The Corrosion Behavior of AZ91D Magnesium Alloy in Simulated Haze Aqueous Solution

Liying Cui; Zhiyong Liu; Peng Hu; Jiamin Shao; Xiaogang Li; Cuiwei Du; Bin Jiang

doi:10.3390/ma11060970

The Corrosion Behavior of AZ91D Magnesium Alloy in Simulated Haze Aqueous Solution

Materials (Basel). 2018 Jun 8;11(6):970. doi: 10.3390/ma11060970.

Authors

Liying Cui^{1

2}, Zhiyong Liu^{3

4}, Peng Hu⁵, Jiamin Shao^{6

7}, Xiaogang Li^{8

9

10}, Cuiwei Du^{11

12

13}, Bin Jiang¹⁴

Affiliations

¹ Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083, China. s20161333@xs.ustb.edu.cn.
² Key Laboratory for Corrosion and Protection (MOE), University of Science and Technology Beijing, Beijing 100083, China. s20161333@xs.ustb.edu.cn.
³ Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083, China. liuzhiyong7804@ustb.edu.cn.
⁴ Key Laboratory for Corrosion and Protection (MOE), University of Science and Technology Beijing, Beijing 100083, China. liuzhiyong7804@ustb.edu.cn.
⁵ Key Laboratory of Environment Fracture Ministry of Education, University of Science and Technology Beijing, Beijing 100083, China. s20161346@xs.ustb.edu.cn.
⁶ Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083, China. s20161372@xs.ustb.edu.cn.
⁷ Key Laboratory for Corrosion and Protection (MOE), University of Science and Technology Beijing, Beijing 100083, China. s20161372@xs.ustb.edu.cn.
⁸ Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083, China. lixiaogang@ustb.edu.cn.
⁹ Key Laboratory for Corrosion and Protection (MOE), University of Science and Technology Beijing, Beijing 100083, China. lixiaogang@ustb.edu.cn.
¹⁰ State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China. lixiaogang@ustb.edu.cn.
¹¹ Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083, China. dcw@ustb.edu.cn.
¹² Key Laboratory for Corrosion and Protection (MOE), University of Science and Technology Beijing, Beijing 100083, China. dcw@ustb.edu.cn.
¹³ State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China. dcw@ustb.edu.cn.
¹⁴ College of Materials Science and Engineering, Chongqing University, Chongqing 400030, China. jiangbinrong@cqu.edu.cn.

Abstract

The corrosion process of AZ91D magnesium alloy in simulated haze aqueous solution has been studied by electrochemical measurements, immersion tests and morphology characterization. Results show that AZ91D was corroded heavily in simulated haze aqueous solution due to the loose and breakable product film on the surface providing little corrosion barrier. The effect of different ions was investigated. It was found that both N O 3 − and N H 4 + played an important role in the corrosion process. N O 3 − helped to form passive film to protect the matrix, yet N H 4 + consumed OH^−, resulting in the absence of Mg(OH)₂ and serious corrosion. Meanwhile, S O 4 2 − and Cl^− had influence on pitting corrosion. Magnesium aluminum oxide and MgAl₂(SO₄)₄·22H₂O instead of Mg(OH)₂ were the dominate products, which is different from the former study. Corrosion rate changed with time, especially in the first 3 h. A two-stage corrosion mechanism is proposed after considering both the corrosion process and the influence of ions.

Keywords: EIS; SEM; magnesium; pitting corrosion.