Abstract: A quartz glass body and a process for the preparation of a quartz glass body is disclosed. One process includes providing a silicon dioxide granulate from a pyrogenic silicon dioxide powder, making a glass melt out of the silicon dioxide granulate and making a quartz glass body out of at least part of the glass melt. In at least one process a silicon component different from silicon dioxide is added. A quartz glass body is obtainable by this process. A light guide, an illuminant and a formed body, are each obtainable by further processing of the quartz glass body.

Abstract: Producing a molded body made of opaque quartz glass includes providing SiO2 grains obtained by comminuting quartz glass having a purity of at least 99.9 wt % SiO2, forming a slurry containing a suspension liquid and the SiO2 grains and which has a total solids content, wet grinding the SiO2 grains in the slurry so as to form ground SiO2 grain particles, forming a porous green body from the slurry, and sintering the porous green body. To provide a low cost quartz glass, the wet grinding of the SiO2 grains takes place at least temporarily in the presence of SiO2 nanoparticles, the proportion of which in the total solids content of the slurry is in the range of 0.1 wt % to 10 wt %, and the slurry has a solids content in the range of 76 to 80 wt % after addition of the SiO2 nanoparticles and after the wet grinding.

Abstract: A diffuser material of synthetically produced, pore-containing quartz glass and a method for the manufacture of a molded body consisting fully or in part thereof. The diffuser material has a chemical purity of at least 99.9% SiO2, a cristobalite content of not more than 1%, and a density in the range of 2.0 to 2.18 g/cm3. Starting therefrom, to indicate a diffuser material which is improved with respect to diffuse reflectivity with Lambertian behavior over a wide wavelength range, high material homogeneity and UV radiation resistance, the quartz glass has a hydroxyl group content in the range of at least 200 wt. ppm and at least 80% of the pores have a maximum pore dimension of less than 20 ?m.

Abstract: One aspect relates to a process for the preparation of a quartz glass body. The process includes providing a silicon dioxide granulate from a pyrogenically produced silicon dioxide powder, making a glass melt out of silicon dioxide granulate, and making a quartz glass body out of at least part of the glass melt. The size of the quartz glass body is reduced to obtain a quartz glass grain. The quartz glass body is processed to make a preform and an opaque quartz glass body is made from the preform. One aspect further relates to an opaque quartz glass body which is obtainable by this process. One aspect further relates to a reactor and an arrangement, which are each obtainable by further processing of the opaque quartz glass body.

Abstract: In one method for producing opaque quartz glass, a green body is produced from a slip containing fine, amorphous SiO2 particles and coarse SiO2 reinforcement bodies and the green body is sintered by way of a sintering treatment into a blank made from the opaque quartz glass. The reinforcement bodies with a specific density DK1 are here embedded in a SiO2 matrix with a specific glass density DM. Starting from this, in order to provide a blank of opaque quartz glass that is less susceptible to cracking and illustrates homogeneous transmission even in the case of small wall thicknesses, in one aspect sinterable reinforcement bodies are used, the specific density DK0 of which prior to the sintering treatment is lower than the specific glass density DM, and which due to the sintering treatment reach the specific density DK1 which differs from the specific glass density DM by less than 10%.

Abstract: An infrared emitter is provided. The infrared emitter includes a substrate made of an electrically insulating material. The substrate includes a surface that contacts a printed conductor made of a resistor material that is electrically conducting and generates heat when current flows through it. The electrically insulating material includes an amorphous matrix component into which an additional component is embedded that absorbs in the spectral range of infrared radiation. At least a part of the surface is configured with a cover layer made of porous glass, whereby the printed conductor is embedded, at least in part, in the cover layer.

Abstract: A method for producing a pore-containing opaque quartz glass includes: (a) producing porous SiO2 granulate particles from synthetically produced SiO2, (b) thermally densifying the SiO2 granulate particles to form partly densified SiO2 granulate particles, (c) forming a dispersion from the partly densified SiO2 granulate particles, (d) comminuting the partly densified SiO2 granulate particles to form a slip containing comminuted SiO2 granulate particles, (e) shaping the slip into a shaped body and forming a porous SiO2 green body with a green density rG, and (f) sintering the SiO2 green body into opaque quartz glass. To produce opaque quartz glass that is also suited for the use of spray granulate, during step (b), partly densified SiO2 granulate particles are produced with a specific surface BET-(A) between 0.025 and 2.5 m2/g, and during step (d), comminuted SiO2 granulate particles are produced with a specific surface BET-(B) between 4 and 10 m2/g.

