Heraeus Quarzglas Gmbh & Co Kg

Siltronic Ag

Hilmar Laudahn

Martin Trommer

Martin Arndt

Klaus-Uwe Badeke

Gabriele Korus

Walter Lehmann

Thomas Kayser

Udo Gertig

Norbert Otto

Manfred Schwarzbauer

Andreas Brueckel

A method for the production of synthetic quartz glass using a special cleaning device is provided. The method includes (a) evaporating a production material containing a polymerizable polyalkylsiloxane compound while forming a production material vapor, (b) passing the production material vapor resulting from step (a) through a cleaning device to purify the production material vapor, (c) supplying the purified production material vapor resulting from step (b) to a reaction zone in which the purified production material vapor is converted to SiOparticles through oxidation and/or through hydrolysis, (d) depositing the SiOparticles resulting from step (c) on a deposition surface, and optionally drying and vitrifying the deposited SiOparticles resulting from step (d) to form synthetic quartz glass. The cleaning device includes a bulk of porous silica particles which have a BET specific surface area of at least 2 m/g. A device for carrying out the method is also provided.

Process for producing synthetic quartz glass using a cleaning device

The invention relates to a method for producing synthetic quartz glass by vaporizing a polyalkylsiloxane as a liquid SiOfeedstock (), converting the vaporized SiOfeedstock () into SiOparticles, separating the SiOparticles, forming a soot body () and vitrifying the soot body (). According to the invention, the vaporizing of the heated SiOfeedstock () comprises an injection phase in an expansion chamber (), in which the SiOfeedstock () is atomized into fine droplets, wherein the droplets have an average diameter of less than 5 pm, and wherein the atomizing of the droplets takes place in a preheated carrier gas stream which has a temperature of more than 180&#xb0; C.

Method for producing synthetic quartz glass

The invention starts from a method for producing a crucible of quartz glass in that SiOinner layer granules are vitrified in a rotating melting mold, which is covered at least in part by a heat shield, in a light gas-containing atmosphere under the action of a plasma to obtain a transparent inner layer, at least part of the light gas being supplied to the melting mold through a gas inlet of the heat shield. In order to form an inner layer with a particularly low bubble content and with minimal efforts in terms of energy and material, it is proposed that in a layer forming step preceding the vitrifying step a granule layer consisting of the SiOinner layer granules is formed on the inner wall of the crucible, and that the plasma zone and the heat shield are movable together with the gas inlet and are moved laterally in the direction of the granule layer during the vitrifying step taken for vitrifying the granule layer.

Method and apparatus for producing a crucible of quartz glass

A known quartz glass crucible for crystal pulling consists of a crucible wall, having an outer layer which is provided in an external area thereof with a crystallisation promoter which results in crystallisation of quartz glass, forming cristobalite when the quartz glass crucible is heated according to specified use in crystal pulling. The aim of the invention is to provide a quartz glass crucible which has a long service life. As a result, the crystallisation promoter contains, in addition to a silicon, a first component which acts as a reticulating agent in quartz glass and a second component which is free of alkali metals and which acts as an agent forming separating points in quartz glass. The above mentioned components are contained and incorporated into a doping area () of the outer layer () having a layer thickness of more than 0.2 mm.

Quartz glass crucible and method for the production thereof

Known is a method of producing a quartz glass crucible in which a crucible base body is provided at least in part with an inner layer in which the formation of cristobalite is induced by using a crystallization promoter. On the basis thereof, in order to provide an inexpensive method of producing a quartz glass crucible with reproducible characteristics for long service lives, it is suggested according to the invention that the crystallization promoter and a reducing substance are introduced into the inner layer.

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OT Thalheim, Germany

Hilmar Laudahn