• Fiaud, C.
• Tran, Thi Tuyet Mai
• Sutter, E.

Abstract

When water flows over copper, turbulence may be created at different parts of metal surface (such as bends, tees, sudden changes in section), and may be sufficient to cause breakdown of the surface layer, even with a solution that is free from suspended solids. An impinging liquid jet directed at normal incidence onto a copper sample was used in this work. It was generated using a recirculating solution of 10-3 M Na 2 SO 4 , continuously deaerated and heated at 60°C. Two types of copper samples were investigated: a bulk copper electrode was first anodised to form a copper oxide layer, before submitting it to the impinging jet. The polarisation resistance was then measured as a function of the time of impinging. In an other test, an electrolytic copper layer was deposited on an EQCM, then polarisation resistance and mass change were followed as a function of the time of impinging. The results are discussed from electrochemical and mass change measurements, and from scanning electronic microscopic observations. Comparisons are made with the variation of the polarisation resistance measured as a function of time, in the same solution, using a rotating disk electrode, at which no turbulence is assumed to occur

Topics

• impedance spectroscopy
• surface
• copper
• erosion-corrosion