Process for producing aluminium alpha-oxide powder

TLDR: Aluminium oxide powders having a high alpha proportion, crystallite sizes of approximately 0.1 mu m and a narrow particle size distribution are prepared from ordinary Bayer aluminium hydroxide (Gibbsit) or aluminium oxide calcined at a low temperature.

Abstract: Aluminium oxide powders having a high alpha proportion, crystallite sizes of approximately 0.1 mu m and a narrow particle size distribution are prepared from ordinary Bayer aluminium hydroxide (Gibbsit) or aluminium oxide calcined at a low temperature. The starting material is wet-disagglomerated, mixed with alpha aluminium oxide nuclei, dried and calcined. Calcination produces agglomerates which already have the crystallite size required and which only have to be disagglomerated to the particle size required. … The alpha aluminium oxide powders prepared according to the invention are particularly suitable as starting materials for producing high-performance ceramics, for example of blanking dies. … …