Crystallized glass and method for producing crystallized glass

Abstract

To provide silicate glass excellent in chemical durability and having low surface resistivity, and to provide a method for producing the same.SOLUTION: A glass ceramic, comprising a crystalline phase and an amorphous phase, wherein the glass ceramic comprises SiO2, RO, and oxides of an element X, wherein the RO represents oxides of an element R; The element R is one or more elements selected from the group consisting of Mg, Ca, Sr, Ba, and Zn, the element X is one or more elements selected from the group consisting of Nb, Ti, Sn, Ta, W, and Ce, the crystal phase includes one or more crystals containing Si as a constituent element, A value represented by a formula (1a): {(total content ratio of the element X in the amorphous phase) / (total content ratio of the element X in the base glass) * 100} using a total content ratio of the element X in the amorphous phase and a total content ratio of the element X in the base glass of the crystallized glass is more than 100.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a crystallized glass and a method for producing the crystallized glass. [Background technology]

[0002] It is known that an attempt to impart electrical conductivity to glass involves mixing transition metal ions of different valences into the glass. For example, Non-Patent Document 1 describes that when transition metal ions of different valences are mixed into glass, electrons are exchanged between the ions, resulting in electrical conductivity due to hopping conduction. However, the phosphate-based glass described in Non-Patent Document 1 has poor chemical durability and is therefore of little practical use.

[0003] Therefore, even among silicate-based glasses, which have higher chemical durability than phosphate-based glasses, there is a demand for glasses with electronic conductivity. However, although elements such as V, Fe, W, and Mo in Non-Patent Document 1 can easily create a mixed state of different valent ions in phosphate-based glasses, they cannot be immediately applied to silicate-based glasses.

[0004] In response to this, for example, Patent Document 1 proposes a silicate-based glass with low resistivity that contains one or more of six specific components and has a reduced content of alkali metal oxides. Such glass can be obtained by melting the raw materials in a reducing atmosphere. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-043288 [Non-patent literature]

[0006] [Non-Patent Document 1] J.Non-Cryst.Solids, 32, 1979, 91-104 Summary of the Invention [Problem to be solved by the invention]

[0007] In Patent Document 1, low resistivity (volume resistivity) is achieved for the bulk of the glass. However, it has been found that there is room for further reduction in resistivity for the glass disclosed in Patent Document 1, from the viewpoint of increasing applicability to a variety of uses. In particular, for applications such as electronic devices, surface conduction is an important property, and it has been found that further reduction in surface resistivity is necessary.

[0008] Therefore, an object of the present invention is to provide a silicate-based glass having excellent chemical durability and low surface resistivity, and to provide a method for producing a silicate-based glass having excellent chemical durability and low surface resistivity. [Means for solving the problem]

[0009] As a result of intensive research, the present inventors have found that the above-mentioned problems can be solved by forming a crystallized glass containing a specific element X, which can have a different valence, together with another specific element R and SiO2, and by making the total content of the element X in the amorphous phase higher than the total content of the element X in the mother glass, and have thus completed the present invention.

[0010] That is, the gist of the present invention relates to the following [1] to

[14] . [1] A crystallized glass having a crystalline phase and an amorphous phase, The glass-ceramics contains SiO2, RO, and an oxide of element X, The R O represents an oxide of the element R, and the element R is one or more elements selected from the group consisting of Mg, Ca, Sr, Ba, and Zn; The element X is one or more elements selected from the group consisting of Nb, Ti, Sn, Ta, W, and Ce, the crystalline phase contains one or more types of crystals containing Si as a constituent element, Using the total content of the element X in the amorphous phase and the total content of the element X in the mother glass of the crystallized glass, the value represented by formula (1a): {(total content of element X in the amorphous phase) / (total content of element X in the mother glass)×100} is greater than 100. [2] The common logarithm logρ of the surface resistivity of the crystallized glass at 250°C sc250 and the common logarithm logρ of the surface resistivity of the mother glass at 250 ° C. sm250 Using equation (2): {logρ sm250 -logρ sc250} is 4.0 or more. [3] The composition of the crystallized glass is expressed in mole percentage based on oxides, SiO2 30~50%, RO total 30-60% and The crystallized glass according to the above [1] or [2], wherein the oxide of element X is contained in an amount of 8 to 30% in total. [4] The crystallized glass according to any one of the above [1] to [3], wherein the element R is Ba and the element X is Nb. [5] The common logarithm logρ of the surface resistivity of the crystallized glass at 50°C sc50 The crystallized glass according to [4] above, wherein the refractive index is 10.0 (log Ω / □) or less. [6] The common logarithm logρ of the surface resistivity of the crystallized glass at 250°C sc250 The crystallized glass according to [4] or [5] above, wherein the refractive index is 9.0 (log Ω / □) or less. [7] The crystallized glass according to any one of [1] to [6], wherein the crystallized glass contains the crystal phase in an area ratio of 40 to 80% as measured by analysis of an SEM image. [8] The crystallized glass according to any one of [1] to [7], wherein the crystalline phase contains crystals containing Si as the constituent element in an area ratio of 50 to 100% as measured by analysis of an SEM image. [9] The crystallized glass according to any one of [1] to [8], wherein the amorphous phase contains two or more types of ions derived from the element X and having different valences.

[0011]

[10] A method for producing crystallized glass, comprising: Preparing a silicate-based mother glass containing element Y, which is a transition metal element; including heat treatment in a reducing atmosphere, The resulting crystallized glass has a crystalline phase and an amorphous phase, the crystalline phase contains one or more types of crystals containing Si as a constituent element, A method for producing crystallized glass, wherein the value represented by formula (1b): {(total content of element Y in amorphous phase) / (total content of element Y in mother glass)×100} is set to be greater than 100 using the total content of element Y in the amorphous phase and the total content of element Y in the mother glass.

[11] The mother glass contains SiO2, RO, and an oxide of the element Y, The R O represents an oxide of the element R, and the element R is one or more elements selected from the group consisting of Mg, Ca, Sr, Ba, and Zn; The method for producing crystallized glass according to

[10] , wherein the element Y is one or more elements selected from the group consisting of Nb, Ti, Sn, Ta, W, Ce, V, Fe, Mo, and Sb.

[12] The composition of the mother glass is expressed in mole percentage based on oxides: SiO2 30~50%, RO total 30-60% and The method for producing crystallized glass according to

[11] above, wherein the oxide of element Y is 8 to 30% in total.

[13] The method for producing crystallized glass according to any one of

[10] to

[12] above, wherein the heat treatment in a reducing atmosphere includes heat treatment at 800 to 880° C. for 0.1 to 10 hours.

[14] The method for producing crystallized glass according to any one of

[10] to

[13] , wherein the amorphous phase contains two or more types of ions derived from the element Y and having different valences. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a silicate-based glass having excellent chemical durability and low surface resistivity, and also to provide a method for producing a silicate-based glass having excellent chemical durability and low surface resistivity. [Brief explanation of the drawings]

[0013] [Figure 1] Figure 1 shows images of the surface of the glass according to Example 6 obtained by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX). (a) is a backscattered electron (BSE) image obtained by SEM observation. (b), (c), and (d) are elemental mapping images of Si, Ba, and Nb, respectively, obtained by EDX. [Figure 2] Figure 2 shows images of the surface of the glass of Example 10 obtained by SEM-EDX. (a) is a BSE image obtained by SEM observation. (b), (c), and (d) are element mapping images of Si, Ba, and Nb, respectively, obtained by EDX. [Figure 3] 3 shows images of the surface of the glass of Example 11 obtained by SEM-EDX. (a) is a BSE image obtained by SEM observation. (b), (c), and (d) are elemental mapping images of Si, Ba, and Nb, respectively, obtained by EDX. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the embodiments described below. In addition, in this specification, the use of "to" to indicate a range of values ​​means that the values ​​before and after it are included as the lower limit and upper limit.

