Black quartz glass, method for producing same, and member and product using same

Abstract

In a cross section of the glass structure of this black quartz glass, the number of pores having a pore diameter of 30 μm or more is 5 / mm2 or less. The method for producing the black quartz glass includes sintering a silica powder to which Si powder and SiO powder or only Si powder have been added in a predetermined ratio. The silica powder contains 10-40 mass% of fumed silica and 10-40 mass% of a first spherical silica having a predetermined D50, with the balance being a second spherical silica having a predetermined D50 larger than the D50 of the first spherical silica, based on the total mass. The present invention can provide a black quartz glass having an excellent light-blocking property, excellent mechanical strength, heat resistance, and thermal shock resistance. The black quartz glass poses no risk of causing contamination in processes in which black quartz glass is used, can be made larger, and has sufficient color uniformity even when made larger. In addition, a method for producing the black quartz glass and a member and a product that use the black quartz glass are provided.

Description

Black quartz glass, its manufacturing method, and components and products that use it

[0001] The present invention relates to black quartz glass, a method for producing the same, and components and products using the same. More specifically, the present invention relates to black quartz glass that can be suitably used as a material for components (e.g., optical cells, light-shielding members, infrared-absorbing members, and heat-storing members) for various products (e.g., optical analysis equipment, semiconductor manufacturing equipment, and infrared heating equipment), and further relates to a method for efficiently producing the black quartz glass and products that include the black quartz glass as a component.

[0002] Quartz glass has excellent optical transparency from the ultraviolet to the infrared range, heat resistance, chemical resistance, and a low coefficient of thermal expansion. Taking advantage of these advantages, it is used in a variety of applications, including lighting equipment, optical equipment, semiconductor manufacturing equipment, and laboratory equipment.

[0003] In addition, black quartz glass is also known, which is obtained by adding, for example, a trace amount of transition metal oxide to the above-mentioned transparent quartz glass. Like ordinary transparent quartz glass, black quartz glass has excellent heat resistance, chemical resistance, and a low thermal expansion coefficient, while also offering light-blocking properties. Taking advantage of its light-blocking properties, black quartz glass is used in areas of equipment and devices where localized light blocking is required. Black quartz glass can be bonded to transparent quartz glass by bonding methods such as thermocompression bonding, and is used as a component for various equipment and devices.

[0004] Furthermore, black quartz glass has excellent infrared absorption and heat storage properties, as well as high purity, and these advantages have led to its use as an infrared absorption or heat storage material in semiconductor manufacturing. Black quartz glass is placed in a position that shields items other than the object being heated from infrared radiation during the infrared heat treatment process in the semiconductor manufacturing process, absorbing the infrared radiation and storing the heat. This reduces contamination inside the equipment while also reducing heat loss caused by items other than the object being heated absorbing the infrared radiation and then transmitting the heat to the outside.

[0005] In recent years, as components have become increasingly miniaturized and thinner, the light-shielding properties of conventional black quartz glass may be insufficient, and black quartz glass with even higher light-shielding properties is in demand.

[0006] Black quartz glass is produced, for example, by the following method.

[0007] Patent Document 1 discloses a method for producing black quartz glass, in which quartz glass powder is mixed with niobium pentachloride, the niobium pentachloride is converted to niobium pentoxide, and then the mixture is heated to 1800°C or higher for reduction melting to obtain black quartz glass.

[0008] Patent Document 2 discloses a method for producing black quartz glass, in which a volatile organosilicon compound is reacted with porous silica glass in a gas phase, and then the mixture is heated and fired at a temperature of 1200°C or higher and 2000°C or lower, to obtain black quartz glass containing carbon derived from the organosilicon compound.

[0009] Patent Document 3 discloses a method for producing black quartz glass, in which fused silica powder, which is obtained by powdering fused quartz glass, is wet-mixed with a silicon-containing powder, the mixture is molded by a casting method, dried, and the resulting molded body is heated at a sintering temperature below the melting temperature of silicon, thereby obtaining black quartz glass in which elemental Si regions are embedded in a fused silica matrix.

[0010] Additionally, Patent Document 4 discloses a colored sintered glass body in which carbon is dispersed as colored particles in a volume ratio of 0.1% to 30% in the matrix of the sintered glass body.

[0011] JP 2014-94864 A (claims and others) JP 2013-1628 A (claims and others) JP 2020-73440 A (claims and others) JP 2003-146676 A (claims and others)

[0012] However, the black quartz glass described in Patent Document 1 may not have sufficient color uniformity when enlarged (e.g., in the production of ingots). Color non-uniformity results in variations in light-shielding properties, which can lead to insufficient light-shielding properties. Furthermore, the production of black quartz glass requires temperatures of 1800°C or higher, which requires the use of high-quality furnace and heater materials, and also requires a great deal of energy for heating, resulting in productivity issues. Additionally, the niobium compounds contained in the black quartz glass may cause contamination in processes using the black quartz glass, making the black quartz glass described in Patent Document 1 unusable in semiconductor manufacturing processes.

[0013] The black quartz glass described in Patent Document 2 may also lack sufficient color uniformity when enlarged. Furthermore, a non-oxidizing atmosphere is required to manufacture the black quartz glass, which complicates the furnace structure and makes the operation cumbersome, making it difficult to improve productivity. Due to such a complex furnace structure, it is difficult to flexibly accommodate larger sizes of black quartz glass. Furthermore, the carbon contained in the black quartz glass may cause contamination in processes in which the black quartz glass is used, making the black quartz glass described in Patent Document 2 unusable in semiconductor manufacturing processes.

[0014] The black quartz glass described in Patent Document 3 also sometimes lacks color uniformity when made into a large size, and due to the presence of micropores within the structure, it has insufficient strength, heat resistance, and thermal shock resistance during mechanical processing. Furthermore, limitations on slip casting make it difficult to make large-sized black quartz glass. In addition, the slip casting and drying processes are complicated, requiring a long manufacturing time.

[0015] The black quartz glass described in Patent Document 4 may also lack sufficient color uniformity when enlarged. Furthermore, when the black quartz glass described in Patent Document 4 is enlarged, there is a high risk of breakage when sintering the molded body. In addition, the carbon contained in the black quartz glass may cause contamination in the process in which the black quartz glass is used, so the black quartz glass described in Patent Document 4 cannot be used in the semiconductor manufacturing process.

[0016] The problem to be solved by the present invention is to provide black quartz glass that has excellent light-shielding properties as well as excellent mechanical strength, heat resistance, and thermal shock resistance, that does not cause contamination in processes in which the black quartz glass is used, that can be made large, and that maintains sufficient color uniformity even when made large.

[0017] Another object of the present invention is to provide a method for producing black quartz glass that enables the black quartz glass of the present invention to be produced with excellent productivity and in large sizes.

[0018] A further object of the present invention is to provide a black quartz glass member manufactured from the black quartz glass of the present invention and a product containing the same.

[0019] As a result of intensive research to solve the above problems, the inventors have found that by mixing a silica powder containing fumed silica and a plurality of spherical silica particles having small average particle sizes and different from each other with Si powder and SiO powder or Si powder alone in specific ratios and sintering this mixed powder, it is possible to obtain black quartz glass having excellent light-shielding properties as well as excellent mechanical strength, heat resistance, and thermal shock resistance. Furthermore, it was found that this black quartz glass does not cause contamination in processes in which it is used, can be made into a large size, and maintains sufficient color uniformity even when made into a large size, and the inventors have completed the present invention.

[0020] The present invention is as follows: [1] A black quartz glass containing 0.5 to 10 parts by mass of Si and 0 to 5 parts by mass of SiO per 100 parts by mass of silica, wherein the glass structure is substantially free of pores, and the number of pores with a diameter of 30 μm or more is 5 / mm in a microscopic image of a cross section of the glass structure. ２ [2] The black quartz glass according to [1], which has a water absorption of 0.1% or less. [3] The black quartz glass according to [1] or [2], which has a density whose difference in density compared to the theoretical density is 1% or less in absolute value. [4] L ＊ a ＊ b＊ In the color system, the lightness L is 30 or less ＊ , saturation a below 3.5 ＊ and saturation b less than 4 ＊ [5] The black quartz glass according to any one of [1] to [4], wherein the contents of metal impurities in the black quartz glass are each 1 ppm or less. [6] The black quartz glass according to any one of [1] to [5], which satisfies one or more of the following (a) to (i): (a) the black quartz glass has a viscosity of 2.19 to 2.30 g / cm ３ (b) the black quartz glass has a specific heat of 1090 to 1130 J / kg·K at a temperature of 500°C; (c) the black quartz glass has a specific heat of 7×10 －７ ~8 x 10 －７ m ２ / s; (d) the black quartz glass has a thermal conductivity of 1.5 to 2.1 W / mK at a temperature of 500°C; (e) the black quartz glass has a thermal diffusivity of 2 x 10 in the range of 30°C to 600°C. －７ ~12 x 10 －７ / °C, (f) the black quartz glass has a thickness of 1 mm and an optical transmittance of 0.5% or less at wavelengths of 200 to 3000 nm, (g) in a machining test of the black quartz glass, the number of chips with a maximum length of 0.5 mm or more occurring is 1 / 100 cm ２ and the number of discolored areas with a maximum length of 1 mm or more is 1 per 100 cm ２ Here, the machining test is carried out by polishing the surface of the black quartz glass to a roughness Ra of 0.8 μm. (h) In a heating test of the black quartz glass, the number of bubbles having a maximum length of 1 mm or more is 1 / 100 cm. ２ and the number of discolored areas with a maximum length of 1 mm or more is 1 per 100 cm ２ Here, the heating test is carried out by heating the black quartz glass at 1370°C for 3 hours. (i) In the quenching / thermal shock test of the black quartz glass, the number of chips with a maximum length of 0.5 mm or more is 1 / 100 cm ２The quenching / thermal shock test is carried out by polishing both sides of a 75 mm square x 10 mm thick test piece to a roughness Ra of 0.8 μm, heating the polished test piece at 900°C for 30 minutes, and then immersing it in water at room temperature. [7] The silica portion in the glass structure is 10 to 40 mass% of fumed silica and 0.05 to 3.0 μm D based on the total mass of the silica portion. ５０ 10 to 40 mass% of a first spherical silica having a D of 0.25 to 15 μm ５０ The remaining second spherical silica has a D ５０ is the D of the first spherical silica ５０ [8] The black quartz glass according to any one of [1] to [6], wherein the D of the first spherical silica is 5 times or more. ５０ D of 1 / 5 or more １０ and D ５０ D less than 10 times ９０ The second spherical silica has a D of the second spherical silica. ５０ D of 1 / 5 or more １０ and D ５０ D less than 10 times ９０ [9] The black quartz glass according to [7], wherein at least a part of Si in the glass structure is present as Si particles, and the Si particles are D ５０

[10] The black quartz glass according to any one of [1] to [8], having a particle size distribution in which the particle size is 5 to 10 μm.

