Effects of Cold Rolling and Annealing Prior to Dealloying on the Microstructure of Nanoporous Gold.

Hanyu Hui,Juying Li,Yan Lei,Re Xia,Feng Chen,Qingsong Mei,Ye Ma

doi:10.3390/nano8070540

Hanyu Hui, Juying Li + Show 5 more

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https://doi.org/10.3390/nano8070540

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Abstract

The properties of nanoporous gold (NPG) were known to be dependent on the microstructure of NPG. In this study, the effects of cold rolling and annealing of the original Ag0.7Au0.3 alloy on the microstructure of NPG produced by dealloying under free corrosion condition were investigated. Ag0.7Au0.3 alloy samples were cold-rolled to different strain levels/thickness reductions up to 98% and annealed at 900 °C for 3 h before dealloying. It was found that cold rolling and annealing of the original alloy can lead to reduced ligament and pore sizes of NPG. Moreover, post-deformation annealing of the original alloy was found to facilitate the formation of a homogeneous and continuous NPG structure. The minima of pore and ligament sizes (both being ~8 nm) with uniform distribution were obtained in the annealed sample with a thickness reduction of 60% for a dealloying time of 7 h. The present study indicated the significant effect of a pre-dealloying treatment of the original alloy (by plastic deformation and annealing) on the formation and optimization of the NPG microstructure produced by dealloying.

Highlights

Due to their chemical stability, strength, and high specific surface area, nanoporous metals have attracted great interests in many applications, including catalysis, fuel cells, sensors, and more [1,2]
Studies have revealed that the sizes of pores and ligaments of nanoporous gold (NPG) produced by a dealloying of Ag–Au alloy were influenced by corrosion time, corrosion temperature, and an annealing of samples after corrosion [12,13,14]
The original Ag–Au alloy was subjected to cold rolling and annealing to investigate their effects on the microstructure of NPG produced by subsequent dealloying

Summary

Introduction

Due to their chemical stability, strength, and high specific surface area, nanoporous metals have attracted great interests in many applications, including catalysis, fuel cells, sensors, and more [1,2]. The dealloying of an Ag–Au alloy can produce nanoporous gold (NPG) with an open, three-dimensional bicontinuous interpenetrating ligament-channel structure with nanometer length scales [4,5,7]. Studies have revealed that the sizes of pores and ligaments of NPG produced by a dealloying of Ag–Au alloy were influenced by corrosion time, corrosion temperature, and an annealing of samples after corrosion [12,13,14].

Results

Conclusion