Low thermal expansion component

Abstract

Provided is a low-thermal-expansion member which has a thermal expansion coefficient as low as that of conventional Li2O-Al2O3-SiO2-based crystallized glass and which is low in cost. The low thermal expansion member is characterized by containing a MgO-Al2O3-SiO2-based crystal.

Description

Technical Field

[0001] The present invention relates to a low thermal expansion component. Specifically, it relates to a component suitable as a material for, for example, front windows of kerosene stoves, wood-burning stoves, etc., substrates for high-tech products such as color filters and image sensor substrates, fixtures for firing electronic devices, light diffusion plates, furnace core tubes for semiconductor manufacturing, masks for semiconductor manufacturing, optical lenses, dimensional measurement components, communication components, building components, chemical reaction containers, top plates for electromagnetic cookers, heat-resistant tableware, heat-resistant covers, window glass for fireproof doors, components for astronomical telescopes, and components for space optics. Background Art

[0002] In the prior art, Li is used as a material for the front windows of kerosene stoves, wood stoves, etc., substrates for high-tech products such as color filters and image sensor substrates, fixtures for firing electronic devices, light diffusion plates, furnace core tubes for semiconductor manufacturing, masks for semiconductor manufacturing, optical lenses, dimensional measurement components, communication components, building components, chemical reaction containers, top plates for electromagnetic cookers, heat-resistant tableware, heat-resistant covers, window glass for fireproof doors, components for astronomical telescopes, and space optical components. 2 O-Al 2 O 3 -SiO 2 For example, Patent Documents 1 to 3 disclose that a β-quartz solid solution (Li 2 O.Al 2 O 3 nSiO 2 [where 2≤n≤4]) or β-spodumene solid solution (Li 2 O.Al 2 O 3 nSiO 2 [where n≥4]) etc. 2 O-Al 2 O 3 -SiO 2 Li 2 O-Al 2 O 3 -SiO 2 It is crystallized glass.

[0003] Li 2 O-Al 2 O 3 -SiO 2 The crystallized glass has a low thermal expansion coefficient and high mechanical strength, and thus has excellent thermal properties. In addition, by properly adjusting the heat treatment conditions in the crystallization process, the type of precipitated crystals can be controlled, and transparent crystallized glass (precipitated β-quartz solid solution) can be easily produced.

[0004] Prior art documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Publication No. 39-21049

[0007] Patent Document 2: Japanese Patent Publication No. 40-20182

[0008] Patent Document 3: Japanese Unexamined Patent Publication No. 1-308845

[0009] Patent Document 4: Japanese Unexamined Patent Publication No. 11-228180

[0010] Patent Document 5: Japanese Unexamined Patent Publication No. 11-228181 Summary of the invention

[0011] Technical problem to be solved by the invention

[0012] Recently, the development of lithium-ion batteries and the like has been in full swing, and the demand for lithium raw materials has increased dramatically in various industries, and the price of lithium raw materials has soared worldwide. As a result, it has become difficult to stably manufacture Li 2 O - Al 2 O 3 -SiO 2 -based crystallized glass, and therefore, a material capable of replacing the existing Li 2 O - Al 2 O 3 -SiO 2 -based crystallized glass is needed.

[0013] In view of the above circumstances, an object of the present invention is to provide a low thermal expansion member having a thermal expansion coefficient as low as that of the existing Li 2 O - Al 2 O 3 -SiO 2 -based crystallized glass and having a low cost.

[0014] Technical solution for solving the technical problem

[0015] The inventors of the present invention have conducted in-depth research and found that the above technical problem can be solved by using a member containing crystals having a specified composition, and thus a solution is proposed as the present invention.

[0016] [1] That is, the low thermal expansion member of the present invention is characterized by containing MgO - Al 2 O 3 -SiO 2 -based crystals. MgO - Al 2 O3 -SiO 2 The crystal of the -SiO system has low expansibility, and the main components are inexpensive MgO and Al 2 O 3 and SiO 2 , so the cost is low. Among them, in the present invention, "low thermal expansion" means that the thermal expansion coefficient at 30 to 380 °C is 30×10 -7 / °C or less.

[0017] [2] The low-thermal-expansion component of the present invention preferably contains α-cordierite (hexagonal cordierite) in the above [1] and has light transmittance. In this way, the component has light transmittance and it is easy to achieve low thermal expansion. Among them, "light transmittance" means that when the thickness is 4 mm, the transmittance (total light transmittance) at any wavelength of 380 nm, 800 nm, and 1200 nm is greater than 0%.

[0018] [3] The low-thermal-expansion component of the present invention preferably contains 20 to 90% of SiO 2 , more than 0 and 50% or less of Al 2 O 3 , and more than 0 and 40% or less of MgO by mass% in the above [1] or [2]. In this way, since the main components are inexpensive MgO, Al 2 O 3 and SiO 2 , the cost of the component is low and it is easy to achieve low thermal expansion.

[0019] [4] The low-thermal-expansion component of the present invention preferably has SiO 2 / (SiO 2 +Al 2 O 3 +MgO) of 0.45 to 0.81 by mass% in any one of the above [1] to [3]. In this way, the thermal expansion coefficient can be reduced and the light transmittance can be easily improved.

[0020] [5] The low-thermal-expansion component of the present invention preferably has Al 2 O 3 / (SiO 2 +Al 2 O 3 +MgO) of 0.01 to 0.45 by mass% in any one of the above [1] to [4]. In this way, the thermal expansion coefficient can be reduced and the light transmittance can be easily improved.

[0021] [6] The low-thermal-expansion component of the present invention preferably has MgO / (SiO 2 +Al 2 O 3The content of (MgO) is 0.03 to 0.29. In this way, the coefficient of thermal expansion can be reduced and the light transmittance can be easily increased.

[0022] [7] The low thermal expansion component of the present invention preferably contains SiO in mass % in any one of the above [1] to [6]. 2 / Al 2 O 3 The content is 1 to 15. In this way, the coefficient of thermal expansion can be reduced, the light transmittance can be increased, and the liquid phase viscosity can be easily increased.

[0023] [8] The low thermal expansion component of the present invention preferably contains SiO in mass % in any one of the above [1] to [7]. 2 / MgO is 2 to 15. In this way, the coefficient of thermal expansion can be reduced, the light transmittance can be increased, and the liquid phase viscosity can be easily increased.

[0024] [9] The low thermal expansion component of the present invention preferably contains Al in mass % in any one of the above [1] to [8]. 2 O 3 / MgO is 0.2 to 15. In this way, the coefficient of thermal expansion can be reduced, the light transmittance can be increased, and the liquid phase viscosity can be easily increased.

[0025]

[10] The low thermal expansion component of the present invention preferably contains BaO in the range of 0 to 5.6% in mass %, SiO in any one of the above [1] to [9]. 2 / Al 2 O 3 is 2.5 to 15, SiO 2 / MgO is 5.4 to 15. In this way, devitrification can be easily suppressed. Moreover, the coefficient of thermal expansion can be reduced, the light transmittance can be increased, and the liquid phase viscosity can be easily increased.

[0026]

[11] The low thermal expansion component of the present invention preferably contains BaO in the range of 0 to 5.6% in mass %, SiO in any one of the above [1] to

[10] . 2 / Al 2 O 3 is 2.5 to 15, Al 2 O 3 / MgO is 1.8 to 15. In this way, devitrification can be easily suppressed. Moreover, the coefficient of thermal expansion can be reduced, the light transmittance can be increased, and the liquid phase viscosity can be easily increased.

[0027]

[12] The low thermal expansion component of the present invention preferably contains SiO in the range of 55.5 to 90% in mass %, and ZnO is greater than 0%. In this way, the coefficient of thermal expansion can be reduced and the formability and meltability of the glass can be easily improved. 2 The content is 55.5 to 90%, and ZnO is greater than 0%. In this way, the coefficient of thermal expansion can be reduced and the formability and meltability of the glass can be easily improved.

[0028]

[13] The low thermal expansion component of the present invention preferably has (Li 2 O + Na 2 O + K 2 O) / SiO 2 of 0.00005 to 0.03 in terms of mass% in any one of the above [1] to

[12] . In this way, the viscosity characteristics of the glass can be optimized, the precipitation of crystals can be promoted efficiently, and the chemical durability can be easily improved.

[0029]

[14] The low thermal expansion component of the present invention preferably has Li 2 O + Na 2 O + K 2 O + CaO + SrO + BaO of 2% or less in terms of mass% in any one of the above [1] to

[13] . In this way, cloudiness is less likely to occur.

[0030]

[15] The low thermal expansion component of the present invention preferably has (SiO 2 + ZnO) / (MgO + Al 2 O 3 ) of 0.7 to 3 in terms of mass% in any one of the above [1] to

[14] . In this way, the thermal expansion coefficient can be reduced and the light transmittance can be easily improved.

[0031]

[16] The low thermal expansion component of the present invention preferably has ZnO - (TiO 2 + ZrO 2 ) of -15 to 5% in terms of mass% in any one of the above [1] to

[15] . In this way, the light transmittance can be easily improved.

[0032]

[17] The low thermal expansion component of the present invention preferably has TiO 2 / (TiO 2 + Fe 2 O 3 ) of 0.001 to 0.999 in terms of mass% in any one of the above [1] to

[16] . In this way, a low thermal expansion component with high light transmittance can be easily obtained at low cost.

[0033]

[18] The low thermal expansion component of the present invention preferably contains MoO 3 , V 2 O 5 , CuO, NiO, MnO 2 , Cr 2 O 3 , Nd 2 O 3 , WO 3 , Co 3 O 4One or more of the above. In this way, it is easy to promote the precipitation of crystals. And it is easy to color the glass into the desired color.

[0034]

[19] The low thermal expansion component of the present invention preferably contains MoO in a mass percentage greater than 0% in any one of the above [1] to

[18] . 3 . In this way, the viscosity of the glass can be reduced and the meltability and formability of the glass can be easily improved.

[0035]

[20] The low thermal expansion component of the present invention preferably has SiO in a mass percentage in any one of the above [1] to

[19] . 2 / (SiO 2 + Al 2 O 3 + MgO) is 0.36 to 0.81, Al 2 O 3 / (SiO 2 + Al 2 O 3 + MgO) is 0.09 to 0.5, MgO / (SiO 2 + Al 2 O 3 + MgO) is 0.01 to 0.29, Na 2 O is 0.01% or more and less than 2.5%, and contains at least one of As 2 O 3 , Sb 2 O 3 , SnO 2 , Cl. In this way, the thermal expansion coefficient can be reduced and the light transmittance can be easily improved.

[0036]

[21] The low thermal expansion component of the present invention preferably has a β - OH value greater than 0 and 2 / mm or less in any one of the above [1] to

[20] . In this way, the initial reaction of the raw material batch can be promoted, and the bubble quality and heat resistance of the component can be easily improved, etc.

[0037]

[22] The low thermal expansion component of the present invention preferably has a transmittance of 10% or more at a thickness of 4 mm and a wavelength of 1200 nm in any one of the above [1] to

[21] . In this way, it is particularly suitable for infrared communication applications such as infrared cameras or remote controls, etc. Here, in this specification, when simply referred to as "transmittance", it means "total light transmittance", which is different from diffuse transmittance.

[0038]

[23] The low thermal expansion component of the present invention preferably has a thermal expansion coefficient of 30×10 -7 / °C or less at 30 to 380 °C in any one of the above [1] to

[22] . In this way, it is suitable for various applications requiring low thermal expansion characteristics.

[0039]

[24] The low thermal expansion component of the present invention preferably has a thermal expansion coefficient of 30×10 -7 / °C or less at 30 to 750°C in any one of the above [1] to

[23] . In this way, it is suitable for various applications that require low thermal expansion characteristics.

[0040]

[25] The low thermal expansion component of the present invention is preferably devitrified glass in any one of the above [1] to

[24] . In this way, it is easy to fabricate a component having desired characteristics. Here, devitrified glass refers to a composite material containing glass and crystals obtained by subjecting the original glass (crystalline glass) in a glass state before crystallization to heat treatment or the like to precipitate desired crystals in the glass matrix.

[0041]

[26] The precursor of the low thermal expansion component of the present invention is characterized in that it is formed of crystalline glass, and the crystalline glass contains, by mass%, 20 to 90% of SiO 2 , more than 0 and 50% or less of Al 2 O 3 , more than 0 and 40% or less of MgO, 0 to 20% of CaO, 0 to 20% of SrO, 0 to 20% of BaO, 0 to 20% of ZnO, 0 to 10% of Li 2 O, 0 to 20% of Na 2 O, 0 to 20% of K 2 O, 0 to 20% of B 2 O 3 , 0 to 20% of P 2 O 5 , 0 to 20% of TiO 2 , 0 to 20% of ZrO 2 , 0 to 10% of HfO 2 , 0 to 20% of SnO 2 .

