Effect of neighboring grains on the microscopic corrosion behavior of a grain in polycrystalline copper

By immersing polycrystalline Cu in a solution of 0.1 M NaCl and 0.5 M Na2SO4 the grain dependent electrochemical behavior is studied. In order to exclude possible compositional effects, high purity Cu was used. With the use of Atomic Force Microscopy (AFM) and Electron Backscatter Diffraction (EBSD) it was possible to link the dissolution behavior of a polycrystalline material to specific crystallographic features. The results suggest that the grain orientation has no major influence on the corrosion kinetics. On the other hand, the orientation of the neighboring grains seems to play a decisive role in the dissolution rate.

► High purity Cu was immersed in a 0.1 M NaCl and 0.5 M Na2SO4 solution. ► AFM monitored the difference in attack between different grains. ► EBSD identified the orientation of the differently attacked grains. ► The grain orientation is not the main parameter for the corrosion kinetics. ► The orientation of the adjacent grain determines the dissolution rate.