Corrosion behavior analysis and characterization of AA7178 matrix alloy reinforced with nano TiO₂ particles

Abstract

The objective of this study is to assess how AA7178 matrix-based nanocomposites’ microstructure and corrosion properties are affected by the addition of nano TiO2 particles. The AA7178 alloy reinforced TiO2 composites were manufactured via stir-casting, with the TiO2 reinforcement levels ranging from 0% to 3% by 1% increments. A uniform distribution of TiO2 nanoparticles(2 wt%) over the Al matrix was shown by scanning electron microscopy analysis. The electrochemical behaviour of the base alloy matrix and surface composites was thoroughly investigated in a solution containing 3.5% sodium chloride utilizing open-circuit potential (OCP), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). Research using polarization and EIS showed that the nanocomposites were more resistant to corrosion than the matrix alloy. Subsequent examination indicated that the increased resistance to corrosion observed in the composites containing TiO2 particles might be a result of electrochemical decoupling between the AA7178 matrix alloy and the TiO2 particles. In order to stop the corrosion from spreading, this decoupling action is vital since it protects the TiO2 particles from the matrix alloy. The composite material AA7178/2 wt% TiO2 showed the best corrosion resistance, with ideal values for potential corrosion (−0.20622 V) and current density corrosion (0.00344 mA cm−2). The main causes of corrosion were shown to be pitting and cracking by scanning electron microscopy (SEM) study, highlighting the usefulness of TiO2 in reducing these negative impacts. This work illuminates the corrosion behaviour of AA7178/TiO2 nanocomposites and emphasizes the importance of electrochemical decoupling in improving the corrosion resistance of advanced materials.