 3 hours to precipitate β-spodumene crystals to obtain crystallized glass. It was prepared.

<Comparative Example 5>

Β-quartz (β-quartz) crystallized glass was prepared under the same conditions as in Example 1, except that zirconia was used as a nucleating agent. Zirconium oxychloride and zircon have a lower density and melting point than zirconia.

<Comparative Example 6>

After the mother glass was prepared in the same manner as in Comparative Example 5, the mother glass was heat treated at 720° C. for 3 hours, and then heat treated at 1100° C. for 3 hours to precipitate β-spodumene crystals to obtain crystallized glass. It was prepared.

The types of nucleating agents and crystal phases of Examples 1 and 2 and Comparative Examples 1 to 6 are summarized in Table 2.

Nucleating agent Crystal phase Example 1 Zr(SO ₄ ) ₂ β-quartz Example 2 Zr(SO ₄ ) ₂ β-spodumene Comparative Example 1 Zirconium oxychloride β-quartz Comparative Example 2 Zirconium oxychloride β-spodumene Comparative Example 3 zircon β-quartz Comparative Example 4 zircon β-spodumene Comparative Example 5 Zirconia β-quartz Comparative Example 6 Zirconia β-spodumene

<Test Example 1>

4 is a TMA analysis result of the mother glass made in the manufacturing process of the examples and comparative examples. (a) is a TMA analysis result of the parent glass of Examples 1 and 2 using Zr(SO ₄ ) ₂ as a nucleating agent, and (b) is a TMA analysis of the parent glass of Comparative Examples 1 and 2 using zirconium oxychloride as a nucleating agent. Results, (c) is the result of TMA analysis of the parent glass of Comparative Examples 3 and 4 using zircon as a nucleating agent, and (c) is the result of TMA analysis of the parent glass of Comparative Examples 5 and 6 using zirconia as a nucleating agent.

As can be seen in Figure 4, in the case of the parent glass of Examples 1 and 2, the coefficient of thermal expansion in the section between 0 and 600°C is similar to that of Comparative Examples 1 and 2, and the glass transition temperature and the softening temperature are 678°C, respectively. And 759°C, the glass transition temperature and softening temperature of the parent glass of Comparative Examples 1 and 2 were 707°C and 789°C, while the glass transition temperature and softening temperature of the parent glass of Comparative Examples 3 and 4 were 693°C and 786°C, etc. Although there are some differences, they can all be evaluated as commercially available levels.

<Test Example 2>

5 is a TMA analysis result of the embodiments and comparative examples of the present invention. (a) is the TMA analysis result of Example 1, (b) is the TMA analysis result of Example 2. (c) is the TMA analysis result of Comparative Example 1, (d) is the TMA analysis result of Comparative Example 3, and (e) is the TMA analysis result of Comparative Example 5. (f) is a TMA analysis result of Comparative Example 2, (g) is a TMA analysis result of Comparative Example 4, and (h) is a TMA analysis result of Comparative Example 6.

As can be seen from (c) to (e) of Figure 5, in the case of Example 1, Comparative Examples 1 and 3, it can be seen that the section near the coefficient of thermal expansion is increased by about 5 to 10 °C compared to Comparative Example 5. . In the case of Comparative Example 5, it shows a coefficient of thermal expansion close to 0 to about 848°C, but in the case of Example 1 and Comparative Example 1, it shows a coefficient of thermal expansion close to 0 to about 858°C, and in the case of Comparative Example 3, about 854°C It shows the coefficient of thermal expansion close to 0. This means that the crystallized glass of Example 1 and Comparative Example 1 is not broken by thermal shock even after water cooling after heating to about 858°C.

Here, the coefficient of thermal expansion refers to the change of the unit temperature and the unit length in a range of a temperature range. The term “thermal expansion coefficient is close to zero” means that the temperature is linear from room temperature to 850 degrees. It also means that the original length has been reached as shrinkage increases and shrinks. As an extreme example, even if it has a V-type thermal expansion curve, it can be zero.

When the glass heated to a high temperature is rapidly cooled, a tensile force is applied to the glass surface and a compressive force is applied to the inside of the glass due to a difference in thermal expansion coefficient between the glass surface and the inside. And if the difference between the two increases, the glass breaks. In the case of Example 1 and Comparative Example 1, since the coefficient of thermal expansion is close to 0 to about 858°C, tensile strength is not applied to the glass surface even after rapid cooling, so that it does not break.

