Chromium(III) and Chromium(VI) Surface Treated Galvanized Steel for Outdoor Constructions: Environmental Aspects
2010 (English)In: Environmental Science and Technology, ISSN 1086-931X, Vol. 44, no 11, 4322-4327 p.Article in journal (Refereed) Published
The long-term degradation of chromium(III) (Zn-Cr(III)) and chromium(VI)-based (Zn-Cr(VI)) surface treatments on galvanized steel and their capacities to hinder the release of zinc induced by atmospheric corrosion at non-sheltered urban and marine exposure conditions for two years are investigated.
Compared to bare zinc sheet, both surface treatments revealed high corrosion protection abilities and capacities to hinder the release of zinc, still evident after two years of exposure. The zinc barrier properties of the thinner Zn-Cr(VI) (10 nm) treatment were during the first 100 days of urban exposure slightly improved compared with Zn-Cr(III) (35 nm). However, their long-term protection capacities were inversed.
Released concentrations of total chromium correspond to annual release rates less than 0.000032 (Zn-Cr(III)) and 0.00014 g Cr m-2yr-1 (Zn-Cr(VI)) after one year of urban exposure. Ageing by indoor storage of the surface treatments prior to outdoor exposure reduced the released Cr concentrations from the surface treatments. No Cr(VI) was released from the aged surfaces but from the freshly exposed Zn-Cr(VI).
Marine exposure conditions resulted in a faster reduction of chromate to chromium(III)oxide compared with urban conditions, and a significantly lower amount of both chromium(III) and chromium(VI) released from Zn-Cr(VI) at the marine site compared with the urban site.
Place, publisher, year, edition, pages
2010. Vol. 44, no 11, 4322-4327 p.
Barrier properties, Chromium oxides, Cr concentration, Environmental aspects, Galvanized steels, Indoor storage, Marine exposure, Outdoor exposure, Protection capacity, Release rate, Total chromium, Urban conditions, Urban exposure, Urban site, Zinc sheets, Atmospheric corrosion, Chromates, Galvanized metal, Galvanizing, Zinc
Chemical Sciences Other Environmental Engineering
IdentifiersURN: urn:nbn:se:kth:diva-24693DOI: 10.1021/es1003022ISI: 000278003500047ScopusID: 2-s2.0-77952893663OAI: oai:DiVA.org:kth-24693DiVA: diva2:352851
QC 201010062010-09-222010-09-222011-01-17Bibliographically approved