Electrochemical Behavior of Titanium Alloy in 3.5% NaCl Containing Natural Product Substances

摘要

Marine environment is a complex corrosive system and presence of red algae is one of the factors thatinfluence corrosion processes. Biofouling is one of the major impediments in the use of titanium insea-water cooled condensers of power plants, which is otherwise an excellent material with respect tocorrosion resistance. Electrochemical impedance spectroscopy (EIS) experiments were carried out in3.5% NaCl to study the corrosion inhibition effect of red algal extracts on Ti-6Al-4V surfaces. Theresults indicated that the type of extract, the extract concentration and the immersion time affect theinhibition efficiency (IE%). In general, corrosion rate for J1, J2 and J3 [Successive extractions byhexane (J1), ethyl acetate (J2) and methanol (J3)] decreases with increasing its concentration orimmersion time. The order of IE% was found to be J3 J1 J2. Langmuir adsorption isotherm wasfound to fit well the experimental data. Values were calculated for the adsorption process and it is-1 -1 -1 seemed to be in the order of: J3 (365.66 ppm ) J1 (150.42 ppm ) J2 (58.35 ppm ). The resultswere confirmed by Scanning electron microscope (SEM) photos.