IIT Guwahati Unveils Nanocomposite Epoxy Coating to Protect Steel in Marine Environments

A new corrosion-resistant epoxy coating has been developed by researchers at the Indian Institute of Technology (IIT) Guwahati to protect steel structures exposed to seawater and high-salinity conditions. The coating has been strengthened with a specialised nanocomposite designed to enhance durability in harsh marine environments.

The findings have been published in the international journal Advanced Engineering Materials . The study has been co-authored by Prof. Chandan Das from the Department of Chemical Engineering and research scholar Dr. Anil Kumar.

Corrosion, a natural process that gradually weakens metal surfaces, has been identified as a major challenge for steel structures located in coastal and offshore regions. Offshore platforms, marine pipelines, coastal bridges and port facilities have routinely been affected by corrosion-related failures. The phenomenon has also been linked to major industrial accidents, including the 1984 Bhopal gas tragedy and the 1992 Guadalajara explosion.

Although protective barrier coatings are widely used, they often develop microscopic defects over time. These defects allow moisture and salts to enter and damage the underlying metal, reducing the lifespan of critical structures. To address this limitation, researchers worldwide have experimented with incorporating nanomaterials into coatings. Nanomaterials, which are thousands of times smaller than a human hair, are known for improving mechanical strength, durability and protective performance.

In the IIT Guwahati study, a unique combination of reduced graphene oxide (RGO), zinc oxide (ZnO) nanorods and polyaniline (PANI) was incorporated into a single epoxy coating system. No previous research work has combined these three materials in one formulation for marine corrosion protection.

A novel nanocomposite structure was created by attaching ZnO nanorods to reduced graphene oxide sheets and subsequently wrapping the structure with polyaniline. The resulting composite was mixed into an epoxy coating and tested using multiple characterisation techniques.

Improved performance was observed compared to standard epoxy coatings. The developed coating was found to form a denser and more uniform protective barrier, displayed stronger adhesion to steel surfaces and significantly slowed the movement of corrosive elements such as chloride ions. These characteristics indicated its suitability for structures that require long-term protection against seawater.

Potential applications have been identified in sectors such as offshore infrastructure, shipbuilding, coastal pipelines, marine engineering and port structures, where steel is continuously exposed to moisture and high salinity.

Commenting on the study, Prof. Chandan Das stated that the incorporation of the RGO-ZnO-PANI nanocomposite into epoxy coatings offered a promising strategy for long-term corrosion resistance in harsh marine environments. He added that future work would involve assessing long-term durability, performance under real-world conditions and overall life-cycle impact.

The institute has clarified that the research is currently at the laboratory stage, and further validation will be required before any commercial or industrial application is considered.