Electrochemical behaviour of ion implanted Ti-6AI-4V in Ringer's solution

Abstract

The effect of ion implantation of various elements (C, N, O, Y, Hf, Pd, Ir, Pt, Au) with different energy–dose combinations on the electrochemical behaviour of the alloy Ti-6AI-4 V in Ringer's solution has been investigated using backscattering spectrometry and potentiodynamic polarisation measurements. After yttrium or iridium implantation, the rest potential was shifted in the positive direction. Non-implanted specimens and those implanted with carbon monoxide, carbon dioxide, hafnium, or noble metals were passive over a wide range of potentials. Implantation of carbon, nitrogen, or yttrium led to breakdown of the oxide film and pitting corrosion. The breakdown potentials decreased with increasing dose. Precipitates of TiC resulted in a more pronounced reduction of the breakdown potential than did TiN precipitates or continuous surface layers.