[0015] <Glass-ceramics> The crystallized glass according to this embodiment has a crystalline phase and an amorphous phase, and contains SiO2, RO, and an oxide of element X. The RO represents an oxide of element R, and the element R is one or more elements selected from the group consisting of Mg, Ca, Sr, Ba, and Zn. The element X is one or more elements selected from the group consisting of Nb, Ti, Sn, Ta, W, and Ce. In the crystallized glass according to this embodiment, the crystalline phase contains one or more types of crystals containing Si as a constituent element. Furthermore, in the crystallized glass according to this embodiment, the value expressed by the formula (1a): {(total content of element X in the amorphous phase) / (total content of element X in the mother glass)×100}, using the total content of element X in the amorphous phase and the total content of element X in the mother glass of the crystallized glass, is more than 100.

[0016] In this specification, the term "crystallized glass having a crystalline phase and an amorphous phase" refers to glass in which diffraction peaks indicating crystals are observed in the XRD pattern obtained by powder X-ray diffraction (XRD). The crystallized glass is obtained by heating amorphous glass (mother glass) in which no diffraction peaks indicating crystals are observed to precipitate crystals.

[0017] In this specification, the composition of the crystallized glass can be identified by a conventionally known method, for example, wet chemical analysis or quantitative analysis using a calibration curve of fluorescent X-rays. Furthermore, the composition of the mother glass before crystals are precipitated and the composition of the entire crystallized glass according to this embodiment after crystals are precipitated can be considered to be the same.

[0018] It is believed that when the content of element X, which can assume a different valence, in the amorphous phase of the crystallized glass is relatively high, the conductivity due to hopping conduction between the elements X becomes better, and as a result, the surface resistivity of the crystallized glass becomes suitably low. Based on the above technical concept, it has been found that the above effect can be more suitably achieved by satisfying the relationship that the value represented by the above formula (1a) regarding the content of element X in the crystallized glass is greater than 100. One way to make the value represented by formula (1a) exceed 100 is to selectively precipitate crystals containing Si as a constituent element in the crystallized glass. This reduces the content of Si, which does not contribute to electronic conductivity, in the amorphous phase, thereby increasing the proportion of element X in the amorphous phase. Even if the crystalline phase of the crystallized glass contains crystals containing element X as a constituent element, the proportion of element X in the amorphous phase can be increased by making the proportion of element X constituting the crystals smaller than the proportion of Si. Note that formula (1a) above shows the relationship between the content of element X in the mother glass and the content of element X in the amorphous phase. However, since the composition of the mother glass and the composition of the crystallized glass are considered to be the same as described above, formula (1a) above can be said to indicate the relative content of element X in the amorphous phase. It is believed that element X is partially reduced by, for example, crystallizing the mother glass by heat treatment in a reducing atmosphere, and as a result, element X is present as two or more types of ions having different valences, i.e., heterovalent ions, in the amorphous phase of the crystallized glass.

[0019] The crystallized glass according to this embodiment contains SiO2, RO, and an oxide of element X. The crystallized glass containing SiO2, RO, and an oxide of element X means that the crystallized glass contains Si, element R, and element X as constituent elements. The composition of the above crystallized glass is expressed in mole percentage based on oxides as follows: SiO2 30~50%, RO total 30-60% and The total content of the oxides of element X is preferably 8 to 30%.

[0020] Each component will be described below. The content of each component is expressed as mole percentage based on the oxide.

[0021] SiO2 is a component that forms the framework of glass and improves the stability and chemical durability of glass, and is also a component that forms crystals. The content of SiO2 in the crystallized glass is preferably 30 to 50%, more preferably 32 to 48%, and even more preferably 34 to 46%. From the viewpoint of improving the stability and chemical durability of the crystallized glass, the content is preferably 30% or more, more preferably 32% or more, and even more preferably 34% or more. Furthermore, from the viewpoint of sufficiently increasing the content of element X and reducing the surface resistivity, the content is preferably 50% or less, more preferably 48% or less, and even more preferably 46% or less.

[0022] RO represents an oxide of element R, where element R is one or more elements selected from the group consisting of Mg, Ca, Sr, Ba, and Zn. When element R is two or more elements selected from the group consisting of Mg, Ca, Sr, Ba, and Zn, RO is a collective term for the oxides of each of those two or more elements. In other words, RO is one or more elements selected from the group consisting of MgO, CaO, SrO, BaO, and ZnO. RO is a component that improves the stability of the crystallized glass. From the viewpoint of further improving the stability of the crystallized glass, the element R is preferably one or more elements selected from the group consisting of Ca, Sr, and Ba, and more preferably Ba.

[0023] The total content of RO (MgO+CaO+SrO+BaO+ZnO) in the crystallized glass is preferably 30 to 60%, more preferably 34 to 58%, and even more preferably 38 to 56%. From the viewpoint of improving the stability of the crystallized glass, the content is preferably 30% or more, more preferably 34% or more, and even more preferably 38% or more. Furthermore, from the viewpoint of increasing the content of element X, the content is preferably 60% or less, more preferably 58% or less, and even more preferably 56% or less.

[0024] When Ba is included as the element R, the content of BaO in the crystallized glass is preferably 30 to 60%, more preferably 34 to 58%, and even more preferably 38 to 56%. From the viewpoint of improving the stability of the crystallized glass, the content is preferably 30% or more, more preferably 34% or more, even more preferably 38% or more, and particularly preferably 40% or more. Furthermore, from the viewpoint of increasing the content of the element X, the content is preferably 60% or less, more preferably 58% or less, even more preferably 56% or less, and particularly preferably 54% or less.

[0025] The element X is an element that can have a different valence and is one or more elements selected from the group consisting of Nb, Ti, Sn, Ta, W, and Ce. When the element X is two or more elements selected from the group consisting of Nb, Ti, Sn, Ta, W, and Ce, the oxide of the element X is a general term for the oxides of each of the two or more elements. Furthermore, when one element X contains two or more ions having different valences, the oxide of the element X is a general term for the oxides formed by each of the two or more ions. The element X is a component that exists in the amorphous phase as two or more types of ions having different valences, thereby imparting electrical conductivity to the crystallized glass and reducing the surface resistivity. From the viewpoint of more suitably reducing the surface resistivity of the crystallized glass, the element X is preferably one or more elements selected from the group consisting of Nb, Ti, and Sn, and more preferably Nb.

[0026] The total content of oxides of element X in the crystallized glass is preferably 8 to 30%, more preferably 9 to 27%, and even more preferably 10 to 24%. From the viewpoint of reducing the surface resistivity of the crystallized glass, the content is preferably 8% or more, more preferably 9% or more, and even more preferably 10% or more. Furthermore, from the viewpoint of improving the stability of the glass, the content is preferably 30% or less, more preferably 27% or less, and even more preferably 24% or less.

[0027] The total content of the oxide of element X refers to the total of values ​​obtained by converting the oxide of element X into Nb2O5 when element X contains Nb, into TiO2 when element X contains Ti, into SnO2 when element X contains Sn, into Ta2O5 when element X contains Ta, into WO3 when element X contains W, and into CeO2 when element X contains Ce.

[0028] When Nb is included as element X, the content of Nb oxide in the crystallized glass (calculated as Nb2O5) is preferably 8 to 30%, more preferably 9 to 27%, and even more preferably 10 to 24%. From the viewpoint of reducing the surface resistivity of the crystallized glass, the content is preferably 8% or more, more preferably 9% or more, and even more preferably 10% or more. Furthermore, from the viewpoint of improving the stability of the glass, the content is preferably 30% or less, more preferably 27% or less, even more preferably 24% or less, and particularly preferably 20% or less.

[0029] From the viewpoint of stably melting and producing glass, it is particularly preferable that the element R is Ba and the element X is Nb.

