Heraeus Quarzglas Gmbh & Co Kg

Heraeus Deutschland Gmbh & Co Kg

Norbert Traeger

Waltraud Werdecker

Juergen Weber

Christian Schenk

Gerrit Scheich

Bernd Spaniol

Helmut Leber

Jürgen Weber

Joachim Peekhaus

Kerstin Meyer-Merget

Sebastian Pankalla

Werner Feuring

Egbert Stiedl

Friedhold Schölz

Thilo Braemer

Maximilian Kara

Roland Horn

The invention relates to a method for cutting refractory metals, in which a solid body () made of a refractory metal is mechanically machining cut with a cutting apparatus (), wherein the cutting apparatus () is wetted for cutting with a fluid () having at least 50 weight % water, wherein the cutting apparatus () is brought to a positive electrical potential in relation to the solid body () 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.

Method for cutting refractory metals

The invention relates to a process for producing a paste-like SiOcomposition using an SiOslip which allows simple intermediate storage and transport conditions without the processability of the slip to give the paste-like SiOcomposition being impaired thereby. According to the invention, it is for this purpose proposed that a homogeneous SiObase slip be subjected to a drying step to form a dry SiOcomposition and subsequently be processed further by means of a remoistening step to give the paste-like SiOcomposition, where the remoistening step comprises the addition of liquid to the dry SiOcomposition to form a paste-like kneadable SiOcomposition having a solids content of more than 85% by weight. The invention further relates to the use of a paste-like SiOcomposition as repair composition.

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SiOslurry for the production of quartz glass contains a dispersion liquid and amorphous SiOparticles with particle sizes to a maximum of 500 &#x3bc;m. The largest volume fraction is SiOparticles with particle sizes of 1 &#x3bc;m-60 &#x3bc;m, as well as SiOnanoparticles 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 SiOparticles with a multimodal distribution of particle sizes, with a first maximum in the range 1 &#x3bc;m-3 &#x3bc;m and a second maximum in the range 5 &#x3bc;m-50 &#x3bc;m, and an 83%-90% solids content by weight of the SiOparticles and the SiOnanoparticles together.

A known SiOslurry for the production of quartz glass contains a dispersion liquid and amorphous SiOparticles with particle sizes to a maximum of 500 &#x3bc;m, wherein the largest volume fraction is composed of SiOparticles with particle sizes in the range 1 &#x3bc;m-60 &#x3bc;m, as well as SiOnanoparticles 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 SiOparticles with a multimodal distribution of particle sizes, with a first maximum of the sizes distribution in the range 1 &#x3bc;m-3 &#x3bc;m and a second maximum in the range 5 &#x3bc;m-50 &#x3bc;m, and a solids content (percentage by weight of the SiOparticles and the SiOnanoparticles together) in the range 83%-90%.

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Maintal, Germany

Norbert Traeger