The Influence of ZnO Oxide Layer on the Physicochemical Behavior of Ti6Al4V Titanium Alloy

Titanium and its alloys are characterized by high biocompatibility and good corrosion resistance as a result of the ability to form a TiO2 oxide layer. However, based on literature data it can be concluded that titanium degradation products, in the form of titanium particles, metal-protein groups, oxides and ions, may cause allergic, inflammatory reactions and bone resorption. The corrosion process of Ti6Al4V in the human body environment may be intensified by a decreased pH and concentration of chloride compounds. The purpose of this article was to analyze the corrosion resistance of the Ti6Al4V alloy, obtained by the selective laser melting method in a corrosion solution of neutral pH and in a solution simulating peri-implant inflammatory conditions. Additionally, the influence of zinc oxide deposited by the atomic layer deposition method on the improvement of the physicochemical behavior of the Ti6Al4V alloy was analyzed. In order to characterize the ZnO layer, tests of chemical and phase composition as well as surface morphology investigation were performed. As part of the assessment of the physicochemical properties of the uncoated samples and those with the ZnO layer, tests of wetting angle, pitting corrosion and impedance corrosion were carried out. The number of ions released after the potentiodynamic test were measured using the inductively coupled plasma atomic emission spectrometry (ICP–AES) method. It can be concluded that samples after surface modification (with the ZnO layer) were characterized by favorable physicochemical properties and had higher corrosion resistance.