Abstract: In a known method for producing a quartz glass component, a crystal formation layer containing a crystallization promoter is produced on a coating surface of a base body of quartz glass. Starting therefrom, to provide a method for producing a quartz glass component of improved thermal strength and long-term stability which displays a comparatively small deformation particularly also in the case of rapid heating-up processes, it is suggested according to one aspect that a porous crystal formation layer containing amorphous SiO2 particles is produced with a mean thickness in the range of 0.1 to 5 mm, and that a substance which contains cesium and/or rubidium is used as the crystallization promoter.

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: 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: Systems and methods may be used to determine, allocate, and receive a progress-based load delivery settlement. A method may include activating a progress-based load delivery settlement session for a carrier account corresponding to a carrier. The method may include transmitting or receiving, in response information, such as from a GPS unit indicating that a load has been picked up by the carrier, a first percentage of a settlement to the carrier account. The method may include transmitting or receiving, in response information, such as from a GPS unit indicating that the carrier has passed a milestone, a second percentage of the settlement in the carrier account.

Abstract: In a known method for producing a quartz glass component, a crystal formation layer containing a crystallization promoter is produced on a coating surface of a base body of quartz glass. Starting therefrom, to provide a method for producing a quartz glass component of improved thermal strength and long-term stability which displays a comparatively small deformation particularly also in the case of rapid heating-up processes, it is suggested according to one aspect that a porous crystal formation layer containing amorphous SiO2 particles is produced with a mean thickness in the range of 0.1 to 5 mm, and that a substance which contains cesium and/or rubidium is used as the crystallization promoter.

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: Common solar radiation receivers are equipped with a chamber for transmission of an operating gas which is directed along to an absorber for solar radiation for thermal absorption. The absorber has a dome-shaped entry window made of quartz glass, wherein the inner side facing the absorber assumes a nominal interior temperature Ti of at least 950° C. during proper use, preferably at least 1000° C., whereas the outer side facing away from the absorber is exposed to the environment and subject to risk of devitrification. The invention relates to modifying the known solar radiation receiver so that a high absorber temperature can be set and thus a high efficiency of the solar thermal heating is enabled, without increasing the risk of devitrification in the region of the outer side of the entry window.

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 component includes joining individual wall parts, especially for producing a melting crucible for use at a high operating temperature in a crucible-pulling method for quartz glass, wherein at least two wall parts of a refractory metal or of a base alloy of a refractory metal are provided, butt-joined to form a joint and joined together by sintering at a temperature above 1500° C. to form the component. A sealant is inserted into the joint to provide a component of improved tightness and to ensure improved sintering of the individual parts of the component. A component produced according to the method, particularly a melting crucible, particularly in a crucible pulling method for quartz glass, has the joint between the butt-joined walls closed in a gas-tight manner by a sealant.

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.

Abstract: A method for producing a large quartz-glass pipe is provided. In a first forming step, an intermediate cylinder made of quartz glass and having an intermediate-cylinder wall thickness and outside diameter is formed by using a forming tool and is then cooled. In a second shaping step, at least one length segment of the cooled intermediate cylinder is fed to a heating zone, heated to a softening temperature zone by zone therein, and, while rotating about the longitudinal axis of the intermediate cylinder, shaped into the large quartz-glass pipe having a final wall thickness and outside diameter. The quartz glass is synthetically produced and has an average hydroxyl group content of 10 ppm by weight or less. If the intermediate cylinder is divided into length segments of 1 cm, adjacent length segments have a difference of less than 2 ppm by weight in the average hydroxyl group content thereof.

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: The present invention refers to a method for producing a component by joining individual wall parts—especially for producing a melting crucible for use at a high operating temperature in a crucible pulling method for quartz glass, in that at least two wall parts of a refractory metal or of a base alloy of a refractory metal are provided, butt-joined to form a joint and joined together by sintering at a temperature above 1500° C. to form the component. To provide a component of improved tightness and to ensure improved sintering of the individual parts of the component, a sealant is inserted into the joint. Furthermore, the present invention refers to a component produced according to the method, particularly a melting crucible, particularly in a crucible pulling method for quartz glass, in which the joint between the butt-joined walls is closed in a gas-tight manner by a sealant.

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.