Crystallized glass, high frequency substrate, antenna for liquid crystals, and method for producing crystallized glass

Abstract

To provide a crystallized glass in which cracking due to a difference in the coefficient of thermal expansion between a crystalline phase and a glass phase is suppressed while achieving excellent dielectric properties.SOLUTION: The present invention relates to a crystallized glass comprising crystals of at least one of indialite and cordierite, in which the total amount of the crystals is 40 mass% or more of the crystallized glass, and each of the crystals contains at least one of a void space and a different element in an Al site.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a crystallized glass, a high frequency substrate, an antenna for liquid crystal displays, and a method for producing the crystallized glass. [Background technology]

[0002] In recent years, wireless transmission using microwave and millimeter wave bands has been attracting attention as a large-capacity transmission technology. As the signal frequency increases with the expansion of the frequency bands used, there is a demand for dielectric substrates with excellent dielectric properties at high frequencies.

[0003] Examples of materials for the dielectric substrate include quartz, ceramics, and glass. Among glasses, crystallized glass, which is obtained by partially crystallizing glass, has the advantage of being easier to mold and cheaper to manufacture than quartz or ceramics, and of having better dielectric properties. Examples of crystallized glass with excellent dielectric properties include crystallized glass containing indialite or cordierite crystals, as disclosed in Patent Document 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 023205 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the proportion of indialite or cordierite crystals in the crystallized glass is increased in order to improve the dielectric properties, there is a problem that cracks occur due to the difference in thermal expansion coefficient between the crystal phase and the glass phase. Therefore, an object of the present invention is to solve the above problems and to provide crystallized glass that contains a large amount of indialite and cordierite crystals, achieves excellent dielectric properties, and is also inhibited from cracking. [Means for solving the problem]

[0006] That is, the present invention provides a crystallized glass containing at least one crystal of indialite and cordierite, The total amount of the crystals is 40% by mass or more of the crystallized glass, The crystals provide a crystallized glass containing at least one of vacancies and foreign elements at the Al sites. In one embodiment of the crystallized glass of the present invention, the portion containing at least one of the vacancies and the different element may occupy 4 atom % or more of the Al sites in total. In one embodiment of the crystallized glass of the present invention, Mass percentage based on oxides SiO2 45-60%, Al2O3 20-35%, MgO 9-15%, It may contain. In one embodiment of the crystallized glass of the present invention, TiO2 may be contained in an amount of 5 to 15% in terms of mass percentage based on oxides. In one embodiment of the crystallized glass of the present invention, P2O5 may be contained in an amount of 0.5 to 15% in terms of mass percentage based on oxides. In one embodiment of the crystallized glass of the present invention, the crystallized glass has main surfaces facing each other, and the areas of the main surfaces are 100 to 100,000 cm 2 and the thickness may be 0.01 to 2 mm. In one embodiment of the crystallized glass of the present invention, the thermal conductivity at 20° C. may be 1.0 W / (m·K) or more. In one embodiment of the crystallized glass of the present invention, the relative dielectric constant at 20° C. and 10 GHz may be 7 or less. In one embodiment of the crystallized glass of the present invention, the dielectric loss tangent at 20° C. and 10 GHz may be 0.003 or less. In one embodiment of the crystallized glass of the present invention, the average thermal expansion coefficient at 50 to 350°C may be 1 ppm / °C or more.

[0007] The present invention provides a high frequency substrate using the above crystallized glass.

[0008] The present invention provides an antenna for a liquid crystal display using the above-mentioned crystallized glass.

[0009] The present invention relates to a composition comprising the following components, expressed in mass percentage based on oxides: SiO2 45-60%, Al2O3 20-35%, MgO 9-15%, P2O5 0.5-15%, TiO2 5-15%, The present invention provides an amorphous glass containing

[0010] The present invention relates to a composition comprising the following components, expressed in mass percentage based on oxides: SiO2 45-60%, Al2O3 20-35%, MgO 9-15%, providing an amorphous glass containing A method for producing crystallized glass, comprising heat-treating the amorphous glass, The present invention provides a method for producing crystallized glass, which comprises precipitating at least one of indialite and cordierite crystals in the heat treatment and causing at least one of vacancies and a different element to exist at the Al site of the crystals. In one embodiment of the method for producing crystallized glass of the present invention, the amorphous glass is Mass percentage based on oxides P2O5 0.5-15%, TiO2 5-15%, It may contain. In one embodiment of the method for producing crystallized glass of the present invention, the amorphous glass has main surfaces facing each other, and the areas of the main surfaces are 100 to 100,000 cm 2 The amorphous glass may have a thickness of 0.01 to 2 mm. In one embodiment of the method for producing crystallized glass of the present invention, the heat treatment may include holding the amorphous glass at 960° C. or higher for 0.5 hours or more. In one embodiment of the method for producing crystallized glass of the present invention, the heat treatment includes holding in a first temperature range and holding in a second temperature range, the first temperature range is 760°C or more and 960°C or less, and the holding time in the first temperature range is 0.5 hours or more; The second temperature range may be 960° C. or higher and 1350° C. or lower, and the holding time in the second temperature range may be 0.5 hours or longer. [Effects of the Invention]

[0011] According to the present invention, crystallized glass is obtained that achieves excellent dielectric properties by containing 40 mass% or more of at least one of indialite and cordierite crystals, and that contains at least one of vacancies and heterogeneous elements in the Al site of the crystals, thereby suppressing cracking due to the difference in thermal expansion coefficient between the crystalline phase and the glass phase, as well as a high-frequency substrate and a liquid crystal antenna that use this crystallized glass. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing a schematic diagram of temperature changes in a two-stage heat treatment. DETAILED DESCRIPTION OF THE INVENTION

[0013] In this specification, the use of "to" to indicate a range of values ​​means that the values ​​before and after it are included as the lower and upper limits. Unless otherwise specified, "to" will be used in the same sense hereinafter in this specification.

[0014] In this specification, unless otherwise specified, glass compositions are expressed in terms of mass percentage based on oxides, and mass% is simply expressed as "%." Note that in this specification, a mass-based ratio (e.g., percentage) and a weight-based ratio (e.g., percentage) are the same. In addition, in this specification, "substantially free" means that the content is at or below the level of impurities contained in raw materials, etc., that is, that the content is not intentionally added. Specifically, for example, it is less than 0.1% by mass.

[0015] In this specification, "glass-ceramics" refers to glass in which crystals are precipitated. In this application, "glass-ceramics" refers to glass in which diffraction peaks indicating crystals are observed by X-ray diffraction (XRD). X-ray diffraction measurement is performed, for example, using CuKα radiation in the range of 2θ of 10° to 80°, and if diffraction peaks appear, precipitated crystals can be identified, for example, by the three-strong ray method.

[0016] <Glass-ceramics> The crystallized glass according to this embodiment (hereinafter also referred to as the present crystallized glass) is a crystallized glass containing at least one of indialite and cordierite crystals, the total amount of the crystals being 40% by mass or more of the crystallized glass, and the crystals containing at least one of vacancies and heteroelements at the Al site.

