Electrochemical testing of sub-micron sized stainless steel particles
2011 (English)In: Eur. Corros. Congr., EUROCORR, 2011Conference paper (Refereed)
Electrochemical testing of corrosion properties such as passivity is well established for massive stainless steels but difficult to conduct for sub-micron particles. These particles need to be attached at an inert electrode surface without changing their corrosion properties. In order to electrochemically investigate passivity properties for AISI 316L stainless steel particles sized less than 45 and 4 μm, respectively, several experimental set-ups have been explored. A paraffin impregnated graphite electrode was found to be the most suitable, reliable and reproducible set-up. Differently produced particles (gas- and water-atomized) of varying size were investigated. In addition, the effect of artificial passivation was explored. Chloride-containing media and media of relevance for human exposure, such as artificial body fluids, were used as electrolytes. For comparison, measurements were also carried out with massive 316L stainless steel. The passive properties of stainless steel particles were shown to be significantly different compared to massive 316L. All particles revealed a significantly higher open circuit potential compared with massive 316L and no passivity breakdown up to 1.2 V vs. Ag/AgCl reference electrode in neutral chloride-rich solutions was observed. No or few transient current peaks related to corrosion processes were observed in neutral solutions, but such events were numerous in aggressive acidic solutions such as 0.7% HCl. Particle dissolution effects were dependent on the particle manufacturing process, on artificial passivation, and on particle size. The relatively high open circuit potential determined for these particles (up to 0.6 V vs. Ag/AgCl in neutral saline solution) is assumed to be the consequence of manganese oxides identified on the surface of the 316L particles, which are not present on the surface of massive 316L. The electrochemical results are compared with data from parallel studies assessing metal release and surface compositional properties of the 316L particles.
Place, publisher, year, edition, pages
, European Corrosion Congress 2011, EUROCORR 2011, 3
IdentifiersURN: urn:nbn:se:kth:diva-150612ScopusID: 2-s2.0-84860879466ISBN: 9781618394125OAI: oai:DiVA.org:kth-150612DiVA: diva2:744439
European Corrosion Congress 2011, EUROCORR 2011, 4 September 2011 through 8 September 2011, Stockholm
QC 201409082014-09-082014-09-082014-09-08Bibliographically approved