  Kinetic Monte Carlo approach is developed to study aspects of sintering of
dispersed nanoparticles of bimodal size distributions. We explore mechanisms of
neck development when sintering is initiated at elevated temperatures for
nanosize crystalline surfaces of particles of different sizes. Specifically,
the role of smaller particles fitting between larger particles, on the
sintering of the latter is considered. Formation of stable necks bridging
particles at the nanoscale was found to be governed by layering or clustering
mechanisms at the facing surfaces, with clustering leading to a much faster
formation of the bridging structure. Temperature, particle sizes and local
arrangement, as well as other geometrical factors were found to have a profound
effect on sintering mediated by a smaller particle placed in a void between
larger particles.
