Potential of rare-earth compounds as anticorrosion pigment for protection of aerospace AA2198-T851 alloy
Shedrack Musa Gad, Zelong Jin, Seyedgholamreza Emad, Javier Espinoza Vergara, Danjuma Saleh Yawas, Ishaya Musa Dagwa, Ibrahim Momoh‐Bello Omiogbemi
Abstract
In this study, the anticorrosion potential of carboxylic compounds; Lanthanum 4-hydroxycinnamate La(4OHCin) 3 , Cerium 4-hydroxycinnamate Ce(4OHCin) 3 and Praseodymium 4-hydroxycinnamate Pr(4OHCin) 3 for the protection of Al–Cu–Li alloy was investigated in 3.5% NaCl solution using electrochemical tests (EIS and PDP), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The findings achieved show a very good correlation between electrochemical responses and surface morphologies of the exposed alloy, indicating a modification of the surface by precipitation of the inhibitor species, leading to effective protection against corrosion. At optimum concentration 200 ppm, the trend of inhibition efficiency η (%) increases in the order Ce(4OHCin) 3 93.35% > Pr(4OHCin) 3 85.34% > La(4OHCin) 3 82.25%. XPS complemented the findings by detecting and providing information about the oxidation states of the protective species.