Assessment of the corrosion inhibition of tin by L-histidine in 3.5 wt% NaCl solution

Abstract This study investigated the corrosion-inhibiting behaviour of L-histidine on tin in a 3.5 wt% NaCl solution using open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and linear polarisation resistance (LPR) techniques. SEM coupled with EDS was employed to examine post-exposure surface morphology and composition, corroborating electrochemical observations. The objective was to elucidate the influence of L-histidine on tin corrosion and assess its suitability as an environmentally friendly inhibitor. EIS showed a marked rise in charge-transfer resistance from 4.99 × 105 to 2.82 × 106 Ω cm2, yielding a maximum inhibition efficiency of 82.27% at 0.05 M, indicating enhanced surface protection with increasing inhibitor concentration. SEM-EDS identified L-histidine-derived species on the tin surface, supporting adsorption-driven film formation consistent with the electrochemical response. The inhibition mechanism is attributed to adsorption via imidazole and amino groups, forming a stable protective layer that impedes corrosion processes.