Thermal coarsening of nanoporous gold: Melting or recrystallization

The thermal coarsening of nanoporous Au was examined and compared with the thermal instability of Au nanoparticles. The nanoporous Au was coarsened at temperatures far below the melting temperature of Au nanoparticles, which possess sizes similar to the nanoligaments. Differential scanning calorimetry characterization of nanoporous Au exhibited an exothermal peak around 470 K. These results suggest that solid-state process like recrystallization, rather than melting, is responsible for the thermal coarsening of nanoporous Au.