[11] At least a part of the SiO in the glass structure is present as SiO particles, and the SiO particles are D ５０

[11] A method for producing the black quartz glass according to any one of [1] to [9], which has a particle size distribution of 3 to 15 μm.

[11] A method for producing the black quartz glass according to any one of [1] to

[10] , comprising: mixing and consolidating Si powder and silica powder to which SiO powder has been added, or silica powder to which Si powder has been added, pressurizing the powder obtained by the mixing and consolidation to produce a pressed compact, and sintering the pressed compact in air at a maximum temperature of 1300 to 1400°C to obtain the black quartz glass, wherein the amount of Si powder added is 0.5 to 10 parts by mass relative to 100 parts by mass of the silica powder, and the amount of SiO powder added is 0 to 5 parts by mass relative to 100 parts by mass of the silica powder, and the silica powder is 10 to 40% by mass of fumed silica based on the total mass of the silica powder, and ５０ 10 to 40 mass% of a first spherical silica having a D of 0.25 to 15 μm ５０ and the remaining second spherical silica having D ５０ is the D of the first spherical silica ５０

[12] The first spherical silica has a D of the first spherical silica of ５０ D of 1 / 5 or more １０ and D ５０ D less than 10 times ９０ The second spherical silica has a D of the second spherical silica. ５０ D of 1 / 5 or more １０ and D ５０ D less than 10 times ９０

[13] The manufacturing method according to

[11] , wherein the Si powder is D ５０

[14] The method according to

[11] or

[12] , wherein the SiO powder has a particle size distribution of 5 to 10 μm. ５０

[15] The manufacturing method according to any one of

[11] to

[13] , wherein the silica powder contains one or more types of spherical silica having different particle sizes other than the first and second spherical silica.

[16] The manufacturing method according to any one of

[11] to

[15] , wherein the sintering is carried out for 0.5 to 5 hours.

[17] The manufacturing method according to any one of

[11] to

[16] , wherein the fumed silica satisfies one or more of the following (i) to (iv): (i) the fumed silica has a particle size distribution of 0.03 to 0.08 g / cm ３ (ii) the fumed silica has a tapped bulk density of 50 to 100 m ２ / g, (iii) the fumed silica has an OH group concentration of 0.5 to 1.0 mass%, and (iv) the content of metal impurities in the fumed silica is each 1 ppm or less.

[18] The manufacturing method according to any one of

[11] to

[17] , wherein the mixed compaction is carried out so that the tapped bulk density of the powder obtained by mixed compaction is 5 to 20 times the tapped bulk density of the fumed silica.

[19] A black quartz glass member manufactured from the black quartz glass according to any one of [1] to

[10] .

[20] The black quartz glass member according to

[19] , which is an optical component, a light-shielding component, an infrared absorbing component, or a heat storage component.

[21] The black quartz glass member according to

[20] , which is an optical component such as a spectroscopic cell, a projector reflector, or an optical fiber connector, or a light-shielding component for semiconductor manufacturing equipment or infrared heating equipment.

[22] A product comprising the black quartz glass member according to any one of

[19] to

[21] .

[0021] According to the present invention, there is provided black quartz glass that has excellent light-shielding properties as well as excellent mechanical strength, heat resistance, and thermal shock resistance, that does not cause contamination in processes in which the black quartz glass is used, that can be made large, and that maintains sufficient color uniformity even when made large.

[0022] According to another aspect of the present invention, there is provided a method for producing black quartz glass, which enables the black quartz glass of the present invention to be produced with excellent productivity and in large sizes.

[0023] Furthermore, according to another aspect of the present invention, there are provided black quartz glass members made from the black quartz glass of the present invention and products containing the same.

[0024] 1 is a microscopic image of a cross section of the black quartz glass of Example 1. FIG. 2 is a microscopic image of a cross section of the black quartz glass of Comparative Example 3.

[0025] [Black quartz glass] The black quartz glass of the present invention is black quartz glass containing 0.5 to 10 parts by mass of Si and 0 to 5 parts by mass of SiO per 100 parts by mass of silica, and is substantially free of pores in the glass structure, and the number of pores with a diameter of 30 μm or more is 5 / mm in a microscopic image of a cross section of the glass structure. ２ The black quartz glass of the present invention has a main content of silica (SiO ２ It is a sintered body of a mixed powder containing silica (SiO) powder and a small amount of silicon (Si) powder and optionally silicon monoxide (SiO) powder, and has a glass structure in which Si regions and SiO regions (if present) are dispersed in a silica matrix region.

[0026] The content of Si in the glass structure is 0.5 to 10 parts by mass relative to 100 parts by mass of silica. When the content of Si is 0.5 parts by mass or more, the SCE reflectance is sufficiently reduced, and the L ＊ a ＊ b ＊ Lightness L in the color system ＊ is sufficiently reduced, and the saturation a ＊ and b ＊ The absolute value of can be sufficiently reduced, resulting in a blacker color tone of the black quartz glass and improved light-blocking properties. By keeping the Si content at 10 parts by mass or less, sintering of the raw material powder in the manufacturing process of the black quartz glass is not inhibited, and the mechanical strength of the sintered black quartz glass of the present invention can be sufficiently ensured.

[0027] The Si content is preferably in the range of 1.0 to 5 parts by mass, more preferably 1.5 to 3 parts by mass.

[0028] At least a portion of the Si in the glass structure of the black quartz glass of the present invention is present as Si particles, and the Si particles are ５０ It is preferable that the particle size distribution of the Si particles is such that the volume-based median diameter is 5 to 10 μm. ５０ is 5 μm or more, the saturation a ＊ and b ＊ The absolute value of D of the Si particles becomes smaller, the color tone of the black quartz glass becomes darker, and the light-shielding properties are further improved. ５０ is 10 μm or less, the lightness L ＊ The black quartz glass of the present invention has a lower SCE reflectance and a better light-shielding property. Furthermore, the sintering of the raw material powder in the manufacturing process of the black quartz glass is not inhibited, and the mechanical strength of the sintered body of the black quartz glass of the present invention can be more sufficiently ensured.

[0029] The Si particles are D １０ is 1 μm or more and D ９５ It is preferable that the particle size distribution is 30 μm or less, and D ５０ is 5 to 10 μm, and D １０ is 1 μm or more and D ９５ It is particularly preferable that the Si particles have a particle size distribution in which the D １０ is 1 μm or more and D ９５ is 30 μm or less, the saturation a ＊ and b ＊ The absolute value of tends to be smaller.

[0030] D of Si particles ５０ is preferably 5.5 to 9.5 μm, more preferably 6.0 to 9.0 μm. １０ is preferably 2 μm or more, more preferably 3 μm or more. ９５ is preferably 20 μm or less, more preferably 15 μm or less.

[0031] The content of SiO in the glass structure is 0 to 5 parts by mass relative to 100 parts by mass of silica. SiO does not necessarily have to be present, but it is preferable that SiO is contained. By containing SiO, the SCE reflectance is further reduced, and the L ＊ a ＊ b ＊ Lightness L in the color system ＊ Further reduce the saturation a ＊ and b ＊ By making the SiO content 5 parts by mass or less, the sintering of the raw material powder in the manufacturing process of the black quartz glass is not inhibited, and the mechanical strength of the sintered body of the black quartz glass of the present invention can be sufficiently ensured.

[0032] The SiO content is preferably in the range of 0.15 to 4.0 parts by mass, more preferably 0.20 to 3.0 parts by mass, and particularly preferably 0.30 to 2.0 parts by mass when the maximum temperature during sintering in the manufacturing process of the black quartz glass is 1300 to 1390° C. The SiO content is preferably in the range of 0 to 0.15 parts by mass, more preferably 0 to 0.10 parts by mass when the maximum temperature is 1390 to 1400° C., and SiO may not be present.

[0033] When SiO is present in the glass structure of the black quartz glass of the present invention, at least a part of the SiO is present as SiO particles, and the SiO particles are ５０ It is preferable that the particle size distribution of the SiO particles is 3 to 15 μm. ５０ is 3 μm or more, the saturation a ＊ and b ＊ The absolute value of D of the SiO particles becomes smaller, the color tone of the black quartz glass becomes darker, and the light-shielding properties are further improved. ５０ is 15 μm or less, the lightness L ＊ The black quartz glass of the present invention has a lower SCE reflectance and a better light-shielding property. Furthermore, the sintering of the raw material powder in the manufacturing process of the black quartz glass is not inhibited, and the mechanical strength of the sintered body of the black quartz glass of the present invention can be more sufficiently ensured.

[0034] SiO particles are D １０ is 1 μm or more and D ９０ It is preferable that the particle size distribution is 35 μm or less, and D ５０ is 3 to 15 μm, and D １０ is 1 μm or more and D ９０ It is particularly preferred that the SiO particles have a particle size distribution in which the D １０ is 1 μm or more and D ９０ is 35 μm or less, the saturation a ＊ and b ＊ The absolute value of tends to be smaller.

[0035] D of SiO particles ５０ is preferably 4.5 to 13 μm, more preferably 5.0 to 11 μm. １０ is preferably 2 μm or more, more preferably 3 μm or more. ９０ is preferably 20 μm or less, more preferably 15 μm or less.