In the β-quartz (β-quartz) crystallized glass, the temperature close to the thermal shock and the use temperature increase when the section with a coefficient of thermal expansion close to 0 rises to a section of high temperature, and thus Examples 1, Comparative Examples 1 and 3 are used in Comparative Example 5. It is advantageous compared to.

In addition, as can be seen from (f) to (h) of FIG. 5, Example 2, Comparative Examples 2 and 4 have a lower coefficient of thermal expansion than Comparative Example 6. This is because the size of the β-spodumene phase is fine and transitions at a higher temperature range.

<Test Example 3>

6 shows a photo crystallized with β-quartz solid solution by heat treatment at 860°C. If it was melted at 1650° C. using ZrO ₂ , it was partially confirmed that crystallization occurred non-uniformly as in FIG. 6( a ). ICP results in the glass with the ZrO ₂ ZrO ₂ content in the bottom was further observed that the presence of more than 1.49% measured at the top to 1.76%. Zirconia generally has a melting point of 2600°C or higher and a density of 6.0 cm 3 /g. Therefore, when melted at 1650°C, a number of cosmetic melts are observed in the platinum crucible and the glass. However, when the raw materials were used as ZOC and ZST, no unmelted melt was generated without stirring during melting, and as shown in Figs. 6(c) and (d), a uniform transparent crystallized glass was visually observed. Similar IrO ₂ content was measured in the upper and lower parts of the ICP result. These results show that the raw materials of ZOC and ZST have a melting point of 400°C or less, which is unlikely to be unmelted, unlike the ZrO _2, and the density is 1.9 and 2.1 g/cm3, respectively, and it is advantageous to uniformly distribute the ZrO ₂ level. , It is considered that more homogenization has progressed due to the release of Cl and S gas from the used raw material.

<Test Example 4>

7 is a SEM image for comparing the size and homogeneity of the crystal phase of the Examples and Comparative Examples of the present invention. Here, they were compared as β-spodumene pictures with distinct distinctions. FIG. 7(a) is the SEM photograph of Example 2, (b) is the SEM photograph of Comparative Example 2, (c) is the SEM photograph of Comparative Example 4, and (d) is the SEM photograph of Comparative Example 6. .

As can be seen from (a) to (d) of FIG. 7, it can be seen that when Zr(SO ₄ ) ₂ , zirconium oxychloride and zircon are used as a nucleating agent, crystals precipitated are finer and have higher homogeneity. The β-quartz (β-quartz) crystallized glass has an advantage that the finer the precipitated crystal, the better the transmittance of the crystallized glass. In this test, the mixing in the melting process was minimized to maximize the effect of the nucleating agent.

<Test Example 5>

Table 3 below summarizes the results of the ICP analysis in which the Zr content was measured by taking samples from the upper and lower layers of molten glass while varying the type of nucleating agent. As can be seen from Table 3, molten glass using Zr(SO ₄ ) ₂ , zirconium oxychloride or zircon as a nucleating agent is homogeneous compared to molten glass using zirconia.

Type of nucleating agent Upper floor substratum Zr(SO ₄ ) ₂ 1.79% 1.76% Zirconium oxychloride 1.85% 1.82% zircon 1.70% 1.80% Zirconia 1.49% 1.76%

In this test, mixing in the melting process was minimized in order to maximize the effect of the nucleating agent.

<Test Example 6>

Three-point bending strength was measured using the specimens of Example 1, Comparative Example 1, Comparative Example 3, and Comparative Example 5, and this is illustrated in FIG. 8. Here, in each of the examples, six samples were measured, and the average value and range were displayed. The crystallized glass specimen produced using zirconium oxychloride had a value of 171 MPa and showed the highest average value, and crystallization prepared using ZrO ₂ The glass had the lowest bending strength of 151 MPa. In particular, samples using ZrO ₂ and zircon had standard deviation values of 26 and 23 MPa, respectively, and exhibited a standard deviation value higher than twice that of glass produced using zirconium oxychloride and Zr(SO ₄ ) ₂ . Therefore, it is judged that the measurement error range of bending strength was observed to be small due to nucleation and growth due to more uniformly distributed ZrO ₂ such as using zirconium oxychloride and Zr(SO ₄ ) ₂ .

As described above, the present invention has been described through a preferred embodiment, but this is intended to help understanding of the technical content of the present invention and is not intended to limit the technical scope of the invention.