Abstract: A quartz glass body and a process for the preparation of a quartz glass body is disclosed. In one aspect, the process includes providing a silicon dioxide granulate from a pyrogenic silicon dioxide powder, making a glass melt out of the silicon dioxide granulate and making a quartz glass body out of at least part of the glass melt. In at least one process a silicon component different from silicon dioxide is added. One aspect further relates to a quartz glass body which is obtainable by this process. A light guide, an illuminant and a formed body, are each obtainable by further processing of the quartz glass body.

Abstract: One aspect relates to a process for the preparation of a quartz glass body. The process includes providing a silicon dioxide granulate from a pyrogenically produced silicon dioxide powder, making a glass melt out of silicon dioxide granulate, and making a quartz glass body out of at least part of the glass melt. The size of the quartz glass body is reduced to obtain a quartz glass grain. The quartz glass body is processed to make a preform and an opaque quartz glass body is made from the preform. One aspect further relates to an opaque quartz glass body which is obtainable by this process. One aspect further relates to a reactor and an arrangement, which are each obtainable by further processing of the opaque quartz glass body.

Abstract: A diffuser material of synthetically produced, pore-containing quartz glass and a method for the manufacture of a molded body consisting fully or in part thereof. The diffuser material has a chemical purity of at least 99.9% SiO2, a cristobalite content of not more than 1%, and a density in the range of 2.0 to 2.18 g/cm3. Starting therefrom, to indicate a diffuser material which is improved with respect to diffuse reflectivity with Lambertian behavior over a wide wavelength range, high material homogeneity and UV radiation resistance, the quartz glass has a hydroxyl group content in the range of at least 200 wt. ppm and at least 80% of the pores have a maximum pore dimension of less than 20 ?m.

Abstract: An infrared emitter is provided. The infrared emitter includes a substrate made of an electrically insulating material. The substrate includes a surface that contacts a printed conductor made of a resistor material that is electrically conducting and generates heat when current flows through it. The electrically insulating material includes an amorphous matrix component into which an additional component is embedded that absorbs in the spectral range of infrared radiation. At least a part of the surface is configured with a cover layer made of porous glass, whereby the printed conductor is embedded, at least in part, in the cover layer.

Abstract: A low cost method for producing a mechanically and thermally stable composite body containing a first layer of a material with a high silicic acid content and an additional component connected to a second layer of a material with a high silicic acid content and an additional component in a second concentration differing from the first concentration is provided. The method involves (a) preparing a first slurry layer having a free surface using a first shirt mass containing SiO2 particles and an additional component dispersed in a first dispersing agent, (b) providing a second slurry mass containing SiO2 particles and an additional component in a second concentration dispersed in a second dispersing agent, (c) forming a composite-body intermediate product by applying the second slurry mass to the free surface of the first slurry layer, and (d) heating the composite-body intermediate product while forming the composite body.

Abstract: In a known composite material with a fused silica matrix there are regions of silicon-containing phase embedded. In order to provide a composite material which is suitable for producing components for use in high-temperature processes for heat treatment even when exacting requirements are imposed on impermeability to gas and on purity, it is proposed in accordance with the invention that the composite material be impervious to gas, have a closed porosity of less than 0.5% and a specific density of at least 2.19 g/cm3, and at a temperature of 1000° C. have a spectral emissivity of at least 0.7 for wavelengths between 2 and 8 ?m.

Abstract: In one method for producing opaque quartz glass, a green body is produced from a slip containing fine, amorphous SiO2 particles and coarse SiO2 reinforcement bodies and the green body is sintered by way of a sintering treatment into a blank made from the opaque quartz glass. The reinforcement bodies with a specific density DK1 are here embedded in a SiO2 matrix with a specific glass density DM. Starting from this, in order to provide a blank of opaque quartz glass that is less susceptible to cracking and illustrates homogeneous transmission even in the case of small wall thicknesses, in one aspect sinterable reinforcement bodies are used, the specific density DK0 of which prior to the sintering treatment is lower than the specific glass density DM, and which due to the sintering treatment reach the specific density DK1 which differs from the specific glass density DM by less than 10%.

