Black quartz glass and method of making same

Abstract

The present invention relates to a black quartz glass, a manufacturing method of the black quartz glass, and an article including a black quartz glass member using the above black quartz glass, the above black quartz glass including a composition of SiO2 of 63 to 65 mass%, TiO2 of 18 to 24 mass%, and Al2O3 of 12 to 17 mass% (total of SiO2, TiO2, and Al2O3 is 100 mass%), the above manufacturing method including mixing SiO2 powder of 63 to 65 mass%, TiO2 powder of 18 to 24 mass%, and Al2O3 powder of 12 to 17 mass%, filling the mixed powder in a mold, melting the same at a maximum temperature of 1700 to 1900°C in an oxygen-free atmosphere, and cooling to room temperature to obtain the above black quartz glass. The present invention provides a black quartz glass having excellent light shielding property, not causing contamination in a use process, having sufficient color uniformity when large-sized, enabling production of a large ingot, a method of manufacturing the black quartz glass with excellent productivity even for a large ingot, and a black quartz glass article using the same.

Description

TECHNICAL FIELD

[0001] The present application relates to a black quartz glass and a manufacturing method thereof, and a black quartz glass product. More specifically, the present application relates to a black quartz glass which can be used in a quartz glass unit for optical analysis, a mirror for a projector, a connector for an optical fiber, a light shielding member for a semiconductor manufacturing device or an infrared ray heating device, an infrared ray heat absorbing / accumulating member, and the like, and a manufacturing method for efficiently obtaining the same.

[0002] Cross Reference to Related Applications

[0003] This application claims priority to Japanese Patent Application No. 2020-169478 filed on October 7, 2020, and Japanese Patent Application No. 2021-146784 filed on September 9, 2021, the entire disclosures of which are hereby incorporated by reference in its entirety. BACKGROUND

[0004] Quartz glass is used for various purposes such as lighting devices, optical device parts, semiconductor industry parts, physicochemical devices, and the like, by effectively utilizing its good light transmittance from the ultraviolet region to the infrared region, low thermal expansion, and resistance to chemicals. Among them, a black glass in which a trace amount of a transition metal oxide is added to quartz glass is used for a site where local light shielding is required, and is utilized in optical device parts such as a quartz glass unit for optical analysis. However, in recent years, with the development of miniaturization / thin-type of parts, the conventional black glass has caused a case where light shielding is insufficient, and a black quartz glass with higher light shielding is required.

[0005] In addition, in the projector use, in order to prevent adverse effects on the optical system inside the projector accompanying the high brightness of the bulb for making the projected image brighter, a black quartz glass capable of efficiently shielding the light leakage from the mirror is required.

[0006] In the optical fiber use, in the connector for connecting optical fibers, it is necessary to prevent diffuse reflection caused by light leakage, but with the increase in the optical transmission density, a black quartz glass with higher light shielding is required.

[0007] Further, quartz glass also has features such as high heat resistance, high purity in chemistry, and the like, and is also used in jigs for semiconductor manufacturing and the like. However, in recent years, in the heat treatment process of the semiconductor manufacturing process, heating loss becomes a problem, and in the heating process using infrared light, a shielding member for shielding the infrared light irradiation other than the heating object, an infrared ray heat absorbing / accumulating member for efficiently heating the heating object are required. Based on this, development of a black quartz glass which effectively shields infrared rays, has excellent infrared ray heat absorbing / accumulating properties, and can manufacture a large member, and does not contain metal impurities which cause process contamination, is required.

[0008] In the past, as a black quartz glass in which silica is a main component, a black quartz glass described below has been known.

[0009] For example, in Patent Literature 1, a manufacturing method of a black quartz glass is proposed in which quartz glass powder and niobium pentachloride are mixed, and after the niobium pentachloride is converted into niobium pentoxide, it is heated to 1800°C or higher to be reduced and melted, thereby to be realized.

[0010] In Patent Literature 2, it is proposed that a volatile organosilicon compound capable of becoming a carbon source is subjected to a gas phase reaction with a silica porous glass, and after that, a heating and firing at a temperature of 1200°C or higher and 2000°C or lower is performed, thereby to manufacture a black quartz glass containing carbon derived from the organosilicon compound.