That is, a person having ordinary knowledge in the technical field to which the present invention pertains is capable of various modifications and modifications without departing from the technical gist of the present invention, and such changes or modifications are technical scope of the present invention in the interpretation of the claims. Of course it is within.

Claims (11)

Li ₂ O, Al ₂ O ₃ , SiO ₂ Mixing a raw material or a precursor for generating the raw material by heat treatment and an additive including Y ₂ O ₃ , Fe ₂ O ₃ and a Zr-based compound;
Preparing a melt by heating and melting the mixed raw material and additives;
Cooling the melt; And
Forming the cooled melt and then firing, or molding after firing;
Method for producing a crystallized glass of LAS (Li ₂ O-Al ₂ O ₃ -SiO ₂ ) containing Y ₂ O ₃ and Fe ₂ O ₃ , comprising: According to claim 1,
The Zr-based compound is a method for producing a crystallized glass of LAS (Li ₂ O-Al ₂ O ₃ -SiO ₂ ) containing Y ₂ O ₃ and Fe ₂ O ₃ , which is characterized in that Zr(SO ₄ ) ₂ . According to claim 2,
The Zr(SO ₄ ) ₂ is LAS (Li ₂ O-Al ₂ containing Y ₂ O ₃ and Fe ₂ O ₃ , characterized in that 1 to 2 parts by weight of ZrO ₂ is weighed and added based on the glass composition. Method for producing O ₃ -SiO ₂ )-based crystallized glass. According to claim 1,
The Y ₂ O ₃ and Fe ₂ O ₃ are LAS (Li) containing Y ₂ O ₃ and Fe ₂ O ₃ , each of which is added in an amount of more than 0 to 1 part by weight, and more than 0 to 0.2 part by weight, based on the glass composition. ₂ O-Al ₂ O ₃ -SiO ₂ ) Method for producing crystallized glass. According to claim 4,
When the Y ₂ O _3, Fe ₂ O ₃ was added simultaneously, Y ₂ O ₃ is 0.1 to 1 part by weight, Fe ₂ O ₃ is Y ₂ O ₃ and Fe ₂ characterized in that the addition of part 0.2 to 1 wt. O ₃ is contained LAS is _{(Li 2 O-Al 2 O} 3 -SiO 2) type method for producing a crystallized glass. According to claim 2,
When the Zr-based compound is Zr(SO ₄ ) ₂ , LAS (Li ₂ O-Al ₂ O ₃ -SiO containing Y ₂ O ₃ and Fe ₂ O ₃ , characterized in that the glass transition temperature is at least 855°C. ₂ ) Method for producing crystallized glass. LAS (Li ₂ O-Al ₂ O ₃ -SiO ₂ )-based crystallized glass,
And mixtures are added in the manufacturing process of the glass, the mixture is Y ₂ O ₃ and Fe LAS (Li ₂ that includes the Y ₂ O ₃ and Fe ₂ O _3, characterized in that the mixture of the ₂ O ₃ O-Al ₂ O ₃ -SiO ₂ ) based crystallized glass. The method of claim 7,
The Y ₂ O ₃ is added to 0 parts by weight or less based on the total composition of the glass, Fe ₂ O ₃ is more than 0 and 0.2 parts by weight or less, characterized in that Y ₂ O ₃ and Fe ₂ O ₃ containing LAS (Li ₂ O-Al ₂ O ₃ -SiO ₂ ) based crystallized glass. The method of claim 8,
When the Y ₂ O _3, Fe ₂ O ₃ was added simultaneously, Y ₂ O ₃ is 0.1 to 1 part by weight, Fe ₂ O ₃ is Y ₂ O ₃ and Fe ₂ characterized in that the addition of part 0.2 to 1 wt. LAS O ₃ is included is _{(Li 2 O-Al 2 O} 3 -SiO 2) based crystallized glass. According to claim 1,
The melting step is a LAS (Li ₂ O-Al ₂ O ₃ -SiO ₂ ) containing Y ₂ O ₃ and Fe ₂ O ₃ , which is characterized by heating and melting at 1550 to 1700°C for 2 to 4 hours. Crystallized glass. According to claim 1,
The cooling step is a LAS (Li containing Y ₂ O ₃ and Fe ₂ O ₃₎ characterized in that it is a step of cooling for 30 minutes to 1 hour and 30 minutes at a temperature of 10° C. to 25° C. higher than the glass transition temperature of the glass. ₂ O-Al ₂ O ₃ -SiO ₂ )-based crystallized glass.

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