Abstract: The invention relates to a method for cutting refractory metals, in which a solid body (1) made of a refractory metal is mechanically machining cut with a cutting apparatus (4, 7), wherein the cutting apparatus (4, 7) is wetted for cutting with a fluid (6) having at least 50 weight % water, wherein the cutting apparatus (4, 7) is brought to a positive electrical potential in relation to the solid body (1) during cutting. The invention also relates to a disc produced from a refractory metal using such a method, and such a disc that has an oxide layer with a thickness of between 2 nm and 1,000 nm on the cutting surface.

Abstract: The invention relates to a method for cutting refractory metals, in which a solid body (1) made of a refractory metal is mechanically machining cut with a cutting apparatus (4, 7), wherein the cutting apparatus (4, 7) is wetted for cutting with a fluid (6) having at least 50 weight % water, wherein the cutting apparatus (4, 7) is brought to a positive electrical potential in relation to the solid body (1) during cutting. The invention also relates to a disc produced from a refractory metal using such a method, and such a disc that has an oxide layer with a thickness of between 2 nm and 1,000 nm on the cutting surface.

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: 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: SiO2 slurry for the production of quartz glass contains a dispersion liquid and amorphous SiO2 particles with particle sizes to a maximum of 500 ?m. The largest volume fraction is SiO2 particles with particle sizes of 1 ?m-60 ?m, as well as SiO2 nanoparticles with particle sizes less than 100 nm constituting 0.2-15% volume by weight of the entire solids content. To prepare the slurry for use and optimize its flow behavior for later processing by dressing or pouring the slurry mass, and for later drying and sintering without cracks, the slurry has SiO2 particles with a multimodal distribution of particle sizes, with a first maximum in the range 1 ?m-3 ?m and a second maximum in the range 5 ?m-50 ?m, and an 83%-90% solids content by weight of the SiO2 particles and the SiO2 nanoparticles together.

Abstract: SiO2 slurry for the production of quartz glass contains a dispersion liquid and amorphous SiO2 particles with particle sizes to a maximum of 500 ?m. The largest volume fraction is SiO2 particles with particle sizes of 1 ?m-60 ?m, as well as SiO2 nanoparticles with particle sizes less than 100 nm constituting 0.2-15% volume by weight of the entire solids content. To prepare the slurry for use and optimize its flow behavior for later processing by dressing or pouring the slurry mass, and for later drying and sintering without cracks, the slurry has SiO2 particles with a multimodal distribution of particle sizes, with a first maximum in the range 1 ?m-3 ?m and a second maximum in the range 5 ?m-50 ?m, and an 83%-90% solids content by weight of the SiO2 particles and the SiO2 nanoparticles together.

Abstract: A known SiO2 slurry for the production of quartz glass contains a dispersion liquid and amorphous SiO2 particles with particle sizes to a maximum of 500 ?m, wherein the largest volume fraction is composed of SiO2 particles with particle sizes in the range 1 ?m-60 ?m, as well as SiO2 nanoparticles with particle sizes less than 100 nm in the range 0.2-15% volume by weight (of the entire solids content). In order to prepare such a slurry for use, and to optimize the flow behavior of such a slurry with regard to later processing by dressing or pouring the slurry mass, and with regard to later drying and sintering without cracks, the invention suggests a slurry with SiO2 particles with a multimodal distribution of particle sizes, with a first maximum of the sizes distribution in the range 1 ?m-3 ?m and a second maximum in the range 5 ?m-50 ?m, and a solids content (percentage by weight of the SiO2 particles and the SiO2 nanoparticles together) in the range 83%-90%.

Abstract: In a known method for producing quartz glass that is doped with nitrogen, an SiO2 base product is prepared in the form of SiO2 grains or in the form of a porous semi-finished product produced from the SiO2 grains and the SiO2 base product is processed into the quartz glass with the nitrogen chemically bound therein in a hot process in an atmosphere containing a reaction gas containing nitrogen. From this starting point, a method is provided for achieving nitrogen doping in quartz glass with as high a fraction of chemically bound nitrogen as possible. This object is achieved according to the invention in that a nitrogen oxide is used as the nitrogen-containing reaction gas, and that a SiO2 base product is used that in the hot process has a concentration of oxygen deficient defects of at least 2×1015 cm?3, wherein the SiO2 base product comprises SiO2 particles having an average particle size in the range of 200 nm to 300 ?m (D50 value).

Abstract: In a known method for producing a raised marking on a glass object, a suspension containing SiO2 particles is applied to a surface of the glass object as a pattern, and the pattern is compacted to form the marking. Starting from this, in order to enable a cost-effective production of an optically appealing and uniform marking on an object made of quartz glass, which marking is also suited for applications at high temperature or in a contamination-sensitive environment, such as in solar cell and semiconductor production, it is suggested according to the invention that a binder-free suspension be used to create a marking on a quartz glass object, the suspension containing a dispersion liquid and amorphous SiO2 particles having particle sizes of up to a maximum of 500 ?m, of which are between 0.2% by wt. and 15% by wt. SiO2 nanoparticles having particle sizes of less than 100 nm, and the solids content thereof, i.e.

Abstract: A known SiO2 slurry for the production of quartz glass contains a dispersion liquid and amorphous SiO2 particles with particle sizes to a maximum of 500 ?m, wherein the largest volume fraction is composed of SiO2 particles with particle sizes in the range 1 ?m-60 ?m, as well as SiO2 nanoparticles with particle sizes less than 100 nm in the range 0.2-15% volume by weight (of the entire solids content). In order to prepare such a slurry for use, and to optimize the flow behavior of such a slurry with regard to later processing by dressing or pouring the slurry mass, and with regard to later drying and sintering without cracks, the invention suggests a slurry with SiO2 particles with a multimodal distribution of particle sizes, with a first maximum of the sizes distribution in the range 1 ?m-3 ?m and a second maximum in the range 5 ?m-50 ?m, and a solids content (percentage by weight of the SiO2 particles and the SiO2 nanoparticles together) in the range 83%-90%.

Abstract: The present invention relates to a method for bonding components made of high silica material by way of integral joining by forming a high-silica bonding mass between connecting surfaces of the components. A method is provided which permits an inexpensive production of a mechanically and thermally stable composite of components made of a high silica material, particularly for large-area bonded connections for which a contact pressure of more than 5 N/cm2 is applied while the connecting surfaces are being fixed, and/or the path length for possible degassing products from the bonded connection is more than 150 mm. This object is achieved according to the invention in that the SiO2 bonding mass is used in dry form either right from the beginning or at least the SiO2 bonding mass is dried on the connecting surfaces before the joining process and the surfaces to be bonded are subsequently brought into contact and a firm composite is created by way of heating with formation of a SiO2 containing bonding mass.