Influence of dealloying solution on the microstructure of nanoporous copper through chemical dealloying of Al 75 Cu 25 r
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FOCUS ISSUE
POROUS METALS: FROM NANO TO MACRO
Influence of dealloying solution on the microstructure of nanoporous copper through chemical dealloying of Al75Cu25 ribbons Hailan Ma1, Bingge Zhao1,a)
, Kai Ding1, Yuanheng Zhang1, Guanzhi Wu1, Yulai Gao1,b)
1
Center for Advanced Solidification Technology (CAST), School of Materials Science and Engineering, Shanghai University, Shanghai 200444, People’s Republic of China a) Address all correspondence to these authors. e-mail: [email protected] b) e-mail: [email protected] Received: 14 December 2019; accepted: 9 March 2020
In this article, Al75Cu25 (at.%) ribbons were dealloyed by HCl, H2C2O4, H3PO4, and NaOH solutions, respectively, to prepare nanoporous copper (NPC). The dealloying behavior is varied with dealloying solutions, allowing modulating the microstructure and porosity of the NPC. Al75Cu25 ribbons are fully dealloyed in HCl, H2C2O4, and NaOH solutions, whereas they are partially dealloyed in H3PO4 solution. Except the NPC prepared in the NaOH solution, no obvious cracks are traced in other samples. The surface diffusivity (Ds) of Cu atoms along the alloy/ solution interfaces is varied with solutions, producing the NPC with different microstructure. NPC with higher specific surface area can be obtained by dealloying the Al75Cu25 ribbons in the HCl solution. Compared with the dealloying in H2C2O4, H3PO4, and NaOH solutions, the dealloying in 10 wt% HCl solution for 25 min at 90 ± 1 °C facilitates the best NPC in this work.
Introduction Nanoporous metals (NPMs), which possess high specific surface area and tunable porosity, have attracted considerable interest in catalysis [1], sensors [2], surface-enhanced Raman scattering (SERS) substrates [3, 4], lithium ion batteries [5], etc. Generally, NPMs can be prepared by template methods [6], like liquid-crystal template [7] and colloidal crystal template [8]. These methods, however, have inherent shortcomings such as technical difficulty, long processing time, and high cost. Therefore, it is important to find an alternative synthesis approach. Recently, the preparation of NPMs by dealloying has attracted wide attention [9, 10]. The so-called dealloying is essentially a selective corrosion process [11, 12], in which the more active component is dissolved away from the precursor alloy, and, simultaneously, the less active component is remained to agglomerate into a nanoporous structure. The dealloying strategy to prepare NPMs has presented the unique advantages such as simplified processing, shorter processing time, and random pore distribution, which makes it more popular over the abovementioned template methods.
ª Materials Research Society 2020
Up to date, numerous attempts have been made to prepare NPMs with dealloying technique, such as Au–Ag [13, 14], Al– Pd [15], Al–Ag [16], and Zn–Ag [17]. However, most of them contain noble components. As the commercial process is taken into consideration, it is necessary to prepare NPMs from lowcost alloys. Consequently, the components like Al, Zn, Mn, and Cu have been e
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