Robust corrosion protection of Ni-thiolate coordination polymer/Mg(OH)2 coating on magnesium alloy AZ31

Although magnesium alloys have been effectively used in industry, they have weak corrosion resistance. Herein, robust Ni-thiolate coordination polymer Mg(OH)(2) coatings were prepared by an oxidation-hydrolysis-coordination (OHC) strategy to make AZ31 magnesium alloy highly resistant to corrosion in 3.5 wt% NaCl solution. The OHC process includes three steps: I) oxidation of AZ31 to produce AZ31@MgO; II) hydrolysis of MgO to produce Mg(OH)(2), cation exchange between Mg(OH)(2) and Ni(II) to produce MgeNi LDH; III) coordination of Ni(OH)(2) fromMgeNi LDH by the 1,4-Benzenedithiol (BDT) ligand to produce LDH-BDT coatings. Potentiodynamic polarization, EIS, and in situ SRET in 3.5 wt% NaCl solution were used to assess the hybrid coating's anti-corrosion performance. Surprisingly, LDH-BDT coating achieves excellent corrosion inhibition performance (99.9999%) with the icorr of 1.926 x 10(-1)0 A cm(-2) which is six orders of magnitude lower than that of AZ31 substrate, this is due to the cooperative effect, such as the physical protection provided by thick LDH-BDT coatings and the hydrophobic properties of Ni(II)-BDT coordination polymers. This study provides fresh insight into the fabrication of Mg(OH)(2)-based coatings modified with Ni-thiolate complex to significantly improve Mg alloys' resistance to corrosion. (c) 2023 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

A robust Ni-thiolate coordination polymer Mg(OH)(2) coating was prepared for AZ31 magnesium alloy to enhance its corrosion resistance. The hybrid coating showed excellent corrosion inhibition performance due to the physical protection provided by the thick coating and the hydrophobic properties of the coordination polymers.