A Study of the Processes of Structure Formation in Ceramic Coatings by the Kinetic Monte Carlo Method
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y of the Processes of Structure Formation in Ceramic Coatings by the Kinetic Monte Carlo Method A. V. Chernogora*, I. V. Blinkova, and A. P. Demirova a
Russian National Research Technological University “MISiS”(Moscow Institute of Steel and Alloys), Moscow, 119049 Russia *e-mail: [email protected] Received June 17, 2020; revised July 20, 2020; accepted July 23, 2020
Abstract—The processes of structure formation in arc-PVD Ti–Cr–N coatings are studied by computer simulation methods. A new approach to defining the geometric space for determining the positions of atoms relative to the formed dimers and crystallites is proposed. The structure parameters are calculated, and the processes of structure formation in coatings at a potential of 120 V are studied. Keywords: simulation, Monte Carlo, coatings, structure. DOI: 10.1134/S1063785020110036
At the moment, the development of materials with a nanocrystalline structure is among the main directions of development in many fields of science and industry. Developments in the field of coatings are also mainly associated with the formation of a nanocrystalline structure [1–3]. However, the process of development of coatings is a laborious task in view of the large number of components and parameters, as well as due to the complexity of studying the properties of nanostructured materials. In addition to making it possible to substantially reduce the time spent for searching formulations, computer simulation methods can also expand the understanding of the physical processes of coating growth [4–6]. In this study, a model for the growth of multilayer polycrystalline Ti–Cr–N coatings is proposed on the basis of the kinetic Monte Carlo method. This method allows one to perform high-speed numerical integration of deposition processes with a large number of variables. Unlike other methods, such as molecular dynamics simulation, this method allows one to easily relate the integration steps to the physical time scale [7]. Taking into account that the growth of coatings conditionally includes two parallel processes (deposition and diffusion), in which the composition of flow F also depends on time, elapsed time t must be calculated using total diffusion path R traveled by the coating atoms. If the kinetic approach is applied, then all possible acts of diffusion, i.e., transitions Ni, are grouped at each stage of integration according to diffusion barrier Ei, after which total diffusion coefficient R= (N i exp(−Ei /kT )) is calculated. Next, a group of transitions i with a probability proportional to diffu-
sion coefficient Ri of this group of transitions is selected. After that, one of the indicated transitions is implemented with the same probability, while the elapsed time is calculated as Δt = 1/Ri. At each step of integration of the diffusion process, total elapsed time t is calculated by summing time intervals Δt. Diffusion is carried out until the sum of all diffusion acts at a given step remains less than the maximum allowable value, which is calculated as Ndep/(FmaxLy
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