Abstract: In a known composite material with a fused silica matrix there are regions of silicon-containing phase embedded. In order to provide a composite material which is suitable for producing components for use in high-temperature processes for heat treatment even when exacting requirements are imposed on impermeability to gas and on purity, it is proposed in accordance with the invention that the composite material be impervious to gas, have a closed porosity of less than 0.5% and a specific density of at least 2.19 g/cm3, and at a temperature of 1000° C. have a spectral emissivity of at least 0.7 for wavelengths between 2 and 8 ?m.

Abstract: A method for producing a pore-containing opaque quartz glass includes: (a) producing porous SiO2 granulate particles from synthetically produced SiO2, (b) thermally densifying the SiO2 granulate particles to form partly densified SiO2 granulate particles, (c) forming a dispersion from the partly densified SiO2 granulate particles, (d) comminuting the partly densified SiO2 granulate particles to form a slip containing comminuted SiO2 granulate particles, (e) shaping the slip into a shaped body and forming a porous SiO2 green body with a green density rG, and (f) sintering the SiO2 green body into opaque quartz glass. To produce opaque quartz glass that is also suited for the use of spray granulate, during step (b), partly densified SiO2 granulate particles are produced with a specific surface BET-(A) between 0.025 and 2.5 m2/g, and during step (d), comminuted SiO2 granulate particles are produced with a specific surface BET-(B) between 4 and 10 m2/g.

Abstract: A method for producing a solar crucible includes providing a crucible base body of transparent or opaque fused silica having an inner wall, providing a dispersion containing amorphous SiO2 particles, applying a SiO2-containing slip layer to at least a part of the inner wall by using the dispersion, drying the slip layer to form a SiO2-containing grain layer and thermally densifying the SiO2-containing grain layer to form a diffusion barrier layer. The dispersion contains a dispersion liquid and amorphous SiO2 particles that form a coarse fraction and a fine fraction with SiO2 nanoparticles. The weight percentage of the SiO2 nanoparticles based on the solids content of the dispersion is in the range between 2 and 15% by weight. The SiO2-containing grain layer is thermally densified into the diffusion barrier layer through the heating up of the silicon in the crystal growing process.

Abstract: A method for producing a coated component consisting of transparent or opaque fused silica comprises a method step in which a SiO2 granulation layer is applied to a coating surface of a substrate, which in the area of the free surface has a relatively great granulation fine fraction. Starting from this, in order to achieve a smooth, preferably also dense surface layer, it is suggested according to the invention that the application of the SiO2 granulation layer comprises (i) providing a dispersion containing a dispersion liquid and amorphous SiO2 particles which form a coarse fraction with particle sizes ranging between 1 ?m and 50 ?m and a fine fraction of SiO2 nanoparticles having particle sizes of less than 100 nm, wherein the solids content of the dispersion is between 70 and 80 wt.-%, and of which between 2 wt.-% and 15 wt.

Abstract: A low cost method for producing a mechanically and thermally stable composite body containing a first layer of a material with a high silicic acid content and an additional component connected to a second layer of a material with a high silicic acid content and an additional component in a second concentration differina from the first concentration is provided. The method involves (a) preparing a first slurry layer having a free surface using a first shirt mass containing SiO2 particles and an additional component dispersed in a first dispersing agent, (b) providing a second slurry mass containing SiO2 particles and an additional component in a second concentration dispersed in a second dispersing agent, (c) forming a composite-body intermediate product by applying the second slurry mass to the free surface of the first slurry layer, and (d) heating the composite-body intermediate product while forming the composite body.

Abstract: The invention relates to a process for producing a paste-like SiO2 composition using an SiO2 slip which allows simple intermediate storage and transport conditions without the processability of the slip to give the paste-like SiO2 composition being impaired thereby. According to the invention, it is for this purpose proposed that a homogeneous SiO2 base slip be subjected to a drying step to form a dry SiO2 composition and subsequently be processed further by means of a remoistening step to give the paste-like SiO2 composition, where the remoistening step comprises the addition of liquid to the dry SiO2 composition to form a paste-like kneadable SiO2 composition having a solids content of more than 85% by weight. The invention further relates to the use of a paste-like SiO2 composition as repair composition.