Inorganic composition items

Abstract

The objective of the present invention is to obtain an inorganic composition article which is highly transparent and hard. The inorganic composition article contains, as a main crystal phase, at least one selected from an α-cristobalite and an α-cristobalite solid solution, has a coloration degree λ80 of 330-580 nm at a thickness of 10 mm, and has a Vickers hardness of at least 620.

Description

[Technical Field]

[0001] The present invention relates to inorganic composition articles.

[0002] Various inorganic materials are expected to be used as cover glass and housings to protect displays in mobile electronic devices such as smartphones and tablet PCs, as protectors to protect lenses in automotive optical devices, interior bezels and console panels, touch panel materials, smart keys, etc. These devices are required to be used in harsh environments, and there is an increasing demand for inorganic materials with higher hardness. Furthermore, depending on the application, high transparency or low coloring degree is required.

[0003] Glass-ceramics are a type of glass that has increased strength. Glass-ceramics are glass in which crystals are precipitated inside, and are known to have superior mechanical strength to amorphous glass. Furthermore, chemical strengthening is known as a method for increasing the strength of glass-ceramics.

[0004] Patent Document 1 discloses the material composition of an inorganic composition substrate for information recording media. It states that the α-cristobalite-based inorganic composition article described in Patent Document 1 can be chemically strengthened and can be used as a high-strength material substrate. However, crystallized glass for information recording media, such as hard disk substrates, is not intended for use in harsh environments, and transparency is not required. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2008-254984 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide an inorganic composition article that is highly transparent and hard.

[0007] The present invention provides the following: (Configuration 1) An inorganic composition article containing, as a main crystalline phase, one or more selected from α-cristobalite and α-cristobalite solid solution, having a coloring degree λ80 of 330 to 580 nm at a thickness of 10 mm and a Vickers hardness of 620 or more. (Configuration 2) In terms of oxide, mass % SiO2 content is 50.0% to 75.0%. The content of Li2O component is 3.0% to 10.0%. The content of Al2O3 component is 5.0% or more and less than 15.0%. B2O3 content is 0% to 10.0%. ZrO2 content is over 0% and 10.0% or less 2. The inorganic composition article according to claim 1, wherein (Configuration 3) 3. The inorganic composition article according to claim 1 or 2, wherein the total content of the Al2O3 component and the ZrO2 component is 9.5% or more by mass in terms of oxides. (Configuration 4) In terms of oxide, mass % The content of K2O component is 0% to 5.0%. P2O5 content: 0% to 10.0% 4. The inorganic composition article according to any one of configurations 1 to 3, wherein (Configuration 5) In terms of oxide, mass % Na2O content is 0% to 4.0%. MgO content: 0% to 4.0% CaO content is 0% to 4.0%. SrO content is 0% to 4.0%. BaO content is 0% to 5.0%. ZnO content: 0% to 10.0% Sb2O3 content: 0% to 3.0% 5. The inorganic composition article according to any one of configurations 1 to 4, wherein (Configuration 6) In terms of oxide, mass % Nb2O5 content is 0% to 5.0%. Ta2O5 content is 0% to 6.0%. TiO2 content is 0% or more and less than 1.0% 6. The inorganic composition article according to any one of configurations 1 to 5, wherein (Configuration 7) 7. The inorganic composition article according to any one of claims 1 to 6, having a Vickers hardness of 640 or more. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an inorganic composition article that is highly transparent and hard.

[0009] The inorganic composition article of the present invention can be used as a protective material for devices, taking advantage of its high hardness and transparency. It can be used as a cover glass or housing for smartphones, a component for portable electronic devices such as tablet PCs and wearable devices, or a component for protective protectors or head-up display substrates used in transportation vehicles such as cars and airplanes. It can also be used for other electronic devices and machinery, building materials, solar panel components, projector components, and cover glass (windshields) for eyeglasses and watches. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments and examples of the inorganic composition article of the present invention will be described in detail, but the present invention is not limited to the following embodiments and examples in any way, and can be practiced with appropriate modifications within the scope of the object of the present invention.

[0011] The "inorganic composition article" of the present invention is composed of an inorganic composition material such as glass, crystallized glass, ceramics, or a composite material thereof. The article of the present invention includes, for example, an article obtained by molding these inorganic materials into a desired shape by processing or synthesis through chemical reaction. It also includes a green compact obtained by crushing an inorganic material and then pressing it, or a sintered compact obtained by sintering the green compact. The shape of the article obtained here is not limited by smoothness, curvature, size, or the like. For example, it may be a plate-shaped substrate, a molded body with curvature, or a three-dimensional structure with a complex shape.

