Black Quartz Glass and Method for Manufacturing Same

Abstract

The present invention relates to a black quartz glass comprising Si of 0.5 to 10 mass %, SiO of 0.1 to 5 mass % and SiO.sub.2 of the residue, wherein the SCE reflectance at a wavelength of 350 nm to 750 nm is 10% or less; a method for producing the black quartz glass, comprising: pressure-molding a powder obtained by mixing and consolidating (1) fumed silica, or (2) a mixture powder of fumed silica and a synthetic silica powder, or (3) a mixture powder of fumed silica, spherical silica and a synthetic silica powder, with a Si powder of 0.5 to 10 mass % and a SiO powder of 0.1 to 5 mass %, and heating and sintering the pressure-molded product in the atmosphere; and a product comprising a black quartz glass member made of the black quartz glass. The present invention allows to provide a black quartz glass which has an excellent light-shielding property, has no risk of causing contamination in a step of using it, has sufficient color uniformity when the size is enlarged, and is capable of producing a large ingot, and to provide a method for producing the black quartz glass with excellent productivity even in the large ingot, and to provide a black quartz glass product made of the black quartz glass.

Claims

1. A black quartz glass comprising 0.5 to 10 mass % of Si, 0.1 to 5 mass % of SiO and a residue being SiO.sub.2, wherein the SCE reflectance at a wavelength of 350 nm to 750 nm is 10% or less.

2. The black quartz glass according to claim 1, wherein the brightness L is 30 or less, the absolute value of the saturation a is 3.5 or less, and the absolute value of b* is 4 or less in L*a*b* color system.

3. The black quartz glass according to claim 1, wherein each content of metallic impurities other than elemental Si is 1 ppm or less.

4. The black quartz glass according to claim 1, which satisfies any one or more of the following physical properties (a) to (f): (a) the density is 2.15 g/cm.sup.3 or more and 2.3 g/cm.sup.3 or less, (b) the specific heat at a temperature of 500 C. is 1090 J/kg.Math.K or more and 1130 J/kg.Math.K or less, (c) the thermal diffusivity at a temperature of 500 C. is 710.sup.7 m.sup.2/s or more and 810.sup.7 m.sup.2/s or less, (d) the thermal conductivity at a temperature of 500 C. is 1.5 W/mK or more and 2.1 W/mK or less, (e) the thermal expansion coefficient in the range of 30 C. to 600 C. is 210.sup.7/ C. or more and 1210.sup.7/ C. or less, (f) the optical transmittance at a wavelength of 200 nm to 3000 nm with a thickness of 1 mm is 0.5% or less.

5. The black quartz glass according to claim 1, wherein at least a part of the Si contained in the quartz glass is particulate, and the particulate has a D.sub.50 of 5 to 10 m, a D.sub.10 of 1 m or more and a D.sub.95 of 30 m or less in a particle diameter.

6. The black quartz glass according to claim 1, wherein at least a part of the SiO contained in the quartz glass is particulate, and the particulate has a D.sub.50 of 5 to 15 m, a D.sub.10 of 1 m or more and a D.sub.90 of 35 m or less in a particle diameter.

7. The black quartz glass according to claim 1, wherein (a) the SiO.sub.2 part is a sintered body of fumed silica; or (b) the SiO.sub.2 part is a sintered body comprising fumed silica of 30 to 60 mass % and a synthetic silica powder of the residue having a D.sub.50 of 60 to 100 m, a D.sub.10 of 40 m or more and a D.sub.95 of 180 m or less in a particle diameter; or (c) the SiO.sub.2 part is a sintered body comprising 30 to 60 mass % of fumed silica 5 to 25 mass % of spherical silica having a D.sub.50 of 5 to 15 m, a D.sub.10 of 1 m or more and a D.sub.95 of 70 m or less, and a synthetic silica powder of the residue having a D.sub.50 of 60 to 100 m, a D.sub.10 of 40 m or more and a D.sub.95 of 180 m or less in a particle diameter.

