Abstract: A lithium aluminum silicate (LAS) glass-ceramic has an average coefficient of thermal expansion (CTE) in a range from 0 to 50° C. of at most 0±0.1×10?6/K and a thermal hysteresis at least in a temperature range from 15° C. to 35° C. of <0.1 ppm. The LAS glass-ceramic includes (in mol % based on oxide): SiO2 60-<70; Li2O 7-9.6; MgO+ZnO>0.5-1.5; R2O>0.5, where R2O is Na2O and/or K2O and/or Cs2O and/or Rb2O; and nucleating agent with a content of 1.5 to 6 mol %. The nucleating agent is at least one component selected from the group consisting of TiO2, ZrO2, Ta2O5, Nb2O5, SnO2, MoO3, WO3 and HfO2.

Abstract: The present invention relates to a glass ceramic having improved thermal expansion characteristics and to the use thereof in a precision component.

Abstract: The present disclosure relates to a method for at least section-wise separating a glass element into at least two glass sub-elements along a separation face and a glass sub-element which is manufactured and/or can be manufactured in particular by the method according to the disclosure.

Abstract: A method is provided for determining the thermal expansion of a low thermal expansion material with very high accuracy of at most +/?3 ppb/K or less and/or with a reproducibility of at most +/?1 ppb/K or less. A measuring device is also provided that includes an advanced push rod dilatometer.

Abstract: A method for preparing a workpiece for separation is provided that includes providing a workpiece that is transparent for light of a pulsed laser beam, splitting the laser beam into two partial beams using an optical system, directing both partial beams onto the workpiece, and moving the workpiece and the partial beams relative to one another. The partial beams are directed onto the workpiece incident at different angles to the normal of the irradiated surface and superimposed inside the workpiece such that the partial beams interfere with one another to form a sequence of intensity maxima inside the workpiece. The intensity at the intensity maxima is sufficiently high to modify the material of the workpiece so that a chain-like periodic pattern of material modifications is formed along a path defining a separation line.

Abstract: The present invention relates to a precision component and also to a glass-ceramic which can be used for producing the precision component.

Abstract: The present invention relates to a precision component and also to a glass-ceramic which can be used for producing the precision component.

Abstract: The invention generally relates to manufacturing or providing of glass or glass ceramic products. The invention is based on the object to allow for providing glass or glass ceramic products having very accurately characterized thermo-mechanical properties. For this purpose, a deformation of the glass or glass ceramic material is measured at least twice as a function of time with different rates of change in temperature or a mechanical stress. Based on the measurements, relaxation times and weighting factors are determined by modelling. Then, based on the relaxation times and weighting factors related to the distribution of relaxation processes occurring in the product, a time-delayed change of a temperature-dependent or stress-dependent physical quantity, such as thermal expansion or refractive index, is calculated as a function of a predefined temperature change or stress change. The invention is used for selecting during manufacturing suitable glass products exhibiting selected time-delayed properties.

Abstract: A method is provided for determining the thermal expansion of a low thermal expansion material with very high accuracy of at most +/?3 ppb/K or less and/or with a reproducibility of at most +/?1 ppb/K or less. A measuring device is also provided that includes an advanced push rod dilatometer.

Abstract: The invention generally relates to manufacturing or providing of glass or glass ceramic products. The invention is based on the object to allow for providing glass or glass ceramic products having very accurately characterized thermo-mechanical properties. For this purpose, a deformation of the glass or glass ceramic material is measured at least twice as a function of time with different rates of change in temperature or a mechanical stress. Based on the measurements, relaxation times and weighting factors are determined by modelling. Then, based on the relaxation times and weighting factors related to the distribution of relaxation processes occurring in the product, a time-delayed change of a temperature-dependent or stress-dependent physical quantity, such as thermal expansion or refractive index, is calculated as a function of a predefined temperature change or stress change. The invention is used for selecting during manufacturing suitable glass products exhibiting selected time-delayed properties.

Abstract: A roller-equipped annealing lehr for flat glass, having a roller conveyor inside a lehr housing, with heating units arranged in pairs above and below the roller conveyor, in rows situated one after another and extending transversely to the feed direction. Temperature regulators are provided with predetermined desired values and actual temperature values that are measured in a position-dependent fashion. In order to achieve a desired stable temperature distribution and to prevent stresses in the flat glass, a feedback loop arrangement for at least one pair of heating units situated at a particular position in the row, presets as a control variable the heating output required to predetermine the temperature distribution in the region of this position as a predetermined portion of a heating output, which is calculated based on at least one actual temperature value measured at a different position in the row.

Abstract: The method for producing single crystals includes drying crystal raw material by removing water, reaction of impurities with a scavenger, preferably a metal halide, and homogenizing the melt. The method is performed with the raw material in a melt vessel with a variable-sized through-going opening, in which drying occurs at 100° C. to 600° C. for at least 20 hours with a geometric conductance value for the through-going opening of 2.00 to 30.00 mm2; the reacting occurs at 600° C. to 1200° C. for at least nine hours with a geometric conductance value of 0.0020 to 0.300 mm2 and the homogenizing occurs at above 1400° C. for at least six hours with a geometric conductance value of 0.25 to 1.1 mm2. Alternatively the geometric conductance value is the same during drying, reacting and homogenizing and takes a value between 0.25 and 1 mm2.

Abstract: The invention relates to a roller-equipped annealing lehr for flat glass (1), having a roller conveyor, which is accommodated inside a lehr housing, and having heating units (2) that are arranged in pairs above and below the roller conveyor, in rows situated one after another and extending transversely to the feed direction, and are associated with temperature regulators provided with actual temperature values that are measured in a position-dependent fashion and predetermined associated desired values.

Abstract: The method for producing single crystals includes drying crystal raw material by removing water, reaction of impurities with a scavenger, preferably a metal halide, and homogenizing the melt. The method is performed with the raw material in a melt vessel with a variable-sized through-going opening, in which drying occurs at 100° C. to 600° C. for at least 20 hours with a geometric conductance value for the through-going opening of 2.00 to 30.00 mm2; the reacting occurs at 600° C. to 1200° C. for at least nine hours with a geometric conductance value of 0.0020 to 0.300 mm2 and the homogenizing occurs at above 1400° C. for at least six hours with a geometric conductance value of 0.25 to 1.1 mm2. Alternatively the geometric conductance value is the same during drying, reacting and homogenizing and takes a value between 0.25 and 1 mm2.