Kinetic Monte Carlo simulation of ZrO2 coating deposited by EB-PVD

Kinetic Monte Carlo (KMC) simulations have been used for electron beam physical vapor deposition (EB-PVD) of ZrO2 coatings, with the critical potential function fitted by full first-principles calculations in the framework of density functional theory, emphasizing the effect of critical processing parameters, for example, the substrate temperature (600-1150 K), deposition rate (0.03-7.5 mu m/min), and initial kinetic energy (0-0.5 eV). Here, the interaction between ZrO2 particles is described by coarse grain (CG) model with a numerical non-bonded potential developed by multi-iterative boltzmann inversion (multi-IBI). Overall, the calculated energy barrier by the nudged elastic band (NEB) shows the internal diffusion (3.29-4.80 eV) requires more energy than the surface diffusion (2.90-3.42 eV), because of fewer surrounding particles in the latter. Moreover, the energy barrier of Line Jump is smaller than that of Schwoebel Jump, contributing to the columnar grains rather than a dense coating. Of importance, the simulated morphologies of ZrO2 coatings are well consistent to experiments, with a weaker effect from the substrate temperature, initial kinetic energy to deposition rate. Furthermore, the porosity can be effectively reduced by increasing the temperature and initial kinetic energy, however, with a slight increase when increasing the deposition rate.