[0030] In the crystallized glass according to this embodiment, the ratio of the total of RO to SiO2 (RO / SiO2) is preferably 0.6 to 2.0 in terms of the composition expressed in mole percentage based on oxides. From the viewpoint of maintaining chemical durability, the ratio is preferably 0.6 or more, more preferably 0.8 or more, even more preferably 0.9 or more, and particularly preferably 1.0 or more. Furthermore, from the viewpoint of improving the stability of the glass, the ratio is preferably 2.0 or less, more preferably 1.8 or less, and even more preferably 1.6 or less.

[0031] The crystallized glass according to this embodiment may contain components other than those mentioned above, such as one or more components selected from the group consisting of B2O3, Al2O3, Li2O, Na2O, K2O, La2O3, Y2O3, ZrO2, and P2O5.

[0032] B2O3 and P2O5 are components that improve chipping resistance and melting properties. The contents of B2O3 and P2O5 in the crystallized glass are each preferably independently 0 to 10%, more preferably 0.1 to 9%, and even more preferably 0.2 to 8%. Although B2O3 and P2O5 are not necessarily contained, if they are contained, from the viewpoint of obtaining good chipping resistance and meltability, the contents are preferably 0.1% or more, and 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 contents are preferably 10% or less, more preferably 9% or less, and even more preferably 8% or less.

[0033] Al2O3 and ZrO2 are components that increase fracture toughness and strength. The Al2O3 and ZrO2 contents in the crystallized glass are each independently preferably 0.1 to 5%, more preferably 0.5 to 4.5%, and even more preferably 1 to 4%. From the viewpoint of increasing strength, the contents are preferably 0.1% or more, more preferably 0.5% or more, and even more preferably 1% or more. From the viewpoint of glass stability, the contents are preferably 5% or less, more preferably 4.5% or less, and even more preferably 4% or less.

[0034] Li2O, Na2O, or K2O has the effect of promoting the melting of glass, and may be contained, for example, up to 5% in total. If it exceeds 5%, there is a risk of the ionic conductivity becoming strong. If it is desired to suppress the ionic conductivity, it is preferable not to contain Li2O, Na2O, and K2O. The total content of Li2O, Na2O, and K2O may be, for example, 0 to 5%.

[0035] La2O3 or Y2O3 may be contained in a total amount of up to 15% to further stabilize the glass or improve chemical durability. If the amount exceeds 15%, the glass may become unstable. When at least one of La2O3 and Y2O3 is contained, the total content is preferably 1% or more, more preferably 2% or more. The total content of La2O3 and Y2O3 may be, for example, 0 to 15%, 1 to 15%, or 2 to 15%.

[0036] Furthermore, coloring components may be added within a range that does not impede the achievement of the desired properties of the crystallized glass, such as Co3O4, MnO2, NiO, CuO, Cr2O3, Bi2O3, SeO2, Er2O3, and Nd2O3. The total content of the coloring components is preferably 1% or less. If it is desired to increase the light transmittance of the crystallized glass, it is preferable that these components are substantially not contained. In this specification, "substantially free" means that the content is at or below the level of impurities contained in raw materials, etc., that is, that the component is not intentionally added. When it is stated in this specification that a certain component is not substantially contained, the content of the component is specifically, for example, less than 0.03%.

[0037] Furthermore, SO3, chlorides, fluorides, etc. may be appropriately contained as fining agents when melting the glass. It is preferable that As2O3 is not substantially contained.

[0038] The crystallized glass according to this embodiment preferably contains a crystalline phase in an area ratio of 40 to 80% as measured by SEM image analysis. This area ratio represents the crystallization degree of the crystallized glass according to this embodiment. From the viewpoint of more suitably reducing the surface resistivity of the crystallized glass and increasing the mechanical strength of the crystallized glass, the above ratio is preferably 40% or more, more preferably 43% or more, and even more preferably 45% or more. Furthermore, from the viewpoint of maintaining high transmittance and low haze value, the above ratio is preferably 80% or less, more preferably 78% or less, and even more preferably 76% or less. When the crystallized phase contains two or more types of crystals, it is preferable that the total of these crystals satisfies the above range.

[0039] Specifically, the above area ratio can be measured by the following method. For example, an EDX mapping image of Si as shown in Figure 1(b) is prepared, and the image is processed so that the brightness of each pixel is 128 levels. The background brightness is set to the 40th level from the bottom, and the number of pixels with a higher level than that is calculated as a percentage of the total number of pixels in the image. This gives the total area percentage of crystals containing Si as a constituent element (hereinafter also referred to as α-crystals), as described below. When the crystalline phase consists only of α-crystals, the total area percentage of α-crystals calculated by this method corresponds to the area percentage of the crystalline phase in the glass-ceramics. When the crystalline phase further contains one or more types of crystals that do not contain Si as a constituent element (hereinafter also referred to as β crystals), the EDX mapping image of the components precipitated as β crystals, such as element R or element X, is processed in the same manner as above to determine the total area ratio of β crystals. The total area ratio of the β crystals and the total area ratio of the α crystals are added together to determine the area ratio of the crystalline phase in the crystallized glass.

[0040] In the crystallized glass according to this embodiment, the crystal phase contains one or more crystals (α crystals) containing Si as a constituent element. By using such a crystal phase, the value of the formula (1a) described below in the crystallized glass according to this embodiment exceeds 100, and the crystallized glass having low surface resistivity can be provided. Examples of crystals containing Si as a constituent element include SiO2 crystals, and RSiO3 crystals and RSi2O5 crystals, which are composite oxides of Si and element R. Specific examples of RSiO3 crystals and RSi2O5 crystals include barium silicate crystals, strontium silicate crystals, and calcium silicate crystals, depending on the type of element R. Hereinafter, the composite oxide crystals of Si and element R will be referred to as "RSi j O k Also called "crystals."

[0041] The constituent elements of the crystals contained in the crystalline phase can be analyzed by observing the surface of the crystallized glass with an SEM and simultaneously analyzing the characteristic X-rays generated by energy spectroscopy (EDX) to create an elemental mapping.

[0042] The crystalline phase of the crystallized glass according to this embodiment preferably contains crystals (α-crystals) containing Si as the constituent element in an area ratio of 50 to 100% as measured by SEM image analysis. From the viewpoint of more suitably reducing the surface resistivity of the crystallized glass, the ratio is preferably 50% or more, more preferably 55% or more, and even more preferably 60% or more. Furthermore, the higher the ratio, the better, and it may be 100%. In other words, the crystalline phase may consist only of α-crystals. The ratio may be, for example, 95% or less, 90% or less, or 80% or less. When two or more types of crystals are contained as α-crystals, it is preferable that the total of these crystals satisfies the above range.

[0043] Specifically, the above area ratio can be measured using the following method. First, the constituent elements of the crystals contained in the crystalline phase are analyzed using SEM-EDX observation as described above. If the crystalline phase consists only of α crystals, the area ratio of α crystals in the crystalline phase is 100%. On the other hand, if the crystalline phase contains both α crystals and β crystals, the total area ratio of α crystals and the total area ratio of β crystals in the crystallized glass are determined using the image processing method described above. The total area ratio of α crystals in the crystallized glass is converted to the ratio in the crystalline phase using the area ratio of the crystalline phase (i.e., α crystals + β crystals) in the crystallized glass, thereby determining the area ratio of α crystals in the crystalline phase.

[0044] The crystalline phase of the glass-ceramics according to this embodiment is a composite oxide crystal of Si and element R (RSi j O k It is preferable that the crystals (crystals) account for 20 to 100% of the area ratio measured by SEM image analysis. From the viewpoint of more suitably reducing the surface resistivity of the crystallized glass, the ratio is preferably 20% or more, more preferably 30% or more, even more preferably 40% or more, and particularly preferably 50% or more. Furthermore, from the viewpoint of stably obtaining the crystallized glass, the ratio may be 100% or less, preferably 90% or less, more preferably 80% or less, and even more preferably 75% or less.

