Crystallized glass

Abstract

The present invention relates to crystallized glass which has a crystalline phase and contains, in molar percentages in terms of oxides, 55-72% of SiO2, 1.3-4.5% of Al2O3, 15-28% of Li2O, 0.5-5.0% of P2O5, and 0.5-4.4% of ZrO2, wherein: with respect to the total of SiO2, Al2O3, and Li2O, the ratio of SiO2 is 68.5-76.0%, the ratio of Al2O3 is 2.20-4.40%, and the ratio of Li2O is 23.0-28.5%; the content ratio of Li2Si2O5 crystal is 40 mass% or more; and the Poisson's ratio is 0.20 or more.

Description

Glass-ceramics

[0001] The present invention relates to glass-ceramics.

[0002] Thin, high-strength chemically strengthened glass is used as cover glass for displays of electronic devices such as mobile phones, smartphones, and other mobile equipment. Chemically strengthened glass is produced by bringing glass into contact with a molten salt composition such as sodium nitrate to cause ion exchange between alkali metal ions contained in the glass and alkali metal ions with a larger ionic radius contained in the molten salt composition, thereby forming a compressive stress layer from the surface to the interior of the glass.

[0003] As an index of the strength of such a cover glass, Young's modulus and fracture toughness value K ＩＣ Glass-ceramics have been attracting attention in order to realize high-strength cover glass with high values ​​for these properties. In particular, considering that chemical strengthening treatment is also performed, it is considered to apply Li-based glass-ceramics containing lithium to the cover glass.

[0004] Furthermore, the cover glass is required to have not only strength but also scratch resistance in order to prevent scratches from being formed on the surface during use.

[0005] For example, Patent Document 1 discloses that scratch resistance is improved by providing an optical thin film structure on a glass ceramic substrate. Patent Document 2 discloses that durability and scratch resistance are imparted by providing a low-reflection coating on a glass ceramic substrate. Patent Document 3 discloses that a glass-based material of a specific composition having a ceramic crystal layer containing mullite or β-quartz exhibits good scratch resistance.

[0006] Japanese Patent Application Publication No. 2024-513421 U.S. Patent Application Publication No. 2023 / 0280502 Japanese Patent No. 6925974

[0007] However, the glass disclosed in Patent Documents 1 and 2 is provided with scratch resistance, such as scratch resistance and mar resistance, by providing a layer other than the glass on the surface. In contrast, from the viewpoint of reducing manufacturing costs and simplifying the manufacturing process, it is desirable that the scratch resistance of the glass surface itself is good.

[0008] Therefore, crystallized glass having a crystalline phase is considered, but in Patent Document 3, the scratch resistance of glass-based materials containing crystallized glass such as mullite or β-quartz crystals is evaluated using Knoop-type diamond. However, the inventors' studies have found that tests using Knoop-type diamond do not adequately reproduce the scratches that occur when the cover glass is actually used. In other words, even if the scratch resistance is good, it does not necessarily mean that scratches can be suppressed under actual use conditions. Furthermore, compared to the strength of the glass-based materials described in Patent Document 3, higher strength is required for the cover glass.

[0009] In response to this, the present inventors have newly discovered that scratching tests using a conical diamond indenter with a 90-degree facing indenter angle can adequately reproduce scratches under actual use conditions. In other words, the scratch resistance of a cover glass under actual use conditions can be appropriately evaluated by such tests.

[0010] Therefore, an object of the present invention is to provide crystallized glass that has excellent scratch resistance and high strength under practical use environments.

[0011] To address the above issue, the fracture toughness value K ＩＣ In light of the fact that the index of brittleness, which is expressed as the ratio of surface hardness to surface hardness, is generally used, it is believed that scratch resistance can be improved by reducing brittleness, i.e., by increasing the fracture toughness value. However, the inventors' investigations have revealed that the above fracture toughness value K ＩＣFurther investigations have revealed that the Poisson's ratio of the crystallized glass is also important. By controlling the composition of the crystallized glass to a specific range, the Li content required to achieve high strength can be reduced. ２ Si ２ O ５ The inventors have found that it is possible to contain crystals at a certain ratio or more and to set the Poisson's ratio within a specific range, and have thus completed the present invention.

[0012] That is, the gist of this embodiment relates to the following: [1] A crystallized glass having a crystalline phase, wherein the composition of the crystallized glass is expressed in mole percentage based on oxides as follows: SiO ２ 55-72%, Al ２ O ３ 1.3-4.5%, Li ２ O 15-28%, P ２ O ５ 0.5 to 5.0%, and ZrO ２ 0.5 to 4.4%, and SiO ２ , Al ２ O ３ , and Li ２ Using the content ratio of O expressed as mole percentage, {[SiO ２ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O])} × 100 is 68.5 to 76.0%, ２ O ３ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O])} × 100 is 2.20 to 4.40%, and ２ O] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O])) × 100 is 23.0 to 28.5%, and the crystalline phase satisfies ２ Si ２ O ５The Li in the glass-ceramics is ２ Si ２ O ５ [2] A crystallized glass having a crystal content of 40 mass % or more and a Poisson's ratio of 0.20 or more. [2] The composition of the crystallized glass, expressed in mole percentage based on oxides, is: Na ２ O 0.1 to 5%, and K ２ [3] The glass-ceramics according to the above [1], further satisfying the following: Li 0 to 3%. ２ Si ２ O ５ The glass-ceramics according to [1] or [2], wherein the content of crystals other than crystals is 10% by mass or less. [4] The glass-ceramics according to any one of [1] to [3], wherein the glass-ceramics has an amorphous phase, and the content of the amorphous phase in the glass-ceramics is 20% by mass or more. [5] The fracture toughness value K ＩＣ (MPa m １／２ ) to the surface hardness Hv (HV) (surface hardness Hv / fracture toughness value K ＩＣ ) is 650 (HV / (MPa m １／２ [6] The crystallized glass according to any one of the above [1] to [4], wherein the fracture toughness value K ＩＣ is 1.2 MPa m １／２The crystallized glass according to any one of [1] to [5] above, wherein the scratch width is 60 μm or less when a scratch test is performed on the crystallized glass under the following conditions with a load of 0.6 N: Conditions: A conical diamond indenter with a 90-degree facing indenter angle is used as a scratching tip. The tip of the conical diamond indenter is pressed against the surface of the crystallized glass, and three scratches with a scratch length of 10 mm are formed at a speed of 1 mm / sec while applying a constant load. For each of the three scratches, the scratch widths of the three largest scratch widths are measured for a total of nine scratches, and the average value is taken as the scratch width. [8] The crystallized glass according to any one of [1] to [7] above, wherein the scratch width is 90 μm or less when a scratch test is performed on the crystallized glass under the following conditions with a load of 0.9 N: Conditions: A conical diamond indenter with a 90-degree indenter angle facing each other is used as the scratch terminal. The tip of the conical diamond indenter is pressed against the surface of the crystallized glass, and three scratches with a scratch length of 10 mm are formed at a speed of 1 mm / sec while applying a constant load. For each of the three scratches, the scratch widths of the three largest scratch points are measured for a total of nine scratches, and the average value is used as the scratch width. [9] The crystallized glass according to any one of [1] to [8] above, in which a scratch test is performed on the crystallized glass under the following conditions, applying a load of 1.2 N, and the scratch width is 120 μm or less. Conditions: A conical diamond indenter with a 90-degree indenter angle facing each other is used as the scratch terminal. The tip of the conical diamond indenter is pressed against the surface of the crystallized glass, and three scratches with a scratch length of 10 mm are formed at a speed of 1 mm / sec while applying a constant load. For each of the three scratches, measure the widths of the three largest scratches for a total of nine scratches, and use the average value as the scratch width.

[10] The glass-ceramics according to any one of [1] to [9] above, having a Young's modulus of 105 GPa or more.

[11] The glass-ceramics according to any one of [1] to

[10] above, having a haze value of 0.03 to 0.30% when converted to a thickness of 0.6 mm.

[12] The crystallized glass according to any one of [1] to

[11] , wherein the average crystallite size of the crystals constituting the crystalline phase is 20 to 200 nm.

[13] The crystallized glass according to any one of [1] to

[12] , wherein the surface layer has a compressive stress layer formed by ion exchange.

[0013] According to the present invention, it is possible to obtain crystallized glass that has excellent scratch resistance and high strength under practical use environments.

[0014] FIG. 1 shows the fracture toughness value K ＩＣ 2 is an explanatory diagram of a sample used for measuring the fracture toughness value K ＩＣ The stress intensity factor K1 (unit: MPa m １／２ 1 is a graph showing a K1-v curve showing the relationship between the crack propagation velocity v (unit: m / s) and the crack propagation velocity v (unit: m / s).

[0015] Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the embodiments described below. In this specification, the term "to" indicating a range of values ​​is used to mean that the values ​​before and after it are included as the lower and upper limits. In this specification, mass ratio and weight ratio, mass % and weight %, and parts by mass and parts by weight have the same meaning.

[0016] <<Ceramics>> The crystallized glass according to this embodiment has a crystalline phase, and the crystalline phase is Li ２ Si ２ O ５ The above Li crystals are included. ２ Si ２ O ５ The content of the crystals in the crystallized glass is 40 mass % or more.

[0017] The crystallized glass according to this embodiment is made of SiO ２ , Al ２ O ３ , and Li ２ SiO relative to the total content of O expressed in mole percentage ２ , Al ２ O ３ , and Li ２ The content ratio of each of the O is within the following ranges: ２] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O])} × 100 is 68.5 to 76.0%, ２ O ３ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O])} × 100 is 2.20 to 4.40%, and ２ O] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O])} × 100 is 23.0 to 28.5%.

[0018] In addition to the above, the composition of the crystallized glass according to this embodiment satisfies the following in terms of mole percentage based on oxides: SiO ２ 55-72%, Al ２ O ３ 1.3-4.5%, Li ２ O 15-28%, P ２ O ５ 0.5 to 5.0%, and ZrO ２ 0.5 to 4.4%.

