INITIAL-STAGE SINTERING OF BETA-ALUMINA

The initial stage sintering of a plate-like beta-alumina powder compact was investigated by isothermal dilatometry between 1200 degrees C and 1400 degrees C, and-microstructure observation by SEM. The initial stage sintering was divided into two stages. The shrinkage was proportional to time in the first stage and to time(1/3) in the second stage. It is considered that rearrangement is predominant in the first stage, and the mass transport from the grain boundaries to the grain surfaces through the necks is predominant in the second stage. This mass transport is caused probably by the strong anisotropy and idiomorphic habit of the plate-like grains.