Electrochemical impedance spectroscopy (EIS) in the l00 kHz-10 mHz frequency range was employed as the main electrochemical technique to study the corrosion protection behaviour of zinc rich epoxy paint in 3% NaCl solution. The EIS results obtained at the open-circuit corrosion potential have been interpreted using a model involving the impedance of particle to particle contact to account for the increasing resistance between zinc particles with immersion period, in addition to the impedance due to the zinc surface oxide layer and the electrical resistivity of the binder. Galvanic current and dc potential measurements allowed us to conclude that the cathodic protection effect of the paint takes some time to be achieved. The loss of cathodic protection is due to a double effect: the decrease of the Zn/Fe area ratio due to Zn corrosion and the loss of electric contact between Zn to Zn particles. Even when the cathodic protection effect by Zn dust become weak, the substrate steel is still protected against corrosion due to the barrier nature of the ZRP film reinforced by Zn

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This paper was devoted to the study of changes of electrochemical processes (dissolution, passivation) induced by the plastic strain of a 316L austenitic stainless steel in a chloride acid solution (H2SO4 2 M + NaCl 0.5 M). For this purpose, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods have been used for various plastic strain values. In order to only assess the effect of internal stresses created by various dislocation configurations on the dissolution and passivation processes without considering the surface roughness impact, electrochemical experiments have been carried out after polishing the specimen surface. The obtained results show that the electrochemical parameters (corrosion current, activation current peak, high frequency capacitance) change with the increase of plastic strain with the same behavior as the work hardening phases of the material in relation to dislocation pattern.

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