[0019] In addition to the above, the crystallized glass according to this embodiment has a Poisson's ratio of 0.20 or more. By satisfying these, the crystallized glass according to this embodiment can achieve excellent scratch resistance and high strength in an actual use environment. As mentioned above, brittleness, which is a commonly used index for suppressing crack generation, is determined by the fracture toughness value K ＩＣ The ratio of the surface hardness Hv to the fracture toughness value K ＩＣ ) Then, in order to reduce the brittleness, the fracture toughness value K of the crystallized glass is ＩＣ However, the inventors' investigations have revealed that the above fracture toughness value K ＩＣ It was found that the improvement in scratch resistance was insufficient only by using the coating.

[0020] As a result of further investigation, it was discovered that scratch damage under actual use conditions can be suitably reproduced by a scratch test using a conical diamond indenter with an indenter angle of 90 degrees facing each other as a scratch terminal and a constant load method. Further investigation revealed that scratch damage under actual use conditions can be suitably reproduced by a constant load method using a conical diamond indenter with an indenter angle of 90 degrees facing each other as a scratch terminal. ＩＣ In addition, we have come to realize that the Poisson's ratio of the glass-ceramic is also important.

[0021] The fracture toughness value K ＩＣ Li ２ Si ２ O ５ The fracture toughness can be suitably increased by selectively containing a large amount of crystals, and for this purpose, it is important to satisfy a specific glass composition range. Furthermore, in order to make the Poisson's ratio a certain value or more, the glass composition of the crystallized glass is also important. On the other hand, the crystallized glass according to this embodiment satisfies the above composition, thereby achieving a suitable fracture toughness value K ＩＣ and Poisson's ratio can both be realized.

[0022] <Composition of crystallized glass> The composition of the crystallized glass according to this embodiment will be described in detail.In addition, the composition of crystallized glass in this specification is the same as the composition (mother composition) of amorphous glass (mother glass) before crystallization.In addition, the composition of the amorphous phase in crystallized glass can be obtained from the composition of crystallized glass and the composition and content ratio of the crystalline phase of crystallized glass.

[0023] The composition of the crystallized glass can be identified by a conventionally known method, for example, by wet chemical analysis or quantitative analysis using a fluorescent X-ray calibration curve.

[0024] Glass-ceramics can be determined to have a crystalline phase by observing diffraction peaks indicating crystals in an XRD pattern obtained by powder X-ray diffraction (XRD). The glass-ceramics have a crystalline phase in which crystals are precipitated by heat-treating amorphous glass (mother glass) in which no diffraction peaks indicating crystals are observed. The XRD measurement is performed using CuKα radiation in the 2θ range of 10° to 80°.

[0025] The composition and content of the crystalline phase in the crystallized glass can be determined by Rietveld analysis from the XRD pattern and diffraction intensity. 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). When the crystalline phase is composed of one type of crystal, the content of that crystal is the crystallinity, and when multiple crystals are present, the total content of those crystals is the crystallinity.

[0026] The composition of the crystallized glass according to this embodiment satisfies the following in terms of mole percentage based on oxides: SiO ２ 55-72%, Al ２ O ３ 1.3-4.5%, Li ２ O 15-28%, P ２ O ５ 0.5 to 5.0%, and ZrO ２ 0.5 to 4.4%.

[0027] In addition to the above, the composition of the crystallized glass is expressed in mole percentage based on oxides: Na ２ O 0.1 to 5%, and K ２ It is more preferable to further satisfy at least one of the above conditions, and it is even more preferable to further satisfy both of the above conditions.

[0028] The crystallized glass according to this embodiment contains SiO ２ , Al ２ O ３ , and Li ２ Using the content ratio of O expressed as mole percentage, {[SiO ２ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O])} × 100 is 68.5 to 76.0%, ２ O ３ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O])} × 100 is 2.20 to 4.40%, and２ O] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O])) × 100 is 23.0 to 28.5%.

[0029] Each component will be described below. The content of each component is expressed as mole percentage based on oxide unless otherwise specified.

[0030] SiO ２ is a component that constitutes the glass network, and Li ２ Si ２ O ５ It is also a component that forms crystals. SiO in crystallized glass ２ The content of Li is preferably 55 to 72%, more preferably 60 to 69%, and even more preferably 62 to 68%. ２ Si ２ O ５ From the viewpoint of facilitating crystal formation, the content is preferably 55% or more, more preferably 60% or more, even more preferably 62% or more, particularly preferably 64% or more, and most preferably 66% or more. ２ Si ２ O ５ From the viewpoint of facilitating crystal formation and enhancing the meltability of the glass, the content is preferably 72% or less, more preferably 70% or less, even more preferably 69.5% or less, still more preferably 69% or less, and particularly preferably 68% or less.

[0031] Al ２ O ３ is a component that improves ion exchangeability during chemical strengthening treatment and increases the surface compressive stress after chemical strengthening treatment. ２ O ３The content ratio is preferably 1.3 to 4.5%, more preferably 1.6 to 4.2%, and even more preferably 2.2 to 3.8%. Here, from the viewpoint of performing chemical strengthening treatment appropriately, the content ratio is preferably 1.3% or more, more preferably 1.6% or more, even more preferably 2.2% or more, may be 2.3% or more, may be 2.4% or more, may be 2.5% or more, or may be 2.6% or more. In addition, Li ２ Si ２ O ５ From the viewpoint of facilitating crystal formation, the content is preferably 4.5% or less, more preferably 4.2% or less, even more preferably 3.8% or less, may be 3.4% or less, may be 3.0% or less, may be 2.8% or less, or may be 2.6% or less.

[0032] Li ２ O is Li ２ Si ２ O ５ It is a component of crystals and is also a component that forms compressive stress near the surface of crystallized glass by ion exchange with Na ions. ２ The content of O is preferably 15 to 28%, more preferably 16 to 27%, and even more preferably 17 to 26%. ２ Si ２ O ５ From the viewpoint of facilitating crystal formation and increasing compressive stress, the content is preferably 15% or more, more preferably 16% or more, even more preferably 17% or more, even more preferably 18% or more, and particularly preferably 20% or more. ２ Si ２ O ５ From the viewpoint of facilitating crystal formation and the chemical durability of the glass, the content is preferably 28% or less, more preferably 27% or less, even more preferably 26% or less, and even more preferably 25% or less.

[0033] P ２ O ５ is a component that promotes crystallization. ２ O ５The content is preferably 0.5 to 5.0%, more preferably 0.8 to 4.5%, and even more preferably 0.9 to 3.0%. Here, from the viewpoint of facilitating crystallization, the content is preferably 0.5% or more, more preferably 0.7% or more, even more preferably 0.8% or more, and may be 0.9% or more, 1.0% or more, 1.1% or more, or 1.2% or more. Furthermore, from the viewpoint of suppressing phase separation during melting and a decrease in acid resistance, the content is preferably 5.0% or less, more preferably 4.5% or less, even more preferably 4.0% or less, even more preferably 3.0% or less, and particularly preferably 2.0% or less.

[0034] ZrO ２ is a thickening component that increases the viscosity when melted, and at the same time, is a component that increases the surface compressive stress due to ion exchange. ２ It has been found that by adding an appropriate amount of ZrO, it is possible to suitably control phase separation so that crystallization is facilitated while maintaining high transparency. As a result, when the glass is made into a crystallized glass, the crystallization degree can be increased while maintaining high transparency, and higher strength can be achieved. ２ The content ratio is preferably 0.5 to 4.4%, more preferably 1.0 to 4.2%, and even more preferably 1.5 to 4.0%. Here, from the viewpoint of controlling phase separation and acting as a thickening component to slow the growth rate of crystals that become crystalline phases and form fine crystals, thereby realizing higher transparency of the crystallized glass, the content ratio is preferably 0.5% or more, more preferably 1.0% or more, even more preferably 1.5% or more, and may be 1.6% or more, 1.8% or more, or 2.0% or more. Furthermore, from the viewpoint of suppressing devitrification during melting, the content ratio is preferably 4.4% or less, may be 4.2% or less, may be 4.0% or less, or may be 3.8% or less.

[0035] In addition, ZrO in the chemically strengthened glass according to this embodiment ２The content ratio is preferably 1 to 10 mass% when expressed as a mass percentage based on oxides. Here, from the viewpoint of controlling phase separation and acting as a thickening component to slow the growth rate of crystals that become crystalline phases and form fine crystals, thereby realizing higher transparency of the crystallized glass, the content ratio is preferably 1 mass% or more, more preferably 2.5 mass% or more, even more preferably 3.2 mass% or more, and even more preferably 3.7 mass% or more. Furthermore, from the viewpoint of suppressing devitrification during melting, the content ratio is preferably 10 mass% or less, more preferably less than 5 mass%, even more preferably 4.8 mass% or less, and may be 4.5 mass% or less, or may be 4.4 mass% or less.

[0036] Na ２ O is a component that forms compressive stress by ion-exchanging with K ions, and the inclusion of a small amount of O can increase the stability of the glass. ２ The content of O is preferably 0 to 5%, more preferably 0.1 to 5%, even more preferably 0.5 to 4.5%, even more preferably 1.0 to 4%, and particularly preferably 1.5 to 3.5%. ２ The content of O is 0%, that is, it may not be contained, but Na ２ When O is contained, from the viewpoint of increasing compressive stress and improving stability, the content is preferably 0.1% or more, more preferably 0.5% or more, even more preferably 1.0% or more, even more preferably 1.5% or more, or may be 2.0% or more, or may be 2.5% or more. Furthermore, from the viewpoint of maintaining chemical durability, the content is preferably 5% or less, more preferably 4.5% or less, even more preferably 4% or less, and even more preferably 3.5% or less.

