Crevice Corrosion Behavior of CP Ti, Ti-6Al-4V Alloy and Ti-Ni Shape Memory Alloy in Artificial Body Fluids

Crevice corrosion behavior of commercial pure titanium (CPTi), Ti-6Al-4V alloy and Ti-Ni Shape Memory Alloy (SMA) were investigated through an electrochemical methods in Ringer's artificial body fluids. The results indicate that the crevice corrosion occurs for all alloys in Ringer's artificial body fluids at potential of 400 mV. The crevice corrosion for all alloys increases with the increase of corrosion solution temperature. The corrosion potential of Ti-6Al-4V alloy is more positive than that of CP Ti and Ti-Ni SMA, manifesting that the anodic polarization characterization of Ti-6Al-4V is better than those of both CP Ti and Ti-Ni SMA. So its crevice corrosion resistance is enhanced. The dynamic equations of crevice corrosion for CP Ti, Ti-6Al-4V and Ti-Ni SMA are as follows: i(T,CPTi)=0.028 e(-2x10-4t), i(T,T1-6Al-4V) =0.0149 e(-3x10-4t), i(T,T1-NiSMA) =0.4712 e(-7x10-4t), which indicate that the process of the crevice corrosion is controlled by the dissolution of chloride salt film on its surface.