Evaluation of the Effectiveness of Wash Water Additives on the Corrosion Behavior of Metal Structures Exposed to Marine Environments Available to Purchase

Corrosion of military equipment remains a serious problem to all branches of the military, affecting both operational readiness and life cycle costs. Commercial additives have been proposed for inclusion in freshwater rinses used to inhibit corrosion of military vehicles exposed to marine environments. The performance data available for these products are generally qualitative and do not permit reliable assessments of their utility or the actual level of protection that can be anticipated. Manufacturers suggest ways the additives may work, but the active inhibiting agent and its concentration are usually protected as proprietary information. Investigation of the problem is further complicated by the fact that during operations, military vehicles usually experience a wide range of conditions that influence corrosion rates. Based on the premise that corrosion inhibition involves the association of a metal surface with an active inhibiting species, this work investigated the inherent properties of five rinse additives and their influence on the corrosion rates of steel and aluminum through separate experimental procedures. The properties examined were the intrinsic ability of additives to affect seawater corrosion processes, the level of inhibition observed as a function of seawater concentration, and the intrinsic attraction of the additive or a component to a metal surface. Correlations between the resultant test data and ongoing field data were examined in attempts to establish a firm basis for predicting and ranking wash additives relative to practical application.