Influence of Temperature and Exposure Time on the Formation of Calcareous Deposits in Sea Water

Experiment have been perform ed where cylinderica l I 018 steel specimens were polarized to -0.9V (SCE) in natural seawater at 24 at 3•c upon quiescent and nominal sea water veloci ty. The nature of the calcareous deposits that formed was characterized hy monitoring the current density (CD) during the experiments and also the morph ology, composition and th ickn ess of the deposits was invest i gated by SEM and X-ray analysis. The dependence of ca thodic CD and film composit ion upon temperature and exposure time has been st abl ished , and th e observed trends have been in terpreted in terms of the temperature dependance of the solubility limit and the relative nucleation and growth rates for ca lcium and magnesium rich phases.