[0045] Specifically, the above area ratio can be measured by the following method. For example, for an EDX mapping image of element R as shown in Figure 1(c), the above-mentioned image processing method is used to measure the area ratio of RSi in the crystallized glass. j O k The area ratio of the crystals is calculated. This is converted to the ratio in the crystalline phase using the area ratio of the crystalline phase in the glass-ceramic, and RSi in the crystalline phase is calculated. j O k The area ratio of the crystals can be calculated.

[0046] The crystalline phase of the crystallized glass according to this embodiment preferably contains 0 to 80% of SiO2 crystals in terms of area ratio measured by SEM image analysis. Although the ratio may be 0% or more, from the viewpoint of more suitably reducing the surface resistivity of the crystallized glass, the ratio is preferably 5% or more, more preferably 10% or more, and even more preferably 15% or more. Furthermore, from the viewpoint of stably obtaining the crystallized glass, the ratio is preferably 80% or less, more preferably 50% or less, even more preferably 30% or less, and particularly preferably 25% or less.

[0047] The area ratio is, for example, RSi j O k It can be determined by subtracting the area ratio of the crystals from the total area ratio of the α crystals in the crystalline phase described above.

[0048] The crystallized glass according to this embodiment has an area ratio of RSi to SiO2 crystals in the crystal phase measured by analyzing an SEM image. j O k Crystal ratio (RSi j O k It is preferable that the ratio (SiO2 crystal / SiO2 crystal) is 1 to 10. From the viewpoint of increasing the amount of precipitated element R, the ratio is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. Furthermore, from the viewpoint of effectively precipitating Si as a crystalline phase, the ratio is preferably 10 or less, more preferably 8 or less, and even more preferably 7 or less.

[0049] The crystalline phase of the crystallized glass according to this embodiment may further contain one or more crystals containing element X as a constituent element. Examples of the crystals containing element X as a constituent element include RX n O m In order to make the value of formula (1a) exceed 100, it is preferable that the crystalline phase does not contain crystals containing element X as the constituent element.

[0050] The crystalline phase may contain, for example, 10% or less of crystals containing element X as a constituent element, as measured by analyzing an SEM image. From the viewpoint of more suitably reducing the surface resistivity of the crystallized glass, the above proportion is preferably 6% or less, more preferably 3% or less, and most preferably 0%. In other words, it is most preferable that the crystalline phase does not contain crystals containing element X as a constituent element.

[0051] In the crystallized glass according to this embodiment, the value expressed by the formula (1a): {(total content of element X in the amorphous phase) / (total content of element X in the mother glass)×100}, using the total content of element X in the amorphous phase and the total content of element X in the mother glass of the crystallized glass, is more than 100. As described above, the value of the above formula (1a) being greater than 100 indicates that the content of element X, which is an element capable of taking different valences, is higher in the amorphous phase of the crystallized glass than in the mother glass. This allows the crystallized glass according to this embodiment to achieve a low surface resistivity.

[0052] The value of the above formula (1a) is preferably more than 100 and not more than 800, more preferably 103 to 700, and even more preferably 106 to 600. From the viewpoint of more suitably reducing the surface resistivity of the crystallized glass, the value is preferably 103 or more, more preferably 106 or more, and even more preferably 110 or more. Furthermore, from the viewpoint of the stability of the crystallized glass, the value is preferably 800 or less, more preferably 700 or less, and even more preferably 600 or less.

[0053] The total content of element X used in formula (1a) refers to the peak height attributable to element X normalized by the characteristic peak occurring at 0 keV in an EDX spectrum obtained from the amorphous phase of the glass-ceramics or the surface of the mother glass. When two or more elements are contained as element X, the peak height refers to the sum of the peak heights attributable to the respective elements. Here, the total content ratio of element X in mother glass can be measured not only on the surface of mother glass before crystallization, but also by taking a wide measuring area on the surface of crystallized glass.As mentioned above, this is because the composition of mother glass before crystallization and the composition of the crystallized glass of the present embodiment after crystallization can be regarded as the same.

[0054] The amorphous phase of the crystallized glass according to this embodiment preferably contains two or more kinds of ions having different valences derived from the element X. When the amorphous phase contains two or more kinds of ions having different valences derived from the element X, electrons are exchanged between the elements X with different valences, and excellent conductivity is exhibited by hopping conduction, which is thought to result in a low surface resistivity of the crystallized glass.

[0055] When the element X is Nb, the two or more kinds of ions having different valences are, for example, Nb 5+ , Nb 4+ , Nb 3+ , and Nb 2+ The two or more ions having different valences may be Nb5+ , Nb 4+ , and Nb 3+ More preferably, the ions are two or more selected from the group consisting of Nb 5+ and Nb 4+ It is more preferable that:

[0056] When the element X is Ti, the two or more kinds of ions having different valences are, for example, Ti 4+ , Ti 3+ , Ti 2+ , and Ti + The two or more types of ions having different valences may be selected from the group consisting of Ti 4+ , Ti 3+ , and Ti 2+ More preferably, the ions are two or more types selected from the group consisting of Ti 4+ and Ti 3+ It is more preferable that:

[0057] When the element X is Sn, the two or more kinds of ions having different valences are, for example, Sn 4+ and Sn 2+ It may be.

[0058] When the element X is Ta, the two or more kinds of ions having different valences are, for example, Ta 5+ , Ta 4+ , Ta 3+ , and Ta 2+ The two or more ions having different valences may be selected from the group consisting of Ta 5+ , Ta 4+ , and Ta 3+ More preferably, the ions are two or more selected from the group consisting of Ta 5+ and Ta 4+ It is more preferable that:

[0059] When the element X is W, the two or more kinds of ions having different valences are, for example, W 6+ , W 5+ , W4+ , W 3+ , W 2+ , and W + The two or more ions having different valences may be selected from the group consisting of W 6+ , W 5+ , and W 4+ More preferably, the ions are two or more types selected from the group consisting of W 6+ and W 5+ It is more preferable that:

[0060] When the element X is Ce, the two or more kinds of ions having different valences are, for example, Ce 4+ , Ce 3+ , and Ce 2+ The two or more ions having different valences may be selected from the group consisting of Ce, 4+ and Ce 3+ It is preferable that:

[0061] In the crystallized glass according to this embodiment, the common logarithm logρ of the surface resistivity of the crystallized glass at 250°C sc250 and the common logarithm logρ of the surface resistivity of the above mother glass at 250 ° C. sm250 Using equation (2): {logρ sm250 -logρ sc250 When the value of formula (2) is 4.0 or more, it can be said that the amorphous phase of the crystallized glass contains two or more types of ions derived from the element X and having different valences. From the viewpoint of further reducing the surface resistivity of the crystallized glass, the value of the above formula (2) is preferably 4.0 or more, more preferably 5.0 or more, and even more preferably 6.0 or more. The upper limit of the value of formula (2) is not particularly limited, but is usually 15.0 or less. The value of formula (2) may be, for example, 4.0 to 15.0.

[0062] The surface resistivity of the above-mentioned crystallized glass and mother glass at 250°C can be measured in accordance with ASTM D257-07. Since the surface resistivity at room temperature or around 50°C may exceed the measurement limit, the surface resistivity at 250°C, at which the surface resistivity tends to be low, is used as an index to obtain a comparable value that can be used in the above formula (2).

[0063] Furthermore, the common logarithm logρ of the surface resistivity at 50° C. of the crystallized glass according to this embodiment sc50 From the viewpoint of providing a crystallized glass having a low surface resistivity, the common logarithm of the surface resistivity, logρ, is preferably 11.0 (logΩ / □) or less. sc50 is preferably 11.0 (logΩ / □) or less, more preferably 10.0 (logΩ / □) or less, even more preferably 9.0 (logΩ / □) or less, and particularly preferably 8.0 (logΩ / □) or less. sc50 The lower limit of the common logarithm of the surface resistivity, logρ, is not particularly limited, but may be, for example, 0 or more. sc50 can be adjusted by, for example, the composition of the crystallized glass or the heat treatment conditions during crystallization.