[0017] (crystal) This glass-ceramic contains at least one of indialite and cordierite crystals. Indialite and cordierite are MgO-Al2O3-SiO2 crystals with the same composition but different crystal structures. The composition of these crystals is expressed by the chemical formula Mg2Al4Si5O 18 When synthesized by a solid-state reaction method, cordierite is a low-temperature type with an orthorhombic crystal structure, while indialite is a high-temperature type with a hexagonal crystal structure. Hereinafter, in this specification, at least one crystal of indialite and cordierite contained in crystallized glass may be collectively referred to as "indialite / cordierite crystal." That is, "indialite / cordierite crystal" refers to one crystal when the crystallized glass contains either indialite or cordierite, or to both crystals when the crystallized glass contains both indialite and cordierite.

[0018] Insulating substrates used in high-frequency devices are required to reduce transmission losses due to dielectric loss, conductor loss, etc., in order to ensure characteristics such as the quality and strength of high-frequency signals. Crystallized glass containing indialite / cordierite crystals tends to have smaller dielectric loss tangents and dielectric constants as the proportion of these crystals in the crystallized glass increases. Furthermore, between indialite and cordierite, indialite tends to have more excellent dielectric properties, and it is therefore preferable for the crystallized glass to contain indialite.

[0019] To obtain crystallized glass with excellent dielectric properties, the total amount of indialite / cordierite crystals in the crystallized glass is 40% by mass or more of the crystallized glass, and preferably 50% by mass or more, more preferably 55% by mass or more, and even more preferably 60% by mass or more.

[0020] Furthermore, from the viewpoint of suppressing cracking due to the difference in thermal expansion coefficient between the crystalline phase and the glass phase, and from the viewpoint of ensuring a sufficient thermal expansion coefficient for the crystallized glass, the total amount of indialite / cordierite crystals is preferably 90 mass% or less of the crystallized glass, more preferably 85 mass% or less, and even more preferably 80 mass% or less.

[0021] Here, indialite / cordierite crystals can be identified by X-ray diffraction (XRD) measurement. Specifically, when a bulk of crystallized glass is crushed and measured by XRD using CuKα radiation at 2θ=10 to 90°, if the peak with the highest intensity is confirmed in the range of 2θ=10 to 11° and can be defined as the peak of the (100) plane, the crystallized glass contains at least one of indialite and cordierite crystals.

[0022] In addition, to obtain a more accurate crystal structure, it is preferable to perform Rietveld analysis. Rietveld analysis enables quantitative analysis of crystalline and amorphous phases and structural analysis of crystalline phases. The Rietveld method is described in "Crystal Analysis Handbook" (Kyoritsu Shuppan, 1999, pp. 492-499), edited by the Editorial Committee of the Crystallographic Society of Japan. The content of indialite / cordierite crystals in this glass-ceramics can be calculated by Rietveld analysis using the results of XRD measurements.

[0023] In this crystallized glass, the indialite / cordierite crystals contain at least one of vacancies and heterogeneous elements at the Al site. Here, heterogeneous elements refer to elements other than Al. That is, the indialite / cordierite crystals of this crystallized glass contain portions where no Al atoms are present, at sites where Al atoms would normally occupy if an ideal crystal structure were repeated. When no atoms, including atoms of heterogeneous elements, are present in a portion where no Al atoms are present, the portion is a vacancy, and when atoms of heterogeneous elements are present, the portion is a portion containing the heterogeneous element.

[0024] The different element is not particularly limited, but examples thereof include elements other than Al whose atomic size is relatively close to that of Al atoms, such as Mg and Si.

[0025] By containing at least one of vacancies and a different element at the Al site of the indialite / cordierite crystal, cracking of the glass-ceramic due to the difference in thermal expansion coefficient between the crystalline phase and the glass phase can be suppressed. By containing at least one of vacancies and a different element at the Al site of the indialite / cordierite crystal, the crystal structure becomes a structure that is somewhat distorted compared to an ideal crystal structure, that is, a structure in which the lattice constant is elongated or contracted in a certain axial direction compared to the original lattice constant. This is thought to relieve stress generated in the glass-ceramic due to the difference in thermal expansion coefficient between the crystalline phase and the glass phase, thereby suppressing cracking.

[0026] Furthermore, when indialite / cordierite crystals contain vacancies at the Al site, there are fewer atoms in the crystal than when they have an ideal crystal structure. It is known that dielectric properties change depending on the number of electrons, and the greater the number of electrons, the higher the dielectric constant tends to be. In other words, the presence of vacancies at the Al site reduces the number of electrons compared to when Al atoms are present, which is thought to result in better dielectric properties for the glass-ceramic. From this, it is also considered that when the Al site contains a hetero element, if the number of electrons is reduced compared to when an Al atom is present, the dielectric properties are also likely to be improved. Therefore, from the viewpoint of further improving the dielectric properties, it is preferable that the hetero element has fewer electrons than Al. An example of such a hetero element is Mg.

[0027] In the indialite / cordierite crystal, the total of the portions containing at least one of vacancies and heteroelements at the Al sites, i.e., the portions where no Al atoms are present at the Al sites, is preferably 4 atom% or more of the Al sites from the viewpoint of improving the crack suppression effect. The total of the portions where no Al atoms are present is more preferably 5 atom% or more, even more preferably 7.5 atom% or more, still more preferably 9 atom% or more, particularly preferably 10 atom% or more, and even more particularly preferably 12 atom% or more. Furthermore, the total amount of Al sites where no Al atoms are present is preferably 50 atom % or less, more preferably 35 atom % or less, and even more preferably 20 atom % or less, from the viewpoint of maintaining the crystal structure.

[0028] The portion where no Al atoms are present may be entirely vacancies, or may be entirely a portion containing a different element. However, from the viewpoint of enhancing the effects of suppressing cracking and improving dielectric properties, it is preferable that the portion contains vacancies, and it is even more preferable that the portion contains more vacancies than the portion containing a different element.

[0029] The ratio of the total number of Al-free sites to the total number of Al-sites is the atomic fraction (atom %) of Al-free sites to the number of Al-sites that would be occupied by Al atoms in an ideal crystal structure. This ratio can be calculated by Rietveld analysis using the results of XRD measurements.

[0030] The crystallized glass may contain crystals other than indialite / cordierite crystals, provided that the effects of the present invention are not impaired. Examples of crystals other than indialite / cordierite crystals include mullite, corundum, rutile, and anatase. When crystals other than indialite / cordierite crystals are contained, the total content of such crystals is preferably 15% by mass or less, more preferably 12.5% ​​by mass or less, and even more preferably 10% by mass or less, based on the entire crystallized glass. The identification of the crystal species and measurement of the content of crystals other than indialite / cordierite crystals can be performed by the above-mentioned XRD measurement and Rietveld analysis using the XRD measurement results.

