Copper dissolution behavior in acidic iodate solutions

Copper dissolution was investigated using electrochemical techniques includ ing potentiodynamic scans and electrochemical quartz crystal analysis. The adsorption of iodate on a copper surface depends on the solution pH and the concentration of iodate. IO3- behaves both as an oxidizer and a passivatin g agent for copper dissolution. At low IO3- concentrations, IO3- acts more like an oxidizer while it passivates the copper surface at higher concentra tions. The copper dissolution rate decreases with increasing solution pH an d increases with increasing concentration of potassium iodate up to 1 wt %. The dissolution rate does not change significantly when the potassium ioda te concentration is >1 wt %. A strong adsorption of IO3- ions on a copper S urface has been observed at higher solution pH's and higher iodate concentr ations. This may be ascribed to the formation of a thin film of Cu(IO3)(2) due to the high surface CU2+ concentration and higher concentration of IO3- adjacent to the copper surface.