Intergranular Corrosion of Ultrafine Grain Copper Fabricated by ECAP
Corrosion of ultra-fine grain (UFG) copper fabricated by equal-channel angular pressing (ECAP) has been investigated in comparison with that of recrystallized coarse grain (CG) copper. Corrosion current was estimated by a Tafel extrapolation method to examine the kinetics of corrosion in a modified Livingstone etchant, which attack dislocations and grain boundaries preferentially. UFG copper have exhibited a lower corrosion current in comparison with that in its recrystallized coarse grain (CG) counterpart despite the fact that the dislocation density and total fraction of grain boundaries are much greater in UFG copper than in CG copper. Corrosion damage on its surface is macroscopically rather uniform whereas obvious attack at grain boundaries and selective corrosion of some grain interiors were observed in CG copper.
Young Won Chang, Nack J. Kim and Chong Soo Lee
H. Miyamoto et al., "Intergranular Corrosion of Ultrafine Grain Copper Fabricated by ECAP", Materials Science Forum, Vols. 561-565, pp. 2385-2388, 2007