摘要:
A process for producing a transparent or opaque silica glass product including mixing a silica fine powder and a cellulose derivative and injection molding the mixture, followed by degreasing treatment and baking treatment, which is characterized in that the cellulose derivative is a cellulose derivative which causes reversible thermal gelation in an aqueous solution of at least one member selected from methyl cellulose, hydroxypropylmethyl cellulose and hydroxyethylmethyl cellulose; in producing a transparent silica glass product, the cellulose derivative is added in water heated at a gelation temperature thereof or higher, and after cooling, the formed aqueous solution is kneaded with the silica fine powder; and in producing an opaque silica glass product, the cellulose derivative is added in a silica slurry containing a silica powder and heated at a gelation temperature of the cellulose derivative or higher.
摘要:
The invention relates to a method for the economic production of a blank for a component made from laser-active quartz glass in any form or dimension. The method comprises the following method steps: a) preparation of a dispersion with a solids content of at least 40 wt. %, comprising SiO2 nanopowder and doping agents, including a cation of the rare earth metals and transition metals in a fluid, b) granulation by agitation of the dispersion, with removal of moisture to form a doped SiO2 granulate of spherical porous granular particles with a moisture content of less than 35 wt. % and a density of at least 0.95 g/cm3, c) drying and purification of the SiO2 granulate, by heating to a temperature of at least 1000° C. to form doped porous SiO2 grains with an OH content of less than 10 ppm and d) sintering or fusing the doped SiO2 grains in a reducing atmosphere to give the blank made from doped quartz glass.
摘要:
What is disclosed includes OD-doped synthetic silica glass capable of being used in optical elements for use in lithography below about 300 nm. OD-doped synthetic silica glass was found to have significantly lower polarization-induced birefringence value than non-OD-doped silica glass with comparable concentration of OH. Also disclosed are processes for making OD-doped synthetic silica glasses, optical member comprising such glasses, and lithographic systems comprising such optical member. The glass is particularly suitable for immersion lithographic systems due to the exceptionally low polarization-induced birefringence values at about 193 nm.
摘要:
A method for the production of a homogenous, shaped SiO2 body of near net shape wherein amorphous SiO2 particles comprising relatively large amorphous SiO2 particles and relatively small amorphous SiO2 particles are electrophoretically deposited from an aqueous dispersion on an electrically nonconductive membrane, the shape and geometry of which correspond to the shaped SiO2 body to be produced, wherein the membrane has an average pore size which is larger than the average particle size of the smaller amorphous SiO2 particles.
摘要:
The invention relates to a method for producing porous SiO2 green bodies having an extremely high green density, or porous SiO2 green bodies having an internal density gradient which is adjusted in a targeted manner. The inventive method is characterised in that a porous SiO2 green body known per se and consisting of amorphous SiO2 is redensified by electrophoretically depositing SiO2 particles in the pores of the green body.
摘要:
A number of unique processes are disclosed for manufacture of sintered high-purity quartz glass products in which a shaped silica body or preform is made from an aqueous slurry of micronized silica particles by gel casting, slip casting or electrophoretic deposition. The silica particles may comprise a major portion by weight of crystalline silica. In one embodiment of the invention the sintered quartz glass is transparent, substantially bubble-free and suitable for scientific or optical uses. In another embodiment the porous silica preform is fired in steam to increase the hydroxyl content and then nitrided in a nitrogen-hydrogen reducing atmosphere. A minute amount of chemically-combined nitrogen in the high-purity quartz glass is sufficient to provide a tremendous improvement in physical properties and an incredible increase in the resistance to devitrification.
摘要:
The invention relates to fused silica having low compaction under high energy irradiation, particularly adaptable for use in photolithography applications.
摘要:
Molded bodies of quartz glass have at least one surface area of transparent quartz glass, the exposed surfaces of which are smooth and which have a surface microroughness of less than 8 .mu.m. The base material has a chemical purity of at least 99.9% and a cristobalite content of no more than 1%; is gas-impermeable and opaque; and contains pores. At a wall thickness of 1 mm, the base material has a nearly uniform direct spectral transmission of less than 10% in the wavelength range of .lambda.=190-2,650 nm; and which has a density of at least 2.215 g/cm.sup.3. The transparent surface area is formed from base material by heating it to a temperature above 1,650.degree. C. The thickness of the transparent layer is at least 0.5 mm, and its direct spectral transmission in the wavelength range of .lambda.=6001-2,650 nm is at least 60% for a layer thickness of 1 mm.
摘要:
This invention is directed to the production of essentially defect-free high purity fused silica glass articles, the method comprising the following steps: (a) forming a green body from silica particulates or a porous body of amorphous silica; (b) sintering said body in a chamber by raising the temperature of the chamber to above 1720.degree. C., while purging the chamber with helium or applying a vacuum to the chamber; and (c) consolidating the sintered body in a chamber by raising the temperature within the chamber to at least 1750.degree. C., introducing an inert gas into the chamber at a pressure less than about 6.9 MPa (1000 psig), and cooling the chamber while maintaining the pressurized atmosphere to a temperature at least below the annealing point of the glass. In the most preferred practice, a green body of silica particulates will be prepared via a sol-gel process.
摘要:
The invention relates especially to a mixture of grains and particles of fused vitreous silica produced by dry mixing: (i) a moderately coarse particle size fraction of fused vitreous silica, (ii) a fine particle size fraction of fused vitreous silica, in which at least 95% by weight of the grains are smaller than 40 .mu.m, (iii) substantially spherical particles of fume silica, and (iv) optionally, at least one particle size fraction of fused vitreous silica which is coarser than fraction (i), the constituents (i) to (iv) being employed in the following proportions by weight: (i) 15-70%, (ii) 15-55%, (iii) 3-15% and (iv) 0-52%. The mixture can be used for the production of articles made of sintered vitreous silica.