Rapid electrochemical evaluation of corrosion resistance in TiO 2 /polyurethane composite coatings

Polyurethane is widely used coating to prevent corrosion. Incorporating nanoparticles into composite coatings has been explored to improve polyurethane barrier properties and prolong service life. In this study, an accelerated cyclic electrochemical technique (ACET) was developed and applied as a rapid evaluation method for evaluating the corrosion protection performance of nanoparticle-reinforced polyurethane coatings. Electrochemical characterization was conducted in 3.5 wt.% NaCl solution. TiO 2 /Polyurethane composite coatings with 1–5 wt% TiO 2 were evaluated. Coating performance was correlated with water contact angle measurements, scanning electron microscopy (SEM), and pull-off adhesion testing. Results showed that adding 1–3 wt% TiO 2 improved polyurethane barrier properties. The 3 wt.% TiO 2 composite exhibited the highest coating resistance and corrosion protection performance. The enhanced performance was attributed to the barrier effect of well-dispersed TiO 2 nanoparticles, which reduced coating porosity and improved coating hydrophobicity, thereby limiting water and electrolyte penetration. In contrast, the 4 −5 wt% composites showed little or no improvement because of the coating cracking and particle agglomeration caused by excessive TiO 2 loading. These findings demonstrate the effectiveness of ACET as a rapid screening tool for evaluating protective coating systems and identify an optimal TiO 2 loading range for improving the corrosion protection performance of polyurethane coatings.