Corrosion of Cold Spray Deposited Copper Coating on Steel Substrates

The corrosion behavior of copper cold spray coatings on a carbon steel substrate was compared to that of commercially available wrought copper under the conditions anticipated in a nuclear waste repository. Corrosion potential and linear polarization resistance measurements were conducted over 90 d to 120 d in 3.0 mol/L NaCl under anoxic (1) and oxygenated-to-anoxic (2) conditions to simulate the long (1) and short (2) term redox conditions expected in a Canadian repository. Scanning electron microscopy and x-ray diffractometry were used to observe the morphology of the corroded surface and to identify the corrosion products formed. The two specimens behaved very similarly under both sets of conditions. Negligible corrosion was observed under anoxic conditions and the formation of both Cu+1 (Cu2O) and Cu+2 (Cu-2(OH)(3)Cl) phases occurred under oxygenated conditions. No evidence was observed to suggest the particle boundaries in the cold sprayed coating were preferential corrosion sites.