[0031] (composition) The composition of this crystallized glass is the same as the composition of the amorphous glass before crystallization in the manufacturing method described below. Therefore, the preferred composition of this crystallized glass and the preferred composition of the amorphous glass are the same. Here, the composition of the crystallized glass in this specification refers to the composition obtained by adding the composition of the crystalline phase and the glass phase of the crystallized glass. The composition of the crystallized glass can be determined by heat-treating the crystallized glass at a temperature above its melting point and analyzing the vitrified product. Examples of analytical methods include X-ray fluorescence analysis. The composition of the crystallized phase of this crystallized glass can be analyzed by Rietveld analysis of the results of the XRD measurement described above. In the composition of this crystallized glass, the preferred lower limit of the content of non-essential components is 0%.

[0032] The composition of the present crystallized glass is not particularly limited, but preferably contains 45 to 60% SiO2, 20 to 35% Al2O3, and 9 to 15% MgO, expressed as mass percentages based on oxides. SiO2, Al2O3, and MgO are components that make up indialite / cordierite crystals.

[0033] SiO2 is a component for precipitating indialite / cordierite crystals as a crystalline phase. The SiO2 content is preferably 45% or more. When the SiO2 content is 45% or more, the precipitated crystalline phase of the glass-ceramics is likely to be stable. The SiO2 content is more preferably 45.2% or more, even more preferably 45.5% or more, even more preferably 45.7% or more, particularly preferably 46% or more, even more preferably 46.2% or more, and most preferably 46.5% or more. Furthermore, the SiO2 content is preferably 60% or less. When the SiO2 content is 60% or less, the glass raw material is easily melted and molded. Furthermore, heat treatment conditions are also an important factor for precipitating indialite / cordierite crystals as a crystalline phase, and when the SiO2 content is below the above upper limit, a wider range of heat treatment conditions can be selected. The SiO2 content is more preferably 58% or less, even more preferably 56% or less, even more preferably 54% or less, particularly preferably 52% or less, even more preferably 50% or less, and most preferably 48% or less.

[0034] Al2O3 is a component for precipitating indialite / cordierite crystals as a crystalline phase. The Al2O3 content is preferably 20% or more. When the Al2O3 content is 20% or more, the desired crystalline phase is easily obtained, the precipitated crystalline phase of the crystallized glass is easily stabilized, and an increase in the liquidus temperature can be suppressed. The Al2O3 content is more preferably 22% or more, even more preferably 24% or more, even more preferably 26% or more, particularly preferably 28% or more, even more preferably 29%, and most preferably 30% or more. On the other hand, the Al2O3 content is preferably 35% or less. When the Al2O3 content is 35% or less, the meltability of the glass raw material is likely to be good. The Al2O3 content is more preferably 34.5% or less, even more preferably 34% or less, even more preferably 33.5% or less, particularly preferably 33% or less, even more preferably 32.5% or less, and most preferably 32% or less.

[0035] MgO is a component for precipitating indialite / cordierite crystals as a crystalline phase. The MgO content is preferably 9% or more. When the MgO content is 9% or more, the desired crystals are easily obtained, the precipitated crystal phase of the crystallized glass is easily stabilized, and the meltability of the glass raw material is improved. The MgO content is more preferably 9.3% or more, even more preferably 9.5% or more, even more preferably 9.7% or more, particularly preferably 10% or more, even more preferably 10.2%, and most preferably 10.5% or more. On the other hand, the MgO content is preferably 15% or less. When the MgO content is 15% or less, the desired crystals are easily obtained. The MgO content is more preferably 14.5% or less, even more preferably 14% or less, even more preferably 13.5% or less, particularly preferably 13% or less, even more preferably 12.5% ​​or less, and most preferably 12% or less.

[0036] The present crystallized glass preferably contains a nucleation component. The nucleation component is a component that can generate nuclei that serve as starting points for crystal growth when crystallizing amorphous glass. By including the nucleation component, it becomes easier to stably obtain the desired crystal structure and a state in which crystals are dispersed relatively uniformly in the crystallized glass. Examples of the nucleation component include TiO2, MoO3, and ZrO2. As the nucleation component, TiO2 is preferred from the viewpoint of stably precipitating indialite / cordierite crystals.

[0037] The total content of the nucleation components is preferably 5% or more, more preferably 5.5% or more, even more preferably 6.0% or more, even more preferably 6.5% or more, particularly preferably 7.0% or more, even more preferably 7.5%, and most preferably 8.0% or more, from the viewpoint of having the nucleation components present at a certain concentration throughout the glass as nucleating agents. The total content of the nucleation components is preferably 15% or less, more preferably 14.5% or less, even more preferably 14% or less, even more preferably 13.5% or less, particularly preferably 13% or less, even more preferably 12.5% ​​or less, and most preferably 12% or less, from the viewpoint of increasing the proportion of indialite / cordierite crystals in the entire crystallized glass and improving the dielectric properties.

[0038] Although TiO2 is not an essential component, it not only functions as the nucleation component described above, but also contributes to refining the precipitated crystalline phase, improving the mechanical strength of the material, and improving chemical durability. When TiO2 is contained, its content is preferably 5% or more, more preferably 5.5% or more, even more preferably 6.0% or more, even more preferably 6.5% or more, particularly preferably 7.0% or more, even more preferably 7.5%, and most preferably 8.0% or more, from the viewpoint of stably precipitating indialite / cordierite crystals. Furthermore, the TiO2 content is preferably 15% or less, more preferably 14.5% or less, even more preferably 14% or less, even more preferably 13.5% or less, particularly preferably 13% or less, even more preferably 12.5% ​​or less, and most preferably 12% or less, from the viewpoint of increasing the proportion of indialite / cordierite crystals in the entire crystallized glass and improving dielectric properties.

[0039] MoO3 is not an essential component, but it functions as the nucleation component described above. When MoO3 is contained, the content is preferably 5% or more from the viewpoint of stably precipitating indialite / cordierite crystals, more preferably 5.5% or more, even more preferably 6.0% or more, even more preferably 6.5% or more, particularly preferably 7.0% or more, even more preferably 7.5%, and most preferably 8.0% or more. Furthermore, the content of MoO3 is preferably 15% or less from the viewpoint of increasing the proportion of indialite / cordierite crystals in the entire crystallized glass and improving the dielectric properties, more preferably 14.5% or less, even more preferably 14% or less, even more preferably 13.5% or less, particularly preferably 13% or less, even more preferably 12.5% ​​or less, and most preferably 12% or less.

