Nano SiC-Reinforced AA7178 Matrix Alloy: Corrosion Behavior and Characterization

The primary objective of this study was to assess the impact of incorporating SiC on both the microstructure and corrosion characteristics of nanocomposites based on the AA7178 matrix alloy. The fabrication of AA7178 alloy reinforced with SiC composites was achieved through a stir-casting technique, with SiC reinforcement levels varying from 0 to 3 wt.% in 1% increments. Scanning electron microscopy analysis indicated a consistent distribution of SiC nanoparticles throughout the aluminum matrix. To evaluate the electrochemical behavior, investigations were conducted employing open-circuit potential (OCP), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) in a 3.5% sodium chloride solution. The findings from the polarization and EIS analyses demonstrated that the corrosion resistance of the nanocomposites exceeded that of the base matrix alloy. This improvement in corrosion resistance was attributed to the electrochemical decoupling observed between SiC particles and the AA7178 matrix alloy. Notably, the nanocomposite with a SiC content of 3 wt.% (AA7178/3wt.% SiC) exhibited the most significant corrosion resistance, characterized by optimal values for current density corrosion (0.03443 mA/cm 2 ) and potential corrosion (-0.15144 V). Furthermore, examination with scanning electron microscopy (SEM) indicated that pitting and cracks were the primary mechanisms contributing to corrosion in these materials.