[0042]

[27] The manufacturing method of the low thermal expansion component of the present invention is the manufacturing method of the low thermal expansion component of the above

[25] , and is characterized by including: a step of heating and melting raw materials and then molding them to obtain crystalline glass; and a step of heat-treating the above crystalline glass to crystallize it.

[0043]

[28] In the manufacturing method of the low thermal expansion component of the present invention, it is preferable that the addition amount of metallic Al in the raw materials in the above

[27] is more than 0 and 5000 ppm or less by mass%. In this way, it is easy to promote the crystallization of the glass.

[0044] Advantages of the Invention

[0045] According to the present invention, it is possible to provide a thermal expansion coefficient such as that of the existing Li2 O-Al 2 O 3 -SiO 2 is a low-thermal-expansion component as low and low-cost as the O-Al-O-SiO-based crystallized glass. Description of the Drawings

[0046] Figure 1 It is a diagram showing the XRD spectrum of Example No. 127.

[0047] Figure 2 It is a histogram showing the measurement results of the pore size of Example No. 306. Detailed Description of the Invention

[0048] The low-thermal-expansion component of the present invention is characterized by containing MgO-Al 2 O 3 -SiO 2 system crystal. As the MgO-Al 2 O 3 -SiO 2 system crystal, specifically preferably α-cordierite. α-Cordierite is represented by Mg 2 Al 4 Si 5 O 18 and is a crystal having a hexagonal crystal structure. It is known that α-cordierite shows negative expansion with respect to the c-axis of the crystal. If α-cordierite is included, the coefficient of thermal expansion is likely to approach zero, and since the main components are inexpensive MgO, Al 2 O 3 and SiO 2 , it is easy to achieve low cost. The low-thermal-expansion component of the present invention may also contain cordierite other than α-cordierite. For example, μ-cordierite which is a metastable phase having the same hexagonal crystal structure as α-cordierite and β-cordierite having an orthorhombic crystal structure. And, as long as the low-thermal-expansion component of the present invention can obtain the desired characteristics (that is, the desired low-thermal-expansion characteristics and translucency), it may also contain crystals other than the MgO-Al 2 O 3 -SiO 2 system crystal. As such crystals, for example, zinc spinel, willemite (zinc silicate), Al 2 SiO 5(aluminum silicate), zirconia, zirconium titanate, tin-containing zirconia-based oxides, titanium dioxide, aluminum titanate, β-quartz solid solution, α-quartz, β-quartz, β-spodumene solid solution, spodumene, zircon, enstatite, mica, nepheline, anorthite, lithium disilicate, lithium metasilicate, wollastonite, diopside, cristobalite, tridymite, feldspar, spinel-based crystals, metal colloids, etc. These crystals may contain only one kind or two or more kinds.

[0049] The low thermal expansion component of the present invention is composed of, for example, crystallized glass. And the crystallized glass of the present invention may be crystallized glass in which crystals are precipitated from the surface of the glass or crystallized glass in which crystals are precipitated from the inside other than the surface, as long as it has the desired properties. As the composition of the crystallized glass, for example, it preferably contains 20 to 90% of SiO 2 , more than 0 and 50% or less of Al 2 O 3 , more than 0 and 40% or less of MgO. The reasons for limiting the composition as described above are as follows. Herein, in the following description of the content of each component, unless otherwise specified, "%" means "mass%".

[0050] SiO 2 forms the glass skeleton and constitutes MgO-Al 2 O 3 -SiO 2 -based crystal components. The content of SiO 2 is preferably 90% or less, 80% or less, 75% or less, 73% or less, 70% or less, particularly 69% or less, and preferably 20% or more, 30% or more, 35% or more, 40% or more, 45% or more, 48% or more, 50% or more, 53% or more, 55.5 or more, particularly 57% or more. When the content of SiO 2 is too small, there is a tendency for the thermal expansion coefficient to increase, and it is difficult to obtain crystallized glass with excellent thermal shock resistance. There is also a tendency for chemical durability to decrease. And the liquid-phase viscosity of the glass is also likely to decrease, making it difficult to form the glass and reducing the productivity. Therefore, when emphasizing the improvement of the liquid-phase viscosity of the glass, the lower limit of the content of SiO 2 is preferably 58% or more, 60% or more, 61% or more, 62% or more, 63% or more, 65% or more, particularly 67% or more. On the other hand, in SiO 2When the content is excessive, the fusibility of the glass decreases, or the viscosity of the glass melt increases, making it difficult to clarify, or the glass is difficult to form, and the productivity is likely to decrease. In addition, the time required for crystallization is prolonged, and the productivity is likely to decrease. There is also a tendency to precipitate crystals other than the desired crystals such as α-cordierite (e.g., quartz crystals, etc.), and the thermal expansion coefficient of the crystallized glass is likely to increase.

[0051] Al 2 O 3 is a component of the MgO-Al 2 O 3 -SiO 2 system crystal. The content of Al 2 O 3 is preferably greater than 0 and 50% or less, 1-47.5%, 5-45%, 10-42.5%, 12-40%, 13-37.5%, 15-35%, 15-30%, especially 16-25%. When the content of Al 2 O 3 is too small, it is difficult to precipitate the desired crystals such as α-cordierite. As a result, there is a tendency for the thermal expansion coefficient to increase. Moreover, the difference in thermal expansion coefficient between the crystallized phase and the remaining glass phase after crystallization increases, so the crystallized glass is sometimes prone to breakage. Also, the difference in refractive index between the crystallized phase and the remaining glass phase after crystallization increases, and the crystallized glass is likely to become opaque. On the other hand, when the content of Al 2 O 3 is excessive, the viscosity of the glass melt becomes too low, and it becomes difficult to form the glass. As a result, the productivity is likely to decrease. In addition, precipitating crystals such as mullite will cause devitrification of the glass, and the crystallized glass becomes prone to breakage.

[0052] MgO is a component of the MgO-Al 2 O 3 -SiO 2 system crystal. The content of MgO is preferably greater than 0 and 40% or less, 1-37.5%, 2-35%, 3-32.5%, 4-30%, 5-27.5%, 6-25%, 7-20%, especially 7-15%. When the content of MgO is too small, it is difficult to precipitate the desired crystals such as α-cordierite. As a result, there is a tendency for the thermal expansion coefficient to increase. Moreover, the difference in thermal expansion coefficient between the crystallized phase and the remaining glass phase after crystallization increases, so the crystallized glass is sometimes prone to breakage. Also, the difference in refractive index between the crystallized phase and the remaining glass phase after crystallization increases, and the crystallized glass is likely to become opaque. On the other hand, when the content of MgO is excessive, the viscosity of the glass melt becomes too low, and it becomes difficult to form the glass. As a result, the productivity is likely to decrease.

[0053] In the low thermal expansion component of the present invention, the desired low thermal expansion characteristics are achieved by MgO-Al2 O 3 -SiO 2 The negative expansion of the crystalline phase composed of crystals such as (especially α-cordierite crystals) and the positive expansion of the remaining glass phase cancel each other out. Moreover, the light transmittance can be improved by adjusting the refractive index difference between the above-mentioned crystalline phase and the remaining glass phase. That is, in order to obtain a crystallized glass with high light transmittance and low thermal expansion, it is preferable to strictly adjust the elemental composition of the crystalline phase and the remaining glass phase in the crystallized glass, the proportion of their existence, etc. Through in-depth research, the inventors of the present invention found that by respectively specifying the content ratios of MgO, SiO 2 and Al 2 O 3 which constitute the crystalline phase, the crystalline phase and the remaining glass phase can be appropriately controlled. The ratio of SiO 2 / (SiO 2 +Al 2 O 3 (the content of SiO 2 to the total content of SiO 2 , Al 2 O 3 and MgO) is preferably 0.99 or less, 0.9 or less, 0.81 or less, 0.78 or less, 0.75 or less, especially 0.73 or less, and is preferably 0.18 or more, 0.2 or more, 0.25 or more, 0.3 or more, 0.35 or more, 0.36 or more, 0.4 or more, 0.45 or more, especially 0.5 or more. And the ratio of Al 2 O 3 / (SiO 2 +Al 2 O 3 (the content of Al 2 O 3 to the total content of SiO 2 , Al 2 O 3 and MgO) is preferably 0.71 or less, 0.6 or less, 0.5 or less, 0.45 or less, 0.4 or less, 0.3 or less, especially 0.25 or less, and is preferably 0.01 or more, 0.09 or more, 0.13 or more, 0.14 or more, 0.15 or more, 0.16 or more, 0.17 or more, especially 0.18 or more. And the ratio of MgO / (SiO 2 +Al 2 O 3 +MgO) (the content of MgO to the total content of SiO 2 , Al 2 O 3The ratio of the total content of (with MgO) is preferably 0.67 or less, 0.6 or less, 0.5 or less, 0.4 or less, 0.29 or less, 0.2 or less, 0.15 or less, 0.125 or less, particularly 0.1 or less. And it is preferably 0.01 or more, 0.03 or more, 0.04 or more, 0.05 or more, 0.06 or more, particularly 0.07 or more. SiO 2 / (SiO 2 +Al 2 O 3 +MgO), Al 2 O 3 / (SiO 2 +Al 2 O 3 +MgO), MgO / (SiO 2 +Al 2 O 3 +MgO) are outside the above ranges respectively, it is difficult to precipitate crystals such as α-cordierite, and there is a tendency for the thermal expansion coefficient of the obtained crystallized glass to increase. Also, the refractive index difference between the crystal phase and the remaining glass phase increases, and the crystallized glass tends to become opaque.

[0054] In the low thermal expansion component of the present invention, it is found that regarding the contents of MgO, SiO 2 and Al 2 O 3 of the crystal phase components, by respectively specifying the ratio of the content of SiO 2 / Al 2 O 3 (the ratio of the content of SiO 2 to the content of Al 2 O 3 ), SiO 2 / MgO (the ratio of the content of SiO 2 to the content of MgO), Al 2 O 3 / MgO (the ratio of the content of Al 2 O 3 to the content of MgO) as described below, it is possible to achieve a crystallized glass with high light transmittance and low thermal expansion, and the liquid-phase viscosity increases, so the glass is easy to mold and the productivity is improved. SiO 2 / Al 2 O 3 is preferably 20 or less, 15 or less, 10 or less, 7.5 or less, 7 or less, 6.5 or less, 6 or less, 5.5 or less, 5 or less, 4.5 or less, 4 or less, particularly 3.75 or less, and is preferably 0.4 or more, 0.5 or more, 1 or more, 1.2 or more, 1.4 or more, 1.5 or more, 1.7 or more, 2 or more, 2.5 or more, particularly 3 or more. In addition, SiO 2 / MgO is preferably 20 or less, 15 or less, 14 or less, 13 or less, 12 or less, 11.5 or less, 11 or less, 10.5 or less, 10 or less, 9.5 or less, particularly 9 or less, and preferably 0.5 or more, 2 or more, 2.4 or more, 2.8 or more, 3 or more, 3.4 or more, 3.5 or more, 4 or more, 5 or more, 5.4 or more, 6 or more, 7 or more, particularly 8 or more. Additionally, Al 2 O 3 / MgO is preferably 15 or less, 10 or less, 5 or less, 4.8 or less, 4.6 or less, 4.4 or less, 4.2 or less, 4 or less, 3.8 or less, 3.6 or less, 3.4 or less, 3.2 or less, particularly 3 or less, and preferably 0.05 or more, 0.1 or more, 0.2 or more, 0.4 or more, 0.6 or more, 0.8 or more, 1 or more, 1.2 or more, 1.4 or more, 1.6 or more, 1.8 or more, 2 or more, particularly 2.3 or more. SiO 2 / Al 2 O 3 、SiO 2 / MgO、Al 2 O 3 / MgO are outside the above ranges respectively, it is difficult to precipitate crystals such as α-cordierite, and there is a tendency for the thermal expansion coefficient of the obtained crystallized glass to increase. Moreover, the refractive index difference between the crystal phase and the remaining glass phase increases, and the crystallized glass tends to become opaque. Also, due to the decrease in the liquid-phase viscosity, the glass forming becomes difficult and the productivity decreases.