[0040] ZrO2 is not an essential component, but in addition to functioning as the nucleation component described above, it also contributes to refining the precipitated crystalline phase, improving the mechanical strength of the material, and improving chemical durability. The ZrO2 content is preferably 5% or more, more preferably 5.5% or more, even more preferably 6.0% or more, even more preferably 6.5% or more, particularly preferably 7.0% or more, even more preferably 7.5%, and most preferably 8.0% or more, from the viewpoint of stably precipitating indialite / cordierite crystals. Furthermore, the ZrO2 content is preferably 15% or less, more preferably 14.5% or less, even more preferably 14% or less, even more preferably 13.5% or less, particularly preferably 13% or less, even more preferably 12.5% ​​or less, and most preferably 12% or less, from the viewpoint of increasing the proportion of indialite / cordierite crystals in the entire crystallized glass and improving dielectric properties.

[0041] The present crystallized glass preferably contains a vacancy-generating component. The vacancy-generating component refers to a component that facilitates the formation of at least one of the aforementioned portions where no Al atoms are present, i.e., portions containing vacancies and foreign elements, at the Al sites of the indialite / cordierite crystals. Examples of vacancy-generating components include P2O5 and B2O3. Of these, P2O5 is a component that facilitates the formation of many vacancies and portions containing foreign elements at the Al sites of the indialite / cordierite crystals, and is therefore particularly preferred as a vacancy-generating component.

[0042] The reason why the inclusion of a vacancy-generating component facilitates the formation of vacancies or portions containing heterogeneous elements at the Al site is thought to be as follows. Specifically, vacancy-generating components, such as P2O5, cause microphase separation during the crystallization process in which amorphous glass is heated. When indialite / cordierite crystals grow, the crystals grow from each of the interfaces of these microphase separations, improving the dispersion of the crystals in the crystallized glass and facilitating the formation of homogeneous crystals. This makes it easier for atoms around the Al site to compete for Al atoms during crystal growth. This makes the Al site more likely to become vacant or to incorporate heterogeneous elements such as Mg. Furthermore, when a portion without Al atoms is formed at the Al site by adding a vacancy-generating component, this portion is more likely to contain vacancies, and is thought to be more likely to have more vacancies than a portion containing heterogeneous elements.

[0043] The content of the vacancy-generating component is preferably 0.5% or more, more preferably 1% or more, even more preferably 2% or more, and even more preferably 3% or more, from the viewpoint of facilitating the formation of portions where no Al atoms exist at Al sites. On the other hand, from the viewpoint of suppressing separation between the crystalline phase and the glass phase and stably precipitating crystals, the content of the vacancy-generating component is preferably 15% or less, more preferably 7.5% or less, and even more preferably 3.5% or less.

[0044] Although P2O5 is not an essential component, it is preferably contained because it functions as the void-generating component described above. In addition to its function as a void-generating component, P2O5 also contributes to improving the meltability, formability, and devitrification resistance of glass raw materials. When P2O5 is contained, the content is preferably 0.5% or more, more preferably 0.75% or more, even more preferably 1% or more, even more preferably 1.25% or more, particularly preferably 1.5% or more, even more preferably 1.75%, and most preferably 2% or more, from the viewpoint of facilitating the formation of regions where no Al atoms are present at Al sites. Furthermore, from the viewpoint of suppressing separation between the crystalline phase and the glass phase and stably precipitating crystals, the content of P2O5 is preferably 15% or less, more preferably 13% or less, even more preferably 11% or less, even more preferably 9% or less, particularly preferably 7% or less, even more preferably 5% or less, and most preferably 3.5% or less.

[0045] Although B2O3 is not an essential component, it may be contained because it functions as the above-mentioned vacancy-generating component. B2O3 also contributes to adjusting the viscosity during melting and molding of glass raw materials and to the crystallization temperature. From the viewpoint of facilitating the formation of regions where no Al atoms exist at Al sites, the B2O3 content is preferably 0.5% or more, more preferably 0.75% or more, even more preferably 1% or more, even more preferably 1.25% or more, particularly preferably 1.5% or more, even more preferably 1.75%, and most preferably 2% or more. On the other hand, from the viewpoint of suppressing an excessive decrease in viscosity at crystallization and stably producing glass, the B2O3 content is preferably 10% or less, more preferably 9% or less, even more preferably 8% or less, even more preferably 7% or less, particularly preferably 6% or less, even more preferably 5% or less, and most preferably 4% or less.

[0046] Furthermore, when both P2O5 and B2O3 are added, the total amount is preferably 1% or more from the viewpoint of facilitating the formation of a region where no Al atoms exist at the Al site, and the total amount is preferably 15% or less from the viewpoints of suppressing separation between the crystalline phase and the glass phase and stably precipitating crystals.

[0047] Although CaO may not be contained, it has the effect of improving the meltability of the glass raw material and simultaneously preventing the coarsening of the precipitated crystal phase, so it may be contained in an amount of 4% or less. The CaO content is more preferably in the range of 1% or more. Furthermore, the CaO content is more preferably in the range of 3% or less.

[0048] BaO may not be contained, but may be contained in an amount of 5% or less to improve the meltability of the glass raw material. The BaO content is more preferably in the range of 1% or more. The BaO content is more preferably in the range of 3% or less.

[0049] Sb2O3 and As2O3 do not necessarily have to be contained, but may be contained in an amount of 1% or less because they act as fining agents when the glass raw materials are melted.

[0050] F does not necessarily have to be contained, but may be contained in an amount of 3% or less in order to improve the meltability of the glass raw material.

[0051] SnO2, CeO, and Fe2O3 do not necessarily need to be contained, but may be contained in a total of 5% or less of each component as a glass colorant or to improve the sensitivity of detecting surface defects by coloring the glass, and to improve the absorption characteristics of LD-pumped solid-state lasers.

[0052] (Physical Properties) From the viewpoint of improving dielectric properties, the dielectric loss tangent of this crystallized glass at 20°C and 10GHz is preferably 0.003 or less, more preferably 0.002 or less, even more preferably 0.0018 or less, even more preferably 0.0016 or less, particularly preferably 0.0014 or less, even more preferably 0.0012 or less, particularly preferably 0.001 or less, and most preferably 0.0008 or less. The dielectric loss tangent at 20°C and 10GHz is preferably smaller, but is usually 0.0001 or more.

[0053] From the viewpoint of improving the dielectric properties, the relative dielectric constant of the present crystallized glass at 20°C and 10 GHz is preferably 7 or less, more preferably 6.5 or less, and even more preferably 6 or less. The smaller the relative dielectric constant at 20°C and 10 GHz, the better, but it is usually 4.0 or more.

[0054] This glass-ceramic has excellent dielectric properties due to its relatively high content of indialite / cordierite crystals. If the dielectric loss tangent or dielectric constant at 20°C and 10 GHz is within the preferred ranges described above, the glass-ceramic is also expected to have excellent dielectric properties in the frequency range above 10 GHz. The dielectric properties, such as the dielectric loss tangent and dielectric constant, are measured using slip post dielectric resonance (SPDR) techniques.

