Wetting characteristics of lithium droplet on iron surfaces in atomic scale: A molecular dynamics simulation

Abstract

The wetting characteristics of lithium droplet on different iron surfaces are investigated in details by using molecular dynamics simulations associated with the modified analytic embedded atom model potential. In addition to the wettability of Li droplet on Fe (1 0 0), (1 1 0) and (1 1 2) surfaces, the wetting behavior on a polycrystalline Fe surface is studied. The results show that liquid Li can perfectly wets Fe surfaces, and the wetting behavior of Li droplet is isotropic on Fe (1 0 0) and (1 1 0) surfaces, but anisotropic on Fe (1 1 2) and polycrystalline Fe surfaces. For the Fe (1 1 2) surface, the anisotropic wetting is attributed to the lower energy barriers of Li atom diffusion along the [111¯] orientation on the Fe (1 1 2) surface. We have proposed a new method for describing the wetting behavior of liquid on substrates in atomic scale by measuring the time-dependent ‘contact atom number’. The unified description of the liquid wetting on both single crystal and polycrystalline surfaces is achieved by this method. Li droplet wetting on the Fe (1 1 0) has the fastest spreading rate, and the spreading rate on the polycrystalline Fe surface is only faster than that on the Fe (1 0 0) surface. In addition, the effect of temperature on the wettability is examined, and it is found that the faster spreading occurred with increasing temperature.