Abstract
The scribing technique has been used to delineate the repassivating kinetics of electrodes. In applying the scribing technique to elucidate the corrosive wear mechanisms on metals, the effect of surface scars on the transient electrochemical response must be carefully considered. The effect of the scratch shape on the ohmic potential created during scribing is an initial step in understanding the results acquired in scratch experiments. By assuming the current distribution to be constant on the scar surface, the mathematical model used by Pearson, Burstein, and Newman has been extended to calculate the ohmic potential resulting from diamond‐shaped scars. In addition, the effect of rectangular and diamond‐shaped scars on the ohmic potential are compared when the scars have equal areas. For large length‐to‐width ratios, the comparison infers that the width of the scratch can significantly affect the potential drop. When the widths are matched, the potential drop resulting from the rectangular scratch is of the same order as, and slightly larger than, that from the diamond‐shaped scratch. Otherwise, the scratch with the larger width will generally produce a larger ohmic potential. For small to moderate length‐to‐width ratios, the potential drop resulting from the diamond‐shaped scratch is larger than that from the rectangular scratch.