Crystallization and Sintering of Amorphous Alumina Powder by CO_2 Laser Irradiation

摘要

A practical method to prepare alpha-alumina bulk with excellent crystallinity,has been developed using fast CO;laser irradiation with a kaleidoscope,rather than extended heat treatment in a high temperature electric furnace.Amorphous alumina powder was synthesized by the chemical solution deposition method,using aluminum trisec-butoxide as a starting material.Laser irradiation of the amorphous powder without organic residues accelerated the crystallization of amorphous alumina to alpha-alumina and allowed the preparation of alpha-alumina in bulk and free from breakage.The alpha-alumina bulk was porous,and its thermal conductivity was at least 10 times less than the value reported for sintered a-alumina.