Microstructural aspects of Ti6Al4V degradation in H2O2-containing phosphate buffered saline

Ti6Al4V surfaces were exposed to simulated inflammation conditions in H2O2-containing phosphate buffered saline with and without FeCl3. Scanning electron microscopy analysis revealed significantly different degradation modes for the alpha and beta phases. While the a grains are covered by a ca. 400 nm thick protective nanostructured oxide layer, the attack of the beta phase generates a porous microstructure with microscaled cracks and a low polarization resistance. The beta phase is postulated to be sensitive to H2O2 reduction products and less able to generate a passive oxide film. The presence of FeCl3 enhances the cathodic activity and the beta phase degradation.