[0055] In addition to containing the above components, the low thermal expansion component of the present invention may further contain 0 to 10% of Li 2 O, 0 to 20% of Na 2 O, 0 to 20% of K 2 O, 0 to 20% of CaO, 0 to 20% of SrO, 0 to 20% of BaO, 0 to 20% of ZnO, 0 to 20% of B 2 O 3 、0 to 20% of P 2 O 5 、0 to 20% of TiO 2 、0 to 20% of ZrO 2 、0 to 20% of SnO 2 。

[0056] Li 2 O can be solid-dissolved in MgO - Al 2 O 3 - SiO 2The components of the system crystal are components that can largely affect crystallinity, reduce the viscosity of the glass, and improve the meltability and formability of the glass. On the other hand, as mentioned above, due to the soaring price of lithium raw materials worldwide, it is necessary to reduce the Li content as much as possible. 2 O content. In addition, when the content of Li 2 O is too high, the thermal expansion coefficient becomes too large, and it is difficult to improve heat resistance and thermal shock resistance. Therefore, the content of Li 2 O is preferably 0 to 10%, 0 to 8%, 0 to 6%, 0 to 4%, 0 to 3%, 0 to 2.5%, 0 to 2%, 0 to 1.5%, 0 to 1%, 0 to 0.5%, 0 to 0.3%, 0 to 0.2%, 0 to 0.1%, especially 0 to 0.05%. However, Li 2 O is easily mixed in as an impurity. Therefore, if Li 2 O is completely removed, the price of the raw material batch will increase, and there is a tendency for the manufacturing cost to increase. When suppressing the increase in manufacturing cost, the lower limit of the content of Li 2 O is preferably 0.0001% or more, 0.0003% or more, especially 0.0005% or more.

[0057] Na 2 O is a component that can reduce the viscosity of the glass and improve the meltability and formability of the glass. It is also a component used to adjust the thermal expansion coefficient and refractive index of MgO-Al 2 O 3 -SiO 2 -based crystallized glass. The content of Na 2 O is preferably 20% or less, 15% or less, 10% or less, 5% or less, 3% or less, less than 2.5%, 1.5% or less, less than 1.5%, 1% or less, 0.5% or less, especially 0.3% or less. When the content of Na 2 O is too high, it is likely to devitrify and the glass is likely to break. However, Na 2 O is easily mixed in as an impurity. Therefore, if Na 2 O is completely removed, the price of the raw material batch will increase, and there is a tendency for the manufacturing cost to increase. When suppressing the increase in manufacturing cost, the lower limit of the content of Na 2 O is preferably 0.0001% or more, 0.0003% or more, 0.0005% or more, 0.001 or more, 0.003 or more, 0.005 or more, especially 0.01 or more.

[0058] K 2 O is a component that can reduce the viscosity of the glass and improve the meltability and formability of the glass. It is also a component used to adjust the thermal expansion coefficient and refractive index of MgO-Al 2 O 3 -SiO 2Components such as the coefficient of thermal expansion and refractive index of the crystallized glass. K 2 The content of K 2 O is preferably 0 to 20%, 0 to 15%, 0 to 10%, 0 to 5%, 0 to 3%, 0 to 1%, 0 to 0.5%, particularly 0 to 0.3%. When the content of K 2 O is excessive, devitrification is likely to occur and the glass is easily damaged. However, K 2 O is easily mixed in as an impurity. Therefore, if K 2 O is completely removed, the price of the raw material batch will increase, and there is a tendency for the manufacturing cost to increase. When suppressing the increase in manufacturing cost, the lower limit of the content of K

[0059] Li 2 O, Na 2 O, K 2 O are components that improve the meltability and formability of the glass. However, when the content of these components is excessive, it may cause the viscosity to decrease excessively and the glass to soften excessively during crystallization. And when the content of Li 2 O, Na 2 O, K 2 O is excessive, the chemical durability of the glass decreases. On the other hand, SiO 2 is a component that constitutes the MgO - Al 2 O 3 -SiO 2 system crystal, and by containing an appropriate amount, it has the effect of increasing the viscosity of the glass and suppressing the softening of the remaining glass. It is also a component that improves the chemical durability of the glass. Therefore, in order to optimize the viscosity characteristics of the glass, efficiently promote the precipitation of crystals, and obtain a crystallized glass with high chemical durability, it is preferable to control (Li 2 O + Na 2 O + K 2 O) / SiO 2 (the ratio of the total content of Li 2 O, Na 2 O and K 2 O to the content of SiO 2 ) within a preferred range. (Li 2 O + Na 2 O + K 2 O) / SiO 2 is preferably 0 to 0.1, 0.00005 to 0.03, 0.00005 to 0.01, 0.0001 to 0.008, 0.0002 to 0.007, 0.0003 to 0.006, 0.0004 to 0.005, particularly 0.0004 to 0.002.

[0060] CaO is a component that can reduce the viscosity of glass and improve the meltability and formability of glass. It is also a component used to adjust the thermal expansion coefficient, refractive index, etc. of MgO-Al 2 O 3 -SiO 2 -system crystallized glass. The content of CaO is preferably 0 to 20%, 0 to 15%, 0 to 10%, 0 to 5%, 0 to 3%, 0 to 1%, 0 to 0.5%, especially 0 to 0.3%. When the content of CaO is excessive, devitrification is likely to occur and the glass is easily damaged. However, CaO is easily mixed in as an impurity. Therefore, if CaO is completely removed, the price of the raw material batch will increase, and there is a tendency for the manufacturing cost to increase. When suppressing the increase in manufacturing cost, the lower limit of the content of CaO is preferably 0.0001% or more, 0.0003% or more, especially 0.0005% or more.

[0061] SrO is a component that can reduce the viscosity of glass and improve the meltability and formability of glass. It is also a component used to adjust the thermal expansion coefficient, refractive index, etc. of MgO-Al 2 O 3 -SiO 2 -system crystallized glass. The content of SrO is preferably 0 to 20%, 0 to 15%, 0 to 10%, 0 to 5%, 0 to 3%, 0 to 1%, 0 to 0.5%, especially 0 to 0.3%. When the content of SrO is excessive, devitrification is likely to occur and the glass is easily damaged. However, SrO is easily mixed in as an impurity. Therefore, if SrO is completely removed, the price of the raw material batch will increase, and there is a tendency for the manufacturing cost to increase. When suppressing the increase in manufacturing cost, the lower limit of the content of SrO is preferably 0.0001% or more, 0.0003% or more, especially 0.0005% or more.

[0062] BaO is a component that can reduce the viscosity of glass and improve the meltability and formability of glass. It is also a component used to adjust the thermal expansion coefficient, refractive index, etc. of MgO-Al 2 O 3 -SiO 2 -system crystallized glass. The content of BaO is preferably 0 to 20%, 0 to 15%, 0 to 10%, 0 to 7%, 0 to 6%, 0 to 5.6%, 0 to 5%, 0 to 4%, 0 to 3%, 0 to 1%, 0 to 0.5%, especially 0 to 0.3%. When the content of BaO is excessive, devitrification is likely to occur and the glass is easily damaged. However, BaO is easily mixed in as an impurity. Therefore, if BaO is completely removed, the price of the raw material batch will increase, and there is a tendency for the manufacturing cost to increase. When suppressing the increase in manufacturing cost, the lower limit of the content of BaO is preferably 0.0001% or more, 0.0003% or more, especially 0.0005% or more.

[0063] In the low thermal expansion component of the present invention, Li 2 O, Na 2 O, K 2 O, CaO, SrO, and BaO cations are more likely to remain in the residual glass phase after crystallization than Mg cations that form the main crystal. Therefore, when their total content is excessive, sometimes a refractive index difference is likely to occur between the crystal phase and the residual glass, and the crystallized glass is likely to become cloudy. Therefore, Li 2 O + Na 2 O + K 2 O + CaO + SrO + BaO (total content of Li 2 O, Na 2 O, K 2 O, CaO, SrO, and BaO) is preferably 9% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, 1% or less, 0.8% or less, 0.5% or less, and particularly 0.3% or less.

[0064] ZnO is a component that can reduce the viscosity of the glass and improve the meltability and formability of the glass. It is also a component used to adjust the thermal expansion coefficient, refractive index, etc. of MgO - Al 2 O 3 -SiO 2 -based crystallized glass. The content of ZnO is preferably 0 - 20%, 0 - 15%, 0 - 10%, more than 0 and 5% or less, 0.1 - 5%, 0.2 - 4%, 0.3 - 3.5%, 0.4 - 3%, 0.5 - 2.5%, 0.6 - 2%, 0.7 - 1.9%, and particularly 0.8 - 1.8%. When the content of ZnO is excessive, devitrification is likely to occur and the glass is likely to break. In addition, if the refractive index difference between the crystal phase and the glass phase increases, the obtained crystallized glass is likely to become cloudy. By actively containing ZnO, the refractive index difference between the crystal phase and the glass phase decreases, and cloudiness of the crystallized glass is easily suppressed.

[0065] In the low thermal expansion component of the present invention, (SiO 2 +ZnO) / (MgO + Al 2 O 3 )(ratio of the total content of SiO 2 and ZnO to the total content of MgO and Al 2 O 3 ) is preferably 0.5 - 5, 0.7 - 3, 0.8 - 2.8, 0.9 - 2.7, 1 - 2.7, and particularly 1.2 - 2.7. (SiO 2 +ZnO) / (MgO + Al 2 O 3)When it is above the above upper limit value, it is difficult to precipitate α-cordierite crystals, and there is a tendency for the thermal expansion coefficient of the obtained crystallized glass to increase. On the other hand, when it is below the above lower limit value, there is a tendency for the liquidus temperature of the glass to easily increase, and thus devitrification is likely to occur during manufacturing.

[0066] B 2 O 3 is a component that can reduce the viscosity of the glass and improve the meltability and formability of the glass. B 2 O 3 The content is preferably 0 to 20%, 0 to 15%, 0 to 10%, 0 to 5%, 0.1 to 5%, 0.2 to 3%, especially 0.2 to 1%. When the content of B 2 O 3 is excessive, the evaporation amount of B 2 O 3 increases during melting, and the environmental burden increases. There is also a tendency for surface crystallization to proceed excessively, the mechanical strength of the obtained crystallized glass is likely to decrease, and the desired light transmittance may not be achieved. However, B 2 O 3 is easily mixed in as an impurity. Therefore, if B 2 O 3 is to be completely removed, the price of the raw material batch will increase, and there is a tendency for the manufacturing cost to increase. When suppressing the increase in manufacturing cost, B 2 O 3 can contain 0.0001% or more, 0.0003% or more, especially 0.0005% or more.

[0067] P 2 O 5 is a component that can reduce the viscosity of the glass and improve the meltability and formability of the glass. On the other hand, when the content of P 2 O 5 is excessive, the precipitation amount of MgO - Al 2 O 3 -SiO 2 system crystals decreases, and there is a tendency for the thermal expansion coefficient of the obtained crystallized glass to increase. The content of P 2 O 5 is preferably 0 to 20%, 0 to 15%, 0 to 10%, 0 to 5%, especially 0 to 3%. However, P 2 O 5 is easily mixed in as an impurity. Therefore, if P 2 O 5 is to be completely removed, the price of the raw material batch will increase, and there is a tendency for the manufacturing cost to increase. When suppressing the increase in manufacturing cost, P 2 O 5It may contain 0.0001% or more, 0.0003% or more, 0.0005% or more, 0.001% or more, 0.005% or more, 0.01% or more, 0.05% or more, particularly 0.1% or more.

[0068] TiO 2 is a component that can reduce the viscosity of the glass and improve the meltability and formability of the glass. It is also a component that promotes crystallization, and can cause good precipitation of MgO-Al 2 O 3 -SiO 2 system crystals, achieve the desired low thermal expansion characteristics and contribute to the improvement of light transmittance. On the other hand, when contained in a large amount, it may cause the precipitated crystals to grow, and there is a possibility of reduced light transmittance. It will also significantly enhance the coloring of the glass. Especially when zirconium titanate crystals containing ZrO 2 and TiO 2 are precipitated, in these crystals, electrons transition from the valence electron band of oxygen as a ligand to the conduction bands of zirconium oxide and titanium as the central metals (LMCT transition), participating in the coloring of the crystallized glass. In addition, when titanium remains in the residual glass phase, LMCT transition occurs from the valence electron band of the SiO 2 skeleton to the conduction band of tetravalent titanium in the residual glass phase. And d-d transition occurs in trivalent titanium in the residual glass phase, participating in the coloring of the crystallized glass. In addition, when titanium and iron coexist, coloring similar to ilmenite (FeTiO 3 ) appears. It is also known that yellow is enhanced when titanium and tin coexist. Therefore, the content of TiO 2 is preferably 20% or less, 15% or less, 10% or less, 8% or less, 5% or less, particularly 4% or less, and is also preferably greater than 0%, 0.005% or more, 0.01% or more, 0.1% or more, 1% or more, 2% or more, 2.5% or more, 3% or more, particularly 3.3% or more. And, according to the use of the low thermal expansion component of the present invention, the content of TiO 2 can also be controlled and the light transmittance can be adjusted. For example, when a colored (e.g., black) appearance is required in a top plate for a cooker, etc., the content of TiO 2 can be set to 4% or more.

[0069] ZrO 2 is a component that promotes crystallization. When the content is excessive, large ZrO 2 crystals are precipitated, and the crystallized glass is likely to devitrify or break. Therefore, the content of ZrO 2 is preferably 20% or less, 15% or less, 10% or less, 5% or less, 3% or less, particularly 1% or less. On the other hand, by adding an appropriate amount, the precipitation of MgO-Al 2 O3 -SiO 2 system crystal's microcrystalline size and precipitation amount, thus contributing to achieving the desired low thermal expansion property and enhancing light transmittance. Therefore, when using ZrO 2 to obtain the above effects, the content of ZrO 2 is preferably greater than 0%, 0.005% or more, 0.01% or more, 0.1% or more, 1% or more, 2% or more, especially 3.3% or more.

