Corrosion of Cold Spray Deposited Copper Coating on Steel Substrates

Abstract

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-toanoxic (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 (Cu 2 O) 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.

Characterization of commercially cold sprayed copper coatings and determination of the effects of impacting copper powder velocities

“…The application of EBSD will help to optimize the choice of coating parameters required to satisfy mechanical design requirements and to identify the microstructural features which could be important in determining corrosion rates. A detailed study of the corrosion performance of these coatings are published elsewhere [23].…”

The kinetics of copper corrosion in nitric acid

“…During the same time, R p increased to an approximate steady‐state value ~10 2 times greater than that achieved under aerated conditions, confirming a major drop in the corrosion rate when the availability of oxygen was limited. In anoxic solutions, when the oxygen concentration would be ~10 −9 M, [ 24 ] E corr was approximately the same as in the aerated solution, before decreasing slowly to a value less than that observed in argon‐sparged conditions. This decrease was accompanied by an increase in R p to a value ~3 times than that observed under argon‐sparged conditions.…”

Particle-particle interface corrosion of cold sprayed copper in dilute nitric acid solution: Geometry-controlled corrosion mechanism

“…This raises concerns about whether the PPIs in CS materials, where the oxide inclusions universally exist, are prone to corrosion especially under aggressive environments. Despite most studies' revealing unremarkable to marginally increased corrosion damage at the PPIs [13][14][15][16], a recent study [17] showed that CS Cu, a candidate for the corrosion-resistant coa�ng of Canadian-designed used nuclear fuel containers (UFCs) [17], exhibited higher degree of reac�vity at the PPIs when exposed to naturally aerated dilute nitric acid (HNO3) solu�on [18]; however, the exact corrosion mechanism was not inves�gated. Previous studies have shown that dissolved oxygen is paramount in the corrosion of the wrought Cu in dilute HNO3 solu�ons [19][20][21].…”