[0064] The surface resistivity of the above crystallized glass at 50°C can be measured in accordance with ASTM D257-07. To avoid variations in measurement values ​​due to variations in room temperature, the surface resistivity at 50°C after heating from room temperature is used as an index.

[0065] Furthermore, the common logarithm logρ of the surface resistivity at 250° C. of the crystallized glass according to this embodiment sc250 From the viewpoint of providing a crystallized glass having a low surface resistivity, the common logarithm of the surface resistivity, logρ, is preferably 10.0 (logΩ / □) or less. sc250 is preferably 10.0 (logΩ / □) or less, more preferably 9.0 (logΩ / □) or less, even more preferably 8.0 (logΩ / □) or less, and particularly preferably 7.0 (logΩ / □) or less. sc250The lower limit of the common logarithm of the surface resistivity, logρ, is not particularly limited, but may be, for example, 0 or more. sc250 can be adjusted by, for example, the composition of the crystallized glass or the heat treatment conditions during crystallization. The surface resistivity of the above crystallized glass at 250° C. can be measured in accordance with ASTM D257-07 as described above.

[0066] When the element R contained in the crystallized glass according to this embodiment is Ba and the element X is Nb, the common logarithm log of the surface resistivity of the crystallized glass at 50° C. ρsc50 From the viewpoint of providing a crystallized glass having a low surface resistivity, the common logarithm of the surface resistivity, log ρsc50 is preferably 10.0 (logΩ / □) or less, more preferably 9.5 (logΩ / □) or less, and even more preferably 9.0 (logΩ / □) or less. ρsc50 The lower limit of is not particularly limited, but may be, for example, 0 or more.

[0067] When the element R contained in the crystallized glass according to this embodiment is Ba and the element X is Nb, the common logarithm log of the surface resistivity of the crystallized glass at 250°C is ρsc250 From the viewpoint of providing a crystallized glass having a low surface resistivity, the common logarithm of the surface resistivity, log ρsc250 is preferably 9.0 (logΩ / □) or less, more preferably 8.0 (logΩ / □) or less, and even more preferably 7.0 (logΩ / □) or less. ρsc250 The lower limit of is not particularly limited, but may be, for example, 0 or more.

[0068] The composition of the amorphous phase of the crystallized glass according to this embodiment is expressed in mole percentage based on oxides as follows: SiO2 2~40%, RO total 5-40% and The oxides of element X preferably account for 20 to 93% in total.

[0069] <<Method for producing glass-ceramics>> The method for producing crystallized glass according to this embodiment includes preparing a silicate-based mother glass containing a transition metal element Y, and heat-treating it in a reducing atmosphere. The crystallized glass obtained by this method has a crystalline phase and an amorphous phase, and the crystalline phase contains one or more types of crystals containing Si as a constituent element. In addition, in the method for producing crystallized glass according to this embodiment, the value expressed by the formula (1b): {(the total content of element Y in the amorphous phase) / (the total content of element Y in the mother glass)×100} is set to be greater than 100, using the total content of element Y in the amorphous phase of the crystallized glass obtained and the total content of element Y in the mother glass.

[0070] The silicate-based mother glass refers to an amorphous glass containing a silicate as a component. The silicate is not particularly limited, but examples thereof include alkaline earth-containing silicate glass and alkaline earth-containing borosilicate glass.

[0071] The above-mentioned mother glass can be obtained by a conventionally known method. That is, when obtaining a plate-shaped amorphous glass, for example, glass raw materials are mixed to obtain a desired composition, and heated and melted in a glass melting furnace.Then, the molten glass is homogenized by bubbling, stirring, adding a clarifier, etc., and formed into a glass plate of a predetermined thickness by a known forming method, and then slowly cooled.Alternatively, the molten glass may be formed into a block shape, slowly cooled, and then cut into a plate shape. Examples of methods for forming plate glass include the float method, the press method, the fusion method, and the down-draw method.

[0072] The mother glass preferably contains SiO2, RO, and an oxide of the element Y. Here, RO represents an oxide of the element R, and the element R is preferably one or more elements selected from the group consisting of Mg, Ca, Sr, Ba, and Zn. The mother glass containing SiO2, RO, and an oxide of the element Y means that the mother glass contains Si, the element R, and the element Y as constituent elements. Furthermore, the composition of the above-mentioned mother glass is expressed in mole percentage based on oxides as follows: SiO2 30~50%, RO total 30-60% and The total content of oxides of element Y is preferably 8 to 30%. As described above, the composition of the mother glass before crystal precipitation can be considered to be the same as the composition of the entire crystallized glass obtained by the method for producing crystallized glass according to this embodiment.

[0073] The roles and preferred content ratios of SiO2 and RO, and the preferred range of the ratio of the total of RO to SiO2 (RO / SiO2) are the same as those described above for the composition of crystallized glass in <Ceramics>.

[0074] The element Y is a transition metal element. In this specification, the transition metal element refers to an element in Groups 3 to 11 of the periodic table. The element Y is preferably one or more elements selected from the group consisting of Nb, Ti, Sn, Ta, W, Ce, V, Fe, Mo, and Sb, and more preferably the element X, i.e., one or more elements selected from the group consisting of Nb, Ti, Sn, Ta, W, and Ce. When the element Y is two or more elements, the oxide of the element Y is a general term for the oxides of each of the two or more elements. Furthermore, when one element Y contains two or more ions having different valences, the oxide of the element Y is a general term for the oxides formed by each of the two or more ions. The element Y is a component that exists as two or more ions having different valences in the amorphous phase of the crystallized glass obtained by the method for producing the crystallized glass according to this embodiment, thereby providing conductivity to the crystallized glass and reducing the surface resistivity.From the viewpoint of more suitably reducing the surface resistivity of the crystallized glass, the element Y is preferably one or more elements selected from the group consisting of Nb, Ti, and Sn, and more preferably Nb.

[0075] The total content of oxides of element Y in the mother glass is preferably 8 to 30%, more preferably 9 to 27%, and even more preferably 10 to 24%. From the viewpoint of reducing the surface resistivity of the crystallized glass, the content is preferably 8% or more, more preferably 9% or more, and even more preferably 10% or more. Furthermore, from the viewpoint of improving the stability of the glass, the content is preferably 30% or less, more preferably 27% or less, and even more preferably 24% or less.

[0076] The total content ratio of the oxide of element Y refers to the sum of the values ​​obtained by converting the oxide of element Y into Nb2O5 when element Y contains Nb, into TiO2 when element Y contains Ti, into SnO2 when element Y contains Sn, into Ta2O5 when element Y contains Ta, into WO3 when element Y contains W, into CeO2 when element Y contains Ce, into V2O5 when element Y contains V, into Fe2O3 when element Y contains FeO3 when element Y contains Mo, and into Sb2O5 when element Y contains Sb.

[0077] When Nb is included as the element Y, the content of Nb oxide in the mother glass (calculated as Nb2O5) is preferably 8 to 30%, more preferably 9 to 27%, and even more preferably 10 to 24%. From the viewpoint of reducing the surface resistivity of the crystallized glass, the content is preferably 8% or more, more preferably 9% or more, and even more preferably 10% or more. Furthermore, from the viewpoint of improving the stability of the glass, the content is preferably 30% or less, more preferably 27% or less, even more preferably 24% or less, and particularly preferably 20% or less.

[0078] From the viewpoint of stably melting and producing glass, it is particularly preferable that the element R is Ba and the element Y is Nb.

[0079] Components other than those mentioned above, coloring components, and fining agents that may be contained in the mother glass, and their preferred content ratios are the same as those described above for the composition of the crystallized glass in <<Crystallized Glass>>.

