Electrochemistry and computational mechanisms responsible for the anti-corrosion properties of particular biomolecules on Fe-Cr-Mn alloy in a bio-simulated environment.

The electrochemical performance of the Fe–14Cr–8Mn alloy in physiological fluids was investigated in this study. In simulated body solutions, the capacities of the significant biomolecules tyrosine, tryptophan, and l-histidine to inhibit the corrosion of the alloy were also studied. Scanning electron microscopy, energy dispersive X-ray, and X-ray photoelectron spectroscopy were utilized to investigate the surface morphology and elemental composition of the alloy in various simulated solutions. Potentiodynamic polarization and electrochemical impedance spectroscopy data were used to analyze the electrochemical performance of the alloy. The results showed that the amino acids inhibited the corrosion of Fe–14Cr–8Mn alloy in the simulated body solutions, with maximum inhibitory efficiencies of 55%, 63%, and 70.1% for histidine, tyrosine, and tryptophan, respectively. Quantum chemical computations were also conducted and the findings indicated that even in very aggressive solutions, the alloy had a good passivation capacity. The high stability of the alloy was attributed to the formation of a stable Cr protective film on the alloy surface, which was found to depend on the Cr/Fe oxide ratio. The quantum chemical calculations agreed with the electrochemical results. Tyrosine and l-histidine were effective corrosion inhibitors, but tryptophan protected the solutions better.