An optical corrosion-meter has been developed for materials testing and
evaluation of different corrosion phenomena. The idea of the optical corrosionmeter 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. An early stage of pitting corrosion of aluminium and copper in seawater was monitored in situ by the optical corrosion-meter during the cyclic polarization test. The observations of pitting were basically interferometric perturbations detected only on the surface of the aluminium in seawater. The interferometic perturbations interpreted as a localized corrosion in a form of an early stage of pitting, of a depth ranged between 0.3 pm to several micrometers. Consequently, results of the present work indicate that holographic interferometry is very usefull technique as a 3D-interferometric microscope for monitoring pittings at the
initiation stage of the phenomenon for different metallic samples in aqueous solutions.
KEYWORDS: General Corrosion, Pitting Corrosion, Aluminium, Copper,
Holographic Interferometry, cyclic polarization, and seawater.