Rhombohedral Phase in Y ₂ O ₃ ‐Partially‐Stabilized ZrO ₂

Abstract

Tetragonal‐to‐rhombohedral stress‐induced phase transformation was studied by X‐ray diffraction on the ground surfaces of tetragonal zirconia polycrystals and partially stabilized zirconia containing 2.0 to 5.0 mol% Y 2 O 3 prepared by hot isostatic pressing. The rhombohedral phase increased with Y 2 O 3 content and also with hot isostatic pressing temperature. The stability of the rhombohedral phase was studied with regard to surface finish and thermal annealing. The subsequent heat treatment of the specimens was found to cause the reverse rhombohedral‐to‐tetragonal transformation.