[0011] In Patent Literature 3, it is proposed that after a fused silica powder obtained by powderizing a fused quartz glass and a silicon-containing powder are wet-mixed, a molding is formed by a casting method and dried, and the obtained molding is heated at a sintering temperature of less than the melting temperature of silicon, 1350°C to 1435°C, thereby to manufacture a black quartz glass as a composite material having a matrix of fused silica in which a region in which Si is embedded in an elemental form.

[0012] In Patent Literature 4, a colored glass sintered body in which carbon as coloring particles at a volume ratio of 0.1% to 30% is dispersed in a matrix of a glass sintered body is proposed.

[0013] In Patent Literature 5, a TiO2-containing silica glass is disclosed. As a manufacturing method of the silica glass, a method is proposed in which a porous TiO2-SiO2 glass body obtained by accumulating soot obtained by flame hydrolysis of a gasifiable Si precursor and a Ti precursor is contained with fluorine, and finally, a glass transition temperature is reached, thereby to obtain a black quartz glass.

[0014] In Patent Literature 6, a colored alumina sintered body is disclosed. The sintered body is obtained by mixing Al2O3, TiO2, Cr2O3, and CaO, SiO2, MgO as a sintering aid component and firing in a reducing atmosphere.

[0015] Patent Literature 1: Japanese Patent Application Publication No. 2014-94864

[0016] Patent Literature 2: Japanese Patent Application Publication No. 2013-1628

[0017] Patent Literature 3: Japanese Patent Application Publication No. 2020-73440

[0018] Patent Literature 4: Japanese Patent Application Publication No. 2003-146676

[0019] Patent Document 5: Japanese Patent Application Laid-Open (JP-A) No. 2005-194118

[0020] Patent Document 6: Japanese Patent Application Laid-Open (JP-A) No. 2000-327405

[0021] The entire disclosures of Patent Documents 1 to 6 are incorporated herein by reference as a disclosure. SUMMARY

[0022] PROBLEMS TO BE SOLVED BY THE INVENTION

[0023] However, the black quartz glass described in Patent Document 1 has a problem in that the uniformity of color is insufficient when it is upsized, and there is a problem in productivity. In addition, contamination can occur in the process of using the contained niobium compound, so there are difficulties in application to the semiconductor manufacturing field.

[0024] The black quartz glass described in Patent Document 2 also has a problem in the uniformity of color, and it is difficult to upsize.

[0025] In addition, the contained carbon is generated in the process of using it as a particle, and contamination can occur, so there are difficulties in application to the semiconductor manufacturing field.

[0026] The black quartz glass described in Patent Document 3 also has a problem in that the uniformity of color is insufficient when it is upsized. Moreover, there is a problem in upsize due to the limitation of casting molding. In addition, the operation of casting molding / drying is complicated, and a long time is required for production, so there is a problem in productivity.

[0027] The black quartz glass described in Patent Document 4 also has a problem in that the uniformity of color is insufficient when it is upsized, and in the case of upsizing, the risk of breakage at the time of sintering of the molded body becomes large, so there is a problem in that a large black quartz glass cannot be obtained. In addition to this, carbon is generated in the process of using it as a particle, and contamination can occur, so there are difficulties in application to the semiconductor manufacturing field.

[0028] The TiO2-containing silica glass described in Patent Document 5 requires a process of making soot accumulate, so the production is complicated and requires a complicated operation, and there is a problem in productivity. Moreover, it is also difficult to upsize, and even if it can be upsized, there is a problem in that the uniformity of color is insufficient.

[0029] The colored alumina sintered body described in Patent Document 6 has a grain boundary, so there are problems in that the yield of the product is reduced due to particle peeling at the time of thinning in the process of use, and in addition, as a part of the raw material for production, it is not easy to obtain a high-purity powder, and it is necessary to use Mg and Ca, which are elements to be avoided in the semiconductor manufacturing process, so there is also a problem in that it is difficult to apply to the semiconductor manufacturing process.

[0030] The black quartz glass and the like obtained by the above conventional method have problems of color uniformity and contamination when large-sized, and the manufacturing method of the black quartz glass is difficult to be large-sized, and there are problems in productivity. On the other hand, the colored alumina sinter has problems of reduction of yield due to grain boundaries, difficulty in obtaining a part of raw materials, and necessity of using an avoiding element in a semiconductor manufacturing process.

