Effect of nitrogen ion implantation on the electrochemical behaviour of TA6V in sulphuric medium

We have compared, using cycling voltammetry, the corrosion resistance in (1 M) H2SO4 solutions of TA6V alloy prior to and after N+ ion implantation of unalloyed titanium and of PVD nitrided titanium. The superficial oxides grown during polarization were analysed using GDOS technique: concentration profiles exhibit an enrichment in V and Al on implanted TA6V samples. After a long polarization time at 3 V vs sce the Al enrichment disappears and an important incorporation of sulphur arises. The analysis of the acid solution reveals the preferential dissolution of Al. N+ implantation induces the formation of a TiN layer which acts as a diffusion barrier for Ti4+; the oxide layer is thinner. (author)