Potentiodynamic and electrochemical impedance spectroscopy analysis of hybrid metallic systems in 1 M HCl

¹ Centre for Nanoengineering and Advanced Materials (CeNAM), School of Mining, Metallurgy and Chemical Engineering, University of Johannesburg, Johannesburg, 2092, South Africa
² Department of Chemical and Materials Engineering, University of South Africa, P.O. Box 392, Florida 1709, South Africa
³ Department of Mechanical and Mechatronic Engineering, Cape Peninsula University of Technology, Cape Town, South Africa.
⁴ Department of Mechanical and Industrial Engineering, University of Johannesburg, Doornfontein Campus, Johannesburg 2028, South Africa

^* Corresponding author: samsoniumdare@gmail.com

Abstract

This study evaluates the corrosion performance of hybrid aluminium components comprising built and substrate regions. The hybrid system, developed via additive and subtractive methods, was divided to separate individual parts for microstructural and electrochemical analysis in 1 M HCl using Open Circuit Potential (OCP), Electrochemical Impedance Spectroscopy (EIS), Potentiodynamic Polarization (PDP), and Chronoamperometry were used to assess corrosion kinetics, passive film stability, and time-dependent degradation. Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDS) was used to characterize surface morphology before and after corrosion, identifying phase distribution and localized corrosion. The results pinpoint the electrochemical differences between two hybrid configurations - Sample E (Al 7 built on 6082 substrate) and Sample F (Al 10 built on 6082 substrate), with one typical configuration (Sample E) exhibiting superior corrosion resistance across both its built and substrate regions due to a more stable passive layer and refined microstructure.