L1₂- and L1₀-like cation-ordered structures in ZrO₂–Y₂O₃ ceramics

Y_0.25Zr_0.75O_2−x and Y_0.5Zr_0.5O_2−y phases, with L1₂- and L1₀- like cation-ordered structures, respectively, have been found in ZrO₂–Y₂O₃ ceramics in both the sintered and annealed states. High-resolution electron microscopy, energy-dispersive x-ray spectroscopy and computer simulation have been used to reveal the presence of the phases. The formation of Y_0.25Zr_0.75O2_−x and Y_0.5Zr_0.5O_2−y phases was initiated during the sintering procedure and developed with the increase in annealing temperature and time. Segregation of yttrium, which was prevalent in different regions even within one grain, induced the formation of Y_0.25Zr_0.75O_2−x and Y_0.5Zr_0.5O_2−y phases.