Evaluating the corrosion behavior of 6061 Al-10(vol.%) SiC(P) composite in varied HCl concentration using ionic liquid: electrochemical and surface studies

The corrosion behaviour of 6061 Al-10(vol.%) SiC_(P) composite in hydrochloric acid (HCl) was studied. Studies were done in 0.01 and 0.025 M HCl using 1-methyl-1-propyl piperidinium bromide (MPPB) as a green inhibitor. Potentiodynamic polarisation (PDP) and electrochemical impedance spectroscopy (EIS) were conducted at the temperature range of 303 K–323 K. Kinetic parameters were calculated and results were fitted into suitable adsorption isotherms. Adsorption/desorption equilibrium constant was used to evaluate, the thermodynamic parameters. Surface analysis was done by different methods such as scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), and atomic force microscope (AFM). The highest efficiency was found to be 77.49% in 0.01 M HCl and 72.89% in 0.025 M HCl for 400 ppm of inhibitor at 303 K. As the concentration of acid increased, inhibition efficiency decreased. Inhibitor acted as a mixed type, adsorbed physically onto the metal surface, and followed Langmuir adsorption isotherm.