Phase formation and lattice distortion of Lu 2 O 3 ‐doped ZrO 2 in comparison with Y 2 O 3 ‐doped ZrO 2

Lu 2 O 3 and Y 2 O 3 doping of 8, 11, and 18 mol% in ZrO 2 were prepared by solid solution reaction, aiming to study the phase stabilization of Lu 2 O 3 ‐doped ZrO 2 and Y 2 O 3 ‐doped ZrO 2 in terms of phase formation and lattice distortion. The Rietveld refinement results indicated that Lu 2 O 3 ‐doped ZrO 2 and Y 2 O 3 ‐doped ZrO 2 followed the same trend in terms of cubic phase fraction, increasing from 25%–30% (8 mol%) to 95%–100% (11 and 18 mol%). This phase formation was confirmed by observing the same diffraction ring pattern observed for the Lu 2 O 3 ‐doped ZrO 2 and Y 2 O 3 ‐doped ZrO 2 . The Vickers hardness of the Lu 2 O 3 ‐doped ZrO 2 was 4.3% higher than that of Y 2 O 3 ‐doped ZrO 2 at 8 mol%, but 9.7% and 14.8% lower at 11 and 18 mol%, respectively. This was likely caused by the lattice distortion effect of Y 2 O 3 doping overpowering the field strength difference between Lu 3+ and Y 3+ .