Environment-Sensitive Thermal Coarsening of Nanoporous Gold

In order to investigate environmental effects on the ligament/pore coarsening of nanoporous gold (NPG), we studied the thermal coarsening of NPG both in air and vacuum by ex situ observation, and found that it has high structural stability against heat treatment in vacuum. To clarify the nature of this phenomenon, we investigated the thermal coarsening of NPG by in situ environmental transmission electron microscopy. At an elevated temperature (400 degrees C), the coarsening of ligaments/pores was triggered by introducing either pure N-2 or O-2 gas into the transmission electron microscopy (TEM) chamber (but not by Ar gas). We thus conclude with a discussion on the mechanism for thermal coarsening of NPG.