De-alloying kinetics of an Au-based amorphous alloys

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• 作者：Federico Scaglione ; Paola Rizzi ; Livio Battezzati ; ^{livio.battezzati@unito.it}
• 关键词：De-alloying ; Amorphous alloys ; Interfacial kinetics ; Nucleation
• 刊名：Journal of Alloys and Compounds
• 出版年：2012
• 出版时间：25 September, 2012
• 年：2012
• 卷：536
• 期：supp_S1
• 页码：S60-S64
• 全文大小：1109 K

文摘

The process of de-alloying, i.e. removal of a less noble metal from an alloy, is applied here by electrochemical means to a Au-based metallic glass, Au₄₀Cu₂₈Ag₇Pd₅Si₂₀, as a function of potential, temperature, and time. Very fine crystals nucleate with random orientation at the solid-electrolyte interface forming ligaments. The resulting material is constituted by ligaments made of pure Au and pores of smaller size whose dimensions coarsen up as a function of time to slightly above two hundred and below one hundred nanometers, respectively. The microstructure is uniform on both surfaces and across the ribbon. The extent of de-alloying is measured by monitoring the heat of crystallisation of the remaining amorphous phase giving linear trend vs time suggesting the reactions occur on continuously renewed surfaces.