Transactions of the INDIAN CERAMIC SOCIETY Vol. 58 1999
Alumina Ceramics Fabricated by Colloidal Processing
S. ANANTHAKUMAR, S. G. K. PILLAI AND K. G. K. WARRIER
Pages : 9-14
DOI:10.1080/0371750X.1999.10799848
Abstract
Alumina ceramics were fabricated using an inorganic
particulate sol as a dispersing medium. High purity alumina
was dispersed in boehmite sol and the interparticle potential
in powder-sol medium was controlled by pH adjustment to
obtain a well dispersed alumina suspension. The dispersion
stability and suspension viscosity with varying pH in
boehmite as well as water medium were. studied and
presented. Alumina-boehmite slurry of more than 80 wt%
solid content was achieved by controlled flocculation and
green compacts were made through slurry compaction.
Packing characteristics of alumina particles under slurry
compaction and dry pressing were also studied and
compared. Alumina slurry containing 14 wt% of boehmite
has the maximum theoretical green density of about 63% at
14 MPa and the theoretical sintered density of about 96.9%
at 1450°C. The microstructural features of sintered alumina
show uniformly distributed grains of 2 Jlm size. Alumina
after sintering has a reasonable hardness of 2500 kg.mm-z.
Slurry compaction is found to be a novel method for
producing high dense alumina ceramics.
