2013:07 Corrosion of copper in distilled water without molecular oxygen and the detection of produced hydrogen

In this report, results are presented for copper which has been exposed to pure anoxic water in the temperature interval of 21 °C to 55 °C up to a total of 19 000 hours. Characterisations of copper surfaces after exposure have been performed ex-situ, meaning after termination of the experiment and exposing the specimen to normal atmospheric environment. Ideally characterisation of surfaces should have been performed with the specimens in the reaction chamber without oxygen supply but this was not possible in the experimental set-up used. Thus it cannot be excluded that formed species on surfaces could have been altered during handling of specimens between exposure and surface analysis.

The results from the surface analysis of exposed copper specimens indicate that the reaction products are predominately comprised of oxide and hydroxide. Furthermore, based on the visual appearance, the reaction products formed are solid and of a three dimensional character. Moreover, depth analysis by ion sputtering shows that hydrogen is present at greater depth from the surface and inwards compared to oxygen. This indicates that corrosion of copper in anoxic water involves a mechanism in which hydrogen atoms present in water molecules form hydrogen gas which partly dissociate and diffuse into the copper metal as hydrogen atoms