The quaternary ammonium salts as corrosion inhibitors for X65 carbon steel under sour environment in NACE 1D182 solution: Experimental and computational studies

The effect of quaternary ammonium salts (DDPC and DDQC) with different concentrations on the corrosion inhibition of X65 carbon steel in the sour brine solution at different temperatures were investigated by weight loss, electrochemical measurements, surface analysis (SKP, AFM, SEM, EDS, and ATR-FTIR), and theoretical calculations (DFT, Monte Carlo, and molecular dynamics). It was found that the corrosion rate decreased with increasing inhibitor concentration, and the inhibition efficiency was about 98%. The adsorption of inhibitors on the metal surface followed the Langmuir adsorption isotherm. Furthermore, inhibitors showed good performance at elevated temperatures. The computational studies supported the experimental data well.