[0055] The thermal conductivity of this glass-ceramics at 20°C is preferably 1.0 W / (m·K) or higher, more preferably 1.5 W / (m·K) or higher, even more preferably 2.0 W / (m·K) or higher, even more preferably 2.5 W / (m·K) or higher, and particularly preferably 3.0 W / (m·K) or higher, from the viewpoint of efficient heat dissipation when used as a high-frequency substrate. Thermal conductivity can be measured using a laser flash thermal property measurement device according to the method specified in JIS R1611 (2010). While a higher thermal conductivity is preferable, it is usually 8.0 W / (m·K) or lower. Thermal conductivity can be adjusted by adjusting the crystal content, crystal species, and crystal precipitation form. Thermal conductivity is particularly closely correlated with the degree of crystallization. While uncrystallized glass generally has a thermal conductivity of 1.0 W / (m·K) or lower, it is known that crystallized samples have improved thermal conductivity.

[0056] The average thermal expansion coefficient of the present crystallized glass at 50 to 350 ° C is preferably 1 ppm / ° C or more, more preferably 1.5 ppm / ° C or more, even more preferably 1.75 ppm / ° C or more, particularly preferably 2.0 ppm / ° C or more, even more preferably 2.25 ppm / ° C or more, and most preferably 2.5 ppm / ° C or more, from the viewpoint of reducing the difference in thermal expansion coefficient with other components when the present crystallized glass is used in bonding with other components. In addition, the average thermal expansion coefficient at 50 to 350 ° C is preferably 8.0 ppm / ° C or less, more preferably 7.0 ppm / ° C or less, and even more preferably 6.0 ppm / ° C or less, from the viewpoint of reducing the difference in thermal expansion coefficient with other components, reducing the difference in thermal expansion coefficient between crystal and glass, and suppressing cracking of the crystallized glass. The average thermal expansion coefficient at 50 to 350 ° C can be measured using a differential thermal dilatometer according to the method specified in JIS R3102 (1995). The average thermal expansion coefficient can be adjusted by the glass composition, crystalline content, etc. Furthermore, since the present crystallized glass is prevented from cracking due to the difference in thermal expansion coefficient between the crystalline phase and the glass phase, it is easy to increase the average thermal expansion coefficient to a certain extent.

[0057] (shape) The shape of the present crystallized glass is not particularly limited, and can be various shapes depending on the purpose and use. For example, the present crystallized glass may be a plate-like shape with two main surfaces facing each other, or may be a shape other than a plate-like shape depending on the product to be applied, the use, etc. More specifically, the present crystallized glass may be, for example, a flat glass plate without warping, or a curved glass plate with a curved surface. The shape of the main surface is also not particularly limited, and can be formed into various shapes such as a circle or a rectangle.

[0058] A preferred shape of the present crystallized glass is, for example, a glass having two mutually opposing main surfaces with an area of ​​100 to 100,000 cm. 2 The thickness may be 0.01 to 2 mm.

[0059] The area of ​​the main surface of this crystallized glass is 100cm2 from the viewpoint of transmission and reception efficiency when used in an antenna, etc. 2 More than 225cm is preferable. 2More than 400cm is preferable. 2 More preferably, the area of ​​the main surface is 100,000 cm from the viewpoint of handling. 2 Preferably below 10000cm 2 Less than 3600cm is more preferable. 2 The following is even more preferred:

[0060] In addition, the thickness of the present crystallized glass is preferably 0.01 mm or more from the viewpoint of maintaining strength, more preferably 0.05 mm or more, and even more preferably 0.1 mm or more.The thickness of the present crystallized glass is preferably 2 mm or less, more preferably 1 mm or less, and even more preferably 0.7 mm or less from the viewpoint of thinning and miniaturization of parts and products using the present crystallized glass, and improving production efficiency.

[0061] (Application) This glass-ceramics is suitable for substrates for high-frequency devices (electronic devices), such as semiconductor devices used in communication equipment such as mobile phones, smartphones, personal digital assistants, and Wi-Fi devices, circuit boards for surface acoustic wave (SAW) devices, radar components such as radar transceivers, and antenna components such as liquid crystal antennas. This glass-ceramics has excellent dielectric properties, particularly in the high-frequency range, and is inhibited from cracking due to the difference in thermal expansion coefficient between the crystalline phase and the glass phase, and also has excellent thermal shock resistance, making it suitable for high-frequency substrates used in high-frequency devices and liquid crystal antennas.

[0062] <High frequency substrate> The present crystallized glass has excellent dielectric properties at high frequencies and excellent thermal shock resistance, so it can be used for high frequency substrates. The preferred ranges of the relative permittivity, dielectric loss, thermal conductivity and average thermal expansion coefficient of the high frequency substrate according to this embodiment using the present crystallized glass (hereinafter also referred to as the present high frequency substrate) are the same as those of the present crystallized glass.

[0063] A high frequency substrate generally has two main surfaces facing each other. The area of ​​the main surfaces of this high frequency substrate is 75 cm2 from the viewpoint of transmission and reception efficiency. 2 More preferably, 100 cm2 More than 150cm, more preferably 2 More preferably, 300 cm 2 More than 600cm, especially preferred 2 The area of ​​the main surface of this high frequency substrate is 5000cm2 to ensure strength. 2 The following are preferable. The shape can be freely designed according to the purpose as long as it has the above area.

[0064] The thickness of the high frequency substrate is preferably 1 mm or less, more preferably 0.8 mm or less, and even more preferably 0.7 mm or less. A thickness within this range is preferred because it allows the entire substrate to be made thinner when stacking substrates to form a circuit. On the other hand, a thickness of 0.05 mm or more, more preferably 0.2 mm or more, ensures strength.

[0065] When the present glass-ceramics is used as a high-frequency substrate material, holes may be formed in the glass-ceramics substrate made of the present glass-ceramics. That is, the present high-frequency substrate may have holes with openings on at least one of its main surfaces. The holes may be through-holes that communicate with the other main surface, or they may be blind voids. These holes may be filled with conductors or conductive films may be formed on the hole walls, allowing them to be used as circuits.

[0066] The diameter of the pores is, for example, 200 μm or less, preferably 100 μm or less, and more preferably 50 μm or less, while the diameter of the pores is preferably 1 μm or more.

[0067] The method for forming holes is not particularly limited, but for example, a method of irradiating a crystallized glass substrate with a laser is suitable for accurately forming small holes with a diameter of 200 μm or less. Substrates using this crystallized glass have excellent processability by laser irradiation. The wavelength of the laser is not particularly limited, but for example, 10.6 μm or less, 3000 nm or less, 2050 nm or less, 1090 nm or less, 540 nm, or 400 nm or less is used. In particular, when forming small holes with a diameter of 100 μm or less, the following two methods are suitable.

[0068] (Processing with UV laser) Holes are formed in the crystallized glass substrate by irradiating it with a UV laser having a wavelength of 400 nm or less. The UV laser is preferably pulsed, and an absorption layer is preferably provided on the surface of the crystallized glass substrate during laser irradiation. After laser irradiation, the crystallized glass substrate may be etched with a solution containing hydrofluoric acid to enlarge the holes.

