Stimuli-responsive inhibition of Al substrate corrosion

A recent study introduces a bifunctional epoxy coating doped by cerium (III)-8-hydroxyquinoline for early self-reporting and stimuli-responsive corrosion inhibition of Al substrate.

The work may enlighten an approach to developing self-healing and self-diagnosis coating for premature corroded Al alloy beneath coatings via reactive release and fluorescent visualisation. Image source: analogicus - Pixabay (symbol image).

Recently, anti-corrosion coatings with auto-inhibition and self-reporting on their premature flaws are becoming more and more attractive. In a new work, researchers engineered a cerium nitrate/8-hydroxyquinoline (Ce-HQ) hybrid pigment to endow epoxy coatings with corrosion self-inhibiting and fluorescent self-reporting performances via molecule design. The Ce-HQ pigments were synthesised by physical mixture and then dispersed into the commercial epoxy coating. Once the epoxy coating gets degraded, the underneath aluminum alloy matrix may corrode to produce Al3+ ions, which can compete with Ce3+ ions in the Ce-HQ complex, and then chelate with dissociative 8-HQ to form fluorescent Al-HQ complex, due to the higher bonding strength of Al3+ with 8-HQ than Ce3+ ions.

High corrosion resistance

Thus, not only the responsive releasing of Ce3+ ions and 8-HQ can inhibit the underlying Al alloy, but the newly formed Al-HQ complex could indicate the location and severity of coating flaws through fluorescent emission under UV light. Electrochemical impedance evidenced that the composite epoxy coating containing 1 % mass Ce-HQ presents high corrosion resistance even after 504 h of salt spray test, showing 90 % corrosion refraining efficiency.

The study has been published in Progress in Organic Coatings, Volume 182, September 2023.

Reading tip

The EC Tech Report Waterborne Protective Coatings gives you an extensive up-to-date bundle on protective coatings, focusing on water-borne solutions, with articles, videos and other content handpicked by the European Coatings Team. In addition to cutting-edge technical articles, the Tech Report is rounded off with valuable market insights and key fundamentals on water-borne protective coatings.

Hersteller zu diesem Thema

This could also be interesting for you!