8. A method for producing black quartz glass, comprising: (1) pressure-molding a powder obtained by mixing and consolidating fumed silica with 0.5 to 10 mass % Si powder and 0.1 to 5 mass % of SiO powder, heating the pressure-molded product in atmosphere at a maximum temperature of 1200 to 1300 C. and sintering the fumed silica to obtain the black quartz glass according to claim 1 or the black quartz glass according to claim 1 wherein the SiO.sub.2 part is a sintered body of fumed silica; or (2) pressure-molding a powder obtained by mixing and consolidating 30 to 60 mass % of fumed silica and a synthetic silica powder of the residue of claim 1 having a D.sub.50 of 60 to 100 m, a D.sub.10 of 40 m or more and a D.sub.95 of 180 m or less in a particle diameter, with 0.5 to 10 mass % of a Si powder and 0.1 to 5 mass % of SiO powder to provide a pressure-molded product, heating and sintering the pressure-molded product in the atmosphere at a maximum temperature of 1250 to 1320 C. to obtain the black quartz glass according to claim 1 or the black quartz glass according to claim 1 wherein the SiO.sub.2 part is a sintered body comprising fumed silica of 30 to 60 mass % and a synthetic silica powder of the residue having a D.sub.50 of 60 to 100 m a D.sub.10 of 40 m or more and a D.sub.95 of 180 m or less in a particle diameter; or (3) pressure-molding a powder obtained by mixing and consolidating 30 to 60 mass % of fumed silica, 5 to 25 mass % of spherical silica having a D.sub.50 of 5 to 15 m, a D.sub.10 of 1 m or more and a D.sub.95 of 70 m or less, and a synthetic silica powder of the residue of claim 1 having a D.sub.50 of 60 to 100 m, a D.sub.10 of 40 m or more and a D.sub.95 of 180 m or less in a particle diameter, with 0.5 to 10 mass % of a Si powder and 0.1 to 5 mass % of a SiO powder to provide a pressure-molded product, heating and sintering the pressure-molded product in atmosphere at a maximum temperature of 1250 to 1320 C. to obtain the black quartz glass according to claim 1 or the black quartz glass according claim 1 wherein the SiO.sub.2 part is a sintered body comprising 30 to 60 mass % of fumed silica, 5 to 25 mass % of spherical silica having a D.sub.50 of 5 to 15 m, a D.sub.10 of 1 m or more and a D.sub.95 of 70 m or less, and a synthetic silica powder of the residue having a D.sub.50 of 60 to 100 m, a D.sub.10 of 40 m or more and a D.sub.95 of 180 M or less in a particle diameter.

9. The method for producing black quartz glass according to claim 8, wherein the fumed silica satisfies at least one of: the tapped bulk density is 0.03 to 0.08 g/cm.sup.3, the BET specific surface area is 50 to 100 m.sup.2/g, the OH group-concentration is 0.5 to 1.0 mass %, and each content of metallic impurities other than Si is 1 ppm or less.

10. The method for producing black quartz glass according to claim 8, wherein the Si powder has a D.sub.50 of 5 to 10 m, a D.sub.10 of 1 m or more and a D.sub.95 of 30 m or less in a particle diameter, and the SiO powder has a D.sub.50 of 3 to 15 m, a D.sub.10 of 1 m or more and a D.sub.90 of 35 m or less in a particle diameter.

11. The method for producing black quartz glass according to claim 8, wherein the mixing and consolidation are performed so that the tapped bulk density of the powder obtained by the mixing and consolidation is 5 to 20 times the tapped bulk density of the fumed silica.

12. The method for producing black quartz glass according to claim 8 wherein the heating and sintering time in the atmosphere is carried out for 0.5 to 5 hours.

13. A product comprising a black quartz glass member made of the black quartz glass according to claim 1.

14. The product according to claim 13, wherein the black quartz glass member is an optical component, a light-shielding member or an infrared heat absorption/storage member.

15. The product according to claim 14, wherein the optical component is a spectroscopic cell, a reflector for projectors or a connector for optical fibers, and the light-shielding member is a light-shielding member for semiconductor manufacturing apparatuses or for infrared heating apparatuses.

16. The black quartz glass according to claim 2, wherein each content of metallic impurities other than elemental Si is 1 ppm or less.

17. The black quartz glass according to claim 16, which satisfies any one or more of the following physical properties (a) to (f): (a) the density is 2.15 g/cm.sup.3 or more and 2.3 g/cm.sup.3 or less, (b) the specific heat at a temperature of 500 C. is 1090 J/kg.Math.K or more and 1130 J/kg.Math.K or less, (c) the thermal diffusivity at a temperature of 500 C. is 710.sup.7 m.sup.2/s or more and 810.sup.7 m.sup.2/s or less, (d) the thermal conductivity at a temperature of 500 C. is 1.5 W/mK or more and 2.1 W/mK or less, (e) the thermal expansion coefficient in the range of 30 C. to 600 C. is 210.sup.7/ C. or more and 1210.sup.7/ C. or less, (f) the optical transmittance at a wavelength of 200 nm to 3000 nm with a thickness of 1 mm is 0.5% or less.

