Electrochemical Characterization Of Tin Electrode In Synthetic Seawater

Tin is a common element generally added to many materials to improve the corrosion resistance. This research studies the electrochemical behaviour of tin electrode in synthetic seawater using linear polarization, cyclic voltammetry and EIS and also to investigate the interaction effect of three factors, salinity, temperature and immersion time on the corrosion rate and polarization resistance. Linear polarization is done to study the corrosion rate and polarisation resistance obtained from Tafel plot. Cyclic voltammetry is done to measure the resulting current produced by the Sn electrochemical cell under different parameters of salinity, temperature and immersion time. EIS is used to analyse the chemical processes occurring at the site of the Sn electrode after immersion in synthetic seawater. Design of experiment was used to design the experiment hence the number of samples required prior to experiment can be known. Apart from that it can be used to predict the outcome of the experiment hence it’s easier to come out with a conclusion. For linear polarization, the testing was done based on 3 factors which are salinity, temperature and immersion time. The highest corrosion rate for this testing is 1.6545 mm/year for the sample that has a salinity level of 33ppt, temperature of 25°C and immersion time of 4 days whereas the lowest corrosion rate is 0.00026 mm/year which has a salinity level of 38ppt, temperature of 35°C and immersion time of 2 days. Salinity and temperature factors have an inverse relation to corrosion rate while immersion time is directly proportional to the corrosion rate. For EIS the Nyquist plot play important roles in providing the corrosion rate, as the area plot of semicircle become larger, the corrosion rate will increase. From the testing, equivalent circuit model can be obtained