Study On The Inhibition Mechanism Of Organic Corrosion Inhibitor In Epoxy Coatings

Corrosion inhibition of 1, 4- butynediol in epoxy coatings was studied by means of electrochemical method and DSC. Experimental results showed that the inhibitor obviously increase the corrosion-resistance of epoxy coatings. When the amount of 1, 4- butynediol corrosion inhibitor is less than 0.5 % in the coating, the impedance of coating increases with addition of the corrosion inhibitor. Through the impedance data that is fitted by Zsimpwin software, we suggest that the incomplete corrosion inhibitor film with double bonds is formed between coating and substrate. The inhibitor mechanism of the corrosion inhibitor film was also discussed by means of electrochemical method.By means of electrochemical impedance spectroscopy (EIS) and surface analysis technology, the impedance variation of epoxy coatings with talcum powder filler coated by various organic corrosion was studied .The diffusion coefficients of water through epoxy coatings with talcum powder filler coated by different concentration stearic acid was calculated .The experimental results show that the stearic acid -coated talcum powder filler in the epoxy coatings has the function of decreasing water diffusion coefficients , and modifying filler by coating is likely to be a method to make the filler with anti-corrosion function . Furthermore, the filler coated by stearic acid have a optimum coating concentration, when less than the concentration, diffusion coefficients decrease with coating concentration increase, while more than the concentration, the filler influences adhesion between the coating and substrate, as a result, stearic acid can cause the failure of corrosion protection. The permeability of water vapor through epoxy coatings with talcum powder coated by stearic acid was measured by permeation cup, the permeation apparent activation energy was calculated .The experiment results show the water vapor permeability increased with increasing temperature however, water saturated absorption changed very little. The permeation apparent activation energy of water vapor through epoxy coating with stearic acid is obviously higher than that through epoxy coating without stearic acid.