Robust composite coating with superior corrosion inhibitory performance on surgical grade 316L stainless steel in Ringer solution

Abstract

316L stainless steel (SS) is used as an orthopedic implant biomaterial due to its properties such as superior tensile strength, fatigue strength, and fracture toughness. Although it possesses such remarkable properties, it is corroded in aggressive biofluids. Hence, with a view to combat corrosion of surgical grade 316L SS, 3-amino-5-mercapto-1,2,4-triazole (AMTa) and its Na-montmorillonite (Na-MMT) K10 clay composite were electropolymerized over its surface and its anti-corrosion performance was evaluated. The results of electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies (PDS) revealed the enhanced protective behavior of the composite compared to the polymer which was guaranteed by the results of chronoamperometric studies and atomic absorption spectroscopy. The functionalities of electrochemically synthesized p-AMTa and its Na-MMT composite films were characterized by Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy results which supported the formation of the polymer by NH–NH and S–S linkages. The surface morphological studies of a bare and film-deposited 316L SS confirmed the protective layer formed over the SS surface. Further, the effect of concentration of monomer and Na-MMT on corrosion inhibition was also studied. Anticorrosive performance of the polymer and Na-MMT composite studied after 7 days of immersion in the Ringer solution revealed that composite-coated 316L SS could retain its protective performance.