The effect of intermittent cathodic protection on corrosion-resistant alloys exposed to crevice environments in the tide zone

Paper ID: C2025-00527 ABSTRACT: Corrosion-resistance alloys (CRA) are susceptible to crevice corrosion when used as fasteners. In order to prevent corrosion, cathodic protection (CP) is commonly used. Nonetheless, in the tide zone, since the metal is eventually above the water level, this method occurs discontinuously. Additionally, at this moment, the metal surface which is heated by the oil transported internally by the pipe is no longer losing heat to the water, making its temperature increase. In this sense, this work aims to evaluate the effect of intermittent CP on corrosion-resistant alloys exposed to crevice environments in the tide zone. For that, AC‑impedance measurements and microscopy analyses were performed in three different nickel‑based CRA. The results showed that CP has a deleterious effect on crevice corrosion propagation, reducing the impedance moduli by more than an order of magnitude. Additionally, it was observed that depending on the composition of the alloy, this effect may be more pronounced. Finally, the microscopic examination corroborated with the electrochemical results, showing more aggressive attacks for those alloys whose impedance moduli reduced more expressively.