Determination of instantaneous corrosion rates and runoff rates of copper from naturally patinated copper during continuous rain events
2002 (English)In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 44, no 9, 2131-2151 p.Article in journal (Refereed) Published
Instantaneous corrosion rates of naturally patinated copper of varying age (16 months, 138 and 145 years) have been determined during continuous rain events in the laboratory with electrochemical impedance spectroscopy using a two-electrode cell. The two-electrode cell was found to yield the same information in bulk rainwater as a conventional three-electrode cell. Relatively constant corrosion rates, between 0.2 and 0.6 mum/y, were determined for samples having a two-layer structure with an inner brownish layer of cuprous oxide and an outer greenish layer of basic copper salts (138, 145 years). Samples with cuprous oxide as the dominating phase of the patina (16 months) showed higher and somewhat increasing corrosion rates during a rain event (from 0.6 to 1.2 mum/y). During a continuous rain event, corrosion rates were found to be approximately 10 (brownish patina) and 25 times (greenish patina) lower than corresponding instantaneous runoff rates. The first flush phenomena of the runoff process, with an increased concentration during first flush and a relatively constant concentration during steady state, was indirectly seen as an increase in solution conductivity during the first rain volume followed by relative constant value. The contribution of the concentration in the first flush to the total annual runoff rate was significant for panels having a greenish layer (138, 145 years) whereas it was negligible for panels having a brownish layer (16 months).
Place, publisher, year, edition, pages
2002. Vol. 44, no 9, 2131-2151 p.
atmospheric corrosion, copper, corrosion rate, runoff rate, artificial rain, electrochemical impedance spectroscopy, electrochemical impedance spectroscopy, atmospheric corrosion, electrolyte layers, galvanized steel, ac-impedance, thin, media, roofs, iron, zinc
IdentifiersURN: urn:nbn:se:kth:diva-21705ISI: 000176774400016OAI: oai:DiVA.org:kth-21705DiVA: diva2:340403
QC 201005252010-08-102010-08-10Bibliographically approved