[0036] In the glass structure of the black quartz glass of the present invention, the remainder excluding Si and SiO is silica.

[0037] The silica portion in the glass structure of the black quartz glass of the present invention is 10 to 40 mass % of fumed silica and 0.05 to 3.0 μm D based on the total mass of the silica portion. ５０ 10 to 40 mass% of a first spherical silica having a D of 0.25 to 15 μm ５０ The remaining second spherical silica has a D of the second spherical silica. ５０ is the D of the first spherical silica ５０ It is preferable that the value is 5 times or more.

[0038] In the black quartz glass of the present invention, there are substantially no pores in the glass structure. "Substantially no pores" means that in a microscopic image of a cross section of the glass structure, the number of pores with a diameter of 30 μm or more is 5 / mm ２ That is, in the black quartz glass of the present invention, the number of pores with a diameter of 30 μm or more is 5 / mm in a microscopic image of a cross section of the glass structure. ２The number of pores in the cross section of the glass structure is 5 / mm or less. ２ By keeping the thickness below 1 / 2 mm, the number of pores that can become the starting points for mechanical or thermal destruction is reduced, and the black quartz glass of the present invention exhibits excellent mechanical strength, heat resistance, and thermal shock resistance.

[0039] The number of pores in the cross section of the glass structure is preferably as small as possible, preferably 4 pores / mm , from the viewpoint of obtaining better mechanical strength, heat resistance, and thermal shock resistance. ２ More preferably, 2 particles / mm ２ More preferably, it is 1 particle / mm or less. ２ or less, and most preferably 0 pieces / mm ２ is.

[0040] The black quartz glass of the present invention has an SCE reflectance of 10% or less at wavelengths of 350 nm to 750 nm. The SCE reflectance is measured in accordance with JIS Z8722. With an SCE reflectance of 10% or less, the black quartz glass of the present invention exhibits excellent light-blocking properties.

[0041] From the viewpoint of obtaining better light-shielding properties, the SCE reflectance is preferably lower, preferably 9% or less, more preferably 8% or less. The lower limit of the SCE reflectance is not particularly limited and can be 1% or more or 2% or more.

[0042] The black quartz glass of the present invention preferably has a water absorption rate of 0.1% or less. The water absorption rate is another index for evaluating the number of pores in the black quartz glass; the lower the water absorption rate, the fewer the number of pores in the black quartz glass. By having a water absorption rate of 0.1% or less, the black quartz glass of the present invention exhibits superior mechanical strength, heat resistance, and thermal shock resistance.

[0043] The water absorption is preferably lower from the viewpoint of obtaining better mechanical strength, heat resistance, and thermal shock resistance, and is preferably 0.05% or less, more preferably 0.01% or less. The lower limit of the water absorption is not particularly limited, and can be 0.001% or more, or 0.002% or more.

[0044] The black quartz glass of the present invention preferably has a density where the difference in density compared to the theoretical density is 1% or less, expressed as an absolute value. The density difference compared to the theoretical density is another index for evaluating the number of pores in the black quartz glass; the smaller the density difference, the fewer the number of pores in the black quartz glass. The theoretical density refers to the density of an ideal glass calculated from the density of pure quartz glass and the amount of Si and SiO added; detailed calculation methods are explained in the Examples. With a density difference of 1% or less, expressed as an absolute value, the black quartz glass of the present invention exhibits superior mechanical strength, heat resistance, and thermal shock resistance.

[0045] The density difference is preferably as low as possible, preferably 0.5% or less, more preferably 0.1% or less, from the viewpoint of obtaining better mechanical strength, heat resistance, and thermal shock resistance. The lower limit of the density difference is not particularly limited, and can be 0.01% or more, or 0.02% or more.

[0046] In the black quartz glass of the present invention, from the viewpoint of obtaining particularly excellent mechanical strength, heat resistance, and thermal shock resistance, the number of pores in the cross section of the glass structure is set to 5 / mm ２ It is preferable that the water absorption is 0.1% or less, and the density difference compared to the theoretical density is 1% or less in absolute value.

[0047] The black quartz glass of the present invention is L ＊ a ＊ b ＊ In the color system, the lightness L is 30 or less ＊ It is preferable that the lightness L ＊ By making the L value 30 or less, not only will color unevenness not occur, but the black quartz glass will be able to exhibit a sufficient black color without causing light transmission, stray light, or scattering. ＊ a ＊ b ＊ In the color system, saturation a of 3.5 or less ＊ and saturation b less than 4 ＊ It is preferable that the absolute value of the lightness L ＊ , saturation a ＊ and b ＊When the reflectance is in the above range, the color tone of the black quartz glass of the present invention becomes darker, and the black quartz glass can have a lower SCE reflectance.

[0048] Lightness L ＊ From the viewpoint of obtaining a blacker color tone, the lightness L is preferably 28 or less, and more preferably 20 or less. ＊ The lower limit of saturation a is not particularly limited, and may be 15 or more, or 16 or more. ＊ From the viewpoint of obtaining a blacker color tone, the absolute value of saturation a is preferably 2.8 or less, and more preferably 2.5 or less. ＊ The lower limit of the absolute value of saturation b is not particularly limited, and may be 1.8 or more, or 2.0 or more. ＊ From the viewpoint of obtaining a blacker color tone, the absolute value of saturation b is preferably 3.8 or less, and more preferably 3.7 or less. ＊ The lower limit of the absolute value of is not particularly limited, and may be 3.0 or more, or 3.5 or more.

[0049] The content of metal impurities in the black quartz glass of the present invention is preferably 1 ppm or less by mass. Silicon (Si), which constitutes the black quartz glass of the present invention, is not included in the meaning of "metal impurities." Having a content of metal impurities of 1 ppm or less reduces the risk of the black quartz glass becoming a source of contamination in various processes using the black quartz glass (e.g., semiconductor production lines). Furthermore, even when the black quartz glass of the present invention is used as a component of an optical analysis device, there is no adverse effect on the accuracy of optical analysis because there is no influence of fluorescence generated from the metal impurities. The content of metal impurities can be analyzed, for example, by atomic absorption spectrometry or other methods.

[0050] The black quartz glass of the present invention preferably satisfies one or more of the following (a) to (i), more preferably two or more, three or more, or four or more, and most preferably all of them. This further improves the light-shielding properties, mechanical strength, heat resistance, and thermal shock resistance, and further enhances the performance as a component. (a) The black quartz glass has a density of 2.19 to 2.30 g / cm ３(b) the black quartz glass has a specific heat of 1090 to 1130 J / kg·K at a temperature of 500°C; (c) the black quartz glass has a specific heat of 7×10 －７ ~8 x 10 －７ m ２ / s; (d) the black quartz glass has a thermal conductivity of 1.5 to 2.1 W / mK at a temperature of 500°C; (e) the black quartz glass has a thermal diffusivity of 2 x 10 in the range of 30°C to 600°C. －７ ~12 x 10 －７ / °C, (f) the black quartz glass has a thickness of 1 mm and an optical transmittance of 0.5% or less at wavelengths of 200 to 3000 nm, (g) in a machining test of the black quartz glass, the number of chips with a maximum length of 0.5 mm or more occurring is 1 / 100 cm ２ and the number of discolored areas with a maximum length of 1 mm or more is 1 per 100 cm ２ Here, the machining test is carried out by polishing the surface of the black quartz glass to a roughness Ra of 0.8 μm. (h) In a heating test of the black quartz glass, the number of bubbles having a maximum length of 1 mm or more is 1 / 100 cm. ２ and the number of discolored areas with a maximum length of 1 mm or more is 1 per 100 cm ２ Here, the heating test is carried out by heating the black quartz glass at 1370°C for 3 hours. (i) In the quenching / thermal shock test of the black quartz glass, the number of chips with a maximum length of 0.5 mm or more is 1 / 100 cm ２ The quenching / thermal shock test is carried out by polishing both surfaces of a test piece measuring 75 mm square and 10 mm thick to a roughness Ra of 0.8 μm, heating the polished test piece at 900° C. for 30 minutes, and then immersing it in water at room temperature.

[0051] (a) The black quartz glass of the present invention has a density of 2.19 to 2.30 g / cm ３By having a density within the above range, the density of the black quartz glass is close to the theoretical density, the number of pores in the black quartz glass is reduced, and better mechanical strength, heat resistance, and thermal shock resistance are obtained. The density is preferably 2.17 to 2.27 g / cm ３ More preferably, it is in the range of 2.18 to 2.25 g / cm ３ The range is.

[0052] (b) The black quartz glass of the present invention preferably has a specific heat of 1090 to 1130 J / kg K at a temperature of 500°C. The specific heat at a temperature of 500°C can be measured by differential scanning calorimetry (DSC). The specific heat is preferably in the range of 1095 J / kg K or more and 1120 J / kg K or less, and more preferably in the range of 1100 J / kg K or more and 1114 J / kg K or less.

[0053] (c) The black quartz glass of the present invention has a viscosity of 7×10 at a temperature of 500°C. －７ ~8 x 10 －７ m ２ The thermal diffusivity at a temperature of 500°C can be measured by the flash method in accordance with JIS R1611. The thermal diffusivity is preferably 7.2 × 10 －７ m ２ / s or more, 7.9×10 －７ m ２ / s or less, and more preferably 7.4 × 10 －７ m ２ / s or more, 7.6×10 －７ m ２ / s or less.

[0054] (d) The black quartz glass of the present invention preferably has a thermal conductivity of 1.5 to 2.1 W / mK at a temperature of 500°C. The thermal conductivity at a temperature of 500°C can be calculated by multiplying the density of the sintered body by the specific heat and the thermal diffusivity. The thermal conductivity is preferably in the range of 1.6 W / mK or more and 2.0 W / mK or less, and more preferably in the range of 1.7 W / mK or more and 1.9 W / mK or less.

[0055] (e) The black quartz glass of the present invention has a viscosity of 2×10 in the range of 30° C. to 600° C. －７~12 x 10 －７ The thermal expansion coefficient at temperatures from 30°C to 600°C can be measured by thermomechanical analysis (TMA). The thermal expansion coefficient is preferably 4×10 －７ / ℃ or more, 11 x 10 －７ / °C or less, more preferably 6 × 10 －７ / ℃ or more, 10 × 10 －７ / °C or less.

