Effects of Inorganic Metabolites of Sulphate-Reducing Bacteria on the Corrosion of AZ31B and AZ63B Magnesium Alloy in 3.5 wt.% NaCl Solution

Jinrong Li; Xin Liu; Jie Zhang; Ruiyong Zhang; Mingxing Wang; Wolfgang Sand; Jizhou Duan; Qingjun Zhu; Shenbao Zhai; Baorong Hou

doi:10.3390/ma15062212

Effects of Inorganic Metabolites of Sulphate-Reducing Bacteria on the Corrosion of AZ31B and AZ63B Magnesium Alloy in 3.5 wt.% NaCl Solution

Materials (Basel). 2022 Mar 17;15(6):2212. doi: 10.3390/ma15062212.

Authors

Jinrong Li^{1

2

3}, Xin Liu^{2

3}, Jie Zhang^{1

3}, Ruiyong Zhang^{1

3}, Mingxing Wang^{1

3}, Wolfgang Sand^{4

5

6}, Jizhou Duan^{1

3}, Qingjun Zhu^{1

3}, Shenbao Zhai⁷, Baorong Hou^{1

3}

Affiliations

¹ Key Laboratory of Marine Environmental Corrosion and Biofouling, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
² College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
³ Open Studio for Marine Corrosion and Protection, Pilot National Laboratory for Marine Science and Technology, Qingdao 266273, China.
⁴ Institute of Biosciences, University of Mining and Technology, 09599 Freiberg, Germany.
⁵ Department of Aquatic Biotechnology, University of Duisburg-Essen, 45141 Essen, Germany.
⁶ Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai 200051, China.
⁷ Zibo Deyuan Metal Material Co., Ltd., Zibo 200051, China.

Abstract

This study seeks prevent and alleviate the failure of magnesium alloy anodes in pipelines, which we suspect is a problem related to SRB. The electrochemical corrosion behaviour of two kinds of magnesium alloys, AZ31B and AZ63B, in 3.5 wt.% NaCl solution with sulphide or phosphide-the two main inorganic metabolites of sulphate-reducing bacteria-were studied by electrochemical tests combined with other characterisation methods such as scanning electron microscopy and X-ray diffraction. The results show that the corrosion film formed by inorganic metabolites of SRB's initial stage of corrosion (1-3 d) can lead to the corrosion of magnesium alloys. However, the loose and porous corrosion product film cannot protect the substrate effectively. The inorganic metabolites in the solution can accelerate the corrosion of the surface of magnesium alloy after the corrosion products have fallen off. This study provides a theoretical basis for alleviating the premature failure of magnesium alloy anodes and for corrosion protection in the future.

Keywords: corrosion; electrochemical impedance spectroscopy; inorganic metabolites; magnesium alloy; sulphate-reducing bacteria.