Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V.

Koninklijke Philips Corporation N.v.

Thomas Hutzler

Andreas Krell

Michel Paul Barbara Van Bruggen

Theo Arnold Kop

Rolf Theo Anton Apetz

Lutz-Michael Berger

Stefanie Hildebrandt

Rolf T A Apetz

Michel P B Van Bruggen

The invention relates to the field of ceramics and concerns a method for use in displays of electronic devices with high mechanical stress, for example. The object of the present invention is to provide a method by means of which thin ceramic parts having thicknesses of substantially <1 mm with high transparency are produced. The object is achieved by a method for producing thin transparent ceramic parts, in which ceramic powders are mixed together with a solvent and a monomer and a photoinitiator, and at least 0.0005% by mass of a photoinitiator is added, the mixture is subsequently introduced into a mould, then the mixture is irradiated for at least 1 min with light which has a wavelength for activating the photoinitiator, the moulded body is subsequently removed from the mould and dried, and then the debinding and sintering of the moulded body is carried out.

Process for producing thin transparent ceramic parts and thin transparent ceramic parts

Transparent spinel ceramics, as they can be used, for example, as protective ceramics, and to a method for the production thereof. Transparent spinel ceramics which preferably contain no visible defects and which have an in-line transmission of more than 82% in wavelength ranges of infrared light, measured between 1000 nm and 2500 nm, at sample thicknesses&#x2267;3 mm. Spinel ceramics transparent in wavelength ranges of infrared light which are composed of sintered magnesium aluminum spinel having an average structural grain size of &#x2266;10 &#x3bc;m and having maximally 0.5 mass % overall of homogeneously distributed additives of calcium and/or strontium and/or barium which are present in a concentration, expressed respectively as an oxide, of 0.005 to &#x3c;0.2 mass % CaO and/or 0.005 to &#x3c;0.5 mass % SrO and/or 0.005 to &#x3c;0.5 mass % BaO.

Transparent spinel ceramics and method for the production thereof

The present invention relates to highly dense translucent and transparent aluminium oxide components for applications, e.g. in the lighting industry, where a fine crystal size has to be obtained and stabilized for use at temperatures of 800&#xb0; C. or more. Disclosed are high-strength polycrystalline alumina products which include 0.001-0.5 weight-% ZrOstabilizing a fine crystal size &#x3c;2 &#x3bc;m or, preferably, &#x3c;1 &#x3bc;m if used at temperatures of 800&#xb0; C. or more. The microstructure exhibits an extremely high relative density enabling a high real in-line transmission &#x3e;30% measured over an angular aperture of at most 0.5&#xb0; at a sample thickness of 0.8 mm and with a monochromatic wavelength of light &#x3bb;, preferably, of 645 nm.

Transparent polycrystalline aluminium oxide

Transparent polycrystalline sintered ceramic of cubic crystal structure. The invention relates to the field of technical ceramic and relates to transparent polycrystalline sintered ceramics of cubic crystal structure for applications with increased mechanical stress, e.g., as protective or armoring ceramic. Provided are sintered ceramics that combine a high transmission of RIT&#x3e;75% of the theoretical maximum value with a distinctly improved hardness. Transparent polycrystalline sintered ceramics of cubic crystal structure with a real in-line transmission RIT&#x3e;75% of the theoretical maximum value measured on 0.8 mm-thick polished plates and for light of a wavelength between 600 and 650 nm, and with an average grain size D in the range of 60 nm&#x3c;D&#x3c;10 &#x3bc;m are provided.

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Dresden, Germany

Thomas Hutzler