ABSTRACT
In order to avoid or minimize the pitting corrosion on stainless steels it is possible to enhance the protective capacity of the passive layer from these alloys and one of the methods to obtain this result is the chemical passivation treatment. In this context, the effect of the passivation treatment with nitric acid on pitting corrosion resistance and surface finishing of the AISI 430 and AISI 316L stainless steels in chloride containing media was investigated. To that, two surface conditions are studied for each material: abraded surface and chemically passivated surface according to ASTM A967/967M. The surface finishing was characterized by roughness evaluating and visual analysis through optical microscopy. The corrosion behavior was evaluated by cyclic anodic polarization tests in 0.6M NaCl according to ASTM G61 and the morphology of pitting corrosion was characterized by optical microscopy. According to the results, the chemical passivation treatment had no significant effect on the surface finishing of both steels. Regarding to the pitting corrosion resistance, the AISI 430 and AISI 316L stainless steels subjected to the passivation treatment had the pitting and repassivation potentials increased in relation to the value obtained with the ground surface, that is, the pitting corrosion resistance was improved.
Keywords:
Stainless steels; Chemical Passivation; Pitting Corrosion; Corrosion resistance; Cyclic Anodic Polarization
