Thiocarbohydrazide-crosslinked chitosan as a bioinspired corrosion inhibitor for protection of stainless steel in 3.5% NaCl

A facile single-step synthesis was performed to cross-link chitosan with thiocarbohydrazide to yield thiocarbohydrazide-chitosan (TC-Cht) which was for the first time evaluated as an inhibitor for corrosion of stainless steel in 3.5% NaCl solution. A comprehensive electrochemical analysis employing electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and cyclic voltammetry (CV) was undertaken and showed that the TC-Cht acts by adsorption on the steel surface and exhibits mixed type behavior with predominantly cathodic nature. The adsorption of TC-Cht molecules on the surface of stainless steel followed the Langmuir isotherm. The TC-Cht showed a high inhibition efficiency of >94% at 500 mg L^?1 concentration. Surface investigation using SEM and EDX supported the inhibitor adsorption on the steel surface.