[0037] K ２ O is a component that enhances chemical strengthening properties and suppresses phase separation. ２ The content of O is preferably 0 to 3%, more preferably 0.1 to 3%, and even more preferably 0.2 to 2%. ２ The content of O is 0%, that is, it may not be contained, but K ２When O is contained, the content is preferably 0.1% or more, more preferably 0.2% or more, and even more preferably 0.4% or more from the viewpoint of enhancing the stability of the glass, and is preferably 3% or less, more preferably 2% or less, and even more preferably 1% or less from the viewpoint of maintaining chemical durability.

[0038] SnO ２ is a fining agent during melting and also a component that generates crystal nuclei. ２ It has been found that the inclusion of SnO in the glass-ceramics can improve chemical resistance such as acid resistance and alkali resistance. ２ The content of SnO is preferably 0 to 1.00%, more preferably 0.01 to 1.00%, further preferably 0.01 to 0.50%, and even more preferably 0.05 to 0.40%. ２ may not be contained, but if contained, SnO ２ The content of acts as a component that generates the nucleus of crystal, and by forming minute crystals, from the viewpoint of realizing high transparency of crystallized glass and from the viewpoint of chemical resistance, the content is preferably 0.01% or more, more preferably 0.05% or more, even more preferably 0.10% or more, and can be 0.50% or more.In addition, from the viewpoint of suppressing the defects caused by unmelted matter, the content is preferably 1.00% or less, can be 0.50% or less, can be 0.40% or less.

[0039] The alkaline earth metals MgO, CaO, SrO, and BaO are components that enhance the meltability of glass. The total content of MgO, CaO, SrO, and BaO is preferably 0.0 to 5.0%, more preferably 0.1 to 4.0%, and even more preferably 0.5 to 3.0%. Although alkaline earth metals are not required, if they are contained, from the viewpoints of meltability and strength, the total content is preferably 0.1% or more, more preferably 0.2% or more, even more preferably 0.5% or more, and may even be 1.0% or more. Furthermore, from the viewpoint of maintaining good ion exchange performance, the total content is preferably 5.0% or less, more preferably 4.0% or less, even more preferably 3.0% or less, even more preferably 2.0% or less, and may even be 1.0% or less.

[0040] The respective contents of MgO, CaO, SrO, and BaO are preferably 0.0 to 4.0%, more preferably 0.1 to 3.0%, even more preferably 0.2 to 2.5%, even more preferably 0.5 to 2.0%, and particularly preferably 1.0 to 2.0%. MgO, CaO, SrO, and BaO may not be contained, but if they are contained, from the viewpoint of enhancing the stability of the glass, the respective contents are preferably 0.1% or more, more preferably 0.2% or more, even more preferably 0.5% or more, and even more preferably 1.0% or more. From the viewpoint of maintaining good ion exchange performance, the respective contents are preferably 4.0% or less, more preferably 3.0% or less, even more preferably 2.5% or less, and even more preferably 2.0% or less.

[0041] Y ２ O ３ Y is a thickening component that increases the viscosity during melting, and at the same time, it is a component that increases the mechanical strength of the glass. It is also a component that increases the refractive index. ２ O ３ The content of Y is preferably 0 to 5%, more preferably 0.1 to 3%, and even more preferably 0.3 to 1%. ２ O ３ Although it is not necessary to contain, when it is contained, it acts as a thickening component, slows down the growth rate of the crystal that becomes crystalline phase, and makes it into minute crystals, so that the high transparency of crystallized glass is realized, so that the content ratio is preferably 0.1% or more, more preferably 0.3% or more.In addition, from the viewpoint of suppressing devitrification during melting, the content ratio is preferably 5% or less, more preferably 3% or less, even more preferably 1% or less, even more preferably 0.5% or less, and can be 0.3% or less, or can be 0.1% or less.

[0042] HfO ２ is a component that enhances UV resistance. ２ The content of HfO is preferably 0 to 0.4%, more preferably 0.015 to 0.4%, and even more preferably 0.02 to 0.3%. ２ The content ratio of may be 0%, i.e., may not be contained, but HfO ２When containing, from the viewpoint of enhancing UV resistance, the content is preferably 0.015% or more, more preferably 0.02% or more, even more preferably 0.03% or more, and even more preferably 0.04% or more. Furthermore, from the viewpoint of preventing devitrification during melting, the content is preferably 0.4% or less, more preferably 0.3% or less, and even more preferably 0.2% or less.

[0043] TiO ２ is a thickening component that increases the viscosity when melted, and at the same time, is a component that increases UV resistance. ２ The content of TiO is preferably 0 to 5%, more preferably 0.1 to 3%, and even more preferably 0.5 to 1%. ２ Although it is not necessary to contain, when it is contained, it acts as a thickening component, slows down the growth rate of the crystals that become crystalline phase, and makes them into minute crystals, so that the high transparency of the crystallized glass can be realized, and the content ratio is preferably 0.1% or more, more preferably 0.5% or more. In addition, from the viewpoint of suppressing the decrease in haze value due to coloring, the content ratio is preferably 5% or less, more preferably 3% or less, and even more preferably 1% or less.

[0044] ZnO is a component that improves the meltability of glass. The ZnO content in the crystallized glass is preferably 0 to 5%, more preferably 0.1 to 4%, and even more preferably 0.2 to 1%. While ZnO need not be contained, if it is contained, from the viewpoint of obtaining good meltability, the content is preferably 0.1% or more, more preferably 0.5% or more, and even more preferably 1.0% or more. Furthermore, from the viewpoint of improving weather resistance, the content is preferably 5% or less, more preferably 4% or less, and even more preferably 1% or less, and may be 0.5% or less, or may be 0.1% or less.

[0045] B ２ O ３ is a component that improves chipping resistance and melting property. ２ O ３ The content of B is preferably 0 to 10%, more preferably 0.1 to 5%, and even more preferably 0.2 to 2%. ２ O ３Although it is not necessary to contain it, if it is contained, from the viewpoint of obtaining good chipping resistance and melting property, the content ratio is preferably 0.1% or more, more preferably 0.2% or more. Furthermore, from the viewpoint of suppressing the occurrence of striae and phase separation during melting and maintaining the quality of the crystallized glass, the content ratio is preferably 10% or less, more preferably 5% or less, and even more preferably 2% or less.

[0046] La ２ O ３ , Nb ２ O ５ and Ta ２ O ５ Is Y ２ O ３ Similarly to La, it has the effect of increasing the mechanical strength of the glass and may be contained to increase the refractive index. ２ O ３ , Nb ２ O ５ and Ta ２ O ５ The total content of these components is preferably 0 to 3%, more preferably 0.5 to 2%. These components do not necessarily have to be contained, but if they are contained, the total content is preferably 0.5% or more from the viewpoint of increasing the refractive index. Furthermore, the total content is preferably 3% or less, more preferably 2% or less from the viewpoint of suppressing devitrification of the glass during melting.

[0047] CeO ２ has the effect of oxidizing the glass, and the glass-ceramic becomes SnO ２ When the content is large, SnO ２ The reduction of CeO in glass-ceramics to SnO, which is a coloring component, can be suppressed, thereby suppressing coloration. ２ The content of CeO is preferably 0 to 1.5%, more preferably 0.03 to 1.5%, even more preferably 0.05 to 1%, and even more preferably 0.07 to 1%. ２ However, if it is contained, the content is preferably 0.03% or more, more preferably 0.05% or more, and even more preferably 0.07% or more, from the viewpoint of suppressing coloration due to SnO. ２From the viewpoint of suppressing coloration of the glass due to the presence of arsenic, the content is preferably 1.5% or less, and more preferably 1% or less.

[0048] Fe ２ O ３ is a component that enhances the melting property of glass. ２ O ３ The content of Fe is preferably 0 to 0.05%, more preferably 0.01 to 0.04%, and even more preferably 0.02 to 0.03%. ２ O ３ However, if it is contained, the content is preferably 0.01% or more, more preferably 0.02% or more, from the viewpoint of improving the meltability of the glass. Furthermore, the content is preferably 0.05% or less, more preferably 0.04% or less, and even more preferably 0.03% or less, from the viewpoint of the light transmittance of the glass.

[0049] Furthermore, a coloring component may be contained in the glass-ceramics to the extent that it does not hinder the achievement of the desired properties. ３ O ４ , MnO ２ , NiO, CuO, Cr ２ O ３ , V ２ O ５ , Bi ２ O ３ , SeO ２ , Er ２ O ３ , Nd ２ O ３ etc. The content ratio of the above coloring components in the crystallized glass is preferably in the range of 1% or less in total. Furthermore, if it is desired to increase the light transmittance of the crystallized glass, it is preferable that these components are not substantially contained. In this specification, "substantially not contained" means that the content is below the impurity level contained in raw materials, etc., that is, it is not intentionally added. In this specification, when it is stated that a certain component is not substantially contained, the content ratio of the component is specifically, for example, less than 0.01%.

[0050] In addition, SO is used as a fining agent when melting glass. ３, chloride, fluoride, As ２ O ３ , Sb ２ O ３ The content of each fining agent is preferably 0.3% or less, more preferably 0.1% or less, and most preferably substantially no fining agent is contained.

[0051] The composition of the crystallized glass according to this embodiment is SiO ２ , Al ２ O ３ , and Li ２ The values ​​expressed by the following formulas using the content ratio of O expressed in mole percentage are within the respective predetermined ranges: {[SiO ２ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O])} × 100 is 68.5 to 76.0%, ２ O ３ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O])} × 100 is 2.20 to 4.40%, ２ O] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O])} × 100 is 23.0 to 28.5%.

[0052] Each of the above formulas represents SiO ２ , Al ２ O ３ , and Li ２ SiO relative to the total content of O ２ , Al ２ O ３ , or Li ２ The content ratio of each component, such as O.

