Effects of erosion on corrosion of type 430 and 316 stainless steels in aqueous environments

The effects of erosion on the corrosion of two types of stainless steel in aqueous 0.5M NaCl and 1 M NaCl environments at ambient temperature have been studied using a modified rotating cylinder electrodes system. Erosion by silica particles greatly increased the passive current density for both ferritic type 430 and austenitic type 316 stainless steels. It is suggested that two factors were largely responsible for the observed effects. The impact of the eroding silica particles on the specimen surface destroyed the passive film and removed corrosion products from the specimen surface and impact with the fast moving silica particles generated numerous microplastic deformation sites on the metal surface which were activated owing to the presence of residual stress, dislocations and defects, etc., and the emission of low energy electrons.