[0031] The present application has an object to provide a black quartz glass having excellent light shielding property, not causing contamination in a process of use, having sufficient color uniformity when large-sized, and capable of producing a large ingot.

[0032] Another object of the present application is to provide a method of manufacturing the black quartz glass solving the above problems with excellent productivity even for a large ingot.

[0033] Still another object of the present application is to provide an optical member such as a light splitting unit, a light shielding member for a semiconductor manufacturing apparatus or an infrared heating apparatus, and a black quartz glass product.

[0034] Technical solution for solving the problem

[0035] The present inventors have made intensive studies to solve the above problems, and as a result, have found that a quartz glass having SiO2 as a main component and containing TiO2 and Al2O3 in a prescribed range is a black quartz glass having excellent light shielding property, and the black quartz glass can be obtained in a state of being uniform and having no cracks and bubbles in the glass by mixing SiO2 powder, TiO2 powder, and Al2O3 powder in a prescribed composition and melting them, thereby completing the present application.

[0036] The present application is as follows.

[0037] [1] A black quartz glass comprising a composition of 63 to 65 mass% of SiO2, 18 to 24 mass% of TiO2, and 12 to 17 mass% of Al2O3, and in the composition, the total of SiO2, TiO2, and Al2O3 is 100 mass%.

[0038] [2] The black quartz glass according to [1],

[0039] SCE reflectance at a wavelength of 350 to 750 nm is 8% or less.

[0040] [3] The black quartz glass according to [1] or [2],

[0041] L * a * b* Luminance L of the display system * a is 20 or less, chromaticity b * is 2 or less in absolute value and b * is 9 or less in absolute value.

[0042] [4] The black quartz glass according to any one of [1] to [3],

[0043] The content of metal impurities other than Si, Ti, and Al is 1 ppm or less, respectively.

[0044] [5] The black quartz glass according to any one of [1] to [4],

[0045] The density is 2.3 g / cm 3 or more and 2.8 g / cm 3 or less.

[0046] [6] The black quartz glass according to any one of [1] to [5],

[0047] The black quartz glass has a corrosion rate of 1 / 5 or less compared to a corrosion rate of a fused quartz glass obtained by the same corrosion exposure test,

[0048] The corrosion exposure test: (1) a glass sample of 20 mm x 20 mm x 2 mm thick is prepared, an optical mirror surface is formed on the surface thereof, and a 7 mm x 7 mm portion is masked after that; (2) using a reactive ion etching device, while flowing CF4 gas, O2 gas, and Ar simultaneously, the pressure in the device is made 14 Pa, and the entire surface of the glass to which the mask is applied is etched at 200 W for 4 hours; (3) the mask is removed from the surface of the glass, and the height difference between the masked portion and the non-masked portion subjected to corrosion is measured; (4) the corrosion rate is calculated from the height difference / etching time.

[0049] [7] The black quartz glass according to any one of [1] to [6],

[0050] The thermal expansion rate in the range of 30°C to 600°C is 20 x 10 -7 / °C or more and 30 x 10 -7 / °C or less.

[0051] [8] The black quartz glass according to any one of [1] to [7],

[0052] The light transmittance at a wavelength of 200 nm to 3000 nm is 0.1% or less at a thickness of 1 mm.

[0053] [9] A method of manufacturing a black quartz glass, comprising:

[0054] The SiO2 powder 63 to 65 mass%, TiO2 powder 18 to 24 mass%, and Al2O3 powder 12 to 17 mass% are mixed, the mixed powder is filled in a mold, and then, in an oxygen-free atmosphere, is melted at a maximum temperature of 1700 to 1900°C, and is cooled to room temperature to obtain the black quartz glass described in any one of [1] to [8].

[0055]

[10] The method for producing a black quartz glass according to [9],

[0056] The oxygen-free atmosphere is a reduced pressure of 100 Pa or less, a N2 atmosphere, an Ar atmosphere, a He atmosphere, or a combination thereof.

[0057]

[11] The method for producing a black quartz glass according to [9] or

[10] ,

[0058] The shape of the mold filled with the mixed powder is a similar shape to the machined shape, and the volume is 1.01 or more of the machined shape.

