摘要:
In a known method, a SiO2 slip layer is applied to a basic quartz glass body by means of spraying on an SiO2 slip, the slip layer is dried and sintered to form an SiO2-containing functional layer. In order to permit the reproducible production of a functional quartz glass layer, even in the case of surfaces that are curved or inclined with respect to the vertical, having high layer thicknesses which satisfy high requirements on the layer homogeneity, the invention proposes that the slip contain the following components in a dispersion liquid: splintery, amorphous SiO2 granules having a gain size distribution having a D50 value in the range of 3 μm to 30 μm and having a proportion by weight of at least 10% by weight, based on the total solids content; spherical, amorphous SiO2 particles having a particle size distribution having a D50 value in the range of 1 μm to 50 μm and having a proportion by weight of at least 30% by weight, based on the total solids content; SiO2 nano particles having particle sizes of less than 100 nm and having a proportion by weight between 0.2% and 10% by weight, based on the total solids content; and a non-ionic, alkali-free surfactant having a proportion in the range of 0.005 to 0.5%, based on the volume of the dispersion liquid.
摘要:
In a known method, a SiO2 slip layer is applied to a basic quartz glass body by means of spraying on an SiO2 slip, the slip layer is dried and sintered to form an SiO2-containing functional layer. In order to permit the reproducible production of a functional quartz glass layer, even in the case of surfaces that are curved or inclined with respect to the vertical, having high layer thicknesses which satisfy high requirements on the layer homogeneity, the invention proposes that the slip contain the following components in a dispersion liquid: splintery, amorphous SiO2 granules having a gain size distribution having a D50 value in the range of 3 μm to 30 μm and having a proportion by weight of at least 10% by weight, based on the total solids content; spherical, amorphous SiO2 particles having a particle size distribution having a D50 value in the range of 1 μm to 50 μm and having a proportion by weight of at least 30% by weight, based on the total solids content; SiO2 nano particles having particle sizes of less than 100 nm and having a proportion by weight between 0.2% and 10% by weight, based on the total solids content; and a non-ionic, alkali-free surfactant having a proportion in the range of 0.005 to 0.5%, based on the volume of the dispersion liquid.
摘要:
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.
摘要:
Composite material with high resistance to temperature changes and a high density, and having an SiO2-containing matrix with quartz glass grains embedded therein is produced by preparing a suspension from a particle mixture of finely divided SiO2 powder having at least two different particle fractions and of the quartz glass grains, forming a green compact and sintering the compact. The matrix has an SiO2 content of at least 99% by wt. and is formed from at least first and second particle fractions, each of which is present as granules of nanoscale, amorphous, synthetically produced SiO2 primary particles having a mean primary particle size of less than 100 nm. The composite material has an SiO2-containing matrix with an SiO2 content of at least 99% by wt. It is particularly suited for applications such as starting material for producing a permanent mold for melting solar silicon.
摘要:
In a known process for the production of opaque quartz glass a blank is formed from synthetic SiO2 granulate and is heated at a vitrification temperature to form a body of opaque quartz glass. In order to provide on this basis a process for the production of pure opaque quartz glass with a homogenous pore distribution, high density, high viscosity and a low tendency to devitrify, it is proposed according to the invention that the SiO2 granulate to be used is a SiO2 granulate (21; 31) composed of at least partially porous agglomerates of SiO2 primary particles, with a specific BET surface ranging from 1.5 m2/g to 40 m2/g and an apparent density of at least 0.8 g/cm3. A SiO2 granulate (21; 31) suitable for the implementation of the process is distinguished in that it is formed from at least partially porous agglomerates of SiO2 primary particles and in that it has a specific BET surface ranging from 1.5 m2/g to 40 m2/g and an apparent density of at least 0.6 g/cm3.
摘要:
A heat conductive ceramic substrate for semiconductor circuits, comprising polycrystalline aluminum nitride of high density containing as an additive boron nitride or oxides of calcium, magnesium, aluminum, titanium, zirconium, chrome, silicon, and/or rare earth metals. The boron nitride additive concentration ranges between 0.1 and 3% by weight, preferably between 0.5 and 2% by weight. The oxide additive concentration ranges between 0.1 and 5% by weight. The substrate has a significantly higher thermal conductivity than aluminum oxide substrates and is more economincal to manufacture than beryllium oxide substrates.
摘要:
A bipolar electrode has plate-like anode and cathode parts. The anode and cathode parts are secured together, edge-to-edge, to form a single element in one plane by an intermediate connecting piece. The intermediate connecting piece itself is a composite element having parts of materials which are compatible with the respectively adjacent anode and cathode. The two parts of the composite element are joined together by hot isostatic pressure, explosion-plating or diffusion-welding into the composite body, the resultant composite body then permitting welding of the respective anode and cathode plates to the respective anode part and cathode part of the composite element or body.
摘要:
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 μm, wherein the largest volume fraction is composed of SiO2 particles with particle sizes in the range 1 μm-60 μm, 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 μm-3 μm and a second maximum in the range 5 μm-50 μm, and a solids content (percentage by weight of the SiO2 particles and the SiO2 nanoparticles together) in the range 83%-90%.
摘要:
An ideal quartz glass for a wafer jig for use in an environment having an etching effect is distinguished by both high purity and high resistance to dry etching. To indicate a quartz glass that substantially fulfills these requirements, it is suggested according to the invention that the quartz glass is doped with nitrogen at least in a near-surface area, has a mean content of metastable hydroxyl groups of less than 30 wt ppm and that its fictive temperature is below 1250° C. and its viscosity is at least 1013 dPa·s at a temperature of 1200° C. An economic method for producing such a quartz glass comprises the following method steps: melting an SiO2 raw material to obtain a quartz glass blank, the SiO2 raw material or the quartz glass blank being subjected to a dehydration measure, heating the SiO2 raw material or the quartz glass blank to a nitriding temperature in the range between 1050° C. and 1850° C. in an ammonia-containing atmosphere, a temperature treatment by means of which the quartz glass of the quartz glass blank is set to a fictive temperature of 1250° C. or less, and a surface treatment of the quartz glass blank with formation of the quartz glass jig.
摘要:
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.