Abstract
Titanium alloys with varying boron additions, in Hanks Balanced Salt Solution (HBSS), were characterized using electrochemical impedance spectroscopy (EIS) at varying exposure times. Bode and Nyquist plots were plotted for each substrate. The Bode plots point to the possible formation of a double-layered passive film on the surfaces of all the Ti-6Al-4V alloys containing boron after exposure to the solution for times of 28 to 168 h. At exposure times of 28 to 168 h, the Ti-6Al-4V-1.09B alloy did not show noticeable changes in impedance behavior with respect to increased exposure time. The Nyquist plots demonstrated a shift in the impedance behavior of the substrate from predominantly resistive to a more pronounced capacitive behavior as the exposure time was increased. An equivalent circuit model was fitted to the experimental data and a physical model of the oxide formation has been proposed.