[0059]

[12] An article comprising a black quartz glass member using the black quartz glass described in any one of [1] to [8].

[0060]

[13] The article according to

[12] ,

[0061] The black quartz glass member is an optical component, a light shielding member, or an infrared heat absorbing / accumulating member.

[0062]

[14] The article according to

[13] ,

[0063] The optical component is a light splitting unit, a mirror of a projector, or a connector of an optical fiber, and the light shielding member is a light shielding member of a semiconductor manufacturing device or an infrared heating device.

[0064] Effects of the Invention

[0065] According to the present application, a black quartz glass which is uniform and has no cracks or bubbles in the glass and has high light shielding properties can be provided. The black quartz glass does not lose the good workability and low dust emission properties of transparent quartz glass, is uniform, and has excellent light shielding properties. Thus, it can be suitably used in a quartz glass unit for optical analysis, a mirror of a projector, a connector of an optical fiber, a light shielding member of a semiconductor manufacturing device or an infrared heating device, an infrared heat absorbing / accumulating member, and the like. In addition, according to the production method of the present application, a black quartz glass can be easily produced with high purity and without losing the good workability and low dust emission properties of transparent quartz glass. DETAILED DESCRIPTION

[0066] <Black Quartz Glass>

[0067] The black quartz glass of the present application is described. The black quartz glass of the present application has a composition in which SiO2 is 63 mass% to 65 mass% and is a main component, TiO2 is 18 mass% to 24 mass%, and Al2O3 is 12 mass% to 17 mass%, and the total of SiO2, TiO2, and Al2O3 is 100 mass%. By being in this composition range, a black quartz glass can be particularly obtained uniformly and without cracks and bubbles. If the composition range is deviated, color unevenness, inclusion of bubbles, and the like occur, and a uniform glass phase is not obtained, and the good workability and low dust emission of a transparent quartz glass are lost. The composition range of the black quartz glass of the present application is preferably a range in which SiO2 is 63.5 mass% to 65.0 mass%, TiO2 is 18.5 mass% to 23.5 mass%, and Al2O3 is 12.5 mass% to 17.0 mass%.

[0068] The black quartz glass of the present application preferably has an SCE reflectance of 8% or less at a wavelength of 350 nm to 750 nm. The SCE reflectance at a wavelength of 350 nm to 750 nm is measured in accordance with JIS Z 8722. By making the SCE reflectance 8% or less, excellent light shielding properties are exhibited. From the viewpoint of excellent light shielding properties, the SCE reflectance is preferably low, and is preferably 7% or less, and more preferably 5% or less. The lower limit of the SCE reflectance is not particularly limited, but can be 1%.

[0069] The black quartz glass of the present application preferably has an SCE reflectance of 8% or less at a wavelength of 350 nm to 750 nm. The SCE reflectance at a wavelength of 350 nm to 750 nm is measured in accordance with JIS Z 8722. By making the SCE reflectance 8% or less, excellent light shielding properties are exhibited. From the viewpoint of excellent light shielding properties, the SCE reflectance is preferably low, and is preferably 7% or less, and more preferably 5% or less. The lower limit of the SCE reflectance is not particularly limited, but can be 1%. * a * b * The lightness L of the display system * is preferably 20 or less, the absolute value of the chroma a * is preferably 2 or less, and the absolute value of the chroma b * is preferably 9 or less. By making the lightness L * 20 or less, not only color unevenness does not occur, but also a sufficient black color in which transmission of light, stray light, and scattering do not occur can be exhibited. In addition, by making the absolute value of the chroma a * 2 or less and the absolute value of the chroma b * 9 or less, the color tone of the glass body becomes darker, and a black quartz glass having a low SCE reflectance is obtained. The lightness L * is preferably 18 or less, the absolute value of the chroma a * is preferably 1.8 or less, and the absolute value of the chroma b * is preferably 8.5 or less, which makes the color tone darker and is preferable.

[0070] The black quartz glass of the present application preferably has a content of metal impurities other than Si, Ti, and Al of 1 ppm or less. By having a content of metal impurities of 1 ppm or less, occurrence of process contamination in the production of semiconductors and the like can be suppressed. In addition, adverse effects on precision such as generation of fluorescence in the field of optical analysis and the like can be suppressed. The content of metal impurities other than Si can be analyzed, for example, using atomic absorption spectrometry and the like.

