Abstract
The shrinkage of pure α-A12O3 with very fine particle size was observed continuously in the high temperature dilatometer. The investigation shows that the shrinkage was increased in the following conditions :
1) The particle size was fine:
2) The temperature was high :
3) The atmosphere was neutral.
But the temperature at which the sintering began did not vary with these conditions, and was about 1000-1050°C. The time-rate of height shrinkage was calculated from the isothermal shrinkage curves at 1200°C, 1360°C and 1500°C in air and in argon. It was found that they were proportional to 1/5-power or less than 1/5-power of time, which were smaller than that measured and calculated on coarse powder, because the initial stage of sintering had already passed in this experiment.
