Microstructure, stability and thermomechanical behavior of crack-free thin films of nanoporous gold

Nanoporous gold thin films were prepared by dealloying and were completely crack-free, with a continuous ligament network across grain boundaries. Film stress increases during dealloying, and thermal cycling causes thermoelastic deformation. Ligament width coarsens during cycling to 200 °C, but at higher temperatures the porous structure densifies. The stability of nanoporous films may also depend on film thickness. From the biaxial film stress, the equivalent yield strength of nanoporous gold was calculated to be at least 1.8 GPa.