[0012] The inorganic composition article of the present invention contains at least one crystalline phase selected from α-cristobalite and α-cristobalite solid solution as a main crystalline phase, which increases the mechanical strength. Here, the term "main crystalline phase" in this specification corresponds to the crystalline phase that is most abundant in the glass-ceramics as determined from the peaks in the X-ray diffraction pattern.

[0013] The inorganic composition article of the present invention has a coloring degree λ80 of 330 to 580 nm at a thickness of 10 mm, more preferably 330 to 550 nm, more preferably 330 to 530 nm, and even more preferably 330 to 500 nm. The smaller the wavelength of the coloring degree λ80, the lower the coloring degree and the higher the transparency.

[0014] The inorganic composition article of the present invention has a coloring degree λ5 of 370 nm or less at a thickness of 10 mm, more preferably 360 nm or less, and even more preferably 350 nm or less. The smaller the wavelength of the coloring degree λ5, the lower the coloring degree and the higher the transparency.

[0015] The inorganic composition article of the present invention has a Vickers hardness of 620 or more, more preferably 630 or more, and even more preferably 640 or more.

[0016] A suitable composition range for constituting an inorganic composition article is described below. In this specification, the content of each component is expressed in mass% converted to oxide unless otherwise specified. Here, "oxide converted" refers to the amount of oxide of each component contained in the crystallized glass, expressed in mass%, when the total mass of the oxides is 100 mass%, assuming that all the components constituting the crystallized glass are decomposed and converted to oxides. In this specification, A% to B% means A% or more and B% or less.

[0017] The inorganic composition article of the present invention preferably comprises: In terms of oxide, mass % SiO2 content is 50.0% to 75.0%. The content of Li2O component is 3.0% to 10.0%. The content of Al2O3 component is 5.0% or more and less than 15.0%. B2O3 content is 0% to 10.0%. The content of ZrO2 component is more than 0% and 10.0% or less, This composition facilitates the formation of one or more crystalline phases selected from α-cristobalite and α-cristobalite solid solution.

[0018] The SiO2 component is an essential component required to form one or more selected from α-cristobalite and α-cristobalite solid solutions. If the SiO2 content exceeds 75.0%, excessive viscosity increases and melting properties deteriorate. If the SiO2 content is less than 50.0%, devitrification resistance may deteriorate. Preferably, the upper limit is 75.0% or less, 74.0% or less, 73.0% or less, 72.0% or less, or 70.0% or less, and preferably the lower limit is 50.0% or more, 55.0% or more, 58.0% or more, or 60.0% or more.

[0019] The Li2O component is a component that improves the meltability of the base glass, but if its content is less than 3.0%, the above effect cannot be obtained and the base glass becomes difficult to melt, while if its content exceeds 10.0%, the formation of lithium disilicate crystals increases. The Li2O component also contributes to chemical strengthening. Preferably, the lower limit is 3.0% or more, 3.5% or more, 4.0% or more, 4.5% or more, 5.0% or more, or 5.5% or more, and preferably the upper limit is 10.0% or less, 9.0% or less, 8.5% or less, or 8.0% or less.

[0020] The Al2O3 component is a component suitable for improving the mechanical strength of inorganic composition articles. If the Al2O3 content is 15.0% or more, the melting property and devitrification resistance may deteriorate, and if it is less than 5.0%, the effect of improving the mechanical strength may be poor. Preferably, the upper limit is less than 15.0%, 14.5% or less, 14.0% or less, 13.5% or less, or 13.0% or less, and preferably the lower limit is 5.0% or more, 5.5% or more, 5.8% or more, 6.0% or more, or 6.5% or more.

[0021] The B2O3 component is a suitable component for lowering the glass transition temperature of the inorganic composition article, but if the amount exceeds 10.0%, the chemical durability may be easily reduced. Preferably, the upper limit is 10.0% or less, 8.0% or less, 7.0% or less, 5.0% or less, or 4.0% or less, and the lower limit can be 0%, 0.001% or more, 0.01% or more, 0.05% or more, 0.10% or more, or 0.30% or more.

[0022] The ZrO2 component is a component that can improve the mechanical strength, but if the amount exceeds 10.0%, there is a risk that the meltability will deteriorate. The upper limit is preferably 10.0% or less, 9.0% or less, 8.5% or less, or 8.0% or less, and the lower limit can be more than 0%, 1.0% or more, 1.5% or more, or 2.0% or more.

