Synthesis of ethanol extract of rose petal and its coating on mild steel for corrosion prevention in sodium chloride solutions

Rose petal (RP) extract, a natural and sustainable material, was investigated as a corrosion-inhibiting coating for mild steel (MS) in 0.5 M NaCl. The extract was prepared using ethanol and characterized by FTIR and UV–visible spectroscopy, confirming the presence of bioactive functional groups. One- and two-layer coatings were applied on MS via the drop-casting method. Corrosion performance was assessed using open circuit potential (OCP), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS). PDP results showed inhibition efficiencies of 86% for single-layer (R1) and 91% for double-layer (R2) coatings, while EIS indicated 92% for R1 and 96% for R2. Surface analyses using optical microscopy and AFM confirmed improved protection and reduced surface roughness for coated samples. Overall, double-layer RP extract coatings effectively enhance the corrosion resistance of MS in chloride-containing environments, demonstrating their potential as eco-friendly corrosion inhibitors.