Metastability of the Martensitic Transformation in a 12 mol% Ceria‐Zirconia Alloy: II, Grinding Studies

Observations of the grinding‐induced transformation in singlephase Ce‐TZP materials, referred to in an earlier paper, are presented. Two techniques were used to grind the surface: by hand in a slurry of abrasive particles and with a high‐speed diamond‐impregnated wheel. Significant differences in X‐ray diffraction profiles between the two grinding methods was observed. Limited monoclinic ZrO 2 was detected on the machineground surface, along with the reversal of the tetragonal ZrO 2 (200) peak intensities. On the hand‐ground surface, considerable monoclinic phase was observed. The disappearance of the monoclinic phase with heating was followed by X‐ray diffraction, and the A f was found to exceed 700°C, while the reversal in tetragonal (200) peak symmetry and intensity remained unaltered up to at least 1000°C. Transmission electron microscope studies at various depths below the ground surface were undertaken to identify the differences between these surfaces and fractured surfaces. A simple explanation is proposed for the reversal of the tetragonal peak intensities. This reversal has previously led to the notion of a ferroelastic toughening mechanism in similar TZP materials.