[0023] If the sum of the contents of the Al2O3 component and the ZrO2 component, [Al2O3 + ZrO2], is high, the compressive stress on the surface increases when strengthened. Preferably, the lower limit of [Al2O3 + ZrO2] is set to 9.5% or more, 10.0% or more, 11.0% or more, 12.0% or more, or 13.0% or more. On the other hand, if it is contained in excess, the meltability may be deteriorated. Therefore, the upper limit of [Al2O3 + ZrO2] is preferably set to 22.0% or less, 21.0% or less, 20.0% or less, or 19.0% or less.

[0024] The lower limit of the total content of the SiO2 component, Li2O component, Al2O3 component, B2O3 component, and ZrO2 component can be preferably set to 75.0% or more, 80.0% or more, 83.0% or more, or 85.0% or more.

[0025] The P2O5 component is an optional component that can be added to act as a crystal nucleating agent for glass, but if the amount exceeds 10.0%, there is a risk that devitrification resistance will deteriorate and glass phase separation will be more likely to occur. Preferably, the upper limit is 10.0% or less, 8.0% or less, 6.0% or less, 5.0% or less, or 4.0% or less, and preferably, the lower limit can be 0% or more, 0.5% or more, 1.0% or more, or 1.5% or more.

[0026] The K2O component is an optional component that contributes to chemical strengthening, and the lower limit can be preferably set to 0% or more, 0.1% or more, 0.3% or more, or 0.5% or more. Moreover, if it is contained in excess, crystal precipitation may become difficult in some cases. Therefore, the upper limit can be preferably set to 5.0% or less, 4.0% or less, 3.5% or less, or 3.0% or less.

[0027] The Na2O component is an optional component involved in chemical strengthening. If it is contained in excess, it may be difficult to obtain the desired crystal phase. The upper limit can be set to preferably 4.0% or less, 3.5% or less, more preferably 3.0% or less, and even more preferably 2.5% or less.

[0028] The MgO, CaO, SrO, BaO, and ZnO components are optional components that improve low-temperature melting properties and can be included within a range that does not impair the effects of the present invention. Therefore, the upper limit of the MgO component can be preferably set to 4.0% or less, 3.5% or less, 3.0% or less, or 2.7% or less. The lower limit of the MgO component can be preferably set to 0% or more, more than 0%, 0.3% or more, or 0.4% or more. The upper limit of the CaO component can be preferably set to 4.0% or less, 3.0% or less, 2.5% or less, or 2.0% or less. The upper limit of the SrO component can be preferably set to 4.0% or less, 3.0% or less, 2.5% or less, or 2.0% or less. The upper limit of the BaO component can be preferably set to 5.0% or less, 4.0% or less, 3.0% or less, 2.5% or less, or 2.0% or less. The upper limit of the ZnO component can be preferably set to 10.0% or less, 9.0% or less, 8.5% or less, 8.0% or less, or 7.5% or less, and the lower limit of the ZnO component can be preferably set to 0% or more, more than 0%, 0.5% or more, or 1.0% or more.

[0029] The inorganic composition article may or may not contain Nb2O5, Ta2O5, and TiO2 components, as long as the effects of the present invention are not impaired. Nb2O5 is an optional component that improves the mechanical strength of crystallized glass when contained in an amount greater than 0%. The upper limit can be preferably 5.0%, 4.0%, 3.5%, or 3.0%. Ta2O5 is an optional component that improves the mechanical strength of crystallized glass when contained in an amount greater than 0%. The upper limit can be preferably 6.0%, 5.5%, 5.0%, or 4.0%. TiO2 is an optional component that improves the chemical durability of crystallized glass when contained in an amount greater than 0%. The upper limit can be preferably less than 1.0%, 0.8%, 0.5%, or 0.1%.

[0030] The inorganic composition article may or may not contain La2O3, Y2O3, Gd2O3, WO3, TeO2, and Bi2O3 components within the range that does not impair the effects of the present invention. The blending amount of each component can be 0% to 2.0%, 0% to less than 2.0%, or 0% to 1.0%.

[0031] Furthermore, the inorganic composition article may or may not contain other components not described above, provided that the properties of the inorganic composition article of the present invention are not impaired. For example, metal components such as Yb, Lu, V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo (including oxides of these metals) may be contained.

[0032] Sb2O3 may be added as a fining agent for glass. However, excessive Sb2O3 content may result in poor transmittance in the short wavelength region of the visible light spectrum. Therefore, the upper limit of Sb2O3 content is preferably set to 3.0%, more preferably 1.0%, and even more preferably 0.6%.

