Collisional model of nanoparticles molten at high temperature

The collision of nano Al₂O₃ particles is investigated using Molecular Dynamics (MD) at temperatures far exceeding the melting point in order to understand the nano collisions in high-temperature environments. The MD simulation demonstrates two basic modes of collision at the nanoscale: sticking and rebounding, while no breakup or splashing is observed even though considerably high temperature and impact velocities are applied. The phase diagram of sticking and rebounding is influenced by temperature and cannot be well described by the Weber number of droplets. Alternatively, the threshold velocity of sticking and the restitution coefficient are found to well agree with the adhesive elastoplastic contact theory proposed by Thornton and Ning (1998). A semi-analytical model is formulated based on the MD results to describe the restitution coefficient of nano collisions in various cases of velocity, temperature and nano sizes.