The anti-corrosion performance of chaya leaf extracts on pure Mg substrates in Ringer´s solution

Abstract

The chaya (Cnidoscolus aconitifolius) is a green, leafy vegetable domesticated since ancient Mayan culture, offering an abundance of valuable metabolites. This study investigated how three different extracts from Chaya leaves inhibit the corrosion of pure magnesium in Ringer's solution. Various techniques, such as scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction were employed to analyze the chemical, morphological, and structural aspects of the products formed on the magnesium surface after a 14-day exposure. The in vitro corrosion behavior was studied through open-circuit potential measurements and electrochemical impedance spectroscopy during immersion tests in physiological Ringer's solution with each extract. Polarization curves were also obtained to determine jcorr and Ecorr. Different morphologies were observed on the surfaces of the substrates due to each extract’s polarity. However, the results showed that the three chaya extracts retard, to some extent, the corrosion process, reducing the pH (from 9 to 6) and jcorr (from 18.2 to 1.12 µAcm−2) in comparison to untreated samples. The ethyl acetate-derived extract exhibited the highest percentage of inhibition (92.9%) according to the impedance results. These extracts could be a promising alternative for developing potential temporary implants for the human body and diverse industrial applications.