Effect of Alumina Addition on the Tetragonal‐to‐Monoclinic Phase Transformation in Zirconia–3 mol% Yttria

The tetragonal‐to‐monoclinic martensitic phase transformation in ZrO–3 mol% Y 2 O 3 (PSZ) containing 0 to 12 wt% Al 2 O 3 was investigated by dilatometry, XRD, and SEM‐EDS methods. The propagation of the transformation into the specimen interiors was suppressed by the addition of Al 2 O 3 . The grain size was independent of the addition of Al 2 O 3 . Both Y 2 O 3 and Al 2 O 3 segregated at grain boundaries. From this segregation behavior, it was suggested that a certain compound or phase of Y 2 O 3 –Al 2 O 3 could be formed at grain boundaries, which would presumably prevent the propagation of the transformation into interiors of PSZ‐containing Al 2 O 3 .