| Characteristics of powders play an important role in the densification
and grain growth during the sintering process of oxide ceramics.
During the process of grinding for reduction of particle size, factors
like impurity, hydration etc have to be controlled by the comminution
period, ratio of material to grinding media (balls) as well as the use
of proper liquid medium.
In this investigation characterization of powders prepared by comminution
of technical grade commercial alumina has been made
with respect to wet grinding media and ratio of weight of balls to
material. Powders thus obtained were examined by chemical analysis
(purity), BET (surface area), SEM (shape and size), particle
size distribution by X-ray (Sedigraph) methods. The influence of
powder properties on the sintering behaviour of compacts was studied
at 1400° and 1500T for two hours.
It was observed that an increased amount of balls reduced the
particle size to a limiting stage with characteristic size distribution;
a corresponding increase in surface area has been noticed. A significant
change followed in the sinterability of these powders, corresponding
to the nature of surface of particles and their size distribution. |