[0071] The black quartz glass of the present application preferably has a density of 2.3 g / cm 3 or more and 2.8 g / cm 3 or less. The density is almost the same as the theoretical density of a molten glassified TiO2and Al2O3in a transparent quartz glass. The density is preferably 2.4 g / cm 3 or more and 2.7 g / cm 3 or less.

[0072] The black quartz glass of the present application has an etching rate of 1 / 5 or less of the etching rate of a fused quartz glass in an etching environment in which a reactive ion etching device (200 W) is used while flowing CF4gas, O2gas, and Ar. The fused quartz glass used as a control is produced by heating and melting natural quartz powder using a hydrogen-oxygen burner. Such a black quartz glass having excellent etching resistance can be used as a component for semiconductor production, a component for liquid crystal production, a component for MEMS production, and the like, and can greatly reduce particle generation and slip even in an etching environment.

[0073] The black quartz glass of the present application has a thermal expansion rate of 20 x 10 -7 / °C or more and 25 x 10 -7 / °C or less. The thermal expansion coefficient of alumina ceramics is 80 x 10 -7 / °C, and the thermal expansion coefficient of titanium oxide ceramics is 70 x 10 -7 / °C to 100 x 10 -7 / °C. The expansion rate is about 1 / 3 to 1 / 4 as small as these. Thus, it can be suitably used in an environment requiring dimensional precision at high temperatures, such as the optical system of a projector.

[0074] The black quartz glass of the present application preferably has a light transmittance of 0.1% or less at a wavelength of 200 nm to 3000 nm at a thickness of 1 mm. The light transmittance at a wavelength of 200 nm to 3000 nm is measured using a spectrophotometer. By having a light transmittance of 0.1% or less, excellent light shielding properties are exhibited. From the viewpoint of excellent light shielding properties, the light transmittance is preferably low, and is preferably 0.07% or less, and more preferably 0.05% or less. The lower limit of the light transmittance is not particularly limited, but can be 0.01%.

[0075] Method for manufacturing black quartz glass

[0076] A method for manufacturing black quartz glass according to the present application will be described.

[0077] The method for manufacturing black quartz glass according to the present application includes mixing SiO2 powder 63 to 65 mass%, TiO2 powder 18 to 24 mass%, and Al2O3 powder 12 to 17 mass%, filling the mixed powder in a mold, melting the mixed powder at a maximum temperature of 1700 to 1900°C in an oxygen-free atmosphere, and cooling to room temperature to obtain the black quartz glass according to the present application.

[0078] From the viewpoint of obtaining black quartz glass having a small amount of impurities, the SiO2 powder, the TiO2 powder, and the Al2O3 powder are preferably high-purity powders. The high-purity powders of the SiO2 powder, the TiO2 powder, and the Al2O3 powder can be easily obtained as commercially available products. The high-purity powders preferably have a content of metal impurities other than Si, Ti, and Al of 1 ppm or less each. The particle diameter, shape, and the like of the raw material powders are not particularly limited, but the particle diameter, shape, and the like of each raw material are preferably appropriately selected so that the three components are uniformly mixed and dispersed. In addition, from the viewpoint of easily melting the mixed powder, the particle diameter is preferably small, and for example, the average particle diameter can be in the range of 0.1 μm to 300 μm.

[0079] The raw materials are mixed in a dry powder state to obtain the raw material powder. The proportions of the SiO2 powder, the TiO2 powder, and the Al2O3 powder are selected from the ranges of 63 to 65 mass%, 18 to 24 mass%, and 12 to 17 mass%, respectively, depending on the composition of the black quartz glass. Generally, a melt of SiO2, TiO2, and Al2O3 generates a large amount of phase separation, cracks, and bubbles in the visual grade, and the obtained glass is not practical. However, through the research of the present inventors, it was found that, surprisingly, within the composition range of the present application, a quartz glass that is uniform and has no phase separation, cracks, or bubbles in the glass and is black can be obtained. Furthermore, the obtained quartz glass is a black quartz glass that does not lose good processability, low dusting, and high shielding properties. The mixing of the raw material powder can be performed using, for example, a general mixing device such as a stirring-type mixer, a ball mill, a swing mixer, a cross mixer, a V-type mixer, and the like.

