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Tannin-rich pigments enhance electrochemical performance of anticorrosive paint systems
Researchers synthesise zinc tannate pigments from Tara pods and demonstrate that these bio-based complexes outperform conventional anticorrosive pigments. Alkyd primers, in particular, benefit from their strong inhibitive action.
Hydrolysable tannins are natural polyphenols found in various plants. Tara pods from Peru contain particularly high tannin levels and offer a low-impact, renewable source for industrial applications. Their ability to complex with metal ions makes them attractive candidates for green anticorrosive pigments.
In this study, zinc-rich tannate pigments were synthesised from Tara powder and evaluated for corrosion protection. Direct current electrochemical techniques and electrochemical impedance spectroscopy were used to assess their inhibitive performance, while scanning electron microscopy and energy dispersive analysis examined the morphology of the resulting protective layers.
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Bio-based tannates outperform conventional pigments
The zinc tannates showed strong corrosion inhibition on steel, surpassing the performance of recognised traditional pigments. When incorporated into alkyd primers, the tannates delivered the most significant improvements, enhancing the overall barrier properties of the coating system.
With their renewable origin, low environmental impact and demonstrated effectiveness, Tara-derived zinc tannates meet key requirements for modern green anticorrosive pigments and offer a promising sustainable alternative to conventional additives.
Source: Hadzich, A., Obregón, D., Romagnoli, R., Di Sarli, A. R. & Flores, S., Tannin-rich pigments for improvement of electrochemical properties of anticorrosive paint systems. Journal of Coatings Technology and Research 22, 2351–2369 (2025).
