Electrochemistry, a tool for the corrosion engineer

Electrochemistry is not a primary science, since electricity is a corollary of both chemistry and physics, through thermodynamics and kinetics. Its impact in technology, and in chemical engineering too, is limited to special restricted areas, like electrodeposition, energy storage (with the well known and critical limitations), chlor-soda industry and some electrometallurgy ( copper, aluminium etc.), while there is a wide use of electrochemical devices. Provided that corrosion engineering be, outside US, a real profession, corrosion scientists are actually the main copy-writers of electrochemical methods in corrosion research in the laboratory while anticorrosion technologists tend to trust physical and/or mechanical methods both for testing and for monitoring, as well as for forecasting reliability and expectancy of useful service life of structures. Moreover, also in failure analysis often physical, chemical, mechanical test methods are used (SEM; TEM, EDAX etc.) instead of electrochemical ones. International Standards concerning electrochemical testing and monitoring methods are rare, and some of them since long time remained in form of Draft (ISO 16773 1-4 - 2007-2009). The evolution of electrochemical methods in corrosion research is reviewed and some examples of the few instances when electrochemistry is usefully employed in corrosion control on site is described: - corrosion control of steel pipelines through Rp monitoring; - radio-monitored electrochemical noise on US Navy ships; - EIS monitoring on steel bridges; - EIS monitoring of structures underwater; - rebar corrosion monitoring on concrete viaducts.