[0080] The raw material powder obtained by the mixing is filled in a mold of a desired shape. The shape of the mold is not particularly limited, but from the viewpoint of approximating the shape of the product after machining and being able to efficiently obtain the product, a similar shape to the shape after machining and a volume of 1.01 times or more are ideal. The mold is not particularly limited, and for example, can be a carbon mold.

[0081] The melting of the raw material powder is performed by heating the powder raw material filled in a mold to a maximum temperature of 1700 to 1900°C, preferably 1750 to 1850°C, in an oxygen-free atmosphere. If the maximum temperature is lower than 1700°C, the vitrification is not sufficient. If it exceeds 1900°C, SiO2begins to vaporize, which is not preferable. The oxygen-free atmosphere means, for example, a reduced pressure of 100 Pa or less, an N2atmosphere, an Ar atmosphere, a He atmosphere, or a combination thereof. For example, it can be an N2, Ar, or He atmosphere after the reduced pressure is reduced to 100 Pa or less, or, after further reduced pressure, a reduced pressure N2, Ar, or He atmosphere. By melting and vitrifying by heating in an oxygen-free atmosphere, a black quartz glass is obtained. Even if it is melted and vitrified by heating in an oxygen-containing atmosphere, it is difficult to blacken, or a blackened quartz glass cannot be obtained. The heating and melting time is not particularly limited, but for example, it is 0.1 to 10 hours. However, it is not intended to be limited to this range. By cooling to room temperature after melting and being removed from the mold, an ingot of the black quartz glass of the present application is obtained.

[0082] By processing the ingot of the black quartz glass obtained by the above process using a processing machine such as a band saw, a wire saw, a core drill, etc. used in the manufacture of quartz parts, a product of the black quartz glass can be obtained.

[0083] The black quartz glass thus obtained has no color unevenness, exhibits a sufficient black color system color in which transmission of light, stray light, and scattering do not occur, and is useful in the entire optical field.

[0084] <Products containing black quartz glass parts>

[0085] The present application includes products containing a black quartz glass part using the above black quartz glass of the present application. The black quartz glass part can be, for example, an optical component, a light shielding component, or an infrared heat absorbing / accumulating component. The optical component is, for example, a light splitting unit, a mirror of a projector, or a connector of an optical fiber, and the light shielding component is, for example, a light shielding component of a semiconductor manufacturing device or an infrared heating device. However, it is not intended to be limited to these components.

[0086] The black quartz glass of the present application does not contain elements to be avoided in the semiconductor manufacturing process, and is suitable for a component of a heat treatment device used in semiconductor manufacturing. For example, in a wafer heat treatment device, by constituting a portion other than the surface through which infrared rays for heating are transmitted using the black quartz glass of the present application, the heat radiated to the outside of the furnace can be efficiently shielded, and energy efficiency can be improved and the temperature distribution in the furnace can be uniformized.

[0087] Example

[0088] Hereinafter, the present application will be specifically described using examples, but the present application is not limited to the examples.

[0089] The sample properties were measured as follows.

[0090] (1) The density of the sample was measured using the Archimedes method.

[0091] (2) The SCE reflectance was measured by processing the sample to a thickness of 7 mm, using a spectrophotometer according to JIS Z 8722. The highest value was recorded in the wavelength range of 360 nm to 740 nm.

[0092] (3) L * a * b * The lightness L of the display system * and the chromaticity a * , b * were measured using a spectrophotometer according to JIS Z 8722.

[0093] (4) The thermal expansion rate was measured by processing the sample to 3 x 4 x 20 mm L, and measuring using the thermal mechanical analysis method (TMA method) under conditions of 30°C to 600°C.

[0094] (5) The light transmittance was measured by processing the sample to a thickness of 1 mm, and measuring using a spectrophotometer in the range of 200 nm to 3000 nm.

