Optimized corrosion resistance in pure copper via surface mechanical attrition treatment and subsequent annealing

Surface mechanical attrition treatment (SMAT) was used on the surface refinement of pure copper mainly to study the electrochemical corrosion behavior of pure copper in a 3.5 wt% NaCl solution, under grain refinement and short-time annealing conditions. Fine crystalline copper showed higher corrosion resistance than coarse crystalline copper, and the samples with grain refinement exhibited increased corrosion resistance under annealing conditions. This improvement may be attributable to the enhanced passivation of the surface passivation film after grain refinement. In addition, the residual stress after annealing reduces the activation energy of atoms leaving the metal lattice and entering the solution, reducing the dissolution rate of the anode. Consequently, the corrosion resistance of fine crystalline copper is improved. Grain refinement and short-time annealing help design corrosion-resistant pure copper.