Analysis of the Corrosion Inhibition Performance of Amaranthus viridis Extract on SS-410 in 0.5 M HCl and Its...

The present investigation focuses on investigating the Amaranthus viridis L. aqueous extract (AVWE) as a prolonged corrosion inhibitor when applied to the surface of Stainless steel410 (SS-410) in an acidic solution (0.5 M HCl), and the inhibitory efficacy of AVWE was utilised in the formulation of a bio-coating that comprises the AVWE inhibitor along with other additives.

AVWE was prepared by Soxhlet extraction using distilled water as the solvent to selectively isolate polar phytochemicals responsible for corrosion inhibition. The extraction was carried out under reflux for 12 h, employing 400 mL of solvent for 200 g of dried plant material previously dried in a water bath. The obtained semi-solid extract was transferred to a clean vial and preserved in a desiccator for further use. The inhibition efficiency of the AVWE inhibitor was analysed by various techniques, including gravimetric analysis, electrochemical impedance spectroscopy (EIS), UV-visible absorption spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and liquid chromatography mass spectroscopy (LC-MS) analysis. Following the completion of studies on the inhibitory effects of AVWE, a bio-coating was formulated with the AVWE and other additives such as resin, metal oxide, and diluents. ASTM D3359 and durability techniques were used to test the adhesion and sustainability of the formulated coating, respectively.

UV-visible and IR spectroscopy validated the formation of a protective film on the metal surface. Morphological findings obtained from SEM, EDX, and AFM techniques indicated that the addition of the green inhibitor resulted in a reduction in the surface corrosion of SS-410. A gravimetric analysis demonstrated a corrosion inhibition efficiency of 97.22%, whereas electrochemical impedance spectroscopy (EIS) indicated an inhibition efficiency of 95.12% for SS-410 at an inhibitor concentration of 500 ppm in 0.5 M HCl. LC-MS analysis identifies inhibitor phytochemicals that adsorb on metal. ASTM D 3359 and durability test revealed that the formulated coating is environmentally sustainable and protects SS-410 from corrosion.

Stainless steel, the most commonly used engineering material in a wide range of applications, suffers from severe corrosion and gradual deterioration. The effects of corrosion on the economy are widespread and create significant challenges in various sectors. Most of the products used in corrosion mitigation processes are harmful to the environment. Natural inhibitors such as plant extracts and biopolymers are more effective alternatives. These inhibitors are safe, inexpensive, renewable, and eco-friendly. In view of their environmental friendliness and cost-effectiveness, recent investigations have focused on plant-based "green" inhibitors for SS-410 in acidic media (HCl). Electrochemical and surface analyses have demonstrated that Colebrookea oppositifolia extract achieves an inhibition efficiency of 95% for SS410 in 0.5 M HCl, whereas Pouzolzia zeylanica L. extract exhibits an inhibition efficiency of 94.9% under the same conditions. Therefore, AVWE wa Conclusion: The present study proposes a method for employing AVWE, a naturally occurring substance known for its anti-corrosion properties, on stainless steel-410 surfaces. The primary findings indicate that exposure to 0.5 M hydrochloric acid leads to a significant reduction in the corrosion of stainless steel-410 when treated with AVWE. Furthermore, a higher concentration of AVWE demonstrates an enhanced inhibitory effect compared to a lower concentration. The inherent inhibitory properties of AVWE indicate its potential as a promising candidate for the development of environmentally friendly corrosion-resistant coatings.