Sintering Behavior of Metallic Nanoparticles*

Novel techological applications call increasingly for the controlled production of nanoparticles with well-defined physical properties. An important subject in this field is the sintering of agglomerated particles. We employ two different computer-simulation techniques to simulate the sintering of metallic nanoparticles. Molecular-dynamics simulations are used to study the early stage ($t<\,\approx$100\,ns) of the sintering of two Ni nanoparticles with a size of about 4\,nm. These simulations make it possible to observe important metallurgical details, like the role of (partial) dislocations in the process of the alignment of the crystal lattices. The data of the molecular-dynamics simulations are then used to calibrate the time-scale of kinetic Monte-Carlo simulations which can follow the sintering process over a much longer time-scale. A special technique is used in these simulations which makes it possible to take the misaligned crystal lattices into account.