Impact of surface modification of Ti-6Al-7Nb alloy on electrochemical properties in the environment of artificial blood plasma

In order to improve the hemocompatibility of the Ti-6Al-7Nb alloy the study authors proposed modifying the surface by creating a surface layer using anodic oxidation and the sol-gel method. To verify the usefulness of the two methods and properties of the created layers, electrochemical testing was proposed. Those tests were meant to determine electrical properties that influence corrosion resistance of the alloy before and after the surface modification. Tests were conducted with the use of measuring device equipped with a PGSTAT 302n potentiostat with a FRA2 attachment for impedance tests. Measurements were taken in a human blood environment simulating artificial serum at temperature of 37 °C. To identify phenomenon occurring at the phases border the alloy was additionally tested in artificial serum for 28 days. It was found that a higher voltage value (90 V) in the case of anodic oxidation has a favourable influence on electrochemical properties of the modified surface. In the case of the sol-gel method, a thin layer of SiO₂ (some 150 nm) baked at a temperature T = 430 °C has the most advantageous set of electrochemical properties. Proper selection of parameters of the surface layer deposition process has a direct influence on the success of implant implantation surgery.