Stabilization of a t-ZrO 2 polymorph in a glassy SiO 2 matrix at elevated temperatures accomplished by ceria additions.

Glass-ceramic composites are considered important candidates for load bearing orthopaedic applications owing to their combined salient features of bioactivity and mechanical strength. Herein, we report the impact of ceria (CeO2 ) additions on the structural and mechanical behaviour of ZrO2 -SiO2 binary oxides as a glass-ceramic composite for hard tissue replacements. A wide range of ceria additions to the ZrO2 -SiO2 system have been performed via sol-gel synthesis. The structural behaviour of the synthesized compositions is investigated at elevated temperatures using a combination of XRD, Raman spectroscopy, TEM and SEM. The stabilization of tetragonal zirconia (t-ZrO2 ) and CeO2 in the presence of an amorphous SiO2 matrix under heat treatment up to 1300 °C was confirmed. The t-ZrO2 phase is stabilised through Ce4+ substitution up to 20 wt% CeO2 additions, and above this CeO2 crystallization occurs in the amorphous matrix. The morphological and mechanical behaviour of the ceramic reinforced glass matrix is presented with the CeO2 stabilised system showing mechanical properties comparable with commercial biomaterial systems.