Corrosion Resistances and Passivation of Powder Metallurgical and Conventionally Cast 316L and 2205 Stainless Steels
2013 (English)In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 67, 268-280 p.Article in journal (Refereed) Published
The corrosion resistances and passivation of austenitic 316L and duplex 2205 powder metallurgical (P/M) steels, produced by employing gas atomizing and hot isostatic pressing (HIP), have been compared with those of their conventional cast and forged counterparts. The P/M 316L steel is shown to have a significantly higher pitting corrosion resistance than the conventional 316L steel in 0.5 M HCl. Since the chemical composition and the total amount of inclusions were analogous for the two steels, the effect is ascribed to the finer grained microstructure for the P/M 316L steel yielding a better passive layer. This is supported by photoelectron spectroscopy data demonstrating differences between the thickness and composition of the passive layers for the two 316 L steels. Differences in the passivation process were also found for the different steels as three mixed potentials were observed in the polarization curves for the P/M and conventional 316L steels whereas only one mixed potential at about +0.7 V vs. Ag/AgCl was observed for the two duplex steels in 0.5 M HCl. The results indicate that discussions of the shapes of polarization curves and mixed potentials should be based on the anodic and cathodic partial currents, including the reduction of oxygen. HIP:ed P/M steels are clearly well-suited for applications requiring high pitting corrosion resistances.
Place, publisher, year, edition, pages
2013. Vol. 67, 268-280 p.
steels, passivation, polarization curve, pitting, corrosion resistance, corrosion potential, hydrochloric acid
Research subject Chemistry with specialization in Materials Chemistry
IdentifiersURN: urn:nbn:se:uu:diva-179398DOI: 10.1016/j.corsci.2012.10.021ISI: 000313917700029OAI: oai:DiVA.org:uu-179398DiVA: diva2:544491