Fig. 8: Surface waviness analysis of machined rolled samples.

The 3D view of surface waviness in a section of the cavity machined with a–e ECM and f–i LECM along with j methodology for k waviness analysis (error bars of standard deviation of 4 measurements). With both a–e ECM and f–i LECM the crevice sites form at weaker passivated sites and coalesce overtime to generate dissolution regions with passivated ridges as quantified by increasing k Wa and Wdr. h, i Passivation weakening is better with LECM which improves crevice/ridge levelling as indicated by lower k Wa and Wdr.