Dy3+ Occupancy in Zirconia Lattice Affects Tetragonal to Cubic Phase Transitions in Zirconia Toughened Alumina Systems

Current research on zirconia toughened alumina (ZTA) systems employed in total hip joint replacement applications is focused on the usage of alternative stabilizers to improve their properties. Herein, a wide range of dysprosium (Dy3+) additions to ZTA systems have been formed through an in situ method. Dy3+ induced significant structural changes in ZrO2 rather than the α-Al2O3 component of the composite. Dy3+ tends to occupy along the a = b-axis of the ZrO2 lattice to stabilize tetragonal zirconia (t-ZrO2), whereas its enhanced accumulation directed the formation of cubic zirconia (c-ZrO2). As a consequence of phase transition, a different behavior in the emission characteristics was also noticed. However, t- → c-ZrO2 phase transition was not found to affect the paramagnetic behavior of Dy3+ added ZTA systems. The structural stability of the Dy3+ added ZTA systems was preserved until 1500 °C, and moreover it was also determined that optimum Dy3+ content is essential for enhanced mechanical stability of the composite.