Study Of Corrosion Inhibitory Property Of Benzotriazole And Compound Corrosion Inhibitors On Brass In Seawater

Benzotriazole (BTA) is an effective and normal inhibitor in preventing the corrosion of copper and its alloys in industry. However, the deficiencies of BTA are its toxicity and bad water solubility. In order to reduce the influence on the environment, the synergistic effect and the order of adding inhibitors between BTA and KI were discussed.The inhibition efficiency and the influence factors of the experiment were studied by weight loss method. The results show that the maximum inhibition efficiency is 99.28% with 100mg/l single BTA. The inhibition efficiency reaches to 97.19% with the concentration of BTA and KI being 2mg/l and 10mg/l respectively. The inhibition efficiency is improved greatly that reaches to 99.31% with the order of adding inhibitors. The experiment of the influence factors show that the compound inhibitor can be applied to the water, the temperature of which is lower than 40℃, neutral or slightly basic environment. It has a good adaptability to the non-oxidizing bactericides and a good chlorine resistant.The inhibition effects of the compound inhibitor were tested by potentiodynamic polarization method and AC impedance technique. Polarization curves show that the compound inhibitor is a kind of cathodic-type inhibitor for brass in seawater. Impedance tests show that the compound inhibitor decreases the corrosion rate by increasing the charges transfer resistance of metal surface.The results of energy dispersive X-ray spectroscopy (EDS) and solution analysis show that the compound inhibitor suppresses the dezincification corrosion efficiently and I- plays a role in repairing the film.The results of X-ray photoelectron spectroscopy(XPS) show that the peak of Cu2p shifts to the higher binding energy region arising from increasing content of Cu(I) with the addition of the compound inhibitor, which indicates the formation of passive film containing Cu2O, CuCl and Cu(I)-BTA.The results of scanning electro microscope(SEM) images show that the blank is corroded heavily. The metal surface with adding only BTA (2mg/l) has a large number of pitting corrosion. No significant corrosion occurs on the metal surface with adding 2mg/l BTA and 10mg/l KI. After adding the inhibitor in the order, the metal surface is brighter with more notable films that will be conductive to the protection of brass.