Electron transfer by thiourea-based compounds as eco-friendly corrosion inhibitors on Al alloy for long-term corrosion response F. Hazmatulhaq, A. Chaouiki, Y. G. Ko*
Materials Electrochemistry Group, School of Materials Science and Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea
Abstract
The present work reports the role of electron donor-acceptor behavior in thiourea-based corrosion inhibitor on enhancing the protective performance of Al alloy subjected to plasma electrolysis (PE). To this end, the PE-treated Al alloy was exposed to NaCl solutions containing thiourea-based compounds in long-term immersion to evaluate the effect of corrosion inhibitor on its morphological structure. A uniform plate-like layer identified as metal-organic complex was observed covering the surface of the PE-treated Al alloy, leading to the inhibition of corrosion during immersion. The mechanism underlying corrosion inhibition was evaluated by density functional theory (DFT) calculation. It was found that the heteroatoms along with benzene ring act as an adsorption sites which facilitate the electron transfer with PE-treated Al alloy via intermolecular interactions. As a results, the synergy between adsorbed thiourea and PE-treated Al surface plays a pivotal role in the formation of stable metal-organic complex responsible for excellent corrosion resistance.
Keywords: Al alloy, plasma electrolysis, corrosion inhhibitor, electron transfer, corrosion resistance
