THE CORROSION INHIBITION OF ALKYL IMIDAZOLINE ON CARBON STEEL IN AMIDOSULPHURIC ACID SOLUTION

2-undecyl-N-carboxymethyl-N-hydroxyethyl imidazoline(UHCI) was investigated as a corrosion inhibitor for carbon steel in 8 mass%amidosulphuric acid solution using weight loss test,electrochemical methods and scanning electron microscopy(SEM).The weight loss test results showed that the inhibitor was an excellent inhibitor for carbon steel in acid media with an inhibition efficiency of 90.12%and a corrosion rate of 0.6370 g/(m~2·h) at the mass fraction of 0.4%.The polarization curves indicated that the inhibitor behaved as a mixed type inhibitor.The impedance spectra of carbon steel electrodes changed from one time constant into two time constants when the inhibitor added into the blank solution.The absorption of the inhibitor was found to follow the Langmuir adsorption isotherm and the mechanism was a mixture of chemisorption to physisorption. The results from SEM also give evidence of the effective inhibition of UHCI on carbon steel corrosion in amidosulphuric acid.