Optical interferometry techniques in electrochemistry and corrosion

摘要

Abstract: In the present investigation, an optical corrosion-meter has been developed for materials testing and evaluation of different corrosion phenomena. The idea of the optical corrosion-meter was established based on principles of 3D- holographic interferometry for measuring microsurface dissolution, i.e. mass loss, and on those of electrochemistry for measuring the bulk electronic current, i.e. corrosion current of metallic samples in aqueous solutions. In the present work, images of 3D-interferometric microscopy of stainless steel samples were obtained by the optical corrosion-meter during different stages of electrochemical behaviors of stainless steel in different aqueous solutions. In fact, an early stage of the anodic dissolution behavior of the stainless steel samples was monitor during the anodic polarization measurement in 5N sulfuric acid. In addition, an early stage of pitting corrosion of stainless steel samples was monitored in situ by the optical corrosion-meter during the cyclic polarization test in seawater. The observations of pitting were basically interferometric perturbations detected only on the surface of the stainless steel in seawater. The interferometric perturbations interpreted as a localized corrosion in a form of an early pittings, of a depth ranged between 0.3 micrometer to several micrometers. !10