[0056] (f) The black quartz glass of the present invention preferably has a light transmittance of 0.5% or less at a wavelength of 200 to 3000 nm at a thickness of 1 mm. The light transmittance at a wavelength of 200 to 3000 nm is measured using a spectrophotometer. With a light transmittance of 0.5% or less, the black quartz glass exhibits better light-blocking properties. From the viewpoint of obtaining better light-blocking properties, the light transmittance is preferably low, preferably 0.4% or less, and more preferably 0.3% or less. The lower limit of the light transmittance is not particularly limited, and can be 0.01% or more, or 0.1% or more.

[0057] (g) In a machining test of the black quartz glass of the present invention, the number of chippings (depressions due to defects) with a maximum length of 0.5 mm or more was 1 / 100 cm ２ The number of discolored areas with a maximum length of 1 mm or more is 1 per 100 cm ２ The number of chippings and discolored areas is preferably 1 / 100cm or less. ２ The following provides better mechanical strength, heat resistance, and thermal shock resistance. Details of the machining test will be described in the Examples.

[0058] The number of chippings is preferably 0.5 / 100cm ２ More preferably, it is 0.1 pieces / 100 cm or less. ２ The lower limit of the number of chippings is not particularly limited, but it is preferable that no chipping occurs. The number of discolored areas is preferably 0.5 / 100 cm ２ More preferably, it is 0.1 pieces / 100 cm or less. ２The lower limit of the number of discolored areas is not particularly limited, and it is preferable that no discolored areas occur.

[0059] (h) In a heating test of the black quartz glass of the present invention, the number of bubbles having a maximum length of 1 mm or more is 1 / 100 cm ２ The number of discolored areas with a maximum length of 1 mm or more is 1 per 100 cm ２ The number of bubbles and discolored areas is preferably 1 / 100 cm or less. ２ By satisfying the following conditions, better mechanical strength, heat resistance, and thermal shock resistance can be obtained. Details of the heating test will be described in the Examples.

[0060] The number of bubbles generated is preferably 0.5 / 100 cm ２ More preferably, it is 0.1 pieces / 100 cm or less. ２ The lower limit of the number of bubbles generated is not particularly limited, but it is preferable that no bubbles are generated. The number of discolored areas generated is preferably 0.5 / 100 cm ２ More preferably, it is 0.1 pieces / 100 cm or less. ２ The lower limit of the number of discolored areas is not particularly limited, and it is preferable that no discolored areas occur.

[0061] (i) In the quenching / thermal shock test of the black quartz glass of the present invention, the number of chips with a maximum length of 0.5 mm or more is 1 / 100 cm ２ It is preferable that the mass change is 10 ppm or less. The number of chippings is 1 chip / 100 cm. ２ The quenching / thermal shock test is described in detail in the Examples section, and the mass change is 10 ppm or less, thereby achieving superior mechanical strength, heat resistance, and thermal shock resistance.

[0062] The number of chippings is preferably 0.5 / 100cm ２ More preferably, it is 0.1 pieces / 100 cm or less. ２The lower limit of the number of chippings is not particularly limited, and it is preferable that no chipping occurs. The mass change is preferably 8 ppm or less, more preferably 6 ppm or less, and even more preferably 4 ppm or less. The lower limit of the mass change is not particularly limited, and can be 0.5 ppm or more or 1 ppm or more.

[0063] The black quartz glass of the present invention has a coefficient of thermal expansion as small as that of ordinary quartz glass when used in environments requiring dimensional accuracy at high temperatures, and other thermal properties are also equivalent to those of ordinary quartz glass. Therefore, the black quartz glass of the present invention can be used in the same environments as ordinary quartz glass.

[0064] The black quartz glass of the present invention is particularly useful as a spectroscopic cell for optical analysis, a projector reflector, an optical fiber connector, or a light-shielding member, an infrared-absorbing member, or a heat-storing member for semiconductor manufacturing equipment or infrared heating equipment, although the uses of the black quartz glass are not limited to these components.

[0065] The black quartz glass of the present invention does not contain metal impurities and is therefore useful as a component of heat treatment equipment used in semiconductor manufacturing. For example, in a wafer heat treatment equipment, by constructing the parts other than the infrared-transmitting window out of the black quartz glass of the present invention, it is possible to efficiently block heat radiated outside the furnace. As a result, energy efficiency is improved and the temperature distribution inside the furnace is made uniform.

[0066] The black quartz glass of the present invention can be produced by the production method of the present invention described below.

[0067] [Method for manufacturing black quartz glass] The method for manufacturing black quartz glass of the present invention is as follows: A manufacturing method comprising mixing and consolidating Si powder and silica powder to which SiO powder has been added, or silica powder to which Si powder has been added, pressurizing the powder obtained by mixing and consolidating to produce a pressed compact, and sintering the pressed compact in air at a maximum temperature of 1300 to 1400°C to obtain black quartz glass, wherein the amount of Si powder added is 0.5 to 10 parts by mass per 100 parts by mass of silica powder, the amount of SiO powder added is 0 to 5 parts by mass per 100 parts by mass of silica powder, and the silica powder is 10 to 40% by mass of fumed silica and a D of 0.05 to 3.0 μm based on the total mass of the silica powder. ５０ 10 to 40 mass% of a first spherical silica having a D of 0.25 to 15 μm ５０ and the remaining second spherical silica having D ５０ is the D of the first spherical silica ５０ This is more than five times the amount.

[0068] Si powder means powder of elemental silicon, and SiO powder means powder of silicon monoxide.

[0069] Fumed silica is a finely powdered silica obtained by burning silicon tetrachloride gas or the like in the gas phase.

[0070] The spherical silica is not particularly limited as long as it has a spherical shape and a particle size within the above-mentioned range, and may be silica powder synthesized by a dry method or silica powder synthesized by a wet method. Examples of silica powder synthesized by a dry method include spherical high-purity synthetic fused silica obtained by reacting silicon tetrachloride gas or the like in the gas phase. Examples of silica powder synthesized by a wet method include silica obtained by hydrolyzing and condensing silicon alkoxide in water or a mixed medium containing water and an organic solvent to produce a silica cake, and then calcining the silica cake. Synthetic fused silica is preferred as the spherical silica because of its high circularity of the silica particles.

[0071] The manufacturing method of the present invention can provide black quartz glass that has excellent light-shielding properties, as well as excellent mechanical strength, heat resistance, and thermal shock resistance, is free from the risk of causing contamination in the processes in which the black quartz glass is used, can be made into large sizes, and maintains sufficient color uniformity even when made into large sizes. The reason for this is not clear, but is thought to be as follows.

[0072] The black quartz glass of the present invention is a sintered body of silica powder to which Si powder and SiO powder have been added, or a sintered body of silica powder to which Si powder has been added, and has a glass structure in which Si regions and SiO regions (if present) are dispersed in a silica matrix region. Due to the presence of Si and SiO regions or Si regions dispersed in the matrix region, the black quartz glass has an SCE reflectance of 10% or less and exhibits excellent light-blocking properties. The color uniformity of the black quartz glass can be sufficiently ensured by thoroughly mixing the raw material powders before sintering.

[0073] Fumed silica typically has a small particle size of 10 to 30 nm, a very low bulk density, and is therefore unsuitable for granulation or molding. The density of a sintered body obtained by sintering fumed silica is low and is not satisfactory as quartz glass. In contrast, in the present invention, fumed silica is mixed with silica powders (first and second spherical silica) having larger particle sizes. The fumed silica functions as a sintering agent that promotes sintering of the silica powder while filling the gaps between the silica powders having larger particle sizes, thereby suppressing the generation of pores in the sintered body.

[0074] Furthermore, the silica powder having a particle size larger than that of fumed silica contains multiple types of spherical silica powder having small average particle sizes and different from each other, which further reduces the gaps between the silica powder particles that form the matrix of the sintered body and suppresses the generation of pores in the sintered body.

[0075] It is believed that the suppression of pore formation in the sintered body as described above resulted in a sintered body that was substantially free of pores and had a density that nearly matched the theoretical density. Because there are substantially no pores that could be the starting point for mechanical or thermal destruction, the black quartz glass of the present invention exhibits excellent mechanical strength, heat resistance, and thermal shock resistance.

[0076] In addition, the black quartz glass of the present invention is composed essentially of silicon and oxygen and does not contain elements (e.g., transition metals and carbon) that have a significant impact as impurities in semiconductor manufacturing processes, so there is no risk of contamination. Furthermore, the black quartz glass of the present invention can be manufactured simply by molding the powder into the desired shape and sintering it at 1,400°C or less, which simplifies the manufacturing process and allows for energy-saving production. Therefore, the black quartz glass of the present invention can be flexibly manufactured in large sizes and can be manufactured with good productivity.

[0077] The manufacturing method of the present invention has the advantage that it can be carried out at a relatively low temperature range of 1300 to 1400°C maximum temperature. Normally, when pores in the glass structure are eliminated in the manufacture of quartz glass by the sintering method, it is necessary to raise the maximum temperature to about 1800°C, melt at least a portion of the raw material, and remove bubbles. If raw material powder to which Si powder and SiO powder have been added is heated to 1800°C, the Si and SiO will melt and dissolve in the surrounding silica (SiO ２ ), and the resulting quartz glass is not black. However, the manufacturing method of the present invention surprisingly allows sintering at a relatively low temperature where Si and SiO do not melt. This is thought to be because the raw material powder for sintering is composed of a specific mixed powder, i.e., a mixed powder in which Si powder and SiO powder, or only Si powder, is added at a specific concentration to a silica powder containing fumed silica, first spherical silica, and second spherical silica.

[0078] Furthermore, in the manufacturing method of the present invention, the presence of fine fumed silica in the gaps between the silica powder particles makes the structure of the sintered body more uniform, and the heating time to the maximum temperature can be shortened.