[0070] In the crystallized glass, by reducing the refractive index difference between the crystalline phase and the residual glass phase, the light scattering is reduced and its light transmittance can be enhanced. In the MgO - Al 2 O 3 -SiO 2 system crystallized glass, ZnO is a component that adjusts the refractive index of the residual glass. On the other hand, TiO 2 and ZrO 2 are components that can play the role of crystal nuclei, and can promote the precipitation of crystals and thus affect the refractive index of the crystalline phase. Therefore, in order to further enhance the light transmittance of the low thermal expansion component of the present invention, it is preferable to appropriately control the content of these components. Specifically, the content of ZnO - (TiO 2 +ZrO 2 )(the difference between the content of ZnO and the total content of TiO 2 and ZrO 2 ) is preferably -15 to 5%, -10 to 4%, -5 to 3%, especially -5 to 2%.

[0071] HfO 2 is a component that enhances the Young's modulus and rigidity modulus of the glass, and is also a component that can reduce the viscosity of the glass and enhance the meltability and formability of the glass. When the content of HfO 2 is excessive, the mechanical strength of the obtained crystallized glass becomes too high, processing etc. become difficult, and it is difficult to obtain an appropriate surface state and excellent light transmittance. Also, the price of the HfO 2 raw material is high, thus resulting in an increase in manufacturing cost. Therefore, the content of HfO 2 is preferably 10% or less, 5% or less, 1% or less, 0.5% or less, 0.3% or less, 0.1% or less, especially 0.05% or less. Additionally, the lower limit of the content of HfO 2 is 0% or more and is not particularly limited, but HfO 2 is a component that can be mixed in from the raw materials used, and its mixing amount varies depending on the raw material composition. Therefore, HfO 2 can actually contain 0.0001% or more, 0.0003% or more, especially 0.0005% or more.

[0072] SnO 2 The reaction of SnO 2 →SnO + 1 / 2O 2 occurs at high temperatures, releasing O 2 gas in the glass melt. It is known that this reaction is the clarification mechanism of SnO 2 . The O 2 gas released during the reaction not only has a "defoaming effect" of enlarging the tiny bubbles existing in the glass melt and releasing them to the glass system, but also has a "stirring effect" of mixing the glass melt. In addition, in the low thermal expansion component of the present invention, it is also a component that promotes crystallization. By containing an appropriate amount, it is easy to obtain a crystallized glass having the desired light transmittance and thermal expansion coefficient. On the other hand, when contained in a large amount, it is a component that significantly enhances the coloring of the glass, and at the same time, the devitrification tendency is likely to increase. The upper limit value of the content of SnO 2 is preferably 20% or less, 15% or less, 10% or less, 5% or less, 3% or less, 1% or less, 0.5% or less, particularly 0.3% or less, and the lower limit value is preferably greater than 0%, 0.005% or more, 0.01% or more, 0.05% or more, particularly 0.1% or more. However, SnO 2 is easily mixed as an impurity. Therefore, if SnO 2 is to be completely removed, the price of the raw material batch will increase, and there is a tendency for the manufacturing cost to increase. Therefore, by specifying the lower limit value of the content of SnO 2 as described above, the increase in manufacturing cost can also be suppressed.

[0073] In addition to containing the above components, the low thermal expansion component of the present invention may also contain the following components.

[0074] Fe 2 O 3 is a component that enhances the coloring of the glass. Especially through the interaction with TiO 2 or SnO 2 , it is also a component that significantly enhances the coloring. The content of Fe 2 O 3 is preferably 0.4% or less, 0.1% or less, 0.08% or less, 0.06% or less, 0.05% or less, 0.04% or less, 0.035% or less, 0.03% or less, 0.02% or less, 0.015% or less, 0.013% or less, 0.012% or less, particularly 0.011% or less. However, Fe 2 O 3 is easily mixed as an impurity. Therefore, if Fe 2 O 3 is to be completely removed, the price of the raw material batch will increase, and there is a tendency for the manufacturing cost to increase. In order to suppress the increase in manufacturing cost, Fe 2 O3 The lower limit of the content is preferably 0.0001% or more, 0.0002% or more, 0.0003% or more, 0.0005% or more, particularly 0.001% or more. Also, according to the use of the low thermal expansion member of the present invention, the content of Fe 2 O 3 can be controlled and the light transmittance can be adjusted. For example, when a colored appearance is required in a top plate for a cooker or the like, the content of Fe 2 O 3 can be set to 0.1% or more, 0.3% or more, particularly 1% or more.

[0075] In the case where titanium and iron coexist, coloring similar to ilmenite (FeTiO 3 ) may occur. Particularly, in the case where MgO - Al 2 O 3 -SiO 2 -based crystallized glass contains titanium and iron, the components of titanium and iron that are not precipitated as crystal nuclei or main crystals after crystallization remain in the remaining glass, promoting the occurrence of the above coloring. The amount of these components can be reduced in design, but TiO 2 and Fe 2 O 3 are easily mixed as impurities. Therefore, if they are completely removed, the price of the raw material batch will increase, and there is a tendency for the manufacturing cost to increase. Therefore, from the viewpoint of suppressing the coloring of the obtained crystallized glass, it is preferable that TiO 2 / (TiO 2 +Fe 2 O 3 ) is 0 to 1. On the other hand, in order to make the manufacturing cost cheaper, these two components can also be contained within the allowable coloring range. In such a case, TiO 2 / (TiO 2 +Fe 2 O 3 ) is preferably 0.001 to 0.999, 0.003 to 0.997, 0.005 to 0.995, 0.007 to 0.993, 0.009 to 0.991, 0.01 to 0.99, 0.1 to 0.9, 0.15 to 0.85, 0.2 to 0.8, particularly 0.25 to 0.75. In this way, it is easy to inexpensively obtain a low thermal expansion member with high light transmittance.

[0076] As 2 O 3 The reaction As 2 O 5 →As 2 O 3 +O 2 occurs at high temperature, and O is released in the glass melt2 gas. It is known that this reaction is the clarification mechanism of As 2 O 3 . The O 2 gas released during the reaction has a "defoaming effect" of increasing the tiny bubbles existing in the glass melt and releasing them outside the glass system. On the other hand, when it is contained in a large amount, since As 2 O 3 is a toxic component, there is a possibility of environmental pollution during the glass manufacturing process or the treatment of waste glass, etc. The content of As 2 O 3 is preferably 0 to 20%, 0 to 5%, 0 to 1%, especially 0 to 0.1%. However, As 2 O 3 is easily mixed as an impurity. Therefore, if As 2 O 3 is to be completely removed, the price of the raw material batch will increase, and there is a tendency for the manufacturing cost to increase. In order to suppress the increase in the manufacturing cost, the lower limit of the content of As 2 O 3 is preferably 0.0003% or more, 0.0005% or more, 0.001% or more, 0.005% or more, 0.01% or more, especially 0.02% or more.

[0077] Sb 2 O 3 undergoes the reaction of Sb 2 O 5 →Sb 2 O 3 +O 2 in the high temperature, and O 2 gas is released in the glass melt. It is known that this reaction is the clarification mechanism of Sb 2 O 3 . The O 2 gas released during the reaction has a "defoaming effect" of increasing the tiny bubbles existing in the glass melt and releasing them outside the glass system. On the other hand, when it is contained in a large amount, since Sb 2 O 3 is a toxic component, there is a possibility of environmental pollution during the glass manufacturing process or the treatment of waste glass, etc. The content of Sb 2 O 3 is preferably 0 to 20%, 0 to 5%, 0 to 1%, especially 0 to 0.1%. However, Sb 2 O 3 is easily mixed as an impurity. Therefore, if Sb 2 O 3 is to be completely removed, the price of the raw material batch will increase, and there is a tendency for the manufacturing cost to increase. In order to suppress the increase in the manufacturing cost, Sb 2O 3 The lower limit of the content of [substance] is preferably 0.0003% or more, 0.0005% or more, 0.001% or more, 0.005% or more, 0.01% or more, particularly 0.02% or more.

[0078] Cl 2 At high temperatures, the reaction NaCl → NaCl gas occurs, and NaCl gas is released in the glass melt. It is known that this reaction is the clarification mechanism of Cl 2 The NaCl gas released during the reaction has a "defoaming effect" of enlarging the minute bubbles present in the glass melt and releasing them outside the glass system. On the other hand, when present in large amounts, since Cl 2 is a toxic component, there is a possibility of environmental pollution during the glass manufacturing process or the treatment of waste glass, etc. The content of Cl 2 is preferably 0 - 20%, 0 - 5%, 0 - 1%, particularly 0 - 0.1%. On the other hand, if Cl 2 is completely removed, the price of the raw material batch will increase, and there is a tendency for the manufacturing cost to increase. To suppress the increase in manufacturing cost, the lower limit of the content of Cl 2 is preferably 0.0003% or more, 0.0005% or more, 0.001% or more, 0.005% or more, 0.01% or more, particularly 0.02% or more.

[0079] As 2 O 3 and Sb 2 O 3 are toxic components, so when present in large amounts, there is a possibility of environmental pollution during the glass manufacturing process or the treatment of waste glass, etc. Therefore, As 2 O 3 +Sb 2 O 3 (The total content of As 2 O 3 and Sb 2 O 3 The upper limit value of the total content) is preferably 20% or less, 5% or less, 1% or less, 0.5% or less, particularly less than 0.3%. On the other hand, these components act as fining agents in the glass melt and have a "defoaming effect" of enlarging the minute bubbles present in the glass melt and releasing them outside the glass system. Therefore, when improving the bubble elimination property of the glass, As 2 O 3 +Sb 2 O 3The lower limit of the content can be greater than 0, can be 0.0003% or more, 0.0005% or more, 0.001% or more, 0.005% or more, 0.01% or more, 0.05% or more, particularly 0.1% or more.

[0080] SnO 2 , As 2 O 3 , Sb 2 O 3 , Cl 2 is toxic. Therefore, when contained in large amounts, there is a possibility of environmental pollution during the glass manufacturing process or the treatment of waste glass, etc. Thus, SnO 2 + As 2 O 3 + Sb 2 O 3 + Cl 2 (the total content of SnO 2 , As 2 O 3 , Sb 2 O 3 , Cl 2 ) preferably has an upper limit of 20% or less, 5% or less, 1% or less, 0.3% or less, particularly 0.2% or less. On the other hand, these components play a role as fining agents in the glass melt, having a "defoaming effect" of enlarging the minute bubbles present in the glass melt and releasing them to the outside of the glass system. Therefore, when improving the bubble elimination property of the glass, it is preferable to contain at least one of SnO 2 , As 2 O 3 , Sb 2 O 3 , Cl 2 . The lower limit of the content of SnO 2 + As 2 O 3 + Sb 2 O 3 + Cl 2 can be greater than 0, can be 0.0003% or more, 0.0005% or more, 0.001% or more, 0.005% or more, 0.01% or more, 0.05% or more, particularly 0.1% or more.

[0081] SnO 2 not only has a fining effect but also has an effect of promoting crystallization. And, the toxicity of SnO 2 is lower than that of As 2 which has the same fining effect as SnO 2 O 3 , Sb 2 O 3and Cl 2 is low, so it is not easy to pollute the environment. Therefore, in order to have a low environmental burden, improve the bubble elimination property of the glass, promote the crystallization of the glass, and effectively obtain the desired properties, in SnO 2 , As 2 O 3 , Sb 2 O 3 and Cl 2 Among these components with a clarifying effect, it is preferably actively contained SnO 2 , SnO 2 / (As 2 O 3 +Sb 2 O 3 +SnO 2 +Cl 2 )(the content ratio of SnO 2 to the total content of SnO 2 , As 2 O 3 , Sb 2 O 3 , Cl 2 ) preferably has a lower limit value of 0.00003 or more, 0.0003 or more, 0.003 or more, 0.03 or more, 0.05 or more, 0.1 or more, 0.5 or more. And the upper limit value is not particularly limited, and in reality it is 10% or less.