[0069] (Processing by forming modified parts) A modified portion is formed in the crystallized glass substrate by irradiating it with a laser having a wavelength of 400 to 540 nm, for example, a wavelength of approximately 532 nm. The crystallized glass substrate is then etched with a solution containing hydrofluoric acid to selectively remove the modified portion and form a hole. This method uses pulsed oscillation of a laser or the like, and can form the modified portion with just one shot of pulse irradiation, resulting in a fast hole formation speed and excellent productivity.

[0070] <Antenna for LCD> An LCD antenna is a satellite communication antenna that uses LCD technology to control the direction of radio waves it transmits and receives, and is primarily suitable for use on vehicles such as ships, airplanes, and automobiles. Because LCD antennas are primarily intended for outdoor use, they must have stable characteristics over a wide temperature range, and must also be resistant to thermal shock caused by sudden temperature changes, such as between the ground and the sky, or during a rain shower in a scorching desert.

[0071] The present crystallized glass has excellent dielectric properties at high frequencies and excellent thermal shock resistance, so it can be used for liquid crystal antennas. The preferred ranges of the relative permittivity, dielectric loss, thermal conductivity, and average thermal expansion coefficient of the liquid crystal antenna according to this embodiment (hereinafter also referred to as the present liquid crystal antenna) using the present crystallized glass are the same as those of the present crystallized glass.

[0072] The LCD antenna generally has two opposing main surfaces. The area of ​​the main surfaces of this LCD antenna is 75cm2 from the viewpoint of transmission and reception efficiency. 2 More preferably, 100 cm 2More than 150cm, more preferably 2 More preferably, 300 cm 2 More than 700cm, especially preferred 2 The area of ​​the main surface of this LCD antenna is 10,000 cm from the viewpoint of ease of handling. 2 Preferably below 3600cm 2 Less than 2500cm is more preferable. 2 The following is even more preferable: The shape can be freely designed according to the purpose as long as it has the above-mentioned area.

[0073] The plate thickness of the present liquid crystal antenna is preferably 1 mm or less, more preferably 0.8 mm or less, and even more preferably 0.7 mm or less. A plate thickness within the above range is preferable because the entire plate can be made thin. On the other hand, a plate thickness of preferably 0.05 mm or more, more preferably 0.2 mm or more, can ensure strength.

[0074] <Method of manufacturing glass-ceramics> Next, the method for producing the present crystallized glass (hereinafter also referred to as the present production method) will be described. The method for producing the present crystallized glass is not particularly limited, but for example, the following method is preferable. Below, the method for producing plate-shaped glass will be described, but the shape of the glass can be appropriately adjusted depending on the purpose.

[0075] This manufacturing method includes preparing amorphous glass containing, expressed as oxide-based mass percentages, 45-60% SiO2, 20-35% Al2O3, and 9-15% MgO (amorphous glass forming step), and heat-treating the amorphous glass (crystallization step). This manufacturing method also includes precipitating crystals of at least one of indialite and cordierite in the heat treatment and causing vacancies and at least one of a different element to exist at the Al sites of the crystals. Each step will be described in detail below.

[0076] (Amorphous glass forming process) In this process, raw materials prepared to obtain the desired glass composition are melted and formed into amorphous glass. The melt-forming method is not particularly limited, but the prepared glass raw materials are placed in a platinum crucible and then placed in an electric furnace at 1300°C to 1700°C to melt, degas, and homogenize. The resulting molten glass is poured into a metal mold (e.g., a stainless steel surface plate) at room temperature, held at the glass transition temperature for approximately 3 hours, and then cooled to room temperature to obtain a glass block of amorphous glass. The resulting glass block is then cut, ground, polished, or otherwise processed as needed to form the desired shape. Cutting, grinding, polishing, and other processes may be performed after the crystallization process. When the amorphous glass is processed before the crystallization process, the shape is not particularly limited, and preferred shapes are the same as those of the present crystallized glass.

[0077] As described above, amorphous glass can be formed into a desired shape from a molten state. This gives it advantages over processes such as ceramics, which are formed from powder or slurry and then fired, or synthetic quartz, which are formed from an ingot and then cut into a desired shape, in that it is easy to form and produce a large area. Furthermore, in view of the crystallization process described below, amorphous glass can be produced inexpensively.

[0078] From the viewpoint of precipitating at least one of indialite and cordierite crystals in the glass-ceramics, the amorphous glass preferably contains 45-60% SiO2, 20-35% Al2O3, and 9-15% MgO. The amorphous glass also preferably contains 5-15% TiO2 as a nucleating agent. The amorphous glass also preferably contains 0.5-15% P2O5 as a void-generating component. The preferred composition of the amorphous glass is the same as the preferred composition of the present glass-ceramics described above in <Glass-ceramics>, and the details are the same as those described above.

[0079] (crystallization process) Next, the amorphous glass obtained in the amorphous glass forming step is heat-treated. In the heat treatment, it is preferable to hold the amorphous glass at a specific treatment temperature for a specific holding time, and the treatment temperature and holding time are not particularly limited as long as they are conditions that allow at least one of indialite and cordierite crystals to precipitate and allow at least one of vacancies and heterogeneous elements to exist at the Al sites of the crystals.

[0080] This manufacturing method is characterized in that at least one of indialite and cordierite crystals is precipitated in the heat treatment, and at least one of vacancies and a different element is present at the Al site of the crystals. The method for creating vacancies and / or a different element at the Al site is not particularly limited. For example, by including a vacancy-generating component such as P2O5 in the composition and creating a minute phase separation region in the glass in the first temperature range described below, it becomes easier to create regions where no Al atoms exist at the Al site. Rapidly increasing the temperature during heat treatment also makes it easier to create regions where no Al atoms exist at the Al site. These methods may be used alone or in combination.

[0081] Specific preferred conditions for the heat treatment will be described below.

[0082] From the viewpoints of promoting the precipitation of indialite / cordierite crystals and shortening the heat treatment time to increase productivity, the treatment temperature is preferably, for example, 960°C or higher, more preferably 980°C or higher, and even more preferably 1000°C or higher. On the other hand, from the viewpoints of suppressing the precipitation of crystals other than indialite / cordierite and manufacturability, the treatment temperature is preferably 1350°C or lower, more preferably 1250°C or lower, and even more preferably 1150°C or lower.

[0083] The holding time is preferably 0.5 hours or more, more preferably 1 hour or more, even more preferably 1.5 hours or more, even more preferably 2 hours or more, particularly preferably 2.5 hours or more, and most preferably 3 hours or more. When the holding time is within the above range, crystallization proceeds sufficiently. On the other hand, since a long heat treatment time increases the cost of the heat treatment, the holding time is preferably 15 hours or less, more preferably 12 hours or less, and particularly preferably 10 hours or less.

