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A spontaneous immersion process has been developed to deposit adherent cerium oxide/hydroxide coatings on copper foil from an aqueous bath consisting of cerium nitrate, hydrogen peroxide, and sodium chloride. The spontaneous cerium oxide/hydroxide deposition exhibited characteristics consistent with an immersion process, with the deposition rate decreasing as the copper substrate was coated. A deposition mechanism is proposed in which the reaction of copper with hydrogen peroxide produced near-surface-pH conditions conducive to cerium oxide/hydroxide precipitation on the copper surface. Hydrogen peroxide concentration was varied between 0 and 1 vol % percent ͑as a 30% solution͒, with 0.2% producing the maximum deposition rate of 8-10 nm/min. Hydrogen peroxide concentrations above the optimum concentration resulted in substrate passivation due to the stabilization of copper oxide, which retarded coating formation. Parts-per-million concentrations of chloride ion were found to increase deposition kinetics without affecting the copper dissolution rate, possibly by destabilizing copper oxide formation. Autocatalytic hydrogen peroxide decomposition on the coating surface did not appear to play an important role in the deposition mechanism.

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