18. The black quartz glass according to claim 17, wherein at least a part of the Si contained in the quartz glass is particulate, and the particulate has a D.sub.50 of 5 to 10 m, a D.sub.10 of 1 m or more and a D.sub.95 of 30 m or less in a particle diameter.

19. The black quartz glass according to claim 18, wherein at least a part of the SiO contained in the quartz glass is particulate, and the particulate has a D.sub.50 of 5 to 15 m, a D.sub.10 of 1 m or more and a D.sub.90 of 35 m or less in a particle diameter.

20. The black quartz glass according to claim 19, wherein (a) the SiO.sub.2 part is a sintered body of fumed silica; or (b) the SiO.sub.2 part is a sintered body comprising fumed silica of 30 to 60 mass % and a synthetic silica powder of the residue having a D.sub.50 of 60 to 100 m, a D.sub.10 of 40 m or more and a D.sub.95 of 180 m or less in a particle diameter; or (c) the SiO.sub.2 part is a sintered body comprising 30 to 60 mass % of fumed silica, 5 to 25 mass % of spherical silica having a D.sub.50 of 5 to 15 m, a D.sub.10 of 1 m or more and a D.sub.95 of 70 m or less, and a synthetic silica powder of the residue having a D.sub.50 of 60 to 100 m, a D.sub.10 of 40 m or more and a D.sub.95 of 180 m or less in a particle diameter.

Description

EXAMPLES

[0085] Hereinafter, the present invention will be described in detail with Examples, but the present invention is not limited to the Examples.

[0086] Sample characteristics were measured as follows. [0087] (1) The density of the sintered body was measured by the Archimedes method. [0088] (2) The SCE reflectance was measured for samples processed into a thickness of 7 mm, with a spectrocolorimeter, according to JIS Z 8722. The highest value in the wavelength range of 360 to 740 nm range is described. [0089] (3) The brightness L* and the saturation a*, b* in Lab color system were measured with a spectrocolorimeter, according to JIS Z 8722. [0090] (4) The specific heat was measured by a differential scanning calorimetry (DSC method) at a temperature of 500 C. for samples processed into 61 mint. [0091] (5) Thermal diffusivity was measured by a flushing method at a temperature of 500 C. for samples processed into 101 mint, according to JISR1611. [0092] (6) The thermal conductivity was calculated by the following equation under the condition of a temperature of 500 C.

Thermal conductivity=specific heatthermal diffusivitydensity of sintered body [0093] (7) The thermal expansion coefficient was measured by thermomechanical analysis (TMA method) at 30 to 600 C. for samples processed into 3420 mmL. [0094] (8) The optical transmittance was measured using a spectrophotometer in the range of 200 to 3000 nm for samples processed into a thickness of 1 mm.

Example 1

[0095] To fumed silica was added with a Si powder of 2.0 mass % and a SiO powder of 0.5 mass %, wherein the fumed silica had the tapped bulk density of 0.06 g/cm.sup.3, the BET specific surface area of 85 m.sup.2/g, the OH group-concentration of 0.7 mass % and each content of metallic impurities other than Si of 1 ppm or less, the Si powder had D.sub.50 of 7 m, D.sub.10 of 4 m and D.sub.95 of 11 m in the particle diameter, and the SiO powder had D.sub.50 of 10 m, D.sub.10 of 5 m and D.sub.90 of 20 m in the particle diameter, and then the mixing and consolidation were performed in a ball mill without solvents. The obtained powder for pressure-molding with the tapped bulk density of 0.45 g/cm.sup.3 was pressure-molded in 90 Mpa, and sintered in the atmosphere at 1250 C. for 3 hours.

[0096] The obtained black quartz glass had the density of 2.20 g/cm.sup.3, the SCE reflectance of 5.3% or less, the brightness L* of 20.6 and the saturation a* of 1.9 and b* of 0.6 in L*a*b color system, the specific heat at a temperature of 500 C. is 1103 J/kg.Math.K, the thermal diffusivity at a temperature of 500 C. is 7.510.sup.7 m.sup.2/s, the thermal conductivity at a temperature of 500 C. is 1.82 W/mK, the thermal expansion coefficient at a temperature of 30 to 600 C. is 9.410.sup.7/ C., and the optical transmittance in the range of 200 to 3000 nm of 0.12% or less. The obtained black quartz glass has no color unevenness, and exhibits a sufficient black-based color that does not generate light transmission, stray light and light scattering, and was confirmed to be visually homogeneous and aesthetically excellent.

