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

Abstract

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 μm/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.

The interplay of surface stability and oxygen vacancy dynamics in RE2Si2O7‐based environmental barrier coatings

“…where k B and μ O (T, P • ) represent the Boltzmann constant and temperature-dependent oxygen chemical potential at a pressure of P • (P • = 1 atm), respectively. The V O formation energies, varying with pressure and temperature, can be calculated by incorporating Equations ( 2) and (5).…”

“…With advances in the gas turbines, the requirement to enhance the operating temperature promotes the development of advanced materials serviced under extremely harsh condition. [1][2][3][4][5] As silicon-based ceramics and their ceramic matrix composites (CMCs) show the ability of operating at high temperature with low density, excellent toughness and strength, [6][7][8][9] they are adopted for the promising candidates in the next generation turbine engines, instead of the Ni-based superalloys. [10][11][12][13] Generally, a dense SiO 2 protective film forms on the CMCs surface to prevent the oxidation of the substrate in high-temperatures.…”

An ab initio simulation on electron beam physical vapor deposition of Gd2Zr2O7 coating by density functional theory and kinetic Monte Carlo

“…In fact, many methods have been developed to simulate the growth of coating, including the model of Movchan, 11 Monte Carlo (MC), 12 kinetic MC (KMC), 13 and so forth. Among them, KMC has been used for the nucleation density and morphology of TBC 14,15 because it can well reproduce the EB-PVD deposition process controlled by the Arrhenius equation and iteration. However, in the present stage, it is impossible to perform KMC simulations on the deposition of Gd 2 Zr 2 O 7 as a function of processing parameters, because no potential function is available to describe the interaction among particles.…”