[0053] SiO ２ , Al ２ O ３ , and Li ２The total content of O means the total content ratio of components that easily form crystals in the crystallized glass. ２ 68.5 to 76.0%, Al ２ O ３ 2.20 to 4.40%, and Li ２ By containing 23.0 to 28.5% of O, Li ２ Si ２ O ５ The crystals are selectively precipitated, and a crystallized glass having a crystal content of 40 mass% or more and a Poisson's ratio of 0.20 or more is obtained. As a result, it has been found that the crystallized glass has excellent scratch resistance and high strength under practical use environments.

[0054] SiO relative to the total content ２ The content ratio of is 68.5 to 76.0%, preferably 69.0 to 74.5%. Here, the content ratio is 68.5% or more, and Li ２ Si ２ O ５ From the viewpoint of facilitating crystal formation and increasing the Poisson's ratio, the content is preferably 69.0% or more, more preferably 70.0% or more, and even more preferably 71.0% or more. ２ Si ２ O ５ From the viewpoint of facilitating crystal formation and enhancing the meltability of the glass, the content is preferably 74.5% or less, more preferably 73.0% or less, and even more preferably 71.5% or less.

[0055] Al content relative to the total content ２ O ３ The content ratio of is 2.20 to 4.40%, preferably 2.30 to 4.20%. Here, the content ratio is 2.20% or more, and from the viewpoint of suppressing phase separation during the production of amorphous glass and improving ion exchangeability during chemical strengthening treatment, it is preferably 2.30% or more, more preferably 2.40% or more, and even more preferably 2.50% or more. Furthermore, the content ratio is 4.40% or less, and SiO ２ , Al ２ O ３ , Li ２From the viewpoint of suppressing the precipitation of crystals composed of O and increasing the Poisson's ratio, the content is preferably 4.20% or less, more preferably 4.00% or less, even more preferably 3.80% or less, and even more preferably 3.60% or less.

[0056] Li relative to the total content ２ The content of O is 23.0 to 28.5%, preferably 23.5 to 28.3%. Here, the content is 23.0% or more, and Li ２ Si ２ O ５ From the viewpoint of facilitating crystal formation and increasing the Poisson's ratio, the content is preferably 23.5% or more, more preferably 24.0% or more, and even more preferably 25.0% or more. In addition, the content is 28.5% or less, and after the crystallization treatment, Li ２ SiO ３ From the viewpoint of suppressing residual crystals, the content is preferably 28.3% or less, more preferably 28.0% or less, and even more preferably 27.5% or less.

[0057] In addition, SiO in the crystallized glass ２ , Al ２ O ３ , and Li ２ The total content of O is preferably 90% or more, more preferably 90 to 96%. ２ Si ２ O ５ From the viewpoint of facilitating crystal formation, the total content is preferably 90% or more, more preferably 91% or more, even more preferably 92% or more, and even more preferably 93% or more. Also, from the viewpoint of improving ion exchangeability during chemical strengthening treatment, the total content is preferably 96% or less, even more preferably 95% or less, even more preferably 94% or less, and particularly preferably 93.5% or less.

[0058] Li of the crystallized glass according to this embodiment ２ O and ZrO ２ Using the content of {[Li ２ O] / [ZrO ２]} is preferably 8 or more, more preferably 8 to 20. Here, the value of the ratio serves as an index of Li ion exchange properties and alkali resistance. Among these viewpoints, from the viewpoint of improving the Li ion exchange properties, the value of the ratio is preferably 8 or more, more preferably 9 or more, even more preferably 11 or more, and particularly preferably 13 or more. Furthermore, from the viewpoint of improving the alkali resistance, the value of the ratio is preferably 20 or less, more preferably 17 or less, even more preferably 15 or less, and particularly preferably 14 or less.

[0059] The Al of the crystallized glass according to this embodiment ２ O ３ and ZrO ２ Using the content of {[Al ２ O ３ ] / [ZrO ２ The value of the ratio represented by {\displaystyle \mathbb {R}} is preferably 0.7 to 3.0. Here, the value of the ratio serves as an index of the K ion and Na ion exchange properties. From this viewpoint, the value of the ratio is preferably 0.7 or more, more preferably 0.8 or more, even more preferably 0.9 or more, even more preferably 1.0 or more, and particularly preferably 1.1 or more. Moreover, the value of the ratio is preferably 3.0 or less, more preferably 2.0 or less, even more preferably 1.5 or less, and even more preferably 1.2 or less.

[0060] <Crystalline Phase> The crystallized glass according to this embodiment has a crystalline phase of Li ２ Si ２ O ５ It has crystals. ２ Si ２ O ５ The content ratio of crystal in the crystallized glass is 40% by mass or more. Here, from the viewpoint of realizing higher strength and excellent scratch resistance, the content ratio is 40% by mass or more, preferably 50% by mass or more, more preferably 60% by mass or more. In addition, from the viewpoint of maintaining higher transparency and three-dimensional moldability, the content ratio is preferably 85% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less.

[0061] In this embodiment, the crystalline phase is Li ２ Si ２ O ５The crystals may further include other crystals, such as β-spodumene crystals (LiAlSi ２ O ６ ), petalite (LiAlSi ４ O １０ ), β-quartz (including bergerite) (Li ｘ Al ｘ Si ３－ｘ O ６ ), lithium metasilicate (Li ２ SiO ３ ), eucryptite (LiAlSiO ４ ), mullite (Al ４＋２ｘ Si ２－２ｘ O １０－ｘ , 0.2≦x≦0.5), lithium phosphate (Li ３ P.O. ４ ) and the like. In addition, the fracture toughness value K ＩＣ From the viewpoint of improving the properties, the content of petalite crystals in the crystallized glass is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 20% by mass or less, and may be 0% by mass, i.e., no petalite crystals may be contained. However, it is not limited to these and may be appropriately selected according to the desired properties.

[0062] For example, when it is desired to obtain a crystalline phase that can be ion-exchanged by chemical strengthening treatment, Li ２ Si ２ O ５ It may be composed of crystals only, but may also contain β-spodumene crystals, petalite, β-quartz, lithium metasilicate, and the like.

[0063] When it is desired to obtain a crystallized glass with higher strength, Li ２ Si ２ O ５ It may be composed of crystals only, but may also contain β-spodumene crystals, petalite, β-quartz, lithium metasilicate, mullite, etc.

[0064] If you want to achieve higher transparency, ２ Si ２ O ５ The material may be composed of crystals only, but may also contain β-quartz, lithium metasilicate, lithium phosphate, or the like.

[0065] In the crystallized glass according to this embodiment, the Li ２ Si ２ O ５ The content of crystals other than crystals is preferably 10% by mass or less, more preferably 0 to 10% by mass. ＩＣ The strength and scratch resistance of the crystallized glass depend on the amount of Li rather than the total amount of crystalline phase (crystallinity). ２ Si ２ O ５ It was found that the amount of crystalline phase was dominant. ２ Si ２ O ５ Because the strength of the crystal is superior to other crystals, Li ２ Si ２ O ５ It was found that the greater the content of the crystals, the higher the strength and scratch resistance. Therefore, from the viewpoint of further improving the strength and scratch resistance, the Li content of the crystallized glass was ２ Si ２ O ５ The total content of crystals other than the crystals is preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 5% by mass or less. The lower limit is not particularly limited, and it is possible to set the lower limit to 0% by mass, i.e., the total amount of the crystal phase is Li. ２ Si ２ O ５ It may be a crystal, and when it contains other crystals, it may be 1% by mass or more, or 2% by mass or more.

[0066] The content ratio of the crystalline phase in the crystallized glass according to this embodiment, i.e., the degree of crystallization, is not particularly limited. ２ Si ２ O ５ Since the content of crystals is 40% by mass or more, the crystallinity is also 40% by mass or more. The crystallinity may be 40 to 85% by mass, or 50 to 80% by mass. Here, the crystallinity may be 40% by mass or more, 50% by mass or more, 60% by mass or more, 85% by mass or less, 80% by mass or less, or 75% by mass or less. Note that the crystalline phase may contain Li. ２ Si２ O ５ When crystals other than the crystals are also contained, the total content of these crystals is the above-mentioned crystallinity.

[0067] In this embodiment, the average crystallite size of the crystals constituting the crystalline phase is preferably 20 to 200 nm. From the viewpoint of achieving higher strength, the average crystallite size is preferably 20 nm or more, more preferably 30 nm or more, and even more preferably 40 nm or more. From the viewpoint of achieving higher transparency, the average crystallite size is preferably 200 nm or less, more preferably 150 nm or less, and even more preferably 100 nm or less. The average crystallite size can be measured using powder X-ray analysis software (PDXL). The average crystallite size can also be adjusted by adjusting the heat treatment conditions for crystallization.

[0068] <Amorphous Phase> When the content of the crystalline phase, i.e., the degree of crystallization, of the crystallized glass according to this embodiment is not 100% by mass, the crystallized glass also has an amorphous phase. When the crystallized glass according to this embodiment has an amorphous phase, the content of the amorphous phase in the crystallized glass is preferably 20% by mass or more, and may be 20 to 40% by mass. From the viewpoint of increasing the Poisson's ratio, the content of the amorphous phase is preferably 20% by mass or more, more preferably 25% by mass or more, and even more preferably 30% by mass or more. Furthermore, from the viewpoint of increasing the strength of the crystallized glass, the content of the amorphous phase is preferably 40% by mass or less, more preferably 35% by mass or less, and may be 30% by mass or less.

[0069] <Characteristics and Physical Properties> The Poisson's ratio of the crystallized glass according to this embodiment is 0.20 or more, preferably 0.20 to 0.25. From the viewpoint of better scratch resistance, the Poisson's ratio is preferably 0.20 or more, more preferably 0.21 or more. From the viewpoint of better scratch resistance, the Poisson's ratio is preferably 0.25 or less, more preferably 0.23 or less, and even more preferably 0.22 or less. The Poisson's ratio depends on the type of crystals constituting the crystalline phase, Li ２ Si ２ O ５It can be adjusted by the content of crystals and the composition of the crystallized glass. The Poisson's ratio is calculated as the combined value of the crystalline phase dispersed in the crystallized glass and the amorphous phase, if any.

