T.E.M. Study of Boehmite Gels and of Their Transformation into alpha-Alumina

摘要

The evolution in the crystallites organization of boehmite gels transforming into alpha alumina was observed after heat treatment up to 1150 C, for up to 24 hr. It is found that the initial colloidal boehmite crystallites do not grow during the transition alumina stages, but reorder to give parallel strings of pores in large domains. It is suggested that these domains pre-existed in the gel, the limit between two domains corresponding to inevitable mismatches in the edge to face perpendicular linkage. It is argued that each domain results in one paracrystal in the transition aluminas.