Laser cleaning of oxide iron layer: Efficiency enhancement due to electrochemical induced absorptivity change

Laser cleaning experiments exhibited a higher cleaning efficiency of the laser cleaning upon application of electrochemical potential on an oxidised iron surface. The objective of this study is to clarify the role of such an electrochemical control on cleaning efficiency. Therefore a study by optical spectrometry at normal incidence in the relevant conditions was performed. From these measurements the optical parameters n and k were deduced. While n is mainly not affected, k changes for a factor of 10 upon application of an electrochemical potential. These results explain the differences in laser cleaning efficiency due to the modified absorption length.