ABSTRACT
A high-volume fraction of intergranular defects, primarily free volumes and microvoids, is often associated with the ultrafine grain size of the nanomaterials. Corrosion of materials is a continuing problem which results in economic losses of the order of billions of dollars to nations. The corrosion behavior of electrodeposited nanocrystalline nickel of various grain sizes has been investigated. The use of graphene, as a passive layer, delays microbially induced galvanic corrosion of metals for periods more than 100 days. The corrosion rate can be calculated by extrapolating a linear fit to the data of the Tafel plot by excluding the part of the curve at large over potentials. Metallic corrosion is a major problem in oil production, shipping and aviation industries, power plants, pipelines, drinking water systems, bridges, and public buildings. Electrochemical impedance spectroscopy is used to interpret the mechanism of corrosion protection by the metals or alloys.