[0095] (6) Corrosion exposure test for corrosion rate measurement:

[0096] (1) A 20 mm x 20 mm x 2 mm thick glass sample was prepared, an optical mirror surface was formed on the surface thereof, and a 7 mm x 7 mm portion was masked. (2) Using a reactive ion etching device, while flowing CF4 gas, O2 gas and Ar gas simultaneously, the pressure in the device was made 14 Pa, and the entire surface of the glass to which the mask was applied was etched for 4 hours at 200 W. (3) The mask was removed from the surface of the glass, and the height difference between the masked portion and the non-masked portion subjected to etching was measured. (4) The corrosion rate was calculated from the height difference / etching time. As a control, a fused quartz glass was produced by heating and melting natural crystal powder using a hydrogen-oxygen burner.

[0097] (Example 1)

[0098] SiO2 powder with a content of less than 1 ppm of metallic impurities other than Si, TiO2 powder with a content of less than 1 ppm of metallic impurities other than Ti, and Al2O3 powder with a content of less than 1 ppm of metallic impurities other than Al were prepared. 64.5% by mass of SiO2 powder, 18.6% by mass of TiO2 powder, and 16.9% by mass of Al2O3 powder were mixed using a ball mill without solvent. The obtained raw material powder was filled into a mold and heated to a maximum temperature of 1800°C for 20 minutes in a nitrogen atmosphere to melt it. After melting, it was cooled to room temperature to obtain black quartz glass. The physical properties of the obtained black quartz glass are as follows: density is 2.6 g / cm³. 3 The SCE reflectance is below 3.3%, the transmittance is below 0.05% in the range of 200nm to 3000nm, and the coefficient of thermal expansion is 25×10⁻⁶. -7 / ℃, L * a * b * The brightness of the display system L * It is 8.9, chromaticity a * For 1.1, b * The corrosion rate was -6.8. The corrosion rate in the corrosion exposure test was 9.55 nm / min, which is 1 / 5.4 compared to the 51.79 nm / min of fused silica glass. The obtained black silica glass exhibits a fully black color with no light transmission, stray light, or scattering. Visual inspection confirmed the absence of bubbles, cracks, and color unevenness, and it also possesses excellent aesthetic appeal.

[0099] (Example 2)

[0100] Using the same SiO2, TiO2, and Al2O3 powders as in Example 1, 63.9% by mass of SiO2 powder, 23.2% by mass of TiO2 powder, and 12.9% by mass of Al2O3 powder were mixed in a ball mill without solvent. The resulting powder was filled into a mold and melted by heating at a maximum temperature of 1800°C for 20 minutes in a nitrogen atmosphere. After melting, it was cooled to room temperature to obtain black quartz glass. The physical properties of the obtained black quartz glass are as follows: density is 2.6 g / cm³. 3 The SCE reflectance is below 4.1%, the transmittance is below 0.06% in the range of 200nm to 3000nm, and the coefficient of thermal expansion is 28×10⁻⁶. -7 / ℃, L * a * b * The brightness of the display system L * It is 13.1, chromaticity a * It is 0.6, b *was -7.1. The corrosion rate in the corrosion exposure test was 9.92 nm / min, which was 1 / 5.2 compared to 51.79 nm / min of the fused quartz glass. The obtained black quartz glass exhibited a sufficient black color that did not transmit light, did not scatter light, and did not have stray light, and no bubbles, cracks, color unevenness were visually confirmed, and was excellent in appearance.

[0101] (Comparative Example 1)

[0102] The same Si02 powder, Ti02 powder, and Al203 powder as in Example 1 were used, and the Si02 powder 85.4 mass%, Ti02 powder 11.2 mass%, and Al203 powder 3.4 mass% were mixed using a ball mill without using a solvent. The obtained raw material powder was filled in a mold, and was melted by heating at a maximum temperature of 1800°C for 20 minutes in a nitrogen atmosphere. After melting, it was cooled to room temperature. Color unevenness, bubbles, and cracks were visually confirmed to have occurred in the obtained melt.

[0103] (Comparative Example 2)

[0104] The same Si02 powder, Ti02 powder, and Al203 powder as in Example 1 were used, and the Si02 powder 51.0 mass%, Ti02 powder 24.0 mass%, and Al203 powder 25.0 mass% were mixed using a ball mill without using a solvent. The obtained raw material powder was filled in a mold, and was melted by heating at a maximum temperature of 1800°C for 20 minutes in a nitrogen atmosphere. After melting, it was cooled to room temperature. Color unevenness, bubbles, and cracks were visually confirmed to have occurred in the obtained melt.

