Investigations into the relationship between the Corrosion behaviour of CN 108 alloy in sea water and the chemical composition of its corrosion products

摘要

AbstractThis paper deals with the investigation of the corrosion behaviour of CN 108 alloy in sea water by means of surface analysis (SEM, EDS and XPS). The results with samples with different surface finishes (as‐received or pickled), tested in natural or artificial sea water, are discussed. The chemical composition and the morphology of the corrosion products were established and realted to the corrosion behaviour of the alloy. In highly chlorinated sea water the growth of a cathodic film, strongly enriched in manganese, and pitting initiation at the grain boundaries, were observed on both as‐received and pickled samples. The occurrence of general uneven corrosion in unchlorinated sea water is related to the presence of a surface film, strongly enriched in iron, which was neither protective nor homogeneous. The good performance of the alloy in intermediate chlorination conditions is related to the growth of a very compact, protective film, characterized by a balanced enrichment of both Fe and