[0079] The manufacturing method of the present invention will be described below. The manufacturing method of the present invention includes mixing and consolidating Si powder and silica powder to which SiO powder has been added, or silica powder to which Si powder has been added.

[0080] The amount of Si powder added is 0.5 to 10 parts by mass relative to 100 parts by mass of silica powder. When the amount of Si powder added is 0.5 parts by mass or more, the SCE reflectance is sufficiently reduced, and the L ＊ a ＊ b ＊ Lightness L in the color system ＊ is sufficiently reduced, and the saturation a ＊ and b ＊ The absolute value of can be sufficiently reduced, resulting in a blacker color tone of the black quartz glass and improved light-blocking properties. By adding 10 parts by mass or less of Si powder, sintering of the raw material powder in the manufacturing process of the black quartz glass is not inhibited, and the mechanical strength of the sintered black quartz glass of the present invention can be sufficiently ensured.

[0081] The amount of Si powder added is preferably 1.0 to 6.0 parts by mass, and more preferably 1.5 to 4.0 parts by mass.

[0082] The Si powder is D ５０ It is preferable that the particle size distribution of the Si powder is 5 to 10 μm. ５０ is 5 μm or more, the saturation a ＊ and b ＊ The absolute value of D of the Si powder becomes smaller, the color tone of the black quartz glass becomes darker, and the light-shielding properties are further improved. ５０ is 10 μm or less, the lightness L ＊ The black quartz glass of the present invention has a lower SCE reflectance and a better light-shielding property. Furthermore, the sintering of the raw material powder in the manufacturing process of the black quartz glass is not inhibited, and the mechanical strength of the sintered body of the black quartz glass of the present invention can be more sufficiently ensured.

[0083] The Si powder is D １０ is 1 μm or more and D ９５ It is preferable that the particle size distribution is 30 μm or less, and D ５０ is 5 to 10 μm, and D１０ is 1 μm or more and D ９５ It is particularly preferable that the Si powder has a particle size distribution in which the D １０ is 1 μm or more and D ９５ is 30 μm or less, the saturation a ＊ and b ＊ The absolute value of tends to be smaller.

[0084] D of Si powder ５０ is preferably 5.5 to 9.5 μm, more preferably 6.0 to 9.0 μm. １０ is preferably 2 μm or more, more preferably 3 μm or more. ９５ is preferably 20 μm or less, more preferably 15 μm or less.

[0085] The amount of SiO powder added is 0 to 5 parts by mass per 100 parts by mass of silica powder. Although SiO powder does not have to be added, it is preferable to add SiO powder. By adding SiO powder, the SCE reflectance can be further reduced, and the L ＊ a ＊ b ＊ Lightness L in the color system ＊ Further reduce the saturation a ＊ and b ＊ The absolute value of can be further reduced, resulting in a blacker color tone of the black quartz glass and improved light-blocking properties. By adding SiO powder in an amount of 5 parts by mass or less, sintering of the raw material powder in the manufacturing process of the black quartz glass is not inhibited, and the mechanical strength of the sintered black quartz glass of the present invention can be sufficiently ensured.

[0086] The amount of SiO powder added is preferably in the range of 0.15 to 4.0 parts by mass, more preferably 0.20 to 3.0 parts by mass, and particularly preferably 0.30 to 2.0 parts by mass when the maximum temperature during sintering in the manufacturing process of black quartz glass is 1300 to 1390° C. The amount of SiO powder added is preferably in the range of 0 to 0.15 parts by mass, more preferably 0 to 0.10 parts by mass when the maximum temperature is 1390 to 1400° C., and SiO powder may not be added.

[0087] When SiO powder is added, the SiO powder is ５０ It is preferable that the particle size distribution of the SiO powder is 3 to 15 μm. ５０ is 3 μm or more, the saturation a ＊ and b ＊ The absolute value of D of the SiO powder becomes smaller, the color tone of the black quartz glass becomes darker, and the light-shielding properties are further improved. ５０ is 15 μm or less, the lightness L ＊ The black quartz glass of the present invention has a lower SCE reflectance and a better light-shielding property. Furthermore, the sintering of the raw material powder in the manufacturing process of the black quartz glass is not inhibited, and the mechanical strength of the sintered body of the black quartz glass of the present invention can be more sufficiently ensured.

[0088] SiO powder is D １０ is 1 μm or more and D ９０ It is preferable that the particle size distribution is 35 μm or less, and D ５０ is 3 to 15 μm, and D １０ is 1 μm or more and D ９０ It is particularly preferable that the SiO powder has a particle size distribution in which the D １０ is 1 μm or more and D ９０ is 35 μm or less, the saturation a ＊ and b ＊ The absolute value of tends to be smaller.

[0089] SiO powder D ５０ is preferably 4.5 to 13 μm, more preferably 5.0 to 11 μm. １０ is preferably 2 μm or more, more preferably 3 μm or more. ９０ is preferably 20 μm or less, more preferably 15 μm or less.

[0090] The silica powder is a mixture of 10 to 40 mass% of fumed silica and 0.05 to 3.0 μm D based on the total mass of the silica powder. ５０ 10 to 40 mass% of a first spherical silica having a D of 0.25 to 15 μm ５０ and the remaining second spherical silica having D５０ is the D of the first spherical silica ５０ The content of each silica material is 5 times or more. When the content of each silica material is within the above range, the pores in the glass structure are reduced. Furthermore, better light blocking properties are obtained, sintering at a relatively low temperature is possible, the structure of the sintered body becomes more uniform, the heating time to the maximum temperature during sintering is shortened, and sufficient strength is easily obtained even when the black quartz glass is made large. There may be multiple types of first spherical silica contained in the silica powder. Alternatively, the first spherical silica as a whole is D ５０ The silica powder may be a mixed powder of plural kinds of spherical silica particles, with the particle diameter being in the range of 0.05 to 3.0 μm. The second spherical silica particles may be of plural kinds. Alternatively, the second spherical silica particles may be of a size of D ５０ It may also be a mixed powder of several types of spherical silica, so long as the particle size is in the range of 0.25 to 15 μm.

[0091] The content of fumed silica is preferably 13 to 35% by mass, more preferably 15 to 30% by mass. This further reduces the number of pores in the glass structure, resulting in better light-blocking properties, enabling sintering at relatively low temperatures, and making it easier to obtain sufficient strength even when the black quartz glass is large. For similar reasons, the content of the first spherical silica is preferably 13 to 35% by mass, more preferably 15 to 30% by mass. The content of the second spherical silica is the remainder of the silica material and is adjusted as appropriate.

[0092] In the manufacturing method of the present invention, the silica powder is spherical silica other than the first and second spherical silica, that is, D ５０The silica powder may contain one or more types of spherical silica (each type referred to as the third spherical silica, the fourth spherical silica, ... the nth spherical silica) having different particle sizes with a particle size of less than 0.05 μm or more than 15 μm. When the silica powder contains the third to nth spherical silicas, the content of the second spherical silica is the remainder excluding the total content of the fumed silica, the first spherical silica, and the third to nth spherical silicas. For example, the total content of the third to nth spherical silicas is preferably 0 to 20 mass %, more preferably 0 to 10 mass %, based on the total mass of the silica powder. From the viewpoints of suppressing the generation of pores in the glass structure and further improving the handleability of the silica material, the silica powder is preferably D ５０ It is preferable that the silica does not contain spherical silica having a particle size of less than 0.05 μm or more than 15 μm.

[0093] Additionally, in the manufacturing method of the present invention, it is preferable that the silica powder does not contain amorphous granular silica powder synthesized by a wet method (such as a precipitation method, a gel method, or a hydrolysis method). Silica powder synthesized by a wet method is usually non-spherical and has a relatively large particle size, which tends to cause gaps between silica particles and pores in the glass structure.

[0094] The first spherical silica has a D of 0.05 to 0.2 μm ５０ This reduces the number of pores in the glass structure, provides better light-shielding properties, allows sintering at a relatively low temperature, and makes it easier to obtain sufficient strength even when the black quartz glass is made large. ５０ is more preferably 0.08 to 0.18 μm, and further preferably 0.10 to 0.17 μm.

[0095] The first spherical silica is D of the first spherical silica ５０ D of 1 / 5 or more １０ and D ５０ D less than 10 times ９０ This reduces the number of pores in the glass structure, provides better light-shielding properties, allows sintering at a relatively low temperature, and makes it easier to obtain sufficient strength even when the black quartz glass is made large. １０is more preferably D of the first spherical silica ５０ The D of the first spherical silica is preferably 1 / 4 or more, and more preferably 1 / 3 or more. ９０ is more preferably D of the first spherical silica ５０ It is preferably 7 times or less, and more preferably 6 times or less.

[0096] In one embodiment, the first spherical silica has a D of 0.03 μm or more. １０ and D of 0.3 μm or less ９０ In particular, it is preferable that the first spherical silica has D １０ is preferably 0.04 μm or more, more preferably 0.05 μm or more. ９０ is preferably 0.25 μm or less, more preferably 0.23 μm or less.

[0097] The second spherical silica has a D of 0.30 to 14 μm. ５０ This reduces the number of pores in the glass structure, provides better light-shielding properties, allows sintering at a relatively low temperature, and makes it easier to obtain sufficient strength even when the black quartz glass is made large. ５０ is more preferably 0.50 to 12 μm, and further preferably 0.70 to 11 μm.

[0098] The second spherical silica is D of the second spherical silica ５０ D of 1 / 5 or more １０ and D ５０ D less than 10 times ９０ This reduces the number of pores in the glass structure, provides better light-shielding properties, allows sintering at a relatively low temperature, and makes it easier to obtain sufficient strength even when the black quartz glass is made large. １０ is more preferably D of the second spherical silica ５０ The D of the second spherical silica is preferably 1 / 4 or more, and more preferably 1 / 3 or more. ９０ is more preferably D of the second spherical silica ５０ It is preferably 7 times or less, and more preferably 6 times or less.

