EFFECT OF TA2O5, NB2O5, AND HFO2 ALLOYING ON THE TRANSFORMABILITY OF Y2O3-STABILIZED TETRAGONAL ZRO2

The addition of Ta2O5, Nb2O5, and HfO2 enhanced the transformability of Y2O3‐stabilized tetragonal ZrO2 polycrystal (Y‐TZP), which was indicated by an increase in phase transformation temperatures and fracture toughness of Y‐TZP. Comparison of the alloying effects of these oxides on the transformability and crystal structure of Y‐TZP suggested that an alloying oxide which increases the c/a axial ratio (tetragonality) of TZP also increases the transformability. Empirical equations to predict the tetragonality are proposed. Calculated tetragonalities showed good agreement with measured values in the systems ZrO2‐Y2O3‐Ta2O5, ‐Nb2O5, and ‐HfO2. Copyright © 1990, Wiley Blackwell. All rights reserved