Corrosion inhibition performance of Glycyrrhiza glabra extract for 6061 aluminium alloy in acidic solution

The corrosion inhibition behavior of Glycyrrhiza glabra (GG) extract on 6061 aluminum alloy in 1 M HCl solution was examined using electrochemical polarization techniques and scanning electron microscopy (SEM). The findings revealed that the GG extract effectively reduced the corrosion rate of 6061AA in the acidic medium. An inhibition efficiency of approximately 90.3% was obtained at an inhibitor concentration of 200 ppm and 298 K. The inhibition efficiency increased with increasing inhibitor concentration and decreased with increasing temperature. Adsorption of GG molecules on the aluminum surface was found to follow the Langmuir adsorption isotherm. Thermodynamic parameters were evaluated to clarify the inhibition mechanism. Polarization measurements indicated that the extract behaves as a mixed-type inhibitor. SEM observations confirmed the formation of a protective layer on the metal surface in the presence of the inhibitor.