[0099] D of the second spherical silica５０ When the diameter of the second spherical silica particles is 5 to 15 μm, the diameter of the second spherical silica particles is 1 μm or more. １０ and D of 70 μm or less ９０ In particular, it is preferable that the second spherical silica has D １０ is preferably 1.5 μm or more, more preferably 2.0 μm or more. ９０ is preferably 65 μm or less, more preferably 60 μm or less.

[0100] D of the second spherical silica ５０ When the diameter of the second spherical silica particles is 0.25 to 5 μm, the diameter of the second spherical silica particles is 0.05 μm or more. １０ and D of 25 μm or less ９０ In particular, it is preferable that the second spherical silica has D １０ is preferably 0.08 μm or more, more preferably 0.10 μm or more. ９０ is preferably 20 μm or less, more preferably 15 μm or less.

[0101] In the production method of the present invention, the D of the second spherical silica ５０ is the D of the first spherical silica ５０ This reduces the number of pores in the glass structure, provides better light-shielding properties, allows sintering at a relatively low temperature, and makes it easier to obtain sufficient strength even when the black quartz glass is large. ５０ is the D of the first spherical silica ５０ The D of the second spherical silica is 300 times or less. ５０ is preferably the D of the first spherical silica ５０ The D of the second spherical silica is 7 times or more, 8 times or more, 9 times or more, 10 times or more, 20 times or more, or 30 times or more, and may be 40 times or more, 50 times or more, 55 times or more, 60 times or more, or 65 times or more. ５０ is preferably the D of the first spherical silica ５０ The concentration is 250 times or less, 200 times or less, or 150 times or less, and may be 140 times or less, 130 times or less, 120 times or less, 110 times or less, or 100 times or less.

[0102] The fumed silica preferably satisfies one or more of the following (i) to (iv), more preferably two or more or three or more, and most preferably all of them. This further reduces the number of pores in the glass structure, provides better light-shielding properties, allows sintering at a relatively low temperature, and makes it easier to obtain sufficient strength even when the black quartz glass is large. (i) The fumed silica is 0.03 to 0.08 g / cm ３ (ii) the fumed silica has a tapped bulk density of 50 to 100 m ２ / g, (iii) the fumed silica has an OH group concentration of 0.5 to 1.0 mass %, and (iv) the content of metal impurities in the fumed silica is each 1 ppm or less.

[0103] Powder mixing and consolidation is carried out by uniformly mixing dry, agglomerated Si powder and silica powder with SiO powder or Si powder alone. During this mixing, small particles fill the gaps between the larger particles, and powder consolidation progresses simultaneously. In the present invention, this operation is called "mixing and consolidation" because consolidation progresses simultaneously with mixing. As a result of mixing and consolidation, a mixed powder for compaction is obtained.

[0104] The mixed consolidation is preferably carried out so that the tapped bulk density of the mixed powder obtained by the mixed consolidation is 5 to 20 times that of the fumed silica. When the tapped bulk density of the mixed powder is 5 times or more that of the fumed silica, the density of the sintered body tends to be high. When the tapped bulk density of the mixed powder is 20 times or less that of the fumed silica, the strength of the molded body is less likely to decrease. The tapped bulk density of the mixed powder is preferably 6 to 15 times, more preferably 7 to 10 times, that of the fumed silica. The tapped bulk density of the mixed powder can be controlled by adjusting the blending of the raw materials and mixing conditions such as the powder mixing method and mixing time. The mixed consolidation can be carried out using a common mixing device such as an agitator mixer, ball mill, rocking mixer, cross mixer, or V-type mixer.

[0105] The manufacturing method of the present invention includes press-molding the powder obtained by mixing and compacting to produce a pressed compact.

[0106] The mixed powder obtained by mixing and consolidating can be pressure-molded into a desired shape. As the pressure-molding method, any method known in the ceramics field can be appropriately adopted. For example, dry methods such as die press molding and cold isostatic pressing can be used. A pressure of, for example, 10 to 300 MPa is appropriate. A pressure of 10 MPa or more will not cause the molded body to collapse and will maintain the yield during molding. A pressure of 300 MPa or less is desirable because it does not require large-scale equipment, is highly productive, and can reduce production costs.

[0107] The manufacturing method of the present invention involves sintering the pressed compact in air at a maximum temperature of 1300 to 1400° C. to obtain black quartz glass.

[0108] According to the manufacturing method of the present invention, a sintered body substantially free of pores in the glass structure can be obtained under conditions of a relatively low maximum temperature of 1300 to 1400°C. In particular, when the amount of SiO powder added is 0.15 to 5 parts by mass per 100 parts by mass of silica powder, the maximum temperature is 1305 to 1390°C, preferably 1310 to 1385°C, more preferably 1320 to 1380°C, even more preferably 1330 to 1375°C, and particularly preferably 1340 to 1370°C. When the amount of SiO powder added is 0 to 0.15 parts by mass per 100 parts by mass of silica powder, the maximum temperature is preferably 1390 to 1400°C. By keeping the maximum temperature of the sintering step at 1400°C or less, the Si and SiO in the raw material powder are incorporated into the glass structure without being oxidized, resulting in a sintered body with excellent light-blocking properties. Furthermore, since expensive equipment and components are not required, production costs can be reduced. By setting the maximum temperature of the sintering process to 1300°C or higher, a sintered body having excellent light-shielding properties, sufficient mechanical strength, and few pores within the structure can be obtained.

[0109] The sintering time at the maximum temperature can be adjusted appropriately taking into consideration the physical properties of the sintered body, and is, for example, in the range of 0.5 to 5 hours. When the sintering time is 0.5 hours or more, the density and bending strength tend to be less likely to decrease. When the sintering time is 5 hours or less, productivity improves and production costs tend to decrease.

[0110] The black quartz glass obtained in this way has no color unevenness and is sufficiently black to prevent light transmission, stray light, and scattering, making it useful in the optical field in general. In addition, it not only has extremely high light-shielding performance, but can also be bonded to ordinary quartz glass, making it suitable for producing quartz glass optical analysis cells.

[0111] [Black quartz glass member and product] The black quartz glass member of the present invention is a member manufactured from the black quartz glass of the present invention described above, and is, for example, an optical component, a light-shielding component, an infrared absorbing component, or a heat storage component. The black quartz glass member can be manufactured by processing a black quartz glass ingot with a known processing machine (such as a band saw, a wire saw, or a core drill) used in manufacturing quartz components. Alternatively, the black quartz glass member can be obtained as a sintered body by sintering a molded body formed in a mold corresponding to the shape of the desired component.

[0112] The black quartz glass member of the present invention has excellent light-shielding properties as well as excellent mechanical strength, heat resistance, and thermal shock resistance, and is therefore particularly suitable for use as an optical component such as a spectroscopic cell, a projector reflector, or an optical fiber connector, or as a light-shielding member for semiconductor manufacturing equipment or infrared heating equipment.

[0113] The product of the present invention is an instrument or device that includes the black quartz glass member of the present invention, such as an optical analysis instrument that includes the member as an optical component, a projector that includes the member as an optical component, a semiconductor manufacturing device that includes the member as a light-blocking member, and an infrared heating device that includes the member as an infrared-absorbing member.

[0114] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0115] The properties of the black quartz glass were measured or obtained by the following methods and procedures.

[0116] (1) Number of pores in cross section of glass structure A test piece was cut, and the cut surface was polished. Polishing was carried out in accordance with JIS B0601 until Ra was 0.20 μm or less. The polished surface was observed with a scanning electron microscope or optical microscope (observation magnification: approximately 500 to 3000 times) to obtain images (multiple images as necessary). The images were processed using the open-source, public domain image processing software "ImageJ" to measure the area A of each pore, and the area A was substituted into the following formula (1) to determine the pore diameter D. Pore diameter D = (4 × A / π) １／２ (1) Then, the number N of pores with a pore diameter D of 30 μm or more is counted, and the number N of pores and the total area TS (mm ２ The total area TS of the entire image was 600 mm ２ Pore ​​number density = N / TS (2)

[0117] (2) SCE Reflectance The SCE reflectance was measured on a 7 mm thick test piece using a spectrophotometer in accordance with JIS Z 8722. The maximum value in the wavelength range of 350 to 750 nm was shown as the result.

[0118] (3) Water Absorption The water absorption was measured using the Archimedes method in accordance with JIS A1509-3. Specifically, the water absorption was obtained according to the following formula (3): ａｑ represents the mass of the water-saturated test piece, and W ｄｒｙ represents the mass of the dry test piece. Water absorption rate = (W ａｑ -W ｄｒｙ ) / W ｄｒｙ (3)

[0119] (4) Density difference compared to theoretical density The density ρ of the black quartz glass (sintered body) was measured by the Archimedes method. Theoretical density ρ of black quartz glass ０ was calculated according to the following formula (4) using the charged amount of Si powder W1 (mass%) and the charged amount of SiO powder W2 (mass%). ０= 100 / (W1 / 2.32+W2 / 2.13+(100-W1-W2) / 2.20) (4) The density difference compared to the theoretical density is the density ρ of black quartz glass and the theoretical density ρ ０ The density difference was calculated according to the following formula (5): ０ -ρ| / ρ ０ (5)

[0120] (5) L ＊ a ＊ b ＊ Color system L ＊ a ＊ b ＊ Lightness L* and chroma a of the color system ＊ and b ＊ was measured using a spectrophotometer in accordance with JIS Z8722.

[0121] (6) Specific Heat The specific heat was measured by differential scanning calorimetry (DSC) at a temperature of 500°C using a test piece processed to a size of φ6 mm x thickness 1 mm.

[0122] (7) Thermal Diffusivity The thermal diffusivity was measured for a test piece processed to a size of φ10 mm×thickness 1 mm at a temperature of 500° C. by the flash method in accordance with JIS R1611.

[0123] (8) Thermal Conductivity The thermal conductivity was calculated using the following formula based on the specific heat and thermal diffusivity at a temperature of 500°C and the density ρ of the black quartz glass (sintered body): Thermal Conductivity = Specific Heat × Thermal Diffusivity × ρ

[0124] (9) Thermal Expansion Coefficient The thermal expansion coefficient was measured for a test piece processed to a size of 3 mm x 4 mm x 20 mm at 30 to 600°C by thermomechanical analysis (TMA) in accordance with JIS R1618.

