Mitigating Localized Corrosion in Complex Environments through Corrosion Probe Regulated Cathodic Protection
Authors: Tan Yongjun (Mike) Yongjun , Varela Bob 
Published: December 2024

Although progresses in corrosion science and engineering made over the past decades have facilitated the effective control of uniform and general corrosion in many industrial structures, the management and control of localized corrosion in complex engineering environments remains a significant challenge. Localized forms of corrosion remain critical and tenacious threats to the integrity and safety of the huge network of civil and industrial infrastructure assets especially those exposed to complex and varying environmental conditions. An example is localized corrosion of buried steel pipelines that are affected not only by seasonal changes in soil moisture and oxygen levels, inhomogeneous coating defects and coating disbondment, but also by fluctuating stray currents and oscillating mechanical stresses. Another example is localized corrosion on offshore structures such as wind turbines and oil platforms that are affected by multi-zone and dynamically changing marine environmental conditions. Variable and complex environmental conditions can not only lead to changes in corrosion rates, but also in corrosion patterns and mechanisms. Unexpected changes in environment and mechanism could also cause suddenly accelerated localized corrosion damages that are not predictable by conventional laboratory testing and models. This paper reports a new approach to localized corrosion mitigation through the use of localized corrosion probe regulated closed-loop controlled cathodic protection.

A new method based on the use of an electrochemically integrated multielectrode array and closed-loop cathodic protection control technologies have been developed over the recent years. This paper will present typical cases of using the method to mitigate localized corrosion of steel pipeline under disbonded coatings - a serious and difficult issue in the energy pipelines industry. Discussion is extended to future perspectives of using this approach to addressing critical issues in corrosion science and engineering, to preventing the pre-mature failure of engineering materials and to extending the safe operational life of engineering structures that that are vital for the provision of the world’s essential services and the maintenance of its economic activities. It is shown that localized corrosion control will play a critical role in the emerging renewable energy economy because localized corrosion is expected to significantly affect the safety, durability, and sustainability of essential infrastructure required for the production, delivery, storage and utilisation of renewable energy such as wind, solar, hydrogen, geothermal, hydropower, ocean and bioenergy. Future corrosion management of renewable energy infrastructure will need to effectively mitigate localized forms of corrosion by incorporating advanced corrosion monitoring tools, data analytics, artificial intelligence and predictive modelling in order to achieve quantitative, accurate and reliable localized corrosion prediction and closed-loop smart localized corrosion control.

Key references:

Y Tan, Heterogeneous Electrode Processes and Localized Corrosion, Wiley (2012)

Y M Tan, Localized Corrosion in Complex Environments, Wiley (2023)