Annealing process of anisotropic copper nanocrystals. 1. Cylinders

The annealing process of truncated decahedral cylindrical copper particles with 5-fold symmetry (7.5 x 20.5 nm) is presented. The melting point of the cylinders lies below the melting point of the hulk phase. During the annea ling process, various stages of surface diffusion, premelting, and melting take place. Depending on the particle coating with the surfactant, two beha viors are observed. When the nanocrystals are well-coated, they disappear c ompletely at 520 degreesC. At the opposite, when they are not well-coated a nd are placed closely together during the premelting phase (at 380 degreesC ), a percolation process leads to the formation of large aggregates which t end to crystallize again at a melting point far above 520 degreesC.