Influence of Ultrasound on Corrosion Behavior of SUS304 Stainless Steel with Crevice

Abstract

Anodic polarization on SUS304 stainless steel with crevice was carried out in 3.5 mass% NaCl aqueous solution. After the anodic current density reached i=10, 12 or 50 A/m², the potential at that moment was held constantly for a prescribed period. When an ultrasound (US) was applied to the specimen through the solution during the holding period of the potential, the current density on the specimen surface was measured and compared to that without the application of US. As a result, both the pitting corrosion and the crevice corrosion were largely suppressed by the application of US in the solution, and the corrosion current density changed almost synchronistically with the cyclic application and the stop of US. The above effect of US on the suppression of corrosion of SUS304 steel is attributed to the decrease or suppression of the enrichment of hydrogen ions and chloride ions in the crevice or the pits by the stirring effect of US.