[0125] (10) Light Transmittance The light transmittance was measured in the range of 200 to 3000 nm using a spectrophotometer on a 1 mm thick test piece. The maximum value in the wavelength range of 200 to 3000 nm was shown as the result.

[0126] (11) Machining test (evaluation of machining strength) A test piece measuring 75 mm square x 10 mm was cut from the sintered body, and the widest surface of the test piece was polished to a roughness Ra of 0.8 μm. The polished surface was observed visually or with an optical microscope, and the number of chippings with a maximum length of 0.5 mm or more and the number of discolored areas with a maximum length of 1 mm or more were counted. Based on the number of chippings and the total area of ​​the observation range, a 100 cm ２ The number of occurrences per area was calculated. The total area of ​​the observation range was 100 cm ２ If necessary, the total area of ​​the observation range can be adjusted by testing multiple test pieces prepared under the same conditions. The number of chipping and discoloration should both be 10 / 100cm. ２ When the mechanical strength of the black quartz glass is below the specified level, it is determined that the black quartz glass satisfies the objective of the present invention.

[0127] (12) Heating test (evaluation of heat resistance) The test specimen was heated at 1370°C for 3 hours, and then allowed to stand and cool naturally to room temperature (approximately 23 to 25°C). After cooling, the surface of the test specimen was observed visually or with an optical microscope, and the number of bubbles with a maximum length of 1 mm or more and the number of discolored areas with a maximum length of 1 mm or more were counted. Based on the number of bubbles and the total area of ​​the observation range, a 100 cm ２ The number of occurrences per area was calculated. The total area of ​​the observation range was 100 cm ２ If necessary, the total area of ​​the observation range can be adjusted by testing multiple test pieces prepared under the same conditions. The number of bubbles and discolored areas should both be 10 / 100cm. ２ When the heat resistance of the black quartz glass is below the specified level, it is determined that the black quartz glass satisfies the objective of the present invention.

[0128] (13) Quenching / Thermal Shock Test (Evaluation of Thermal Shock Resistance) Test pieces measuring 75 mm square and 10 mm thick were cut from the sintered body, and both sides of the test pieces were polished to a roughness Ra of 0.8 μm using the same polishing method as described in (1) above. The polished test pieces were heated at 900°C for 30 minutes, then placed in a water bath at room temperature (approximately 23 to 25°C), and after sufficient cooling, removed from the water bath. Water droplets adhering to the test pieces were thoroughly wiped off, and the test pieces were left to dry naturally. After drying, the surfaces of the test pieces were observed visually or with an optical microscope, and the number of chips with a maximum length of 0.5 mm or more was counted. Based on the number of chips and the total area of ​​the observation range, a 100 cm ２ The number of occurrences per area was calculated. The total area of ​​the observation range was 100 cm ２ A value of about 10 pieces / 100 cm is sufficient. If necessary, the total area of ​​the observation range can be adjusted by testing multiple test pieces prepared under the same conditions. In addition, the mass change (ppm) was calculated based on the mass of the test piece before and after the test. ２ If the change in mass is 10 ppm or less, the black quartz glass is judged to have thermal shock resistance at a level that satisfies the objective of the present invention.

[0129] [Raw Materials] The following raw materials were used: (1) Fumed silica: tapped bulk density 0.06 g / cm ３ , BET specific surface area 85m ２ / g, OH group concentration of 0.7 mass% and metal impurity content of 1 ppm or less. (2) Spherical Silica A:D ５０ 0.15 μm, D １０ 0.07 μm, D ９０ 0.20 μm and metal impurity content of 1 ppm or less. (3) Spherical silica B:D ５０ 11 μm, D １０ 3 μm, D ９０ (4) Silica powder synthesized by hydrolysis of silica alkoxide: D ５０ 80 μm, D １０ 48 μm, D ９５ 160 μm and metal impurity content of 1 ppm or less. (5) Si powder A:D ５０ 6 μm, D１０ 3 μm, D ９５ 13 μm and metal impurity content of 1 ppm or less. (6) Si powder B:D ５０ 7 μm, D １０ 4 μm, D ９５ 11 μm and metal impurity content of 1 ppm or less. (7) Si powder C:D ５０ 8 μm, D １０ 3 μm, D ９５ 20 μm and metal impurity content of 1 ppm or less. (8) Si powder D:D ５０ 6 μm, D １０ 4 μm, D ９５ 10 μm and metal impurity content of 1 ppm or less. (9) SiO powder A:D ５０ 5 μm, D １０ 2 μm, D ９０ 9 μm and metal impurity content of 1 ppm or less. (10) SiO powder B:D ５０ 10 μm, D １０ 5 μm, D ９０ 20 μm and metal impurity content of 1 ppm or less.

[0130] [Example 1] 20 mass% of fumed silica, 20 mass% of spherical silica A, and 60 mass% of spherical silica B were mixed to obtain a silica mixed powder. 2.0 mass parts of Si powder A and 0.2 mass parts of SiO powder A were added to 100 mass parts of silica powder, and the mixture was mixed and consolidated in a ball mill without using a solvent. The mixed powder had a density of 0.79 g / cm. ３ The mixed powder had a tapped bulk density of 1000 MPa and the content of each metal impurity was 1 ppm or less. The mixed powder was pressed at 90 MPa to produce a pressed compact. The pressed compact was heated and sintered in air at a maximum temperature of 1370°C for 3 hours to obtain a sintered body as black quartz glass.

[0131] [Example 2] 18% by mass of fumed silica, 18% by mass of spherical silica A, and 64% by mass of spherical silica B were mixed to obtain a silica mixed powder. 2.0 parts by mass of Si powder A was added to 100 parts by mass of the silica powder, and the mixture was mixed and consolidated in a ball mill without using a solvent. The mixed powder had a density of 0.79 g / cm. ３The mixed powder had a tapped bulk density of 1000 MPa and the content of each metal impurity was 1 ppm or less. The mixed powder was pressed at 90 MPa to produce a pressed compact. The pressed compact was heated and sintered in air at a maximum temperature of 1400°C for 3 hours to obtain a sintered body as black quartz glass.

[0132] [Comparative Example 1] 2.0 parts by mass of Si powder B and 0.5 parts by mass of SiO powder B were added to fumed silica per 100 parts by mass of silica powder, and the mixture was mixed and consolidated in a ball mill without using a solvent. The mixed powder had a density of 0.45 g / cm ３ The mixed powder had a tapped bulk density of 1000 MPa and the content of each metal impurity was 1 ppm or less. The mixed powder was pressed at 90 MPa to produce a pressed compact. The pressed compact was heated and sintered in air at a maximum temperature of 1250°C for 3 hours to obtain a sintered body as black quartz glass.

[0133] [Comparative Example 2] 1.0 part by mass of Si powder C and 1.0 part by mass of SiO powder B were added to fumed silica per 100 parts by mass of silica powder, and the mixture was mixed and consolidated in a ball mill without using a solvent. The mixed powder had a density of 0.45 g / cm ３ The mixed powder had a tapped bulk density of 1000 MPa and the content of each metal impurity was 1 ppm or less. The mixed powder was pressed at 90 MPa to produce a pressed compact. The pressed compact was heated and sintered in air at a maximum temperature of 1250°C for 3 hours to obtain a sintered body as black quartz glass.

[0134] Comparative Example 3: 50% by mass of fumed silica and 50% by mass of synthetic silica powder were mixed to obtain a silica mixed powder. 2.0 parts by mass of Si powder D and 0.5 parts by mass of SiO powder B were added to 100 parts by mass of the silica powder, and the mixture was mixed and consolidated in a ball mill without using a solvent. The mixed powder had a density of 0.60 g / cm. ３ The mixed powder had a tapped bulk density of 1000 MPa and the content of each metal impurity was 1 ppm or less. The mixed powder was pressed at 90 MPa to produce a pressed compact. The pressed compact was heated and sintered in air at a maximum temperature of 1300°C for 3 hours to obtain a sintered body as black quartz glass.

[0135] Comparative Example 4: 40% by mass of fumed silica, 18% by mass of spherical silica B, and 42% by mass of synthetic silica powder were mixed to obtain a silica mixed powder. 1.0 part by mass of Si powder A and 0.5 part by mass of SiO powder A were added to 100 parts by mass of silica powder, and the mixture was mixed and consolidated in a ball mill without using a solvent. The mixed powder had a density of 0.79 g / cm. ３ The mixed powder had a tapped bulk density of 1000 MPa and the content of each metal impurity was 1 ppm or less. The mixed powder was pressed at 90 MPa to produce a pressed compact. The pressed compact was heated and sintered in air at a maximum temperature of 1300°C for 3 hours to obtain a sintered body as black quartz glass.

[0136] Comparative Example 5: 0.5 parts by mass of Si powder B was added to fumed silica per 100 parts by mass of silica powder, and the mixture was mixed and consolidated in a ball mill without using a solvent. The content of metal impurities in the mixed powder was 1 ppm or less. The mixed powder was pressed at 90 MPa to produce a pressed compact. The pressed compact was heated and sintered in air at a maximum temperature of 1250°C for 3 hours to obtain a sintered body as black quartz glass.

[0137] [Results] The results of Examples 1 and 2 and Comparative Examples 1 to 5 are shown in Tables 1 to 5.

[0138]

[0139]

[0140]

[0141]

[0142]

[0143] [Explanation of Results] The maximum SCE reflectance was 5.2% in the black quartz glass of Example 1. The number of pores with a diameter of 30 μm or more in the cross section of the glass structure of the black quartz glass of Example 1 was 0.6 / mm ２It was confirmed that the glass structure was substantially free of pores. FIG. 1 is a microscopic image of a cross section of the black quartz glass of Example 1, and the black dots in the image represent pores. From FIG. 1, it can be seen that the glass structure of the black quartz glass of Example 1 is substantially free of pores. As a result, no defects were found in any of the machining test, heating test, and quenching / thermal shock test. This demonstrates that the black quartz glass of Example 1 has excellent light-shielding properties, as well as excellent mechanical strength, heat resistance, and thermal shock resistance.

