Pyrimidine derivative as eco-friendly corrosion inhibitor for nickel−aluminum bronze in seawater

A pyrimidine derivative, 6-phenyl-2-thiouracil (PT), was synthesized for developing a corrosion inhibitor (CI) applied in the protection of the nickel−aluminum bronze (NAB) in seawater. The anti-corrosion effect of PT was evaluated by the mass loss experiment, electrochemical tests and surface analysis. The results show that PT exhibits excellent inhibition performance and the maximum inhibition efficiency of PT reaches 99.6%. The interaction mechanism was investigated through X-ray photoelectron spectroscopy (XPS) and molecule dynamics simulation based on the density functional theory (DFT). The S—Cu, Al—N and Cu—N bonds are formed by the chemical interactions, leading to the adsorption of PT on the NAB surface. The diffusion of corrosive species is hindered considerably by the protective PT film with composition of (PT—Cu)_ads and (PT—Al)_ads on the PT/NAB interface. The degree of suppression is increased with the addition of more PT molecules.