Formation of Calcareous Deposits Under Different Modes of Cathodic Polarization^☆ Available to Purchase

Calcareous deposits that formed in natural seawater upon ASTM⁽¹⁾ A710 (UNS⁽²⁾ K20747) steel polarized either potentiostatically, galvanostatically, or by a mixed-mode technique (initially galvanostatic followed by potentiostatic) have been studied. Parameters investigated included variation of current density (potentiostatic control) or potential (galvanostatic control) with time, total charge transfer, deposit thickness, thickness-to-charge ratio, deposit morphology, and deposit composition. Based upon these parameters, the mixed-mode technique was judged to provide the deposit with greatest protective properties within the time frame of the experiments. This may be related to the nature of the initial, magnesium-rich film established during he preliminary experimental period; the mechanism of calcareous deposit formation is discussed within this context.