The Relationship Between Surface Roughness and Corrosion

Abstract

There are different parameters which can affect electrochemical reactions such as type of electrolyte, velocity, temperature, oxidizing agents, impurities, anode material type and surface treatment. It has been shown that pre-treatment of working electrode (anode) through abrasion techniques is one of the most important parameters affecting on Tafel slopes and consequently corrosion rate. Surface roughness of the metal surface is a major influence on general corrosion, nucleation of metastable pitting and pitting potential as well. In this study different surface roughnesses were created on nickel surface by SiC papers and corrosion properties were compared. Electrochemical impedance spectroscopy (EIS) and profilometry tests were carried out on all the samples and the results were compared with another sample prepared through laser ablation method. Corrosion rate values were calculated and were compared with EIS results for all the samples and a trend in the effect of roughness on corrosion protection of nickel was introduced. SEM and 3D roughness images were taken and compared for all of the samples before and after corrosion tests. Different mechanisms were distinguished for samples created through different methods. The lower the roughness values, the more the corrosion resistance. Sample with patterns created through laser ablation method showed the best protection properties compared to other samples.