Ceramic material, useful to prepare optical element such as lenses and prisms, comprises zirconium, hafnium and fluorine, where ceramic material is stabilized by stabilizer, e.g. oxides of yttrium, scandium, magnesium and calcium

摘要

Transparent ceramic material (I), which is stabilized by a stabilizer comprising at least one yttrium oxide, scandium oxide, magnesium oxide, calcium oxide or lanthanide oxide, comprises zirconium, hafnium and fluorine, where the crystal structure of the zirconium- or hafnium-containing ceramic material is cubical, and the average particle diameter of the crystal is 5-300 mu m. An independent claim is included for a process for the preparation of (I) comprising producing green body using zirconium or hafnium, the stabilizer, and a raw powder containing fluorine with an average primary particle size of 20-500 nm, producing a presinter body by presintering the green body at 500-900[deg] C, producing a sinter body by sintering the presinter body at 1400-1800[deg] C and producing a pressed sinter body by press-sintering the sinter body at 1400-2000[deg] C.