Nanometer-Scale Corrosion of Copper in De-Aerated Deionized Water

Abstract

Copper is commonly regarded to be immune to corrosion in deaerated deionized electrolytes. The present work shows that, in the absence of hydrogen, copper will corrode on the order of 1 nm/day in deionized water with an O 2 concentration on the order of, or less than, 1 ppb. While a corrosion rate of this magnitude can normally be neglected, it may be catastrophic for nanoscale copper structures utilized in emerging applications to enhance energy transport at the solid-electrolyte interface, such as in cooling advance electronics. This conclusion is supported by a set of experimental and analytical studies that encompass impedance spectroscopy, slow-scan linear sweep voltammetry, thermodynamic calculations for the environment under study, and kinetic simulations. The studies provide a comprehensive insight on details of the corrosion mechanism for copper in deaerated water.

Response to “Comment on Nanometer-Scale Corrosion of Copper in De-Aerated Deionized Water” [J. Electrochem. Soc., 161, C107 (2014)]

“…To explore the influence of system parameters, the simulations presented in our paper 1 were extended to include the oxidation of hydrogen and diffusion of dissolved hydrogen away from the electrode surface.…”

Comment on “Nanometer-Scale Corrosion of Copper in De-Aerated Deionized Water” [J. Electrochem. Soc., 161, C107 (2014)]

“…In the thermodynamic analysis by Cleveland et al, 1 the oxygen line in the Pourbaix diagram (their Figure 5) represents the equilibrium:…”

“…The experimental setup used by Cleveland et al 1 consisted of 30 mL solution purged with 99.9999% N 2 directly from the gas flask through a microporous glass filter. The oxygen content of the gas emanating from the cell was determined as 1-2 ppb oxygen in the gas phase, that is, the partial pressure of oxygen in the measuring cell was p O2 ≈ (1 or 2) 10 −9 atm, given that the total ambient pressure during the measurement was ≈1 atm.…”

“…Cleveland et al 1 state that "If oxygen were present in the experimental system, the concentration associated with the upper bound of 2.5 nm/day would have been 6.5 ppb". We do not understand how the value 6. of solution is 7.5 × 10 −9 mol.…”

“…

Cleveland et al 1 reported a study on the corrosion of copper metal in de-aerated water, stating a corrosion rate of 1 nm/day in deionized water if the O 2 concentration is on the order of, or less than, 1 ppb. (The temperature is not reported, in the following we assume it was ≈25

• C.) We claim that the trace amounts of oxygen in the experiment are sufficient to explain the derived corrosion rates.

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