[0080] The method for producing crystallized glass according to this embodiment includes at least a heat treatment in a reducing atmosphere, and may include, for example, any of the following steps (I) to (III). (I) The mother glass is heat-treated in a reducing atmosphere. (II) The mother glass is heat-treated in a non-reducing atmosphere and then heat-treated in a reducing atmosphere. (III) The mother glass is heat-treated in a reducing atmosphere and then heat-treated in a non-reducing atmosphere. The glass is crystallized by heat treatment in a reducing atmosphere in the above (I) or by heat treatment in a non-reducing atmosphere in the above (II) and (III). By this method, one or more crystals containing Si as a constituent element are precipitated in the crystalline phase of the obtained crystallized glass, and the value represented by the above formula (1b) exceeds 100. Furthermore, it is believed that the element Y is partially reduced by the heat treatment in the reducing atmosphere in the above (I) to (III), and thus exists as two or more types of ions having different valences in the amorphous phase of the resulting crystallized glass, which is believed to result in a crystallized glass with low surface resistivity. That is, in the above (I), the mother glass is crystallized and the element Y in the mother glass is reduced simultaneously; in the above (II), the mother glass is crystallized, and then the element Y in the resulting glass is reduced; and in the above (III), the element Y in the mother glass is reduced, and then the resulting glass is crystallized.

[0081] <Heat treatment in a reducing atmosphere> In the method for producing crystallized glass according to this embodiment, a gas having reducing power is used to perform heat treatment in a reducing atmosphere. Examples of the gas having reducing power include hydrogen gas, carbon monoxide gas, and hydrocarbon gas. From the viewpoints of safety and atmosphere controllability, the gas having reducing power is preferably hydrogen gas.

[0082] During heat treatment in a reducing atmosphere, the content of the gas having the reducing power in the atmosphere is preferably 1 to 100% by volume, more preferably 2 to 80% by volume, and even more preferably 5 to 50% by volume. From the viewpoint of enhancing the reducibility of element Y, the content is preferably 1% by volume or more, more preferably 2% by volume or more, and even more preferably 5% by volume or more. From the viewpoint of safety, the content is preferably 100% by volume or less, more preferably 80% by volume or less, and even more preferably 50% by volume or less.

[0083] When hydrogen gas is used as the gas having reducing power, the content of the hydrogen gas in the atmosphere during the heat treatment is preferably 1 to 100% by volume, more preferably 2 to 80% by volume, and even more preferably 5 to 50% by volume. From the viewpoint of enhancing the reducibility of element Y, the content is preferably 1% by volume or more, more preferably 2% by volume or more, and even more preferably 5% by volume or more. From the viewpoint of safety, the content is preferably 100% by volume or less, more preferably 80% by volume or less, and even more preferably 50% by volume or less.

[0084] The atmosphere during the heat treatment in a reducing atmosphere may contain, in addition to the gas having reducing power, an inert gas such as nitrogen gas, argon gas, or helium gas. The atmosphere during the heat treatment may be, for example, 10% by volume of hydrogen gas and 90% by volume of nitrogen gas.

[0085] In the method for producing crystallized glass according to the present embodiment, the heating device is sealed in order to carry out the heat treatment in a reducing atmosphere. Specifically, it is preferable to replace the atmosphere in the heating device (for example, an electric furnace) with a gas having reducing power at room temperature, seal the heating device, and then carry out the heat treatment.

[0086] The heat treatment temperature in the reducing atmosphere is preferably 800 to 880°C, more preferably 805 to 875°C, and even more preferably 810 to 870°C. From the viewpoint of promoting crystallization and simultaneously enhancing the reducibility of element Y, the heat treatment temperature is preferably 800°C or higher, more preferably 805°C or higher, and even more preferably 810°C or higher. Furthermore, from the viewpoint of reducing energy consumption during production, the heat treatment temperature is preferably 880°C or lower, more preferably 875°C or lower, and even more preferably 870°C or lower. From the viewpoint of promoting crystallization and simultaneously enhancing the reducibility of element Y, the heat treatment is preferably carried out at a temperature of (Tg+30°C) or higher, where Tg is the glass transition temperature of the mother glass. The heat treatment is more preferably carried out at a temperature of (Tg+30°C) to (Tg+150°C), and even more preferably at a temperature of (Tg+40°C) to (Tg+130°C).

[0087] In the method for producing crystallized glass according to this embodiment, the glass may be heated, for example, from room temperature to the heat treatment temperature in the reducing atmosphere at a single temperature increase rate, or may be heated at two or more temperature increase rates.

[0088] As described above, when glass is heated to the heat treatment temperature in a reducing atmosphere at a single heating rate, the heating rate is preferably +0.1 to +100°C / min, more preferably +0.5 to +50°C / min, and even more preferably +1 to +30°C / min, from the viewpoint of temperature stability. On the other hand, when glass is heated to the heat treatment temperature at two heating rates, the heating rate in the first stage is designated as the first heating rate and the heating rate in the second stage is designated as the second heating rate, and the first heating rate is preferably in the same range as the above heating rate, and the second heating rate is preferably slower than the first heating rate.

[0089] In the method for producing crystallized glass according to this embodiment, the glass may be cooled from the heat treatment temperature in the reducing atmosphere to, for example, room temperature at a single cooling rate, or may be cooled at two or more cooling rates.

[0090] As described above, when the glass is cooled from the heat treatment temperature in a reducing atmosphere at a single cooling rate, the cooling rate is preferably −0.1 to −100° C. / min, more preferably −0.5 to −50° C. / min, and even more preferably −1 to −30° C. / min, from the viewpoint of temperature stability. On the other hand, when the glass is cooled from the heat treatment temperature at two cooling rates, the cooling rate in the first stage is designated as the first cooling rate and the cooling rate in the second stage is designated as the second cooling rate, and the second cooling rate is preferably in the same range as the above cooling rates, and the absolute value of the first cooling rate is preferably smaller than that of the second cooling rate.

[0091] The heat treatment time in the reducing atmosphere is preferably 0.1 to 10 hours, more preferably 0.3 to 9 hours, and even more preferably 0.5 to 8 hours. From the viewpoint of promoting crystallization and simultaneously enhancing the reducibility of element Y, the heat treatment time is preferably 0.1 hour or more, more preferably 0.3 hour or more, and even more preferably 0.5 hour or more. Furthermore, from the viewpoint of reducing energy consumption during production, the heat treatment time is preferably 10 hours or less, more preferably 9 hours or less, and even more preferably 8 hours or less.

[0092] The heat treatment in the reducing atmosphere preferably includes heat treatment at 800 to 880° C. for 0.1 to 10 hours, more preferably includes heat treatment at 805 to 875° C. for 0.3 to 9 hours, and even more preferably includes heat treatment at 810 to 870° C. for 0.5 to 8 hours. For example, when the heat treatment temperature is low, a long heat treatment time is preferable, and when the heat treatment temperature is high, a short heat treatment time is sufficient.

[0093] <Heat treatment in a non-reducing atmosphere> The method for producing crystallized glass according to this embodiment may include heat treatment in a non-reducing atmosphere, as in the above (II) and (III). The non-reducing atmosphere in the heat treatment is not particularly limited as long as it does not contain the gas having the reducing power. The heat treatment temperature, the rate of temperature rise to the heat treatment temperature, the rate of cooling from the heat treatment temperature, the heat treatment time, and the combination of the heat treatment temperature and time during the heat treatment in a non-reducing atmosphere are preferably the same as those in the ranges described above in <Heat treatment in a reducing atmosphere>.

[0094] In the manufacturing method of crystallized glass according to the present embodiment, the crystalline phase of the crystallized glass that can be obtained comprises one or more kinds of crystals (α crystals) that contain Si as a constituent element.The crystals that contain Si are the same as those described above in "crystallized glass". In addition, in the crystallized glass obtained by the method for producing crystallized glass according to this embodiment, the area ratio of the crystalline phase; the area ratio of α crystals, the area ratio of SiO2 crystals, and RSi j O k Crystal area ratio; and RSi j O k The preferred range of the ratio of crystals to SiO2 crystals is the same as that described above in "Ceramics".

