1999 Volume 107 Issue 1248 Pages 769-771
Effect on α-alumina formation from gibbsite powder by heating was investigated for dry-grinding of gibbsite powder and the gibbsite powder added α-alumina fine powder as a seed. Two powder samples were prepared so as to adjust α-alumina formation temperature to nearly the same temperature at 1100°C. The transformation of intermediate alumina to α-alumina in the ground sample proceeded more homogeneous than that in the seeded sample. The particle size distribution of α-alumina powder calcined from the ground sample become narrower than that from the seeded sample, leading to the formation of sintered body with homogeneous grain size. This may be due to both the formation of much more fine α-alumina particles as nuclei of transformation and to a good dispersion in the intermediate alumina powder by the grinding in comparison with seeding.
