The dependence of green and sintered densities of zirconia-toughened alumina (ZTA: Al2O3/15vol% ZrO2) on the properties of spray-dried granules and compaction pressures was studied to differentiate the dominant processing parameter controlling sintered properties. Two sets of spray-dried granules, which differed largely in terms of the morphology and yield stress of granules, were compacted at various uniaxial pressures in the range of 80MPa to 120MPa. The green and sintered densities varied depending on the granule properties and compaction pressure. However, both sets of granules formed by cold isostatic pressing at 500MPa exhibited the same green and sintered densities of about 63% and 99%, respectively, relative to the theoretical density, regardless of the variation of granule properties. This work confirmed that high cold isostatic pressure could overcome the effect of granule properties on the green and sintered densities. The strength of sintered specimens was determined from the size of large hollows in the spray-dried granules remaining after compaction. Details of the compaction behavior in terms of the granule properties were discussed.
