Mapeamento de corrosão localizada através de técnicas eletroquímicas e de imagem

Abstract

This work proposes a unique technique to detect localized corrosion in stainless steels, using colourimetry and image processing. The proposed colourimetric method is based on a chemical indicator of Fe2+ ions. Traditional electrochemical techniques are able to detect localized corrosion processes, but do not report their location on a metal surface, nor do they identify multiple corrosion processes. The technique presented will be compared with open circuit potential measurement (OCP), anodic polarization and electrochemical noise tests, using some metal samples of stainless steel AISI 304L, immersed in NaCl solutions in concentrations of 1M and 3M. The chief advantage of colourimetric methods is that they provide a simple means for determining minute quantities of Fe2+ ions, less than parts per million. Furthermore, a corrosion intensity parameter is presented that uses the area of the coloured indicator to evaluate localized corrosion processes.