[0033] Furthermore, as a fining agent for glass, in addition to the Sb2O3 component, the glass may or may not contain one or more elements selected from the group consisting of SnO2, CeO2, As2O3, and F, NOx, and SOx. However, the upper limit of the content of the fining agent can be set to preferably 3.0% or less, more preferably 1.0% or less, and most preferably 0.6% or less.

[0034] On the other hand, since there has been a recent trend to refrain from using Pb, Th, Tl, Os, Be, Cl and Se as harmful chemical substances, it is preferable that these components are substantially not contained.

[0035] The inorganic composition article can be produced by the following method: raw materials are uniformly mixed so that each component falls within a predetermined content range, and then melt-molded to produce a raw material article, which is then crystallized to produce the inorganic composition article of the present invention.

[0036] The heat treatment for crystallization may be carried out in one stage or at two temperatures. In the two-stage heat treatment, a nucleation step is first performed by heat treatment at a first temperature, and after this nucleation step, a crystal growth step is performed by heat treatment at a second temperature higher than that of the nucleation step. The first temperature of the two-stage heat treatment is preferably 450° C. to 750° C., more preferably 500° C. to 720° C., and even more preferably 550° C. to 680° C. The holding time at the first temperature is preferably 30 minutes to 2000 minutes, and more preferably 180 minutes to 1440 minutes. The second temperature of the two-stage heat treatment is preferably 550° C. to 850° C., more preferably 600° C. to 800° C. The holding time at the second temperature is preferably 30 minutes to 600 minutes, more preferably 60 minutes to 400 minutes.

[0037] In one-stage heat treatment, the nucleation process and the crystal growth process are carried out consecutively at a single temperature. Typically, the temperature is raised to a predetermined heat treatment temperature, and after reaching that temperature, the temperature is maintained for a certain period of time, and then the temperature is lowered. When heat treatment is performed at one temperature step, the heat treatment temperature is preferably 600 to 800° C., more preferably 630 to 770° C. The holding time at the heat treatment temperature is preferably 30 to 500 minutes, more preferably 60 to 400 minutes.

[0038] The obtained inorganic composition article can be strengthened to form a compressive stress layer on the surface. Strengthening methods include, for example, a chemical strengthening method in which an alkali component present in the surface layer of the inorganic composition article is subjected to an exchange reaction with an alkali component having a larger ionic radius to form a compressive stress layer in the surface layer. Other methods include a thermal strengthening method in which the inorganic composition article is heated and then rapidly cooled, and an ion implantation method in which ions are implanted into the surface layer of the inorganic composition article.

[0039] The chemical strengthening method can be carried out, for example, by the following steps: The inorganic composition article is brought into contact with or immersed in a molten salt of a salt containing potassium or sodium, such as potassium nitrate (KNO), sodium nitrate (NaNO), or a mixed or composite salt thereof. This treatment of contacting or immersing in the molten salt (chemical strengthening treatment) may be carried out in one step or two steps.

[0040] The thermal strengthening method is not particularly limited, but for example, an inorganic composition article may be heated to 300°C to 600°C, and then rapidly cooled by water cooling and / or air cooling, thereby forming a compressive stress layer due to the temperature difference between the surface and the interior of the glass. Note that by combining this with the above-mentioned chemical treatment method, the compressive stress layer can be formed more effectively.

[0041] The ion implantation method is not particularly limited, but for example, ions are implanted into the surface of an inorganic composition article by bombarding the surface with an acceleration energy and acceleration voltage that are not enough to destroy the surface. Then, by performing a heat treatment as necessary, a compressive stress layer can be formed on the surface in the same manner as other methods. [Example]

[0042] Examples 1 to 38, Comparative Example 1 As raw materials for each component of the crystallized glass, raw materials such as oxides, hydroxides, carbonates, nitrates, fluorides, chlorides, metaphosphate compounds, etc. were selected, and these raw materials were weighed and uniformly mixed to obtain the compositions shown in Tables 1 to 4.

[0043] Next, the mixed raw materials were placed in a platinum crucible and melted in an electric furnace at 1300°C to 1600°C for 2 to 24 hours, depending on the melting difficulty of the glass composition. The molten glass was then stirred to homogenize it, and the temperature was lowered to 1000°C to 1450°C before being poured into a mold and slowly cooled to produce base glass. The obtained base glass was heated under the crystallization conditions shown in Tables 1 to 4 to produce crystallized glass.