[0084] The heat treatment preferably includes maintaining the above treatment temperature, but may further include increasing and decreasing the temperature within the above treatment temperature range or within another temperature range. Specifically, for example, the temperature may be raised from room temperature to a first temperature range and maintained for a certain period of time, and then slowly cooled to room temperature. Alternatively, a two-stage heat treatment may be selected in which the temperature is raised from room temperature to the first temperature range and maintained for a certain period of time, then maintained in a second temperature range that is higher than the first temperature range for a certain period of time, and then slowly cooled to room temperature.

[0085] The heat treatment preferably includes a two-stage heat treatment, including holding in a first temperature range and holding in a second temperature range, particularly when the composition contains a nucleation component or a vacancy-generating component. In the two-stage heat treatment, holding in the first temperature range allows the nucleation component in the amorphous glass to generate nuclei that serve as starting points for the growth of indialite / cordierite crystals. Then, holding in the second temperature range allows indialite / cordierite crystals to grow from these nuclei. Although indialite / cordierite crystals grow even in a single-stage heat treatment, generating nuclei and then growing the crystals facilitates the homogeneous distribution of crystals in the crystallized glass, making it easier to form areas where Al atoms are absent at the Al site. Furthermore, when the amorphous glass contains a vacancy-generating component, the vacancy-generating component causes microphase separation during the heat treatment, allowing crystals to grow from the interface of this phase separation, making it easier to form areas where Al atoms are absent at the Al site.

[0086] In the case of a two-stage heat treatment, the first temperature range is preferably a temperature range in which the crystal nucleation rate is high for the glass composition. Specifically, the first temperature range is preferably 760°C or higher, more preferably 800°C or higher, and even more preferably 850°C or higher. The first temperature range is also preferably 960°C or lower, more preferably 920°C or lower, and even more preferably 880°C or lower.

[0087] The holding time in the first temperature range is preferably 0.5 hours or more, more preferably 1 hour or more, more preferably 1.5 hours or more, and particularly preferably 2 hours or more. When the holding time is within the above range, nucleation is likely to proceed sufficiently. On the other hand, from the viewpoint of suppressing the progress of crystal growth simultaneously with nucleation and from the viewpoint of improving the dielectric properties of the entire crystallized glass, the holding time is preferably 5 hours or less, more preferably 4 hours or less, and particularly preferably 3 hours or less.

[0088] The second temperature range is preferably a temperature range in which the crystal growth rate of indialite / cordierite crystals is high. Specifically, the second temperature range is preferably 960°C or higher, more preferably 980°C or higher, and even more preferably 1000°C or higher. The second temperature range is also preferably 1350°C or lower, more preferably 1250°C or lower, and even more preferably 1150°C or lower.

[0089] The retention time in the second temperature range is preferably 0.5 hours or more, more preferably 1 hour or more, even more preferably 1.5 hours or more, even more preferably 2 hours or more, particularly preferably 2.5 hours or more, and most preferably 3.0 hours or more. When the retention time is within the above range, crystal growth tends to proceed sufficiently. On the other hand, from the viewpoint of manufacturability, the retention time is preferably 15 hours or less, more preferably 14 hours or less, and particularly preferably 12 hours or less.

[0090] The temperature rise rate in the heat treatment is not particularly limited, but is generally 5°C / min or more. From the viewpoint of increasing the temperature rise rate to cause at least one of vacancies and heterogeneous elements to exist at the Al sites, the temperature rise rate is preferably 15°C / min or more, and more preferably 20°C / min or more. On the other hand, if the temperature rise rate is preferably 30°C / min or less, and more preferably 25°C / min or less, cracking due to the difference in expansion coefficient between the glass phase and the crystalline phase that occurs during temperature rise can be suppressed.

[0091] The cooling rate is not particularly limited, but is preferably 10°C / min or less, more preferably 5°C / min or less, and even more preferably 1°C / min or less, so that warping of the crystallized glass and cracking due to the difference in expansion coefficient between the amorphous phase and the crystalline phase can be suppressed during cooling. On the other hand, the cooling rate is generally 0.5°C / min or more. [Example]

[0092] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these. Examples 1 to 8, 11 to 13, and 15 to 18 are working examples, and Examples 9, 10, and 14 are comparative examples.

[0093] Glass raw materials were mixed to obtain the composition shown in Table 1, expressed as mole percentages based on oxides, and weighed out to give 400 g of glass. The mixed raw materials were then placed in a platinum crucible and placed in an electric furnace at 1500-1700°C, where they were melted for approximately 3 hours, degassed, and homogenized. Table 2 also lists the components shown in Table 1 in terms of mass percentages.

[0094] The resulting molten glass was poured into a metal mold and held at a temperature approximately 50°C higher than the glass transition point for 1 hour, then cooled to room temperature at a rate of 0.5°C / min to obtain a glass block. The resulting glass block was cut and ground, and finally both sides were mirror-polished to obtain Glasses 1 to 12 as 40mm x 40mm, 2mm thick glass plates.

[0095] The obtained glass was subjected to a heat treatment as shown in Figure 1. Figure 1 is a diagram showing the temperature change in the two-stage heat treatment. Specifically, Figure 1 shows that in the heat treatment, the amorphous glass is heated to a temperature T1 at a first heating rate and held at that temperature for a holding time t1, then heated to a temperature T2 at a second heating rate and held at that temperature for a holding time t2, and then cooled.

[0096] Glass-ceramics were obtained by carrying out the heat treatment under the specific conditions such as temperature of the heat treatment in Figure 1 as shown in Table 3. The physical properties listed in Table 3 were obtained from the obtained glass-ceramics. In Table 3, a blank "-" in the "Crystallization Conditions" column indicates that heat treatment under the corresponding conditions was not carried out, and a blank "-" in the "Properties" column indicates that the corresponding physical property was not measured.

[0097] The methods for measuring each physical property are shown below.

[0098] (XRD measurement, Rietveld analysis) (XRD measurement sample preparation conditions) The heat-treated crystallized glass plate was crushed using an agate mortar and agate pestle to obtain a powder for XRD measurement.

[0099] (XRD measurement conditions) X-ray diffraction was measured under the following conditions to identify the precipitated crystals. The crystal species were identified using the diffraction peak patterns recorded in the ICSD inorganic crystal structure database and the ICDD powder diffraction database. Measurement equipment: Rigaku SmartLab Measurement method: Concentration method Tube voltage: 45kV Tube current: 200mA X-ray used: CuKα ray Measurement range: 2θ=10°~80° Speed: 10° / min Step: 0.02°

[0100] (Rietveld measurement sample preparation conditions) The crystallized glass powder used for the XRD measurement was passed through a mesh with an opening of 500 μm, and then ZnO was added as a standard substance so that it accounted for 10 wt % of the total sample.

