Corrosion resistance improvement of Ti-6Al-4V alloy by anodisation in the presence of molybdate ions

A.L. MARTÍNEZ; D.O. FLAMINI; S.B. SAIDMAN

Buenos Aires

Congreso; Xi Congreso Latinoamericano de la Corrosión (LATINCORR 2018); 2018

Nace International

The corrosion behaviour of Ti-6Al-4V alloy in artificial saliva with and without added fluoride ions was studied. The effect of different dissolved-oxygen conditions was also evaluated. In an attempt to increase its corrosion resistance, protective films were formed on the alloy surface in alkaline and acidic solutions in the presence of the corrosion inhibitor molybdate under potentiostatic or galvanostatic control. The effect of molybdate anions on the passivation of Ti-6Al-4V was analysed using open circuit potential (OCP) measurements and polarisation techniques. It was found that the anodisation process increases the titanium content in the oxide film in the form of TiO2 enhancing the corrosion resistance. On the other hand, the inhibitor was incorporated in the formed passive film as it was confirmed by the presence of oxidised molybdenum species in the grown oxide. The alloy surface was examined by scanning electron microscopy (SEM) and it showed that flawed regions in the alloy surface were repaired in the presence of the passivator anion.