Examination and prediction of corrosion fatigue damage and inhibition

Abstract

AbstractThe United States Department of Defense (DoD) estimated that the annual cost of corrosion to weapon systems and infrastructure in 2014 exceeded $18 billion and that the number was likely to continue to rise. Corrosion affects military readiness by taking critical weapon systems out of action, due to the degradation of equipment. Unfortunately, as the warfighters demand more from their systems, corrosion prevention and control is frequently traded during the acquisition cycle for weapon system performance. As a result, the DoD remains entrenched in a find-and-fix corrosion management philosophy which is expensive and unsustainable. Better standardized laboratory procedures are needed to help the DoD develop (1) a fundamental understanding of corrosion damage, (2) material performance data relevant to corrosion damage, (3) prediction methodologies to help mitigate the effects of corrosion nucleated damage and (4) to develop an understanding of how corrosion preventative coatings can slow mechanical damage. This paper addresses the effect of the corrosion inhibitors strontium chromate and calcium molybdate in concentrations relevant to service on corrosion fatigue damage as well as presents development of a test methodology for the examination of the corrosion pit-to-fatigue crack transition to help the DoD improve corrosion protection system selection.