Corrosion resistant linseed oil-based ceramer coatings

Electrochemical impedance measurements were conducted on linseed oil-based ceramer coatings on aluminum panels immersed in 3% NaCl solution for 180 days. Electrochemical impedance spectroscopy was used to evaluate the corrosion resistance of the ceramer coatings as a function of sol-gel precursor content. The ceramer coatings were developed using linseed oil as the organic phase and titanium i-propoxide and zirconium n-propoxide as the sol-gel precursors. The ceramer coatings containing 5 wt% titanium i-propoxide or zirconium n-propoxide provided excellent barrier protection and maintained a resistance greater than 1 x 109 ohms in the low frequency range (f = 0.01 Hz) throughout the study. As an extension to this study, 0.5-1 wt% zinc acetate dihydrate was added as an anticorrosive agent to linseed oil with 5 and 10 wt% titanium i-propoxide. The incorporation of zinc acetate dihydrate dramatically increased the impact resistance while maintaining flexibility. Surprisingly, the incorporation of zinc acetate dihydrate initially decreased the modulus but maintained an initial resistance of 1 x 10(8) ohms for 180 days.