[0082] Pt is a component that can be mixed into glass in the form of ions, colloids, metals, etc., presenting a yellow to brownish color. Moreover, this tendency becomes more pronounced after crystallization. The inventors of the present invention conducted further in-depth research and concluded that once Pt is mixed in, the nucleation and crystallization behavior of the crystallized glass will be affected, and sometimes cloudiness is likely to occur. Therefore, the content of Pt is preferably 60 ppm or less, 30 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1.6 ppm or less, 1.4 ppm or less, 1.2 ppm or less, 1 ppm or less, 0.9 ppm or less, 0.8 ppm or less, 0.7 ppm or less, 0.6 ppm or less, 0.5 ppm or less, 0.45 ppm or less, 0.40 ppm or less, 0.35 ppm or less, and particularly 0.30 ppm or less. Although the mixing of Pt should be avoided as much as possible, in the case of using ordinary melting equipment, in order to obtain homogeneous glass, Pt components sometimes have to be used. Therefore, if Pt is to be completely removed, there is a tendency for the manufacturing cost to increase. Without adversely affecting the coloring, in order to suppress the increase in manufacturing cost, the lower limit of the content of Pt is preferably 0.0001 ppm or more, 0.001 ppm or more, 0.005 ppm or more, 0.01 ppm or more, 0.02 ppm or more, 0.03 ppm or more, 0.04 ppm or more, 0.05 ppm or more, 0.06 ppm or more, and particularly 0.07 ppm or more. In addition, when coloring is allowed, Pt can be used as a crystallization promoter. At this time, Pt can be used alone or in combination with other components. In addition, when Pt is used as a crystallization promoter, its form is not particularly limited (colloid, metal crystal, etc.).

[0083] Rh is a component that can be mixed into glass in the form of ions, colloids, metals, etc. It shows the same yellow to brownish - tea coloring as Pt and has a tendency to cause cloudiness in crystallized glass. Therefore, the content of Rh is preferably 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1.6 ppm or less, 1.4 ppm or less, 1.2 ppm or less, 1 ppm or less, 0.9 ppm or less, 0.8 ppm or less, 0.7 ppm or less, 0.6 ppm or less, 0.5 ppm or less, 0.45 ppm or less, 0.40 ppm or less, 0.35 ppm or less, especially 0.30 ppm or less. Although the incorporation of Rh should be avoided as much as possible, in the case of using ordinary melting equipment, in order to obtain homogeneous glass, it is sometimes necessary to use Rh components. Therefore, if Rh is to be completely removed, there is a tendency for the manufacturing cost to increase. Without adversely affecting the coloring, in order to suppress the increase in manufacturing cost, the lower limit of the content of Rh is preferably 0.0001 ppm or more, 0.001 ppm or more, 0.005 ppm or more, 0.01 ppm or more, 0.02 ppm or more, 0.03 ppm or more, 0.04 ppm or more, 0.05 ppm or more, 0.06 ppm or more, especially 0.07 ppm or more. In addition, in the case where coloring is allowed, Rh can be used as a crystallization accelerator. At this time, Rh can be used alone or in combination with other components. In addition, when Rh is used as a crystallization accelerator, the form of Rh is not particularly limited (colloid, metal crystal, etc.).

[0084] In addition, the total amount of Pt + Rh (the combined amount of Pt and Rh) is preferably 60 ppm or less, 30 ppm or less, 9 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4.75 ppm or less, 4.5 ppm or less, 4.25 ppm or less, 4 ppm or less, 3.75 ppm or less, 3.5 ppm or less, 3.25 ppm or less, 3 ppm or less, 2.75 ppm or less, 2.5 ppm or less, 2.25 ppm or less, 2 ppm or less, 1.75 ppm or less, 1.5 ppm or less, 1.25 ppm or less, 1 ppm or less, 0.95 ppm or less, 0.9 ppm or less, 0.85 ppm or less, 0.8 ppm or less, 0.75 ppm or less, 0.7 ppm or less, 0.65 ppm or less, 0.60 ppm or less, 0.55 ppm or less, 0.50 ppm or less, 0.45 ppm or less, 0.40 ppm or less, 0.35 ppm or less, particularly 0.30 ppm or less. In addition, although the incorporation of Pt and Rh should be avoided as much as possible, in the case of using a conventional melting apparatus, in order to obtain homogeneous glass, it is sometimes necessary to use Pt and Rh components. Therefore, if Pt and Rh are completely removed, there is a tendency for the manufacturing cost to increase. Without adversely affecting the coloring, in order to suppress the increase in the manufacturing cost, the lower limit of Pt + Rh is preferably 0.0001 ppm or more, 0.001 ppm or more, 0.005 ppm or more, 0.01 ppm or more, 0.02 ppm or more, 0.03 ppm or more, 0.04 ppm or more, 0.05 ppm or more, 0.06 ppm or more, particularly 0.07 ppm or more.

[0085] MoO 3 is a component that can reduce the viscosity of the glass and improve the meltability and formability of the glass. MoO 3 content is preferably 0% or more, greater than 0%, particularly 0.0001% or more. On the other hand, when the MoO 3 content is excessive, the glass is colored or devitrified substances containing Mo are precipitated, which easily leads to an increase in the manufacturing burden. Therefore, the MoO 3 content is preferably 20% or less, 15% or less, 10% or less, 5% or less, particularly 3% or less. Also, according to the use of the low thermal expansion member of the present invention, the MoO 3 content can be controlled and the light transmittance can be adjusted. For example, in the case of a colored appearance being required for a top plate for a cooker, etc., the MoO 3 content can be set to 0.01% or more, 0.1% or more, 0.3% or more, particularly 0.5% or more.

[0086] V 2 O5 , CuO, NiO, MnO 2 , Cr 2 O 3 , Nd 2 O 3 , WO 3 , Co 3 O 4 are components that can color the low thermal expansion parts. Therefore, according to the use of the low thermal expansion parts of the present invention, the above components can also be contained to adjust the light transmittance of the low thermal expansion parts. For example, when a colored appearance is required in a top plate for a cooker, etc., the content of the above components can be set to be greater than 0 and 5% or less, 0.01 - 4%, 0.05 - 3.5%, especially 0.1 - 3% or more, respectively.

[0087] When the low thermal expansion parts of the present invention want to obtain the desired characteristics, as long as there is no adverse effect, for the purpose of promoting crystallization or coloring the low thermal expansion parts and endowing other functions, in addition to containing the above components, it can also contain, for example, H with a content of 0.1% or less respectively 2 , CO 2 , CO, H 2 O, He, Ne, Ar, N 2 and other trace components.

[0088] When Ag, Au, Pd, Ir, Sc, Ce, Pr, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ac, Th, Pa, U, etc. are intentionally added to the glass, the raw material cost increases, and there is a tendency for the manufacturing cost to increase. On the other hand, when the glass containing Ag or Au, etc. is irradiated with light or heat-treated, aggregates of these components can be formed, and crystallization can be promoted starting from them. And Pd, etc. have various catalytic effects, and by containing them, specific functions can be imparted to the crystallized glass. In view of such a situation, for the purpose of promoting crystallization or coloring the low thermal expansion parts and endowing other functions, the above components can be contained in the range of 1% or less, 0.5% or less, 0.3% or less, 0.1% or less respectively, otherwise preferably 500 ppm or less, 300 ppm or less, 100 ppm or less, especially 10 ppm or less.

[0089] When further desired characteristics are to be obtained, as long as there is no adverse effect, the low thermal expansion parts of the present invention can contain a total amount of 10% or less of SO 3 , MnO, Y 2 O 3 , La 2 O 3 , HfO 2 , Ta 2 O5 , Nb 2 O 5 , RfO 2 etc. However, the raw material batch of the above components has a high price and there is a tendency for the manufacturing cost to increase. Therefore, it may not be added when there is no special situation.

[0090] In view of the above situation, regarding the preferred composition range of the low thermal expansion component of the present invention, in mass %, it is SiO 2 0 - 70%, Al 2 O 3 10 - 50%, MgO 3 - 40%, Li 2 O 0 - 10%, Na 2 O 0 - 20%, K 2 O 0 - 20%, CaO 0 - 20%, SrO 0 - 20%, BaO 0 - 20%, ZnO 0 - 20%, B 2 O 3 0 - 20%, P 2 O 5 0 - 20%, TiO 2 0 - 20%, ZrO 2 0 - 20%, SnO 2 0 - 20%, Fe 2 O 3 0.1% or less, Pt 7 ppm or less, Rh 7 ppm or less, Pt + Rh 9 ppm, MoO 3 greater than 0%, and the other preferred composition range is BaO 0 - 5.6%, SiO 2 / Al 2 O 3 2.5 - 15, SiO 2 / MgO 5.4 - 15, or BaO 0 - 5.6%, SiO 2 / Al 2 O 3 2.5 - 15, Al 2 O 3 / MgO 1.8 - 15, or SiO 2 55.5 - 90%, ZnO greater than 0%.

[0091] In addition, the precursor of the low thermal expansion component of the present invention is constituted by, for example, crystalline glass (the original glass before crystallization). At this time, the content range of each component of the crystalline glass is the same as above. In addition, for example, by heat-treating the precursor of the low thermal expansion component under specified conditions, a low thermal expansion component can be obtained.

[0092] The β-OH value of the low thermal expansion component of the present invention is preferably greater than 0 and 2 / mm or less, 0.001 - 2 / mm, 0.01 - 1.5 / mm, 0.02 - 1.5 / mm, 0.03 - 1.2 / mm, 0.04 - 1.5 / mm, 0.05 - 1.4 / mm, 0.06 - 1.3 / mm, 0.07 - 1.2 / mm, 0.08 - 1.1 / mm, 0.08 - 1 / mm, 0.08 - 0.9 / mm, 0.08 - 0.85 / mm, 0.08 - 0.8 / mm, 0.08 - 0.75 / mm, 0.08 - 0.74 / mm, 0.08 - 0.73 / mm, 0.08 - 0.72 / mm, 0.08 - 0.71 / mm, and particularly 0.08 - 0.7 / mm. When the β-OH value is within the above range, the quality of the glass is not easily deteriorated. That is, when the β-OH value is too small, the amount of water vapor generated when melting the raw material batch is reduced. Therefore, the stirring effect of the raw material batch due to the generation of water vapor is weakened, the initial reaction of the raw material batch is difficult to be promoted, and the manufacturing load is likely to increase. On the other hand, when the β-OH value is too large, bubbles are likely to be generated at the interface between metal components such as Pt and refractory components and the glass melt, and the quality of the obtained glass component is likely to deteriorate. It may also cause a decrease in the glass transition temperature, yield point, strain point, annealing point, softening point, or an increase in the thermal expansion coefficient, and deterioration of heat resistance and thermal shock resistance, and thus it is not suitable for use at high temperatures.

[0093] The density of the low thermal expansion component of the present invention is preferably 1.2 - 3.50 g / cm 3 , 2.00 - 3.40 g / cm 3 , 2.10 - 3.35 g / cm 3 , 2.20 - 3.30 g / cm 3 , and particularly 2.30 - 3.25 g / cm 3 . When the density is too small, it may cause an increase in the gas permeability of the glass and contamination of the glass during long-term storage. On the other hand, when the density is too large, the weight per unit area increases and the operation becomes difficult.

[0094] The transmittance (total light transmittance) of the low thermal expansion component of the present invention at a thickness of 4 mm and a wavelength of 380 nm is preferably 0.5% or more, 1% or more, 3% or more, 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 78% or more, 80% or more, 81% or more, 82% or more, 83% or more, particularly 84% or more. When the transmittance at a wavelength of 380 nm is too low, the yellow coloring is enhanced and the transparency of the component is reduced, and the desired transmission performance may not be obtained. In addition, depending on the application, even if the transmittance at a wavelength of 380 nm is low, there may sometimes be no problem. In this case, the transmittance at a wavelength of 380 nm is not limited to the above range and may be less than 0.5%.

[0095] The transmittance (total light transmittance) of the low thermal expansion component of the present invention at a thickness of 4 mm and a wavelength of 800 nm is preferably 0.5% or more, 1% or more, 3% or more, 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 78% or more, 80% or more, 81% or more, 82% or more, 83% or more, 84% or more, 85% or more, 86% or more, 87% or more, particularly 88% or more. When the transmittance at a wavelength of 800 nm is too low, the appearance is likely to show green. Particularly when used in medical applications such as vein authentication, etc., a high transmittance at a wavelength of 800 nm is preferred. In addition, depending on the application, even if the transmittance at a wavelength of 800 nm is low, there may sometimes be no problem. In this case, the transmittance at a wavelength of 800 nm is not limited to the above range and may be less than 0.5%.

[0096] The transmittance (total light transmittance) of the low thermal expansion component of the present invention at a thickness of 4 mm and a wavelength of 1200 nm is preferably 0.5% or more, 1% or more, 3% or more, 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 81% or more, 82% or more, 83% or more, 84% or more, 85% or more, 86% or more, 87% or more, 88% or more, particularly 89% or more. Particularly, when used in infrared communication applications such as infrared cameras or remote controls, etc., a high transmittance at a wavelength of 1200 nm is preferred. Additionally, depending on the application, even if the transmittance at a wavelength of 1200 nm is low, there may sometimes be no problem. In this case, the transmittance at a wavelength of 1200 nm is not limited to the above range and can be less than 0.5%.

