Structural evolution in the nanoscale diffusion process: a Au-Sn bimetallic system.
This work shows the structural evolution of a Au-Sn bimetallic system during the nanoscale diffusion process. Based on X-ray absorption fine structure (XAFS) spectroscopy, X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectrometry (EDX), insights were obtained into the detailed composition and structure of the Au-Sn bimetallic system, demonstrating the sequential formation of stable Au/AuSn, AuSn, AuSn/AuSn(2) and AuSn(2) nanocrystals (Au/AuSn and AuSn/AuSn(2) refer to core/shell structures) rather than disordered alloys or alloys with an equal Sn atomic distribution. Furthermore, the formation mechanism of Au-Sn intermetallic compounds and their core/shell structures are discussed. Through elucidating the structural evolution in the diffusion process, we can easily guide the design of other novel bimetallic phases and their core/shell structures which could be predicted between the noble metals (Cu, Ag, Au) and the IIIA or IVA (In, Sn, Pb) metallic elements owing to the rapid diffusion mechanism.
Yu
Kuai
K
Department of Nanomaterials and Nanochemistry, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, P. R. China.
Yao
Tao
T
Pan
Zhiyun
Z
Wei
Shiqiang
S
Xie
Yi
Y