Synergistic effect of 2-oleyl-1-oleylamidoethyl imidazoline ammonium methylsulfate and halide ions on the inhibition of mild steel in HCl

► We study the synergistic inhibition mechanism by molecular dynamics simulation. ► We study the inhibition performance from the aspect of corrosive particle diffusion. ► Synergistic inhibition mechanism was revealed by FFV and diffusion coefficient.