[0070] The reason why crystallized glass with high Poisson's ratio has excellent scratch resistance is not clear, but crystallized glass with high Poisson's ratio is easy to undergo plastic flow when pressure is applied, and it is easy to release the generated stress.On the other hand, crystallized glass with low Poisson's ratio accumulates stress inside crystallized glass when pressure is applied, and the stress remains.In contrast, the crystallized glass according to this embodiment has high Poisson's ratio as described above, so that even when pressure is applied, residual stress is small, and cracks can be reduced, and therefore it is thought that scratch damage can also be prevented.

[0071] In this embodiment, we have newly discovered that scratching tests using a conical diamond indenter with a 90-degree facing indenter angle can adequately reproduce scratches under actual use conditions. The specific measurement conditions are as follows: Conditions: A conical diamond indenter with a 90-degree facing indenter angle is used as the scratching tip. The tip of the conical diamond indenter is pressed against the surface of the crystallized glass, and three scratches with a length of 10 mm are created at a speed of 1 mm / sec while applying a constant load. For each of the three scratches, the widths of the three largest scratch widths are measured for a total of nine scratches, and the average value is taken as the scratch width.

[0072] In addition, since the crystallized glass according to this embodiment is homogeneous and isotropic without anisotropy, the three scratches can be formed in the same direction or in different directions, and are optional. Also, for the same reason, the scratches can be straight or curved, or can be a combination of these shapes, and are optional. However, since the thickness and surface properties of the glass near the edge of the crystallized glass may not be constant, it is preferable that the scratches are formed in an area 5 mm or more inside from the edge of the glass.

[0073] When a scratch test is performed on the crystallized glass of this embodiment under the above conditions with a load of 0.6 N, the scratch width is preferably 60 μm or less, more preferably 50 μm or less, even more preferably 40 μm or less, and even more preferably 35 μm or less, and the smaller the better.

[0074] When a scratch test is performed on the crystallized glass of this embodiment under the above conditions with a load of 0.9 N, the scratch width is preferably 90 μm or less, more preferably 80 μm or less, even more preferably 70 μm or less, and even more preferably 60 μm or less, and the smaller the better.

[0075] The scratch width when a load of 1.2 N is applied to the crystallized glass of this embodiment under the above conditions is preferably 120 μm or less, more preferably 100 μm or less, even more preferably 90 μm or less, and even more preferably 80 μm or less, and the smaller the better. These scratch widths depend on the type of crystals constituting the crystal layer, Li ２ Si ２ O ５ It can be adjusted by the content of crystals, the composition of the crystallized glass, and the Poisson's ratio of the crystallized glass.

[0076] The fracture toughness value K of the crystallized glass according to this embodiment ＩＣ is 1.2 MPa m １／２ or more is preferable, and 1.3 to 2.0 MPa m １／２ Here, from the viewpoint of high strength, the fracture toughness value K ＩＣ is 1.2 MPa m １／２ More preferably, 1.3 MPa m １／２ More preferably, 1.4 MPa m １／２ More preferably, 1.5 MPa m １／２ The above is even more preferable. ＩＣ The upper limit is not particularly limited, but is, for example, 2.0 MPa m １／２ The fracture toughness value K ＩＣ is the type of crystal that constitutes the crystalline phase, Li ２ Si ２ O ５ This can be adjusted by the content of crystals and the composition of the crystallized glass.

[0077] The fracture toughness value K ＩＣ is measured with reference to the DCDC method [Reference: M. Y. He, M. R. Turner and A. G. Evans, Acta Metall. Mater. 43 (1995) 3453.]. Specifically, using a sample having the shape shown in FIG. 1 and a SHIMADZU Autograph AGS-X5KN, the stress intensity factor K1 (unit: MPa m) as shown in FIG. １／２ The K1-v curve, which shows the relationship between the stress intensity factor K1 at 0.1 m / s and the crack propagation velocity v (unit: m / s), was measured, and the obtained Region III data was regressed and extrapolated using a linear equation to determine the fracture toughness value K1. ＩＣ Let's say.

[0078] The surface hardness Hv of the crystallized glass according to this embodiment is preferably 700 to 900 HV. From the viewpoint of scratch resistance and excellent abrasion resistance, the surface hardness Hv is preferably 700 HV or more, more preferably 750 HV or more, and even more preferably 800 HV or more. From the viewpoint of reducing brittleness, the surface hardness Hv is preferably 900 HV or less, more preferably 870 HV or less. The surface hardness Hv depends on the type of crystals constituting the crystalline phase, Li ２ Si ２ O ５ The surface hardness Hv can be adjusted by the content of crystals, the composition of the crystallized glass, and the manufacturing method. Note that the surface hardness Hv in this specification refers to the Vickers hardness (HV100) specified in JIS Z 2244:2009.

[0079] Fracture toughness value K of the crystallized glass according to this embodiment ＩＣ (MPa m １／２ ) to the surface hardness Hv (HV) (surface hardness Hv / fracture toughness value K ＩＣ The brittleness B is 650HV / (MPa m １／２ ) or less, and 500 to 640 HV / (MPa m １／２ From the viewpoint of scratch resistance, the brittleness B is more preferably 650 HV / (MPa m １／２ ) or less, and 640HV / (MPa m １／２ ) or less is more preferable, and 630HV / (MPa m１／２ ) or less is more preferable, and 620HV / (MPa m １／２ ) or less is even more preferable, and 600HV / (MPa m １／２ ) or less, and 580HV / (MPa m １／２ ) or less. The lower limit is not particularly limited, but may be, for example, 500 HV / (MPa m １／２ The brittleness B may be determined by the type of crystals constituting the crystalline phase, Li ２ Si ２ O ５ This can be adjusted by the content of crystals and the composition of the crystallized glass.

[0080] The Young's modulus of the crystallized glass according to this embodiment is preferably 105 GPa or more, and may be 105 to 120 GPa. From the viewpoint of high strength, the Young's modulus is preferably 105 GPa or more, more preferably 107 GPa or more, and even more preferably 109 GPa or more. From the viewpoint of high strength, the higher the Young's modulus, the more preferable it is, but is not particularly limited, and may be, for example, 120 GPa or less. The Young's modulus in this specification can be measured by an ultrasonic method.

[0081] The haze value of the crystallized glass according to this embodiment is preferably 0.03 to 0.30%, and may be 0.05 to 0.25%. From the viewpoint of visibility when the crystallized glass is used as a cover glass, particularly a three-dimensionally shaped cover glass, the haze value is preferably 0.30% or less, more preferably 0.25% or less, even more preferably 0.20% or less, even more preferably 0.18% or less, even more preferably 0.15% or less, and particularly preferably 0.10% or less. The smaller the haze value, the better, but it may usually be 0.03% or more, or even 0.05% or more. The haze value can be adjusted by the crystal species, degree of crystallization, and glass composition. The haze value in this specification refers to the value measured using a C illuminant in accordance with JIS K 7136:2000, converted into a 0.6 mm thickness of the crystallized glass. Furthermore, when the actual thickness of the crystallized glass is not 0.6 mm, the haze value can be converted into a 0.6 mm thickness based on the measured value using the Lambert-Beer law. Furthermore, when the plate thickness t is greater than 0.6 mm, the plate thickness of the crystallized glass may be adjusted to 0.6 mm by polishing, etching, or the like, before measurement.

[0082] The density of the crystallized glass according to this embodiment is 2.40 to 2.60 g / cm ３ Here, from the viewpoint of strength, the density is preferably 2.40 g / cm ３ More than 2.45 g / cm ３ From the viewpoint of increasing the weight of the cover glass, the density is more preferably 2.60 g / cm. ３ Preferably, 2.55 g / cm or less ３ The following is more preferred:

[0083] The average particle size of the crystallized glass according to this embodiment is preferably 50 to 200 nm, and more preferably 80 to 120 nm. From the viewpoint of strength, the average particle size is preferably 50 nm or more, and more preferably 80 nm or more. From the viewpoint of haze, the average particle size is preferably 200 nm or less, and more preferably 120 nm or less. The term "average particle size" as used herein refers to the 50% particle size (D50) on a volume basis in the cumulative particle size distribution. Specifically, the term refers to the particle size at which the cumulative amount accounts for 50% on a volume basis in the cumulative particle size curve of the particle size distribution measured using a laser diffraction / scattering particle size distribution analyzer.

[0084] The thickness of the crystallized glass according to this embodiment is preferably 0.2 to 2.0 mm, and more preferably 0.4 to 1.5 mm. From the viewpoint of obtaining sufficient strength, the thickness is preferably 0.2 mm or more, and more preferably 0.4 mm or more. The upper limit is not particularly limited, but may be, for example, 2.0 mm or less, or 1.5 mm or less.

[0085] <Chemically strengthened glass> The crystallized glass according to this embodiment may be chemically strengthened glass having a compressive stress layer formed by ion exchange on the surface layer. The matrix composition of the chemically strengthened glass is the composition of the crystallized glass before chemical strengthening treatment (ion exchange treatment), and except in cases where extreme ion exchange treatment has been performed, the composition of the chemically strengthened glass deeper than the compressive stress layer depth (DOL) can be considered to be the same as the matrix composition of the chemically strengthened glass. In other words, the composition of the center of the plate thickness of the chemically strengthened glass coincides with the matrix composition of the chemically strengthened glass and can be considered to be the same as the composition of the crystallized glass.

