Chemical State Analysis of Copper Corrosion Products Including Patina by Voltammetry

Abstract

The previously developed voltammetric method using a strongly alkaline electrolyte (6 M KOH + 1 M LiOH) as the supporting electrolyte was applied for simultaneous determination of copper corrosion products, including the oxides and patinas. The reduction peaks of these chemical species could be separated in the electrolyte. When the method was applied to samples with patina, the fast exchange reaction presumably occurred between SO₄^2－ or CO₃^2－ ions in patinas and OH^－ ions in the electrolyte, so that the reduction peak of patina could be observed at potentials close to that of Cu(OH)₂.