Grain growth and phase separation of ZrO₂-Y₂O₃ ceramics annealed at high temperature

The behavior of grain growth and phase separation of sintered ZrO₂-2-8 mol.% Y₂O₃ ceramics annealed at high temperatures were investigated by means of SEM, EPMA, XRD and quantitative metallography. The results show that the grain size increases with increasing Y₂O₃ content and annealing time. The grain growth is very slow in the single tetragonal phase region and very fast in the single cubic phase region. However, in the c+t two-phase region, the cubic graibs grow more slowly, but tetragonal grains more quickly than in the single cubic or tetragonal phase regions. With the increase of annealing time in the c+t two-phase region, the Y₂O₃ content in the tetragonal phase decreases, but remains almost unchanged in cubic phase.