A comparison of ligament geometries in real and computer-generated nanoporous gold based on cross-section descriptors

Nanoporous gold (np-Au) exhibits a bi-continuous network structure of nanoscale pores and solid ligaments, which form a random 3D network. Geometrical descriptors are developed that allow for characterization, statistical analysis and comparison of a large number of ligaments in real and computer generated np-Au structures. In addition to the voxel resolution and ligament length, the cross-sections of the ligaments are described by roundness, circularity, and compactness. The structures are analyzed in initial and coarsened conditions for various solid fractions. Although the structures do not change topologically, the results confirm significant changes in the geometry during coarsening. It is found that after coarsening the computer-generated structures compare much better to tomographic reconstructions of annealed np-Au structures, although there are still differences in the free ligament length. Therefore, in addition to the topological similarity, similarity of geometrical descriptors is found to be equally important for deriving predictive models based on computergenerated structures.