[0097] The liquidus temperature of the low thermal expansion component of the present invention is preferably 1540 °C or lower, 1535 °C or lower, 1530 °C or lower, 1525 °C or lower, 1520 °C or lower, 1515 °C or lower, 1510 °C or lower, 1505 °C or lower, 1500 °C or lower, 1495 °C or lower, 1490 °C or lower, 1485 °C or lower, 1480 °C or lower, 1475 °C or lower, 1470 °C or lower, 1465 °C or lower, 1460 °C or lower, 1455 °C or lower, 1450 °C or lower, 1445 °C or lower, 1440 °C or lower, 1435 °C or lower, 1430 °C or lower, 1425 °C or lower, 1420 °C or lower, 1415 °C or lower, particularly 1410 °C. When the liquidus temperature is too high, devitrification is likely to occur during manufacturing. On the other hand, when it is 1480 °C or lower, manufacturing using a roll method, etc. is easy; when it is 1450 °C or lower, manufacturing using a casting method, etc. is easy; when it is 1410 °C or lower, manufacturing using a melting method, etc. is easy.

[0098] The liquid-phase viscosity (logarithm of the viscosity corresponding to the liquid-phase temperature) of the low thermal expansion component of the present invention is preferably 1.6 or more, 1.70 or more, 1.75 or more, 1.80 or more, 1.85 or more, 1.90 or more, 1.95 or more, 2.00 or more, 2.05 or more, 2.10 or more, 2.15 or more, 2.20 or more, 2.25 or more, 2.30 or more, 2.35 or more, 2.40 or more, 2.45 or more, 2.50 or more, 2.55 or more, 2.60 or more, 2.65 or more, 2.70 or more, 2.75 or more, 2.80 or more, 2.85 or more, 2.90 or more, 2.95 or more, 3.00 or more, 3.05 or more, 3.10 or more, 3.15 or more, 3.20 or more, 3.25 or more, 3.30 or more, 3.35 or more, 3.40 or more, 3.45 or more, 3.50 or more, 3.55 or more, 3.60 or more, 3.65 or more, particularly 3.70 or more. When the liquid-phase viscosity is too low, devitrification is likely to occur during manufacturing. On the other hand, when it is 3.40 or more, manufacturing using the roll method or the like is easy; when it is 3.50 or more, manufacturing using the casting method or the like is easy; when it is 3.70 or more, manufacturing using the melting method or the like is easy.

[0099] The thermal expansion coefficient of the low thermal expansion component of the present invention at 30 to 380 °C is preferably 30×10 -7 / °C or less, 25×10 -7 / °C or less, 20×10 -7 / °C or less, 18×10 -7 / °C or less, 16×10 -7 / °C or less, 14×10 -7 / °C or less, 13×10 -7 / °C or less, 12×10 -7 / °C or less, 11×10 -7 / °C or less, 10×10 -7 / °C or less, 9×10 -7 / °C or less, 8×10 -7 / °C or less, 7×10 -7 / °C or less, 6×10 -7 / °C or less, 5×10 -7 / °C or less, 4×10 -7 / °C or less, 3×10 -7 / °C or less, particularly 2×10 -7 / °C or less. Among them, in cases where dimensional stability and / or thermal shock resistance are particularly required, it is preferably -5×10 -7 / °C to 5×10 -7 / °C, -3×10 -7 / °C to 3×10 -7 / °C, -2.5×10-7 / °C to 2.5×10 -7 / °C, -2×10 -7 / °C to 2×10 -7 / °C, -1.5×10 -7 / °C to 1.5×10 -7 / °C, -1×10 -7 / °C to 1×10 -7 / °C, especially -0.5×10 -7 / °C to 0.5×10 -7 / °C.

[0100] The low thermal expansion component of the present invention preferably has a thermal expansion coefficient of 30×10 -7 / °C or less, 25×10 -7 / °C or less, 20×10 -7 / °C or less, 18×10 -7 / °C or less, 16×10 -7 / °C or less, 14×10 -7 / °C or less, 13×10 -7 / °C or less, 12×10 -7 / °C or less, 11×10 -7 / °C or less, 10×10 -7 / °C or less, 9×10 -7 / °C or less, 8×10 -7 / °C or less, 7×10 -7 / °C or less, 6×10 -7 / °C or less, 5×10 -7 / °C or less, 4×10 -7 / °C or less, especially 3×10 -7 / °C or less. Among them, in cases where dimensional stability and / or thermal shock resistance are particularly required, it is preferably -15×10 -7 / °C to 15×10 -7 / °C, -12×10 -7 / °C to 12×10 -7 / °C, -10×10 -7 / °C to 10×10 -7 / °C, -8×10 -7 / °C to 8×10 -7 / °C, -6×10 -7 / °C to 6×10 -7 / °C, -5×10 -7 / °C to 5×10 -7 / °C, -4.5×10 -7 / °C to 4.5×10 -7 / °C, -4×10 -7 / °C to 4×10 -7 / °C, -3.5×10 -7 / °C to 3.5×10 -7 / °C, -3×10 -7 / °C to 3×10 -7 / °C, -2.5×10 -7 / °C to 2.5×10 -7 / °C, -2×10 -7 / °C to 2×10 -7 / °C, -1.5×10 -7 / °C to 1.5×10 -7 / °C, -1×10 -7 / °C to 1×10 -7 / °C, especially -0.5×10 -7 / °C to 0.5×10 -7 / °C.

[0101] The low thermal expansion component of the present invention can be chemically strengthened, etc. Regarding the treatment conditions of the chemical strengthening treatment, the treatment time and treatment temperature can be appropriately selected in consideration of the glass composition, crystallinity, type of molten salt, etc. For example, in order to facilitate chemical strengthening after crystallization, a glass composition containing a large amount of Na 2 O that can be contained in the remaining glass can be selected, or the crystallinity can be intentionally reduced. In addition, alkali metals such as Li, Na, and K in the molten salt can be contained alone or in combination. Also, not only can the usual one-step strengthening be selected, but also multi-step chemical strengthening can be selected. In addition, physical strengthening such as air-cooling strengthening can also be implemented. Moreover, a film can be attached to the surface by sputtering, etc., and at this time, the physical durability and chemical durability can be improved.

[0102] Next, a method for manufacturing the low thermal expansion component of the present invention will be described.

[0103] First, the raw material batch prepared to form the glass of the above composition is put into a glass melting furnace and melted at 1600 to 1700°C and then formed. Thus, a crystalline glass (glass before crystallization), which is a precursor, is obtained. Among them, when melting the glass, a flame melting method using a burner, etc., an electric melting method using electric heating, etc. can be adopted. In addition, melting using laser irradiation or melting using plasma can also be adopted. And the sample shape can be made into a plate shape, a fiber shape, a film shape, a powder shape, a spherical shape, a hollow shape, etc., without particular limitation.

[0104] When manufacturing the low thermal expansion component of the present invention, metallic Al can be added to the raw material batch. In the present invention, metallic Al is a component that can promote the crystallization of glass and also a component that adjusts the refractive index of the remaining glass phase and improves the light transmittance of the obtained crystallized glass. On the other hand, when excessive, it may cause cloudiness in the crystallized glass. The addition amount of metallic Al is preferably greater than 0 and 5000 ppm or less, 1 to 4000 ppm, particularly 10 to 3000 ppm.

[0105] As a method for forming molten glass, there can be mentioned the overflow method, the floating method, the down-draw method, the slot down-draw method, the redraw method, the containerless method, the blowing method, the pressing method, the roll method, the sleeve method, the tube drawing method, etc.

[0106] Next, the obtained crystalline glass is heat-treated to crystallize it. As the crystallization conditions, it is maintained at 800 to 1250 °C for 2 minutes to 1000 hours. Among them, the heat treatment can be carried out only at a specific temperature, or it can be carried out stepwise while maintaining at two or more temperature levels, or heating can be carried out while applying a temperature gradient. In addition, crystallization can also be promoted by applying or irradiating sound waves or electromagnetic waves.

[0107] Next, the heat-treated glass is cooled. The cooling rate of the glass can be carried out at a specific temperature gradient or at two or more temperature gradients. When sufficient thermal shock resistance is desired, it is desirable to control the cooling rate and sufficiently perform the structural relaxation of the remaining glass phase. Regarding the average cooling rate from 800 °C to 25 °C, in the part of the thickness (wall thickness) center farther from the outermost surface of the crystallized glass, it is preferably 3000 °C / min or less, 1000 °C / min or less, 500 °C / min or less, 400 °C / min or less, 300 °C / min or less, 200 °C / min or less, 100 °C / min or less, 50 °C / min or less, 25 °C / min or less, 10 °C / min or less, particularly 5 °C / min or less. In addition, when long-term dimensional stability is desired, it is preferably 2.5 °C / min or less, 1 °C / min or less, 0.5 °C / min or less, 0.1 °C / min or less, 0.05 °C / min or less, 0.01 °C / min or less, 0.005 °C / min or less, 0.001 °C / min or less, 0.0005 °C / min or less, particularly 0.0001 °C / min or less. Except in the case of physical strengthening treatment using air cooling, water cooling, etc., it is preferable that the cooling rate at the surface of the glass is similar to the cooling rate at the thickness center part farthest from the surface. The value obtained by dividing the cooling rate at the thickness center part farthest from the glass surface by the cooling rate at the glass surface is preferably 0.0001 to 1, 0.001 to 1, 0.01 to 1, 0.1 to 1, 0.5 to 1, 0.8 to 1, 0.9 to 1, particularly 1. The closer this value is to 1, the less likely it is for residual strain to occur in each part of the glass sample, and the easier it is to obtain long-term dimensional stability. Among them, the cooling rate at the glass surface can be estimated using a contact thermometer or a radiation thermometer, and the temperature inside the glass can be estimated by immersing the glass sample in a high-temperature state in a cooling medium, measuring the heat and heat change rate of the cooling medium, and based on this numerical data and the specific heat and thermal conductivity of the glass sample and the cooling medium, etc.

[0108] When the low thermal expansion component of the present invention is plate-shaped, the average surface roughness Ra of its main surface is preferably 50 nm or less, 25 nm or less, 15 nm or less, 10 nm or less, 9 nm or less, 8 nm or less, 7 nm or less, 6 nm or less, 5 nm or less, 4 nm or less, 3 nm or less, 2 nm or less, and particularly 1 nm or less. When the surface roughness Ra is too large, the light incident on the glass surface from the outside is easily scattered, and it is difficult for the light to exit from the inside of the glass to the outside of the glass, making it difficult to obtain the desired light transmittance. Moreover, the glass is easily damaged. On the other hand, when the surface roughness Ra of the plane is too small, the glass surface is easily charged, and the gravitational force between the glass and the object in contact with the glass surface increases, and sometimes it is difficult to obtain the demolding property. In addition, due to the charging of the glass surface, it is sometimes difficult to obtain the desired electrical responsiveness. In view of the above, the surface roughness Ra of the plane of the glass of the present invention is preferably 0.01 nm or more, 0.03 nm or more, 0.05 nm or more, 0.07 nm or more, 0.09 nm or more, 0.1 nm or more, 0.3 nm or more, and particularly 0.5 nm or more.

[0109] In addition, when the low thermal expansion component of the present invention is plate-shaped, the average surface roughness Ra of its end face is preferably 100 nm or less, 50 nm or less, 25 nm or less, 15 nm or less, 10 nm or less, 9 nm or less, 8 nm or less, 7 nm or less, 6 nm or less, 5 nm or less, 4 nm or less, 3 nm or less, 2 nm or less, and particularly 1 nm or less. When the surface roughness Ra of the end face is too large, it is difficult for the light to enter the glass from the glass end face, and it is difficult for the light to exit from the inside of the glass to the outside of the glass, making it difficult to obtain the desired light transmittance. Moreover, the glass is easily damaged. On the other hand, when the surface roughness Ra of the end face is too small, when the end face is intended to physically support the glass by a support, the contact area between the glass and the support or the frictional resistance decreases, which may lead to difficulty in reliably supporting. In view of the above, the surface roughness Ra of the end face of the glass of the present invention is preferably 0.01 nm or more, 0.03 nm or more, 0.05 nm or more, 0.07 nm or more, 0.09 nm or more, 0.1 nm or more.

[0110] The low thermal expansion component of the present invention preferably has an unground surface. The theoretical strength of glass is originally very high, but in many cases, it breaks due to stress far lower than the theoretical strength. This is because nano-scale small defects called Griffith cracks are generated on the surface of the glass in the processes after glass forming, such as the grinding process. Therefore, if the surface of the low thermal expansion component of the present invention is not ground, the original mechanical strength is not easily damaged, and the glass is not easily broken. Moreover, the grinding process can be omitted and the manufacturing cost can be reduced. Among them, for example, when the component of the present invention is plate-shaped, if all the effective surfaces of the two main surfaces are unground surfaces, the component of the present invention is more difficult to break. And, in order to make all the effective surfaces unground surfaces, it is effective to make the part corresponding to the effective surface a free surface at the forming moment. In addition, even if the part corresponding to the effective surface contacts a solid component such as a forming jig at the time of forming, a smooth surface similar to a free surface can be produced by reheating this part at a temperature above the glass transition temperature.

