Heraeus Quarzglas Gmbh & Co Kg

Heraeus Quarzglas Gmbh

Johann Leist

Waltraud Werdecker

Udo Gertig

Heinz Fabian

Rolf G&ouml;bel

Wolfgang Englisch

Helmut Leber

Bruno Uebbing

Dietmar Hellmann

Martin Arndt

Rainer Koeppler

Helmut Fritz

Erich Rosin

Rolf Göbel

To optimize a known method for producing a composite body from a basic body of opaque quartz glass and a dense sealing layer, in such a way that the basic body can be provided with the dense sealing layer without any significant changes and deformations in the opaque material being noticed, the invention suggests a method comprising the following steps: (a) producing the basic body by using a first slip which contains larger amorphous SiOparticles; (b) providing a second slip which contains smaller amorphous SiOparticles and the composition of which differs from that of the first slip at least in that it contains SiOnanoparticles in the range between 0.2% by wt. to 15% by wt. and which is distinguished by a relatively low vitrification temperature; (d) producing a slip layer from the second slip on a surface of the basic body, drying the slip layer, and (e) subsequently vitrifying the slip layer with formation of the dense sealing layer.

Method for the production of a composite body from a basic body of opaque quartz glass and a tight sealing layer

In a device () for the manufacture of a quartz glass crucible (), one section () of a wall () of the rotating quartz glass crucible () is heated at one time by means of at least two electrode arrangements () distributed uniformly at the circumference of the quartz glass crucible () and generating a first and another electric arc. By providing several electrode arrangements (), the cooling-down phase of the sections () until their reaching the subsequent heating zone () can be shortened, and thus an undesirable high temperature difference of the wall () can be avoided. Moreover, the required thermal output of each individual electrode arrangement () can be reduced, so that evaporation phenomena and connected bubble formation can be reduced. In addition to the higher quality that can be reached in this way, the duration of the manufacturing process is reduced.

Method for producing rotationally symmetrical quartz glass crucibles

A process for manufacture of a component made of opaque synthetic quartz glass, and a quartz glass tube manufactured according to said process. The process comprises (i) providing a starting material in the form of granulated material of highly pure, synthetic SiO comprising at least partially porous agglomerates of SiO primary particles, the granulated material having a compacted bulk density of no less than 0.8 g/cm , (ii) filling the granulated material into a mold and converting it to an opaque quartz glass preform through a process of melting, and (iii) reshaping the preform in a heat reshaping process to obtain a component made of opaque quartz glass. A quartz glass tube is made of quartz glass consisting of a granulated material of synthetic SiO with a lithium content of no more than 100 wt-ppb, and the wall thickness of said component being in the range of 0.5 mm to 15 mm.

Process for manufacture of a component made of opaque synthetic quartz glass

In order to provide a quartz glass crucible distinguished by high purity, high opacity and/or low transmissibility in the IR spectrum, it is proposed on the basis of a known quartz glass crucible of opaque quartz glass with a crucible body symmetrical in relation to a rotational axis, an outer zone ( ) of opaque quartz glass transitioning radially toward the inside into an inner zone ( ) of transparent quartz glass and with a density of at least 2.15 g/cm , that according to the invention, the crucible body ( ) be made of a synthetic SiO granulate with a specific BET surface ranging from 0.5 m /g to 40 m /g, a tamped volume of at least 0.8 g/cm and produced from at least partially porous agglomerates of SiO primary particles. A process for producing a quartz glass crucible of this kind is distinguished according to the invention in that for the production of the crucible a SiO granulate is used which was formed from at least partially porous agglomerates of synthetically manufactured SiO primary particles and that it has a specific BET surface ranging from 0.5 m /g to 40 m /g and a tamped volume of at least 0.8 g/cm , the heating effected in such a way that a vitrification front advances from the inside outward while an inner zone ( ) of transparent quartz glass is being formed.

Quartz glass crucible and process for the production thereof

Composite material with high resistance to temperature changes and a high density, and having an SiO -containing matrix with quartz glass grains embedded therein is produced by preparing a suspension from a particle mixture of finely divided SiO 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 SiO 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 SiO primary particles having a mean primary particle size of less than 100 nm. The composite material has an SiO -containing matrix with an SiO 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.

Method of producing a composite material having a high SiO2 content, composite material obtained according to the method, and permanent mold made thereof

To facilitate the start of a process using a quartz glass crucible with a crucible body and an inner layer of quartz glass a quartz glass crucible is provided with an inner surface roughened at least in the starting zone region by multiple depressions disposed at a maximum distance of 5 mm from one another. Furthermore, a simple and inexpensive process for the manufacture of such a quartz glass crucible is described, by providing a crucible body with a smooth inner surface of quartz glass and subsequently roughening the inner layer in the starting zone region by multiple depressions disposed at a maximum of 5 mm from one another.

Quartz glass crucible and process for the manufacture of the crucible

Based on a known process for the manufacture of opaque quartz glass, by mixing SiO particles and an additive which is volatile at a melting temperature, forming a body and melting said body with an advancing melt front forming in the body, it is proposed according to the invention that in order to reduce the danger of contamination, a body ( ) be formed with an inner bore ( ) and be heated in such a manner that the melt front ( ) advances from the inner bore ( ) to the outside. The article of pure opaque quartz glass according to the invention has high resistance to temperature change, high mechanical strength and good chemical durability. It is distinguished by an opening ( ) enclosed by an inner wall ( ), with an inner SiO surface layer ( ) having a layer thickness ranging from 30 mm to 500 mm and a density of at least 2.15 g/cm .

Process for making opaque quartz glass and opaque component made according to the process

In a known process for the production of opaque quartz glass a blank is formed from synthetic SiO 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 SiO granulate to be used is a SiO granulate ( ) composed of at least partially porous agglomerates of SiO primary particles, with a specific BET surface ranging from 1.5 m /g to 40 m /g and an apparent density of at least 0.8 g/cm . A SiO granulate ( ) suitable for the implementation of the process is distinguished in that it is formed from at least partially porous agglomerates of SiO primary particles and in that it has a specific BET surface ranging from 1.5 m /g to 40 m /g and an apparent density of at least 0.6 g/cm .

Process for making opaque quartz, for carrying out the process suitable SiO2 granulate, and component of opaque quartz glass

A quartz glass component for a reactor chamber, especially of a plasma etching device, comprises a substrate of a first quartz glass quality with an inner surface having an average roughness depth R,of more than 1 &mgr;m, facing the inside of the reactor. To minimize particles in the reactor chamber, and to give the inner surface high adhesiveness for layers deposited on it and a long service life, a roughness zone is formed on the substrate by an open pore bubble layer made of a second quartz glass quality. The quartz glass component may be made by forming a blank from a granulate containing SiO,, and partial or complete vitrification of the blank by heating to a temperature above 1,000&deg; C. During the forming of the inner surface of the blank, an additional constituent is added to the granulate containing siO,in a roughness zone. The additional constituent reacts during the vitrification to release a gas, which forms a bubble layer during vitrification of the roughness zone.

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Altenstadt, Germany

Johann Leist