[0095] In the method for producing crystallized glass according to this embodiment, the value expressed by the formula (1b): {(the total content of element Y in the amorphous phase) / (the total content of element Y in the mother glass)×100} is set to be greater than 100, using the total content of element Y in the amorphous phase of the crystallized glass obtained and the total content of element Y in the mother glass. The value of the above formula (1b) being more than 100 indicates that the content of element Y, which is an element that can have a different valence, is higher in the amorphous phase of the glass-ceramics than in the mother glass. This allows the glass-ceramics obtained by the method for producing glass-ceramics according to this embodiment to achieve a low surface resistivity.

[0096] The value of the above formula (1b) is preferably more than 100 to 800, more preferably 103 to 700, and even more preferably 106 to 600. From the viewpoint of further reducing the surface resistivity of the crystallized glass, the value is preferably 103 or more, more preferably 106 or more, and even more preferably 110 or more. Furthermore, from the viewpoint of the stability of the crystallized glass, the value is preferably 800 or less, more preferably 700 or less, and even more preferably 600 or less.

[0097] The total content of element Y used in formula (1b) refers to the peak height attributable to element Y normalized by the characteristic peak occurring at 0 keV in an EDX spectrum obtained from the amorphous phase of the glass-ceramics or the surface of the mother glass. When two or more elements are contained as element Y, the peak height refers to the sum of the peak heights attributable to each element.

[0098] The amorphous phase of the crystallized glass obtained by the method for producing the crystallized glass according to this embodiment preferably contains two or more kinds of ions having different valences derived from the element Y. When the amorphous phase contains two or more kinds of ions having different valences derived from the element Y, electrons are exchanged between the elements Y having different valences, and excellent conductivity is exhibited by hopping conduction, which is thought to result in a low surface resistivity of the crystallized glass.

[0099] When the element Y is Nb, Ti, Sn, Ta, W, or Ce, specific examples of the two or more types of ions having different valences are the same as those described above for the element X in "Ceramics."

[0100] When the element Y is V, the two or more kinds of ions having different valences are, for example, V 5+ , V 4+ , V 3+ , V 2+ , and V + The two or more ions having different valences may be selected from the group consisting of V 5+ , V 4+ , and V 3+More preferably, the ions are two or more selected from the group consisting of V 5+ and V 4+ It is more preferable that:

[0101] When the element Y is Fe, the two or more kinds of ions having different valences are, for example, Fe 6+ , Fe 5+ , Fe 4+ , Fe 3+ , Fe 2+ , and Fe + The two or more ions having different valences may be selected from the group consisting of Fe 3+ , Fe 2+ , and Fe + More preferably, the ions are two or more selected from the group consisting of Fe 3+ and Fe 2+ It is more preferable that:

[0102] When the element Y is Mo, the two or more kinds of ions having different valences are, for example, Mo 6+ , Mo 5+ , Mo 4+ , Mo 3+ , Mo 2+ , and Mo + The two or more ions having different valences may be selected from the group consisting of Mo 6+ , Mo 5+ , and Mo 4+ More preferably, the ions are two or more selected from the group consisting of Mo 6+ and Mo 5+ It is more preferable that:

[0103] For the crystallized glass obtained by the method for producing the crystallized glass according to this embodiment, the preferred range of the value of formula (2) and the preferred range of the common logarithm of the surface resistivity are the same as those described above in "Crystallized Glass". [Example]

[0104] The present invention will be described below with reference to examples, but the present invention is not limited thereto. Examples 5 to 7 and 11 are working examples, and Examples 1 to 4 and 8 to 10 are comparative examples.

[0105] <Test Example> Example 1 The glass raw materials were mixed to obtain a glass composition of 37.5% SiO2, 50% BaO, and 12.5% ​​Nb2O5 in mole percentages based on oxides, and weighed to obtain 400 g of glass. The mixed glass raw materials were then placed in a platinum crucible and placed in an electric furnace at 1500°C, where they were melted for approximately 5 hours, degassed, and homogenized. The obtained molten glass was poured into a mold and kept at 760°C for 1 hour, and then cooled to room temperature at a rate of 1°C / min to obtain a glass block. The obtained glass block was processed into a 50 mm × 50 mm × 1.5 mm plate to obtain amorphous mother glass. The thermal expansion curve of the obtained glass was measured using a differential thermal dilatometer, and the glass transition temperature was calculated from the inflection point, which was 755°C.

[0106] Example 2 The plate-shaped mother glass obtained in Example 1 was placed on an alumina plate, placed in an electric furnace, sealed, and subjected to heat treatment in an air atmosphere at 835°C for 6 hours. Specifically, the glass of Example 1 was heated in an air atmosphere at a rate of +20°C / min to 650°C, and then further heated at a rate of +2°C / min to 835°C. The glass was then held at 835°C for 6 hours for heat treatment. After completion of the heat treatment, the glass was cooled to 650°C at a rate of -2°C / min, and further cooled to room temperature at a rate of -20°C / min. This yielded the glass of Example 2.

[0107] <Examples 3 to 11> The glasses of Examples 3 to 11 were obtained in the same manner as in Example 2, except that the heat treatment atmosphere was changed to a reducing atmosphere containing 10% by volume of hydrogen gas and 90% by volume of nitrogen gas, and the heat treatment temperature and time were changed to the temperatures and times shown in Table 1.

[0108] "evaluation" <Types of crystals> The glass surfaces of Examples 1 to 11 were analyzed for the presence or absence of crystals precipitated, and if crystals were precipitated, their types were analyzed. Specifically, the glass surface was irradiated with X-rays, and the appearance of crystal peaks was confirmed by diffraction. The measurement angle range was 10° to 100°, and scanning was performed at 20° per minute. When peaks appeared, the precipitated crystals were identified by checking against the JCPDS card. In the glasses of Examples 1 to 11, crystals not containing Si as a constituent element (β crystals) were not precipitated.

[0109] <Surface resistivity> For the glasses of Examples 1 to 11, the common logarithm logρ of the surface resistivity at 50 ° C. and 250 ° C. sc50 and logρ sc250 was measured and calculated in accordance with ASTM D257-07.

[0110] <Value of formula (2)> For the glasses of Examples 1 to 11, the formula (2): {logρ sm250 -logρ sc250 The value represented by the common logarithm logρ of the surface resistivity of the mother glass at 250°C was calculated. sm250 is the log ρ of Example 1 calculated in the above <Surface resistivity>. sc250 The log ρ of Examples 1 to 11 was used. sc250 The value calculated in the above <Surface resistivity> was used as the surface resistivity.

[0111] <Value of formula (1a)> The value of formula (1a) was calculated for the glasses of Examples 6, 10, and 11. That is, the value represented by formula (1a): {(total content of element X in the amorphous phase) / (total content of element X in the mother glass) × 100} was calculated using the total content of element X in the amorphous phase of the glass and the total content of element X in the mother glass. In Examples 6, 10, and 11, element X is Nb. Therefore, in these examples, formula (1a) is consistent with formula (1b) in the method for producing crystallized glass. Specifically, the amorphous phase or base glass surface of each of Examples 6, 10, and 11 was observed using an SEM at an acceleration voltage of 7 kV and a magnification of 10,000x. At the same time, the characteristic X-rays generated were analyzed by energy spectroscopy (EDX) to create an elemental mapping. From the obtained EDX mapping, points from which data was obtained were selected, and EDX spectra were obtained. To enable comparison of peak heights between the amorphous phase of the glass-ceramics and the base glass, the peak heights derived from Nb were normalized by the characteristic peak generated at 0 keV. This procedure was performed for three representative points in each EDX mapping. The normalized peak heights derived from Nb were obtained for the three points, and the average value was used as the "total content ratio of element X (Nb) in the amorphous phase" or the "total content ratio of element X (Nb) in the base glass" in the above formula (1a) to calculate the value of formula (1a). As shown in Table 2, the values ​​of formula (1a) for the glasses of Examples 6 and 11 were greater than 100. Note that, for the glasses of Examples 5 and 7, SiO2 crystals and BaSiO3 crystals were also confirmed as surface precipitated crystals, and it is therefore reasonably presumed that the proportion of element X (Nb in this example) in the amorphous phase is relatively high, i.e., the values ​​of formula (1a) are greater than 100.