[0105] [Table 1]

[0106]

[0107] Industrial Applicability

[0108] The present application is useful in the field relating to the use and production of black quartz glass. The production method of black quartz glass according to the present application can economically and efficiently produce large-sized black quartz glass that does not lose the good workability, low dust emission, and uniformity and excellent light shielding property of transparent quartz glass. The black quartz glass of the present application can be suitably used for a quartz glass cell for optical analysis, a mirror of a projector, an optical part such as a connector of an optical fiber, a light shielding member of a semiconductor manufacturing device or an infrared ray heating device, and an infrared ray heat absorbing / accumulating member.

Claims

1. A black quartz glass, which comprises a composition of Si02 63 to 65 mass%, Ti02 18 to 24 mass%, and Al203 12 to 17 mass%, the total of Si02, Ti02, and Al203 in the composition being 100 mass%, the black quartz glass being obtained by melting raw materials at a maximum temperature of 1700 to 1900°C under an oxygen-free atmosphere, and cooling to room temperature, wherein The L * a * b * The luminance L * of the display system is 20 or less, the absolute value of the chromaticity a * is 2 or less, and the absolute value of the chromaticity b * is 9 or less.

2. The black quartz glass according to claim 1, SCE reflectance at a wavelength of 350 to 750 nm is 8% or less.

3. The black quartz glass according to claim 1 or 2, the content of metal impurities other than Si, Ti, and Al is 1 ppm or less each.

4. The black quartz glass according to claim 1 or 2, Density 2.3 g / cm 3 Above and 2.8 g / cm 3 Below.

5. The black quartz glass according to claim 1 or 2, the black quartz glass, an etching rate obtained by the following etching exposure test is 1 / 5 or less compared to an etching rate of a fused quartz glass obtained by the same etching exposure test, the etching exposure test: (1) a glass sample of 20 mm x 20 mm x 2 mm thickness is prepared, an optical mirror surface is formed on the surface thereof, and a 7 mm x 7 mm portion is masked after that; (2) using a reactive ion etching device, while flowing CF4 gas, O2 gas, and Ar gas simultaneously, the pressure in the device is made 14 Pa, and the entire surface of the glass to which the mask is applied is etched at 200 W for 4 hours; (3) the mask is removed from the surface of the glass, and the height difference between the masked portion and the unmasked portion subjected to etching is measured; (4) the etching rate is calculated from the height difference / etching time.

6. The black quartz glass according to claim 1 or 2, 30 to 600°C, is 20 x 10 -7 / °C or more and 30 x 10 -7 / °C or less.

7. The black quartz glass according to claim 1 or 2, the light transmittance at a wavelength of 200 to 3000 nm is 0.1% or less at a thickness of 1 mm.

8. A manufacturing method of a black quartz glass, comprising: mixing Si02 powder 63 to 65 mass%, Ti02 powder 18 to 24 mass%, and Al203 powder 12 to 17 mass%, filling the mixed powder in a mold, melting the mixed powder in the mold at a maximum temperature of 1700 to 1900°C under an oxygen-free atmosphere, and cooling to room temperature to obtain the black quartz glass according to any one of claims 1 to 7.

9. The manufacturing method of a black quartz glass according to claim 8, the oxygen-free atmosphere is a reduced pressure of 100 Pa or less, a N2 atmosphere, an Ar atmosphere, a He atmosphere, or a combination thereof.

10. The manufacturing method of a black quartz glass according to claim 8 or 9, the shape of the mold filled with the mixed powder is a similar shape to a machined shape, and the volume is 1.01 or more of the machined shape.

11. An article comprising a black quartz glass member using the black quartz glass according to any one of claims 1 to 7.

12. The article according to claim 11, the black quartz glass member is an optical component, a light shielding component, or an infrared heat absorbing / accumulating component.

13. The article of claim 12, The optical member is a light splitting unit, a mirror of a projector, or a connector of an optical fiber, and the light shielding member is a light shielding member of a semiconductor manufacturing apparatus or an infrared heating apparatus.

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