Direct observation methods were successfully applied to investigate the por
e structure in green and sintered bodies of alumina ceramics made through a
powder granule compaction process. Fracture strength was measured for alum
ina sintered bodies prepared under three different processing conditions, u
sing granules made through the same procedure. The strength variation among
the sintered bodies was quantitatively correlated to the difference in the
size and concentration of large pores determined by the observation method
s. These pores were developed during sintering.