[0101] (Rietveld analysis conditions) Powder X-ray diffraction was measured under the following conditions, and the results were used for Rietveld analysis. Measurement equipment: SmartLab manufactured by Rigaku Corporation Measurement method: Concentration method Tube voltage: 45kV Tube current: 200mA X-ray used: CuKα ray Measurement range: 2θ=10°~90° Speed: 5° / min Step: 0.01°

[0102] The powder X-ray diffraction profiles obtained under the above conditions were analyzed using the Rietveld analysis program: Rietan FP. The analysis of each sample was converged so that Rwp, which indicates the quality of convergence of the analysis, was 10 or less. The Rietveld method is described in "Crystal Analysis Handbook," edited by the Editorial Committee of the Crystallographic Society of Japan (Kyoritsu Shuppan, 1999, pp. 492-499).

[0103] (Calculation of crystallization rate) The content (crystallization rate) of indialite / cordierite crystals in the crystallized glass was calculated by subtracting the 10 wt% ZnO added from the weight ratio of the crystalline phase obtained by Rietveld analysis and the remaining glass phase obtained by subtracting the crystalline phase content from the total amount of the measured sample, so that the remaining phase totaled 100 wt%. In Table 3 below, "total amount of indialite / cordierite crystals" refers to the percentage (mass%) of the total content of indialite / cordierite crystals.

[0104] (Calculation of porosity) The atomic occupancy of Al obtained by Rietveld analysis was used to calculate the vacancy rate, that is, the total ratio (atom %) of the portion where no Al atoms existed to the Al site.

[0105] (average thermal expansion coefficient) Measurements were performed using a differential thermal dilatometer according to the method specified in JIS R3102 (1995). The measurement temperature range was 50 to 350°C, and the unit was expressed in ppm / °C. The sample used was a heat-treated crystallized glass plate cut into a circular (cylindrical) shape with a diameter of 5 mm and a thickness of 20 mm.

[0106] (thermal conductivity) Measurements were performed using a laser flash thermal property measuring device (LFA-502 manufactured by Kyoto Electronics Manufacturing Co., Ltd.) according to the method specified in JIS R1611 (2010). The measurement temperature was 20°C. The sample used was a heat-treated crystallized glass plate cut into a circle with a diameter of 5 mm and a thickness of 1 mm.

[0107] (relative permittivity ε', dielectric tangent tanδ) The amorphous glass and crystallized glass were cut into rectangular parallelepipeds measuring 30.0 mm in length, 30.0 mm in width, and 0.5 mm in thickness, and the 30.0 mm × 30.0 mm surface was polished to a mirror finish. The dielectric constant ε' and dielectric loss tangent tanδ were measured at 20°C and 10 GHz using a network analyzer by slip post dielectric resonance (SPDR) method.

[0108] (Sample state) For each of the crystallized glasses of Examples 1 to 18, five samples were used and the fragility of the samples was evaluated according to the following criteria: When the sample was visually inspected and even a slight crack was found, the sample was judged to be broken. A: The number of cracks in the samples after heat treatment was one or less per five. B: The number of cracked samples after heat treatment was 2 to 3 out of 5 samples. C: The number of cracks in the samples after heat treatment was 4 or more out of 5.

[0109] [Table 1]

[0110] [Table 2]

[0111] [Table 3]

[0112] The crystallized glasses of Examples 1 to 8, 11 to 13, and 15 to 18, which were obtained using glasses 1 to 7 and 9 to 12, either did not break or were resistant to breakage after heat treatment, and the samples could be processed to measure their physical properties, with an indialite / cordierite crystal content of 40% by mass or more. The crystallized glass of Example 15 was less resistant to breakage than the crystallized glasses of Examples 11 to 13. Therefore, in Table 3, the condition of the sample of Example 15 was rated B+. In addition, the crystallized glasses of Examples 2 to 4, 6, 7, and 12 had an indialite / cordierite crystal content of 40 mass% or more, an average linear thermal expansion coefficient of 1 ppm or more at 50 to 350°C, and a thermal conductivity of 1.0 W / (m·K) or more at 20°C. Furthermore, the crystallized glasses of Examples 2, 3, 4, 6, 7, 11, 12, 16, 17, and 18, which are working examples, have good values ​​of relative permittivity of 7 or less and dielectric loss tangent of 0.003 or less at 20°C and 10 GHz, and it was confirmed that they have good radio wave transmittance.

[0113] On the other hand, in the case of the crystallized glass of Example 9, the low heat treatment temperature prevented sufficient crystallization, resulting in a low crystallization rate. In the case of the crystallized glass of Example 10, the short heat treatment time prevented sufficient crystallization, resulting in a low crystallization rate. In the case of Example 14, the P content was too high, resulting in a low amount of indialite / cordierite crystals precipitated. In addition, in the crystallized glass of Example 14, many crystals other than indialite / cordierite crystals precipitated, resulting in the sample being prone to cracking after heat treatment.

[0114] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2020-157712) filed on September 18, 2020, the contents of which are incorporated herein by reference. [Industrial Applicability]

[0115] The crystallized glass of the present invention has excellent dielectric properties for high frequency signals and exhibits high thermal shock resistance. Such crystallized glass is extremely useful as a component for high-frequency electronic devices in general, such as high-frequency substrates that handle high-frequency signals exceeding 10 GHz, particularly high-frequency signals exceeding 30 GHz, and even high-frequency signals of 35 GHz or higher, as well as for liquid crystal antennas used in environments with large temperature changes, and for devices that involve hole drilling using lasers, etc.

Claims

1. Mass percentage based on oxides SiO ２ 45 to 60% Al ２ O ３ を20~35%、 MgO 9 to 15%, P ２ O ５ 0.5 to 15%, TiO ２ 5 to 15%, Amorphous glass containing.

2. Mass percentage based on oxides SiO ２ 45 to 60% Al ２ O ３ を20~35%、 MgO 9 to 15%, providing an amorphous glass containing A method for producing crystallized glass, comprising heat-treating the amorphous glass, The method for producing crystallized glass includes precipitating at least one of indialite and cordierite crystals in the heat treatment, and causing at least one of vacancies and a different element to exist at the Al site of the crystals.

3. The amorphous glass is Mass percentage based on oxides P ２ O ５ 0.5 to 15%, TiO ２ 5 to 15%, The method for producing crystallized glass according to claim 2, comprising:

4. The amorphous glass has two opposing main surfaces, and the areas of the main surfaces are 100 to 100,000 cm ２ 4. The method for producing crystallized glass according to claim 2, wherein the amorphous glass has a thickness of 0.01 to 2 mm.

5. 5. The method for producing crystallized glass according to claim 2, wherein the heat treatment comprises holding the amorphous glass at 960°C or higher for 0.5 hours or more.

6. the heat treatment includes holding in a first temperature range and holding in a second temperature range, the first temperature range being 760°C or higher and 960°C or lower, and the holding time in the first temperature range being 0.5 hours or longer; 5. The method for producing crystallized glass according to claim 2, wherein the second temperature range is 960° C. or higher and 1350° C. or lower, and the holding time in the second temperature range is 0.5 hours or longer.

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