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Citation:
　Abubakar Muazu,Yaro Shehu Aliyu,Malik Abdulwahab,et al.Sacrificial Anode Stability and Polarization Potential Variation in a Ternary Al-xZn-xMg Alloy in a Seawater-Marine Environment[J].Journal of Marine Science and Application,2016,(2):208-213.[doi:10.1007/s11804-016-1356-8]
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Sacrificial Anode Stability and Polarization Potential Variation in a Ternary Al-xZn-xMg Alloy in a Seawater-Marine Environment

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Title:
Sacrificial Anode Stability and Polarization Potential Variation in a Ternary Al-xZn-xMg Alloy in a Seawater-Marine Environment
Author(s):
Abubakar Muazu1;  Yaro Shehu Aliyu2; 3; 4;  Malik Abdulwahab2; 3;  Abimbola Patricia Idowu Popoola3
Affilations:
Author(s):
Abubakar Muazu1;  Yaro Shehu Aliyu2; 3; 4;  Malik Abdulwahab2; 3;  Abimbola Patricia Idowu Popoola3
1. Department of Mechanical Engineering, Bayero University, Kano P.M.B 3011, Nigeria;
2. Department of Metallurgical and Materials Engineering, Ahmadu Bello University, Zaria P.M.B 1045, Nigeria;
3. Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Pretoria X680, South Africa4. Department of Mechanical Engineering, Ahmadu Bello University, Zaria P.M.B 1045, Nigeria
Keywords:
sacrificial anode; anode efficiency; protection efficiency; polarization potential; intermetallic phase; alloying elements; theoretical current capacity; free electron; seawater; surface films
分类号:
-
DOI:
10.1007/s11804-016-1356-8
Abstract:
In this paper, the effects of zinc (Zn) and magnesium (Mg) addition on the performance of an aluminum-based sacrificial anode in seawater were investigated using a potential measurement method. Anodic efficiency, protection efficiency, and polarized potential were the parameters used. The percentages of Zn and Mg in the anodes were varied from 2% to 8% Zn and 1% to 4% Mg. The alloys produced were tested as sacrificial anodes for the protection of mild steel in seawater at room temperature. Current efficiency as high as 88.36% was obtained in alloys containing 6% Zn and 1% Mg. The polarization potentials obtained for the coupled (steel/Al-based alloys) are as given in the Pourbaix diagrams, with steel lying within the immunity region/cathodic region and the sacrificial anodes within the anodic region. The protection offered by the sacrificial anodes to the steel after the 7th and 8th week was measured and protection efficiency values as high as 99.66% and 99.47% were achieved for the Al-6%Zn-1%Mg cast anode. The microstructures of the cast anodes comprise of intermetallic structures of hexagonal Mg3Zn2 and body-centered cubic Al2Mg3Zn3. These are probably responsible for the breakdown of the passive alumina film, thus enhancing the anode efficiency.

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Memo

Memo:
Received date: 2015-09-14;Accepted date: 2015-12-28。
Corresponding author: Malik Abdulwahab,E-mail:mabdulwahab@abu.edu.ng
Last Update: 2016-07-06