In vitro fatigue behavior of surface oxidized Ti35Zr10Nb biomedical alloy

New compositions of titanium alloys with low Young's modulus as well as multiple surface biofunctionalities are under intense research focus for biomedical applications due to the proven ability of titanium for enhancing implant integration. This study presents the effect of plasma electrolytic oxidation coating on the fatigue response of a novel β-Ti35Zr10Nb alloy tested under physiological conditions (Hanks' solution at 37 °C). The electrolytic oxidation was conducted in calcium acetate/calcium glycerophosphate electrolyte that allowed incorporation of Ca and P within the oxide layer with potential benefits for bone apposition. The fatigue results revealed that the presence of oxide layers decreased significantly the fatigue strength of Ti35Zr10Nb alloy relative to uncoated condition. The specific coating morphology featuring interconnected micropores, microcracks, a scalloped coating/substrate interface, as well as the ceramic nature of the oxide layer was identified as the main factors responsible for the lower fatigue performance of the coated titanium alloy.

► Synthesis of biofunctional plasma electrolytic oxidation coating on a novel β-Ti35Zr10Nb alloy.
► Morphology, elemental composition and structure of porous oxide coating.
► Biomimetic coating by incorporation of Ca and P into the oxide structure.
► Fatigue strength is affected by the specific coating morphology and lack of coating ductility.