We present a facile route to fabricate nanoporous gold composites (NPGCs) through chemical dealloying of two phase Al–Au alloys comprising Al2Au and AlAu intermetallic compounds under free corrosion conditions. The microstructures of the NPGCs were characterized using X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis, and transmission electron microscopy. The dealloying of Al2Au and AlAu separately proceeds, and results in the formation of the NPGCs. The microstructures of the NPGCs are composed of intracellular and intercellular areas which exhibit two kinds of nanoporous structures with different length scales of ligaments/channels. The nanoporous structure of the intracellular areas forms due to the dealloying of Al2Au and that of the intercellular area forms owing to the dealloying of AlAu. Moreover, the proportion of the intercellular areas in the NPGCs increases with increasing Au content in the starting Al–Au alloys. In addition, the length scale of ligaments/channels in the NPGCs can be adjusted by simply changing the dealloying solution. The NPGCs show abnormal coarsening behaviors when subjected to annealing at different temperatures. In comparison to nanoporous gold (NPG) with a homogeneous structure, the NPGCs exhibit higher Young's modulus and yield strength. We can tailor the microstructures, properties and applications of these NPGCs through changing the composition of the starting Al–Au alloys, changing the dealloying solution, and adopting proper post treatment including annealing at high temperatures and acid treatment at room temperature.
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