Micro/nano-structures transition and electrochemical response of Ti-6Al-4V alloy in simulated seawater

Abstract

Fabricating micro/nano-structures on titanium alloy surface can change the anti-corrosion mechanism effectively and influence the corrosion resistance performance of titanium alloy. In this work, micro/nano-structures transition on Ti-6Al-4V (TC4) alloy surface was studied by sandblasting and anodic oxidation. In order to further improve the anti-corrosion performance of anodized TC4 alloy, superhydrophobic surface (SHS) of anodized TC4 alloy was obtained via 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS) modification. The electrochemical tests showed that TC4 anodic films with diverse micro/nano-structures improved the anti-corrosion performance of TC4 alloy. The TC4 anodic film with compact layer exhibited the best corrosion resistance performance which could inhibit the corrosion medium permeating into the metal substrate more effectively than the TC4 anodic films with nanoporous and nanotubular structures. However, the TC4 anodic film with nanotubular structure displayed poor corrosion protection because of its higher specific surface area and larger capillary force. In addition, the TC4 alloy with SHS exhibited excellent anti-corrosion performance due to the synergistic effect of the TC4 anodic film and the SHS.