Search
Filters
Close

Investigation of the Electrochemical Behavior of Al-Zn-Bi based Sacrificial Anode in Artificial Seawater

Steel is a common material for the construction of large infrastructures. It is a main constituent used for building of, offshore drilling platforms, steel cast dock, pipeline in seabed, coastal bridges and ship hulls. Corrosion of offshore structures is a serious matter in terms of degradation and deterioration of these structures in a corrosive electrolyte such as seawater, which could lead to fatigue cracks, brittle failure and unstable failure.

Product Number: 51323-19472-SG
Author: Ameeq Farooq, Muhammad Haris Qureshi, Umair Altaf
Publication Date: 2023
$20.00
$20.00
$20.00

In this investigation, the effect of 0.195wt% Bismuth addition on the electrochemical properties of Al-4.22wt%Zn based sacrificial anode in artificial seawater has been evaluated. Al-Zn based sacrificial anodes are widely used for the protection of steel structures against corrosion in marine environment. The electrochemical behavior of Al-4.22wt%Zn-0.195wt%Bi anode and Carbon Steel samples in examined through Metallography, Weight Loss, Open Circuit Potentials (OCP), Electrochemical Impedance Spectroscopy (EIS) and Linear Polarization Resistance (LPR) and the results were analysed. The microstructure of Al-anode showed α-Al matrix, needle like β-AlFeSi intermetallic whereas spherical Bi-particles were uniformly distributed, that promotes uniform dissolution process. OCP of Al-anode and carbon steel shows a potential difference of ~ 400 mV vs. Ag/AgCl implies low voltage sacrificial anode. No inductive loop appeared in EIS curves at low frequency region representing that pitting corrosion of Al-5%Zn is suppressed by Bismuth addition. Resistance of carbon steel reduces continuously, indicating increased corrosion rate with increase in immersion time, moreover, polarization resistance Al-anode is higher than carbon steel, exhibiting ease in anodic dissolution process.

In this investigation, the effect of 0.195wt% Bismuth addition on the electrochemical properties of Al-4.22wt%Zn based sacrificial anode in artificial seawater has been evaluated. Al-Zn based sacrificial anodes are widely used for the protection of steel structures against corrosion in marine environment. The electrochemical behavior of Al-4.22wt%Zn-0.195wt%Bi anode and Carbon Steel samples in examined through Metallography, Weight Loss, Open Circuit Potentials (OCP), Electrochemical Impedance Spectroscopy (EIS) and Linear Polarization Resistance (LPR) and the results were analysed. The microstructure of Al-anode showed α-Al matrix, needle like β-AlFeSi intermetallic whereas spherical Bi-particles were uniformly distributed, that promotes uniform dissolution process. OCP of Al-anode and carbon steel shows a potential difference of ~ 400 mV vs. Ag/AgCl implies low voltage sacrificial anode. No inductive loop appeared in EIS curves at low frequency region representing that pitting corrosion of Al-5%Zn is suppressed by Bismuth addition. Resistance of carbon steel reduces continuously, indicating increased corrosion rate with increase in immersion time, moreover, polarization resistance Al-anode is higher than carbon steel, exhibiting ease in anodic dissolution process.