New nanocomposite coating achieves 98% corrosion protection for stainless steel

MUSCAT, Oman — Researchers at Sultan Qaboos University have developed a nanocomposite coating that significantly improves the corrosion resistance of stainless steel under highly acidic conditions, offering a potential solution for industries where metal equipment is routinely exposed to aggressive chemical environments.

Corrosion is a persistent challenge in industrial systems, leading to material degradation, increased maintenance requirements, and shorter service life of equipment. The problem is particularly important in sectors such as chemical processing, oil and gas, and water treatment, where metallic components often operate under corrosive conditions.

In a study published in the Sultan Qaboos University Journal for Science, researchers fabricated a protective coating composed of graphitic carbon nitride (g-C₃N₄) and titanium dioxide (TiO₂) nanoparticles and applied it to stainless steel (SS-316). The coated samples were tested in a 1.0 M hydrochloric acid solution, a highly corrosive environment commonly used to evaluate corrosion protection performance.

Among the formulations investigated, the coating containing 30% TiO₂ delivered the strongest protection. Electrochemical tests showed corrosion inhibition efficiencies of up to 98.2%, while the corrosion rate decreased to approximately 0.003 mils per year. The coating also exhibited the highest charge-transfer resistance, indicating a strong ability to suppress corrosion reactions at the metal surface. Its protective performance remained stable throughout seven days of immersion in the acidic solution.

The researchers found that incorporating TiO₂ nanoparticles into the g-C₃N₄ matrix enhanced the coating’s barrier properties by reducing access of corrosive species to the metal surface and blocking active corrosion sites. Surface characterization and electrochemical analyses confirmed the formation of a stable protective layer that limited corrosion damage under prolonged acidic exposure.

The findings highlight the potential of TiO₂/g-C₃N₄ nanocomposites as advanced protective coatings for stainless steel components used in demanding industrial environments where corrosion resistance is critical for operational reliability and equipment longevity.