Raw materials alumina powder null for Verne - i modulo monocrystal

摘要

PURPOSE:To obtain the titled alumina powder, containing a specific amount of a metal (compound) and metallic Ti (compound) as impurities, without bubbles and coloring and capable of providing cylindrical transparent alumina single crystal having suppressed formation of C face. CONSTITUTION:A Ti salt is added to an organoaluminum solution, hydrolyzed and, if necessary, dried and fired to afford alumina powder, having =1mum primary particle size, containing metals of Na, Si, Fe and Me (compound) as metallic atoms in respective amounts of =20ppm and metallic Ti (compound) as Ti in an amount of 10-50ppm and useful as a raw material for producing a single crystal by the Bernoulli process.