[0111] The waviness of the low thermal expansion component of the present invention is preferably 10 μm or less, 5 μm or less, 4 μm or less, 3 μm or less, 2 μm or less, 1 μm or less, 0.8 μm or less, 0.7 μm or less, 0.6 μm or less, 0.5 μm or less, 0.4 μm or less, 0.3 μm or less, 0.2 μm or less, 0.1 μm or less, 0.08 μm or less, 0.05 μm or less, 0.03 μm or less, 0.02 μm or less, and particularly preferably 0.01 μm or less. When the waviness is too large, the incident angle of incident light on the glass surface is likely to be distributed at specific positions, and the amount of light scattering on the component surface increases on average, making it difficult to obtain the desired light transmittance. The lower limit of the waviness is not particularly limited, and in reality, it is 0.01 nm or more.

[0112] The wall thickness of the low thermal expansion component of the present invention is preferably 10 mm or less, 9 mm or less, 8 mm or less, 7 mm or less, 6 mm or less, 5 mm or less, and particularly preferably 4 mm or less. When the wall thickness of the specimen is too thick, the attenuation rate of light inside the component increases, making it difficult to obtain the desired light transmittance. In addition, when the component of the present invention is used for display purposes, the wall thickness is preferably 1000 μm or less, 500 μm, 200 μm or less, 100 μm or less, 70 μm or less, 50 μm or less, 30 μm or less, 1 to 20 μm, and particularly preferably 5 to 10 μm.

[0113] The difference between the maximum thickness and the minimum thickness of the low thermal expansion component of the present invention is preferably 50 μm or less, 25 μm or less, 10 μm or less, 5 μm or less, 1 μm or less, 500 nm or less, 300 nm or less, 100 nm or less, 50 nm or less, 25 nm or less, 15 nm or less, 10 nm or less, 9 nm or less, 8 nm or less, 7 nm or less, 6 nm or less, 5 nm or less, 4 nm or less, 3 nm or less, 2 nm or less, and particularly preferably 1 nm or less. When the difference between the maximum thickness and the minimum thickness is too large, the incident angle of light incident from either the front or the back surface and the exit angle when exiting from the other surface become different angles, and the light is undesirably scattered, easily forming a glaring appearance.

[0114] Among them, the surface roughness Ra of the main surface and the end surface of the component can be measured according to the method based on JIS B0601:2001. In addition, the waviness is measured using a stylus-type surface shape measuring device according to the method based on SEMI STD D15-1296 "Method for Measuring the Surface Waviness of FPD Glass Substrates". The wall thickness can be measured using a general device such as a digital vernier caliper or a point-contact type roughness meter.

[0115] The average microcrystalline size of the main crystal of the low thermal expansion component of the present invention is preferably 1000 nm or less, 500 nm or less, 300 nm or less, 100 nm or less, and particularly preferably 90 nm or less. When the average microcrystalline size of the main crystal is too large, the crystallized glass tends to become opaque. The lower limit of the average microcrystalline size of the main crystal is not particularly limited, and is actually 1 nm or more.

[0116] The low thermal expansion component of the present invention may also contain voids within the range that permits light transmittance. When voids are contained, there is a tendency for the coefficient of thermal expansion to decrease. As the size of the voids, for example, it is about several nm to 600 μm. The size of the nano-sized voids can be measured using a field emission scanning electron microscope (SU8220 manufactured by Hitachi High-Technologies Corporation), and the size of the micro-sized voids can be measured using a microfocus X-ray CT (manufactured by Shimadzu Corporation) or a polarized light microscope (ECLIPSE LV-100POL). When intending to reduce the coefficient of thermal expansion by using voids, the void fraction (the proportion of the volume of the voids in the low thermal expansion component in the overall volume) is preferably 0.01% or more, 0.05% or more, particularly 0.1% or more, and preferably 5% or less, 1% or less, particularly 0.5% or less. When the void fraction is too high, the mechanical strength of the obtained low thermal expansion component tends to decrease. Also, light is likely to scatter, and the light transmittance is likely to decrease. Among them, when measuring the void fraction, it is possible to use a microfocus X-ray CT (manufactured by Shimadzu Corporation) to photograph the inside of the specimen, and perform defect / inclusion analysis of VG STUDIO MAX manufactured by VOLUME GRAPHICS on the photographed image for measurement and calculation.

[0117] Examples

[0118] The present invention will be described below based on examples, but the present invention is not limited to the following examples. Tables 1 to 148 show the examples of the present invention (Sample Nos. 1 to 366).

[0119] [Table 1]

[0120]

[0121] [Table 2]

[0122]

[0123] [Table 3]

[0124]

[0125] [Table 4]

[0126]

[0127] [Table 5]

[0128]

[0129] [Table 6]

[0130]

[0131] [Table 7]

[0132]

[0133] [Table 8]

[0134]

[0135] [Table 9]

[0136]

[0137] [Table 10]

[0138]

[0139] [Table 11]

[0140]

[0141] [Table 12]

[0142]

[0143] [Table 13]

[0144]

[0145] [Table 14]

[0146]

[0147] [Table 15]

[0148]

[0149] [Table 16]

[0150]

[0151] [Table 17]

[0152]

[0153] [Table 18]

[0154]

[0155] [Table 19]

[0156]

[0157] [Table 20]

[0158]

[0159] [Table 21]

[0160]

[0161] [Table 22]

[0162]

[0163] [Table 23]

[0164]

[0165] [Table 24]

[0166]

[0167] [Table 25]

[0168]

[0169] [Table 26]

[0170]

[0171] [Table 27]

[0172]

[0173] [Table 28]

[0174]

[0175] [Table 29]

[0176]

[0177] [Table 30]

[0178]

[0179] [Table 31]

[0180]

[0181] [Table 32]

[0182]

[0183] [Table 33]

[0184]

[0185] [Table 34]

[0186]

[0187] [Table 35]

[0188]

[0189] [Table 36]

[0190]

[0191] [Table 37]

[0192]

[0193] [Table 38]

[0194]

[0195] [Table 39]

[0196]

[0197] [Table 40]

[0198]

[0199] [Table 41]

[0200]

[0201] [Table 42]

[0202]

[0203] [Table 43]

[0204]

[0205] [Table 44]

[0206]

[0207] [Table 45]

[0208]

[0209] [Table 46]

[0210]

[0211] [Table 47]

[0212]

[0213] [Table 48]

[0214]

[0215] [Table 49]

[0216]

[0217] [Table 50]

[0218]

[0219] [Table 51]

[0220]

[0221] [Table 52]

[0222]

[0223] [Table 53]

[0224]

[0225] [Table 54]

[0226]

[0227] [Table 55]

[0228]

[0229] [Table 56]

[0230]

[0231] [Table 57]

[0232]

[0233] [Table 58]

[0234]

[0235] [Table 59]

[0236]

[0237] [Table 60]

[0238]

[0239] [Table 61]

[0240]

[0241] [Table 62]

[0242]

[0243] [Table 63]

[0244]

[0245] [Table 64]

[0246]

[0247] [Table 65]

[0248]

[0249] [Table 66]

[0250]

[0251] [Table 67]

[0252]

[0253] [Table 68]

[0254]

[0255] [Table 69]

[0256]

[0257] [Table 70]

[0258]

[0259] [Table 71]

[0260]

[0261] [Table 72]

[0262]

[0263] [Table 73]

[0264]

[0265] [Table 74]

[0266]

[0267] [Table 75]

[0268]

[0269] [Table 76]

[0270]

[0271] [Table 77]

[0272]

[0273] [Table 78]

[0274]

[0275] [Table 79]

[0276]

[0277] [Table 80]

[0278]

[0279] [Table 81]

[0280]

[0281] [Table 82]

[0282]

[0283] [Table 83]

[0284]

[0285] [Table 84]

[0286]

[0287] [Table 85]

[0288]

[0289] [Table 86]

[0290]

[0291] [Table 87]

[0292]

[0293] [Table 88]

[0294]

[0295] [Table 89]

[0296]

[0297] [Table 90]

[0298]

[0299] [Table 91]

[0300]

[0301] [Table 92]

[0302]

[0303] [Table 93]

[0304]

[0305] [Table 94]

[0306]

[0307] [Table 95]

[0308]

[0309] [Table 96]

[0310]

[0311] [Table 97]

[0312]

[0313] [Table 98]

[0314]

[0315] [Table 99]

[0316]

[0317] [Table 100]

[0318]

[0319] [Table 101]

[0320]

[0321] [Table 102]

[0322]

[0323] [Table 103]

[0324]

[0325] [Table 104]

[0326]

[0327] [Table 105]

[0328]

[0329] [Table 106]

[0330]

[0331] [Table 107]

[0332]

[0333] [Table 108]

[0334]

[0335] [Table 109]

[0336]

[0337] [Table 110]

[0338]

[0339] [Table 111]

[0340]

[0341] [Table 112]

[0342]

[0343] [Table 113]

[0344]

[0345] [Table 114]

[0346]

[0347] [Table 115]

[0348]

[0349] [Table 116]

[0350]

[0351] [Table 117]

[0352]

[0353] [Table 118]

[0354]

[0355] [Table 119]

[0356]

[0357] [Table 120]

[0358]

[0359] [Table 121]

[0360]

[0361] [Table 122]

[0362]

[0363] [Table 123]

[0364]

[0365] [Table 124]

[0366]

[0367] [Table 125]

[0368]

[0369] [Table 126]

[0370]

[0371] [Table 127]

[0372]

[0373] [Table 128]

[0374]

[0375] [Table 129]

[0376]

[0377] [Table 130]

[0378]

[0379] [Table 131]

[0380]

[0381] [Table 132]

[0382]

[0383] [Table 133]

[0384]

[0385] [Table 134]

[0386]

[0387] [Table 135]

[0388]

[0389] [Table 136]

[0390]

[0391] [Table 137]

[0392]

[0393] [Table 138]

[0394]

[0395] [Table 139]

[0396]

[0397] [Table 140]

[0398]

[0399] [Table 141]

[0400]

[0401] [Table 142]

[0402]

[0403] [Table 143]

[0404]

[0405] [Table 144]

[0406]

[0407] [Table 145]

[0408]

[0409] [Table 146]

[0410]

[0411] [Table 147]

[0412]

[0413] [Table 148]

[0414]

[0415] First, in order to obtain a glass having a composition as described in each table, each raw material is mixed in the form of oxides, hydroxides, carbonates, nitrates, etc. to obtain a raw material batch (the composition described in each table is the analysis value of the glass actually obtained. In the table, the sum or ratio of each component, such as "Li+Na+K", is expressed by omitting the oxygen element and coefficient). The obtained raw material batch is added to a crucible containing platinum and rhodium, a reinforced platinum crucible not containing rhodium, a refractory crucible, a quartz crucible, etc., and melted at 1630°C for 17 to 20 hours, then heated to 1650°C and melted for 2 hours, roll-formed into a thickness of 5 mm, and then heat-treated at 700 to 750°C for 30 minutes in an annealing furnace, and the annealing furnace is cooled to room temperature at 100°C / h to obtain a crystalline glass (raw glass) as a precursor before crystallization. Among them, the melting is carried out by the electric melting method widely used in the development of glass components.

[0416] In addition, using the glass composition of sample No. 102, it was confirmed that the glass composition in contact with liquid or solid can be melted by laser irradiation. In addition, it was also confirmed that the glass composition in contact with gas only can be melted by laser while gas is transported from the periphery of the glass sample to suspend the glass sample. It was also confirmed that after the molten liquid is made in advance by an electric furnace, it can be formed into a hemispherical shape, a spherical shape, a fiber shape, a powder shape, etc. by a pressing method, a re-drawing method, a spraying method, etc. In addition, using the glass composition of sample No. 102, it was confirmed that melting can be achieved by a continuous furnace combining burner heating and electric heating. In addition, it was confirmed that it can be formed into a block shape, a peeling shape, a hollow shape, etc. by a roller method, a film method, a batch method using dielectric heating, etc. In addition, using the glass composition of sample No. 102, it was confirmed that it can be made into a thin plate shape, a tube shape, and a valve shape by an up-pull method, a down-pull method, a slit method, an overflow (melting) method, a hand-blowing method, etc. In addition, using the glass composition of sample No. 102, it was confirmed that the glass composition could be solidified into a plate shape by pouring the glass melt of sample No. 102 onto a liquid with a larger specific gravity than the sample and then cooling it. However, the glass produced by any method could be crystallized under the conditions described in the table.

