Stabilization of a t-ZrO2 polymorph in a glassy SiO2 matrix at elevated temperatures accomplished by ceria additions

Abstract

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.