Abstract: Methods for producing a quartz glass component with reflector layer are known in which a reflector layer composed of quartz glass acting as a diffuse reflector is produced on at least part of the surface of a substrate body composed of quartz glass. In order, taking this as a departure point, to specify a method which enables cost-effective and reproducible production of uniform SiO2 reflector layers on quartz glass components, it is proposed according to the invention that the reflector layer is produced by thermal spraying by means of SiO2 particles being fed to an energy carrier, being incipiently melted or melted by means of said energy carrier and being deposited on the substrate body. In the case of a quartz glass component obtained according to the method, the SiO2 reflector layer is formed as a layer which is produced by thermal spraying and has an opaque effect and which is distinguished by freedom from cracks and uniformity.

Abstract: In a known method for bonding components made of material with a high silicic acid content by means of a substance to substance bond, a SiO2-containing bonding mass is formed between connecting surfaces of the components. In order to provide for cost-efficient manufacture of a thermally stable composite, the invention proposes to generate a SiO2-containing bonding mass that is generic with regard to the material with a high silicic acid content, comprising the following procedural steps: provision of a slurry containing amorphous SiO2 particles; formation of a slurry mass between the connecting surfaces which are fixed in position with regard to each other; drying of the slurry mass; and solidification of the slurry mass by heating under formation of the SiO2-containing bonding mass. A component assembly manufactured according to the method of the invention shows high temperature resistance and thermal fatigue resistance and can also be used in contamination-sensitive applications.

Abstract: Methods for producing a quartz glass component with reflector layer are known in which a reflector layer composed of quartz glass acting as a diffuse reflector is produced on at least part of the surface of a substrate body composed of quartz glass. In order, taking this as a departure point, to specify a method which enables cost-effective and reproducible production of uniform SiO2 reflector layers on quartz glass components, it is proposed according to the invention that the reflector layer is produced by thermal spraying by means of SiO2 particles being fed to an energy carrier, being incipiently melted or melted by means of said energy carrier and being deposited on the substrate body. In the case of a quartz glass component obtained according to the method, the SiO2 reflector layer is formed as a layer which is produced by thermal spraying and has an opaque effect and which is distinguished by freedom from cracks and uniformity.

Abstract: In a known method for drawing a tubular quartz glass strand, a crucible is fed with SiO2-containing start material, the start material is softened in the crucible and, as a softened quartz glass mass, is drawn vertically downwards as a tubular quartz glass strand along a drawing axis through an annular gap between an outer member and an inner member, which is arranged in a through hole of the outer member, of a drawing nozzle provided in the bottom area of the crucible.

Abstract: In a known method for bonding components made of material with a high silicic acid content by means of a substance to substance bond, a SiO2-containing bonding mass is formed between connecting surfaces of the components. In order to provide for cost-efficient manufacture of a thermally stable composite, the invention proposes to generate a SiO2-containing bonding mass that is generic with regard to the material with a high silicic acid content, comprising the following procedural steps: provision of a slurry containing amorphous SiO2 particles; formation of a slurry mass between the connecting surfaces which are fixed in position with regard to each other; drying of the slurry mass; and solidification of the slurry mass by heating under formation of the SiO2-containing bonding mass. A component assembly manufactured according to the method of the invention shows high temperature resistance and thermal fatigue resistance and can also be used in contamination-sensitive applications.

Abstract: Disclosed is a component made of quartz glass, especially a crucible. A blank is provided with a stabilizing layer exhibiting a higher softening temperature than quartz glass. In order to provide a quartz glass component which is characterized by high mechanical and thermal resistance, in addition to providing a simple, cost-effective method for the production of said component, the chemical composition of the stabilizing layer (3; 6; 7; 38) is different from that of the quartz glass and said layer is applied by means of heat injection. The inventive method is characterized in that a stabilizing layer (3; 6; 7; 38) whose chemical composition is different from that of quartz glass is applied by heat injection.

Abstract: In a process for manufacture of dense, amorphous quartz glass granulate by production of a porous granulate from amorphous SiO2 powder and vitrification of the granulate, a porous SiO2 granulate is exposed to a fuel gas flame and is finely dispersed, heated and vitrified therein. The fuel gas flame is more flexible as concerns adjustment of the temperature than in known processes. It is in particular possible to set higher temperatures. The granulate can be exposed to very high sintering temperatures in the fuel gas flame without sintering into agglomerates. At the same time, heat resistance problems of sintering containers such as furnaces and melting pots are avoided. In addition, contamination of the SiO2 granulate by contact with the walls of sintering or vitrifying containers is eliminated. The process makes it possible to economically produce a highly pure and dense quartz glass granulate.

Abstract: To produce a free-flowing granulate which has a high bulk density and a defined particle size distribution, which generates little dust, is easy to handle, and is suitable as a starting material for quartz glass products, the mixing operation includes a first mixing phase, in which the materials to be mixed are subjected to a slow mixing action to form a coarse-grained mass, and a second mixing phase, in which the coarse-grained mass is converted to a fine-grained mass by a more intensive mixing action which grinds and compacts the grains. The content of silica powder in the materials to be mixed is adjusted at least during the second mixing phase to a value of at least 75 wt. %.

Abstract: In order to provide a temperature- and acid-resistant catalyst carrier based on a gas-pervious carrier body and a porous surface layer having a high silica content, while dispensing with a washcoat, the carrier body and the surface layer are designed as a chemically and physically homogeneous structure shaped in a single operation. The SiO.sub.2 content amounts to at least 99% by weight and has a specific surface from 5 m.sup.2 /g to 50 m.sup.2 /g. In a process for producing a catalyst carrier made of synthetic, amorphous silica particles with more than 99% by weight SiO.sub.2, a paste is prepared with the particles, a liquid, and a binder. Plastifying agents are added to the paste and the paste is continuously extruded into a monolithic greenware strand. The alkali and alkaline earth content of the paste is set at no more than 200 ppm and the greenware is cut to length and sintered at a temperature in a range between 800.degree. C. and 1400.degree. C.