Erosion-corrosion interactions and their effect on marine and offshore materials

Increasingly the demands of modern fluid handling systems are for low costs with increased reliability and longevity along with no loss of fluid containment. These cannot be achieved without minimising the material damage caused by the combined surface degradation mechanisms of erosion and corrosion when systems are handling solids or are cavitating. This paper reviews the rationale behind the selection of erosion resistance surfaces for fluid handling equipment and highlights the complexities encountered when these surfaces are exposed to environments which contain sand particles or cavitation in a corrosive medium. The erosion and erosion-corrosion performance of a variety of coatings and bulk surfaces are discussed using volume loss rate versus sand impact energy maps. Synergistic terms are identified using standard deviation ratios of electrochemical current noise. Recent researches on the erosion-corrosion of coatings of aluminium, cermets and nickel aluminium bronze are reviewed as candidates for erosion-corrosion resistant surfaces. Electrochemical techniques designed to monitor the erosion-corrosion mechanisms and coating integrity are used to quantify the synergistic terms present when both erosion and corrosion act simultaneously.