Enhancement of corrosion resistance of AZ31 Mg alloys by one-step in situ synthesis of ZnAl-LDH films intercalated with organic anions(ASP, La)

Inserting corrosion inhibitors into a lamellar protective coating is an effective way to improve the corrosion resistance of metal substrates.In this work,two kinds of environmentally friendly organic acid anions,aspartic acid(ASP)and lauric acid(La),were explored as corrosion inhibitors to in situ intercalate into the Zn Al-layered double hydroxides(Zn Al-LDHs)on AZ31 magnesium alloys by a facile one-step hydrothermal method.The morphology,composition,structure and the corrosion resistance of these two LDHs coating before and after corrosion experiment were investigated.It is found that both the two kinds of Zn Al-LDHs films consist of uniform and dense layered nanosheets(NSs),and the NSs of ZnAl-ASP-LDHs films grow vertically,but those of ZnAl-La-LDHs films exhibit a staggered tilted structure.The corrosion current density of the two Zn Al-LDHs films are two orders of magnitude lower than that of Mg alloy substrate.After one week’s immersion in NaCl solution,the NSs structure of two kind of ZnAl-LDHs films still remains the uniform and densely coverage on Mg alloy.Owing to the larger d(003)spacing,the ZnAl-La-LDHs have better ability to absorb Cl-and release interlayer anions than Zn Al-ASP-LDHs.These results indicate that the Zn Al-LDHs films intercalated with organic anions,specially La anions,can significantly improve the corrosion resistance of Mg alloy.

Tailoring crystallization zinc hydroxide sulfates growth towards stable zinc deposition chemistry

The unstable zinc anode/electrolyte interface induced by corrosion,interfacial water splitting reaction,and dendrite growth seriously degrades the performances of metal Zn anode in aqueous electrolyte.Herein,the nucleation and growth of zinc hydroxide sulfate(ZHS),an interfacial by-product,has been tailored by Tween 80 in the electrolyte,which thereby assists in in-situ forming a dense solid electrolyte interphase(SEI)with small-sized ZHS and evenly distributed Tween 80.This SEI has high corrosion resistance and uniform distribution of zinc ions,which not only contributes to blocking the interfacial side reactions but also induces stable and calm zinc plating/stripping.Consequently,the modified electrolyte can confer the assembled Zn||Zn symmetric cell with a stable operation life over 1500 h at 1 mA·cm^(−2)and 1 mAh·cm^(−2)as well as the practical Zn||NH4V4O10 full battery with a high-rate capacity of 120 mAh·g^(−1)at the current density of 5 A·g^(−1).This work provides a way for regulating and reusing interfacial by-products,and a new sight on stabilization electrodes/electrolyte interfaces.