Cathodic protection is an effective method of corrosion control that is widely used across many industries, but is particularly important for oil and gas operators, who often must deal with steel and concrete infrastructure in extremely corrosion-prone environments.
It is estimated that the global cost of corrosion is between 3.5 and 5.2 per cent of world GDP, which, if applied to Australia’s estimated 2024 GDP of $1.75 trillion, amounts to a high estimate of $91 billion spent on remediating assets affected by corrosion. Steel corrodes because it is not a naturally occurring material.
Iron ore is smelted and refined to make steel, a process that adds energy to the metal. Under normal conditions, steel, like most metals except gold and platinum, is thermodynamically unstable and will release energy and revert to its natural state of iron oxide, or rusted iron.
Cathodic protection can also be applied to concrete, but requires periodic inspections and appropriate design to avoid insufficient protection, overprotection, and adverse side effects such as hydrogen embrittlement and stress corrosion cracking.
Zinc is the most widely used metal in steel corrosion control and can provide sacrificial protection through its preferential oxidation when in direct contact with the steel substrate. It also corrodes at a generally slower rate. Analysis by research consultancy Market Research Future (MRF) estimated the cathodic protection market was worth nearly US$10 billion in 2024.
It is projected to grow from US$10.23 billion in 2025 to US$123.81 billion in 2034, at a compound annual growth rate of 3.39 per cent. MRF explained that with escalating environmental concerns and stringent government regulations around corrosion control,companies were increasingly investing in cathodic protection as a preventive strategy to extend the lifespan of critical assets.
The consultancy said: “The growing trend of smart technologies and IoT integration in cathodic protection systems presents a prime opportunity for innovation, enabling real-time monitoring and maintenance to optimise performance. “This technological shift enhances efficiency and reduces downtime, addressing the needs of increasingly complex operational environments.”
Researchers from ETH Zurich in Switzerland last year clarified the mechanism involved in cathodic corrosion protection, resolving a controversial decades-long debate that had preoccupied the chemistry and engineering communities.
Cathodic protection as a principle was first described scientifically by chemist Sir Humphry Davy in 1824. His work has been crucial for over 200 years in sustaining modern infrastructure, including buried gas pipelines and reinforced concrete structures.
Humphry, inspired by two Italians who had recently discovered that electric currents flowed through different precious metals when they were joined together, was able to show in the laboratory that small amounts of base metals could protect large copper sheets from corrosion.
Despite its widespread use, the underlying mechanism behind cathodic protection remained unclear and controversial, explained Ueli Angst, Professor of Durability of Materials at ETH Zurich.
Prof Angst said: “This is a serious problem in engineering and is all the more worrying given that cathodic protection can be considered a key technology for tackling the challenge of infrastructure aging and is used in safety-relevant systems such as high-pressure gas pipelines.
The ETH researchers focused on the interface between steel and the electrolyte. They characterised the spatial and temporal changes in detail, and demonstrated for the first time the formation of a thin metal oxide film on the steel surface. They were able to show that this layer of film was a direct result of the increase in pH due to the electrochemical processes.
Corrosion can affect equipment, pipelines, refineries, and petrochemical plants. It is usually caused by water, carbon dioxide, and hydrogen sulphide, and can be aggravated by microbiological activity.
The direct corrosion costs include the repair, storage, and replacement of corroded metallic equipment and modifying alloys into metals, as well as costs associated with nickel plating and galvanisation.
Economic losses associated with the synthesis, characterisation, and application of compounds as corrosion inhibitors are also calculated as a direct cost.
Indirect costs of corrosion include the leakage of liquids and gases from transport pipelines that can adversely affect machinery performance and transport efficiency. The loss of the oil or gas product can be a significant cost.
Further costs are associated with infrastructure failure, including labour, material, and environmental costs of leaks. A current Australian research project aims to address corrosion and materials degradation of critical engineering structures, such as energy pipelines, with a novel cathodic corrosion control technology.
The Proseware project has field-tested and validated the technology, and it is now being prepared for commercialisation and industry application. T
he project is supported by the Economic Accelerator Seed grant, part of the federal government’s $1.6-billion initiative whose objective is to translate world-leading research into real and tangible innovations.
Deakin University Professor of Applied Electrochemistry and Corrosion Technologies, Dr Mike Yongjun Tan, the Lead Entrepreneur on the Proseware project, explained the solution was smart closed-loop cathodic protection technology.
Closed-loop cathodic protection technology is a smart system that protects metal structures from corrosion by automatically adjusting protection levels based on real-time monitoring.
It mitigates complex and localised forms of corrosion, enabling the extension of the safe operational life and enhancing the safety, durability and sustainability of industrial assets. Prof Tan said: “The project involves re-engineering and demonstrating specialised equipment for protecting engineering infrastructure exposed to complex and tough industrial environment conditions.
“Field testing results have shown the technology’s ability to reduce underground pipeline corrosion by 90 per cent, confirming its ability to significantly extend the life of engineering structure assets.”