Insight into the anti-corrosion performance of three imidazo-pyridazines for Al alloy in different concentrations of hydrochloric acid solutions

Imidazo-pyridazine and Bromo/Chloro-Imidazo-pyridazines are employed as the inhibitors for Al alloy in 0.1 M HCl and 0.5 M HCl solutions. The electrochemical tests and adsorption model analysis revealed that three compounds are mixed-type inhibitors and Imidazo-pyridazine exhibited the best anti-corrosion performance for Al electrode in HCl solutions by physicochemical. From electrochemical results, the best anti-corrosion efficiency is 88.1 % for Al in 0.5 M HCl with 2.0 mM IP, while the efficiency is 75.5 % for Al in 0.5 M HCl with 1.0 mM IP. The different inhibition behaviors result from the probability of the formation of AlCl - ads and N-onium ions. The formation of adsorption is due to the electrostatic attraction between AlCl - ads and N-onium ions. The surface topography test revealed that the Imidazo-pyridazine is the best corrosion barrier for Al in 0.5 M HCl. The dynamic simulation demonstrated that the inhibition molecules and protonated molecules can adsorb on the Al surface spontaneously with parallel adsorption configuration no matter in more or less Cl - atmosphere.