Corrosion protection of steel by calcareous electrodeposition in seawater (Part 3) - Effects of dilution on deposition

Abstract

To examine the applicability of the cathodic protection, which is accompanied with calcareous deposition, to ferrous structures in estuary areas, a study has been made concerning the effects of seawater dilution on the amount, the composition and the structure of the deposit. The dilution resulted in few effects on the amount of the deposit, until the dilution decreased the salinity to 1/10 of the original value. On the other hand, the Mg/Ca ratio of the deposit was greatly influenced by the dilution. As for the structure, the deposit thickness was sharply increased when the dilution decreased the salinity less than 1/10 of the original value. These results were discussed on the basis of the difference in the crystallization rate and the hydrophilic character between CaCO3 and Mg(OH)2.