Study of cathodic reactions in defects of thermal spray aluminium coatings on steel in artificial seawater

Effect of Corrosion Products and Deposits on the Damage Tolerance of TSA-Coated Steel in Artificial Seawater

“…The simulated potential and corrosion rate were compared with experimental data available in the literature of the electrochemical performance of TSA coating with an intentional damage area of 5% [6,10,14]. All comparison tests evaluated the 300-µm thick coating of pure aluminium (1050 alloy, 99.5 wt% Al) obtained by spraying arc wire deposited on low carbon steel samples at room temperature under conditions of total immersion using seawater artificial according to ASTM D1141-98 [23].…”

“…All comparison tests evaluated the 300-µm thick coating of pure aluminium (1050 alloy, 99.5 wt% Al) obtained by spraying arc wire deposited on low carbon steel samples at room temperature under conditions of total immersion using seawater artificial according to ASTM D1141-98 [23]. Details of the coating obtaining process and experimental methods can be found elsewhere [6,10,14]. Figure 1a shows schematically the shape of the physical specimen.…”

“…The formation and stability of these protective layers are influenced by different variables such as temperature, seawater components, sea current, growth marine, time of exposure, changes in local pH, concentration of OH − and Cl − , just to name a few, making the study of this process a complex subject [13]. In addition, experiments conducted in the lab recognise the difficulty of distinguishing the kinetics of TSA and exposed steel using electrochemical techniques [14].…”

“…However, the quantification of the damage level that TSA can tolerate is not fully explored. While long term tests conclude that TSA provides protection when the defect surface is between 1% and 5% [6,10,14], there are limited data on damage tolerance in the presence of a large cathode.…”

“…However, simulations of TSA-steel coated with defects in seawater have not been configured simultaneously in a single model, and the complexity and influence of different variables are likely to pose challenges in modelling. Therefore, this study proposes the simulation of the damage tolerance of TSA, considering the combined effect of deposits and corrosion products using data from the previous studies of cathodic reactions by Electrochemical Impedance Spectroscopy (EIS) [14].…”