Research on 1,10-phenanthroline quaternary ammonium salt composite corrosion inhibitors for oilfield acidizing at high temperatures and high HCl concentrations

1-Benzyl-1,10-phenanthrolin-1-ium bromide (PQBr) was synthesized as a corrosion inhibitor for N80 steel, and its corrosion inhibition at high temperatures and high HCl concentrations was investigated via the weight-loss method. The addition of PQBr other additives reduced the corrosion rate of N80 carbon steel in 20% HCl at 453 K and 3 MPa to 59.93 g·(m2·h)−1. The adsorption of PQBr onto the surface of N80 carbon steel was evaluated by SEM, EIS, and PDP. An adsorption model and kinetic parameters of PQBr had been generated and determined. DFT calculations were performed to analyze the effect of the PQBr structure on adsorption.