[0086] The chemically strengthened glass according to this embodiment is preferably a chemically strengthened glass in which Li ions in the surface layer of the crystallized glass are ion-exchanged with Na ions. ２ The content of O is determined based on the composition of the glass-ceramics before chemical strengthening, i.e., the Na content in the base composition of the chemically strengthened glass. ２ The content of Na is preferably higher than that of O, and the difference is more preferably 1 mol % or more, further preferably 5 mol % or more, and even more preferably 10 mol % or more. ２The upper limit of the difference in the O content is not particularly limited, but is, for example, 30 mol % or less.

[0087] From the viewpoint of improving the falling ball strength and the drop strength, the chemically strengthened glass according to this embodiment preferably has a compressive stress layer in which Na ions are ion-exchanged with K ions in addition to the ion exchange of Li ions and Na ions. In this case, a surface compressive stress is imparted to a portion close to the surface of the glass due to the ion exchange of Na ions with K ions, and a deep compressive stress is imparted to a portion deeper than that due to the ion exchange of Li ions with Na ions.

[0088] The chemically strengthened glass according to this embodiment does not show any significant changes in the overall composition and crystallinity of the glass, as well as its characteristics and physical properties (other than strength), compared to the crystallized glass before chemical strengthening, and can be considered to be the same. However, the peak position in the X-ray diffraction (XRD) pattern of the surface of the crystallized glass shifts from before the chemical strengthening treatment. In addition, the surface layer of the chemically strengthened glass may have different composition, crystal structure, and crystallinity.

[0089] Regarding the above XRD pattern, in the X-ray diffraction pattern of the surface using Cu-Kα radiation, Li ２ Si ２ O ５ The peak position derived from the crystal may shift before and after ion exchange, or may shift to a lower angle. The peak shift means that the ions in the crystal are also exchanged. The XRD measurement is performed on the surface of the crystallized glass before and after chemical strengthening treatment using CuKα radiation in the 2θ range of 10° to 80°. Specifically, the Li of the chemically strengthened glass ２ Si ２ O ５ Of the peaks derived from the crystals, the peak shift from the peak before ion exchange is preferably 0.02° or more, more preferably 0.02 to 0.10°. Here, the peak shift is preferably 0.02° or more, more preferably 0.03° or more. Furthermore, from the viewpoint of maintaining the crystal structure, the peak shift is preferably 0.10° or less, more preferably 0.08° or less.

[0090] The chemically strengthened glass according to this embodiment may have different physical properties related to strength compared to the crystallized glass before chemical strengthening. Examples of the physical properties include compressive stress (CS), compressive stress layer depth (DOL), internal tensile stress (CT), ST limit, fracture toughness, Young's modulus, Vickers hardness, scratch width, etc. On the other hand, no significant changes are observed in physical properties other than strength, such as haze value, average transmittance, and average thermal expansion coefficient, before and after chemical strengthening.

[0091] The compressive stress value (CS ０ From the viewpoint of preventing cracks due to deformation such as bending, the compressive stress value (CS) at the outermost surface is preferably 300 MPa or more, more preferably 500 MPa or more, and even more preferably 600 MPa or more. ０ The upper limit of the compressive stress value (CS) at the outermost surface is not particularly limited, but is, for example, 1400 MPa or less. ０ ) can be adjusted, for example, by the Na concentration in the molten salt used in the chemical strengthening treatment, the chemical strengthening treatment conditions, the Li concentration in the glass composition, etc.

[0092] The compressive stress value (CS) of the chemically strengthened glass according to this embodiment at a depth of 50 μm ５０ ) is preferably 10 MPa or more, more preferably 30 MPa or more, and even more preferably 50 MPa or more, from the viewpoint of preventing cracks due to deformation such as bending. ５０ The upper limit of the stress is preferably 220 MPa or less, more preferably 200 MPa or less, even more preferably 170 MPa or less, still more preferably 140 MPa or less, and even more preferably 110 MPa or less.

[0093] The compressive stress value (CS) of the chemically strengthened glass according to this embodiment at a depth of 90 μm ９０ From the viewpoint of preventing cracks due to deformation such as bending, CS is preferably 0 MPa or more, more preferably 10 MPa or more, even more preferably 20 MPa or more, and most preferably 30 MPa or more. ９０ The upper limit is not particularly limited, but is, for example, 150 MPa or less.

[0094] The compressive stress value (CS) of the chemically strengthened glass according to this embodiment at a depth of 120 μm １２０ ) is preferably −20 MPa or more, more preferably −10 MPa or more, more preferably 0 MPa or more, and most preferably 10 MPa or more, from the viewpoint of preventing cracks due to deformation such as bending. １２０ The upper limit is not particularly limited, but is, for example, 80 MPa or less.

[0095] In this specification, the compressive stress value (CS) can be measured by slicing a cross section of chemically strengthened glass and analyzing the slicing sample with a birefringence imaging system. An example of a birefringence imaging system is the Abrio-IM birefringence imaging system manufactured by Tokyo Instruments Inc. The compressive stress value can also be measured using scattered light photoelasticity. In this method, light is incident on the surface of the chemically strengthened glass, and the polarization of the scattered light is analyzed to measure CS. An example of a stress measuring instrument using scattered light photoelasticity is the scattered light photoelasticity stress meter SLP-2000 manufactured by Orihara Seisakusho Co., Ltd.

[0096] An optical waveguide surface stress meter is a measuring instrument used to measure the compressive stress on the outermost surface of chemically strengthened glass. Optical waveguide surface stress meters can accurately measure glass stress in a short time. However, in principle, optical waveguide surface stress meters can only measure stress when the refractive index decreases from the sample surface toward the interior. Here, if the outermost layer of chemically strengthened glass is a layer obtained by replacing sodium ions inside the glass with potassium ions from the outside, the refractive index decreases from the sample surface toward the interior, so stress can be measured with an optical waveguide surface stress meter. When measuring compressive stress using an optical waveguide surface stress meter, measurements are performed under the following conditions, for example. - Measuring device: FSM-6000 (manufactured by Orihara Seisakusho Co., Ltd.) - Measurement wavelength: 365 nm

[0097] The compressive stress layer depth (DOL) of the chemically strengthened glass according to this embodiment is preferably 50 μm or more, more preferably 70 μm or more, even more preferably 90 μm or more, and even more preferably 110 μm or more, from the viewpoint of preventing cracking when scratches occur on the surface of the chemically strengthened glass. The upper limit of the compressive stress layer depth is not particularly limited, but is, for example, 200 μm or less. The value of the compressive stress layer depth can be adjusted, for example, by the molten salt, temperature, time, etc. used in the chemical strengthening treatment. In this specification, the compressive stress layer depth (DOL) is the depth at which the compressive stress value (CS) becomes zero.

[0098] The compressive stress layer depth (DOL) of the chemically strengthened glass according to this embodiment is preferably {t × 0.13} μm or more relative to the plate thickness t (μm), and more preferably {t × 0.13 + 10} μm or more and {t × 0.13 + 70} μm or less. Here, from the viewpoint of preventing cracks when scratches occur on the surface of the chemically strengthened glass, the compressive stress layer depth DOL is preferably {t × 0.13} μm or more, more preferably {t × 0.13 + 10} μm or more, even more preferably {t × 0.13 + 20} μm or more, and even more preferably {t × 0.13 + 25} μm or more. Further, from the viewpoint of improving the productivity of the strengthening process, the compressive stress layer depth DOL is preferably {t × 0.13 + 70} μm or less, more preferably {t × 0.13 + 50} μm or less, and even more preferably {t × 0.13 + 40} μm or less.

[0099] <<Uses>> The crystallized glass according to this embodiment is useful as a cover glass for electronic devices such as mobile devices such as mobile phones and smartphones. It is also useful as a cover glass for non-portable electronic devices such as televisions, personal computers, and touch panels, as well as elevator walls and wall surfaces (full-surface displays) of buildings such as houses and buildings. It is also useful as building materials such as window glass, tabletops, interiors of automobiles and airplanes, and their cover glass, as well as for curved housings. Furthermore, the crystallized glass according to this embodiment becomes extremely useful for each of the above applications by undergoing a chemical strengthening treatment.

[0100] <<Method for manufacturing crystallized glass>> The method for manufacturing crystallized glass according to this embodiment is not particularly limited, but includes, for example, the following steps 1 and 2. Furthermore, when crystallized glass is converted into chemically strengthened glass by chemical strengthening treatment, it is preferable to further include the following step 3 in addition to step 1 and step 2.

[0101] Step 1: A step of producing amorphous glass. Step 2: A step of crystallizing the amorphous glass obtained in step 1 to obtain crystallized glass. Step 3: A step of chemically strengthening the crystallized glass obtained in step 2 to obtain chemically strengthened glass.

[0102] Each step will be described below.

[0103] <Step 1> Step 1 is a step of producing amorphous glass, and a conventionally known method can be used as the specific method. That is, when obtaining amorphous glass, for example, glass raw materials are blended to obtain a desired composition and heated and melted in a glass melting furnace. The molten glass is then homogenized by bubbling, stirring, adding a fining agent, etc., formed into a desired shape by a known forming method, and slowly cooled. Alternatively, the molten glass may be formed into a block, slowly cooled, and then cut and processed into a desired shape. Examples of glass forming methods include the float method, the press method, the fusion method, and the downdraw method. Examples of slowly cooling methods include a method of cooling to room temperature at a rate of 0.1 to 2°C / min. The slowly cooling may be performed by holding the glass at a specific temperature for a specific time and then cooling to room temperature. Specifically, for example, the glass may be held at 420 to 550°C for 10 to 180 minutes and then cooled to room temperature at a rate of 0.1 to 2°C / min.

[0104] <Step 2> Step 2 is a step of obtaining crystallized glass by crystallizing the amorphous glass obtained in step 1. This results in crystallized glass having a crystalline phase and a desired composition.

