Evaluation of MgAl LDH incorporated Gallic acid anti-corrosion impact on mild steel in tempered 3.5% NaCl solutions: Integrated electrochemical and morphological studies

Abstract

Undoubtedly, high temperature is one of the most risk factors that aggravate corrosion, which can greatly affect the lifespan of metal substrates. Hence, high temperature corrosion control now become one of the exciting research hotspot for researchers. For corrosion prevention, the application of corrosion inhibitors is one of the easy and practical ways and with the emergence of nanomaterials, smart inhibitors has been remarked as a milestone in corrosion science. In this study, layered double hydroxide (LDH) nano-carrier encapsulated gallic acid (GA) was applied to control steel corrosion in high temperature 3.5% NaCl saline environment. The structural evaluation of this nanocomposite has been done with the help of X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Brunauer-Emmett-Teller (BET) tests and the results have confirmed the successful synthesis of this nanocomposite. Then, polarization test predicted the inhibition mechanism and the results shown the mixed inhibition is responsible for 68% and 60% of corrosion controlled in 35° and 45° environment, respectively. But in order to better evaluation, the performance of the nanocomposite has been checked via electrochemical impedance spectroscopy (EIS) evaluations. Based on the studies, it has been found that high temperature has severely limited the performance of the pristine GA, but LDH/GA nanocomposite has been able to achieve 72% efficiency at 35 °C and 58% efficiency at 45 °C. Finally, Field emission scanning electron microscopy (FE-SEM) captures aided to assess the morphology of immersed surfaces at different temperatures and Energy Dispersive X-Ray Analysis (EDX)/MAP tests estimated the elemental structure of the samples.