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Effects of Al 3+ concentration in hydrothermal solution on the microstructural and corrosion resistance properties of fabricated MgO ceramic layer on AZ31 magnesium alloy
Author(s) -
Wang Zhihu,
Zhang Jumei,
Bai Lijing,
Zhang Guojun
Publication year - 2021
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.202011948
Subject(s) - materials science , corrosion , ceramic , hydrothermal circulation , magnesium , magnesium alloy , alloy , hydroxide , composite number , oxide , metallurgy , electrochemistry , layer (electronics) , chemical engineering , composite material , electrode , chemistry , engineering
Abstract Porous magnesium oxide (MgO) ceramic layers were prepared on AZ31 magnesium alloy via microarc oxidation (MAO) and sustained hydrothermal treatment at 90°C for 18 h in alkaline zinc nitrate solution with varying Al 3+ concentrations. Increasing the Al 3+ concentration advanced the formation of layered double hydroxide (LDH) films on the MgO ceramic layers, enabling the sealing of micropoles and cracks via in situ growing. Electrochemical and immersion test results indicated that the MAO/hydrothermal treatment‐prepared LDH/MgO composite coatings achieved increased corrosion resistance than single MAO ceramic layers, due to the sealing effect and ion‐exchange capacity of LDHs. Furthermore, as Al 3+ concentration in hydrothermal solution increased, the anticorrosion properties of the composite coatings were enhanced. Concludingly, LDH/MgO composite coatings could provide augmented long‐term anticorrosion protection for magnesium alloys compared with single MAO ceramic layers.