[0417] The Pt and Rh contents of the specimens were analyzed using an ICP-MS apparatus (Agilent 8800 manufactured by AGILEINT TECHNOLOGY). First, the prepared glass specimens were crushed, wetted with pure water, and then perchloric acid, nitric acid, sulfuric acid, hydrofluoric acid, etc. were added to dissolve them. After that, the Pt and Rh contents of the specimens were measured using ICP-MS (Inductively Coupled Plasma Mass Spectrometry). A calibration curve was made using Pt and Rh solutions with known concentrations prepared in advance, and the Pt and Rh contents of each measured specimen were calculated based on this calibration curve. The measurement modes were set as Pt: He gas / HMI (low mode), Rh: HEHe gas / HMI (medium mode), and the mass numbers were set as Pt: 198, Rh: 103. Additionally, the Li 2 O content of the specimens was analyzed using an atomic absorption spectrometry apparatus (ContrAA600 manufactured by Analytik Jena). The dissolution process of the glass specimens, the use of the calibration curve, etc. were basically the same as those for the Pt and Rh analyses. Exceptionally, for other components, the same as for Pt, Rh, and Li 2 O, they were measured using ICP-MS or atomic absorption spectrometry, or known-concentration glass specimens previously measured using an ICP-MS or atomic absorption spectrometry apparatus were used as calibration curve specimens, and a calibration curve was made using an XRF (X-ray fluorescence) analyzer (ZSX PrimusIV manufactured by RIGAKU). Then, based on this calibration curve, the actual contents of each component were determined from the XRF analysis values of the measured specimens. During XRF analysis, the tube voltage, tube current, exposure time, etc. were adjusted according to the analysis components at any time.

[0418] For the original glasses described in each table, heat treatment was performed under the crystallization conditions described in each table. For the obtained crystallized glasses, the transmittance (total light transmittance), diffuse transmittance, L ＊ value, a ＊ value, b ＊ value, precipitated crystals, average crystallite size, coefficient of thermal expansion, density, surface roughness, and waviness were evaluated. And for the original glasses before crystallization, the viscosity, liquidus temperature, liquidus viscosity, coefficient of thermal expansion, density, and β-OH value were measured.

[0419] The transmittance was evaluated by measuring a crystallized glass plate with an optically polished surface having a wall thickness of 4 mm using a spectrophotometer. The measurement was performed using a spectrophotometer V-670 manufactured by JASCO Corporation. Among them, the V-670 is equipped with an integrating sphere unit "ISN-723", and the measured transmittance corresponds to the total light transmittance. In addition, the measurement wavelength range is 200 to 1500 nm, the scanning speed is 200 nm / minute, the sampling interval is 1 nm, the bandwidth is 5 nm in the wavelength range of 200 to 800 nm, and the bandwidth is 20 nm in the wavelength range outside thereof. Before the measurement, baseline correction (set to 100%) and dark field measurement (set to 0%) were performed. The dark field measurement was performed with the barium sulfate plate attached to the ISN-723 removed. Using the measured transmittance, the tristimulus values XYZ were calculated based on JIS Z8781-4:2013 and its corresponding international standard, and the lightness and chromaticity (light source C / 10°) were calculated from each stimulus value. In addition, the diffuse transmittance of the crystallized glass was measured using the same model as above, with the measurement sample set in a state where the barium sulfate plate attached to the ISN-723 was removed.

[0420] The precipitated crystals were evaluated using an X-ray diffractometer (Aeris manufactured by Spectris Co., Ltd.). The scanning mode was 2θ / θ measurement, the scanning type was continuous scanning, the scattering slit width was 9 mm, the divergence slit width was 1 / 4°, the receiving slit was open, the measurement range was 5 to 60°, the measurement step was 0.01°, the scanning speed was 1.5° / minute, and the main crystal and crystal grain size were evaluated using the analysis software installed in the same model package. As the type of precipitated crystal identified as the main crystal, α-cordierite is expressed as "α-Cor." in the table. In addition, the average grain size of the main crystal was calculated using the measured X-ray diffraction peak based on the Debye-Sherrer method. In addition, the XRD spectrum of sample No. 127 is shown in Figure 1 .

[0421] Regarding the coefficient of thermal expansion, a sample obtained by processing a plate-shaped crystallized glass with a wall thickness of 5 to 7 mm into was used, and the average coefficient of linear thermal expansion measured in the temperature ranges of 30 to 380 °C and 30 to 750 °C was used for evaluation. The measurement was performed using a dilatometer manufactured by NETZSCH.

[0422] The density was evaluated using the Archimedes method.

[0423] The high-temperature viscosity was evaluated by the platinum ball pulling method. During the evaluation, the massive glass sample was broken into appropriate sizes and put into an alumina crucible in such a way that air bubbles were not involved as much as possible. Then, the alumina crucible was heated to make the sample into a molten state, and the measured values of the glass viscosity at multiple temperatures were obtained. The constants of the Vogel-Fulcher formula were calculated to produce a viscosity curve, and the temperature at each viscosity was calculated.

[0424] The liquidus temperature was evaluated by the following method. First, glass powder with a uniform size of 300 - 500 μm was filled into a platinum boat of about 120×20×10 mm, put into an electric furnace, and melted at 1600 °C for 30 minutes. After that, it was transferred to an electric furnace with a linear temperature gradient and left for 20 hours to precipitate devitrified matter. After the measured sample was cooled to room temperature, the devitrified matter precipitated at the interface between the platinum boat and the glass was observed, and the temperature of the devitrified matter precipitation site was calculated based on the temperature gradient curve of the electric furnace as the liquidus temperature. Moreover, the obtained liquidus temperature was substituted into the high-temperature viscosity curve of the glass, and the viscosity corresponding to the liquidus temperature was used as the liquidus viscosity.

[0425] The β-OH value was obtained by measuring the transmittance of the glass using an infrared spectrometer (FT-IR Frontier manufactured by Perkin Elmer Company) and using the following formula. Among them, the scanning speed was set at 100 μm / min, the sampling interval was set at 1 cm -1 , and the number of scans was set at 10 times per scan in each measurement.

[0426] β-OH value = (1 / X)log(T 1 / T 2 )

[0427] X: Glass wall thickness

[0428] T 1 : Transmittance at a reference wavenumber of 3846 cm -1

[0429] T 2 : Minimum transmittance near the OH group absorption wavenumber of 3600 cm -1

[0430] The average surface roughness Ra and waviness of the main surface and end surface of the sample were measured by the above method.

[0431] The size of the voids and the porosity were measured using a microfocus X-ray CT (manufactured by Shimadzu Corporation). The size of the voids in the low thermal expansion component of Specimen No. 306 was from several nm to 330 μm or less, and the porosity was 0.28%. Moreover, the histogram of the measurement results of the void size of Specimen No. 306 is shown in Figure 2 .

[0432] ​​As can be seen from Tables 1 to 148, the low thermal expansion components (crystallized glass) of Specimens No. 1 to 366 as examples have a low coefficient of linear expansion. Also, these specimens do not contain Li 2 O, or if they do, it is in trace amounts, and thus can be produced at low cost. Also, Specimens No. 169, 173, 175, 183, 204 to 206, 211 to 213, 218 to 221, 312 to 320, 361, 366 were colored, and in particular, Specimens No. 183, 221 were black.

[0433] Industrial Applicability

[0434] The low thermal expansion component of the present invention is applicable to front windows of kerosene stoves, wood stoves, etc., substrates for high-tech products such as color filters or substrates for image sensors, fixtures for firing electronic devices, light diffusing plates, furnace cores for semiconductor manufacturing, masks for semiconductor manufacturing, optical lenses, components for dimensional measurement, components for communication, fireproof windows, building components, heat-resistant tableware, containers for chemical reactions, top plates for cookers such as electromagnetic cookers, heat-resistant tableware, heat-resistant covers, window glass for fire doors, components for celestial telescopes, components for space optics, etc.

Claims

1. A low thermal expansion component, characterized in that: Contains MgO-Al2O3-SiO2 system crystals.

2. The low thermal expansion component according to claim 1, characterized in that Contains α-cordierite and is translucent.

3. The low thermal expansion component according to claim 2, characterized in that: The content of SiO2 is 20 to 90% by mass, Al2O3 is greater than 0 and less than 50% by mass, and MgO is greater than 0 and less than 40% by mass.

4. The low thermal expansion component according to claim 2 or 3, characterized in that: In terms of mass %, SiO2 / (SiO2+Al2O3+MgO) is 0.45 to 0.

81.

5. The low thermal expansion component according to claim 2 or 3, characterized in that: In terms of mass %, Al2O3 / (SiO2+Al2O3+MgO) is 0.01 to 0.

45.

6. The low thermal expansion component according to claim 2 or 3, characterized in that: In terms of mass %, MgO / (SiO2+Al2O3+MgO) is 0.03 to 0.

29.

7. The low thermal expansion component according to claim 2 or 3, characterized in that: The SiO2 / Al2O3 ratio is 1 to 15 in mass %.

8. The low thermal expansion component according to claim 2 or 3, characterized in that: SiO2 / MgO is 2 to 15 in mass %.

9. The low thermal expansion component according to claim 2 or 3, characterized in that: In terms of mass %, Al2O3 / MgO is 0.2 to 15.

10. The low thermal expansion component according to claim 2 or 3, characterized in that: In terms of mass%, BaO is 0 to 5.6%, SiO2 / Al2O3 is 2.5 to 15, and SiO2 / MgO is 5.4 to 15.

11. The low thermal expansion component according to claim 2 or 3, characterized in that: In terms of mass%, BaO is 0 to 5.6%, SiO2 / Al2O3 is 2.5 to 15, and Al2O3 / MgO is 1.8 to 15.

12. The low thermal expansion component according to claim 2 or 3, characterized in that: In terms of mass %, SiO2 is 55.5 to 90% and ZnO is greater than 0%.

13. The low thermal expansion component according to claim 2 or 3, characterized in that: In terms of mass %, (Li2O+Na2O+K2O) / SiO2 is 0.00005 to 0.

03.

14. The low thermal expansion component according to claim 2 or 3, characterized in that: In terms of mass %, Li2O+Na2O+K2O+CaO+SrO+BaO is less than 2%.

15. The low thermal expansion component according to claim 2 or 3, characterized in that: In terms of mass %, (SiO2+ZnO) / (MgO+Al2O3) is 0.7 to 3.

16. The low thermal expansion component according to claim 2 or 3, characterized in that: In terms of mass %, ZnO-(TiO2+ZrO2) is -15 to 5%.

17. The low thermal expansion component according to claim 2 or 3, characterized in that: In terms of mass %, TiO2 / (TiO2+Fe2O3) is 0.001 to 0.

999.

18. The low thermal expansion component according to claim 2 or 3, characterized in that: Contains one or more of MoO3, V2O5, CuO, NiO, MnO2, Cr2O3, Nd2O3, WO3, and Co3O4.

19. The low thermal expansion component according to claim 2 or 3, characterized in that: Contains more than 0% of MoO3 in terms of mass%.

20. The low thermal expansion component according to claim 2 or 3, characterized in that: In terms of mass%, SiO2 / (SiO2+Al2O3+MgO) is 0.36-0.81, Al2O3 / (SiO2+Al2O3+MgO) is 0.09-0.5, MgO / (SiO2+Al2O3+MgO) is 0.01-0.29, and Na2O is 0.01% or more and less than 2.5%. Contains at least one of As2O3, Sb2O3, SnO2, and Cl.

21. The low thermal expansion component according to claim 1 or 2, characterized in that: The β-OH value is greater than 0 and is less than 2 / mm.

22. The low thermal expansion component according to claim 1 or 2, characterized in that: The transmittance at a thickness of 4 mm and a wavelength of 1200 nm is 10% or more.

23. The low thermal expansion component according to claim 1 or 2, characterized in that: The thermal expansion coefficient at 30-380°C is 30×10 -7 / ℃ below.

24. The low thermal expansion component according to claim 1 or 2, characterized in that: The thermal expansion coefficient at 30-750°C is 30×10 -7 / ℃ below.

25. The low thermal expansion component according to claim 1 or 2, characterized in that: It is crystallized glass.

26. A precursor of a low thermal expansion component, characterized in that: It is formed by crystalline glass, which contains, in mass %, 20 to 90% SiO2, greater than 0 and less than 50% Al2O3, greater than 0 and less than 40% MgO, 0 to 20% CaO, 0 to 20% SrO, 0 to 20% BaO, 0 to 20% ZnO, 0 to 10% Li2O, 0 to 20% Na2O, 0 to 20% K2O, 0 to 20% B2O3, 0 to 20% P2O5, 0 to 20% TiO2, 0 to 20% ZrO2, 0 to 10% HfO2, and 0 to 20% SnO2.

27. A method for manufacturing a low thermal expansion component, used for manufacturing the low thermal expansion component according to claim 25, the method comprising: A step of heating and melting the raw materials and then molding them to obtain crystallizable glass; and A step of heat-treating the crystallizable glass to crystallize it.

28. The method for manufacturing a low thermal expansion component according to claim 27, characterized in that: The amount of metal Al added to the raw material is greater than 0 and not more than 5000 ppm in terms of mass %.

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