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 annealing process, various stages of surface diffusion, premelting, and melting take place. Depending on the particle coating with the surfactant, two behaviors are observed. When the nanocrystals are well-coated, they disappear completely at 520 degreesC. At the opposite, when they are not well-coated and are placed closely together during the premelting phase (at 380 degreesC), a percolation process leads to the formation of large aggregates which tend to crystallize again at a melting point far above 520 degreesC.