[0105] The heat treatment for crystallization is not particularly limited as long as it produces the desired crystals, but may be, for example, a two-stage heat treatment in which the temperature is raised from room temperature to a first treatment temperature and maintained for a certain period of time, and then maintained at a second treatment temperature higher than the first treatment temperature for a certain period of time. After the two-stage heat treatment, a three-stage heat treatment may be performed in which the temperature is maintained at a third treatment temperature for a certain period of time. Alternatively, a one-stage heat treatment in which the temperature is maintained at a specific treatment temperature and then cooled to room temperature may be performed.

[0106] In the case of a two-stage heat treatment, the first treatment temperature is preferably in a temperature range where the crystal nucleation rate is high for the glass composition, and the second treatment temperature is preferably in a temperature range where the crystal growth rate is high for the glass composition.

[0107] In the case of a three-stage heat treatment, it is preferable that the first and second treatment temperatures are temperatures at which the crystal nucleation rate increases, and the third treatment temperature is a temperature at which the crystal growth rate increases. Alternatively, the first treatment temperature may be a temperature at which the crystal nucleation rate increases, and the second and third treatment temperatures may be temperatures at which the crystal growth rate increases.

[0108] In the two-stage heat treatment and the three-stage heat treatment, the holding time at the first treatment temperature is preferably long enough to generate a sufficient number of crystal nuclei. The generation of a large number of crystal nuclei reduces the size of each crystal, resulting in a highly transparent crystallized glass.

[0109] More specifically, in the case of a two-stage treatment, for example, the first treatment temperature is held at 500°C to 700°C for 1 hour to 6 hours, and then the second treatment temperature is held at 600°C to 800°C for 1 hour to 6 hours.

[0110] More specifically, in the case of a three-stage treatment, for example, after holding at a first treatment temperature of 450°C to 600°C for 1 hour to 6 hours, for example, at a second treatment temperature of 500°C to 650°C for 1 hour to 6 hours, and further, for example, at a third treatment temperature of 600°C to 800°C for 1 hour to 6 hours.

[0111] More specifically, in the case of a one-stage treatment, the temperature may be maintained at 500° C. to 800° C. for 1 hour to 6 hours.

[0112] The crystallized glass obtained in step 2 may be ground and polished as necessary. When the crystallized glass obtained is cut to a predetermined shape and size or chamfered, it is preferable to perform the cutting or chamfering before performing the chemical strengthening treatment in the next step 3. This allows a compressive stress layer to be formed on the cut surface or the chamfered surface by the subsequent chemical strengthening treatment.

[0113] <Step 3> Step 3 is a step of obtaining chemically strengthened glass by performing a chemical strengthening treatment on the crystallized glass obtained in step 2. The chemical strengthening treatment is a treatment in which the glass is brought into contact with a metal salt (e.g., potassium nitrate) containing a metal ion with a large ionic radius (typically, Na ion or K ion) by, for example, immersing the glass in a melt of the metal salt, thereby replacing the metal ion with a small ionic radius (typically, Li ion or Na ion) with a metal ion with a large ionic radius (typically, Na ion or K ion for Li ion, and K ion for Na ion).

[0114] To increase the speed of chemical strengthening, it is preferable to use "Li-Na exchange," which exchanges Li ions in the glass with Na ions. Here, the crystallized glass in this embodiment contains a crystalline phase, but a compressive stress layer is formed not only in the amorphous phase but also when Li constituting the crystalline phase is converted to Na.

[0115] In order to form a larger compressive stress by ion exchange, it is preferable to use "Na-K exchange" in which Na ions in the glass are exchanged with K ions.

[0116] Examples of molten salts for chemical strengthening include nitrates, sulfates, carbonates, and chlorides. Examples of nitrates include lithium nitrate, sodium nitrate, potassium nitrate, cesium nitrate, and silver nitrate. Examples of sulfates include lithium sulfate, sodium sulfate, potassium sulfate, cesium sulfate, and silver sulfate. Examples of carbonates include lithium carbonate, sodium carbonate, and potassium carbonate. Examples of chlorides include lithium chloride, sodium chloride, potassium chloride, cesium chloride, and silver chloride. These molten salts may be used alone or in combination.

[0117] When both Li—Na exchange and Na—K exchange are performed, for example, a mixed molten salt of lithium nitrate, sodium nitrate, and potassium nitrate may be used. In this case, the mixing ratio of lithium nitrate, sodium nitrate, and potassium nitrate is not particularly limited, but for example, when lithium nitrate, sodium nitrate, and potassium nitrate are used, the lithium nitrate is preferably 0.002 to 0.5 parts by mass, the sodium nitrate is preferably 20 to 90 parts by mass, and the potassium nitrate is preferably 10 to 80 parts by mass.

[0118] The conditions for the chemical strengthening treatment, such as time and temperature, can be selected taking into consideration the glass composition, the type of molten salt, etc. For example, the crystallized glass obtained in step 2 can be chemically strengthened at preferably 500°C or less for preferably 20 hours or less. Alternatively, two or more stages of chemical strengthening treatment may be performed.

[0119] When performing the chemical strengthening treatment in two or more stages, Li—Na exchange may be performed using a molten salt containing sodium, and then Na—K exchange may be performed using a molten salt containing potassium.

[0120] Examples of molten salts for chemical strengthening include nitrates, sulfates, carbonates, and chlorides. Examples of nitrates include lithium nitrate, sodium nitrate, potassium nitrate, cesium nitrate, and silver nitrate. Examples of sulfates include lithium sulfate, sodium sulfate, potassium sulfate, cesium sulfate, and silver sulfate. Examples of carbonates include lithium carbonate, sodium carbonate, and potassium carbonate. Examples of chlorides include lithium chloride, sodium chloride, potassium chloride, cesium chloride, and silver chloride. These molten salts may be used alone or in combination.

[0121] When Li—Na exchange and Na—K exchange are carried out in two stages, a mixed molten salt of lithium nitrate, sodium nitrate, and potassium nitrate may be used. In this case, the mixing ratio of lithium nitrate, sodium nitrate, and potassium nitrate is not particularly limited. For example, when lithium nitrate, sodium nitrate, and potassium nitrate are used, the lithium nitrate is preferably 0.002 to 0.5 parts by mass, the sodium nitrate is preferably 0.05 to 20 parts by mass, and the potassium nitrate is preferably 80 to 99.95 parts by mass.

[0122] The present invention will be described below with reference to test examples, but the present invention is not limited thereto. Examples 1 to 4 are working examples, and Example 5 is a comparative example.

[0123] Example 1 Glass raw materials were mixed according to the oxide-based mol% notation shown in Glass 1 in Table 1 and weighed to obtain 800 g of glass. The mixed glass raw materials were then placed in a platinum crucible and placed in an electric furnace at 1550°C, melted for about 5 hours, degassed, and homogenized. The resulting molten glass was poured into a mold, held at 470°C for 1 hour, and then cooled to room temperature at a rate of 0.5°C / min to obtain a glass block. Note that blanks in the glass composition of Glass 1 in Table 1 indicate that no additives were added.

[0124] The obtained glass block was processed into a plate of 50 mm × 50 mm × 0.6 mm, and subjected to a crystallization treatment by heating under the conditions of holding at 510 ° C for 4 hours, holding at 530 ° C for 2 hours, and holding at 740 ° C for 2 hours, followed by cooling to room temperature to obtain crystallized glass.

[0125] The obtained crystallized glass was subjected to chemical strengthening treatment. Specifically, the glass was immersed in a molten salt mixture (sodium nitrate:potassium nitrate:lithium nitrate = 60:39.97:0.03 (mass ratio)) at 450°C for 4 hours as a first treatment, and then in a molten salt mixture (potassium nitrate:sodium nitrate = 99:1 (mass ratio)) at 450°C for 0.5 hours as a second treatment, followed by washing and drying to obtain chemically strengthened crystallized glass.

[0126] Example 2 Chemically strengthened crystallized glass was obtained by the same procedure as in Example 1, except that only the first stage of chemical strengthening treatment was performed and the second stage of treatment was not performed.

[0127] Example 3: Crystallized glass having the same glass composition as Example 1, Glass 1, was immersed in a molten salt of sodium nitrate at 450°C for 4 hours as a first-stage treatment, and then in a mixed molten salt (potassium nitrate:sodium nitrate=99:1 (mass ratio)) at 450°C for 4 hours as a second-stage treatment, and then washed and dried to obtain chemically strengthened crystallized glass.

[0128] Example 4 As Example 4, commercially available chemically strengthened crystallized glass was prepared, having the composition shown in Glass 2 in Table 1. Since the conditions of the chemical strengthening treatment were unknown, the "chemical strengthening conditions" in Table 2 are marked with "-".

[0129] Example 5 As Example 5, commercially available chemically strengthened crystallized glass was prepared, having the composition shown in Glass 3 in Table 1. Note that since the conditions of the chemical strengthening treatment are unknown, the "chemical strengthening conditions" in Table 2 are marked with "-".

[0130] <Evaluation> <Composition> Composition analysis of the crystallized glasses obtained in Examples 1 to 3 confirmed that there was no significant change from the glass composition before crystallization and that the glass composition was the same as the glass composition listed in Glass 1 in Table 1. Furthermore, there was no significant change in the glass composition before and after chemical strengthening treatment, except for the surface layer. Furthermore, composition analysis of the crystallized glasses in Examples 4 and 5 confirmed that they had the glass compositions listed in Glass 2 and Glass 3 in Table 1, respectively. Note that blank spaces in the glass compositions of Glass 2 and Glass 3 in Table 1 indicate that the corresponding component was not included.

