Fraunhofer-gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Paul Blank

Andreas Krell

Dieter Sporn

The invention relates to oxide ceramic fiber composite materials that, e.g., according to the invention, are used in energy conversion installations. The present invention discloses a fundamentally new concept for the previously incompatible requirements of improved brittle fracture behavior to secure thermal shock stability and damage tolerance in the temperature range of &#x3c;1000&#xb0; C. and of mechanical high-temperature stability to guarantee long-term form stability (creep resistance) of components. This is attained through oxide ceramic fiber composite materials containing fibers with a monocrystalline structure in some areas with an average coherence length of &#x2267;150 &#x3bc;m, with a mesoscopically resistant fiber/matrix interface along the fiber axis at high temperature, which interface on loading above room temperature in a way associated with the propagation of macrocracks shows delaminations that in their extension along the fiber axis are limited microscopically locally to values smaller than the average fiber coherence length and thereby limited to a maximum of 200 &#x3bc;m. The present invention is also directed to the use of the fiber composite materials for components and/or installations for long-term use at high temperatures.

Oxide ceramic fiber composite materials and use thereof

An economical process for the manufacture of a polycrystalline, sintered, ceramic abrasive from a powder raw material is described, which process is characterized by the following process steps: preparation of a slip largely free from polymerizing and/or coagulating additives from the powder raw material; pressureless shallow casting of the slip in a vessel; degassing, drying and crushing of the cast sheet to obtain a fabricated material and sintering of the fabricated material to create the abrasive. This process can be used to manufacture an abrasive that permits extremely high grinding performance due to its extraordinary density and structural integrity.

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Dresden, Germany

Paul Blank