[0112] Images of the glass surfaces of Examples 6, 10, and 11 obtained by the above procedure are shown in Figures 1 to 3. In each figure, (a) is a backscattered electron (BSE) image obtained by SEM observation. (b), (c), and (d) are elemental mapping images of Si, Ba, and Nb, respectively, obtained by EDX. In (b), (c), and (d) of each figure, the brighter areas indicate areas with higher peak heights (higher content) attributable to the target element. In Figure 1 (Example 6) and Figure 3 (Example 11), it was confirmed that SiO2 crystals were at the center and BaSiO3 crystals were precipitated around them to form a crystalline phase. It was confirmed that the Nb content was relatively high in the amorphous phase around the crystalline phase, that is, Nb was concentrated, and it was inferred that the amorphous phase was connected three-dimensionally. On the other hand, in Figure 2 (Example 10), it was also confirmed that BaSiO3 crystals were precipitated around a small amount of SiO2 crystals. However, because the degree of crystallization was extremely low, no crystal peaks could be detected by X-ray diffraction, and the Nb content in the amorphous phase was equivalent to the Nb content in the mother glass.

[0113] <Crystalline phases and area ratio of each crystal> For the glasses of Examples 6, 10, and 11, the crystallinity, i.e., the area ratio of the crystalline phase; the area ratio of crystals containing Si as a constituent element (α crystals) in the crystalline phase, the area ratio of SiO2 crystals, and the area ratio of BaSiO3 crystals; and the ratio of BaSiO3 crystals to SiO2 crystals were measured and calculated as follows. The EDX mapping images of Si shown in Figures 1(b), 2(b), and 3(b) were image-processed so that each pixel brightness was 128 levels. The background brightness was defined as the 40th level from the bottom, and the number of pixels with a higher brightness level was calculated as the percentage of the total number of pixels in the image. As mentioned above, in the glasses of Examples 6, 10, and 11, no crystals not containing Si as a constituent element (β crystals) were precipitated. Therefore, the area percentage of α crystals in the glass calculated in this manner coincided with the area percentage of the crystalline phase in the glass. For the same reason, the area percentage of α crystals in the crystalline phase was 100%. The EDX mapping images of Ba shown in Figures 1(c), 2(c), and 3(c) were processed in the same manner as above and converted into the proportion in the crystalline phase to determine the area proportion of BaSiO3 crystals in the crystalline phase. The area proportion of SiO2 crystals in the crystalline phase was determined by subtracting the area proportion of BaSiO3 crystals in the crystalline phase from the area proportion of α crystals in the crystalline phase (100%). The ratio between the area proportion of BaSiO3 crystals and the area proportion of SiO2 crystals obtained as described above was calculated.

[0114] The heat treatment conditions for the glasses prepared in Examples 1 to 11 are shown in Table 1. The types of crystals precipitated on the surface of the glasses prepared in Examples 1 to 11, the surface resistivity (logρ sc50 and logρ sc250 The results of analyzing and measuring the value of formula (1a) and the value of formula (2) are shown in Table 1. Furthermore, the results of measuring and calculating the value of formula (1a) and the area ratios of the crystalline phases and each crystal for the glasses prepared in Examples 6, 10, and 11 above are shown in Table 2.

[0115] [Table 1]

[0116] [Table 2]

[0117] From the above results, it was found that the crystallized glass according to this embodiment was able to achieve low surface resistivity in silicate-based glass.

Claims

1. A crystallized glass having a crystalline phase and an amorphous phase, The crystallized glass is SiO ２ , RO, and an oxide of element X, RO represents an oxide of an element R, and the element R is one or more elements selected from the group consisting of Mg, Ca, Sr, Ba, and Zn; The element X is one or more elements selected from the group consisting of Nb, Ti, Sn, Ta, W, and Ce, the crystalline phase includes one or more types of crystals containing Si as a constituent element, Using the total content of element X in the amorphous phase and the total content of element X in a mother glass of the crystallized glass, a value expressed by formula (1a): {(total content of element X in the amorphous phase) / (total content of element X in the mother glass)×100} is more than 100.

2. The common logarithm log ρ of the surface resistivity of the crystallized glass at 250 ° C. ｓｃ２５０ and the common logarithm logρ of the surface resistivity of the mother glass at 250 ° C. ｓｍ２５０ Using the formula (2): {log ρ ｓｍ２５０ -logρ ｓｃ２５０ 2. The crystallized glass according to claim 1, wherein the value represented by (2) is 4.0 or more.

3. The composition of the crystallized glass is expressed in mole percentage based on oxides as follows: Yes ２ 30-50%, RO total 30-60%, and 3. The crystallized glass according to claim 1, wherein the total content of oxides of element X is 8 to 30%.

4. 3. The crystallized glass according to claim 1, wherein the element R is Ba and the element X is Nb.

5. The common logarithm log ρ of the surface resistivity of the crystallized glass at 50 ° C. ｓｃ５０ The crystallized glass according to claim 4, wherein the crystallization coefficient is 10.0 (log Ω / □) or less.

6. The common logarithm log ρ of the surface resistivity of the crystallized glass at 250 ° C. ｓｃ２５０ The crystallized glass according to claim 4, wherein the crystallization coefficient is 9.0 (log Ω / □) or less.

7. 3. The crystallized glass according to claim 1, wherein the crystal phase accounts for 40 to 80% of the crystallized glass as measured by SEM image analysis.

8. 3. The crystallized glass according to claim 1, wherein the crystalline phase contains crystals containing Si as the constituent element in an area ratio of 50 to 100% as measured by analysis of an SEM image.

9. 3. The crystallized glass according to claim 1, wherein the amorphous phase contains two or more types of ions derived from the element X and having different valences.

10. A method for producing crystallized glass, comprising: Preparing a silicate-based mother glass containing element Y, which is a transition metal element; including heat treatment in a reducing atmosphere, The resulting crystallized glass has a crystalline phase and an amorphous phase, the crystalline phase includes one or more types of crystals containing Si as a constituent element, A method for producing crystallized glass, wherein the value represented by formula (1b): {(total content of element Y in the amorphous phase) / (total content of element Y in the mother glass)×100} is set to be greater than 100 using the total content of element Y in the amorphous phase and the total content of element Y in the mother glass.

11. The mother glass is SiO ２ , RO, and the oxide of the element Y, RO represents an oxide of an element R, and the element R is one or more elements selected from the group consisting of Mg, Ca, Sr, Ba, and Zn; 11. The method for producing crystallized glass according to claim 10, wherein the element Y is one or more elements selected from the group consisting of Nb, Ti, Sn, Ta, W, Ce, V, Fe, Mo, and Sb.

12. The composition of the mother glass is expressed in mole percentage based on oxides: Yes ２ 30-50%, RO total 30-60%, and The method for producing crystallized glass according to claim 11, wherein the total amount of oxides of element Y is 8 to 30%.

13. 12. The method for producing crystallized glass according to claim 10, wherein the heat treatment in a reducing atmosphere includes a heat treatment at 800 to 880° C. for 0.1 to 10 hours.

14. 12. The method for producing crystallized glass according to claim 10, wherein the amorphous phase contains two or more types of ions derived from the element Y and having different valences.

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