Filiform corrosion in polymer-coated metals

Filiform corrosion is a type of localized corrosion which affects painted metals (usually steel, aluminium and magnesium). Filiform corrosion often occurs in marine environments and it produces protective coating damage and thread-like metal base attack. This paper reviews some of the research on this type of corrosion. The survey describes the phenomenon and the resulting problems, enumerates the most important factors involved, analyses the proposed mechanisms of initiation and growing of the filaments, summarizes the most usual filiform corrosion standardized tests and the methods of evaluating the extent of the attack, and discusses preventive measures used to try to avoid this problem.