At present, corrosion protection of USMC steel components is being implemented through
an initial abrasive blasting of the metal substrate followed by the application of solvent or water
based coatings, which does not appear to provide sufficient long-term corrosion protection,
especially if the coating is partially disrupted exposing the base metal. To address this issue,
primer coatings, containing high concentrations of sacrificially available Zn, can be used for
long-term protection of steel. Electrochemical tests were conducted to determine the corrosion
performance of various commercially available Zn-rich coating products applied to steel
immersed in simulated seawater for up to 2,000 hr. Initial findings show distinctive corrosion
protection of the Zn-rich coatings, manifested by the difference in the open circuit potentials
and corrosion rates between the coatings tested. For open circuit potentials more noble than
-750 mV, electrochemical measurements indicated some corrosion in progress of steel and
poor galvanic protection by the coating. At more negative potentials, enhanced galvanic
protection by the surrounding coating was noted for some of the Zn-rich coatings tested,
resulting in larger protective currents and prevention of steel corrosion for up to 2,000 hr of
exposure.