A comparative study of the corrosion resistance of a bare Cu-10 Ni alloy and a Cu-10 Ni alloy protected by sodium-diethyl-dithiocarbamate (NaEt(2)dtc) has been undertaken. The experimental conditions varied from quiescent natural seawater to seawater subjected to jet impingement of different fluid velocities. The mechanism of inhibitor action has been suggested that includes the formation of a surface chelate compound between the dissolving metal ion and the (Et(2)dtc)(-) ligand, as well as formation of a 3-D ternary surface complex. The surface layer that incorporates both the inhibitor and the cuprous oxide, represented by the structure: Cu-Ni/Cu2O/Cu(II) organic complex/seawater has shown an excellent protective performance with efficiency > 90% under stagnant and fluid impingement conditions.