Example 2

[0097] To fumed silica was added with a Si powder of 1.0 mass % and a SiO powder of 1.0 mass %, wherein the fumed silica had the tapped bulk density of 0.06 g/cm.sup.3, the BET specific surface area of 85 m.sup.2/g, the OH group-concentration of 0.7 mass % and each content of metallic impurities other than Si of 1 ppm or less, the Si powder had D.sub.50 of 8 m, D.sub.10 of 3 m and D.sub.95 of 20 m in the particle diameter, and the SiO powder had D.sub.50 of 10 m, D.sub.10 of 5 m and D.sub.90 of 20 m in the particle diameter, and then the mixing and consolidation were performed in a ball mill without solvents. The obtained powder for pressure-molding with the tapped bulk density of 0.45 g/cm.sup.3 was pressure-molded in 90 Mpa, and sintered in the atmosphere at 1250 C. for 3 hours.

[0098] The obtained black quartz glass had the density of 2.19 g/cm.sup.3, the SCE reflectance of 7.6% or less, the brightness L* of 25.2 and the saturation a* of 2.6 and b* of 3.3 in L*a*b* color system, the specific heat at a temperature of 500 C. of 1108 J/kg.Math.K, the thermal diffusivity at a temperature of 500 C. of 7.510.sup.7 m.sup.2/s, the thermal conductivity at a temperature of 500 C. of 1.83 W/mK, the thermal expansion coefficient at a temperature of 30 to 600 C. of 8.310.sup.7/ C., and the optical transmittance in the range of 200 to 3000 nm of 0.17% or less. The obtained black quartz glass has no color unevenness, and exhibits a sufficient black-based color that does not generate light transmission, stray light and light scattering, and was confirmed to be visually homogeneous and aesthetically excellent.

Example 3

[0099] To a silica mixed powder comprising fumed silica of 50 mass % and a synthetic silica powder of 50 mass % was added with a Si powder of 2.0 mass % and a SiO powder of 0.5 mass %, wherein the fumed silica had the tapped bulk density of 0.06 g/cm.sup.3, the BET specific surface area of 85 m.sup.2/g, the OH group-concentration of 0.7 mass % and each content of metallic impurities other than Si of 1 ppm or less, the synthetic silica powder had D.sub.50 of 80 m, D.sub.10 of 48 m, D.sub.95 of 160 m in the particle diameter and each content of metallic impurities other than Si of 1 ppm or less, the Si powder had D.sub.50 of 6 m, D.sub.10 of 4 m and D.sub.95 of 10 m in the particle diameter, and the SiO powder had D.sub.50 of 10 m, D.sub.10 of 5 m and D.sub.90 of 20 m in the particle diameter, and then the mixing and consolidation were performed in a ball mill without solvents. The obtained powder for pressure-molding with the tapped bulk density of 0.60 g/cm.sup.3 was pressure-molded in 90 Mpa, and sintered in the atmosphere at 1300 C. for 3 hours.

[0100] The obtained black quartz glass had the density of 2.20 g/cm.sup.3, the SCE reflectance of 5.3% or less, the brightness L of 18.2 and the saturation a* of 3.2 and b* of 2.1 in L*a*b* color system, the specific heat at a temperature of 500 C. of 1105 J/kg.Math.K, the thermal diffusivity at a temperature of 500 C. of 7.510.sup.7 m.sup.2/s, the thermal conductivity at a temperature of 500 C. of 1.81 W/mK, the thermal expansion coefficient at a temperature of 30 to 600 C. of 9.010.sup.7/ C., and the optical transmittance in the range of 200 to 3000 nm of 0.14% or less. The obtained black quartz glass has no color unevenness, and exhibits a sufficient black-based color that does not generate light transmission, stray light and light scattering, and was confirmed to be visually homogeneous and aesthetically excellent.