[0044] The crystalline phases of the glass-ceramics of Examples 1 to 38 and Comparative Example 1 were determined from the angles of peaks appearing in X-ray diffraction patterns obtained using an X-ray diffraction analyzer (D8Discover, manufactured by Bruker). Since the glass-ceramics of Examples 1 to 38 all had a main peak (the peak with the highest intensity and largest peak area) at a position corresponding to the peak pattern of α-cristobalite and / or α-cristobalite solid solution, it was determined that α-cristobalite and / or α-cristobalite solid solution had precipitated as the main crystalline phase. The glass-ceramics of Comparative Example 1 did not show peaks corresponding to α-cristobalite or α-cristobalite solid solution. In Comparative Example 1, crystalline phases of MgAl2O4 and MgTi2O4 were confirmed.

[0045] The produced crystallized glass was cut and ground, and then polished parallel to each other to a thickness of 10 mm to obtain a crystallized glass substrate.

[0046] The crystallized glass was evaluated as follows, and the results are shown in Tables 1 to 4. (1) Vickers hardness Vickers hardness is measured by applying a pyramidal indenter with a 136° angle to the test surface, and measuring the load applied to the indentation relative to the surface area (mm ) calculated from the indentation length. 2 The hardness was measured using a Shimadzu Corporation micro Vickers hardness tester HMV-G21D with a test load of 100 gf and a holding time of 10 seconds.

[0047] (2) Coloring degree The light transmittance, including reflection loss, at a thickness of 10 mm was measured using a spectrophotometer (Hitachi High-Technologies, U-4000 model). The wavelength at which the transmittance was 5% (λ5) and the wavelength at which the transmittance was 80% (λ80) were determined.

[0048] [Table 1]

[0049] [Table 2]

[0050] Table 3

[0051] Table 4

Claims

1. The main crystalline phase contains one or more selected from α-cristobalite and α-cristobalite solid solution, the coloring degree λ80 at a thickness of 10 mm is 330 to 580 nm, and the Vickers hardness is 620 or more, In terms of oxide, mass % SiO ２ The content of the ingredients is 50.0% to 75.0%. Li ２ The content of O component is 3.0% to 10.0%. Al ２ O ３ The content of the ingredient is 5.0% or more but less than 15.0%; ZrO ２ The content of the component is more than 0% and 10.0% or less, Al ２ O ３ Ingredients and ZrO ２ A crystallized glass having a total content of components of 17.32% or more.

2. In terms of oxide, mass % B ２ O ３ 2. The crystallized glass according to claim 1, wherein the content of the component is 0% to 10.0%.

3. The main crystalline phase contains one or more selected from α-cristobalite and α-cristobalite solid solution, the coloring degree λ80 at a thickness of 10 mm is 330 to 580 nm, and the Vickers hardness is 620 or more, In terms of oxide, mass % SiO ２ The content of the ingredients is 50.0% to 75.0%. Li ２ The content of O component is 3.0% to 10.0%. Al ２ O ３ The content of the ingredient is 10.74% or more but less than 15.0%; ZrO ２ A crystallized glass having a component content of more than 0% and 10.0% or less.

4. In terms of oxide, mass % B ２ O ３ Ingredient content: 0% to 10.0% 4. The crystallized glass according to claim 3, wherein

5. Al in mass% converted to oxide ２ O ３ Ingredients and ZrO ２ 5. The crystallized glass according to claim 3, wherein the total content of the components is 9.5% or more.

6. In terms of oxide, mass % K ２ The content of O component is 0% to 5.0%. P ２ O ５ Ingredient content: 0% to 10.0% 6. The crystallized glass according to claim 1, wherein

7. In terms of oxide, mass % Na ２ The content of O component is 0% to 4.0%. The content of MgO component is 0% to 4.0%. The content of CaO component is 0% to 4.0%. The content of SrO component is 0% to 4.0%. The content of BaO component is 0% to 5.0%; ZnO content is 0% to 10.0%; Sb ２ O ３ Ingredient content: 0% to 3.0% 7. The crystallized glass according to claim 1, wherein:

8. In terms of oxide, mass % Nb ２ O ５ Ingredient content: 0% to 5.0% Ta ２ O ５ Ingredient content: 0% to 6.0% TiO ２ Ingredient content is 0% or more but less than 1.0% 8. The crystallized glass according to claim 1, wherein:

9. 9. The crystallized glass according to claim 1, having a Vickers hardness of 640 or more.

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