[0131] <Crystalline Phase> Powder X-ray diffraction was measured under the following conditions for the crystallized glasses obtained in Examples 1 to 3 before chemical strengthening treatment, and the chemically strengthened crystallized glasses in Examples 4 and 5, and the precipitated crystals, their content ratios, and the average crystallite size of the crystals were determined by Rietveld analysis. The results are shown in Table 2 as "Crystalline Phase", "Li ２ Si ２ O ５ The "crystallization (mass%)" and "average crystallite size (nm)" are shown. In the table, "-" means that the data was not measured. Measuring device: SmartLab manufactured by Rigaku Corporation X-ray used: Cu-Kα ray Measuring range: 2θ = 10° to 80° Speed: 10° / min Step: 0.02°

[0132] <Average particle size> The average particle size of the glass-ceramics obtained in Examples 1 to 3 before chemical strengthening treatment and the chemically strengthened glass-ceramics in Examples 4 and 5 was calculated as the particle size at which the cumulative amount accounted for 50% by volume in the cumulative particle size curve of the particle size distribution measured using an SEM (scanning electron microscope). The results are shown in "Average particle size (nm)" in Table 2. In the table, "-" means that the measurement was not performed.

[0133] <Haze Value> The haze values ​​(converted to a thickness of 0.6 mm) of the glass-ceramics before chemical strengthening treatment obtained in Examples 1 to 3 and the chemically strengthened glass-ceramics in Examples 4 and 5 were measured using a haze meter (HZ-V3 manufactured by Suga Test Instruments Co., Ltd.) under Illuminant C in accordance with JIS K 7136:2000. The results are shown in "Haze Value (%)" in Table 2.

[0134] <Young's modulus and Poisson's ratio> The Young's modulus and Poisson's ratio of the glass-ceramics before chemical strengthening treatment obtained in Examples 1 to 3 and the chemically strengthened glass-ceramics in Examples 4 and 5 were measured by an ultrasonic method using an ultrasonic thickness gauge (manufactured by Olympus Corporation, product name 38DL). The results are shown in Table 2 under "Young's modulus (GPa)" and "Poisson's ratio."

[0135] <Surface hardness Hv> The surface hardness Hv of the glass-ceramics obtained in Examples 1 to 3 before chemical strengthening treatment and the chemically strengthened glass-ceramics in Examples 4 and 5 was measured using a micro-Vickers hardness tester FT076 according to the method specified in JIS Z 2244: 2009. The results are shown in Table 2 under "Surface hardness Hv (HV)."

[0136] Fracture toughness value K ＩＣ Fracture toughness values ​​K of the crystallized glasses obtained in Examples 1 to 3 before chemical strengthening treatment, and those of Examples 4 and 5 before chemical strengthening treatment ＩＣ was determined by the above-mentioned method using a strength tester (Shimadzu Corporation, Autograph AGS-X). Since the glasses of Examples 4 and 5 are commercially available as chemically strengthened crystallized glasses, crystallized glasses having similar glass compositions and crystalline phase states were prepared and used as simulated glasses of the crystallized glasses before chemical strengthening treatment for measurements. The state of the crystalline phase means that the types of crystals constituting the crystalline phase, their content ratios, the average particle size of the crystalline phase, and the average crystallite size are all similar. The results are shown in Table 2 under "K ＩＣ (MPa m １／２ )" in Table 2. ＩＣ )(HV / (MPa・m １／２ ))) is (surface hardness Hv / fracture toughness value K ＩＣ The value of brittleness B, expressed as follows:

[0137] <Compressive stress depth DOL and compressive stress value CS> For the chemically strengthened crystallized glasses obtained in Examples 1 to 3, and the chemically strengthened crystallized glasses of Examples 4 and 5, the stress profile in the depth direction was measured using a measuring instrument SLP-2000 manufactured by Orihara Seisakusho Co., Ltd. Based on the stress profile, the compressive stress layer depth DOL (μm) was determined. In addition, the compressive stress value CS of the outermost surface of the glass ０ (MPa), compressive stress value CS at a depth of 50 μm ５０ (MPa), compressive stress value CS at a depth of 90 μm ９０ (MPa) and compressive stress value CS at a depth of 120 μm １２０ The results are shown in Table 2 as "DOL (μm)" and "CS ０ (MPa)”, “CS ５０ (MPa)”, “CS ９０ (MPa)" and "CS １２０ (MPa)". In the table, "-" means that the measurement was not performed.

[0138] <Scratch Width> The scratch width of the chemically strengthened crystallized glasses obtained in Examples 1 to 3 and the chemically strengthened crystallized glasses of Examples 4 and 5 was measured using a scratch tester (Micro Combi Tester MCT manufactured by Anton Paar GmbH). ３ ) and a conical diamond indenter (Tokyo Diamond Tool Manufacturing Co., Ltd., cone 90° R 10 μm) as a scratching terminal. The tip of the conical diamond indenter was pressed against the surface of the obtained crystallized glass, and three scratches with a scratch length of 10 mm were formed at a speed of 1 mm / sec while applying a constant load. For each of the three scratches, a total of nine scratch widths were measured for the top three largest scratch widths, and the average value was taken as the scratch width. The scratch width was measured when the load was 0.6 N, 0.9 N, and 1.2 N. The results are shown in Table 2 under "Scratch Width (μm)."

[0139]

[0140]

[0141] From the above results, it can be seen that the crystallized glass according to this embodiment satisfies a specific composition range, thereby ２ Si ２ O ５ The crystals were selectively precipitated to a content of 40 mass % or more, and the glass had a Poisson's ratio of 0.20 or more, resulting in high strength and excellent scratch resistance.

[0142] 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 thereto without departing from the spirit and scope of the present invention. This application is a Japanese patent application filed on April 16, 2025 (Patent Application No. 2025-067535), a Japanese patent application filed on June 7, 2024 (Patent Application No. 2024-092882), a Japanese patent application filed on January 14, 2025 (Patent Application No. 2025-004714), a Japanese patent application filed on February 17, 2025 (Patent Application No. 2025-023653), and a Japanese patent application filed on March 31, 2025. This patent application (Patent Application No. 2025-058528), a Japanese patent application filed on March 31, 2025 (Patent Application No. 2025-058530), a Japanese patent application filed on March 31, 2025 (Patent Application No. 2025-058529), and a Japanese patent application filed on March 31, 2025 (Patent Application No. 2025-058531), the contents of which are incorporated by reference into this application.

Claims

1. A crystallized glass having a crystalline phase, wherein the composition of the crystallized glass is expressed in mole percentage based on oxides: SiO ２ 55-72%, Al ２ O ３ 1.3-4.5%, Li ２ O 15-28%, P ２ O ５ 0.5 to 5.0%, and ZrO ２ 0.5 to 4.4%, and SiO ２ , Al ２ O ３ , and Li ２ Using the content ratio of O expressed as mole percentage, {[SiO ２ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O])} × 100 is 68.5 to 76.0%, ２ O ３ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O])} × 100 is 2.20 to 4.40%, and ２ O] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O])) × 100 is 23.0 to 28.5%, and the crystalline phase satisfies ２ Si ２ O ５ The Li in the glass-ceramics is ２ Si ２ O ５ A crystallized glass having a crystal content of 40 mass % or more and a Poisson's ratio of 0.20 or more.

2. The composition of the crystallized glass is expressed in mole percentage based on oxides: Na ２ O 0.1 to 5%, and K ２ 2. The crystallized glass according to claim 1, further comprising: O 0 to 3%.

3. The Li in the crystallized glass ２ Si ２ O ５ 3. The crystallized glass according to claim 1, wherein the content of crystals other than crystals is 10% by mass or less.

4. The crystallized glass according to claim 1 or 2, wherein the crystallized glass has an amorphous phase, and the content of the amorphous phase in the crystallized glass is 20 mass % or more.

5. The fracture toughness value K of the crystallized glass ＩＣ (MPa m １／２ ) to the surface hardness Hv (HV) (surface hardness Hv / fracture toughness value K ＩＣ ) is 650 (HV / (MPa m １／２ 3. The crystallized glass according to claim 1, wherein the crystallization temperature is 1000°C or less.

6. Fracture toughness value K ＩＣ is 1.2 MPa m １／２ The crystallized glass according to claim 1 or 2, wherein 7. The crystallized glass according to claim 1 or 2, wherein a scratch width is 60 μm or less when the crystallized glass is subjected to a scratch test under the following conditions with a load of 0.6 N: Conditions: A conical diamond indenter with a 90° facing angle was used as a scratching tip. The tip of the conical diamond indenter was pressed against the surface of the crystallized glass, and three scratches, each 10 mm long, were formed at a speed of 1 mm / sec while applying a constant load. For each of the three scratches, the widths of the three largest scratches are measured, for a total of nine scratches, and the average value is taken as the scratch width.

8. The crystallized glass according to claim 1 or 2, wherein a scratch width is 90 μm or less when the crystallized glass is subjected to a scratch test under the following conditions with a load of 0.9 N: Conditions: A conical diamond indenter with a 90° facing angle was used as a scratching tip. The tip of the conical diamond indenter was pressed against the surface of the crystallized glass, and three scratches, each 10 mm long, were formed at a speed of 1 mm / sec while applying a constant load. For each of the three scratches, the widths of the three largest scratches are measured, for a total of nine scratches, and the average value is taken as the scratch width.

9. The crystallized glass according to claim 1 or 2, wherein a scratch width is 120 μm or less when the crystallized glass is subjected to a scratch test under the following conditions with a load of 1.2 N: Conditions: A conical diamond indenter with a 90° facing angle was used as a scratching tip. The tip of the conical diamond indenter was pressed against the surface of the crystallized glass, and three scratches, each 10 mm long, were formed at a speed of 1 mm / sec while applying a constant load. For each of the three scratches, the widths of the three largest scratches are measured, for a total of nine scratches, and the average value is taken as the scratch width.

10. The crystallized glass according to claim 1 or 2, having a Young's modulus of 105 GPa or more.

11. The crystallized glass according to claim 1 or 2, which has a haze value of 0.03 to 0.30% when converted into a glass having a thickness of 0.6 mm.

12. The crystallized glass according to claim 1 or 2, wherein the crystals constituting the crystalline phase have an average crystallite size of 20 to 200 nm.

13. The crystallized glass according to claim 1 or 2, which has a compressive stress layer formed on its surface by ion exchange.

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