PULSED LASER DEPASSIVATION OF METALLIC ELECTRODES IN AQUEOUS CORROSIVE MEDIA

Abstract
A large amount of metallic materials in aqueous media (e.g. stainless steels, Nickel alloys ...) are protected from localized aqueous corrosion by thin oxide films grown in situ which passivate the metallic surfaces. The passivity can be disturbed by ionic breakdown or imposed mechanical breakdown of the protective film. In the conventional corrosion studies, a lot of techniques have been developed to simulate a local damage of the passive film which don't allow to reach the electrochemistry of bare metal surface. In this work, a pulsed Nd-YAG Laser and a pulse dye Laser in the range of 1 to 10MW/cm² have been tested to promote a local ablation of the passive film in corrosive media. This paper will be mainly devoted to the analysis of the interaction of the laser beam with a thin passive film in presence of an electrolyte.