Example 4

[0101] To a silica mixed powder comprising fumed silica of 40 mass %, a synthetic silica powder of 42 mass % and spherical silica of 18 mass % was added with a Si powder of 1.0 mass % and a SiO powder of 0.5 mass %, wherein the fumed silica had the tapped bulk density of 0.06 g/cm.sup.3, the BET specific surface area of 85 m.sup.2/g, the OH group-concentration of 0.7 mass % and each content of metallic impurities other than Si of 1 ppm or less, the synthetic silica powder had D.sub.50 of 80 m, D.sub.10 of 48 m, D.sub.95 of 160 m in the particle diameter and each content of metallic impurities other than Si of 1 ppm or less, the spherical silica had D.sub.50 of 11 m, D.sub.10 of 3 m, D.sub.95 of 52 m in the particle diameter and each content of metallic impurities other than Si of 1 ppm or less, the Si powder had D.sub.50 of 6 m, D.sub.10 of 3 m and D.sub.95 of 13 m in the particle diameter, and the SiO powder had D.sub.50 of 5 m, D.sub.10 of 2 m and D.sub.90 of 9 m in the particle diameter, and then the mixing and consolidation were performed in a ball mill without solvents. The obtained powder for pressure-molding with the tapped bulk density of 0.79 g/cm.sup.3 was pressure-molded in 90 Mpa, and sintered in the atmosphere at 1300 C. for 3 hours.

[0102] The obtained black quartz glass had the density of 2.20 g/cm.sup.3, the SCE reflectance of 5.2% or less, the brightness L* of 19.0 and the saturation a* of 2.2 and b* of 3.6 in L*a*b* color system, the specific heat at a temperature of 500 C. of 1112 J/kg.Math.K, the thermal diffusivity at a temperature of 500 C. of 7.510.sup.7 m.sup.2/s, the thermal conductivity at a temperature of 500 C. of 1.83 W/mK, the thermal expansion coefficient at a temperature of 30 to 600 C. of 7.610.sup.7/ C., and the optical transmittance in the range of 200 to 3000 nm of 0.22% or less. The obtained black quartz glass has no color unevenness, and exhibits a sufficient black-based color that does not generate light transmission, stray light and light scattering, and was confirmed to be visually homogeneous and aesthetically excellent.

Comparative Example 1

[0103] To fumed silica was added with a Si powder of 0.5 mass %, wherein the fumed silica had the tapped bulk density of 0.06 g/cm.sup.3, the BET specific surface area of 85 m.sup.2/g, the OH group-concentration of 0.7 mass % and each content of metallic impurities other than Si of 1 ppm or less, the Si powder had D.sub.50 of 7 m, D.sub.10 of 4 m and D.sub.95 of 11 m in the particle diameter, and then the mixing and consolidation were performed in a ball mill without solvents. The powder for pressure-molding was pressure-molded in 90 Mpa, and sintered in the atmosphere at 1250 C. for 3 hours.

[0104] The obtained black quartz glass had a small density of 2.09 g/cm.sup.3, a large SCE reflectance of 13.0% or less, a large brightness L* of 36.2 and the saturation a* of 1.1 and b* of 1.7 in L*a*b* color system. Its color had unevenness, and it was insufficient for prevention of light transmission, stray light and light scattering.

TABLE-US-00001 TABLE 1 Density g/cm.sup.3 SCE reflectance L* a* b* Example 1 2.20 5.3% or less 20.6 1.9 0.6 Example 2 2.19 7.6% or less 25.2 2.6 3.3 Example 3 2.20 5.3% or less 18.2 3.2 2.1 Example 4 2.20 5.2% or less 19.0 2.2 3.6 Comparative 2.09 13.0% or less 36.2 1.1 1.7 Example 1

TABLE-US-00002 TABLE 2 Thermal Optical Specific Thermal Thermal expansion trans- heat diffusivity conductivity coefficient mittance J/kg .Math. K m.sup.2/s W/mK 10.sup.7/ C. % Example 1103 7.5 10.sup.7 1.82 9.4 0.12 1 Example 1108 7.5 10.sup.7 1.83 8.3 0.17 2 Example 1105 7.5 10.sup.7 1.82 9.0 0.13 3 Example 1112 7.5 10.sup.7 1.83 7.6 0.22 4

INDUSTRIAL APPLICABILITY

[0105] The present invention is useful in the field of black quartz glass. The present invention allows to economically and efficiently provide a large black quartz glass ingot having an excellent light-shielding property. The black quartz glass of the present invention is suitably used for the quartz glass cell for optical analysis and used for the light-shielding member or the infrared heat absorption/storage member for semiconductor manufacturing apparatuses or for infrared heating apparatuses.