[0144] In addition, the black quartz glass of Example 1 is composed essentially of silicon and oxygen and does not contain elements that have a significant impact as impurities in the semiconductor manufacturing process, so there is no risk of contamination. Furthermore, the black quartz glass of Example 1 can be manufactured simply by molding the powder into the desired shape and sintering it at 1,400°C or less, which simplifies the manufacturing process and allows for energy-saving production. Therefore, the black quartz glass of Example 1 can be flexibly manufactured in large sizes and can be manufactured with good productivity.

[0145] The black quartz glass of Example 1 was free from color unevenness and presented a sufficiently black color that did not transmit light, generate stray light, or scatter light. It was confirmed to be uniform by visual inspection and had an excellent aesthetic appearance.

[0146] In the black quartz glass of Example 2, the maximum SCE reflectance was 5.3%. In the cross section of the glass structure of the black quartz glass of Example 2, the number of pores with a diameter of 30 μm or more was 0.7 / mm ２ It was confirmed that the glass structure was substantially free of pores. As a result, no defects were found in any of the machining test, heating test, and quenching / thermal shock test. This demonstrates that the black quartz glass of Example 2 has excellent light-shielding properties, as well as excellent mechanical strength, heat resistance, and thermal shock resistance.

[0147] In addition, the black quartz glass of Example 2 is composed essentially of silicon and oxygen and does not contain elements that have a significant impact as impurities in the semiconductor manufacturing process, so there is no risk of contamination. Furthermore, the black quartz glass of Example 2 can be manufactured simply by molding the powder into the desired shape and sintering it at 1,400°C or less, which simplifies the manufacturing process and allows for energy-saving production. Therefore, the black quartz glass of Example 2 can be flexibly manufactured in large sizes and can be manufactured with good productivity.

[0148] The black quartz glass of Example 2 was free from color unevenness and presented a sufficiently black color that did not transmit light, generate stray light, or scatter light. It was confirmed to be uniform by visual inspection and had an excellent aesthetic appearance.

[0149] In the black quartz glass of Comparative Examples 1 to 4, the maximum SCE reflectance was 5.2 to 7.6%, and the light-shielding properties were sufficient. However, the number of pores with a diameter of 30 μm or more in the cross section of the glass structure was 5 / mm ２ Figure 2 is a microscopic image of the cross section of the black quartz glass of Comparative Example 3, and the black dots in the image are pores. Unlike Figure 1, many pores can be seen in Figure 2. As a result, serious defects were confirmed in at least one of the machining test, heating test, and quenching / thermal shock test for the black quartz glass of Comparative Examples 1 to 4.

[0150] In the black quartz glass of Comparative Example 5, the maximum SCE reflectance was as high as 13.0%. ＊ a ＊ b ＊ Color system lightness L ＊ Furthermore, the black quartz glass of Comparative Example 5 had uneven color and was insufficient in terms of light transmission and prevention of stray light and scattering.

[0151] The black quartz glass of the present invention can be suitably used as a material for components (e.g., optical cells, light-shielding members, infrared-absorbing members, and heat-storing members) for various products (e.g., optical analysis equipment, semiconductor manufacturing equipment, and infrared heating equipment). In particular, the black quartz glass of the present invention is useful as an optical cell, light-shielding member, infrared-absorbing member, or heat-storing member in the fields of optical analysis, semiconductor manufacturing, or infrared heating.

Claims

1. Black quartz glass containing 0.5 to 10 parts by mass of Si and 0 to 5 parts by mass of SiO per 100 parts by mass of silica, wherein the glass structure is substantially free of pores, and the number of pores with a diameter of 30 μm or more is 5 / mm in a microscopic image of a cross section of the glass structure. ２ and the SCE reflectance in the wavelength range of 350 nm to 750 nm is 10% or less.

2. The black quartz glass of claim 1, having a water absorption rate of 0.1% or less.

3. The black quartz glass according to claim 1 or 2, which has a density whose difference in density compared to the theoretical density is 1% or less in absolute value.

4. L ＊ a ＊ b ＊ In the color system, the lightness L is 30 or less ＊ , saturation a below 3.5 ＊ and saturation b less than 4 ＊ The black quartz glass according to claim 1 or 2, having an absolute value of 5. The black quartz glass according to claim 1 or 2, wherein the content of each of the metal impurities in the black quartz glass is 1 ppm or less.

6. The black quartz glass according to claim 1 or 2, which satisfies one or more of the following (a) to (i): (a) the black quartz glass has a viscosity of 2.19 to 2.30 g / cm ３ (b) the black quartz glass has a specific heat of 1090 to 1130 J / kg·K at a temperature of 500°C; (c) the black quartz glass has a specific heat of 7×10 －７ ~8 x 10 －７ m ２ / s; (d) the black quartz glass has a thermal conductivity of 1.5 to 2.1 W / mK at a temperature of 500°C; (e) the black quartz glass has a thermal diffusivity of 2 x 10 in the range of 30°C to 600°C. －７ ~12 x 10 －７ / °C, (f) the black quartz glass has a thickness of 1 mm and an optical transmittance of 0.5% or less at wavelengths of 200 to 3000 nm, (g) in a machining test of the black quartz glass, the number of chips with a maximum length of 0.5 mm or more occurring is 1 / 100 cm ２ and the number of discolored areas with a maximum length of 1 mm or more is 1 per 100 cm ２ Here, the machining test is carried out by polishing the surface of the black quartz glass to a roughness Ra of 0.8 μm. (h) In a heating test of the black quartz glass, the number of bubbles having a maximum length of 1 mm or more is 1 / 100 cm. ２ and the number of discolored areas with a maximum length of 1 mm or more is 1 per 100 cm ２ Here, the heating test is carried out by heating the black quartz glass at 1370°C for 3 hours. (i) In the quenching / thermal shock test of the black quartz glass, the number of chips with a maximum length of 0.5 mm or more is 1 / 100 cm ２ The quenching / thermal shock test is carried out by polishing both surfaces of a test piece measuring 75 mm square and 10 mm thick to a roughness Ra of 0.8 μm, heating the polished test piece at 900° C. for 30 minutes, and then immersing it in water at room temperature.

7. The silica portion in the glass structure is 10 to 40 mass% of fumed silica and 0.05 to 3.0 μm D based on the total mass of the silica portion. ５０ 10 to 40 mass% of a first spherical silica having a D of 0.25 to 15 μm ５０ The remaining second spherical silica has a D ５０ is the D of the first spherical silica ５０ The black quartz glass according to claim 1 or 2, wherein the black quartz glass has a refractive index of 5 times or more.

8. The first spherical silica is D of the first spherical silica ５０ D of 1 / 5 or more １０ and D ５０ D less than 10 times ９０ The second spherical silica has a D of the second spherical silica. ５０ D of 1 / 5 or more １０ and D ５０ D less than 10 times ９０ The black quartz glass according to claim 7, having 9. At least a part of the Si in the glass structure exists as Si particles, and the Si particles are D ５０ The black quartz glass according to claim 1 or 2, having a particle size distribution of 5 to 10 μm.

10. At least a part of the SiO in the glass structure exists as SiO particles, and the SiO particles are D ５０ The black quartz glass according to claim 1 or 2, having a particle size distribution of 3 to 15 μm.

11. A method for producing the black quartz glass of claim 1, comprising: mixing and consolidating Si powder and silica powder to which SiO powder has been added, or silica powder to which Si powder has been added; pressurizing the powder obtained by mixing and consolidating to produce a pressed compact; and sintering the pressed compact in air at a maximum temperature of 1300 to 1400°C to obtain black quartz glass, wherein the amount of Si powder added is 0.5 to 10 parts by mass per 100 parts by mass of silica powder; the amount of SiO powder added is 0 to 5 parts by mass per 100 parts by mass of silica powder; and the silica powder is a mixture of 10 to 40% by mass of fumed silica and 0.05 to 3.0 μm D based on the total mass of the silica powder. ５０ 10 to 40 mass% of a first spherical silica having a D of 0.25 to 15 μm ５０ and the remaining second spherical silica having D ５０ is the D of the first spherical silica ５０ This is more than five times the amount.

12. The first spherical silica is D of the first spherical silica ５０ D of 1 / 5 or more １０ and D ５０ D less than 10 times ９０ The second spherical silica has a D of the second spherical silica. ５０ D of 1 / 5 or more １０ and D ５０ D less than 10 times ９０ The method of claim 11 , comprising:

13. Si powder is D ５０ The method according to claim 11 or 12, wherein the particle size distribution is 5 to 10 μm.

14. SiO powder is D ５０ The method according to claim 11 or 12, wherein the particle size distribution is 3 to 15 μm.

15. The method of claim 11 or 12, wherein the silica powder contains one or more types of spherical silica having different particle sizes other than the first and second spherical silica.

16. The method of claim 11 or 12, wherein sintering is carried out for 0.5 to 5 hours.

17. The manufacturing method according to claim 11 or 12, wherein the fumed silica satisfies one or more of the following (i) to (iv): (i) the fumed silica has a density of 0.03 to 0.08 g / cm ３ (ii) the fumed silica has a tapped bulk density of 50 to 100 m ２ / g, (iii) the fumed silica has an OH group concentration of 0.5 to 1.0 mass %, and (iv) the content of metal impurities in the fumed silica is 1 ppm or less.

18. The method according to claim 11 or 12, wherein the co-consolidation is carried out so that the tapped bulk density of the powder obtained by co-consolidation is 5 to 20 times the tapped bulk density of the fumed silica.

19. A black quartz glass member manufactured from the black quartz glass according to claim 1 or 2.

20. The black quartz glass member according to claim 19, which is an optical component, a light-shielding component, an infrared absorbing component, or a heat storage component.

21. The black quartz glass member according to claim 20, which is an optical component such as a spectroscopic cell, a projector reflector, or an optical fiber connector, or a light-shielding member for semiconductor manufacturing equipment or infrared heating equipment.

22. An article of manufacture comprising the black quartz glass member of claim 19.

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