Implementation of a control and monitoring system for a cathodic protection cell to mitigate localized corrosion in fixed and mobile steel structures

Abstract

The current study introduces a novel technique to handle electrochemical localized corrosion in certain limited regions rather than applying comprehensive cathodic protection (CP) treatment. An impressed current cathodic protection cell (ICCPC) was fabricated and firmly installed on the middle of a steel structure surface to deter localized corrosion in fixed or mobile steel structures. The designed ICCPC comprises three essential parts: an anode, a cathode, and an artificial electrolyte. The latter was developed to mimic the function of the natural electrolyte in CP. A proportional-integrated-derivative (PID) controller was designed to stabilize this potential below the ICCPC at a cathodic potential of −850 mV, which is crucial for protection efficacy. The controller of the protection system was designed to automatically activate the ICCPC when the environment of the steel structure is exposed to humidity. At a temperature range from 27 °C to 35 °C, the protection potential, current, and power showed an increase in percentage by 411 %, 688.74 %, and 2842.3 %, respectively when the humidity level rose from 10 % to 100 %. The intended spraying of sodium chloride (NaCl) solution on the structure at different concentrations from 1.5 % to 5 % showed excellent protection against corrosion, notable improvements in electrical conductivity, and reduction in resistance between the anode and cathode. The energy dispersive spectroscopy and scanning electron microscopy (SEM-EDS) analyses confirm effective corrosion inhibition under ICCPC coverage compared to unprotected areas. These tests revealed an absence of oxidation beneath the ICCPC compared with areas outside of its coverage. The areas outside of ICCPC protection showed a reduction in iron and carbon contents from 57.1 % to 47.0 % and 41.4 %–22.4 %, respectively, and an increase in oxygen from 1.6 % to 30.6 %.