Background

A new synthesis approach was developed for Mg-Fe layered double hydroxide (LDH) film on oxidised magnesium (Mg) alloy WE43 surface by cathodic electrodeposition.

Methods

The synthesised Mg(OH)₂ surface layer provides essential divalent cations and a foundation for the direct growth of an Mg-Fe LDH film through the electrodeposition process with trivalent cations containing solution.

Findings

The cross-section analysis results disclosed that the Mg(OH)₂ layer altered the typical morphology of LDH film, leading to structured LDH nanoplates with a thickness of approximately 3.5 µm. The formation of structured LDH nanoplates resulted from the perpendicular arrangement of the ab-faces of the crystallites to the WE43 surface, as seen from Field Emission Scanning Electron Microscopy (FE-SEM) images. Electrochemical tests in Hank's Balanced Salt Solution (HBSS) report the E_corr value increased by 0.24 V and a decrease in i_corr by one order of magnitude of Mg(OH)₂/Mg-Fe LDH composite films against its substrate. Furthermore, the impedance modulus values of Mg(OH)₂/Mg-Fe LDH composite films can achieve a magnitude of three times greater than its substrate. These results indicate that the Mg-Fe LDH film can effectively capture the corrosion anions during corrosion through the anion-exchange process, making it a promising surface modification for Mg alloy.

中文翻译：

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镁合金WE43上的耐腐蚀Mg(OH)2/Mg-Fe层状双氢氧化物(LDH)复合膜

背景

开发了一种通过阴极电沉积在氧化镁 (Mg) 合金 WE43 表面上制备 Mg-Fe 层状双氢氧化物 (LDH) 膜的新合成方法。

方法

合成的 Mg(OH) ₂表面层提供了必需的二价阳离子，并为通过含三价阳离子溶液的电沉积工艺直接生长 Mg-Fe LDH 膜奠定了基础。

发现

截面分析结果表明，Mg(OH) ₂层改变了LDH膜的典型形态，导致结构化LDH纳米片的厚度约为3.5 µm。起因于的垂直排列结构LDH纳米片的形成AB -faces微晶到WE43表面的，如从场发射扫描电子显微镜（FE-SEM）图像所示。Hank 平衡盐溶液 (HBSS) 中的电化学测试报告称，Mg(OH) ₂ /Mg-Fe LDH 复合膜在其基材上的E _corr值增加了 0.24 V，而i _corr降低了一个数量级。此外，Mg(OH) ₂的阻抗模量值/Mg-Fe LDH复合薄膜可以达到比其基材大三倍的量级。这些结果表明，Mg-Fe LDH 膜可以通过阴离子交换过程有效地捕获腐蚀过程中的腐蚀阴离子，使其成为一种很有前途的镁合金表面改性剂。