Synthesis of watermelon seed extract and silica nanocomposites coatings and their utilization for the corrosion prevention of mild steel in saline solutions
Yashasvi Jaiswal, Chandresh Kumar Rastogi, Chandresh Kumar Rastogi, C. Manjunatha, Gopal Ji, Gopal Ji
Abstract
This study aims to investigate corrosion behaviors of watermelon seed chloroform extract (WMSE) coated-mild steel (MS) in saline environments. Additionally, silica nanoparticles (SNPs) have been added into WMSE coatings in two different ratios (forming WMSESNC) and investigated for its protective performance. WMSE has been characterized by Fourier transform infrared spectroscopy (FTIR), which has confirmed the presence of bioactive molecules in WMSE. SNPs are investigated by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDAX), before their addition in WMSE. Coatings of WMSE and WMSESNC have been made on MS's surface by drop casting (DC) using 50 μL of them for 1 layer. Corrosion resistance of bare and coated MS in a 0.5 M NaCl solution have been evaluated by open circuit potential (OCP), Tafel polarization (TP), and electrochemical impedance spectroscopy (EIS). The results indicate that WMSE (100 μL-2 Layer) alone achieves the highest corrosion prevention efficiency of 68%, while the addition of SNPs reduces the efficiency to 54%. This unexpected decrease suggests that SNPs interfere with the uniform adsorption of WMSE molecules on the MS surface, compromising corrosion resistance. This research contributes to the advancement of cost-effective and environmentally friendly solutions for corrosion prevention in saline environments.