Determination of instantaneous corrosion rates and runoff rates of copper from naturally patinated copper during continuous rain events

摘要

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 μm/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).