Synchrotron X-Ray Study of the Crystal Structure and Hydrothermal Degradation of Yttria-Stabilized Tetragonal Zirconia Polycrystal

Structural study with synchrotron X‐ray diffractometry was made on phase separation phenomena in 2, 3, and 4 mol% Y2O3‐stabilized tetragonal ZrO2 polycrystal (abbreviated as 2, 3, and 4Y‐TZP, respectively). The sintered body of 3Y and 4Y‐TZP underwent phase separation into high and low yttrium regions as sintering temperature increased, and the tetragonal phase was assigned to both regions. The sintering body is less separated, and a large monoclinic phase was detected in 2Y‐TZP. Analysis of aging kinetics of tetragonal‐ to monoclinic‐phase transition showed that the fraction of the transformable phase agreed with that of the low yttrium region.