The effect of surface treatments on the electrochemical behavior of titanium alloy in seawater by electrochemical impedance spectroscopy (EIS)

Seawater contains many minerals,dissolved gases,including oxygen o2,bacteria and other united or multi-cellular organisms,suspended solids and sediments that sometimes impart high turbidity. chemical and biological characteristics of seawater make it a particularly aggressive environment with respect to many materials in particular titanium. physico-chemical interactions between a metal material and its environment can lead to corrosion of material. deterioration of metal due to microbial activity is called biocorrosion or corrosion induced by microorganisms (cim). because of its economic and environmental importance,cim has been extensively over past five decades and several models studies have been proposed to explain the mechanisms biocorrosion observed. many sectors are affected by cim. mention may be made example: maritime port facilities,plant thermal (heat exchangers). biofilm formation on walls of conduits considerably reduces heat transfer,this is particularly important in case of heat exchanger tubes. we noted that treatment of surface electrode moves corrosion potential to more cathodic values. and more,the short stay of titanium in natural seawater,corrosion potential varies around -250 mv/ag/agcl,and then it reaches less cathodic values to longer residence time. electrochemical impedance measurements showed the presence of one loop relative to the capacitive charge transfer phenomenon of metal/passive layer.