On the electrochemical dealloying of Al-based alloys in a NaCl aqueous solution.
On the electrochemical dealloying of Al-based alloys in a NaCl aqueous solution.
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DOI：
10.1039/b919313h
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发表时间：
2010-02
期刊：
影响因子：
--
通讯作者：
Qian Zhang;Zhonghua Zhang
中科院分区：
文献类型：
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作者：
Qian Zhang;Zhonghua Zhang
采用电化学测量和显微组织分析相结合的方法，研究了快速凝固al基合金在1m NaCl水溶液中的电化学脱合金过程。结果表明，通过在NaCl溶液中对al基合金进行电化学脱合金处理，可以制备出各种形貌的纳米多孔金属（Au、Ag、Pd和Cu）。采用开路测量、动电位阳极极化和循环伏安法研究了元素金属（Al、Au、Ag、Pd和Cu）及其合金的电化学行为。通过循环伏安曲线、高于或低于临界电位时的时温曲线以及合金的显微组织特征，分析了前驱体合金的脱合金机制和纳米多孔金属的形成。此外，根据合金中共存相的不同脱合金行为，提出了双相合金的脱合金分类。研究发现，在双相合金的脱合金过程中，共存相之间的相互作用普遍存在，并且原则上依赖于贵金属元素的扩散系数、曲率依赖的欠临界电位溶解以及贵金属元素与氯离子之间的反应。
The electrochemical dealloying of rapidly solidified Al-based alloys in a 1 M NaCl aqueous solution has been investigated using electrochemical measurements in combination with microstructural analysis. The results show that nanoporous metals (Au, Ag, Pd and Cu) with various morphologies can be fabricated through electrochemical dealloying of the Al-based alloys in the NaCl solution. The electrochemical behaviors of elemental metals (Al, Au, Ag, Pd and Cu) and precursor alloys for dealloying have been studied through open-circuit measurements, potentiodynamic anodic polarization and cyclic voltammetry. The dealloying mechanisms of the precursor alloys and the formation of the nanoporous metals have been analyzed based on cyclic voltammetry curves, chronoamperometry curves obtained at potentials above or below the critical potentials, and microstructural features of the as-dealloyed samples. In addition, a classification for dealloying of a bi-phasic alloy has been proposed according to different dealloying behaviors of coexistent phases in the alloy. It has been found that interactions between coexistent phases prevail during dealloying of the bi-phasic alloy and are in principle dependent on the diffusivity of the more noble element, the curvature-dependent undercritical potential dissolution, and the reaction between the more noble element and chloride ion.