Dynamic Corrosion Trail of Ti-6Al-4V Alloy in Acid Artificial Saliva Containing Fluoride Ion

The dynamic corrosion behaviors of Ti-6Al-4V alloy in acid artificial saliva containing fluoride ion were traced using electrochemical techniques, optical microscope, scanning electron microscopy, energy dispersive spectrometer and roughness tester. The experimental results indicate that a negative shift of corrosion potential as well as a continuous decrease in impedance for the alloy exists with increasing immersion time, and the degradation rate of the alloy presents the trend of first increase then decrease following the dissolution of passivation film and the formation of corrosion products. The accumulated fluoride ion on the alloy surface accelerates the fracture of passivation film, and the occurrence and development of corrosion of alloy are mainly located at the sites where the formation and shedding of white particles are composed of fluoride compounds, resulting in the decrease of corrosion resisting property of the alloy. A possible model is proposed to elaborate the dynamic corrosion behavior of the alloy.