Process for preparing fine powders of aluminum nitride

Abstract

Disclosed is a process for preparing fine powders of aluminum nitride, by starting from an aqueous solution of an inorganic aluminum salt, characterized in that said process comprises the following steps: (a) the anion of the inorganic salt of aluminum is at least partially removed by heating, with a colloidal solution of an aluminum compound being obtained; (b) carbon powder is dispersed in said colloidal solution, with a suspension of an aluminum compound and carbon being obtained; (c) said suspension is mixed with a carbohydrate, with a suspension being obtained of an aluminum compound and carbon in a solution which contains the carbohydrate; (d) the suspension obtained from the (c) step is sprayed onto, or dropwise added to, an alkaline solution, with spherical bodies being obtained, which contain aluminum hydroxide and carbon; (e) said spherical bodies are carbothermally reduced and nitrided at a temperature comprised within the range of from 1350.degree. to 1650.degree. C. for a time comprised within the range of from 1 to 24 hours, so that powders containing aluminum nitride are obtained; (f) carbon is removed from said powders by a calcination carried out at a temperature comprised within the range of from 600.degree. to 700.degree. C., for a time comprised within the range of from 1 to 7 hours, under an oxygen-containing atmosphere.

Dependencies are inferred from the claim text.